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Sample records for cymbopogon citratus dc

  1. BIOAKTIFITAS MINYAK ATSIRI SEREH Cymbopogon citratus DC. TERHADAP PERTUMBUHAN BAKTERI Escherichia coli DAN Staphylococcus aureus

    OpenAIRE

    Rahman, Hasriani

    2013-01-01

    Penelitian ini mengenai bioaktifitas minyak atsiri sereh Cymbopogon citratus DC. terhadap pertumbuhan bakteri Escherichia coli dan Staphylococcus aureus. Penelitian ini bertujuan untuk mengetahui bioaktifitas dan sifat antibakteri minyak atsiri sereh Cymbopogon citratus DC. terhadap pertumbuhan bakteri Escherichia coli dan Staphylococcus aureus. Pengujian daya hambat dilakukan dengan metode difusi agar menggunakan 5 variasi konsentrasi 100%, 50%, 25%, 12,5% dan 6,25% b/v pada media MHA (Mull...

  2. Revue De La Litterature : Cymbopogon citratus (Dc) Stapf ...

    African Journals Online (AJOL)

    Les molécules les plus importantes responsables de ses propriétés thérapeutiques sont : citral, myrcène, limonène, tanins, nerol acetate, neryl acetate, linalool, geranyl acetate, terpin-4-ol, â-caryophyllène, geraniol, saponosides, composés phénoliques, flavonoïdes. Bien que les extraits du C citratus ou certains de ses ...

  3. Cytogenotoxicity of Cymbopogon citratus (DC) Stapf (lemon grass) aqueous extracts in vegetal test systems.

    Science.gov (United States)

    Sousa, Saulo M; Silva, Pâmela S; Viccini, Lyderson F

    2010-06-01

    The lemon grass, Cymbopogon citratus (DC) Stapf, is an important species of Poaceae family commonly used in the folk medicine in many countries. The aim of this study was to investigate the cytotoxic and genotoxic effects of aqueous extracts from C. citratus leaves on Lactuca sativa (lettuce) root tip meristem cells by cytogenetic studies that have never been done before for lemon grass extracts. For this, lettuce seeds were treated for 72h with different concentrations of lemon grass aqueous extracts (5; 10; 20 and 30 mg/mL). The percentage of germination, root development and cellular behavior were analyzed, and the results showed that the highest concentration of aqueous extracts reduced the mitotic index, the seed germination and the root development of lettuce. The extracts have also induced chromosome aberrations and cellular death in the roots cells of L. sativa.

  4. Cytogenotoxicity of Cymbopogon citratus (DC Stapf (lemon grass aqueous extracts in vegetal test systems

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    Saulo M. Sousa

    2010-06-01

    Full Text Available The lemon grass, Cymbopogon citratus (DC Stapf, is an important species of Poaceae family commonly used in the folk medicine in many countries. The aim of this study was to investigate the cytotoxic and genotoxic effects of aqueous extracts from C. citratus leaves on Lactuca sativa (lettuce root tip meristem cells by cytogenetic studies that have never been done before for lemon grass extracts. For this, lettuce seeds were treated for 72h with different concentrations of lemon grass aqueous extracts (5; 10; 20 and 30 mg/mL. The percentage of germination, root development and cellular behavior were analyzed, and the results showed that the highest concentration of aqueous extracts reduced the mitotic index, the seed germination and the root development of lettuce. The extracts have also induced chromosome aberrations and cellular death in the roots cells of L. sativa.O capim-limão, Cymbopogon citratus (DC Stapf, é uma importante espécie da família Poaceae com uma comum utilização na medicina popular em vários países. O objetivo deste estudo foi investigar os efeitos citotóxicos e genotóxicos do extrato aquoso das folhas de C. citratus em células meristemáticas de Lactuca sativa (alface por meio de estudos citogenéticos, uma vez que estudos desta natureza não existem para extratos aquosos de capim-limão. Para isso, sementes de alface foram tratadas por 72h com diferentes concentrações de extratos aquosos feitos das folhas de capim-limão (5, 10, 20 e 30 mg/mL. O percentual de germinação, desenvolvimento radicular e o comportamento celular foram avaliados e os resultados mostraram que as concentrações mais elevadas dos extratos aquosos reduziram o índice mitótico, o percentual de germinação das sementes e desenvolvimento radicular da alface. Os extratos também induziram aberrações cromossômicas e morte celular nas células das raízes de L. sativa.

  5. Evaluation of Antibacterial Activity of Aminoglycosides and Modulating the Essential Oil of Cymbopogon citratus (DC. Stapf

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    Saulo R. TINTINO

    2014-05-01

    Full Text Available  Several works demonstrated the importance of the study of natural products as an alternative source for new antimicrobial drugs or for modulators for these ones. In this point, the aim of this was to investigate the antibacterial activity and the possible interactions between the essential oil of Cymbopogon citratus alone and in association with aminoglycosides against standard and clinically isolated strains of multidrug-resistant bacteria such as S. aureus, E. coli and P. aeruginosa by microdilution method. The results indicated a synergism between the antibiotics and the essential oil with a subinhibitory concentration (MIC/8, reducing the minimal inhibitory concentration (MIC sixteen times against the multidrug-resistant strains of S. aureus 358, E. coli 27 and P. aeruginosa 143, but none modulatory activity was observed against P. aeruginosa 78 and P. aeruginosa 91 strains. By our results, can be concluded that the essential oil of Cymbopogon citratus can be an interesting source of natural products with antibacterial and/or modulatory antibiotic activitieAVALIAÇÃO DA ATIVIDADE ANTIBACTERIANA E MODULADORA DE AMINOGLICOSÍDEOS DO ÓLEO ESSENCIAL DE Cymbopogon citratus (DC. STAPFVários trabalhos vêm demonstrando a importância do estudo de produtos naturais como fonte alternativa para novos antimicrobianos ou que venham potencializar os já existentes. Neste contexto este trabalho teve como objetivo investigar a atividade antibacteriana e as possíveis interações entre o óleo essencial de Cymbopogon citratus combinados a aminoglicosídeos frente a linhagens padrões e multirresistentes de S. aureus, E. coli e de P. aeruginosa provenientes de isolados clínicos. Um ensaio de microdiluição foi realizado para verificar a atividade antibacteriana e as possíveis interacções entre o produto natural e os antibióticos, utilizando uma concentração sub-inibitória. Através dos resultados foi constatado a interferência sinérgica dos

  6. Antimicrobial activity of the essential oil of Cymbopogon citratus (DC) Stapf. on Staphylococcus spp., Streptococcus mutans and Candida spp.

    OpenAIRE

    Almeida, RBA; Akisue,G; Cardoso,LML; Junqueira,JC; AO C Jorge

    2013-01-01

    Medicinal plants with fungicide action, antibacterial and anti-inflammatory effects are under investigation. The main purpose of this work was to evaluate the antimicrobial activity of the essential oil from Cymbopogon citratus (DC) Stapf. on strains of Staphylococcus spp., Streptococcus mutans and Candida spp. with planktonic and biofilm growth. To study the micro-organisms in planktonic cells, the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were deter...

  7. Ethnopharmacology, phytochemistry, and biological activities of Cymbopogon citratus (DC.) Stapf extracts.

    Science.gov (United States)

    Ekpenyong, Christopher E; Akpan, Ernest; Nyoh, Azah

    2015-05-01

    Cymbopogon citratus is a widely distributed perennial herb belonging to the Poaceae family and has been extensively consumed for its medicinal, cosmetic, and nutritional effects for centuries. A large number of reports have been published describing the pharmacological, biological, and therapeutic actions of this herb. In this review, we summarized the literatures on related studies (up to January, 2014) that highlighted the pharmacologic and biological effects of the major phytochemicals isolated from C. citratus extracts and its essential oil. The components of the essential oils found in C. citratus have a similar pharmacokinetic properties, including absorption, distribution, metabolism, and excretion. They are quickly absorbed following oral, pulmonary, and dermal administration. Based on the published reports, it can also be inferred that, after absorption from the small intestine, some phytochemicals in C. citratus can undergo oxidation, glucuronidation, sulfation, and/or O-methylation. Excretion is through urine, feces and/or expired volatiles. The biotransformation reactions of C. citratus bioactive constituents are essential for its relatively safe consumption and therapeutic applications. The data available so far warrant further studies evaluating C. citratus pharmacokinetics. Reliable pharmacokinetic data in humans would be critical for a better understanding of the the systemic handling of C. citratus. Copyright © 2015 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  8. Larvicidal activity of Cymbopogon citratus (DC) Stapf. and Croton macrostachyus Del. against Anopheles arabiensis Patton, a potent malaria vector.

    Science.gov (United States)

    Karunamoorthi, K; Ilango, K

    2010-01-01

    Methanol leaf extracts of two Ethiopian traditional medicinal plants viz., Lomisar [vernacular name (local native language, Amharic); Cymbopogon citratus (DC) Stapf. (Poaceae)] and Bisana [vernacular name (local native language, Amharic); Croton macrostachyus Del. (Euphorbiaceae)] were screened for larvicidal activity against late third instar larvae of Anopheles arabiensis Patton, a potent malaria vector in Ethiopia. The larval mortality was observed 24 h of post treatment. Both plant extracts demonstrated varying degrees of larvicidal activity against Anopheles arabiensis. Cymbopogon citratus extract has exhibited potent larvicidal activity than Croton macrostachyus at lower concentrations. The LC50 and LC90 values of Cymbopogon citratus were 74.02 and 158.20 ppm, respectively. From this data, a chi-square value 2.760 is significant at the P < 0.05 level. While, the LC50 and LC90 values of Croton macrostachyus were 89.25 and 224.98 ppm, respectively and the chi-square value 1.035 is significant at the P < 0.05 level. The present investigation establishes that these plant extracts could serve as potent mosquito larvicidal agents against Anopheles arabiensis. However, their mode of actions and larvicidal efficiency under the field conditions should be scrutinized and determined in the near future.

  9. Cellular Suspensions Establishment and Multiplication of Cymbopogon citratus (D.C Staff

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    Elisa Quiala

    2002-07-01

    Full Text Available Cellular suspensions settled down starting from callus of Cymbopogon citratus (D.C Stapf cultivated in semisolid medium, according to the methodology described for Freire (1998, for the cultivation of the cane of sugar and later on modified by Licea and Gómez (2000 for the cultivated callus of Cane Santa, with the objective of analyzing the effect of the cellular density on the cellular growth, being studied the behavior of the fresh mass, dry mass and the pH in three inocule densities (20, 40 and 60 gMF.l-1. The development of roots was evaluated in the cellular aggregated and it was also analyzed directly the influence of the explants on the callus formation cultivated directly in liquid medium, starting from cultivated plants in vitro. The biggest increment of fresh mass was obtained when 20 gMF.l-1 was used, the values of mass dry off they behaved in a similar way, being obtained the biggest rate of growth in this same treatment. The pH in the three densities of studied inocule, diminished during the first eight days and stayed stable starting from this moment. The alone presence of roots was appreciated only in the cellular aggregated cultivated without coconut water. The formation of callus directly in liquid medium took place in the region near to the meristematic area. Key words: coconut water, biomass production, lemon grass, root formation

  10. Comparative anticonvulsant activities of the essential oils (EOs) from Cymbopogon winterianus Jowitt and Cymbopogon citratus (DC) Stapf. in mice.

    Science.gov (United States)

    Silva, Monalisa Ribeiro; Ximenes, Rafael Matos; da Costa, José Galberto Martins; Leal, L Kalyne A M; de Lopes, Amanda A; Viana, Glauce Socorro de Barros

    2010-05-01

    The fresh leaves of Cymbopogon citratus are a good source of an essential oil (EO) rich in citral, and its tea is largely used in the Brazilian folk medicine as a sedative. A similar source of EO is Cymbopogon winterianus, rich in citronellal. The literature presents more studies on the EO of C. citratus and their isolated bioactive components, but only a few are found on the EO of C. winterianus. The objective of the present study was then to study, in a comparative way, the effects of both EOs on three models of convulsions (pentylenetetrazol, pilocarpine, and strychnine) and on the barbiturate-induced sleeping time on male Swiss mice. The animals (20-30 g) were acutely treated with 50, 100, and 200 mg kg(-1), intraperitoneally, of each EO, and 30 min later, the test was initiated. The observed parameters were: latency to the first convulsion and latency to death in seconds. Furthermore, the in vitro effects of the EOs were also studied on myeloperoxidase (MPO; a biomarker for inflammation) and lactate dehydrogenase (LDH; an index of cytotoxicity) releases from human neutrophils. The EOs radical-scavenging activities were also evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The results showed that both EOs were more active on the pentylenetetrazol-induced convulsion model, and C. citratus was even more efficient in increasing latency to the first convulsion and latency to death. Both parameters were potentiated in the presence of a lower dose of diazepam (reference drug) when associated to a lower dose of each EO (25 mg kg(-1)). Besides, their anticonvulsant effects were blocked by flumazenil, a known benzodiazepine antagonist. This effect was somewhat lower on the pilocarpine-induced convulsion, and better effects were seen only with the EOs' higher doses (200 mg kg(-1)). A similar result was observed on the strychnine-induced convulsion model. Both EOs potentiated the barbiturate-induced sleeping time. However, C. citratus was more efficient

  11. Antimicrobial activity of the essential oil of Cymbopogon citratus (DC Stapf. on Staphylococcus spp., Streptococcus mutans and Candida spp.

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    RBA Almeida

    2013-01-01

    Full Text Available Medicinal plants with fungicide action, antibacterial and anti-inflammatory effects are under investigation. The main purpose of this work was to evaluate the antimicrobial activity of the essential oil from Cymbopogon citratus (DC Stapf. on strains of Staphylococcus spp., Streptococcus mutans and Candida spp. with planktonic and biofilm growth. To study the micro-organisms in planktonic cells, the minimal inhibitory concentration (MIC and minimal bactericidal concentration (MBC were determined by using 9 clinical strains for each species and 1 ATCC (American Type Culture Collection from C. albicans, C. tropicalis, C. glabrata, S. aureus, S. epidermidis and S. mutans. In order to evaluate the effects of the essential oils on biofilms, strains of S. aureus (ATCC 6538, S. mutans (ATCC 35688 and C. albicans (ATCC 18804 were used. The biofilm was formed on acrylic resin discs with isolated micro-organisms or in associations. The number of colony-forming-units (CFU obtained in each biofilm (CFU/ml was submitted to Student's t statistical test. The results demonstrated that the essential oil of Cymbopogon citratus showed microbiostatic and microbicidal activity against all tested strains. The average CFU/ml for the biofilm of S. aureus, S. mutans and C. albicans, whether isolated or in association, was lower in the group treated with essential oil than in the control group.

  12. Evaluation of the Chemical Composition of Brazilian Commercial Cymbopogon citratus (D.C. Stapf Samples

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    Evandro de Castro Melo

    2008-08-01

    Full Text Available Abstract: The concentration and the chemical composition of the essential oils obtained from different samples of Cymbopogon citratus were evaluated. Among the 12 samples investigated (11 dried leaf samples and fresh plant leaves, seven presented essential oil concentrations within the threshold established by the Brazilian legislation. The moisture content was also determined and the majority of the samples presented humidity contents near 12%. The GC and GC/MS analyses of the essential oils led to identification of 22 compounds, with neral and geranial as the two major components. The total percentage of these two compounds varied within the investigated sample oils from 40.7% to 75.4%. In addition, a considerable variation in the chemical composition of the analyzed samples was observed. The process of grinding the leaves significantly decreased (by up to 68% the essential oil content, as well as the percentage of myrcene in the oils.

  13. Evaluation of the chemical composition of Brazilian commercial Cymbopogon citratus (D.C.) stapf samples.

    Science.gov (United States)

    Barbosa, Luiz Cláudio Almeida; Pereira, Ulisses Alves; Martinazzo, Ana Paula; Maltha, Célia Regina Alvares; Teixeira, Róbson Ricardo; Melo, Evandro de Castro

    2008-08-27

    The concentration and the chemical composition of the essential oils obtained from different samples of Cymbopogon citratus were evaluated. Among the 12 samples investigated (11 dried leaf samples and fresh plant leaves), seven presented essential oil concentrations within the threshold established by the Brazilian legislation. The moisture content was also determined and the majority of the samples presented humidity contents near 12%. The GC and GC/MS analyses of the essential oils led to identification of 22 compounds, with neral and geranial as the two major components. The total percentage of these two compounds varied within the investigated sample oils from 40.7% to 75.4%. In addition, a considerable variation in the chemical composition of the analyzed samples was observed. The process of grinding the leaves significantly decreased (by up to 68%) the essential oil content, as well as the percentage of myrcene in the oils.

  14. Chemical composition and cardiovascular effects induced by the essential oil of Cymbopogon citratus DC. Stapf, Poaceae, in rats

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    Flávia V. Moreira

    2010-08-01

    Full Text Available Cymbopogon citratus DC. Stapf, Poaceae, is used in the folk medicine for hypertension treatment. This work investigated the chemical composition and cardiovascular effects in rats of C. citratus essential oil (EOCC. A phytochemical screening demonstrated the presence of eight constituents, being geranial the major compound (43.08%. In rats, EOCC (1, 5, 10, and 20 mg/kg, i.v. induced transient hypotension and bradycardia that were attenuated by atropine and sodium thiopental, but not by L-NAME or indomethacin. In rings of rat superior mesenteric artery pre-contracted with phenylephrine, EOCC (1 to 3000 µg/mL induced relaxation that was not affected after removal of the endothelium, after TEA or in rings pre-contracted with KCl (80 mM. Furthermore, EOCC (1000 µg/mL was not able to induce additional effect on maximal relaxation of nifedipine (10 µM. In conclusions, EOCC induces hypotension, possibly by reduction in vascular resistance caused by inhibition of the Ca2+ influx, and bradycardia probably due to an activation of cardiac muscarinic receptors.

  15. Effect of vermicompost, worm-bed leachate and arbuscular mycorrizal fungi on lemongrass (Cymbopogon citratus (DC) Stapf.) growth and composition of its essential oil

    OpenAIRE

    León-Anzueto,Elizabeth; Abud-Archila, Miguel; Dendooven, Luc; Ventura-Canseco,Lucía María Cristina; Federico A. Gutiérrez-Miceli

    2011-01-01

    The objective of this study was to investigate the effect of vermicompost, worm-bed leachate (WBL) and Glomus mosseae, an arbuscular mycorrhizal fungi (AMF), on growth of lemongrass (Cymbopogon citratus (DC.) Stapf). A response surface methodology, i.e. a three-level Box Benhen design with three repetitions and three blocks, was applied to optimize biomass production, essential oil yield and its composition. Application rates of Glomus mosseae were 0, 1 or 2 g plant-1, vermicompost 0, 5 or 10...

  16. Estudio de Estabilidad de una Loción Facial Actiacné a base de Aceite Esencial de Hierba Luisa Cymbopogon citratus (DC) STAPF, POACEAE.

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    Gallegos Medina, Wilma de las Mercedes

    2015-01-01

    The research develops an acne lotion with essential oil of lemongrass Cymbopogon citratus (DC) STAPF, POACEAE, under guidelines of the national and international law, which allows obtaining a product considered stable and safe. The formulation is established based on a full factorial design with two factors and three levels, taking as variables the ingredients that affect the organoleptic of the lotion, in this case: : emollient to 60, 50, 35%, the surfactant to 15, 10, 5%, and in two runs or...

  17. Controle da ferrugem das folhas do capim-limão [Cymbopogon citratus (DC: Stapf] com produtos naturais Rust control in leaves of lemongrass [Cymbopogon citratus (DC: Stapf] by using natural products

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    E.R. Lorenzetti

    2012-01-01

    Full Text Available Cymbopogon citratus (DC. Stapf é uma planta medicinal pertencente a família Poaceae, perene, importante para a indústria farmacêutica e alimentícia devido ao óleo essencial que produz. Um problema limitante para a produção comercial é a ferrugem, doença cujo agente etiológico é o fungo Puccinia nakanishikii Dietel. O presente trabalho objetivou avaliar a ação de produtos naturais no controle da doença in vitro e in vivo. Para os testes in vitro, empregaram-se os seguintes produtos sobre a germinação de esporos do patógeno: óleos essenciais de eucalipto, palma-rosa, cravo-da-índia, menta, limão, citronela e mil-folhas; extrato pirolenhoso de eucalipto e mentol cristalizado, em diferentes concentrações. Para os testes de campo foram selecionados quatro produtos, o óleo de citronela e de eucalipto, o extrato pirolenhoso, e o mentol. In vitro, todos os agentes mostraram-se promissores no controle do patógeno. Quando em condições in vivo, sob alta severidade da doença no ato da avaliação, os produtos testados foram capazes de reduzir a severidade da doença em comparação com a testemunha. O controle da doença com os agentes naturais variou de 38% (extrato pirolenhoso a 61%(óleo essencial de eucalipto.Cymbopogon citratus (DC. Stapf is a medicinal plant that belongs to the Poaceae family; it is perennial and important for the pharmaceutical and food industry due to the essential oil it produces. A limiting problem for commercial production is rust, a disease that has as etiological agent the fungus Puccinia nakanishikii Dietel. The present study aimed to evaluate the action of natural products on the disease control, in vitro and in vivo. For the in vitro tests, the following products were employed on the germination of the pathogen spores: essential oils from eucalyptus, palmarosa, clove, peppermint, lemon, citronella and yarrow, pyroligneous extract from eucalyptus, and crystallized menthol, at different

  18. Efecto anti-Trypanosoma cruzi del aceite esencial de Cymbopogon citratus (DC Stapf (hierba luisa en ratones Balb/c

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    Juan Rojas

    2012-01-01

    Full Text Available Objetivo: Determinar la actividad anti-Trypanosoma cruzi in vivo del aceite esencial de Cymbopogon citratus en ratones Balb/c. Diseño: Estudio experimental, prospectivo. Institución: Instituto de Investigaciones Clínicas e Instituto de Medicina Tropical de la Facultad de Medicina de la Universidad Nacional Mayor de San Marcos, Lima, Perú. Material biológico: Aceite esencial de Cymbopogon citratus; ratones albinos Balb/c. Intervenciones: Los animales fueron asignados aleatoriamente a seis grupos de 15 ratones cada uno: infectados y no tratados (G1, infectados y tratados con benznidazol 100 mg/kg (G2, infectados y tratados con aceite esencial de Cymbopogon citratus 100 mg/kg y 250 mg/kg (G3 y G4, respectivamente, no infectados y no tratados (G5, y no infectados y tratados con 250 mg de Cymbopogon citratus (G6. La infección con T. cruzi se realizó con 10(4 trypomastigotes sanguíneos y el tratamiento empezó en el 8º día post infección (dpi hasta el 28° dpi. La parasitemia se determinó con microscopia óptica cada dos días en 5 µL de sangre de la cola. En el 14°, 21° y 28° dpi, cinco animales de cada grupo fueron sacrificados y se removió el corazón para estudio histopatológico. Principales medidas de resultados: Parasitemia, número de nidos de amastigotes e infiltrados inflamatorios. Resultados: El aceite esencial de Cymbopogon citratus 250 mg/kg/día produjo una reducción significativa en el pico de parasitemia desde 113,92 ± 25,66 hasta 74,60 ± 12,37 tripomastigotes/mL (p < 0,05. Con 100 mg/kg/día se produjo una reducción hasta 77,40 ± 14,93 tripomastigotes/ mL (p < 0,05. También redujo el número de amastigotes y de infiltrados inflamatorios en el corazón. Conclusiones: El aceite esencial de Cymbopogon citratus tuvo efecto anti-Trypanosoma cruzi en ratones Balb/c en lo referente a la disminución de la parasitemia, el número de nidos de amastigotes y los resultados inflamatorios.

  19. Controle de plantas invasoras em cultivo orgânico e convencional de capim-limão (Cymbopogon citratus (DC) Stapf.)

    OpenAIRE

    Lemos,G.C.S.; Santos, A D; S.P. Freitas; GRAVINA, G. de A.

    2013-01-01

    O cultivo orgânico é preconizado para o capim-limão (Cymbopogon citratus (DC) Stapf.) como planta medicinal promissora ao desenvolvimento de fármacos no Brasil. Objetivou-se avaliar técnicas de controle de plantas invasoras sobre componentes de produção de capim limão em cultivos orgânico e convencional. Dois experimentos foram instalados sob delineamento inteiramente casualizado, com quatro repetições, em esquema fatorial 2x2x3, considerando-se duas áreas (orgânico e convencional) e os trata...

  20. Inhibitory activity of Syzygium aromaticum and Cymbopogon citratus (DC. Stapf. essential oils against Listeria monocytogenes inoculated in bovine ground meat

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    Thales Leandro Coutinho de Oliveira

    2013-01-01

    Full Text Available This research evaluated the antimicrobial effect of the clove (Syzygium aromaticum and lemongrass (Cymbopogon citratus (DC. Stapf. essential oils (EOs against Listeria monocytogenes ATCC 19117 growth added to bovine ground meat stored under refrigeration (5 ± 2 °C for three days. The EOs, extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS, were tested in vitro using an agar well diffusion methodology for determination of Minimum Inhibitory Concentration (MIC. The MIC concentrations for both essential oils on culture tested of L. monocytogenes were 1.56%. The EOs concentrations applied in contaminated ground beef were 1.56, 3.125 and 6.25% (w/v based on MIC levels and possible activity reductions by food constituents. The bacteria populations were significantly reduced (p < 0.05 after one day of storage in ground meat samples treated with clove and lemongrass EOs at concentrations of 1.56%. There were no significant counts of L. monocytogenes in samples at the other concentrations of the two oils applied after the second day of storage. The sensory acceptability evaluation of the bovine ground meat samples treated with EOs showed that the addition at concentrations higher than 1.56% promote undesirable alterations of taste, odor and characteristic color. The application of EOs at low concentrations in food products can be used in combination with other preservation methods, such as refrigeration, to control pathogens and spoilage bacteria during shelf-life; which goes according to current market trends, where consumers are requesting natural products.

  1. Inhibitory activity of Syzygium aromaticum and Cymbopogon citratus (DC.) Stapf. essential oils against Listeria monocytogenes inoculated in bovine ground meat.

    Science.gov (United States)

    de Oliveira, Thales Leandro Coutinho; das Graças Cardoso, Maria; de Araújo Soares, Rodrigo; Ramos, Eduardo Mendes; Piccoli, Roberta Hilsdorf; Tebaldi, Victor Maximiliano Reis

    2013-01-01

    This research evaluated the antimicrobial effect of the clove (Syzygium aromaticum) and lemongrass (Cymbopogon citratus (DC.) Stapf.) essential oils (EOs) against Listeria monocytogenes ATCC 19117 growth added to bovine ground meat stored under refrigeration (5 ± 2 °C) for three days. The EOs, extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS), were tested in vitro using an agar well diffusion methodology for determination of Minimum Inhibitory Concentration (MIC). The MIC concentrations for both essential oils on culture tested of L. monocytogenes were 1.56%. The EOs concentrations applied in contaminated ground beef were 1.56, 3.125 and 6.25% (w/v) based on MIC levels and possible activity reductions by food constituents. The bacteria populations were significantly reduced (p ≤ 0.05) after one day of storage in ground meat samples treated with clove and lemongrass EOs at concentrations of 1.56%. There were no significant counts of L. monocytogenes in samples at the other concentrations of the two oils applied after the second day of storage. The sensory acceptability evaluation of the bovine ground meat samples treated with EOs showed that the addition at concentrations higher than 1.56% promote undesirable alterations of taste, odor and characteristic color. The application of EOs at low concentrations in food products can be used in combination with other preservation methods, such as refrigeration, to control pathogens and spoilage bacteria during shelf-life; which goes according to current market trends, where consumers are requesting natural products.

  2. Treatment of pityriasis versicolor with topical application of essential oil of Cymbopogon citratus (DC) Stapf - therapeutic pilot study.

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    Carmo, Egberto Santos; Pereira, Fillipe de Oliveira; Cavalcante, Neuza Maria; Gayoso, Carla Wanderley; Lima, Edeltrudes de Oliveira

    2013-01-01

    Pityriasis versicolor is a fungal infection caused by Malassezia spp. that has frequent relapses. The main objective of this research was to perform phase I and II clinical studies, using formulations containing essential oil of Cymbopogon citratus in patients with pityriasis versicolor. Phase I study included twenty volunteers to ascertain the safety of the formulations. In phase II, 47 volunteers randomly received essential oil formulations at 1.25 μL/mL concentration, for forty days. The shampoo should be applied three times a week and the cream twice a day. A control group in phase II, consisting of 29 volunteers, received the same formulations but with 2% ketoconazole as the active ingredient. No significant adverse events were observed in volunteers during Phase I. In Phase II, 30 (63.83%) volunteers using essential oil and 18 (62.07%) using ketoconazole remained until the end of the study. We observed a predominance of lesions in disseminated form, with M. sympodialis detected as the predominant agent identified in cultures. After 40 days of treatment, the rate of mycological cure was 60% (p citratus and over 80% (p citratus, further studies with larger populations should be performed to confirm the actual potential of these formulations in the treatment of patients with Pityriasis versicolor.

  3. Treatment of pityriasis versicolor with topical application of essential oil of Cymbopogon citratus (DC) Stapf - therapeutic pilot study*

    Science.gov (United States)

    Carmo, Egberto Santos; Pereira, Fillipe de Oliveira; Cavalcante, Neuza Maria; Gayoso, Carla Wanderley; Lima, Edeltrudes de Oliveira

    2013-01-01

    BACKGROUND Pityriasis versicolor is a fungal infection caused by Malassezia spp. that has frequent relapses. OBJECTIVES The main objective of this research was to perform phase I and II clinical studies, using formulations containing essential oil of Cymbopogon citratus in patients with pityriasis versicolor. METHODS Phase I study included twenty volunteers to ascertain the safety of the formulations. In phase II, 47 volunteers randomly received essential oil formulations at 1.25 μL/mL concentration, for forty days. The shampoo should be applied three times a week and the cream twice a day. A control group in phase II, consisting of 29 volunteers, received the same formulations but with 2% ketoconazole as the active ingredient. RESULTS No significant adverse events were observed in volunteers during Phase I. In Phase II, 30 (63.83%) volunteers using essential oil and 18 (62.07%) using ketoconazole remained until the end of the study. We observed a predominance of lesions in disseminated form, with M. sympodialis detected as the predominant agent identified in cultures. After 40 days of treatment, the rate of mycological cure was 60% (p citratus and over 80% (p citratus, further studies with larger populations should be performed to confirm the actual potential of these formulations in the treatment of patients with Pityriasis versicolor. PMID:23793205

  4. Free radical scavengers from Cymbopogon citratus (DC.) stapf plants cultivated in bioreactors by the temporary immersion (TIS) principle.

    Science.gov (United States)

    Tapia, Alejandro; Cheel, José; Theoduloz, Cristina; Rodríguez, Jaime; Schmeda-Hirschmann, Guillermo; Gerth, Andre; Wilken, Dirk; Jordan, Miguel; Jiménez-González, Elio; Gomez-Kosky, Rafael; Mendoza, Elisa Quiala

    2007-01-01

    The biomass production of Cymbopogon citratus shoots cultivated in bioreactors according to the temporary immersion (TIS) principle was assessed under different growth conditions. The effect of gassing with CO2-enriched air, reduced immersion frequency, vessel size and culture time on total phenolic and flavonoid content and free radical scavenging effect of the methanolic extracts was measured. From the TIS-culture of C. citratus, seven compounds were isolated and identified as caffeic acid (1), chlorogenic acid (2), neochlorogenic acid (3), p-hydroxybenzoic acid (4), p-hydroxybenzoic acid 3-O-beta-D-glucoside (5), glutamic acid (6) and luteolin 6-C-fucopyranoside (7). The occurrence of compounds 1-7 and their variability in C. citratus grown under different TIS conditions was determined by HPLC. The free radical scavenging effect of the methanolic extract and compounds was measured by the discoloration of the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). The main metabolites in 6- and 8-week-old cultures, both in 5 and 10 1 vessels, were chlorogenic acid (2) (100-113 mg%) and neochlorogenic acid (3) (80-119 mg%), while in the cultures with CO2-enriched air and reduced immersion frequency the main compound detected in the extracts was glutamic acid (6) (400 and 670 mg% for the green and white biomass and 619 and 630 mg% for the green and white biomass, respectively). The most active compounds, as free radical scavengers, in the DPPH discoloration assay were caffeic acid (1), chlorogenic acid (2), neochlorogenic acid (3) and the flavonoid luteolin 6-C-fucopyranoside (7).

  5. Trace and Essential Elements Analysis in Cymbopogon citratus (DC.) Stapf Samples by Graphite Furnace-Atomic Absorption Spectroscopy and Its Health Concern

    Science.gov (United States)

    Anal, Jasha Momo H.

    2014-01-01

    Cymbopogon citratus (DC.) Stapf commonly known as lemon grass is used extensively as green tea and even as herbal tea ingredient across the world. Plants have the ability to uptake metals as nutrient from the soil and its environment which are so essential for their physiological and biochemical growth. Concentrations of these twelve trace elements, namely, Mg, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Mo, As, Cd, and Pb, are analysed by graphite furnace-atomic absorption spectroscopy (GF-AAS) and are compared with the permissible limits of FAO/WHO, ICMR, and NIH, USA, which are found to be within permissible limits. Toxic metals like As, Cd, and Pb, analysed are within the tolerable daily diet limit and at low concentration. PMID:25525430

  6. Trace and Essential Elements Analysis in Cymbopogon citratus (DC.) Stapf Samples by Graphite Furnace-Atomic Absorption Spectroscopy and Its Health Concern.

    Science.gov (United States)

    Anal, Jasha Momo H

    2014-01-01

    Cymbopogon citratus (DC.) Stapf commonly known as lemon grass is used extensively as green tea and even as herbal tea ingredient across the world. Plants have the ability to uptake metals as nutrient from the soil and its environment which are so essential for their physiological and biochemical growth. Concentrations of these twelve trace elements, namely, Mg, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Mo, As, Cd, and Pb, are analysed by graphite furnace-atomic absorption spectroscopy (GF-AAS) and are compared with the permissible limits of FAO/WHO, ICMR, and NIH, USA, which are found to be within permissible limits. Toxic metals like As, Cd, and Pb, analysed are within the tolerable daily diet limit and at low concentration.

  7. Trace and Essential Elements Analysis in Cymbopogon citratus (DC. Stapf Samples by Graphite Furnace-Atomic Absorption Spectroscopy and Its Health Concern

    Directory of Open Access Journals (Sweden)

    Jasha Momo H. Anal

    2014-01-01

    Full Text Available Cymbopogon citratus (DC. Stapf commonly known as lemon grass is used extensively as green tea and even as herbal tea ingredient across the world. Plants have the ability to uptake metals as nutrient from the soil and its environment which are so essential for their physiological and biochemical growth. Concentrations of these twelve trace elements, namely, Mg, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Mo, As, Cd, and Pb, are analysed by graphite furnace-atomic absorption spectroscopy (GF-AAS and are compared with the permissible limits of FAO/WHO, ICMR, and NIH, USA, which are found to be within permissible limits. Toxic metals like As, Cd, and Pb, analysed are within the tolerable daily diet limit and at low concentration.

  8. GC-MS evaluation of Cymbopogon citratus (DC) Stapf oil obtained using modified hydrodistillation and microwave extraction methods.

    Science.gov (United States)

    Ajayi, E O; Sadimenko, A P; Afolayan, A J

    2016-10-15

    Bioactive compounds of Cymbopogon citratus essential oil, using different media have been tentatively identified with the aid of gas chromatography-mass spectrometry (GC-MS). Hydrodistillation was complemented using weakly acidic and alkaline media for the oil extraction. Solvent-free microwave extraction (SFME) was also used. Analyses of the oils revealed the presence of 7, 16, 22, and 15 compounds in the water-distilled (WD), microwave-distilled (MD), acid-distilled (AD), and base-distilled (BD), essential oils, respectively. Total yield of the volatile fractions was 0.73%, 0.64%, 0.70%, and 0.45%, respectively. Citral was found to be the major component, the base extraction having the highest content. This was followed by 2-isopropenyl-5-methylhex-4-enal, p-cymene, and 2-thujene. The antimicrobial, antibacterial, and antioxidant activities and assessment of medicinal/nutritional uses of the essential oils are subjects of future studies. Copyright © 2016. Published by Elsevier Ltd.

  9. Effet comparé des poudres de Nicotiana tabacum L, Cymbopogon citratus (D.C. Stapf et de l'huile de Ricinus communis L sur la conservation des graines de Vigna unguiculata (L Walp

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    Gakuru, S.

    1995-01-01

    Full Text Available Compared Effect of Nicotiana tabacum L, Cymbopogon citratus (D.C. Stapf Powders and Castor Oil Ricinus communis L. on Conservation of Cowpea Vigna Unguiculata (L. Walp Grains. The effect of powder of tobacco Nicotiana tabacum L. and citronella grass Cymbopogon citratus (D.C. Stapf and castor oil Ricinus communis L. on conservation of cowpea Vigna unguiculata (L. Walp. grains was investigated in Kisangani, Zaire. After 5 months of conservation, infestation rates by bean weevil Acanthoscelides obtectus Say were 72.5 %, 74.5 %, 49.5 % and 5 % respectively for the check, the samples treated by 1 % of citronella grass and tobacco powder and 1 % of castor oil. The powder dose of 7.5 % did not give more interesting results.

  10. Control of anthracnose caused by Colletotrichum species in guava, mango and papaya using synergistic combinations of chitosan and Cymbopogon citratus (D.C. ex Nees) Stapf. essential oil.

    Science.gov (United States)

    Lima Oliveira, Priscila Dinah; de Oliveira, Kataryne Árabe Rimá; Vieira, Willie Anderson Dos Santos; Câmara, Marcos Paz Saraiva; de Souza, Evandro Leite

    2018-02-02

    This study assessed the efficacy of chitosan (Chi) and Cymbopogon citratus (D.C. ex Nees) Stapf. essential oil (CCEO) combinations to control the mycelial growth of five pathogenic Colletotrichum species (C. asianum, C. siamense, C. fructicola, C. tropicale and C. karstii) in vitro, as well as the anthracnose development in guava (Psidium guajava L.) cv. Paluma, mango (Mangifera indica L.) cv. Tommy Atkins and papaya (Carica papaya L.) cv. Papaya artificially inoculated with these species. Combinations of Chi (2.5, 5 or 7.5mg/mL) and CCEO (0.15, 0.3, 0.6 or 1.25μL/mL) inhibited the mycelial growth of all tested fungal species in vitro. Examined Chi-CCEO combinations showed additive or synergistic interactions to inhibit the target Colletotrichum species based on the Abbott index. Coatings formed by synergistic Chi (5mg/mL) and CCEO (0.15, 0.3 or 0.6μL/mL) combinations decreased anthracnose lesion development in guava, mango and papaya inoculated with any of the tested Colleotrichum species during storage. Overall, anthracnose lesion development inhibition in fruit coated with synergistic Chi-CCEO combinations was higher than that observed in fruit treated with synthetic fungicides. These results show that the application of coatings formed by Chi-CCEO synergistic combinations could be effective to control postharvest anthracnose development in fruit. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Comparative morphological and anatomical characteristics of the species known as lemongrass (limonotu): Melissa officinalis L., Cymbopogon citratus (DC) Stapf. and Aloysia citriodora Palau.

    OpenAIRE

    Emine Akalın, Yeter Yeşil,

    2016-01-01

    Abstract: Aloysia citriodora (Verbenaceae), Melissa officinalis (Lamiaceae) and Cymbopogon citratus (Poaceae) leaves have a gentle lemon-scented essential oil, contains citral or citronellal and are called the Lemongrass in Turkey. This similarity causes the use of plants for the same purposes despite the presence of different families and different morphological and anatomical structure. Instead of Melissa officinalis, which grows naturally in our country, Aloysia citriodora samples are sold...

  12. Microscopic investigation to determine the effect of Beauveria bassiana (Bals.) Vuill. and Cymbopogon citratus (DC.) Stapf. treatment on different life stages of Musca domestica (L.).

    Science.gov (United States)

    Mishra, Sapna; Kumar, Peeyush; Malik, Anushree

    2017-06-01

    Microscopic investigation was done to determine the effect of entomopathogenic fungi, Beauveria bassiana and essential oil of Cymbopogon citratus on different life stages of Musca domestica. Scanning electron microscopy investigation of fungal infected larvae showed sluggish movement, rigor, and failure of body to balance in water. Treated larvae also revealed varied level of cuticle shrinkage and extreme dehydration. Surface of B. bassiana infected pupae showed varied stage of mycelial growth, while the cadaver of adult fly was observed to have extensive fungal growth covering their entire body surface. The application of C. citratus oils on M. domestica larvae resulted in skin shrinkage, spinous cells proliferation and bleb formation, while the treated pupae showed high incidence of incomplete emergence and malformation in emerged adult flies. The current study establishes effect of C. citratus essential oil and B. bassiana infection on different life stages of M. domestica.

  13. Assessment of Cymbopogon citratus (DC.) stapf essential oil as herbal preservatives based on antifungal, antiaflatoxin, and antiochratoxin activities and in vivo efficacy during storage.

    Science.gov (United States)

    Sonker, Nivedita; Pandey, Abhay K; Singh, Pooja; Tripathi, N N

    2014-04-01

    Thirty-five randomly collected samples of stored table grapes (Vitis vinifera L.) from different markets of Gorakhpur city, Uttar Pradesh, India, revealed occurrence of 11 types of fungi. Of which, Aspergillus flavus, Aspergillus niger, and Aspergillus ochraceus were dominant causing severe decay of grapes with 58%, 52%, and 67% incidence, respectively. On screening of 15 essential oils at 0.33 μL/mL, Cymbopogon citratus oil caused 100% mycelial inhibition against aforesaid dominant fungi. Oil was fungistatic at 0.29 μL/mL and exhibited broad fungitoxicity against other fruit rotting fungi associated with collected samples. C. citratus oil completely inhibited the growth and mycotoxin (AFB1 and OTA) secretion of the aflatoxigenic and ochratoxigenic strains of A. flavus, A. niger, and A. ochraceus at 0.8 μL/mL. E-Citral (52.9%) and Z-Citral (39.38%) were the major components of C. citratus oil during gas chromatography and gas chromatography-mass spectrometry analysis. Application of 200 and 300 μL of C. citratus oil on 1 kg of stored grapes showed enhancement of shelf life up to 10 d. The oil did not exhibit any phytotoxic effect on fruits. These results confirm that C. citratus oil could be a natural alternative to commercial fungicide for control of fruit rotting fungi of stored grapes. © 2014 Institute of Food Technologists®

  14. Neurobehavioral effect of essential oil of Cymbopogon citratus in mice.

    Science.gov (United States)

    Blanco, M M; Costa, C A R A; Freire, A O; Santos, J G; Costa, M

    2009-03-01

    Tea obtained from leaves of Cymbopogon citratus (DC) Stapf is used for its anxiolytic, hypnotic and anticonvulsant properties in Brazilian folk medicine. Essential oil (EO) from fresh leaves was obtained by hydrodistillation and orally administered to Swiss male mice 30 min before experimental procedures. EO at 0.5 or 1.0 g/kg was evaluated for sedative/hypnotic activity through pentobarbital sleeping time, anxiolytic activity by elevated plus maze and light/dark box procedures and anticonvulsant activity through seizures induced by pentylenetetrazole and maximal electroshock. EO was effective in increasing the sleeping time, the percentage of entries and time spent in the open arms of the elevated plus maze as well as the time spent in the light compartment of light/dark box. In addition, EO delayed clonic seizures induced by pentylenetetrazole and blocked tonic extensions induced by maximal electroshock, indicating the elevation of the seizure threshold and/or blockage of seizures spread. These effects were observed in the absence of motor impairment evaluated on the rotarod and open field test. Our results are in accord with the ethnopharmacological use of Cymbopogon citratus, and after complementary toxicological studies it can support investigations assessing their use as anxiolytic, sedative or anticonvulsive agent.

  15. Inactivation of Escherichia coli, Listeria monocytogenes, and Salmonella Enteritidis by Cymbopogon citratus D.C. Stapf. Essential Oil in Pineapple Juice.

    Science.gov (United States)

    Leite, Caroline Junqueira Barcellos; de Sousa, Jossana Pereira; Medeiros, José Alberto da Costa; da Conceição, Maria Lúcia; dos Santos Falcão-Silva, Vivyanne; de Souza, Evandro Leite

    2016-02-01

    In the present study, the efficacy of Cymbopogon citratus D.C. Stapf. essential oil (CCEO) to provoke a 5-log CFU/ml (5-log) inactivation in a mixed composite of Escherichia coli, Listeria monocytogenes, and Salmonella enterica serovar Enteritidis in pineapple (Ananas comosus (L.) Merril) juice (4°C) was assessed. Moreover, the effects of CCEO on the physicochemical and sensory quality parameters of pineapple juice were evaluated. The MIC of CCEO was 5 μl/ml against the composite mix examined. For L. monocytogenes and E. coli inoculated in juice containing CCEO (5, 2.5, and 1.25 μl/ml), a ≥5-log reduction was detected after 15 min of exposure. This same result was obtained for Salmonella Enteritidis incubated alone in pineapple juice containing CCEO at 5 and 2.5 μl/ml. Overall, Salmonella Enteritidis was the most tolerant and L. monocytogenes was the most sensitive to CCEO. The physicochemical properties (pH, titratable acidic [citric acid per 100 g], and soluble solids) of pineapple juice containing CCEO (2.5 and 1.25 μl/ml) were maintained. Juice containing CCEO (2.5 and 1.25 μl/ml) exhibited similar scores for odor, appearance, and viscosity compared with juice without CCEO. However, unsatisfactory changes in taste and aftertaste were observed in juices containing CCEO. These results suggest that CCEO could be used as an alternative antimicrobial compound to ensure the safety of pineapple juice, although CCEO at the tested concentrations negatively impacted its taste. Therefore, further studies are needed to determine the balance between microbial safety and taste acceptability of pineapple juice containing CCEO.

  16. Chemical composition and cardiovascular effects induced by the essential oil of Cymbopogon citratus DC. Stapf, Poaceae, in rats Composição química e efeitos cardiovasculares do óleo essencial de Cymbopogon citratus DC. Stapf, Poaceae, em ratos

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    Flávia V. Moreira

    2010-12-01

    Full Text Available Cymbopogon citratus DC. Stapf, Poaceae, is used in the folk medicine for hypertension treatment. This work investigated the chemical composition and cardiovascular effects in rats of C. citratus essential oil (EOCC. A phytochemical screening demonstrated the presence of eight constituents, being geranial the major compound (43.08%. In rats, EOCC (1, 5, 10, and 20 mg/kg, i.v. induced transient hypotension and bradycardia that were attenuated by atropine and sodium thiopental, but not by L-NAME or indomethacin. In rings of rat superior mesenteric artery pre-contracted with phenylephrine, EOCC (1 to 3000 µg/mL induced relaxation that was not affected after removal of the endothelium, after TEA or in rings pre-contracted with KCl (80 mM. Furthermore, EOCC (1000 µg/mL was not able to induce additional effect on maximal relaxation of nifedipine (10 µM. In conclusions, EOCC induces hypotension, possibly by reduction in vascular resistance caused by inhibition of the Ca2+ influx, and bradycardia probably due to an activation of cardiac muscarinic receptors.C. citratus é utilizada na medicina popular para tratar hipertensão. Este trabalho investigou a composição química e os efeitos cardiovasculares do óleo essencial do C. citratus (OECC. Foram identificados oito constituintes no OECC, sendo geranial o majoritário (43,08%. Em ratos, o OECC (1, 5, 10 e 20 mg/kg, i.v. induziu hipotensão e bradicardia que foram atenuadas pela atropina e tiopental sódico, mas não por L-NAME ou indometacina. Em anéis de artéria mesentérica de ratos pré-contraídos com fenilefrina, o OECC (1 a 3000 µg/mL induziu relaxamento que não foi afetado após remoção do endotélio, após TEA ou em anéis pré-contraídos com KCl (80 mM. Além disso, o OECC (1000 µg/mL não induziu efeito adicional sobre o relaxamento máximo da nifedipina (10 µM. Em conclusão, o OECC induz hipotensão possivelmente devido à redução da resistência vascular que pode ser causada

  17. AVALIAÇÃO DA ATIVIDADE ANTIBACTERIANA E MODULADORA DE AMINOGLICOSÍDEOS DO ÓLEO ESSENCIAL DE Cymbopogon citratus (DC. Stapf

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    Bruno F. F. LUCENA

    2015-01-01

    Full Text Available Varios trabajos están demostrando la importancia del estudio de productos naturales como una fuente alternativa para nuevos antimicrobianos o que puedan mejorar los ya existentes. En este contexto, el objetivo de este trabajo fue investigar la actividad antibacteriana y las posibles interacciones entre el aceite esencial de Cymbopogon citratus aminoglucósido combinado frente de linajes y patrones de S. aureus multirresistente, E. coli y P. aeruginosa provenientes de aislamientos clínicos. Se realizó una prueba de microdilución para verificar la actividad antibacteriana y posibles interacciones entre el producto natural y antibióticos, usando una concentración sub-inibitória. A través de los resultados se observan interferencia sinérgica de los aminoglucósidos cuando se asocian con el aceite esencial en una concentración de CIM/8, con reducción de CIMs de hasta cuatro puntos contra las cepas de S. aureus 358, E. coli 27 y P. aeruginosa 143. Pero no se observó ninguna actividad modificadora contra P. aeruginosa 78 y P. aeruginosa 91. A través de los resultados se puede concluir que el aceite esencial de Cymbopogon citratus puede ser una fuente alternativa de productos naturales con actividad antibacteriana.

  18. Effects of essential oils from Cymbopogon citratus (DC) Stapf., Lippia sidoides Cham., and Ocimum gratissimum L. on growth and ultrastructure of Leishmania chagasi promastigotes.

    Science.gov (United States)

    Oliveira, Valéria C S; Moura, Daniela M S; Lopes, José A D; de Andrade, Paulo P; da Silva, Nicácio H; Figueiredo, Regina C B Q

    2009-04-01

    The current therapy for leishmaniasis, which affects annually about 2 million people, is far from satisfactory. All available drugs require parenteral administration and are potentially toxic. Plant essential oils have been traditionally used in folk medicine and appear as valuable alternative source for chemotherapeutic compounds. In this study, we demonstrated the effect of essential oils from Cymbopogon citratus, Lippia sidoides, and Ocimum gratissimum on growth and ultrastructure of Leishmania chagasi promastigote forms. Steam distillation was used to isolate the essential oils, and their constituents were characterized by gas chromatography coupled to mass spectrometry and nuclear magnetic resonance. All essential oils showed in vitro inhibitory action on L. chagasi promastigotes growth in a dose-dependent way, with IC(50)/72 h of 45, 89, and 75 microg/mL for C. citratus, L. sidoides, and O. gratissimum, respectively. Drastic morphological alterations were observed in all essential oil-treated parasites, including cell swelling, accumulation of lipid droplets in the cytoplasm, and increase of acidocalcisome volume. Furthermore, aberrant-shaped cells with multi-septate body were observed by scanning electron microscopy, suggesting an additional effect on cytokinesis. Taken together, our data show that these essential oils affect the parasite viability being the C. citratus essential oil the most effective against L. chagasi.

  19. Exploring the antimalarial potential of whole Cymbopogon citratus plant therapy.

    Science.gov (United States)

    Chukwuocha, Uchechukwu M; Fernández-Rivera, Omar; Legorreta-Herrera, Martha

    2016-12-04

    Cymbopogon citratus (lemon grass) has been used in traditional medicine as an herbal infusion to treat fever and malaria. Generally, whole plant extracts possess higher biological activity than purified compounds. However, the antimalarial activity of the whole C. citratus plant has not been experimentally tested. To evaluate the antimalarial activity of an herbal infusion and the whole Cymbopogon citratus plant in two experimental models of malaria. The plant was dried for 10 days at room temperature and was then milled and passed through brass sieves to obtain a powder, which was administered to CBA/Ca mice with a patent Plasmodium chabaudi AS or P. berghei ANKA infection. We analysed the effects of two different doses (1600 and 3200mg/kg) compared with those of the herbal infusion and chloroquine, used as a positive control. We also assessed the prophylactic antimalarial activities of the whole C. citratus plant and the combination of the whole plant and chloroquine. The C. citratus whole plant exhibited prolonged antimalarial activity against both P. chabaudi AS and P. berghei ANKA. The low dose of the whole C. citratus plant displayed higher antimalarial activity than the high dose against P. berghei ANKA. As a prophylactic treatment, the whole plant exhibited higher antimalarial activity than either the herbal infusion or chloroquine. In addition, the combination of the whole C. citratus plant and chloroquine displayed higher activity than chloroquine alone against P. berghei ANKA patent infection. We demonstrated the antimalarial activity of the whole C. citratus plant in two experimental models. The whole C. citratus plant elicited higher anti-malarial activity than the herbal infusion or chloroquine when used as a prophylactic treatment. The antimalarial activity of the whole C. citratus plant supports continued efforts towards developing whole plant therapies for the management of malaria and other infectious diseases prevalent in resource

  20. Variação dos teores de constituintes voláteis de Cymbopogon citratus (DC Staf, Poaceae, coletados em diferentes regiões do Estado de São Paulo

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    Marcos R. Furlan

    2010-10-01

    Full Text Available O óleo essencial extraído de Cymbopogon citratus (DC Staf, Poaceae, é rico em citral sendo amplamente empregado na indústria química e farmacêutica. Os objetivos desse estudo foram avaliar o conteúdo de citral entre populações de C. citratus coletados em duas regiões diferentes (Ibiúna e Pindamonhangaba, Estado de São Paulo. O óleo essencial extraído de uma população cultivada em Pindamonhangaba-SP apresentou uma concentração alta de citral (aproximadamente 96,0%, enquanto que o óleo extraído da população de Ibiúna-SP apresentou, além de citral, proporções elevadas de outro monoterpeno, o geraniol. Adicionalmente, os óleos essenciais obtidos desta população de C. citratus foram extraídos e analisados ao longo de 24 h (a cada 3 h, sendo que o teor de citral foi maior no período da noite, o que mostra a importância de estudos que avaliam as diferenças químicas associadas às mudanças circadianas. Os componentes dos óleos essenciais foram identificados por RMN de 13C, CG/EM e CG através do índice de Kovats.

  1. Sugarcane Molasse and Whey as Additives in the Silage of Lemongrass (Cymbopogon citratus [DC.] Stapf Leaves Melaza de Caña de Azúcar y Suero de Leche como Aditivos en el Ensilaje de Hojas de Zacate de Limón (Cymbopogon citratus [DC.] Stapf

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    Lucía María Cristina Ventura-Canseco

    2012-03-01

    Full Text Available After extraction of essential oil from lemongrass (Cymbopogon citratus [DC.] Stapf leaves by steam distillation (heat treatment, large amounts of organic wastes are obtained. This by-product could easily be used as animal feed. The potential of sugarcane molasse and whey as additives to ensile lemongrass leaves was investigated. The vegetative material was obtained after essential oils were extracted from lemongrass leaves with steam distillation. Lemongrass leaves were chopped, mixed with sugarcane molasse and whey, placed in cylindrical plastic containers, hermetically closed. The experimental design for pH optimization was a response surface 3-level factorial design 3² with three replicates. Sugarcane molasse at 5, 10 and 15% (w/w and whey at 20, 25 and 30% (w/w were used. The pH of the silage decreased significantly in each treatment, but it was faster when sugarcane molasse was added. The lactic acid concentration was 2.8 g kg-1 DM in silage amended with 15% molasse plus 25% whey and was higher than in silage supplemented with commercial additive after 15 d. In conclusion, it was shown that lemongrass leaves obtained as by product after extracting essential oils can be effectively ensiled with whey and sugarcane molasse as additives inducing a faster production of lactic acid.Después de la extracción del aceite esencial de zacate limón (Cymbopogon citratus [DC.] Stapf por destilación con vapor (tratamiento térmico se obtiene un residuo. Este residuo podría ser utilizado para alimentación animal. El potencial de la melaza de caña y suero de leche como aditivos para ensilar hojas de zacate limón fue investigado. El material vegetal se obtuvo después que los aceites esenciales se extrajeron de las hojas de zacate limón usando destilación con vapor. Las hojas de zacate limón se picaron, mezclaron con melaza de caña y suero de leche y se colocaron en recipientes cilíndricos de plástico y se cerraron herméticamente. El dise

  2. In vitro cytotoxic activity of Cymbopogon citratus L. and Cymbopogon nardus L. essential oils from Togo

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    Koffi Koba; Komla Sanda; Catherine Guyon; Christine Raynaud; Jean-Pierre Chaumont; Laurence Nicod

    2009-01-01

    The leaf essential oils of Cymbopogon citratus L. and Cymbopogon nardus L. (Poaceae) from Togo were steam-distilled, analyzed for percentage composition and investigated in vitro for their potential cytotoxic activity on human epidermic cell line HaCat. The percentage composition showed that the main constituents of essential oils samples were respectively geranial (45.2%), neral (32.4%) and myrc¨ne (10.2%) for C. citratus essential oil and citronellal (35.5%), geraniol (27.9%) and citronello...

  3. Polysaccharides from Cymbopogon citratus with antitumor and immunomodulatory activity.

    Science.gov (United States)

    Bao, Xiao-Li; Yuan, Hui-Hui; Wang, Cheng-Zhong; Fan, Wei; Lan, Min-Bo

    2015-01-01

    Abstract Context: Most of the present studies on the antitumor efficiency of Cymbopogon citratus (DC.) Stapf (Gramineae) are limited to its low-mass compounds, and little information about the antitumor activity of polysaccharides from this plant is available. This study focused on the potential antitumor and immunomodulatory activities of polysaccharides (CCPS) from C. citratus. CCPS was isolated using the water extraction-ethanol precipitation method. The sarcoma 180 (S180) cells-inoculated mice were intraperitoneally administrated with CCPS (30-200 mg/kg/d) for seven consecutive days. The effects of CCPS on tumor growth, thymus and spleen weights, splenocyte proliferation, and cytokine secretion in the tumor-bearing mice were measured. The cytotoxicity of CCPS (50-800 μg/mL) towards S180 cells was also studied. CCPS significantly inhibited the growth of the transplanted S180 tumors, with the inhibition rates ranging from 14.8 to 37.8%. Simultaneously, CCPS dose-dependently improved the immunity of the tumor-bearing mice. With the highest dose of 200 mg/kg/d, the thymus and spleen indices were increased by 21.9 and 91.9%, respectively; ConA- and LSP-induced splenocyte proliferations were increased by 32.7 and 35.3%, respectively. The secretions of interleukin 2 (IL-2), interleukin 6 (IL-6), interleukin 2 (IL-12), and tumor necrosis factor-α (TNF-α) were increased by 103.2, 40.2, 23.6, and 26.3%, respectively. Nevertheless, almost no toxicity of CCPS towards S180 cells was observed, with the maximal inhibition rate less than 15% at the CCPS concentration of 800 μg/mL. CCPS exhibited antitumor activity in vivo, and this activity might be achieved by immunoenhancement rather than direct cytotoxicity.

  4. [A new lanostane-type triterpenoid from Cymbopogon citratus].

    Science.gov (United States)

    Zhang, Meng-Meng; Sun, Li-Li; Li, Cheng; Gao, Wan; Yang, Jian-Bo; Wang, Ai-Guo; Su, Ya-Lun; Ji, Teng-Fei

    2014-05-01

    To study the chemical constituents of Cymbopogon citratus, isolation and purification of constituents were carried out on silica gel, Sephadex LH-20 and prepatative HPLC. The structures of the compounds were identified by physicchemical properties and spectral data analysis. Eight compounds were isolated and identified as 3beta-methoxy lanosta-9(11)-en-27-ol (1), 3beta-hydroxylanosta-9 (11)-en (2), (24S) -3beta-methoxylanosta-9(11), 25-dien-24-ol (3), 8-hydroxyl-neo-menthol (4), (2E)-3,7-dimethyl-2,7-octadiene-1, 6-diol (5), (+)-citronellol (6), 7-hydroxymenthol (7) and ethyl nonadecanoate(8). Compounds 1 is a new one. Compounds 2-3 are obtained from C. citratus for the first time.

  5. In vitro cytotoxic activity of Cymbopogon citratus L. and Cymbopogon nardus L. essential oils from Togo

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    Koffi Koba

    2009-06-01

    Full Text Available The leaf essential oils of Cymbopogon citratus L. and Cymbopogon nardus L.(Poaceae from Togo were steam-distilled, analyzed for percentage composition and investigated in vitro for their potential cytotoxic activity on human epidermic cell line HaCat. The percentage composition showed that the main constituents of essential oils samples were respectively geranial (45.2%, neral(32.4% and myrcène (10.2% for C. citratus essential oil and citronellal (35.5%, geraniol (27.9% and citronellol (10.7% for that of C. nardus. The in vitro cytotoxicity bioassays on human epidermic cell line HaCaT revealed that the toxicityof the essential oil from C. citratus (IC50: 150 μL.mL-1 was higher than that of the essential oil from C. nardus (IC50: 450 μL.mL-1. Pure commercial neral, geranial, and citronellal standards showed respectively the following IC50 values: 100, 250 and 300 μL.mL-1. Conversely, pure citronellol standard appeared almost non-toxic (IC50>1000 μL.mL-1, proving the major role played in synergyby neral and geranial in the overall toxicity showed by the citratus oil sample tested in this work.

  6. Treatment of pityriasis versicolor with topical application of essential oil of Cymbopogon citratus (DC Stapf - therapeutic pilot study Tratamento de pitiríase versicolor com aplicação tópica do óleo essencial de Cymbopogon citratus (DC Stapf - estudo terapêutico piloto

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    Egberto Santos Carmo

    2013-06-01

    Full Text Available BACKGROUND: Pityriasis versicolor is a fungal infection caused by Malassezia spp. that has frequent relapses. OBJECTIVES: The main objective of this research was to perform phase I and II clinical studies, using formulations containing essential oil of Cymbopogon citratus in patients with pityriasis versicolor. METHODS: Phase I study included twenty volunteers to ascertain the safety of the formulations. In phase II, 47 volunteers randomly received essential oil formulations at 1.25 μL/mL concentration, for forty days. The shampoo should be applied three times a week and the cream twice a day. A control group in phase II, consisting of 29 volunteers, received the same formulations but with 2% ketoconazole as the active ingredient. RESULTS: No significant adverse events were observed in volunteers during Phase I. In Phase II, 30 (63.83% volunteers using essential oil and 18 (62.07% using ketoconazole remained until the end of the study. We observed a predominance of lesions in disseminated form, with M. sympodialis detected as the predominant agent identified in cultures. After 40 days of treatment, the rate of mycological cure was 60% (p FUNDAMENTOS: Pitiríase versicolor é uma micose causada pela Malassezia spp., e que apresenta frequentes recidivas. OBJETIVOS: Este trabalho objetivou realizar estudos clínicos de fase I e II, para essa patologia, com óleo essencial de Cymbopogon citratus. MÉTODOS: Na fase I, participaram vinte voluntários para averiguar a segurança das formulações. Na fase II, 47 voluntários receberam as formulações do óleo essencial a 1,25 μL/mL, as quais deveriam ser utilizadas por quarenta dias, sendo o xampu três vezes por semana e o creme duas vezes ao dia. Um grupo controle na fase II, constituído por 29 voluntários recebeu as mesmas formulações, com cetoconazol a 2%. RESULTADOS: Verificada a segurança das formulações com a finalização da fase I, onde nenhuma reação adversa significativa foi

  7. Bioactivity against Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) of Cymbopogon citratus and Eucalyptus citriodora essential oils grown in Colombia.

    Science.gov (United States)

    Olivero-Verbel, Jesús; Nerio, Luz S; Stashenko, Elena E

    2010-06-01

    Essential oils isolated from Cymbopogon citratus (DC) Stapf. and Eucalyptus citriodora Hook grown in Colombia were analysed by gas chromatography-mass spectrometry (GC-MS) and tested for repellent activity and contact toxicity against Tribolium castaneum (Herbst.) (Coleoptera: Tenebrionidae). The main components of C. citratus oil were geranial (34.4%), neral (28.4%) and geraniol (11.5%), whereas those of E. citriodora were citronellal (40%), isopulegol (14.6%) and citronellol (13%). The mean repellent doses after 4 h exposure were 0.021 and 0.084 mL L(-1) for C. citratus and E. citriodora oils respectively-values lower than that observed for the commercial product IR3535 (0.686 mL L(-1)). These studies showed the composition and repellent activity of essential oils of C. citratus and E. citriodora, suggesting that these are potential candidates as insect repellents.

  8. Evaluación de la actividad antibacteriana in vitro del aceite esencial de hierba luisa (cymbopogon citratus (dc) stapf), poaceae en una formulación cosmética con finalidad antiacneíca.

    OpenAIRE

    Meza Angos, Katherine Lourdes; Vargas Duque, Gabriela Geoconda

    2013-01-01

    The present research had as objectives to evaluate the in vitro antibacterial activity of the essential oil of Lemongrass (Cymbopogon citratus) against Propionibacterium acnes, bacteria that causes acne, to make a lotion and to evaluate the effectiveness in vitro and in vivo of the lotion formulated from this oil. The essential oil obtained from the leaves of the selected species, using a hydrodistillation system with steam entrainment; with the oil obtained miscibility tests were performe...

  9. Anthelmintic activity of Cymbopogon citratus against Haemonchus contortus.

    Science.gov (United States)

    Macedo, Iara Tersia Freitas; Oliveira, Lorena Mayana Beserra de; Ribeiro, Wesley Lyeverton Correia; Santos, Jessica Maria Leite dos; Silva, Kaline das Chagas; Araújo Filho, José Vilemar de; Camurça-Vasconcelos, Ana Lourdes Fernandes; Bevilaqua, Claudia Maria Leal

    2015-01-01

    Parasitic nematodes are of major economic importance in livestock. An alternative for the control of parasites is phytotherapy. This study evaluated the efficacy of Cymbopogon citratus decoction (CcD), C. citratus essential oil (CcEo) and citral against Haemonchus contortus using in vitro egg hatch test (EHT) and larval development test (LDT) and an in vivo test using a Meriones unguiculatus (gerbil) model. The effect of 800 mg/kg CcEo was evaluated in gerbils that had been artificially infected with 5,000 third-stage H. contortus larvae. The effective concentrations required to inhibit 50% (EC50) of egg hatching were 0.46, 0.14 and 0.13 mg/mL for CcD, CcEo and citral, respectively. The EC50 values in the LDT were 5.04, 1.92 and 1.37 mg/mL for CcD, CcEo and citral, respectively. H. contortus population in the group treated with C. citratus essential oil was reduced by 38.5% (Pcitratus essential oil to control of H. contortus parasite of small ruminant.

  10. Data showing chemical compositions of the essential oils of the leaves of Cymbopogon citratus obtained by varying pH of the extraction medium

    OpenAIRE

    Ajayi, E.O.; Sadimenko, A.P.; Afolayan, A.J.

    2016-01-01

    This article describes the various chemical components as obtained from the oils in the leaves of Cymbopogon citratus using hydrodistillation and solvent-free microwave extraction methods. Furthermore, extractions of the oils were also carried out with a slight in pH variation and compared, “GC–MS evaluation of C. citratus (DC) Stapf oil obtained using modified hydrodistillation and microwave extraction methods” (Ajayi et al., 2016 [1]). The current article contains one table exhibiting a lis...

  11. Cymbopogon citratus Protects against the Renal Injury Induced by Toxic Doses of Aminoglycosides in Rabbits

    OpenAIRE

    Ullah, N.; Khan, M A; Khan, T.; Ahmad, W

    2013-01-01

    Renal injury is the most common side-effect of aminoglycosides. These antimicrobial drugs are particularly effective against Gram-negative microorganisms. The present study was conducted to investigate the renal protective activity of Cymbopogon citratus in gentamicin-induced nephrotoxicity. Male rabbits were divided into four groups (n=6) including group 1 (0.9% saline treated), group 2 (80 mg/kg/day gentamicin-treated), group 3 (200 mg/kg/day Cymbopogon citratus treated) and group 4 (80 mg/...

  12. Effect of Cymbopogon citratus and Citral on Vascular Smooth Muscle of the Isolated Thoracic Rat Aorta

    OpenAIRE

    Devi, R. Chitra; Sim, S. M.; Ismail, R.

    2012-01-01

    Cymbopogon citratus has been shown to have antioxidant, antimicrobial, antispasmodic and chemo-protective properties. Citral, is the major constituent of C. citratus. This study investigated the effects of methanolic extracts of leaves (LE), stems (SE), and roots (RE) of C. citratus and citral on vascular smooth muscle and explored their possible mechanisms of action. The experiment was conducted using isolated tissue preparations, where citral, LE, SE, and RE were added separately into a tis...

  13. OPTIMASI KOMPOSISI TWEEN 80 DAN SPAN 80 SEBAGAI EMULGATOR DALAM REPELAN MINYAK ATSIRI DAUN SERE (Cymbopogon citratus (DC Stapf TERHADAP NYAMUK Aedes aegypti BETINA PADA BASIS VANISHING CREAM DENGAN METODE SIMPLEX LATTICE DESIGN

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    Endah Nurlaela

    2012-05-01

    Full Text Available The disease of Dengue hemorrhagic fever (DHF is caused by the bite of female Aedes aegypti mosquito. Cream of repelan sere leaf essential oils can be used to prevent mosquito bites. The cream of volatile oil sere (Cymbopogon citratus (DC Stapf required emulsifier to maintain the stability of cream. Tween 80 and Span 80 is a widely used emulsifier in a cream formula. Aims of this study is to determine the optimum composition of Tween 80 and Span 80 as emulsifier in a cream repelan of sere leaf essential oils in the basis Vanishing Cream with Simplex Lattice Design methode. Three Formula cream is designed based on the Simplex Lattice Design methode with a ratio of Tween 80: Span 80 as follows: FI (100%-0%, F II (50%-50%, F III (0%-100%. Cream was then tested repelan activity and physical properties that include spreadibility, adhesivity and irritation. Data of physical properties and repellant activity was calculate to get the optimum formula. The validity of optimization methods was evaluated by comparing experimental results with predicted results in optimum cream formula with t test at 95% level of confidence. The results of study showed that the optimum composition of Tween 80: Span 80 was 60%:40%. Cream with optimum emulsifier composition was predicted has spreadibility 29.24 cm2; adhesivity 3.512 seconds; irritation 0.608; power repelan 41.469 minutes. T test results showed no significant differences between the experimental results and predicted results (p <0.05.

  14. AVALIAÇÃO DE POTENCIAL DE ERVAS MEDICINAIS: CAPIM-LIMÃO (Cymbopogon citratus D.C., CHÁ VERDE (Camellia sinensis L. E HIBISCO (Hibiscus sabdariffa L. PARA OBTENÇÃO DE CHÁS SOLÚVEIS

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    Uellison dos Santos

    2014-12-01

    Full Text Available Este trabalho foi realizado com o objetivo de avaliar características físico-químicas de extrato aquoso e liofilizado de capim-limão (Cymbopogon citratus D.C., chá verde (Camellia sinensis L. e hibisco (Hibiscus sabdariffa L., foram realizadas analises em triplicata  de teor de sólidos solúveis, acidez titulável, pH, atividade de água e solubilidade em água. Os resultados do extrato aquoso e liofilizado para o capim limão apresentaram (SST variando de 3,0333 a 38,3066, valores de pH variando de 5,08 e 6,32 além de atividade de água características para os estados em que os extratos se encontravam, para o resultado do chá verde obtivemos teor de (SST variando de 2,81 a 45,52, pH entre 5,04 e 6,28 além de atividade de água característica. Os extratos de hibisco também apresentaram resultados satisfatórios com teor (SST entre 3,28 e 34,16, pH de 2,34 e 3,16 e atividade de água característica.  Os resultados obtidos revelaram a importância do processo de liofilização nas amostras, uma vez que houve um aumento da qualidade dos chás sem que houvesse danos na sua qualidade sensorial.

  15. Antifungal activity of Cymbopogon citratus against Colletotrichum gloesporioides

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    Alexander Francisco Pérez Cordero

    2017-04-01

    Full Text Available The objective of this research was to evaluate in vitro the inhibitory activity of essential oils from fresh leaves of Cymbopogon citratus (lemongrass against Colletotrichum gloeosporioides in yam. The research was conducted in the department of Sucre, Colombia. The essential oils of C. citratus were collected in the municipalities of Sincelejo, La Union and Sampues, in September and October 2015. The essential oil was extract from fresh leaves using the microwave-assisted hydrodistillation. Concentrations of 5000, 8000 and 10 000 ppm of each essential oil were prepared. An absolute control, a positive control (benomyl 1 g/l and a negative control was used. An inhibitory activity was obtained by using the direct seeding on surface of the potato-dextrose-agar method and it was expressed as percentage of inhibition rate. The chemical characterization of essential oils was performed by gas chromatography coupled to mass spectrometry. The highest percentages of antifungal index were observed in the lemongrass from Sincelejo at concentrations of 5000, 8000 and 10 000 ppm, after in La Union at 8000 and 10 000 ppm, and finally at Sampues at 10 000 ppm, with a value of 97.77%; the effect was similar to the positive control with benomyl 1 g/l. Citral was the main constituent of the essential oils extracted. The essential oils obtained from the three municipalities showed antifungal activity against C. gloeosporioides.

  16. Gastroprotective effect of Cymbopogon citratus infusion on acute ethanol-induced gastric lesions in rats.

    Science.gov (United States)

    Sagradas, Joana; Costa, Gustavo; Figueirinha, Artur; Castel-Branco, Maria Margarida; Silvério Cabrita, António Manuel; Figueiredo, Isabel Vitória; Batista, Maria Teresa

    2015-09-15

    Treatment of gastric ulcers with medicinal plants is quite common in traditional medicine worldwide. Cymbopogon citratus (DC) Stapf. leaves infusion has been used in folk medicine of many tropical and subtropical regions to treat gastric disturbances. The aim of this study was to assess the potential gastroprotective activity of an essential oil-free infusion from C. citratus leaves in acute gastric lesions induced by ethanol in rat. The study was performed on adult male Wistar rats (234.0±22.7g) fasted for 24h but with free access to water. The extract was given orally before (prevention) or after (treatment) intragastric administration of absolute ethanol. Effects of dose (28 or 56mg/kg of body weight) and time of contact of the extract with gastric mucosa (1 or 2h) were also assessed. Animals were sacrificed, being the stomachs removed and the lesions were assessed by macroscopic observation and histopathology. C. citratus extract, given orally before or after ethanol, significantly (Pcitratus extract on experimental gastric lesions induced by ethanol, contributing for the pharmacological validation of its traditional use. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. Scientific validation of synergistic antioxidant effects in commercialised mixtures of Cymbopogon citratus and Pterospartum tridentatum or Gomphrena globosa for infusions preparation.

    Science.gov (United States)

    Roriz, Custódio Lobo; Barros, Lillian; Carvalho, Ana Maria; Santos-Buelga, Celestino; Ferreira, Isabel C F R

    2015-10-15

    Pterospartum tridentatum (L.) Willk., Gomphrena globosa L. and Cymbopogon citratus (DC) Stapf. are examples of medicinal plants with antioxidant properties on their own, but that can be improved when mixed. In the present work, the antioxidant activity and phenolic compounds were determined in the infusions prepared from the individual plants, and from mixtures of these plants in different proportions. P. tridentatum > C. citratus > G. globosa was the order observed for antioxidant efficacy, which can be related to their different composition in phenolic compounds. Synergism was the main effect observed among the tested mixtures, mainly for the infusions prepared from the plants in proportion 40%:60% (either P. tridentatum and C. citratus; or G. globosa and C. citratus). The infusion obtained with 40% of P. tridentatum and 60% of C. citratus gave the highest antioxidant properties. The present study validates the commercialisation of the studied plants combined in specific proportions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. In Vitro Mass Propagation of Cymbopogon citratus Stapf., a Medicinal Gramineae.

    Science.gov (United States)

    Quiala, Elisa; Barbón, Raúl; Capote, Alina; Pérez, Naivy; Jiménez, Elio

    2016-01-01

    Cymbopogon citratus (D.C.) Stapf. is a medicinal plant source of lemon grass oils with multiple uses in the pharmaceutical and food industry. Conventional propagation in semisolid culture medium has become a fast tool for mass propagation of lemon grass, but the production cost must be lower. A solution could be the application of in vitro propagation methods based on liquid culture advantages and automation. This chapter provides two efficient protocols for in vitro propagation via organogenesis and somatic embryogenesis of this medicinal plant. Firstly, we report the production of shoots using a temporary immersion system (TIS). Secondly, a protocol for somatic embryogenesis using semisolid culture for callus formation and multiplication, and liquid culture in a rotatory shaker and conventional bioreactors for the maintenance of embryogenic culture, is described. Well-developed plants can be achieved from both protocols. Here we provide a fast and efficient technology for mass propagation of this medicinal plant taking the advantage of liquid culture and automation.

  19. Lemon grass (Cymbopogon citratus (D.C) Stapf) polyphenols protect human umbilical vein endothelial cell (HUVECs) from oxidative damage induced by high glucose, hydrogen peroxide and oxidised low-density lipoprotein.

    Science.gov (United States)

    Campos, J; Schmeda-Hirschmann, G; Leiva, E; Guzmán, L; Orrego, R; Fernández, P; González, M; Radojkovic, C; Zuñiga, F A; Lamperti, L; Pastene, E; Aguayo, C

    2014-05-15

    The aromatic herb Cymbopogon citratus Stapf is widely used in tropical and subtropical countries in cooking, as a herbal tea, and in traditional medicine for hypertension and diabetes. Some of its properties have been associated with the in vitro antioxidant effect of polyphenols isolated from their aerial parts. However, little is known about C. citratus effects on endothelial cells oxidative injury. Using chromatographic procedures, a polyphenol-rich fraction was obtained from C. citratus (CCF) and their antioxidant properties were assessed by cooper-induced LDL oxidation assay. The main constituents of the active CCF, identified by high-performance liquid chromatography with diode-array detection and mass spectrometry (HPLC-DAD-MS), were chlorogenic acid, isoorientin and swertiajaponin. CCF 10 and 100 μg/ml diminishes reactive oxidative species (ROS) production in human umbilical vein endothelial cell (HUVECs), challenged with high D-glucose (60% inhibition), hydrogen peroxide (80% inhibition) or oxidised low-density lipoprotein (55% inhibition). CCF 10 or 100 μg/ml did not change nitric oxide (NO) production. However, CCF was able to inhibit vasoconstriction induced by the thromboxane A2 receptor agonist U46619, which suggest a NO-independent vasodilatador effect on blood vessels. Our results suggest that lemon grass antioxidant properties might prevent endothelial dysfunction associated to an oxidative imbalance promoted by different oxidative stimuli. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Scientific basis for the therapeutic use of Cymbopogon citratus, stapf (Lemon grass).

    Science.gov (United States)

    Shah, Gagan; Shri, Richa; Panchal, Vivek; Sharma, Narender; Singh, Bharpur; Mann, A S

    2011-01-01

    Cymbopogon citratus, Stapf (Lemon grass) is a widely used herb in tropical countries, especially in Southeast Asia. The essential oil of the plant is used in aromatherapy. The compounds identified in Cymbopogon citratus are mainly terpenes, alcohols, ketones, aldehyde and esters. Some of the reported phytoconstituents are essential oils that contain Citral α, Citral β, Nerol Geraniol, Citronellal, Terpinolene, Geranyl acetate, Myrecene and Terpinol Methylheptenone. The plant also contains reported phytoconstituents such as flavonoids and phenolic compounds, which consist of luteolin, isoorientin 2'-O-rhamnoside, quercetin, kaempferol and apiginin. Studies indicate that Cymbopogon citratus possesses various pharmacological activities such as anti-amoebic, antibacterial, antidiarrheal, antifilarial, antifungal and anti-inflammatory properties. Various other effects like antimalarial, antimutagenicity, antimycobacterial, antioxidants, hypoglycemic and neurobehaviorial have also been studied. These results are very encouraging and indicate that this herb should be studied more extensively to confirm these results and reveal other potential therapeutic effects.

  1. Biofilm inhibition by Cymbopogon citratus and Syzygium aromaticum essential oils in the strains of Candida albicans.

    Science.gov (United States)

    Khan, Mohd Sajjad Ahmad; Ahmad, Iqbal

    2012-03-27

    Oils of Cymbopogon citratus and Syzygium aromaticum have been used in traditional medicine to treat fungal infections of skin, mouth, urinary and vaginal tract in Asian countries particularly India and other developing countries. To evaluate essential oils of Cymbopogon citratus and Syzygium aromaticum for their anti-biofilm activity against strong biofilm forming strains of Candida albicans. XTT reduction assay, Time kill assays, light microscopy and scanning electron microscopy (SEM) were employed to determine the effect of test oils on the Candida albicans biofilms. Most of the Candida albicans strains tested displayed formation of moderate to strong biofilms. Preformed Candida biofilms showed ≥1024 times increased resistance to antifungal drugs, 2 times to Syzygium aromaticum, but no increased tolerance for Cymbopogon citratus. Test oils were more active against preformed biofilms compared to amphotericin B and fluconazole. At 0.5× MIC, Cymbopogon citratus followed by Syzygium aromaticum were most inhibitory against biofilm formation. Light and electron microscopic studies revealed the deformity of three dimensional structures of biofilms formed in the presence of sub-MICs of Cymbopogon citratus. The cell membranes appeared to be the target site of compounds in sessile cells as displayed by SEM observations. Our data had demonstrated promising in vitro anti-biofilm activity by Cymbopogon citratus and Syzygium aromaticum and confirm the ethnopharmacological use of these oils in muco-cutaneous Candida infections. Furthermore, it suggests exploitation of these oils as new anti-biofilm products to deal with the problem of drug-resistance and recurrent infection associated with biofilm mode of growth of Candida spp. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  2. Cymbopogon citratus Protects against the Renal Injury Induced by Toxic Doses of Aminoglycosides in Rabbits.

    Science.gov (United States)

    Ullah, N; Khan, M A; Khan, T; Ahmad, W

    2013-03-01

    Renal injury is the most common side-effect of aminoglycosides. These antimicrobial drugs are particularly effective against Gram-negative microorganisms. The present study was conducted to investigate the renal protective activity of Cymbopogon citratus in gentamicin-induced nephrotoxicity. Male rabbits were divided into four groups (n=6) including group 1 (0.9% saline treated), group 2 (80 mg/kg/day gentamicin-treated), group 3 (200 mg/kg/day Cymbopogon citratus treated) and group 4 (80 mg/kg/day gentamicin and 200 mg/kg/day Cymbopogon citratus treated). Biochemical kidney functioning parameters, urinary enzymes and histopathological examination were performed. The results of the present study showed that simultaneous administration of Cymbopogon citrates and gentamicin significantly protected alteration in body weight, blood urea nitrogen, serum creatinine, creatinine clearance, serum uric acid, serum electrolytes, urinary volume, urinary protein, urinary lactate dehydrogenase and urinary alkaline phosphatase induced by gentamicin. Histological examination of the kidney also suggested the same. It is concluded from the current study that co-administration of Cymbopogon citratus with gentamicin for 3 weeks successfully prevented renal damage associated with aminoglycosides.

  3. STUDIES ON MOSQUITO REPELLENT ACTIVITY OF CYMBOPOGON CITRATUS (LEMON GRASS) USING HUMAN VOLUNTEERS

    OpenAIRE

    Ukpong, Iniodu George; Ettah, Hannah Edim; Eshuong, Emmanuel Edet

    2016-01-01

    Background: Safety concerns over the use of chemical-based pesticides are provoking intense studies and application of bio-pesticides in disease control and agriculture. Aim: This qualitative study was aimed at testing the repellent efficacy; and suitability of Cymbopogon citratus (Lemongrass) for the development of natural product-based mosquito repellent. Method: Cymbopogon oil (75ml) was extracted from 200g of fresh Lemongrass leaves using Soxhlet method with n-Hexane as solvent. Human vol...

  4. Data showing chemical compositions of the essential oils of the leaves of Cymbopogon citratus obtained by varying pH of the extraction medium.

    Science.gov (United States)

    Ajayi, E O; Sadimenko, A P; Afolayan, A J

    2016-09-01

    This article describes the various chemical components as obtained from the oils in the leaves of Cymbopogon citratus using hydrodistillation and solvent-free microwave extraction methods. Furthermore, extractions of the oils were also carried out with a slight in pH variation and compared, "GC-MS evaluation of C. citratus (DC) Stapf oil obtained using modified hydrodistillation and microwave extraction methods" (Ajayi et al., 2016 [1]). The current article contains one table exhibiting a list of compounds in the four different methods of extraction. Comparative studies amongst the various methods of extraction are highlighted in the table.

  5. Influence of extraction methodologies on the analysis of five major volatile aromatic compounds of citronella grass (Cymbopogon nardus) and lemongrass (Cymbopogon citratus) grown in Thailand

    Science.gov (United States)

    Infusions of citronella grass (Cymbopogon nardus) and lemongrass (Cymbopogon citratus) have been commonly used in folk medicine in Thailand and other Asian countries. This study focuses on a systematic comparison of two extraction methods for major volatile aromatic compounds (VACs) of citronella g...

  6. Efeito alelopático de sabugueiro e capim-limão na germinação de picão-preto e soja = Allelophatic effect of Sambucus australis Cham. and Schltdl. and Cymbopogon citratus (DC Stapf. in the germination of Bidens pilosa L. and soybeans

    Directory of Open Access Journals (Sweden)

    Andréa Maria Teixeira Fortes

    2009-04-01

    Full Text Available As plantas invasoras são constantes e diminuem a produtividade das culturas por competirem por espaço, nutrientes e água. Dessa forma, os agricultores adotam, em grande escala, produtos químicos eficientes no controle da lavoura e com alta toxicidade ao meioambiente. Existem, no entanto, formas alternativas para o controle de invasoras, por meio de aleloquímicos presentes em algumas plantas, dentre elas, as medicinais. Este trabalho tem como objetivo analisar as propriedades alelopáticas dos extratos das plantas medicinais Cymbopogon citratus (DC Stapf. e Sambucus australis Cham. and Schltdl. em inibir a germinação de Bidens pilosa L., sem interferir na germinação de Glycine max L. Merrill. Os extratos foram obtidos triturandose 200 g de folhas com 1 L de água destilada. As sementes foram mantidas em B.O.D. à temperatura de 25°C, com fotoperíodo de 12h de luz. Nas condições em que foram realizados os experimentos, constatou-se que o extrato de capim-limão inibiu a germinação de picão-preto sem que este inibisse a germinação da soja, enquanto o extrato de sabugueiro inibiu a germinação de picão-preto e a germinação da soja. Assim, indica-se a utilização do capim-limão, como um herbicida natural para o picão-preto.Agriculture has been suffering adaptations throughout time, from hard hand labor to the most advanced sowing and harvesting techniques. Invasive plants are a constant, diminishing productivity by competing for space, nutrients, and water. Therefore, farmers have adopted, on alarge scale, the use of efficient synthetic chemicals, which are highly toxic to the environment, in order to control plant production. However, there are other alternative means to control those competitors: using allelochemicals present in some plants, such as medicinal ones. The objective of this paper is to analyze allelophatic properties of the medicinal plants Cymbopogon citratus (DC Stapf. and Sambucus australis Cham. and Schltdl

  7. Efficacy of essential oils of Cymbopogon citratus (D.C.) Stapf, Lippia multiflora Moldenke and hot water in the control of seed-borne fungi Phoma sorghina and their effects on Sorghum bicolor (L.) Moench seed germination and plants development in Burkina Faso

    OpenAIRE

    Schémaeza BONZI1; Irénée SOMDA; Paco SEREME; Adam, Toudou

    2013-01-01

    The effects of two essential oils (Cymbopogon citratus and Lippia multiflora) and varying durations of hot water at 50°C on seed-borne fungi Phoma sorghina on five varieties of sorghum were evaluated using morphological traits. The varieties were ICSV 1001, Sariaso 03, ICSV 1049, Kapelga and the local variety, 1341So07. The results indicate that hot water treatment and essential oil of C. citratus significantly reduced the infection level of P. sorghina compared to untreated seeds, seeds trea...

  8. Evaluation of the lemongrass plant (Cymbopogon citratus) extracted in different solvents for antioxidant and antibacterial activity against human pathogens

    OpenAIRE

    Balachandar Balakrishnan; Sadayan Paramasivam; Abimanan Arulkumar

    2014-01-01

    Objective: To test antibacterial and antioxidant activity of the lemongrass plant Cymbopogon citratus (C. citratus) leaves extracted serially by the solvents (chloroform, methanol and water). Methods: The plant leaves extracts were used for antibacterial activity on Bacillus subtilis, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Nocardia sp., Serratia sp., and Enterobacter aeruginosa microorganisms by the Kirby Bauer agar disc diffusion method. This study wa...

  9. Polyphenols from Cymbopogon citratus leaves as topical anti-inflammatory agents.

    Science.gov (United States)

    Costa, Gustavo; Ferreira, João Pinto; Vitorino, Carla; Pina, Maria Eugénia; Sousa, João José; Figueiredo, Isabel Vitória; Batista, Maria Teresa

    2016-02-03

    A variety of plant polyphenols have been reported to have anti-inflammatory, frequently associated with erythema, edema, hyperplasia, skin photoaging and photocarcinogenesis. Cymbopogon citratus (DC). Stapf (Poaceae) is a worldwide known medicinal plant, used in traditional medicine in inflammation-related conditions. In this work, the anti-inflammatory potential of C. citratus infusion (CcI) and its polyphenols as topical agents was evaluated in vivo. The plant extract was prepared and its fractioning led two polyphenol-rich fractions: flavonoids fraction (CcF) and tannins fraction (CcT). An oil/water emulsion was developed with each active (CcI, CcF+CcT and diclofenac), pH and texture having been evaluated. Release tests were further performed using static Franz diffusion cells and all collected samples were monitored by HPLC-PDA. In vivo topical anti-inflammatory activity evaluation was performed by the carrageenan-induced rat paw edema model. The texture analysis revealed statistically significant differences for all tested parameters to CcF+CcT, supporting its topical application. Release experiments lead to the detection of the phenolic compounds from each sample in the receptor medium and the six major flavonoids were quantified, by HPLC-PDA: carlinoside, isoorientin, cynaroside, luteolin 7-O-neohesperidoside, kurilesin A and cassiaoccidentalin B. The CcF+CcT formulation prompted to the higher release rate for all these flavonoids. CcI4%, CcI1% and CcF+CcT exhibited an edema reduction of 43.18, 29.55 and 59.09%, respectively. Our findings highlight that CcI, containing luteolin 7-O-neohesperidoside, cassiaoccidentalin B, carlinoside, cynaroside and tannins have a potential anti-inflammatory topical activity, suggesting their promising application in the treatment of skin inflammatory pathologies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. Manipulation of rumen ecology by dietary lemongrass (Cymbopogon citratus Stapf.) powder supplementation.

    Science.gov (United States)

    Wanapat, M; Cherdthong, A; Pakdee, P; Wanapat, S

    2008-12-01

    This experiment was conducted to investigate the effect of lemongrass [Cymbopogon citratus (DC.) Stapf.] powder (LGP) on rumen ecology, rumen microorganisms, and digestibility of nutrients. Four ruminally fistulated crossbred (Brahman native) beef cattle were randomly assigned according to a 4 x 4 Latin square design. The dietary treatments were LGP supplementation at 0, 100, 200, and 300 g/d with urea-treated rice straw (5%) fed to allow ad libitum intake. Digestibilities of DM, ether extract, and NDF were significantly different among treatments and were greatest at 100 g/d of supplementation. However, digestibility of CP was decreased with LGP supplementation (P 0.05). Total viable bacteria, amylolytic bacteria, and cellulolytic bacteria were significantly different among treatments and were greatest at 100 g/d of supplementation (4.7 x 10(9), 1.7 x 10(7), and 2.0 x 10(9) cfu/mL, respectively). Protozoal populations were significantly decreased by LGP supplementation. In addition, efficiency of rumen microbial N synthesis based on OM truly digested in the rumen was enriched by LGP supplementation, especially at 100 g/d (34.2 g of N/kg of OM truly digested in the rumen). Based on this study, it could be concluded that supplementation of LGP at 100 g/d improved digestibilities of nutrients, rumen microbial population, and microbial protein synthesis efficiency, thus improving rumen ecology in beef cattle.

  11. In vitro activity of the essential oil of Cymbopogon citratus and its major component (citral) on Leishmania amazonensis.

    Science.gov (United States)

    Santin, Marta Regina; dos Santos, Adriana Oliveira; Nakamura, Celso Vataru; Dias Filho, Benedito Prado; Ferreira, Izabel Cristina Piloto; Ueda-Nakamura, Tânia

    2009-11-01

    Leishmaniasis causes considerable mortality throughout the world, affecting more than 12 million people. Cymbopogon citratus (DC) Stapf, Family Poaceae, is a widely used herb in tropical countries and is also known as a source of ethnomedicines. In this study, the inhibitory effect and the morphological and ultrastructural alterations on Leishmania amazonensis by the essential oil (EO) of C. citratus and its main constituent, citral, were evaluated. The results showed that the antiproliferative activity of EO on promastigotes and axenic amastigotes, and intracellular amastigote forms of L. amazonensis was significantly better than citral, and indicated a dose-dependent effect. Neither compound showed a cytotoxic effect on macrophage strain J774G8. The promastigote forms of L. amazonensis underwent remarkable morphological and ultrastructural alterations compared with untreated cultures. These alterations were visible by light, scanning, and transmission electron microscopy of promastigotes treated with EO and citral at concentrations corresponding to the IC(50) (1.7 and 8.0 microg/ml) and IC(90) (3.2 and 25 microg/ml), respectively, after 72 h of incubation. This study revealed that citral-rich essential oil from C. citratus has promising antileishmanial properties, and is a good candidate for further research to develop a new anti-protozoan drug.

  12. Efficacité des huiles essentielles de Cymbopogon citratus et de ...

    African Journals Online (AJOL)

    Malgré son importance nutritionnelle et socio-économique, la conservation du lait frais de vache demeure toujours un problème crucial dans les grands systèmes post-collecte du lait. La présente étude vise donc à évaluer les propriétés antimicrobiennes des huiles essentielles extraites des feuilles de Cymbopogon citratus ...

  13. Effect of Cymbopogon citratus (lemon grass) spiced diet on the liver ...

    African Journals Online (AJOL)

    We studied the effect of Cymbopogon citratus (lemon grass) spiced diet on the serum and liver of albino rats. The spice was mixed in a graded concentration of 5.0, 10.0, and 15.0 g with normal rat ration, and fed to the rats twice daily for 7 days. A total of sixteen rats were group into four to represent the control and the ...

  14. Etude de l'activité antifongique d'extraits de Cymbopogon citratus ...

    African Journals Online (AJOL)

    A travers la méthode de la croissance mycélienne utilisée dans ce test, nous avions constaté que l'huile essentielle de Cymbopogon citratus à 400 ppm et 600 ppm a inhibé totalement la croissance mycélienne de Bipolaris oryzae et celle de Pyricularia oryzae à partir de 200 ppm. L'huile essentielle de Lippia multiflora a ...

  15. Effects of Cymbopogon citratus and Ferula assa-foetida extracts on glutamate-induced neurotoxicity.

    Science.gov (United States)

    Tayeboon, Ghazaleh S; Tavakoli, Fatemeh; Hassani, Shokoufeh; Khanavi, Mahnaz; Sabzevari, Omid; Ostad, S Nasser

    2013-10-01

    Many of CNS diseases can lead to a great quantity of release of glutamate and the extreme glutamate induces neuronal cell damage and death. Here, we wanted to investigate the effects of Cymbopogon citratus essential oil and Ferula assa-foetida extracts treatment on glutamate-induced cell damage in a primary culture of rat cerebellar granule neurons. Cerebellums were collected from 7-d rat brains and cerebellar granule neurons were obtained after 8-d culture. CGN cells were treated with C. citratus essential oil and F. assa-foetida extracts at concentration of 100 μg/ml before, after, and during exposure to 30 μM glutamate. The cellular viability was evaluated by 3-(4, 5-dimethytthiazol-2-yl)-2, 5-diphenyltetrazoliumbromide (MTT) staining. The flow cytometry assay was used to examine cell cycle and apoptosis. MTT assay showed a glutamate-induced reduction in cellular viability while treatment with C. citratus essential oil and F. assa-foetida extracts before, during, and after exposure to glutamate was increased. Flow cytometric analysis indicated that F. assa-foetida extracts treatment significantly (p citratus essential oil treatment compared to glutamate group, significantly (p citratus essential oil and F. assa-foetida extracts display neuroprotective effects in glutamate-induced neurotoxicity. These extracts exert antiapoptotic activity in cerebellar granule neurons due to cell cycle arrest in G0G1 phase, which explain the beneficial effects of C. citratus essential oil and F. assa-foetida extracts as therapies for neurologic disorders.

  16. Combination of Cymbopogon citratus and Allium cepa essential oils increased antibacterial activity in leafy vegetables.

    Science.gov (United States)

    Ortega-Ramirez, Luis A; Silva-Espinoza, Brenda A; Vargas-Arispuro, Irasema; Gonzalez-Aguilar, Gustavo A; Cruz-Valenzuela, M Reynaldo; Nazzaro, Filomena; Ayala-Zavala, J Fernando

    2017-05-01

    Cymbopogon citratus and Allium cepa essential oils (EOs) are rich in terpenes and sulfur compounds respectively, both with antibacterial activity and different cell targets, supporting the idea that their combination can increase their efficacy. Major constituents of C. citratus were geranial and neral, while A. cepa presented dipropyl disulfide and dipropyl trisulfide. Cymbopogon citratus and A. cepa EOs inhibited the in vitro growth of Escherichia coli O157:H7 (minimal inhibitory concentrations of 2.21 and 5.13 g L-1 respectively), Salmonella Choleraesuis (3.04 and 1.28 g L-1 ), Listeria monocytogenes (1.33 and 2.56 g L-1 ) and Staphylococcus aureus (0.44 and 5.26 g L-1 ). Application of the EO combination to spinach caused a greater reduction in E. coli (2.34 log colony-forming units (CFU) g-1 ), S. Choleraesuis (2.94 log CFU g-1 ), L. monocytogenes (2.06 log CFU g-1 ) and S. aureus (1.37 log CFU g-1 ) compared with higher doses of individual EOs; a similar effect was observed for romaine lettuce. Individual and combined EOs caused a reduction in flavor acceptability level; however, no significant differences were found among odor acceptability of control vegetables and those treated with the EO combination and C. citratus EO. Leafy vegetables treated with the EO combination showed higher antibacterial protection and odor acceptability compared with individual EO treatments. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  17. Anti-inflammatory activity of Cymbopogon citratus leaves infusion via proteasome and nuclear factor-κB pathway inhibition: contribution of chlorogenic acid.

    Science.gov (United States)

    Francisco, Vera; Costa, Gustavo; Figueirinha, Artur; Marques, Carla; Pereira, Paulo; Miguel Neves, Bruno; Celeste Lopes, Maria; García-Rodríguez, Carmen; Teresa Cruz, Maria; Teresa Batista, Maria

    2013-06-21

    Cymbopogon citratus (DC.) Stapf leaves infusion is used in traditional medicine for the treatment of inflammatory conditions, however little is known about their bioactive compounds. Investigate the compounds responsible for anti-inflammatory potential of Cymbopogon citratus (Cy) on cytokines production induced by lipopolysaccharide (LPS) in human and mouse macrophages, and the action mechanisms involved. An essential oil-free infusion of Cy was prepared and polyphenol-rich fractions (PFs) were obtained from it by column chromatography. Chlorogenic acid (CGA) was identified, by HPLC/PDA/ESI-MS(n). The expression of cytokines, namely TNF-α and CCL5, was analyzed by real-time RT-PCR, on LPS-stimulated human macrophages. Activation of nuclear factor (NF)-κB, a master regulator of inflammation, was investigated by western blot and gene reporter assay. Proteasome activity was assessed using a fluorogenic peptide. Cymbopogon citratus extract and its polyphenols inhibited the cytokine production on human macrophages. This supports the anti-inflammatory activity of Cy polyphenols in physiologically relevant cells. Concerning the effect on the activation of NF-κB pathway, the results pointed to an inhibition of LPS-induced NF-κB activation by Cy and PFs. CGA was identified, by HPLC/PDA/ESI-MS(n), as the main phenolic acid of the Cy infusion, and it demonstrated to be, at least in part, responsible by that effect. Additionally, it was verified for the first time that Cy and PFs inhibited the proteasome activity, a complex that controls NF-κB activation, having CGA a strong contribution. The results evidenced, for the first time, the anti-inflammatory properties of Cymbopogon citratus through proteasome inhibition and, consequently NF-κB pathway and cytokine expression. Additionally, Cy polyphenols, in particular chlorogenic acid, were highlighted as bioactive compounds. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. ( Cymbopogon citratus Stapf) powder and essential oil on mould ...

    African Journals Online (AJOL)

    After 6 months in farmers' stores, unshelled melon seeds treated with 0.5% (v/w) of essential oil and 10% (w/w) of powdered leaves of C. citratus had significantly lower proportion of visibly diseased seeds and Aspergillus spp infestation levels and significantly higher seed germination compared to the untreated seeds.

  19. Phytoconstituents and diuretic activity of Cymbopogon citratus leaf infusions in humans

    Directory of Open Access Journals (Sweden)

    Christopher Ekpenyong

    2014-09-01

    Full Text Available Objective: To assess the diuretic activity of infusions prepared from Cymbopogon citratus (C. citratus leaves in healthy volunteers. Methods: One hundred and five subjects (55 men and 50 women aged 18 to 35 years were randomly assigned to groups set to orally receive infusions prepared from 2, 4, or 8 g of C. citratus leaf powder, once daily for 30 d. Urine volume, frequency of urination, urine specific gravity, and plasma and urinary levels of electrolytes were assessed 1 day before (baseline, and at 10 and 30 d after initiation of treatment. Computed diuretic indices were compared between experimental and baseline values. Results: Subjects treated with infusions prepared from C. citratus leaf powder which tested positive for saponins, tannins, flavaniods, phenols, anthraquinones, alkaloids, and deoxy-sugar exhibited a significant increase in indices of diuresis including urine volume, urination frequency, diuretic action, natriuretic and saliuretic indices and renal fractional excretion of electrolytes and metabolic acidosis. A non-significant change in urine specific gravity was observed in all groups. eGFR showed a non-significant increase at Day 10, but decreased significantly (P<0.05 at Day 30. Thiazide and aldosterone secretion indices decreased at Day 10, whereas carbonic anhydrase index increased significantly (P<0.05 at both Days 10 and 30. Conclusions: These results indicate a loop active diuretic action of C. citratus infusion.

  20. Hepatoprotective and antioxidant effects of Cymbopogon citratus Stapf

    African Journals Online (AJOL)

    Purpose: To investigate the protective effect of Cymbopogon citrates Stapf. (CS, lemongrass) extract on paracetamol (PCM)-induced hepatotoxicity in rats. Methods: The rats were orally administered CS extract (1000 mg/kg/day) for 30 days prior to induction of hepatotoxicity by a single oral administration of PCM (3 g/kg).

  1. Control of Colletotrichum gloeosporioides (penz. Sacc. In yellow passion fruit using Cymbopogon citratus essential oil

    Directory of Open Access Journals (Sweden)

    Nina Duarte Anaruma

    2010-03-01

    Full Text Available The use of antibiotics in agriculture is limited when compared to their applications in human and veterinary medicine. On the other hand, the use of antimicrobials in agriculture contributes to the drug resistance of human pathogens and has stimulated the search for new antibiotics from natural products. Essential oils have been shown to exert several biological activities including antibacterial and antifungal actions. The aim of this study was to determine the activity of 28 essential oils from medicinal plants cultivated at CPMA (Medicinal and Aromatic Plants Collection, CPQBA/UNICAMP, against Colletotrichum gloeosporioides (Penz. Sacc., the anthracnose agent in yellow passion fruit (Passiflora edulis Sims f. flavicarpa Deg, as well as evaluating their effect in the control of post-harvest decay. The oils were obtained by water-distillation using a Clevenger-type system and their minimal inhibitory concentrations (MIC determined by the micro-dilution method. According to the results, 15 of the 28 essential oils presented activity against Colletotrichum gloeosporioides, and the following four oils presented MIC values between 0.25 and 0.3 mg/mL: Coriandrum sativum, Cymbopogon citratus, Cymbopogon flexuosus and Lippia alba. The evaluation of Cymbopogon citratus essential oil in the control of post-harvest decay in yellow passion fruit showed that the disease index of the samples treated with the essential oil did not differ (P < 0.05 from that of the samples treated with fungicide. The present study shows the potential of Cymbopogon citratus essential oil in the control of the anthracnose agent in yellow passion fruit.

  2. Control of Colletotrichum gloeosporioides (penz.) Sacc. In yellow passion fruit using Cymbopogon citratus essential oil.

    Science.gov (United States)

    Anaruma, Nina Duarte; Schmidt, Flávio Luís; Duarte, Marta Cristina Teixeira; Figueira, Glyn Mara; Delarmelina, Camila; Benato, Liane Aparecida; Sartoratto, Adilson

    2010-01-01

    The use of antibiotics in agriculture is limited when compared to their applications in human and veterinary medicine. On the other hand, the use of antimicrobials in agriculture contributes to the drug resistance of human pathogens and has stimulated the search for new antibiotics from natural products. Essential oils have been shown to exert several biological activities including antibacterial and antifungal actions. The aim of this study was to determine the activity of 28 essential oils from medicinal plants cultivated at CPMA (Medicinal and Aromatic Plants Collection), CPQBA/UNICAMP, against Colletotrichum gloeosporioides (Penz.) Sacc., the anthracnose agent in yellow passion fruit (Passiflora edulis Sims f. flavicarpa Deg), as well as evaluating their effect in the control of post-harvest decay. The oils were obtained by water-distillation using a Clevenger-type system and their minimal inhibitory concentrations (MIC) determined by the micro-dilution method. According to the results, 15 of the 28 essential oils presented activity against Colletotrichum gloeosporioides, and the following four oils presented MIC values between 0.25 and 0.3 mg/mL: Coriandrum sativum, Cymbopogon citratus, Cymbopogon flexuosus and Lippia alba. The evaluation of Cymbopogon citratus essential oil in the control of post-harvest decay in yellow passion fruit showed that the disease index of the samples treated with the essential oil did not differ (P ≤ 0.05) from that of the samples treated with fungicide. The present study shows the potential of Cymbopogon citratus essential oil in the control of the anthracnose agent in yellow passion fruit.

  3. Chemical composition and antimicrobial activity of Cymbopogon citratus and Cymbopogon giganteus essential oils alone and in combination.

    Science.gov (United States)

    Bassolé, I H N; Lamien-Meda, A; Bayala, B; Obame, L C; Ilboudo, A J; Franz, C; Novak, J; Nebié, R C; Dicko, M H

    2011-09-15

    As part of ongoing research on the chemical composition and the antimicrobial properties of Burkinabe plants essential oils alone and in combination, essential oils (EOs) from leaves of Cymbopogon citratus and Cymbopogon giganteus from Burkina Faso were analyzed by GC-FID and GC-MS. Five constituents, which accounted for 96.3% of the oil, were identified in the EO of C. citratus. Geranial (48.1%), neral (34.6%) and myrcene (11.0%) were the major constituents. For C. giganteus a total of eight compounds were identified which represented 86.0% of the oils extracted. The dominant compounds were limonene (42%) and a set of monoterpene alcohols: trans-p-mentha-1(7),8-dien-2-ol (14.2%), cis-p-mentha-1(7),8-dien-2-ol (12%), trans-p-mentha-2,8-dien-1-ol (5.6%) and cis-p-mentha-2,8-dien-1-ol (5.2%). The EOs were tested against nine bacteria by using disc diffusion and microdilution methods. C. giganteus EO showed antimicrobial effects against all microorganisms tested whereas C. citratus EO failed to inhibit Pseudomonas aeruginosa. The antimicrobial activity of combinations of the two EOs was quantified by the checkerboard method. Combinations of the two EOs exerted synergistic, additive and indifferent antimicrobial effects. Results of the present investigation provide evidence that the combinations of plant EOs could be assessed for synergistic activity in order to reduce their minimum effective dose. Copyright © 2011 Elsevier GmbH. All rights reserved.

  4. Lemon grass (Cymbopogon citratus) essential oil as a potent anti-inflammatory and antifungal drugs.

    Science.gov (United States)

    Boukhatem, Mohamed Nadjib; Ferhat, Mohamed Amine; Kameli, Abdelkrim; Saidi, Fairouz; Kebir, Hadjer Tchoketch

    2014-01-01

    Volatile oils obtained from lemon grass [Cymbopogon citratus (DC.) Stapf, Poaceae family] are used in traditional medicine as remedies for the treatment of various diseases. In the present study, lemon grass essential oil (LGEO) was evaluated for its in vivo topical and oral anti-inflammatory effects, and for its in vitro antifungal activity using both liquid and vapor phases. The chemical profile of LGEO as determined by gas chromatography-mass spectrometry analysis revealed two major components: geranial (42.2%), and neral (31.5%). The antifungal activity of LGEO was evaluated against several pathogenic yeasts and filamentous fungi using disc diffusion and vapor diffusion methods. LGEO exhibited promising antifungal effect against Candida albicans, C. tropicalis, and Aspergillus niger, with different inhibition zone diameters (IZDs) (35-90 mm). IZD increased with increasing oil volume. Significantly, higher anti-Candida activity was observed in the vapor phase. For the evaluation of the anti-inflammatory effect, LGEO (10 mg/kg, administered orally) significantly reduced carrageenan-induced paw edema with a similar effect to that observed for oral diclofenac (50 mg/kg), which was used as the positive control. Oral administration of LGEO showed dose-dependent anti-inflammatory activity. In addition, topical application of LGEO in vivo resulted in a potent anti-inflammatory effect, as demonstrated by using the mouse model of croton oil-induced ear edema. To our knowledge, this is the first such report to be published. The topical application of LGEO at doses of 5 and 10 µL/ear significantly reduced acute ear edema induced by croton oil in 62.5 and 75% of the mice, respectively. In addition, histological analysis clearly confirmed that LGEO inhibits the skin inflammatory response in animal models. RESULTS of the present study indicate that LGEO has a noteworthy potential for the development of drugs for the treatment of fungal infections and skin inflammation that

  5. Protective effect of Cymbopogon citratus on hydrogen peroxide-induced oxidative stress in the reproductive system of male rats.

    Science.gov (United States)

    Rahim, Saleh M; Taha, Ekhlass M; Mubark, Zaid M; Aziz, Salam S; Simon, K D; Mazlan, A G

    2013-12-01

    Cymbopogon citratus (C. citratus) has antioxidant, anti-inflammatory, and chemoprotective properties. This study was conducted to evaluate the protective effect of C. citratus aqueous extract against hydrogen peroxide (H2O2)-induced oxidative stress and injury in the reproductive system of male rats. The twenty-five rats used in this study were divided into five groups, comprised of five rats each. The control group received standard food and drink. The H2O2 group received standard food and water with 0.5% H2O2. The rats in the H2O2 + C. citratus group and H2O2 + vitamin E group received standard food, H2O2, and C. citratus [100 mg·kg(-1) body weight (bw)], or vitamin E as an antioxidant reference (500 mg·kg(-1) bw), respectively. The C. citratus group was given C. citratus (100 mg·kg(-1) bw) in addition to the standard food and drink. The treatments were administered for 30 days. The H2O2 treatment significantly (P citratus, vitamin E, and H2O2 treatment significantly (P citratus aqueous extract reduced oxidative stress and protected male rats against H2O2-induced reproductive system injury.

  6. Spasmolytic effect of citral and extracts of Cymbopogon citratus on isolated rabbit ileum.

    Science.gov (United States)

    Devi, Ramachandran Chitra; Sim, Si Mui; Ismail, Rosnah

    2011-01-01

    Cymbopogon citratus, commonly known as lemongrass, has been shown to have antioxidant, antimicrobial and chemo-protective properties. Citral, a monoterpenoid, is the major constituent of C. citratus that gives off a lemony scent and is postulated to be responsible for most of its actions. In addition, C. citratus has been traditionally used to treat gastrointestinal discomforts, however, the scientific evidence for this is still lacking. Thus, the aim of the present study was to investigate the effect of the extracts of various parts of C. citratus (leaves, stems and roots) and citral on the visceral smooth muscle activity of rabbit ileum. The effect of the test substances were tested on the spontaneous contraction, acetylcholine (ACh)- and KCl-induced contractions. Citral at doses between 0.061 mM to 15.6 mM and the extract of leaves at doses between 0.001 mg/mL to 1 mg/mL significantly reduced the spontaneous, ACh- and KCl-induced ileal contractions. When the ileum was incubated in K(+)-rich-Ca(2+)-free Tyrode's solution, it showed only minute contractions. However, the strength of contraction was increased with the addition of increasing concentrations of CaCl(2). The presence of citral almost abolished the effect of adding CaCl(2), while the leaf extract shifted the calcium concentration-response curve to the right, suggesting a calcium antagonistic effect. These results were similar to that elicited by verapamil, a known calcium channel blocker. In addition, the spasmolytic effect of citral was observed to be reduced by the nitric oxide synthase inhibitor, L-NAME. In conclusion, citral and the leaf extract of C. citratus exhibited spasmolytic activity and it appeared that they may act as calcium antagonists. Furthermore, the relaxant effect of citral, but not that of the leaf extract may be mediated by nitric oxide suggesting the presence of other chemical components in the leaf extract other than citral.

  7. Effect of Cymbopogon citratus and Citral on Vascular Smooth Muscle of the Isolated Thoracic Rat Aorta.

    Science.gov (United States)

    Devi, R Chitra; Sim, S M; Ismail, R

    2012-01-01

    Cymbopogon citratus has been shown to have antioxidant, antimicrobial, antispasmodic and chemo-protective properties. Citral, is the major constituent of C. citratus. This study investigated the effects of methanolic extracts of leaves (LE), stems (SE), and roots (RE) of C. citratus and citral on vascular smooth muscle and explored their possible mechanisms of action. The experiment was conducted using isolated tissue preparations, where citral, LE, SE, and RE were added separately into a tissue bath that contained aortic rings, which were pre-contracted with phenylephrine (PE). Citral, LE, and RE exhibited a dose-dependent relaxant effect on the PE-induced contractions. Citral appeared to partially act via NO as its vasorelaxant effect was attenuated by L-NAME. However, the effect of LE may involve prostacyclin as indomethacin reversed the relaxant effect of LE on the PE-induced contraction. Furthermore, citral, LE, and RE abolished the restoration of PE-induced contraction caused by the addition of increasing doses of calcium in both endothelium intact and denuded rings. These findings suggest that the relaxation effect of citral, LE, and RE is endothelium-independent and may be mainly by affecting the intracellular concentration of calcium. Citral may partially act through the NO pathway while a vasodilator prostaglandin may mediate the effect of LE.

  8. Essential Oil of Cymbopogon citratus on the Control of the Curvularia Leaf Spot Disease on Maize.

    Science.gov (United States)

    Mourão, Dalmarcia de Sousa Carlos; Ferreira de Souza Pereira, Talita; Souza, Danival José de; Chagas Júnior, Aloísio Freitas; Dalcin, Mateus Sunti; Veloso, Ronice Alves; Leão, Evelynne Urzêdo; Santos, Gil Rodrigues Dos

    2017-08-20

    The Curvularia Leaf Spot is becoming more common due to the culture expansion and the low resistance of the cultivated genotypes in tropical regions. Thus, the objective was to evaluate the fungitoxicity of the essential oil of Cymbopogon citratus upon the phytopathogen Curvularia lunata, causative agent of the Curvularia Leaf Spot. There was realized pathogenicity tests of C. lunata in maize plants, phytotoxicity of the essential oil of C. citratus and gas chromatography attached, germination tests of the conidia, and of in vitro inhibition of C. lunata. Also, there were realized tests aiming at verifying the phytopathogen control in vivo. In the pathogenicity tests, there were verified symptoms of the disease in all of the suspensions tested on plants. It was observed that the essential oil concentrations of 7.5 µL mL-1 to 50 µL mL-1 were phytotoxic. The majoritarian chemical components of the essential oil of C. citratus were Geranial (41.46%) and Neral (32.43%). The concentrations of 5 and 7.5 µL mL-1 inhibited 100% of conidia germination. None of the concentrations evaluated effectively inhibited C. lunata mycelial growth in in vitro tests. In the preventive control, the concentration of 7.5 µL mL-1 was sufficient for the reduction of the progress of the disease, however the curative control was not efficient on the tested dosages.

  9. Investigation of the mechanisms underlying the gastroprotective effect of cymbopogon citratus essential oil.

    Science.gov (United States)

    Fernandes, Cn; De Souza, Hf; De Oliveria, G; Costa, Jgm; Kerntopf, Mr; Campos, Ar

    2012-01-01

    Cymbopogon citratus is a medicinal plant popularly used in Brazil for the treatment of various diseases, and the research interest in this plant is justifiable because of its potential medicinal value in stomachache and gastric ulcer. This study was aimed to test the validity of this practice by using experimental models of gastric ulcer and to clarify the mechanisms of gastroprotection by C. citratus leaves essential oil (EOCC). EOCC was evaluated for the ability to protect the gastric mucosa against injuries caused by necrotizing agents (absolute ethanol and aspirin) in rodents. The results of this study revealed that EOCC posses a dose-independent anti-ulcer effect against the different experimental models. EOCC pretreatment depicted a higher preventive index in ethanol-(88%) and aspirin-induced (76%) acute ulceration. On pretreatment of mice with indomethacin, the cyclooxygenase inhibitor slightly suppressed the gastroprotective effect of EOCC (48.5%). Furthermore, EOCC gastroprotection was not attenuated in mice pretreated with L-NAME (85.2%), glibenclamide (100%), or yohimbine (79.7%), the respective inhibitors of nitric oxide synthase, K(+) (ATP) channel activation, and α(2) receptors. These results confirmed the traditional use of C. citratus for the treatment of gastric ulcer. Thus, we provide the first evidence that EOCC reduces gastric damage induced by ethanol, at least in part, by mechanisms that involve endogenous prostaglandins.

  10. Activity of Ocimum basilicum, Ocimum canum, and Cymbopogon citratus essential oils against Plasmodium falciparum and mature-stage larvae of Anopheles funestus s.s

    National Research Council Canada - National Science Library

    Akono Ntonga, Patrick; Baldovini, Nicolas; Mouray, Elisabeth; Mambu, Lengo; Belong, Philippe; Grellier, Philippe

    2014-01-01

    The biological activities of essential oils from three plants grown in Cameroon: Ocimum basilicum, Ocimum canum, and Cymbopogon citratus were tested against Plasmodium falciparum and mature-stage larvae of Anopheles funestus...

  11. Lemon grass (Cymbopogon citratus essential oil as a potent anti-inflammatory and antifungal drugs

    Directory of Open Access Journals (Sweden)

    Mohamed Nadjib Boukhatem

    2014-09-01

    Full Text Available Background: Volatile oils obtained from lemon grass [Cymbopogon citratus (DC. Stapf, Poaceae family] are used in traditional medicine as remedies for the treatment of various diseases. Aims: In the present study, lemon grass essential oil (LGEO was evaluated for its in vivo topical and oral anti-inflammatory effects, and for its in vitro antifungal activity using both liquid and vapor phases. Methods: The chemical profile of LGEO as determined by gas chromatography–mass spectrometry analysis revealed two major components: geranial (42.2%, and neral (31.5%. The antifungal activity of LGEO was evaluated against several pathogenic yeasts and filamentous fungi using disc diffusion and vapor diffusion methods. Results: LGEO exhibited promising antifungal effect against Candida albicans, C. tropicalis, and Aspergillus niger, with different inhibition zone diameters (IZDs (35–90 mm. IZD increased with increasing oil volume. Significantly, higher anti-Candida activity was observed in the vapor phase. For the evaluation of the anti-inflammatory effect, LGEO (10 mg/kg, administered orally significantly reduced carrageenan-induced paw edema with a similar effect to that observed for oral diclofenac (50 mg/kg, which was used as the positive control. Oral administration of LGEO showed dose-dependent anti-inflammatory activity. In addition, topical application of LGEO in vivo resulted in a potent anti-inflammatory effect, as demonstrated by using the mouse model of croton oil-induced ear edema. To our knowledge, this is the first such report to be published. The topical application of LGEO at doses of 5 and 10 µL/ear significantly reduced acute ear edema induced by croton oil in 62.5 and 75% of the mice, respectively. In addition, histological analysis clearly confirmed that LGEO inhibits the skin inflammatory response in animal models. Conclusion: Results of the present study indicate that LGEO has a noteworthy potential for the development of drugs for

  12. Antioxidant potential of Cymbopogon citratus extract: alleviation of carbon tetrachloride-induced hepatic oxidative stress and toxicity.

    Science.gov (United States)

    Koh, Pei Hoon; Mokhtar, Ruzaidi Azli Mohd; Iqbal, Mohammad

    2012-01-01

    This study was aimed to evaluate the effect of Cymbopogon citratus against carbon tetrachloride (CCl(4))-mediated hepatic oxidative damage in rats. Rats were administrated with C. citratus extract (100, 200 and 300 mg/kg b.w.) for 14 days before the challenge of CCl(4) (1.2 ml/kg b.w. p.o) on 13th and 14th days. Hepatic damage was evaluated by employing serum biochemical parameters (alanine aminotransferase-ALT, aspartate aminotransferase-AST and lactate dehydrogenase-LDH), malondialdehye (MDA) level, reduced GSH and antioxidant enzymes (catalase: CAT, glutathione peroxidase: GPX, quinone reductase: QR, glutathione S-transferase: GST, glutathione reductase: GR, glucose-6-phosphate dehyrogenase: G6PD). In addition, CCl(4)-mediated hepatic damage was further evaluated by histopathological examination. However, most of these changes were alleviated by prophylactic treatment of animals with C. citratus dose dependently (p citratus might be ascribable to its antioxidant and free radical scavenging property.

  13. Effectiveness of Cymbopogon citratus L. essential oil to inhibit the growth of some filamentous fungi and yeasts.

    Science.gov (United States)

    Irkin, Reyhan; Korukluoglu, Mihriban

    2009-02-01

    Lemon grass (Cymbopogon citratus L.) oil has been known as having therapeutic and antibacterial properties, and its antifungal activity is currently the subject of renewed interest. This study aimed to verify the effectivenesses of C. citratus essential oil to inhibit the growth/survival of some fungi (Alternaria alternata, Aspergillus niger, Fusarium oxysporum, and Penicillium roquefortii) and yeasts (Candida albicans, Candida oleophila, Hansenula anomala, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Saccharomyces uvarum, and Metschnikowia fructicola). C. citratus essential oil showed effectiveness in inhibiting the growth of all fungi by disc diffusion and broth dilution bioassay. Minimum inhibitory and minimum fungicidal concentrations between 0.062 and 20 microL/mL were determined. The Clinical and Laboratory Standards Institute agar-based method was also applied for A. niger and C. albicans. Data show the strong antifungal properties of lemon grass oil (C. citratus) in vitro.

  14. Evaluation of the lemongrass plant (Cymbopogon citratus extracted in different solvents for antioxidant and antibacterial activity against human pathogens

    Directory of Open Access Journals (Sweden)

    Balachandar Balakrishnan

    2014-02-01

    Full Text Available Objective: To test antibacterial and antioxidant activity of the lemongrass plant Cymbopogon citratus (C. citratus leaves extracted serially by the solvents (chloroform, methanol and water. Methods: The plant leaves extracts were used for antibacterial activity on Bacillus subtilis, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Nocardia sp., Serratia sp., and Enterobacter aeruginosa microorganisms by the Kirby Bauer agar disc diffusion method. This study was carried out on lemongrass plant leaf extracts in different concentration of all solvents. The leaf extracts from different solvents were tested for their scavenging activity against the stable free radical DPPH in quantization using a spectrophotometric assay. Oxidative damage was induced in vitro by treating blood DNA and analyzing the effects of the leaf extracts. Results: The results showed that C. citratus extracts exhibited maximum zones of inhibition in chloroform, methanol and water extracts. It was Observed that the C. citratus extracts exhibited maximum zone of inhibition against Bacillus subtilis, Pseudomonas aeruginosa and Proteus vulgaris. Analyzed data in the present work suggested that antibacterial activity of C. citratus plant leaf extracts showed good results for Gram-positive and Gram-negative organisms. DPPH scavenging activity was highly elicited by the extract of C. citratus. Chloroform, methanol and water extracts of C. citratus leaves effectively decreased the extent of DNA damage. Conclusions: The present study suggested that the lemongrass plant extracts could offer various health benefits.

  15. Use of Cymbopogon citratus essential oil in food preservation: Recent advances and future perspectives.

    Science.gov (United States)

    Ekpenyong, Christopher E; Akpan, Ernest E

    2017-08-13

    The economic burdens and health implications of food spoilage are increasing. Contamination of food sources by fungi, bacteria, yeast, nematodes, insects, and rodents remains a major public health concern. Research has focused on developing safer natural products and innovations to meet consumers' acceptance as alternatives to synthetic food preservatives. Many recent novel preservative techniques and applications of both natural and synthetic origin continue to proliferate in food and chemical industries. In particular, some essential oils of plant origin are potent food preservatives and are thus attractive alternatives to synthetic preservatives. This paper provides an overview of recent advances and future prospects in assessing the efficacy of the use of Cymbopogon citratus (lemongrass) essential oil in food preservation. The possible mechanisms of action and toxicological profile as well as evidence for or against the use of this essential oil as an alternative to synthetic food preservatives in domestic and industrial applications are discussed.

  16. Pharmacological evaluation of anxiolytic property of aqueous root extract of Cymbopogon citratus in mice

    Directory of Open Access Journals (Sweden)

    David Arome

    2014-01-01

    Full Text Available Aim: This study was designed to evaluate the anxiolytic property of aqueous root extract of Cymbopogon citratus in mice. Materials and Methods: In this study, stress induced hyperthermia (SIH, elevated plus maze (EPM and open field experimental models were employed. Results: In SIH model, the extract caused a significant (P 0.05 effect. In open field model, 200 mg/kg and 600 mg/kg extract doses significantly (P < 0.05 increased locomotion of the mice more than the standard, while rearing and defecation were less in the extract groups. Conclusion: In different experimental models used significant anxiolytic effect was observed of the aqueous extract at different dose levels in comparison to reference standard and normal saline group. This clearly justified its folkloric application in the treatment of anxiety disorders.

  17. Influence of agar concentration on in vitro multiplication of Cymbopogon citratus (D. C. Stapf

    Directory of Open Access Journals (Sweden)

    Ricardo J. Licea Moreno

    2001-04-01

    Full Text Available Here are presented the results on in vitro multiplication of lemon grass (Cymbopogon citratus (D. C. Stapf.; it is a very important medicinal plant because its analgesic, antinflamatory and hipotensor properties, among others, useful to elaborate several medicaments with a high popular acceptation. The main aim of this research was to set up the influence of agar concentration in culture medium during in vitro establishment on multiplication of lemon grass. Were used three treatments: (1 liquid medium with filter paper bridges, (2 3 g.l-1 of agar (BIOCEN and (3 6 g.l-1 of agar (BIOCEN. The explants were inoculated on a culture media containing Murashige and Skoog salts (1962, Heinz and Mee vitamins (1969, myoinositol 100 mg.l-1, 6-BAP 0.2 mg.l-1 and sucrose 20 g.l-1. Meristematic tips were inoculated on the treatments described above under sun light conditions, once desinfected. The explants Influence of agar concentration on in vitro multiplication of Cymbopogon citratus (D. C. Stapf. were maintained 21 days in this culture media and later it is were subcultured 5 times each 21 days, on the same multiplication culture media containing Murashige and Skoog salts (1962, tiamine 1 mg.l-1, myoinositol 100 mg.l-1, 6-BAP 0.3 mg.l-1 and sucrose 30 g.l-1. The pH was 5.7 for all culture media. The results showed the relevance of agar concentration during in vitro establishment on multiplication of lemon grass. Differences among treatments until the 2nd subculture was observed. 3.43 new axillary shoots from each explant cultured on a culture media supplemented with 3 g.l-1 of agar was reached. Key words: lemon grass, medicinal plants, micropropagation, tissue culture

  18. The GABAergic system contributes to the anxiolytic-like effect of essential oil from Cymbopogon citratus (lemongrass).

    Science.gov (United States)

    Costa, Celso A Rodrigues de Almeida; Kohn, Daniele Oliveira; de Lima, Valéria Martins; Gargano, André Costa; Flório, Jorge Camilo; Costa, Mirtes

    2011-09-01

    The essential oil (EO) from Cymbopogon citratus (DC) Stapf is reported to have a wide range of biological activities and is widely used in traditional medicine as an infusion or decoction. However, despite this widely use, there are few controlled studies confirming its biological activity in central nervous system. The anxiolytic-like activity of the EO was investigated in light/dark box (LDB) and marble-burying test (MBT) and the antidepressant activity was investigated in forced-swimming test (FST) in mice. Flumazenil, a competitive antagonist of benzodiazepine binding and the selective 5-HT(1A) receptor antagonist WAY100635 was used in experimental procedures to determine the action mechanism of EO. To exclude any false positive results in experimental procedures, mice were submitted to the rota-rod test. We also quantified some neurotransmitters at specific brain regions after EO oral acute treatment. The present work found anxiolytic-like activity of the EO at the dose of 10mg/kg in a LDB. Flumazenil, but not WAY100635, was able to reverse the effect of the EO in the LDB, indicating that the EO activity occurs via the GABA(A) receptor-benzodiazepine complex. Only at higher doses did the EO potentiate diethyl-ether-induced sleeping time in mice. In the FST and MBT, EO showed no effect. Finally, the increase in time spent in the light chamber, demonstrated by concomitant treatment with ineffective doses of diazepam (DZP) and the EO, revealed a synergistic effect of the two compounds. The lack of activity after long-term treatment in the LDB test might be related to tolerance induction, even in the DZP-treated group. Furthermore, there were no significant differences between groups after either acute or repeated treatments with the EO in the rota-rod test. Neurochemical evaluation showed no amendments in neurotransmitter levels evaluated in cortex, striatum, pons, and hypothalamus. The results corroborate the use of Cymbopogon citratus in folk medicine and

  19. Chemical composition and insecticidal activity of Cymbopogon citratus essential oil from Cuba and Brazil against housefly

    Directory of Open Access Journals (Sweden)

    Zeneida Teixeira Pinto

    Full Text Available Essential oil of Cymbopogon citratus collected from Brazil and Cuba was tested to a chemical characterization and then was tested on the post-embryonic development of Musca domestica. The chemical composition analysis by GC-MS of the oils from Brazil/Cuba allowed the identification of 13 and 12 major constituents respectively; nine of them common to both. In the both oils, the main components were the isomers geranial and neral, which together form the compound citral. This corresponds to a total of 97.92%/Brazil and 97.69%/Cuba of the compounds identified. The monoterpene myrcene, observed only in the sample of Cuba, presented a large relative abundance (6.52%. The essential oil of C. citratus (Brazil/Cuba was dissolved in DMSO and tested at concentrations of 5, 10, 25, 50, 75 and 100% and citral was prepared by mixing 16.8 mg with 960 µL DMSO. Both essential oils and monoterpene citral were applied topically to newly-hatched larvae (1µL/larva. The results showed a lethal concentration (LC50 of 4.25 and 3.24% for the Brazilian and Cuban essential oils, respectively. Mortalities of larval and newly-hatched larvae to adult periods were dose-dependent for the two both oils as for monoterpene citral, reaching 90%. Both essential oils and citral caused morphological changes in adult specimens.

  20. Activation of intrinsic apoptotic signaling pathway in cancer cells by Cymbopogon citratus polysaccharide fractions.

    Science.gov (United States)

    Thangam, Ramar; Sathuvan, Malairaj; Poongodi, Arasu; Suresh, Veeraperumal; Pazhanichamy, Kalailingam; Sivasubramanian, Srinivasan; Kanipandian, Nagarajan; Ganesan, Nalini; Rengasamy, Ramasamy; Thirumurugan, Ramasamy; Kannan, Soundarapandian

    2014-07-17

    Essential oils of Cymbopogon citratus were already reported to have wide ranging medical and industrial applications. However, information on polysaccharides from the plant and their anticancer activities are limited. In the present study, polysaccharides from C. citratus were extracted and fractionated by anion exchange and gel filtration chromatography. Two different polysaccharide fractions such as F1 and F2 were obtained, and these fractions were found to have distinct acidic polysaccharides as characterized by their molecular weight and sugar content. NMR spectral analysis revealed the presence of (1→4) linked b-d-Xylofuranose moiety in these polysaccharides. Using these polysaccharide fractions F1 and F2, anti-inflammatory and anticancer activities were evaluated against cancer cells in vitro and the mechanism of action of the polysaccharides in inducing apoptosis in cancer cells via intrinsic pathway was also proposed. Two different reproductive cancer cells such as Siha and LNCap were employed for in vitro studies on cytotoxicity, induction of apoptosis and apoptotic DNA fragmentation, changes in mitochondrial membrane potential, and profiles of gene and protein expression in response to treatment of cells by the polysaccharide fractions. These polysaccharide fractions exhibited potential cytotoxic and apoptotic effects on carcinoma cells, and they induced apoptosis in these cells through the events of up-regulation of caspase 3, down-regulation of bcl-2 family genes followed by cytochrome c release. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Cymbopogon citratus essential oil: effect on polymicrobial caries-related biofilm with low cytotoxicity.

    Science.gov (United States)

    Oliveira, Maria Alcionéia Carvalho de; Borges, Aline Chiodi; Brighenti, Fernanda Lourenção; Salvador, Marcos José; Gontijo, Aline Vidal Lacerda; Koga-Ito, Cristiane Yumi

    2017-11-06

    The objective of this study was to evaluate the effects of Cymbopogon citratus essential oil and its main compound (citral) against primary dental colonizers and caries-related species. Chemical characterization of the essential oil was performed by gas chromatography/mass spectroscopy (GC/MS), and the main compound was determined. Antimicrobial activity was tested against Actinomyces naeslundii, Lactobacillus acidophilus, S. gordonii, S. mitis, S. mutans, S. sanguinis and S. sobrinus. Minimum inhibitory and bactericide concentrations were determined by broth microdilution assay for streptococci and lactobacilli reference, and for clinical strains. The effect of the essential oil on bacterial adhesion and biofilm formation/disruption was investigated. Negative (without treatment) and positive controls (chlorhexidine) were used. The effect of citral on preformed biofilm was also tested using the same methodology. Monospecies and microcosm biofilms were tested. ANOVA or Kruskal-Wallis tests were used (α=0.05). Cytotoxicity of the essential oil to human keratinocytes was performed by MTT assay. GC/MS demonstrated one major component (citral). The essential oil showed an inhibitory effect on all tested bacterial species, including S. mutans and L. acidophilus. Essential oil of C. citratus (10X MIC) reduced the number of viable cells of lactobacilli and streptococci biofilms (p biofilm to dental enamel (p biofilm (p dental biofilms.

  2. Chemical composition and insecticidal activity of Cymbopogon citratus essential oil from Cuba and Brazil against housefly.

    Science.gov (United States)

    Pinto, Zeneida Teixeira; Sánchez, Félix Fernández; dos Santos, Arith Ramos; Amaral, Ana Claudia Fernandes; Ferreira, José Luiz Pinto; Escalona-Arranz, Julio César; Queiroz, Margareth Maria de Carvalho

    2015-01-01

    Essential oil of Cymbopogon citratus collected from Brazil and Cuba was tested to a chemical characterization and then was tested on the post-embryonic development of Musca domestica. The chemical composition analysis by GC-MS of the oils from Brazil/Cuba allowed the identification of 13 and 12 major constituents respectively; nine of them common to both. In the both oils, the main components were the isomers geranial and neral, which together form the compound citral. This corresponds to a total of 97.92%/Brazil and 97.69%/Cuba of the compounds identified. The monoterpene myrcene, observed only in the sample of Cuba, presented a large relative abundance (6.52%). The essential oil of C. citratus (Brazil/Cuba) was dissolved in DMSO and tested at concentrations of 5, 10, 25, 50, 75 and 100% and citral was prepared by mixing 16.8 mg with 960 µL DMSO. Both essential oils and monoterpene citral were applied topically to newly-hatched larvae (1µL/larva). The results showed a lethal concentration (LC50) of 4.25 and 3.24% for the Brazilian and Cuban essential oils, respectively. Mortalities of larval and newly-hatched larvae to adult periods were dose-dependent for the two both oils as for monoterpene citral, reaching 90%. Both essential oils and citral caused morphological changes in adult specimens.

  3. STUDI PERBANDINGAN PERLAKUAN BAHAN BAKU DAN METODE DISTILASI TERHADAP RENDEMEN DAN KUALITAS MINYAK ATSIRI SEREH DAPUR (Cymbopogon citratus)

    OpenAIRE

    -, Slamet; -, Supranto; -, Riyanto

    2013-01-01

    Indonesia is rich in plant biodiversity. Indonesia volatile oil development efforts through increased development of one plant of lemon grass, which is one of the essential oil producing plants known as Cymbopogon citratus. Lemongrass essential oil in the chemical industry used as raw materials in the manufacture of cosmetics, perfume, deodorant, deodorant soap, floor cleaners and detergents.The purpose of this study was to determine the highest yield of lemongrass essential oil distillation ...

  4. In vitro antimicrobial properties of plant essential oils thymus vulgaris, cymbopogon citratus and laurus nobilis against five important foodborne pathogens

    OpenAIRE

    Alessandra Farias Millezi; Danila Soares Caixeta; Diogo Francisco Rossoni; Maria das Graças Cardoso; Roberta Hilsdorf Piccoli

    2012-01-01

    Several essential oils of condiment and medicinal plants possess proven antimicrobial activity and are of important interest for the food industry. Therefore, the Minimum Inhibitory Concentrations (MIC) of those oils should be determined for various bacteria. MIC varies according to the oil used, the major compounds, and the physiology of the bacterium under study. In the present study, the essential oils of the plants Thymus vulgaris (time), Cymbopogon citratus (lemongrass) and Laurus nobili...

  5. Evidence for the Involvement of Monoaminergic Pathways in the Antidepressant-Like Activity of Cymbopogon citratus in Mice.

    Science.gov (United States)

    Umukoro, Solomon; Ogboh, Somtochukwu I; Omorogbe, Osarume; Adekeye, Abdul-Lateef A; Olatunde, Matthew O

    2017-07-01

    Objectives Depression is a complex neuropsychiatric disorder, which affects the quality of life of the sufferers and treatment approach is associated with serious adverse effects and sometimes therapeutic failures. Cymbopogon citratus leaf (CC) has been reported to exert anti-depressant effect but its mechanism of action is yet to be elucidated hence, the need for this study. Methods The anti-depressant-like effect of Cymbopogon citratus aqueous leaf was evaluated using forced swim test (FST), tail suspension test (TST) and yohimbine-induced lethality test (YLT) in aggregated mice. Interaction studies involving p-chlorophenylalanine (pCPA), an inhibitor of serotonin biosynthesis and yohimbine, α2-adrenergic receptor antagonist were carried out to evaluate the role of monoaminergic system in the anti-depressant-like effect of CC. The effect of CC on spontaneous motor activity (SMA) was also assessed using activity cage. ResultsCymbopogon citratus (25 and 50 mg/kg, p.o.) demonstrated antidepressant-like activity devoid of significant stimulation of the SMA in mice. However, the antidepressant-like property of CC was significantly (pcitratus might be interacting with serotonergic and noradrenergic pathways to mediate its anti-depressant-like effect in mice. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Hepatoprotective effect of Cymbopogon citratus aqueous extract against hydrogen peroxide-induced liver injury in male rats.

    Science.gov (United States)

    Rahim, Saleh Muhammad; Taha, Ekhlass Muhi; Al-janabi, Muneef Saeb; Al-douri, Bushra Ismael; Simon, Kumar Das; Mazlan, Abd Gaffar

    2014-01-01

    Cymbopogon citratus (Poaceae) a tropical perennial herb plant that is widely cultivated to be eaten either fresh with food or dried in tea or soft drink has been reported to possess a number of medicinal and aromatic properties. This study aimed at evaluating the protective effects of C. citratus aqueous extract against liver injury induced by hydrogen peroxide (H2O2), in male rats. Twenty-five rats were randomly divided into five different groups of five animals in each group; (1) Control. (2) Received H2O2 (0.5%) with drinking water. (3), and (4) received H2O2 and C. citratus (100 mg·kg(-1) b wt), vitamin C (250 mg·kg(-1) b wt) respectively. (5), was given C. citratus alone. The treatments were administered for 30 days. Blood samples were collected and serum was used for biochemical assay including liver enzymes activities, total protein, total bilirubin and malonaldehyde, glutathione in serum and liver homogenates. Liver was excised and routinely processed for histological examinations. C. citratus attenuated liver damage due to H2O2 administration as indicated by the significant reduction (pcitratus could effectively ameliorate H2O2-induced oxidative stress and prevent liver injury in male rats.

  7. Anti-inflammatory activity of Cymbopogon citratus leaf infusion in lipopolysaccharide-stimulated dendritic cells: contribution of the polyphenols.

    Science.gov (United States)

    Figueirinha, Artur; Cruz, Maria Teresa; Francisco, Vera; Lopes, M Celeste; Batista, Maria Teresa

    2010-06-01

    Cymbopogon citratus, an herb known worldwide as lemongrass, is widely consumed as an aromatic drink, and its fresh and dried leaves are currently used in traditional cuisine. However, little is known about the mechanism of action of C. citratus, namely, the anti-inflammatory effects of its dietary components. Because nitric oxide (NO), produced in large quantities by activated inflammatory cells, has been demonstrated to be involved in the pathogenesis of acute and chronic inflammation, we evaluated the effects of the infusion of dried leaves from C. citratus, as well as its polyphenolic fractions--flavonoid-, tannin-, and phenolic acid-rich fractions (FF, TF, and PAF, respectively)--on the NO production induced by lipopolysaccharide (LPS) in a skin-derived dendritic cell line (FSDC). C. citratus infusion significantly inhibited the LPS-induced NO production and inducible NO synthase (iNOS) protein expression. All the polyphenolic fractions tested also reduced the iNOS protein levels and NO production stimulated by LPS in FSDC cells, without affecting cell viability, with the strongest effects being observed for the fractions with mono- and polymeric flavonoids (FF and TF, respectively). Our results also indicated that the anti-inflammatory properties of FF are mainly due to luteolin glycosides. In conclusion, C. citratus has NO scavenging activity and inhibits iNOS expression and should be explored for the treatment of inflammatory diseases, in particular of the gastrointestinal tract.

  8. Cymbopogon citratus essential oil: effect on polymicrobial caries-related biofilm with low cytotoxicity

    Directory of Open Access Journals (Sweden)

    Maria Alcionéia Carvalho de OLIVEIRA

    2017-11-01

    Full Text Available Abstract The objective of this study was to evaluate the effects of Cymbopogon citratus essential oil and its main compound (citral against primary dental colonizers and caries-related species. Chemical characterization of the essential oil was performed by gas chromatography/mass spectroscopy (GC/MS, and the main compound was determined. Antimicrobial activity was tested against Actinomyces naeslundii, Lactobacillus acidophilus, S. gordonii, S. mitis, S. mutans, S. sanguinis and S. sobrinus. Minimum inhibitory and bactericide concentrations were determined by broth microdilution assay for streptococci and lactobacilli reference, and for clinical strains. The effect of the essential oil on bacterial adhesion and biofilm formation/disruption was investigated. Negative (without treatment and positive controls (chlorhexidine were used. The effect of citral on preformed biofilm was also tested using the same methodology. Monospecies and microcosm biofilms were tested. ANOVA or Kruskal-Wallis tests were used (α=0.05. Cytotoxicity of the essential oil to human keratinocytes was performed by MTT assay. GC/MS demonstrated one major component (citral. The essential oil showed an inhibitory effect on all tested bacterial species, including S. mutans and L. acidophilus. Essential oil of C. citratus (10X MIC reduced the number of viable cells of lactobacilli and streptococci biofilms (p < 0.05. The essential oil inhibited adhesion of caries-related polymicrobial biofilm to dental enamel (p < 0.01. Citral significantly reduced the number of viable cells of streptococci biofilm (p < 0.001. The essential oil showed low cytotoxicity to human keratinocytes. Based on these findings, this study can contribute to the development of new formulations for products like mouthwash, against dental biofilms.

  9. Scaling-up the biomass production of Cymbopogon citratus L. in temporary immersion system

    Directory of Open Access Journals (Sweden)

    Elisa Quiala

    2014-04-01

    Full Text Available Shoot-tips, collected from greenhouse-grown plants of Cymbopogon citratus L. (lemmon grass, were incubated on a semi-solid Murashige and Skoog (MS medium with 30% (w/v sucrose, and supplemented with 0.89 µM 6-benzyladenine (BA. After three weeks of culture shoots were individualized and then inoculated in 10 litres temporary immersion system (TIS containing 3 litres of the same basal MS liquid medium. The effects of three immersion frequency (immersion every 12, 6 and 4 hours on the production of biomass were studied. Three inoculum densities (forty, fifty and sixty shoots/TIS were also tested. The biomass growth was inûuenced by the immersion frequency. The highest proliferation rate (17.3 shoots/explants and the plant length (45.2 cm were obtained in plants immersed every 4 h. Also, the fresh and dry biomass weight (153.4 gFW and 24.8 gDW, respectively were higher in this treatment. The maximum biomass accumulation (185.2 gFW and 35.2 gDW was achieved after 30 days of culture when an inoculum density of 60 explants per TIS was used. For the first time, biomass of C. citratus has been produced in10 litres TIS. These results represent the first step in the scaling-up the biomass production of this medicinal plant in large temporary immersion bioreactors. Key words: automation, biomass growth, lemmon grass medicinal plant, tissue culture

  10. Anti-proliferative effect and phytochemical analysis of Cymbopogon citratus extract.

    Science.gov (United States)

    Halabi, Mohammed F; Sheikh, Bassem Y

    2014-01-01

    The antiproliferative and antioxidant potential of Cymbopogon citratus (Lemon grass) extracts were investigated. The extracts were isolated by solvent maceration method and thereafter subjected to antiproliferative activity test on five different cancer cells: human colon carcinoma (HCT-116), breast carcinoma (MCF-7 and MDA-MB 231), ovarian carcinoma (SKOV-3 and COAV), and a normal liver cell line (WRL 68). The cell viability was determined using MTT assay. The DPPH radical scavenging assay revealed a concentration dependent trend. A maximum percentage inhibition of 45% and an IC50 of 278  μg/mL were observed when aqueous extract was evaluated. In contrast, 48.3% and IC50 of 258.9  μg/mL were observed when 50% ethanolic extract was evaluated. Both extracts at concentration of 50 to 800  μg/mL showed appreciative metal chelating activity with IC50 value of 172.2 ± 31  μg/mL to 456.5 ± 30  μg/mL. Depending on extraction solvent content, extract obtained from 50% ethanolic solvent proved to be more potent on breast cancer MCF-7 cell line (IC50 = 68  μg/mL). On the other hand, 90% ethanolic extract showed a moderate potency on the ovarian cancer (COAV) and MCF-7 cells having an IC50 of 104.6  μg/mL each. These results suggested antiproliferative efficacy of C. citratus ethanolic extract against human cancer cell lines.

  11. Acaricidal activity of Cymbopogon citratus and Azadirachta indica against house dust mites.

    Science.gov (United States)

    Hanifah, Azima Laili; Awang, Siti Hazar; Ming, Ho Tze; Abidin, Suhaili Zainal; Omar, Maizatul Hashima

    2011-10-01

    To examine the acaricidal effects of the essential oil of Cymbopogon citratus leaf extract (lemongrass) and ethanolic Azadirachta indica leaf extract (neem) against house dust mites Dermatophagoides farinae (D. farinae) and Dermatophagoides pteronyssinus (D. pteronyssinus). Twenty-five adults mites were placed onto treated filter paper that is soaked with plant extract and been tested at different concentrations (50.00%, 25.00%, 12.50%, 6.25% and 3.13%) and exposure times (24hrs, 48hrs, 72hrs and 96 hrs). All treatments were replicated 7 times, and the experiment repeated once. The topical and contact activities of the two herbs were investigated. Mortalities from lemongrass extract were higher than neem for both topical and contact activities. At 50 % concentration, both 24 hrs topical and contact exposures to lemongrass resulted in more than 91% mortalities for both species of mites. At the same concentration and exposure time, neem resulted in topical mortalities of 40.3% and 15.7% against D. pteronyssinus and D. farinae respectively; contact mortalities were 8.0% and 8.9% against the 2 mites, respectively. There was no difference in topical mortalities of D. pteronyssinus from exposure to concentrations of lemongrass and neem up to 12.50%; lemongrass was more effective than neem at the higher concentrations. Generally, topical mortalities of D. farinae due to lemongrass are higher than that due to neem. Contact mortalities of lemongrass are always higher that neem against both species of mites.

  12. Green synthesis, characterization and biological activities of silver nanoparticles from alkalinized Cymbopogon citratus Stapf

    Science.gov (United States)

    Ajayi, Emmanuel; Afolayan, Anthony

    2017-03-01

    Silver nanoparticles (AgNPs) have been synthesized from the alkalinized leaf extract of Cymbopogon citratus, also known as lemon grass (LG), and characterized for their size and shape using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The total formation of the AgNPs was observed visually with a color change from yellow to brownish-black. Fourier transform infrared spectroscopy (FTIR) and energy dispersive x-ray spectroscopy (EDS/EDX) were conducted to determine the various functional groups and the concentration of metal ions in the nanoparticles. The data analysis showed spherically shaped nanoparticles with a size of 10-33 nm, as revealed by TEM, thereby complementing the result for SEM. FTIR identifies the ethylene group as a reducing and capping agent for the formation of the nanoparticles. The x-ray diffraction pattern confirmed the presence of silver crystallites as well as their size, further confirming the result of the TEM. AgNPs do not exhibit very good potential as free radical scavengers when compared to the standards. The synthesized AgNPs in suspension showed activity against both gram-positive and gram-negative bacteria, with minimum inhibitory concentrations (MICs) in the range of 31.25-62.5 µg ml-1. In summary, the synthesized AgNPs possessed an acceptable size and shape.

  13. Optimized extraction of polysaccharides from Cymbopogon citratus and its biological activities.

    Science.gov (United States)

    Thangam, Ramar; Suresh, Veeraperumal; Kannan, Soundarapandian

    2014-04-01

    In this study the extraction of hot water soluble polysaccharides (HWSPs) from Cymbopogon citratus using hot water decoction was discussed. Response surface methodology (RSM) based on a three level, three variable central composite rotatable design (CCRD), was employed to obtain best possible combination of extraction time (X1: 30-180 min), extraction temperature (X2: 70-100 °C) and water to the raw material ratio (X3: 10-60) for maximum HWSPs extraction. The optimum extraction conditions were as follows: extraction time was around 113.81 min, extraction temperature at 99.66 °C and the ratio of water to raw material was 33.11 g/mL. Under these conditions, the experimental yield was 13.24±0.23%, which is well in close agreement with the value predicted by RSM model yield (13.19%). The basic characterization of HWSPs was determined by using the FTIR. These preliminary in vitro biological studies indicated that lemongrass polysaccharides were useful for anticancer therapy. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Cymbopogon citratus industrial waste as a potential source of bioactive compounds.

    Science.gov (United States)

    Tavares, Filipa; Costa, Gustavo; Francisco, Vera; Liberal, Joana; Figueirinha, Artur; Lopes, Maria Celeste; Cruz, Maria Teresa; Batista, Maria Teresa

    2015-10-01

    Cymbopogon citratus (Cc), commonly known as lemongrass, is a very important crop worldwide, being grown in tropical countries. It is widely used in the food, pharmaceutical, cosmetic and perfumery industries for its essential oil. Cc aqueous extracts are also used in traditional medicine. They contain high levels of polyphenols, which are known for their antioxidant and anti-inflammatory properties. Hydrodistillation of lemongrass essential oil produces an aqueous waste (CcHD) which is discarded. Therefore a comparative study between CcHD and Cc infusion (CcI) was performed to characterize its phytochemical profile and to research its antioxidant and anti-inflammatory potential. HPLC-PDA/ESI-MS(n) analysis showed that CcI and CcHD have similar phenolic profiles, with CcHD presenting a higher amount of polyphenols. Additionally, both CcI and CcHD showed antioxidant activity against DPPH (EC50 of 41.72 ± 0.05 and 42.29 ± 0.05 µg mL(-1) respectively) and strong anti-inflammatory properties, by reducing NO production and iNOS expression in macrophages and through their NO-scavenging activity, in a dose-dependent manner. Furthermore, no cytotoxicity was observed. The data of this study encourage considering the aqueous solution from Cc leaf hydrodistillation as a source of bioactive compounds, which may add great industrial value to this crop. © 2014 Society of Chemical Industry.

  15. Hypoglycemic and hypolipidemic effects of fresh leaf aqueous extract of Cymbopogon citratus Stapf. in rats.

    Science.gov (United States)

    Adeneye, Adejuwon Adewale; Agbaje, Esther Oluwatoyin

    2007-07-25

    The present study was designed to investigate the hypoglycemic and hypolipidemic effects of the single, daily oral dosing of 125-500 mg/kg of fresh leaf aqueous extract of Cymbopogon citratus Stapf. (CCi) in normal, male Wistar rats for 42 days. The average weights of rats per group were taken at 2 weeks interval for 42 days. On day 43, blood samples from the rats were collected for fasting plasma glucose (FPG), total cholesterol, triglycerides, low-density lipoproteins (LDL-c), very low-density lipoprotein (VLDL-c) and high-density lipoprotein (HDL-c) assays through cardiac puncture under halothane anesthesia. Acute oral dose toxicity study of CCi was also conducted using limit dose test of the Up and Down Procedure statistical program (AOT425StatPgm, Version 1.0) at a dose of 5000 mg/kg body weight/oral route. Our results showed CCi to lower FPG and lipid parameters dose dependently (p0.05). Results of acute oral toxicity showed CCi to be of low toxicity and as such could be considered relatively safe on acute exposure. Thus, confirming its folkloric use and safety in suspected Type 2 diabetic patients.

  16. Protective Effect of Cymbopogon citratus Essential Oil in Experimental Model of Acetaminophen-Induced Liver Injury.

    Science.gov (United States)

    Uchida, Nancy Sayuri; Silva-Filho, Saulo Euclides; Aguiar, Rafael Pazinatto; Wiirzler, Luiz Alexandre Marques; Cardia, Gabriel Fernando Esteves; Cavalcante, Heitor Augusto Otaviano; Silva-Comar, Francielli Maria de Souza; Becker, Tânia Cristina Alexandrino; Silva, Expedito Leite; Bersani-Amado, Ciomar Aparecida; Cuman, Roberto Kenji Nakamura

    2017-01-01

    To investigate the hepatoprotective effect of Cymbopogon citratus or lemongrass essential oil (LGO), it was used in an animal model of acute liver injury induced by acetaminophen (APAP). Swiss mice were pretreated with LGO (125, 250 and 500[Formula: see text]mg/kg) and SLM (standard drug, 200[Formula: see text]mg/kg) for a duration of seven days, followed by the induction of hepatotoxicity of APAP (single dose, 250[Formula: see text]mg/kg). The liver function markers alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and gamma-glutamyl transferase were determined to evaluate the hepatoprotective effects of the LGO. The livers were used to determine myeloperoxidase (MPO) activity, nitric oxide (NO) production and histological analysis. The effect of LGO on leukocyte migration was evaluated in vitro. Anti-oxidant activity was performed by assessing the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) in vitro. LGO pretreatment decreased significantly the levels of ALT, AST and ALP compared with APAP group. MPO activity and NO production were decreased. The histopathological analysis showed an improved of hepatic lesions in mice after LGO pretreatment. LGO inhibited neutrophil migration and exhibited anti-oxidant activity. Our results suggest that LGO has protective activity against liver toxicity induced by paracetamol.

  17. Food preservative potential of essential oils and fractions from Cymbopogon citratus, Ocimum gratissimum and Thymus vulgaris against mycotoxigenic fungi

    DEFF Research Database (Denmark)

    Nguefack, J.; Dongmo, J. B. Lekagne; Dakole, C. D.

    2009-01-01

    The food preservative potential of essential oils from three aromatic plants Cymbopogon citratus, Ocimum gratissimum and Thymus vulgaris and their fractions was investigated against two mycotoxigenic strains each of Aspergillus ochraceus, Penicillium expansum and P. verrucosum. The fungicidal...... activity was determined and expressed as a Number of Decimal Reduction of the colony forming units per ml (NDR cfu). The influence of pH variation on this activity was studied. The NDR cfu varied with the essential oils and its concentration, the pH of the medium and the strain tested. The essential oils...... from O. gratissimum exhibited the highest activity against the six fungal strains under the three pH tested. T. vulgaris and C. citratus essential oils were less active against the Penicillium species tested and A. ochraceus, respectively. Potassium sorbate did not present any activity at pH 6 and 9...

  18. Effects of Cymbopogon citratus L. essential oil on the growth, morphogenesis and aflatoxin production of Aspergillus flavus ML2-strain.

    Science.gov (United States)

    Helal, G A; Sarhan, M M; Abu Shahla, A N K; Abou El-Khair, E K

    2007-02-01

    The mycelial growth of Aspergillus flavus Link was completely inhibited using 1.5 (microl/ml or 2.0 (microl/ml of Cymbopogon citratus essential oil applied by fumigation or contact method in Czapek's liquid medium, respectively. This oil was found also to be fungicidal at the same concentrations. The sublethal doses 1.0 and 1.5 (microl/ml inhibited about 65% of fungal growth after five days of incubation and delayed conidiation as compared with the control. Microscopic observations using Light Microscope (LM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were carried out to determine the ultra structural modifications of A. flavus hyphae after treatment with C. citratus essential oil. The hyphal diameter decreased and hyphal wall appeared as precipitates and disappeared in some regions. This oil also caused plasma membrane disruption and mitochondrial structure disorganization. Moreover, Ca(+2), K(+) and Mg(+2) leakages increased from the fumigated mycelium and its total lipid content decreased, while the saturated and unsaturated fatty acids increased. One of the most important results obtained during this study was the ability of C. citratus essential oil at its sublethal dose to completely inhibit aflatoxin B(1) production from A. flavus. These findings increase the possibility of exploiting C. citratus essential oil as an effective inhibitor of biodegradation and storage contaminating fungi and also in fruit juice preservation.

  19. Treatment of oral thrush in HIV/AIDS patients with lemon juice and lemon grass (Cymbopogon citratus) and gentian violet.

    Science.gov (United States)

    Wright, S C; Maree, J E; Sibanyoni, M

    2009-03-01

    The purpose of the study was to investigate the safety and efficacy of lemon juice and lemon grass (Cymbopogon citratus) in the treatment of oral thrush in HIV/AIDS patients when compared with the control group using gentian violet aqueous solution 0.5%. Oral thrush is a frequent complication of HIV infection. In the Moretele Hospice, due to financial constraints, the treatment routinely given to patients with oral thrush is either lemon juice directly into the mouth or a lemon grass infusion made from lemon grass (Cymbopogon citratus) grown and dried at the hospice. These two remedies have been found to be very efficacious therefore are used extensively. Gentian violet, the first line medication for oral thrush in South Africa, is not preferred by the primary health clinic patients due to the visible purple stain which leads them to being stigmatized as HIV-positive. Cymbopogon citratus and Citrus limon have known antifungal properties. The study design was a randomised controlled trial. Ninety patients were randomly assigned to one of three groups: gentian violet, lemon juice or lemon grass. Inclusion criteria included being HIV-positive with a diagnosis of oral thrush. The study period was 11 days and patients were followed up every second day. International ethical principles were adhered to during the study. Of the 90 patients, 83 completed the study. In the intention-to-treat analysis, none of the p-values were significant therefore the null hypothesis could not be rejected. In the analysis of the participants who actually completed the trial, the lemon juice showed better results than the gentian violet aqueous solution 0.5% in the treatment of oral thrush in an HIV-positive population (plemon grass and gentian violet could also be rejected on the basis of the Chi-square test and the likelihood ratio test (plemon juice and lemon grass for the treatment of oral candidiasis in an HIV population was validated by the randomised controlled trial.

  20. Effects of essential oil from Cymbopogon citratus leaves and its susceptibility on the quality of fresh orange juice during storage

    Directory of Open Access Journals (Sweden)

    Euloge Adjou

    2017-03-01

    Full Text Available The present study aims to evaluate the effect of essential oil (EO from Cymbopogon citratus leaves against the spoilage flora of fresh orange juice. Thus, the EO was extracted by hydrodistillation from fresh leaves of Cymbopogon citratus collected in southern Benin and its chemical composition was determined by gas chromatography, coupled to mass spectrometry (GC/MS. Orange samples were collected from large production areas of South and Central Benin and juices were extracted by mechanical pressing. After identification of spoilage flora of fresh orange juice, antimicrobial tests were carried out with the EO of Cymbopogon citratus to evaluate its antimicrobial activity on spoilage flora of fresh orange juice.  Results indicate that the spoilage flora of fresh orange juice is mainly composed of fungi belonging to the genera of Cladosporium, Penicillium and Fusarium. Bacteria such as Enterobacter cloacae and Enterobacter aerogenes were also identified in some samples. The major compounds identified in the EO by GC/MS are Neral (33.0% and geranial (41.3% with a predominance of oxygenated monoterpenes (85.5%. Antimicrobial tests have revealed a high antibacterial activity of the EO, with minimum bactericidal concentrations (MBC between 0.1 and 0.15 μL.mL-1. Antifungal tests revealed that fungi are also susceptible to this EO with minimum fungicidal concentration (MFC between 0.15 and 0.25 μL.mL-1. Results obtained during the evaluation of the physicochemical characteristics of the orange juice stored by adding EO, indicated a significant decrease in the pH and vitamin C content. However, with EO concentration of 0.250 μL.mL-1, the pH of stored juice was 6.4 ± 0.1 after 15 days of preservation, with a best vitamin C content of 28.06 ± 0.03 mg / 100mL. The EO of Cymbopogon citratus, with high antimicrobial activity, could be used as an alternative in the preservation of fruit juices, replacing antimicrobials from chemical synthesis.

  1. Antimicrobial constituents and synergism effect of the essential oils from Cymbopogon citratus and Alpinia galanga.

    Science.gov (United States)

    Tadtong, Sarin; Watthanachaiyingcharoen, Rith; Kamkaen, Narisa

    2014-02-01

    From the fresh leaf sheathes of lemongrass (Cymbopogon citratus) and rhizomes of galanga (Alpinia galanga) light yellow and colorless oils, respectively, were obtained by hydrodistillation and microwave assisted extraction (MAE) in yields of 0.24% and 0.03%, and 0.11% and trace (w/w), respectively. By GC/MS analysis, five major constituents were identified in lemongrass oil, E-citral, Z-citral, beta-myrcene, selina-6-en-4-ol, and cis-ocimene, and five in galanga oil, 1,8-cineole, phenol 4-(2-propenyl)-acetate, dl-limonene, alpha-pinene, and a-terpineol. Three major components of the combined lemongrass and galanga oils (ratio 7:3, 1:1, 3:7) were 1,8-cineole (46.3%, 31.5%, 19.3%), E-citral (12.8%, 22.7%, 32.8%) and Z-citral (8.5%, 15.2%, 21.6%). The MICs of lemongrass and galanga oils were: against Staphylococcus aureus 0.5% and 4%, v/v, against Pseudomonas aeruginosa 40% and >40%,v/v, against Streptococcus bovis 0.25% and 0.5%, v/v, and against Candida albicans 0.25% and 0.5%, v/v. Citral (from lemongrass oil) gave greater potentiation than 1,8-cineole (from galanga oil). The combination profiles of galanga oil with lemongrass oil (volume ratios 3:7, 1:1, and 7:3) were tested against the four pathogenic microorganisms. Synergistic activity was best noted for only one ratio (volume ratio 3:7) as the sigmafic< 1 against all tested microorganisms. The present investigation provides evidenc that the utilization of two essential oils in combination should be assessed for synergistic antimicrobial activity in order to reduce their minimum effective dose.

  2. Effects of Cymbopogon citratus Stapf water extract on rat antioxidant defense system.

    Science.gov (United States)

    Somparn, Nuntiya; Saenthaweesuk, Suphaket; Naowaboot, Jarinyaporn; Thaeomor, Atcharaporn

    2014-08-01

    Cymbopogon citratus, Stapf(CCS) is commonly known as lemon grass. Previous studies showed that it has a strong antioxidant property and have been traditionally used as analgesic, antipyretic, antiseptic in SoutheastAsia. However, the effect of CCS on antioxidant defense system has not been demonstrated. The present study was conducted to investigate the effects of CCS water extract on rat antioxidant defense system, especially on the expression of y-glutamylcysteine ligase (γ-GCL) and heme oxygenase-1 (HO-1). The CCS water extract was screenedfor its phytochemical contents and antioxidant activity in vitro. Moreover, the extract was studied in rats to evaluate its effects in vivo. Male Sprague-Dawley rats aged eight weeks (250±20 g) were orally administered with CCS at 250, 500 and 1,000 mg/kg/day for one month. The extract contained flavonoids (496.17 mg gallic acid/g CCS extract) and phenolic compounds (4,020.18 mg catechin/g CCS extract). The scavenging activity (DPPH assay) of the extract was demonstrated by EC50 of 917.76±86.89 μg/ ml whereas the EC50 of the potent antioxidant, vitamin C was 31.22±1.84 μg/ml. In the animals, the protein expression of antioxidant enzymes, γGCL and HO-1 was significantly increased in the high dose-treated animals (1,000 mg/kg/day). This was consistent with elevation ofserum total antioxidant capacity. Taken together the present study provides evidence that CCS water extract exhibits antioxidant activity and antioxidant enzymes induction in vivo.

  3. Antioxidant effects of different extracts from Melissa officinalis, Matricaria recutita and Cymbopogon citratus.

    Science.gov (United States)

    Pereira, Romaiana Picada; Fachinetto, Roselei; de Souza Prestes, Alessandro; Puntel, Robson Luiz; Santos da Silva, Gloria Narjara; Heinzmann, Berta Maria; Boschetti, Ticiane Krapf; Athayde, Margareth Linde; Bürger, Marilise Escobar; Morel, Ademir Farias; Morsch, Vera Maria; Rocha, João Batista Teixeira

    2009-05-01

    Considering the important role of oxidative stress in the pathogenesis of several neurological diseases, and the growing evidence of the presence of compounds with antioxidant properties in the plant extracts, the aim of the present study was to investigate the antioxidant capacity of three plants used in Brazil to treat neurological disorders: Melissa officinalis, Matricaria recutita and Cymbopogon citratus. The antioxidant effect of phenolic compounds commonly found in plant extracts, namely, quercetin, gallic acid, quercitrin and rutin was also examined for comparative purposes. Cerebral lipid peroxidation (assessed by TBARS) was induced by iron sulfate (10 microM), sodium nitroprusside (5 microM) or 3-nitropropionic acid (2 mM). Free radical scavenger properties and the chemical composition of plant extracts were assessed by 1'-1' Diphenyl-2' picrylhydrazyl (DPPH) method and by Thin Layer Chromatography (TLC), respectively. M. officinalis aqueous extract caused the highest decrease in TBARS production induced by all tested pro-oxidants. In the DPPH assay, M. officinalis presented also the best antioxidant effect, but, in this case, the antioxidant potencies were similar for the aqueous, methanolic and ethanolic extracts. Among the purified compounds, quercetin had the highest antioxidant activity followed by gallic acid, quercitrin and rutin. In this work, we have demonstrated that the plant extracts could protect against oxidative damage induced by various pro-oxidant agents that induce lipid peroxidation by different process. Thus, plant extracts could inhibit the generation of early chemical reactive species that subsequently initiate lipid peroxidation or, alternatively, they could block a common final pathway in the process of polyunsaturated fatty acids peroxidation. Our study indicates that M. officinalis could be considered an effective agent in the prevention of various neurological diseases associated with oxidative stress.

  4. Toxicity of lemon grass Cymbopogon citratus powder and methanol extract against rice weevil Sitophilus oryzae (Coleoptera: Curculionidae

    Directory of Open Access Journals (Sweden)

    Martin Osaigbokan Uwamose

    2017-03-01

    Full Text Available Objective: To evaluate the toxicity potential of lemon grass [Cymbopogon citratus (C. citratus] products against adult rice weevil, Sitophilus oryzae. Methods: Lemon grass (C. citratus leaves were sundried for 7 days, pulverized and sieved using 0.5 mm mesh size to obtain fine powders. About 500 g of the powder were dissolved in 1000 mL of 90% methanol to produce the extract. The powder and extract were used for the bioassay. The powder was tested at 1.0, 1.5, 2.0 and 2.5 g/10 g rice grains, respectively. The toxic potential of the extract of concentration of 1.0, 1.5, 2.0, and 2.5 mg/mL were evaluated using the filter paper method. The experiment was setup on a completely randomized design using three replicates per treatment. Results: The results indicated significant difference (F = 7.450; df = 3.15; P < 0.05 in mean percentage mortality after 24, 48, 72, and 96 h exposure with the powder compared with the control. Significantly (F = 5.519; df = 3.15; P < 0.05 higher percentage adult mortality was also observed in the extract after 24, 48, 72, and 96 h exposure compared with the control. The LC50 value of the powder was 4.91 g/10 g of rice while the LT50 was 160.51 h. The LC50 value of the extract was 2.16 mg/20 mL of methanol with an LT50 of 75.10 h. The methanol extract of C. citratus showed the highest mortality compared to the powder which was less toxic. Conclusions: The study showed that C. citratus products are promising insecticides and can be used effectively in the management of Sitophilus oryzae in storage..

  5. Effect of Citrus reticulata and Cymbopogon citratus essential oils on Aspergillus flavus growth and aflatoxin production on Asparagus racemosus.

    Science.gov (United States)

    Singh, Priyanka; Shukla, Ravindra; Kumar, Ashok; Prakash, Bhanu; Singh, Shubhra; Dubey, Nawal Kishore

    2010-09-01

    Essential oils extracted from Citrus reticulata and Cymbopogon citratus were tested in vitro against the toxigenic strain of Aspergillus flavus, isolated from the tuberous roots of Asparagus racemosus, used in preparation of herbal drugs. The essential oils completely inhibited the growth of A. flavus at 750 ppm and also exhibited a broad fungitoxic spectrum against nine additional fungi isolated from the roots. Citrus reticulata and Cymbopogon citratus essential oils completely inhibited aflatoxin B(1) production at 750 and 500 ppm, respectively. During in vivo investigation, the incidence of fungi and aflatoxin B(1) production decreased considerably in essential oil-treated root samples. The findings thus indicate possible exploitation of the essential oils as effective inhibitor of aflatoxin B(1) production and as post-harvest fungitoxicant of traditionally used plant origin for the control of storage fungi. These essential oils may be recommended as plant-based antifungals as well as aflatoxin B(1) suppressors in post-harvest processing of herbal samples.

  6. Effects of Cymbopogon citratus L. essential oil on the growth, lipid content and morphogenesis of Aspergillus niger ML2-strain.

    Science.gov (United States)

    Helal, G A; Sarhan, M M; Abu Shahla, A N K; Abou El-Khair, E K

    2006-01-01

    The mycelial growth of Aspergillus niger van Tieghem was completely inhibited using 1.5 (microl/ml or 2.0 (microl/ml of Cymbopogon citratus essential oil applied by fumigation or contact method in Czapek liquid medium, respectively. This oil was found also to be fungicidal at the same concentrations. The sublethal doses 1.0 and 1.5 (microl/ml inhibited about 70% of fungal growth after five days of incubation and delayed conidiation as compared with the control. Microscopic observations using Light Microscope (LM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were carried out to determine the ultra structural modifications of A. niger hyphae after treatment with C. citratus essential oil. The hyphal diameter and hyphal wall appeared markedly thinner. This oil also caused plasma membrane disruption and mitochondrial structure disorganization. Moreover, Ca+2, K+ and Mg+2 leakages increased from the fumigated mycelium and its total lipid content decreased, while the saturated fatty acids decreased and unsaturated fatty acids increased. These findings increase the possibility of exploiting C. citratus essential oil as an effective inhibitor of biodegrading and storage contaminating fungi and in fruit juice preservation. ((c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).

  7. In vitro antimicrobial properties of plant essential oils thymus vulgaris, cymbopogon citratus and laurus nobilis against five important foodborne pathogens

    Directory of Open Access Journals (Sweden)

    Alessandra Farias Millezi

    2012-03-01

    Full Text Available Several essential oils of condiment and medicinal plants possess proven antimicrobial activity and are of important interest for the food industry. Therefore, the Minimum Inhibitory Concentrations (MIC of those oils should be determined for various bacteria. MIC varies according to the oil used, the major compounds, and the physiology of the bacterium under study. In the present study, the essential oils of the plants Thymus vulgaris (time, Cymbopogon citratus (lemongrass and Laurus nobilis (bay were chemically quantified, and the MIC was determined on the bacteria Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Listeria monocytogenes ATCC 19117, Salmonella enterica Enteritidis S64, and Pseudomonas aeruginosa ATCC 27853. The essential oil of C. citratus demonstrated bacterial activity at all concentrations tested and against all of the bacteria tested. The majority of essential oil compounds were geranial and neral. The major constituent of T. vulgaris was 1.8-cineol and of L. nobilis was linalool, which presented lower antibacterial activity, followed by 1.8-cineol. The Gram-negative bacteria demonstrated higher resistance to the use of the essential oils tested in this study. E. coli was the least sensitive and was inhibited only by the oils of C. citratus and L. nobilis.

  8. Food preservative potential of essential oils and fractions from Cymbopogon citratus, Ocimum gratissimum and Thymus vulgaris against mycotoxigenic fungi.

    Science.gov (United States)

    Nguefack, J; Dongmo, J B Lekagne; Dakole, C D; Leth, V; Vismer, H F; Torp, J; Guemdjom, E F N; Mbeffo, M; Tamgue, O; Fotio, D; Zollo, P H Amvam; Nkengfack, A E

    2009-05-31

    The food preservative potential of essential oils from three aromatic plants Cymbopogon citratus, Ocimum gratissimum and Thymus vulgaris and their fractions was investigated against two mycotoxigenic strains each of Aspergillus ochraceus, Penicillium expansum and P. verrucosum. The fungicidal activity was determined and expressed as a Number of Decimal Reduction of the colony forming units per ml (NDR cfu). The influence of pH variation on this activity was studied. The NDR cfu varied with the essential oils and its concentration, the pH of the medium and the strain tested. The essential oils from O. gratissimum exhibited the highest activity against the six fungal strains under the three pH tested. T. vulgaris and C. citratus essential oils were less active against the Penicillium species tested and A. ochraceus, respectively. Potassium sorbate did not present any activity at pH 6 and 9. At pH 3, its NDR cfu was the lowest against the six fungal strains. At the same pH and at 4000 ppm, the three essential oils presented a NRD cfu > or = 6 against strains of A. ochraceus and P. expansum. The same result was obtained with T. vulgaris and C. citratus at 8000 ppm against both strains of P. verrucosum. The highest activity of the three essential oils was recorded at pH 3 against A. ochraceus strains and at pH 9 against both species of Penicillium. From the fractionation, three active fractions were obtained each from C. citratus and O. gratissimum, and two active fractions from T. vulgaris. These active fractions exhibited a NDR cfu, two to seven folds higher than that of the complete essential oils.

  9. Effect of Lippia alba and Cymbopogon citratus essential oils on biofilms of Streptococcus mutans and cytotoxicity in CHO cells.

    Science.gov (United States)

    Tofiño-Rivera, A; Ortega-Cuadros, M; Galvis-Pareja, D; Jiménez-Rios, H; Merini, L J; Martínez-Pabón, M C

    2016-12-24

    Caries is a public health problem, given that it prevails in 60 to 90% of the school-age global population. Multiple factors interact in its etiology, among them dental plaque is necessary to have lactic acid producing microorganisms like Streptococcus from he Mutans group. Existing prevention and treatment measures are not totally effective and generate adverse effects, which is why it is necessary to search for complementary strategies for their management. The study sought to evaluate the eradication capacity of Streptococcus mutans biofilms and the toxicity on eukaryotic cells of Lippia alba and Cymbopogon citratus essential oils. Essential oils were extracted from plant material through steam distillation and then its chemical composition was determined. The MBEC-high-throughput (MBEC-HTP) (Innovotech, Edmonton, Alberta, Canada) assay used to determine the eradication concentration of S. mutans ATCC 35668 strain biofilms. Cytotoxicity was evaluated on CHO cells through the MTT cell proliferation assay. The major components in both oils were Geraniol and Citral; in L. alba 18.9% and 15.9%, respectively, and in C. citratus 31.3% and 26.7%. The L. alba essential oils presented eradication activity against S. mutans biofilms of 95.8% in 0.01mg/dL concentration and C. citratus essential oils showed said eradication activity of 95.4% at 0.1, 0.01mg/dL concentrations and of 93.1% in the 0.001mg/dL concentration; none of the concentrations of both essential oils showed toxicity on CHO cells during 24h. The L. alba and C. citratus essential oils showed eradication activity against S. mutans biofilms and null cytotoxicity, evidencing the need to conduct further studies that can identify their active components and in order to guide a safe use in treating and preventing dental caries. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  10. Extratos Cymbopogon citratus e Annona muricata como inibidores do crescimento micelial de fungos fitopatogênicos

    Directory of Open Access Journals (Sweden)

    Heloísa da Silva Bibiano

    2017-07-01

    Full Text Available Produtos alternativos vêm sendo utilizados para manejo de fitopatógenos com extratos ou óleos essenciais. A utilização de óleos essenciais é promissora para o desenvolvimento de agentes antimicrobianos por oferecer propriedades antibacterianas e antifúngicas. O presente trabalho teve por objetivo avaliar os efeitos inibitórios in vitro do óleo essencial do capim-limão (Cymbopogon citratus e do hidrolato de graviola (Annona muricata sobre desenvolvimento de fungos fitopatogênicos. Os extratos vegetais foram extraídos pela técnica de arraste a vapor e testados nas concentrações de 0,05 %, 1 %, 5 %, 10 %, 15 %, 25 %, 35 %, 45 %, 50 % e 100 %. Os fitopatógenos utilizados foram Pestalotiopsis sp., Monilinia sp. e Rhizopus spp. Todos os micro-organismos foram obtidos da coleção de micro-organismos da Universidade do Vale do Sapucaí (Univás em Pouso Alegre (MG. O óleo essencial do capim-limão inibiu o crescimento dos fungos testados nas concentrações de 50 % e 100 %. Houve inibição total do crescimento micelial de Pestalotiopsis sp. nas concentrações de 35 % a 100 %; nas concentrações abaixo de 25 %, houve inibição parcial. Com o fungo Rhizopus spp., houve crescimento parcial nas concentrações de 0,05 % a 45 %; nas concentrações de 50 % e 100 %, houve inibição total do crescimento fúngico. A Monilinia sp. obteve inibição total a partir da concentração de 35 %; abaixo da concentração de 25 %, o crescimento fúngico foi parcial. Com relação ao hidrolato da graviola (Annona muricata, os resultados indicam que não houve inibição no desenvolvimento micelial dos fungos testados, independentemente da concentração utilizada. Portanto o óleo essencial do capim-limão pode ser utilizado como alternativa ao controle desses patógenos.

  11. Repellent effects of the essential oils of Cymbopogon citratus and Tagetes minuta on the sandfly, Phlebotomus duboscqi.

    Science.gov (United States)

    Kimutai, Albert; Ngeiywa, Moses; Mulaa, Margaret; Njagi, Peter G N; Ingonga, Johnstone; Nyamwamu, Lydia B; Ombati, Cyprian; Ngumbi, Philip

    2017-02-15

    The sandfly, Phlebotomus duboscqi is a vector of zoonotic cutaneous leishmaniasis (ZCL) that is an important public health problem in Eastern Africa. Repellents have been used for protection of humans against vectors of ZCL and other vectors that transmit killer diseases including malaria, Rift Valley fever, dengue, and yellow fever. The repellent effects of different doses of the essential oils from the lemon grass, Cymbopogon citratus and Mexican marigold, Tagetes minuta were evaluated in a two-chamber bioassay against 3- to 7-day-old unfed females of P. duboscqi in the laboratory. The results were compared with those that were obtained when test animals were treated with an equivalent dose of diethyl-3-methylbenzamide, which is a repellent that is commonly used as a positive control. Overall, percentage repellency increased with increasing doses of the essential oils while biting rates decreased with increasing concentrations of the oils. Further, the oil of C. citratus was more potent than that of T. minuta with regard to protection time and biting deterrence. The effective doses at 50% (ED 50 ) and at 90% (ED 90 ) for the oil of C. citratus, were 0.04 and 0.79 mg/ml, respectively. Those of the oil of T. minuta were 0.10 and 12.58 mg/ml. In addition, the percentage repellency of 1 mg/ml of the essential oils of C. citratus and T. minuta against sandflies was 100% and 88.89%, respectively. A lower dose of 0.5 mg/ml of the oils, elicited 89.13% repellency for C. citratus and 52.22% for T. minuta. The laboratory tests showed that the essential oils of the two plants were highly repellent to adult sand flies, P. duboscqi. Thus, the two essential oils are candidate natural repellents that can be used against P. duboscqi due to their high efficacy at very low doses, hence, the envisaged safety in their use over chemical repellents. It remains to carry out clinical studies on human subjects with appropriate formulations of the oils prior to recommending their

  12. Essential oil of Cymbopogon citratus (lemongrass) and geraniol, but not citral, promote gastric healing activity in mice.

    Science.gov (United States)

    Venzon, Larissa; Mariano, Luísa Nathália Bolda; Somensi, Lincon Bordignon; Boeing, Thaise; de Souza, Priscila; Wagner, Theodoro Marcel; Andrade, Sérgio Faloni de; Nesello, Luciane Angela Nottar; da Silva, Luísa Mota

    2017-12-14

    Cymbopogon citratus, popularly known as lemongrass, is used for the treatment of gastric, nervous and hypertensive disorders, in addition to its use in the food and pharmaceutical industries. This study evaluated the gastroprotective and gastric healing effect of essential oil of C. citratus (EOCC), citral and geraniol at doses of 1-100 mg/kg (p.o) on acute ethanol-induced ulcer and chronic acetic acid-induced ulcer. Histological and histochemical evaluation was also performed, as well as the in vitro evaluation of the effects of these phytochemicals on H+/K+-ATPase activity. In the ethanol-induced gastric ulcer, the minimum effective oral dose of EOCC, citral and geraniol were 10, 100 and 3 mg/kg, reducing the ulcer area by 51.67%, 96.57% and 55.74%, respectively, compared to vehicle group (25.82 ± 3.59 mm2). Moreover, EOCC (10 mg/kg, p.o) and geraniol (3 mg/kg), but not citral (100 mg/kg), accelerated the gastric healing process by 34.52 and 80.57%, compared to acetic-acid ulcerated group treated with vehicle (36.04 ± 1.03 mm2). These healing effects were confirmed histologically by the contraction of the ulcer base and by the enhancement on mucin staining in slices of ulcer site from mice treated with EOCC or geraniol. Interestingly, EOCC and citral at 100 μg/ml inhibited the H+/ K+-ATPase activity by 28.26% and 44.36%, whereas geraniol did not change this parameter. Together, these findings confirm the gastroprotective and healing gastric ulcer effects of essential oil from aerial parts of C. citratus and added the information that geraniol, but not citral, promotes healing effects on installed ulcers. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  13. Cymbopogon citratus-synthesized gold nanoparticles boost the predation efficiency of copepod Mesocyclops aspericornis against malaria and dengue mosquitoes.

    Science.gov (United States)

    Murugan, Kadarkarai; Benelli, Giovanni; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Jeyalalitha, Tirupathi; Dinesh, Devakumar; Nicoletti, Marcello; Hwang, Jiang-Shiou; Suresh, Udaiyan; Madhiyazhagan, Pari

    2015-06-01

    Plant-borne compounds can be employed to synthesize mosquitocidal nanoparticles that are effective at low doses. However, how they affect the activity of mosquito predators in the aquatic environment is unknown. In this study, we synthesized gold nanoparticles (AuN) using the leaf extract of Cymbopogon citratus, which acted as a reducing and capping agent. AuN were characterized by a variety of biophysical methods and sorted for size in order to confirm structural integrity. C. citratus extract and biosynthesized AuN were tested against larvae and pupae of the malaria vector Anopheles stephensi and the dengue vector Aedes aegypti. LC₅₀ of C. citratus extract ranged from 219.32 ppm to 471.36 ppm. LC₅₀ of AuN ranged from 18.80 ppm to 41.52 ppm. In laboratory, the predatory efficiency of the cyclopoid crustacean Mesocyclops aspericornis against A. stephensi larvae was 26.8% (larva I) and 17% (larva II), while against A. aegypti was 56% (I) and 35.1% (II). Predation against late-instar larvae was minimal. In AuN-contaminated environment,predation efficiency against A. stephensi was 45.6% (I) and 26.7% (II), while against A. aegypti was 77.3% (I) and 51.6% (II). Overall, low doses of AuN may help to boost the control of Anopheles and Aedes larval populations in copepod-based control programs. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Growth of Cymbopogon citratus and Vetiveria zizanioides on Cu mine tailings amended with chicken manure and manure-soil mixtures: a pot scale study.

    Science.gov (United States)

    Das, Manab; Maiti, Subodh Kumar

    2009-01-01

    The Rakha Cu mines are located at East Singhbhum, Jharkhand, India and their activities ceased in 2001. The tailings (residue) were permanently stored in tailings ponds that require vegetation to reduce their impact on the environment. A pot scale study was conducted to evaluate the suitability of Cymbopogon citratus (DC.) Ex Nees and Vetiveria zizanioides (L) Nash for the reclamation of Cu tailings and to evaluate the effects of chicken manure and soil-manure mixtures on the revegetation of such tailings. Application of manure and soil-manure mixtures resulted in significant increase in pH, EC, OC, CEC and nutritional status of Cu tailings. The environmentally available and DTPA extractable Cu and Ni concentration reduced in amended tailings, while Mn and Zn content increased significantly. Plants grown on amended tailings accumulated lesser Cu and Ni but higher Mn and Zn. Plant biomass increased proportionally to manure and soil-manure mixtures application rates. Lemon grass produced more biomass than vetiver grass in either of the amended tailings. From the pot experiment, it can be suggested that application of chicken manure @ 5% (w/w) and in combination with lemon grass, could be a viable option for reclamation (phytostabilization) of toxic tailings.

  15. Antihypertensive potential of the aqueous extract which combine leaf of Persea americana Mill. (Lauraceae), stems and leaf of Cymbopogon citratus (D.C) Stapf. (Poaceae), fruits of Citrus medical L. (Rutaceae) as well as honey in ethanol and sucrose experimental model.

    Science.gov (United States)

    Dzeufiet, Paul Désiré Djomeni; Mogueo, Amélie; Bilanda, Danielle Claude; Aboubakar, Bibi-Farouck Oumarou; Tédong, Léonard; Dimo, Théophile; Kamtchouing, Pierre

    2014-12-17

    The present study was designed to evaluate the effects of the aqueous extract obtained from the mixture of fresh leaf of Persea americana, stems and fresh leaf of Cymbopogon citratus, fruits of Citrus medica and honey on ethanol and sucrose induced hypertension in rats. Rats were divided into eight groups of 6 rats each and daily treated for 5 weeks. The control group received distilled water (1 mL/kg) while rats of groups 2, 3 and 4 received ethanol 40 degrees (3 g/kg/day), 10% sucrose as drinking water and the two substances respectively. The remaining groups received in addition to sucrose and ethanol, the aqueous extract (50, 100 and 150 mg/kg) or nifedipine (10 mg/kg) respectively. Many parameters including hemodynamic, biochemical and histopathological were assessed at the end of the study. The concomitant consumption of ethanol and sucrose significantly (p < 0.001) increased the blood pressure and the heart rate compared to distilled water treated-rats. The levels of total cholesterol, LDL-cholesterol, triglycerides, atherogenic index, glucose, proteins, AST, ALT, creatinin, potassium, sodium and albumin increased while the HDL-cholesterol decreased under ethanol and sucrose feeding. Chronic ethanol and sucrose intake significantly decreased the activities of superoxide dismutase (SOD) and catalase (CAT) as well as the contents of reduced glutathione (GSH) and nitrites whereas elevated the malondialdehyde (MDA) levels. Histological analysis revealed among other vascular congestion, inflammation, tubular clarification and thickening of the vessel wall in rats treated with alcohol and sucrose. Administration of the aqueous extract or nifedipine prevented the hemodynamic, biochemical, oxidative and histological impairments induced chronic ethanol and sucrose consumption. Current results suggest that the aqueous extract used in this study possess antihypertensive activity against ethanol and sucrose induced hypertension in rats by the improvement of biochemical

  16. Toxicity and gastric tolerance of essential oils from Cymbopogon citratus, Ocimum gratissimum and Ocimum basilicum in Wistar rats.

    Science.gov (United States)

    Fandohan, P; Gnonlonfin, B; Laleye, A; Gbenou, J D; Darboux, R; Moudachirou, M

    2008-07-01

    Oils of Cymbopogon citratus, Ocimum gratissimum and Ocimum basilicum are widely used for their medicinal properties, and as food flavours and perfumes. Recently in a study in West Africa, these oils have been recommended to combat Fusarium verticillioides and subsequent fumonisin contamination in stored maize, but their toxicological profile was not investigated. The current study was undertaken to provide data on acute and subacute toxicity as well as on gastric tolerance of these oils in rat. For this purpose, the oils were given by gavage to Wistar rats for 14 consecutive days. The animals were observed daily for their general behaviour and survival, and their visceral organs such as stomach and liver were taken after sacrifice for histological analyses. A dose-dependent effect of the tested oils was observed during the study. Applied at doses generally higher than 1500 mg/kg body weight, the oils caused significant functional damages to stomach and liver of rat. Unlike the other oils, administration of O. gratissimum oil did not result in adverse effects in rat liver at the tested doses. The no observed adverse effect level (NOAEL) of the tested oils has been established. The three tested oils can be considered as safe to human when applied on stored maize at recommended concentrations.

  17. Flavan hetero-dimers in the Cymbopogon citratus infusion tannin fraction and their contribution to the antioxidant activity.

    Science.gov (United States)

    Costa, Gustavo; González-Manzano, Susana; González-Paramás, Ana; Figueiredo, Isabel Vitória; Santos-Buelga, Celestino; Batista, Maria Teresa

    2015-03-01

    Cymbopogon citratus (lemongrass) leaf infusion, a commonly used ingredient in Asian, African and Latin American cuisines, is also used in traditional medicine for the treatment of several pathological conditions; however, little is known about their bioactive compounds. Recent studies revealed the crucial role of the phenolic compounds namely flavonoids and tannins on the infusion bioactivity. Flavonoids have already been characterized; however the tannin fraction of lemongrass infusion is still uncharted. The aim of the present work is to characterize this fraction, and to evaluate its contribution to the antioxidant potential of this plant. Chemical characterization was achieved by HPLC-DAD-ESI/tandem MS and the antioxidant activity was evaluated using DPPH, ABTS and FRAP assays. Hetero-dimeric flavan structures have been described for the first time in lemongrass consisting of apigeniflavan or luteoliflavan units linked to a flavanone, either naringenin or eriodictyol, which may occur as aglycone or glycosylated forms. The antioxidant capacity of the fraction containing these compounds was significantly higher than the infusion, indicating its potential as a source of natural antioxidants.

  18. Inhibitory effect of three C-glycosylflavonoids from Cymbopogon citratus (Lemongrass) on human low density lipoprotein oxidation.

    Science.gov (United States)

    Orrego, Roxana; Leiva, Elba; Cheel, José

    2009-09-30

    This study assessed the inhibitory effect of three C-glycosylflavonoids from Cymbopogon citratus leaves--isoorientin (1), swertiajaponin (2) and isoorientin 2"-Orhamnoside (3)--on human LDL oxidation. Isolated LDL was incubated with compounds 1-3 and the kinetics of lipid peroxidation were assessed by conjugated diene and malondialdehyde-thiobarbituric acid reactive substances (MDA-TBARS) formation after addition of copper ions. Significant differences (p < 0.05) between the lag time phase of the control and the lag time phase in the presence of the compounds 1 (0.25 microM) and 2 (0.50 microM) were observed. After five hours of incubation all three compounds showed a significant inhibitory effect on MDA-TBARS formation with respect to the control. After six hours of incubation only compound 1 kept a remarkable antioxidant effect. This study demonstrates that isoorientin (1) is an effective inhibitor of in vitro LDL oxidation. As oxidative damage to LDL is a key event in the formation of atherosclerotic lesions, the use of this natural antioxidant may be beneficial to prevent or attenuate atherosclerosis.

  19. A novel ionic amphiphilic chitosan derivative as a stabilizer of nanoemulsions: Improvement of antimicrobial activity of Cymbopogon citratus essential oil.

    Science.gov (United States)

    Bonferoni, Maria Cristina; Sandri, Giuseppina; Rossi, Silvia; Usai, Donatella; Liakos, Ioannis; Garzoni, Alice; Fiamma, Maura; Zanetti, Stefania; Athanassiou, Athanassia; Caramella, Carla; Ferrari, Franca

    2017-04-01

    Amphiphilic chitosans have been recently proposed to improve delivery of poorly soluble drugs. In the present paper a derivative obtained by ionic interaction between chitosan and oleic acid was for the first time studied to physically stabilize o/w nanoemulsions of an antimicrobial essential oil, Cymbopogon citratus (Lemongrass), in a low energy and mild conditions emulsification process. The novel combination of spontaneous emulsification process with chitosan oleate amphiphilic properties resulted in a stable dispersion of a few hundred nanometer droplets. Positive zeta potential confirmed the presence of a chitosan shell around the oil droplets, which is responsible for the nanoemulsion physical stabilization and for the maintenance of chitosan bioactive properties, such as mucoadhesion. Cytotoxicity test was performed on four different cell lines (HEp-2, Caco-2, WKD and McCoy cells) showing biocompatibility of the system. The maintenance and in some cases even a clear improvement in the essential oil antimicrobial activity towards nine bacterial and ten fungal strains, all of clinical relevance was verified for Lemongrass nanoemulsion. Copyright © 2017. Published by Elsevier B.V.

  20. Efecto del aceite esencial de Cymbopogon citratus sobre propiedades fisicoquímicas en películas de quitosano

    Directory of Open Access Journals (Sweden)

    María del Carmen Vázquez - Briones

    2017-01-01

    Full Text Available Se investigó el efecto de la incorporación de aceite esencial de zacate limón ( Cymbopogon citratus , en concentraciones de 0, 200 y 400 ppm, en las propiedades fisicoquímicas (espesor, humedad, solubilidad, permeabilidad al vapor de agua, color, transparencia y mecánicas (resistencia a la tensión y elongación de películas de quitosano a dos concentraciones (1 y 3%. Los resultados mostraron un efecto significativo (p ≤ 0,05 en los valores del espesor de las películas a las dos concentraciones de quitosano. Se observó un efecto significativo (p ≤ 0,05 en los valores de humedad a concentraciones de 0, 200 y 400 ppm de aceite esencial. La adición de aceite esencial en películas de quitosano mostró un efecto significativo (p ≤ 0,05 en los valores de permeabili dad al vapor de agua. La concentración de quitosano mostró un efecto significativo (p ≤ 0,05 en transparencia y en los parámetros de color L* , a* , b* . Al variar la concentración de quitosano se observó un incremento significativo (p ≤ 0,05 en los valores de resistencia a la tensión de las películas de quitosano.

  1. In vitro antimicrobial properties of plant essential oils thymus vulgaris, cymbopogon citratus and laurus nobilis against five important foodborne pathogens Propriedades antibacterianas in vitro de óleos essenciais de thymus vulgaris, cymbopogon citratus e laurus nobilis contra cinco importantes bactérias patogênicas veiculadas por alimentos

    OpenAIRE

    Alessandra Farias Millezi; Danila Soares Caixeta; Diogo Francisco Rossoni; Maria das Graças Cardoso; Roberta Hilsdorf Piccoli

    2012-01-01

    Several essential oils of condiment and medicinal plants possess proven antimicrobial activity and are of important interest for the food industry. Therefore, the Minimum Inhibitory Concentrations (MIC) of those oils should be determined for various bacteria. MIC varies according to the oil used, the major compounds, and the physiology of the bacterium under study. In the present study, the essential oils of the plants Thymus vulgaris (time), Cymbopogon citratus (lemongrass) and Laurus nobili...

  2. Monoterpenic aldehydes as potential anti-Leishmania agents: activity of Cymbopogon citratus and citral on L. infantum, L. tropica and L. major.

    Science.gov (United States)

    Machado, M; Pires, P; Dinis, A M; Santos-Rosa, M; Alves, V; Salgueiro, L; Cavaleiro, C; Sousa, M C

    2012-03-01

    In order to contribute for the search of new drugs for leishmaniasis, we study the susceptibility of Leishmania infantum, Leishmania tropica and Leishmania major to Cymbopogon citratus essential oil and major compounds, mrycene and citral. C. citratus and citral were the most active inhibiting L. infantum, L. tropica and L. major growth at IC(50) concentrations ranging from 25 to 52 μg/ml and from 34 to 42 μg/ml, respectively. L. infantum promastigotes exposed to essential oil and citral underwent considerable ultrastructural alterations, namely mitochondrial and kinetoplast swelling, autophagosomal structures, disruption of nuclear membrane and nuclear chromatin condensation. C. citratus essential oil and citral promoted the leishmanicidal effect by triggering a programmed cell death. In fact, the leishmanicidal activity was mediated via apoptosis as evidenced by externalization of phosphatidylserine, loss of mitochondrial membrane potential, and cell-cycle arrest at the G(0)/G(1) phase. Taken together, ours findings lead us to propose that citral was responsible for anti-Leishmania activity of the C. citratus and both may represent a valuable source for therapeutic control of leishmaniasis. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Activity of Ocimum basilicum, Ocimum canum, and Cymbopogon citratus essential oils against Plasmodium falciparum and mature-stage larvae of Anopheles funestus s.s.

    Science.gov (United States)

    Akono Ntonga, Patrick; Baldovini, Nicolas; Mouray, Elisabeth; Mambu, Lengo; Belong, Philippe; Grellier, Philippe

    2014-01-01

    The biological activities of essential oils from three plants grown in Cameroon: Ocimum basilicum, Ocimum canum, and Cymbopogon citratus were tested against Plasmodium falciparum and mature-stage larvae of Anopheles funestus. Gas chromatography and gas chromatography - mass spectrometry analyses showed that the main compounds are geranial, 1,8-cineole and linalool in C. citratus, O. canum and O. basilicum, respectively. Larvicidal tests carried out according to the protocol recommended by the World Health Organization showed that the essential oil of leaves of C. citratus is the most active against larvae of An. funestus (LC50 values = 35.5 ppm and 34.6 ppm, respectively, for larval stages III and IV after 6 h of exposure). Besides, the in vitro anti-plasmodial activity evaluated by the radioisotopic method showed that the C. citratus oil is the most active against P. falciparum, with an IC50 value of 4.2 ± 0.5 μg/mL compared with O. canum (20.6 ± 3.4 μg/mL) and O. basilicum (21 ± 4.6 μg/mL). These essential oils can be recommended for the development of natural biocides for fighting the larvae of malaria vectors and for the isolation of natural products with anti-malarial activity. © P. Akono Ntonga et al., published by EDP Sciences, 2014.

  4. Use of dimethyldioxirane in the epoxidation of the main constituents of the essential oils obtained from Tagetes lucida, Cymbopogon citratus, Lippia alba and Eucalyptus citriodora.

    Science.gov (United States)

    Veloza, Luz A; Orozco, Lina M; Sepúlveda-Arias, Juan C

    2011-07-01

    Dimethyldioxirane (DMDO), a widely used oxidant in organic synthesis is considered an environmentally friendly oxygen transfer reagent because acetone is the only byproduct formed in its oxidation reactions. This work describes the isolation of the main constituents (terpenes) in the essential oils obtained from Tagetes lucida, Cymbopogon citratus, Lippia alba and Eucalyptus citriodora, their epoxidation with DMDO in acetone solution and the characterization of the resulting epoxides by GC-MS (EI) and NMR. This is one of the first reports involving the application of dioxirane chemistry to essential oils in order to generate modified compounds with potential uses in several areas of medicine and industry.

  5. Phytochemical composition of Cymbopogon citratus and Eucalyptus citriodora essential oils and their anti-inflammatory and analgesic properties on Wistar rats.

    Science.gov (United States)

    Gbenou, Joachin D; Ahounou, Judith F; Akakpo, Huguette B; Laleye, Anatole; Yayi, Eléonore; Gbaguidi, Fernand; Baba-Moussa, Lamine; Darboux, Raphael; Dansou, Pierre; Moudachirou, Mansourou; Kotchoni, Simeon O

    2013-02-01

    Cymbopogon citratus and Eucalyptus citriodora are widely used herbs/plants as a source of ethnomedicines in tropical regions of the world. In this work, we studied the anti-inflammatory and gastroprotective effects of C. citratus and E. citriodora essential oils on formol-induced edema, and acetic acid induced abdominal cramps in Wistar rats. To fully understand the chemically induced anti-inflammatory properties of these plants, we first analyzed the chemical composition of the essential oils. A total of 16 chemical constituents accounting for 93.69 % of the oil, were identified in C. citratus among which, Geranial (27.04 %), neral (19.93 %) and myrcene (27.04 %) were the major constituents. For E. citriodora, 19 compounds representing 97.2 % of the extracted oil were identified. The dominant compound of E. citriodora essential oil was citronellal (83.50 %). In vivo analysis and histological assay showed that the two essential oils displayed significant dose dependent edema inhibition effect over time. They displayed strong analgesic and antipyretic properties similar to that induced by 50 mg/kg of acetylsalicylate of lysine. However, the E. citriodora essential oil was more effective than that of C. citratus. We identified significant numbers of aldehyde molecules in both essential oils mediating antioxidant activity that may contribute to the anti-inflammatory effects observed on the rats. Altogether, this work demonstrates the anti-inflammatory property of C. citratus and E. citriodora suggesting their potential role as adjuvant therapeutic alternatives in dealing with inflammatory-related diseases.

  6. Chemical Composition of Essential Oils from Thymus vulgaris, Cymbopogon citratus, and Rosmarinus officinalis, and Their Effects on the HIV-1 Tat Protein Function.

    Science.gov (United States)

    Feriotto, Giordana; Marchetti, Nicola; Costa, Valentina; Beninati, Simone; Tagliati, Federico; Mischiati, Carlo

    2017-12-28

    New drugs would be beneficial to fight resistant HIV strains, in particular those capable of interfering with essential viral functions other than those targeted by highly active antiretroviral therapy drugs. Despite the central role played by Tat protein in HIV transcription, a search for vegetable extracts able to hamper this important viral function was never carried out. In this work, we evaluated the chemical composition and possible interference of essential oil from Thymus vulgaris, Cananga odorata, Cymbopogon citratus, and Rosmarinus officinalis with the Tat/TAR-RNA interaction and with Tat-induced HIV-1 LTR transcription. GC/MS Analysis demonstrated the biodiversity of herbal species translated into essential oils composed of different blends of terpenes. In all of them, 4 - 6 constituents represent from 81.63% to 95.19% of the total terpenes. Essential oils of Thymus vulgaris, Cymbopogon citratus, and Rosmarinus officinalis were active in interfering with Tat functions, encouraging further studies to identify single terpenes responsible for the antiviral activity. In view of the quite different composition of these essential oils, we concluded that their interference on Tat function depends on specific terpene or a characteristic blend. © 2018 Wiley-VHCA AG, Zurich, Switzerland.

  7. Effect of Organic Manures on the Growth of Cymbopogon citratus and Chrysopogon zizanioides for the Phytoremediation of Chromite-Asbestos Mine Waste: A Pot Scale Experiment.

    Science.gov (United States)

    Kumar, Adarsh; Maiti, Subodh Kumar

    2015-01-01

    The abandoned chromite-asbestos mines are located in the Roro hills, West Singhbhum, Jharkhand, India, where mining operation ceased in 1983, and since then these mines are causing environmental pollution. The present study was planned to phytoremediate these metalloid and metal contaminated mine waste by using two aromatic grasses, Cymbopogon citratus and Chrysopogon zizanioides by applying different proportions of amendments (chicken manure, farmyard manure and garden soil). Mine waste has neutral pH, low electrical conductivity and organic carbon with higher concentration of total metals (Cr and Ni) as compared to soil. Application of manures resulted significant improvements of mine waste characteristics and plant growth, reduction in the availability of total extractable toxic metals (Cr, Ni) and increase in Mn, Zn and Cu concentration in the substrate. The maximum growth and biomass production for C. citratus and C. zizanioides were found in T-IV combination comprising of mine waste (90%), chicken manure (2.5%), farmyard manure (2.5%) and garden soil (5%). Addition of T-IV combination also resulted in low Cr and Ni accumulation in roots and reduction in translocation to shoots. Study indicates that C. citratus and C. zizanioides can be used for phytostabilization of abandoned chromite-asbestos mine waste with amendments.

  8. Housefly (Musca domestica L.) control potential of Cymbopogon citratus Stapf. (Poales: Poaceae) essential oil and monoterpenes (citral and 1,8-cineole).

    Science.gov (United States)

    Kumar, Peeyush; Mishra, Sapna; Malik, Anushree; Satya, Santosh

    2013-01-01

    In spite of being a major vector for several domestic, medical, and veterinary pests, the control aspect of the common housefly, Musca domestica L. (Diptera: Muscidae) is often neglected. In the present study, the essential oil of Cymbopogon citratus and its major components were evaluated for control of housefly. The chemical composition analysis of C. citratus oil by gas chromatographic mass spectrometry (GC-MS) revealed citral (47 %) and 1,8-cineole (7.5 %) as principal components. The analysis of oil vapor by solid phase microextraction (SPME/GC-MS) showed increase in citral (74.9 %) and 1,8-cineole (8.6 %) content. Assay of oil against housefly larvae and pupae through contact toxicity assay showed lethal concentration (LC)(50) value of 0.41 μl/cm(2) and of percentage inhibition rate (PIR) of 77.3 %, respectively. Fumigation assay was comparatively more effective with LC(50) of 48.6 μl/L against housefly larvae, and a PIR value of 100 % against housefly pupae. The monoterpenes, citral, and 1,8-cineole, when assessed for their insecticidal activity against housefly larvae, showed LC(50) of 0.002 and 0.01 μl/cm(2) (contact toxicity assay) and LC(50) of 3.3 and 2.4 μl/L (fumigation assay). For pupicidal assay, both citral and 1,8-cineole had a PIR value of 100 %. High efficacy of citral and 1,8-cineole against housefly, established them to be an active insecticidal agent of C. citratus oil. The study demonstrates potentiality of C. citratus oil as an excellent insecticide for housefly control, and the results open up the opportunity of oil/monoterpenes being developed into an eco-friendly, economical, and acceptable product.

  9. Cymbopogon citratus as source of new and safe anti-inflammatory drugs: bio-guided assay using lipopolysaccharide-stimulated macrophages.

    Science.gov (United States)

    Francisco, Vera; Figueirinha, Artur; Neves, Bruno Miguel; García-Rodríguez, Carmen; Lopes, Maria Celeste; Cruz, Maria Teresa; Batista, Maria Teresa

    2011-01-27

    Aqueous extracts of Cymbopogon citratus (Cy) leaves are used in traditional medicine for the treatment of inflammatory conditions, however, little is known about their mechanism of action. The aim of this study is to explore the anti-inflammatory properties of Cymbopogon citratus leaves and their polyphenol-rich fractions (PFs), as well its mechanism of action in murine macrophages. A lipid- and essential oil-free infusion of Cy leaves was prepared (Cy extract) and fractionated by column chromatography. Anti-inflammatory properties of Cy extract (1.115 mg/ml) and its PFs, namely phenolic acids (530 μg/ml), flavonoids (97.5 μg/ml) and tannins (78 μg/ml), were investigated using lipopolysaccharide (LPS)-stimulated Raw 264.7 macrophages as in vitro model. As inflammatory parameters, nitric oxide (NO) production was evaluated by Griess reaction, as well as effects on cyclooxygenase-2 (COX-2), inducible NO synthase (iNOS) expression and on intracellular signaling pathways activation, which were analyzed by Western blot using specific antibodies. Cy extract inhibited iNOS expression, NO production and various LPS-induced pathways like p38 mitogen-activated protein kinase (MAPK), c-jun NH(2)-terminal kinase (JNK) 1/2 and the transcription nuclear factor (NF)-κB. The extracellular signal-regulated kinase (ERK) 1/2 and the phosphatidylinositol-3-kinase (PI3K)/Akt activation were not affected by Cy extract. Both phenolic acid- and tannin-rich fractions significantly inhibited NF-κB activation, iNOS expression and NO production but none of the PFs modulated MAPKs or PI3K/Akt activation. Neither Cy extract nor PFs affected LPS-induced COX-2 expression but LPS-induced PGE(2) production is inhibited by Cy extract and by phenolic acid-rich fraction. Our data provide evidence that support the usage of Cymbopogon citratus leaves extract in traditional medicine, and suggest that Cy, in particular its polyphenolic compounds, could constitute a natural source of a new and safe

  10. Conversion of natural aldehydes from Eucalyptus citriodora, Cymbopogon citratus, and Lippia multiflora into oximes: GC-MS and FT-IR analysis.

    Science.gov (United States)

    Ouédraogo, Igor W; Boulvin, Michael; Flammang, Robert; Gerbaux, Pascal; Bonzi-Coulibaly, Yvonne L

    2009-08-31

    Three carbonyl-containing extracts of essential oils from Eucalyptus citriodora (Myrtaceae), Cymbopogon citratus (Gramineae) and Lippia multiflora (Verbenaceae) were used for the preparation of oximes. The reaction mixtures were analyzed by GC-MS and different compounds were identified on the basis of their retention times and mass spectra. We observed quantitative conversion of aldehydes to their corresponding oximes with a purity of 95 to 99%. E and Z stereoisomers of the oximes were obtained and separated by GC-MS. During GC analysis, the high temperature in the injector was shown to cause partial dehydratation of oximes and the resulting nitriles were readily identified. Based on FT-IR spectroscopy, that revealed the high stability and low volatility of these compounds, the so-obtained oximes could be useful for future biological studies.

  11. Conversion of Natural Aldehydes from Eucalyptus citriodora, Cymbopogon citratus, and Lippia multiflora into Oximes: GC-MS and FT-IR Analysis †

    Directory of Open Access Journals (Sweden)

    Igor W. Ouédraogo

    2009-08-01

    Full Text Available Three carbonyl-containing extracts of essential oils from Eucalyptus citriodora (Myrtaceae, Cymbopogon citratus (Gramineae and Lippia multiflora (Verbenaceae were used for the preparation of oximes. The reaction mixtures were analyzed by GC-MS and different compounds were identified on the basis of their retention times and mass spectra. We observed quantitative conversion of aldehydes to their corresponding oximes with a purity of 95 to 99%. E and Z stereoisomers of the oximes were obtained and separated by GC-MS. During GC analysis, the high temperature in the injector was shown to cause partial dehydratation of oximes and the resulting nitriles were readily identified. Based on FT-IR spectroscopy, that revealed the high stability and low volatility of these compounds, the so-obtained oximes could be useful for future biological studies.

  12. Suppression of oxidative stress and pro-inflammatory mediators by Cymbopogon citratus D. Stapf extract in lipopolysaccharide stimulated murine alveolar macrophages.

    Science.gov (United States)

    Tiwari, M; Dwivedi, U N; Kakkar, P

    2010-10-01

    Exploration of antioxidants of plant origin and their scientific validation for their immense pharmacological potential is emerging as an issue of intense research now-a-days.The effect of Cymbopogon citratus extract was seen on cell viability, oxidative stress markers i.e. ROS production, SOD activity, lipid peroxidation and GSH content of murine alveolar macrophages stressed with lipopolysaccharide. Modulation in release of NO and pro-inflammatory cytokine TNF-α along with alterations in mitochondrial membrane potential under stress were compared with known plant derived antioxidant quercetin. The extract was not found to be cytotoxic at any of the selected doses. At 5 and 10 μg the extract showed significant increase in SOD activity, GSH content (pcitratus in the form of dietary component and also in formulations against lung inflammatory diseases where oxidative stress plays an important role. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Elaboración y estandarización de microencapsulados de aceites esenciales de hierba luisa (Cymbopogon citratus) y hojas de ishpink (Ocotea quixos) como aditivos nutricionales para piscicultura

    OpenAIRE

    Caicedo de la Cruz, Diego Javier; Chamba Sánchez, María Natali

    2016-01-01

    The research was conducted in the laboratories of Centro de Investigación y Valoración de la Biodiversidad CIVABI of Universidad Politécnica Salesiana which consisted of microencapsulating essential oils of Lemon grass (Cymbopogon citratus) and Ishpink (Ocotea quixos) under the technic of ionic gels for a future application in pisciculture, as a supplement in pet food diets. The essential oils obtained from “Fundación Chankuap” located in the city of Macas, province o...

  14. In vitro antimicrobial properties of plant essential oils thymus vulgaris, cymbopogon citratus and laurus nobilis against five important foodborne pathogens Propriedades antibacterianas in vitro de óleos essenciais de thymus vulgaris, cymbopogon citratus e laurus nobilis contra cinco importantes bactérias patogênicas veiculadas por alimentos

    Directory of Open Access Journals (Sweden)

    Alessandra Farias Millezi

    2012-03-01

    Full Text Available Several essential oils of condiment and medicinal plants possess proven antimicrobial activity and are of important interest for the food industry. Therefore, the Minimum Inhibitory Concentrations (MIC of those oils should be determined for various bacteria. MIC varies according to the oil used, the major compounds, and the physiology of the bacterium under study. In the present study, the essential oils of the plants Thymus vulgaris (time, Cymbopogon citratus (lemongrass and Laurus nobilis (bay were chemically quantified, and the MIC was determined on the bacteria Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Listeria monocytogenes ATCC 19117, Salmonella enterica Enteritidis S64, and Pseudomonas aeruginosa ATCC 27853. The essential oil of C. citratus demonstrated bacterial activity at all concentrations tested and against all of the bacteria tested. The majority of essential oil compounds were geranial and neral. The major constituent of T. vulgaris was 1.8-cineol and of L. nobilis was linalool, which presented lower antibacterial activity, followed by 1.8-cineol. The Gram-negative bacteria demonstrated higher resistance to the use of the essential oils tested in this study. E. coli was the least sensitive and was inhibited only by the oils of C. citratus and L. nobilis.Diversos óleos essenciais de plantas condimentares e medicinais possuem atividade antimicrobiana comprovada, sendo de grande interesse para a indústria de alimentos. Dessa forma, as Concentrações Mínimas Inibitórias (CMI desses óleos para diversas bactérias devem ser determinadas. As CMI variam de acordo com o óleo utilizado, dos compostos majoritários e da fisiologia da bactéria em estudo. Na presente pesquisa, os óleos essenciais das plantas Thymus vulgaris (tomilho, Cymbopogon citratus (capim-limão e Laurus nobilis (louro foram quantificados quimicamente e determinou-se a CMI sobre as bactérias Staphylococcus aureus ATCC 25923, Escherichia. coli

  15. Effect of Cymbopogon citratus (lemongrass) and Syzygium aromaticum (clove) oils on the morphology and mortality of Aedes aegypti and Anopheles dirus larvae.

    Science.gov (United States)

    Soonwera, Mayura; Phasomkusolsil, Siriporn

    2016-04-01

    Cymbopogon citratus (lemongrass) and Syzygium aromaticum (clove) oils were evaluated to determine mortality rates, morphological aberrations, and persistence when used against third and fourth larval instars of Aedes aegypti and Anopheles dirus. The oils were evaluated at 1, 5, and 10 % concentrations in mixtures with soybean oil. Persistence of higher concentrations was measured over a period of 10 days. For Ae. aegypti, both plant oils caused various morphological aberrations to include deformed larvae, incomplete eclosion, white pupae, deformed pupae, dead normal pupae, and incomplete pupal eclosion. All of these aberrations led to larval mortality. In Ae. aegypti larvae, there were no significant differences in mortality at days 1, 5, and 10 or between third and fourth larval instar exposure. In An. dirus, morphological aberrations were rare and S. aromaticum oil was more effective in causing mortality among all larval stages. Both oils were equally effective at producing mortality on days 1, 5, and 10. Both oils had slightly increased LT50 rates from day 1 to day 10. In conclusion, both lemongrass and clove oils have significant effects on the immature stages of Ae. aegypti and An. dirus and could potentially be developed for use as larvicides.

  16. Angolan Cymbopogon citratus used for therapeutic benefits: nutritional composition and influence of solvents in phytochemicals content and antioxidant activity of leaf extracts.

    Science.gov (United States)

    Soares, Marta O; Alves, Rita C; Pires, Pedro C; Oliveira, M Beatriz P P; Vinha, Ana F

    2013-10-01

    Folk medicine is a relevant and effective part of indigenous healthcare systems which are, in practice, totally dependent on traditional healers. An outstanding coincidence between indigenous medicinal plant uses and scientifically proved pharmacological properties of several phytochemicals has been observed along the years. This work focused on the leaves of a medicinal plant traditionally used for therapeutic benefits (Angolan Cymbopogon citratus), in order to evaluate their nutritional value. The bioactive phytochemical composition and antioxidant activity of leaf extracts prepared with different solvents (water, methanol and ethanol) were also evaluated. The plant leaves contained ∼60% of carbohydrates, protein (∼20%), fat (∼5%), ash (∼4%) and moisture (∼9%). The phytochemicals screening revealed the presence of tannins, flavonoids, and terpenoids in all extracts. Methanolic extracts also contained alkaloids and steroids. Several methods were used to evaluate total antioxidant capacity of the different extracts (DPPH·, NO·, and H₂O₂ scavenging assays, reducing power, and FRAP). Ethanolic extracts presented a significantly higher antioxidant activity (pextracts. Methanolic extracts showed the lowest radical scavenging activities for both DPPH· and NO· radicals. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Cholesterol reduction and lack of genotoxic or toxic effects in mice after repeated 21-day oral intake of lemongrass (Cymbopogon citratus) essential oil.

    Science.gov (United States)

    Costa, Celso A R A; Bidinotto, Lucas T; Takahira, Regina K; Salvadori, Daisy M F; Barbisan, Luís F; Costa, Mirtes

    2011-09-01

    Cymbopogon citratus (lemongrass) is currently used in traditional folk medicine. Although this species presents widespread use, there are no scientific data on its efficacy or safety after repeated treatments. Therefore, this work investigated the toxicity and genotoxicity of this lemongrass's essential oil (EO) in male Swiss mice. The single LD(50) based on a 24h acute oral toxicity study was found to be around 3500 mg/kg. In a repeated-dose 21-day oral toxicity study, mice were randomly assigned to two control groups, saline- or Tween 80 0.01%-treated groups, or one of the three experimental groups receiving lemongrass EO (1, 10 or 100mg/kg). No significant changes in gross pathology, body weight, absolute or relative organ weights, histology (brain, heart, kidneys, liver, lungs, stomach, spleen and urinary bladder), urinalysis or clinical biochemistry were observed in EO-treated mice relative to the control groups. Additionally, blood cholesterol was reduced after EO-treatment at the highest dose tested. Similarly, data from the comet assay in peripheral blood cells showed no genotoxic effect from the EO. In conclusion, our findings verified the safety of lemongrass intake at the doses used in folk medicine and indicated the beneficial effect of reducing the blood cholesterol level. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Preventive efficacy of hydroalcoholic extract of Cymbopogon citratus against radiation-induced DNA damage on V79 cells and free radical scavenging ability against radicals generated in vitro.

    Science.gov (United States)

    Rao, B S S; Shanbhoge, R; Rao, B N; Adiga, S K; Upadhya, D; Aithal, B K; Kumar, M R S

    2009-04-01

    This study presents the findings of free radical scavenging and antigenotoxic effect of hydroalcoholic extract of Cymbopogon citratus (CCE). The CCE at a concentration of 60 microg/mL resulted in a significant scavenging ability of 2,2-diphenyl-2-picryl hydrazyl (DPPH; (85%), 2,2-azinobis (3-ethyl benzothiazoline-6-sulphonic acid) (ABTS; 77%), hydroxyl (70%), superoxide (76%), nitric oxide (78%) free radicals generated using in vitro and also a moderate anti-lipid peroxidative effect (57%). Further, the radiation-induced antigenotoxic potential of CCE was assessed in Chinese hamster lung fibroblast cells (V79) using micronucleus assay. The CCE resulted in a dose-dependent decrease in the yield of radiation-induced micronuclei, with a maximum effect at 125 microg/mL CCE for 1 h before 2 Gy of radiation. Similarly, there was a significant (P < 0.05-0.0001) decrease in percentage of micronuclei when V79 cells were treated with optimal dose of CCE (125 microg/mL) before exposure to different doses of gamma radiation, that is, 0.5-4 Gy, compared with radiation alone groups. The results of the micronucleus study indicated antigenotoxic effect demonstrating the radioprotective potential of CCE and, which may partly due to its and antioxidant capacity as it presented its ability to scavenge various free radicals in vitro and anti-lipid peroxidative potential.

  19. Potential antioxidant and cytoprotective effects of essential oil extracted from Cymbopogon citratus on OxLDL and H2O2 LDL induced Human Peripheral Blood Mononuclear Cells (PBMC

    Directory of Open Access Journals (Sweden)

    Jamuna S.

    2017-06-01

    Full Text Available Cymbopogon citratus (lemon grass is commonly used in traditional folk medicine. The essential oil extracted from C. citratus has been reported as a potential anti-oxidant and anti-inflammatory agent. This study has been designed to explore the protective effect of C. citratus (lemon grass against modified LDL (OxLDL and H2O2 LDL induced cytotoxicity in Peripheral Blood Mononuclear Cells (PBMC. The essential oil extracted from C. citratus (EOC was subjected to FT-IR spectroscopic analysis for the identification of functional groups. In vitro antioxidant assays were carried out to assess the electron donating capability of EOC as compared with a known standard L-ascorbic acid. The cytoprotective effects of EOC were determined in PBMC induced with modified LDL. Spectra obtained from FT-IR analysis showed the presence of functional groups in EOC such as H-bonded, OH stretching, NH stretching, aldehydeCH stretching, aldehyde/ketoneCO stretching, CC-stretching, CH3 bending, CH in plane bending. EOC has greater antioxidant property when compared with the standard L-ascorbic acid. EOC at all test concentrations demonstrated free radical scavenging activity and cytoprotective effect when challenged against modified LDL in PBMC. The above results show EOC as a promising antioxidant and cytoprotective agent.

  20. Liquid and vapour-phase antifungal activities of selected essential oils against candida albicans: microscopic observations and chemical characterization of cymbopogon citratus

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    Malik Anushree

    2010-11-01

    Full Text Available Abstract Background Use of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil. Methods Minimum Inhibitory concentration (MIC of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM/Atomic force microscopy (AFM and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS. Results Lemon grass (Cymbopogon citratus essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita and eucalyptus (Eucalyptus globulus essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l was significantly higher than that in the vapour phase (32.7 mg/l and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%; α-citral or geranial (36.2% and β-citral or neral (26.5%, monoterpene hydrocarbons (7.9% and sesquiterpene hydrocarbons (3.8%. Conclusion Lemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious

  1. Liquid and vapour-phase antifungal activities of selected essential oils against Candida albicans: microscopic observations and chemical characterization of Cymbopogon citratus.

    Science.gov (United States)

    Tyagi, Amit K; Malik, Anushree

    2010-11-10

    Use of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil. Minimum Inhibitory concentration (MIC) of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM)/Atomic force microscopy (AFM) and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS. Lemon grass (Cymbopogon citratus) essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita) and eucalyptus (Eucalyptus globulus) essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l) was significantly higher than that in the vapour phase (32.7 mg/l) and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%); α-citral or geranial (36.2%) and β-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%). Lemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious morphological changes in cellular structures and cell

  2. The anti-allergic activity of Cymbopogon citratus is mediated via inhibition of nuclear factor kappa B (Nf-Κb) activation.

    Science.gov (United States)

    Santos Serafim Machado, Marta; Ferreira Silva, Hugo Bernardino; Rios, Raimon; Pires de Oliveira, Anaque; Vilany Queiroz Carneiro, Noma; Santos Costa, Ryan; Santos Alves, William; Meneses Souza, Fabio-Luis; da Silva Velozo, Eudes; Alves de Souza, Silvana; Sarmento Silva, Tania Maria; Silva, Maria Lenise; Pontes-de-Carvalho, Lain Carlos; Alcântara-Neves, Neuza Maria; Figueiredo, Camila Alexandrina

    2015-06-06

    The prevalence of allergic diseases such as asthma has significantly increased worldwide, making it a public health concern. There is an urgent need for new anti-inflammatory agents with selective pharmacology and lower toxicity. Plant extracts have been used for centuries in traditional medicine to alleviate inflammatory diseases. In this work, we evaluated the anti-allergic activity of Cymbopogon citratus (Cy), a medicinal herb used by folk medicine to treat asthma. We used a murine model of respiratory allergy to the mite Blomia tropicalis (Bt) and evaluated certain parameters known to be altered in this model. A/J mice were sensitized (100 μg/animal s.c.) and challenged (10 μg/animal i.n.) with Bt mite extract and treated with 60, 120 or 180 mg/kg of Cy standardized hexane extract. The parameters evaluated included: cellular infiltrate in bronchoalveolar lavage (BAL); eosinophil peroxidase activity (EPO); histopathological examination of the lung; serum levels of specific IgE, IgG1 and IgG2a; Th2 cytokine concentrations in BAL and expression of NF-κB. Our results showed that oral administration of a Cy hexane extract (especially 180 mg/Kg) reduced the numbers of leukocytes/eosinophils in BAL; the eosinophil peroxidase activity in BAL; the infiltration of leukocytes in lung tissue; the production of mucus in the respiratory tract; the level of IL-4 in BAL and the nuclear expression of NF-κB. The results presented demonstrate the potential of the Cy hexane extract to modulate allergic asthma; this extract may be an alternative future approach to treat this pathology.

  3. Antimicrobial Effects of Trachyspermum ammi and Cymbopogon ...

    African Journals Online (AJOL)

    Trachyspermum ammi and Cymbopogon citratus essential oils against five common strains of pathogenic fungi was carried out using the agar well diffusion method. The results indicated that l % v/w of T. ammi and C. citratus oils prepared in some bases exhibited remarkable antifungal activity with zone inhibition diameters ...

  4. Antimicrobial Effects of Trachyspermum ammi and Cymbopogon ...

    African Journals Online (AJOL)

    Evaluation of the antimicrobial activity of semisolid formulations of Trachyspermum ammi and Cymbopogon citratus essential oils against five common strains of pathogenic fungi was carried out using the agar well diffusion method. The results indicated that 1 % v/w of T. ammi and C. citratus oils prepared in some bases ...

  5. Atividade fungitóxica in vitro dos óleos essenciais de Lippia sidoides Cham., Cymbopogon citratus(D.C. Stapf. e de seus constituintes majoritários no controle de Rhizoctonia solani e Sclerotium rolfsii

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    A.H. GONÇALVES

    2015-01-01

    Full Text Available RESUMO O objetivo deste estudo foi avaliar o potencial fungitóxicos dos óleos essenciais de Cymbopogon citratus, Lippia sidoides, e de seus constituintes majoritários, sobre o crescimento micelial dos fitopatógenos Rhizoctonia solani e Sclerotium rolfsii. A caracterização química do óleo de L. sidoides demonstrou a presença do carvacrol (33,27% e o 1,8-cineol (24,41% como seus componentes majoritários. Enquanto que o citral (77,6% foi o constituinte majoritário do óleo essencial de C. citratus. A avaliação do potencial fungitóxico dos óleos essenciais e de seus constituintes majoritários foi realizada por meio de ensaios in vitro, avaliando a inibição do crescimento micelial dos microrganismos. Ambos os óleos essenciais inibiram totalmente o crescimento micelial de R. solani na concentração de 400 µg mL-1. O crescimento micelial de S. rolfsii foi inibido pelo óleo essencial de C. citratus na concentração de 300 µg mL-1 e pelo óleo essencial de L. sidoides na concentração de 400 µg mL-1. Em relação aos constituintes majoritários, o 1,8-cineol não apresentou efeito fungitóxico nas concentrações avaliadas. No entanto, o carvacrol e o citral foram mais efetivos que os óleos essenciais havendo ausência de crescimento micelial de R. solani e de S. rolfsii nas concentrações de 200 µg mL-1 e 225 µg mL-1, respectivamente.

  6. Plantes aromatiques du Plateau des Cataractes (Bassin du Congo. Caractérisation du chémotype de l'huile essentielle de Cymbopogon nardus (L. Rendle acclimaté au Congo-Brazzaville

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    Silou, T.

    2017-01-01

    Full Text Available Aromatic plants from the Plateau des Cataractes (Congo Basin. Chemotype characterization of essential oil of Cymbopogon nardus (L. Rendle acclimatized in Congo-Brazzaville. Description. The essential oils of Cymbopogon nardus (L. Rendle, Cymbopogon winterianus Jowitt, Cymbopogon flexuosus (Nees ex Steud. Wats and Cymbopogon citratus L. (DC. Stapf (lemongrass consist of more than 80% of the following constituents: citronellal, geraniol, citral, citronellol, geranyl acetate, and limonene. For the purposes of business transactions, it is therefore important to know the exact chemical composition of the essential oils produced. Objectives. Chemotype evaluation of C. nardus acclimatized on the Plateau des Cataractes. Method. The essential oils of C. nardus were extracted by hydrodistillation and analyzed by chromatography (GC and GC/MS over a period of more than ten years. Results. Cymbopogon nardus was found to produce a Java type citronella essential oil (C. winterianus with the following profile: citronellal (40-48%, geraniol (10-22%, citronellol (10-12%, limonene (2-3%, geranyl acetate (1-2%, linalool (1%. The difference between these two types of citronella, Java and Ceylon, was based on the relative proportions of their three main constituents: citronellal, geraniol and citronellol. Cymbopogon nardus is known for its high variability, with two varieties and sept subvarieties. Conclusions. The citronella established in West and Central Africa under the name of Cymbopogon nardus (Java type could be considered a Cymbopogon winterianus Jowitt, based on the chemical composition of its essential oil.

  7. Avaliação da composição química de Cymbopogon citratus Stapf cultivado em ambientes com diferentes níveis de poluição e a influência na composição do chá = Evaluation of the chemical composition of Cymbopogon citratus Stapf growing in environments with different pollution levels and the influence on tea composition

    Directory of Open Access Journals (Sweden)

    Maria Almerice Lopes da Silva

    2010-01-01

    Full Text Available Cymbopogon citratus Stapf, o popular capim-santo, é espécie originária da Índia, que chegou ao Brasil, possivelmente, no tempo colonial, e era utilizada como planta ornamental, sendo encontrada cultivada em todo o país. Diversos são os usos populares para essa planta, desde tratamento de dores estomacais, intestinais, antidiarreico, até anticelulite e estética de cabelos oleosos. Essa planta se desenvolve em ambientes insalubres como beira de estrada, e isso pode levar a mudanças no seu aspecto químico e, em consequência disso, mudanças em seus derivados. Este trabalho analisou se ocorreu variação da composição química da planta cultivada na presença ou ausência de estresse ambiental (poluição urbana. Foram pesquisados por meio de cromatografia de camada delgada os seguintes compostos: saponinas, iridoides e proantocianidinas, mono e sesquiterpenos, triterpenos e esteroides, luteolina, polifenóis e alcaloides. Concluiu-se que este fator pode ter contribuído para modificação da composição química de suas folhas, reduzindo a síntese de compostos mais polares e favorecendo a síntese de possíveis leucoantocianidinas para provável proteção. Isso poderá acarretar ao chá alterações em sua propriedade farmacológica e toxicológica.Cymbopogon citratus Stapf, popularly known as lemongrass, is an Indian species. It possibly arrived in Brazil during colonial times, where it was used as an ornamental plant, and is found growing throughout the country. There are several popular uses for this plant, including as treatment for stomach pains, diarrhea and cellulite. This plant grows in polluted and unpolluted environments such as roadsides, which can lead to changes in its chemical aspects, and consequently changes in its manufacturing products. This study examined whether there were changes in the chemical composition of plants grown in the presence or absence of environmental stress (urban pollution. The following

  8. Variación de la composición química de los aceites esenciales de cúrcuma (Curcuma longa), hierba luisa (Cymbopogon citratus) y jengibre (Zingiber officinale) en función del tipo de suelo y las variables climáticas de la zona de cultivo de las especies vegetales en las provincias de Santa Elena, Guayas, Los Ríos, Bolívar, Cotopaxi, Tungurahua, Chimborazo, Morona Santiago y Pastaza.

    OpenAIRE

    Altamirano Campaña, Fredy Eduardo; Vásquez Lara, Katherine Jasmín

    2016-01-01

    This research analyze the variation of the chemical composition of essential oils: Turmeric (Curcuma longa), Lemongrass (Cymbopogon citratus) and Ginger (Zingiber officinale) according to soil type and climatic variables in the area of culture plant species in Coast, Sierra and Eastern regions of the central sector of Ecuador; methods of chemical and physical analysis was used to determine the type of soil, pH, conductivity, moisture, organic matter and nutrients (K, Fe, ...

  9. Variación de la composición química de los aceites esenciales de hierba luisa (Cymbopogon citratus) y jengibre (Zingiber officinale) En función de las condiciones ambientales y del tipo de suelo de la zona de cultivo en las provincias de Esmeraldas, Manabí, Santo Domingo, Pichincha, Imbabura, Carchi, Sucumbíos y Napo

    OpenAIRE

    Flores Mejía, Mauricio Fabián; Patiño Pozo, Byron Geovanny

    2016-01-01

    The objective of this research was to analyze the chemical composition (geranialdehyde, neral, caryophyllene, pinene ) of essential oils of species: lemongrass (Cymbopogon citratus) and ginger (Zingiber officinale), in the provinces of Esmeraldas, Manabí, Santo Domingo, Pichincha, Imbabura, Carchi, Sucumbíos and Napo, assessing the influence of environmental factors (temperature, relative humidity, altitude) and soil factors (texture, organic matter, pH, electrical conduct...

  10. ESSENTIAL OILS OF CYMBOPOGON SP. IN THE CONTROL OF FOODBORNE PATHOGENIC BACTERIA

    OpenAIRE

    Brugnera, Danilo Florisvaldo; Oliveira,Maíra Maciel Mattos de; Piccoli,Roberta Hilsdorf

    2011-01-01

    In this study, the agar well diffusion technique was used to determine the antibacterial activity of Cymbopogon nardus (citronella) and Cymbopogon citratus (lemongrass) essential oils, which were applied at different concentrations. The bacterial species used were the foodborne pathogens Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Both essential oils presented antibacterial activity in most concentrations tested. The Minimum Inhibitory Concentra...

  11. Avaliação da composição química de Cymbopogon citratus Stapf cultivado em ambientes com diferentes níveis de poluição e a influência na composição do chá - DOI: 10.4025/actascihealthsci.v32i1.4543 Evaluation of the chemical composition of Cymbopogon citratus Stapf growing in environments with different pollution levels and the influence on tea composition - DOI: 10.4025/actascihealthsci.v32i1.4543

    Directory of Open Access Journals (Sweden)

    Haroudo Sátiro Xavier

    2009-12-01

    Full Text Available Cymbopogon citratus Stapf, o popular capim-santo, é espécie originária da Índia, que chegou ao Brasil, possivelmente, no tempo colonial, e era utilizada como planta ornamental, sendo encontrada cultivada em todo o país. Diversos são os usos populares para essa planta, desde tratamento de dores estomacais, intestinais, antidiarreico, até anticelulite e estética de cabelos oleosos. Essa planta se desenvolve em ambientes insalubres como beira de estrada, e isso pode levar a mudanças no seu aspecto químico e, em consequência disso, mudanças em seus derivados. Este trabalho analisou se ocorreu variação da composição química da planta cultivada na presença ou ausência de estresse ambiental (poluição urbana. Foram pesquisados por meio de cromatografia de camada delgada os seguintes compostos: saponinas, iridoides e proantocianidinas, mono e sesquiterpenos, triterpenos e esteroides, luteolina, polifenóis e alcaloides. Concluiu-se que este fator pode ter contribuído para modificação da composição química de suas folhas, reduzindo a síntese de compostos mais polares e favorecendo a síntese de possíveis leucoantocianidinas para provável proteção. Isso poderá acarretar ao chá alterações em sua propriedade farmacológica e toxicológica.Cymbopogon citratus Stapf, popularly known as lemongrass, is an Indian species. It possibly arrived in Brazil during colonial times, where it was used as an ornamental plant, and is found growing throughout the country. There are several popular uses for this plant, including as treatment for stomach pains, diarrhea and cellulite. This plant grows in polluted and unpolluted environments such as roadsides, which can lead to changes in its chemical aspects, and consequently changes in its manufacturing products. This study examined whether there were changes in the chemical composition of plants grown in the presence or absence of environmental stress (urban pollution. The following

  12. Rendimento, composição química e atividade antilisterial de óleos essenciais de espécies de Cymbopogon Yield, chemical composition and antilisterial activity of essential oils from Cymbopogon species

    Directory of Open Access Journals (Sweden)

    M.M.M Oliveira

    2011-01-01

    Full Text Available Objetivou-se determinar o rendimento, a composição química e avaliar a atividade antilisterial dos óleos essenciais de Cymbopogon citratus (DC. Stapf. (capim-limão e Cymbopogon nardus (L. Rendle (capim-citronela, puros e em combinação. A obtenção dos óleos essenciais foi realizada a partir de folhas frescas, empregando-se a técnica de hidrodestilação e utilizando-se aparelho de Clevenger modificado. Os rendimentos foram calculados a partir da massa obtida na extração e da umidade do material vegetal. A análise qualitativa foi realizada por cromatografia em fase gasosa acoplada à espectrometria de massas e a avaliação dos teores dos constituintes químicos por cromatografia em fase gasosa com detector de ionização de chamas. O efeito bacteriostático de diferentes concentrações dos óleos essenciais, puros e em combinação, foi determinado pela técnica de difusão em ágar. As concentrações mínimas inibitórias (CMIs foram utilizadas na determinação do tempo de ação bactericida. O rendimento, em base seca, foi de 1,39% (v/p para o óleo essencial de C. citratus e de 2,27% (v/p para o óleo essencial de C. nardus. Geranial e neral foram os constituintes majoritários do óleo essencial de C. citratus, enquanto, para C. nardus, foram citronelal, geraniol e citronelol. A maioria das concentrações utilizadas mostrou-se efetiva contra Listeria monocytogenes e observaram-se efeitos bactericidas nas CMIs. Óleos essenciais de C. citratus e C. nardus, puros e em combinação, constituem novas alternativas de antibacterianos naturais a serem utilizados no controle de L. monocytogenes na indústria de alimentos.The aim of this study was to determine the yield and the chemical composition of essential oils from Cymbopogon citratus (DC. Stapf. (lemongrass and Cymbopogon nardus (L. Rendle (citronella, and to evaluate their antilisterial activity when pure and combined. The essential oils were obtained from fresh leaves

  13. Hepatoprotective Effect Of Cymbopogon Citratus Aqueous Extract ...

    African Journals Online (AJOL)

    (2) Received H2O2 (0.5%) with drinking water. (3), and (4) received H2O2 and C. ... Blood samples were collected and serum was used for biochemical assay including liver enzymes activities, total protein, total bilirubin and malonaldehyde, glutathione in serum and liver homogenates. Liver was excised and routinely ...

  14. Influencia de la temperatura y tiempo de secado en la calidad de las hojas de Cymbopogon Citratus D.C. staf

    OpenAIRE

    Otazu Larrasoaña, Iosu; Irisarri Alfonso, Imanol

    2010-01-01

    Las plantas medicinales han sido a lo largo de la historia de la humanidad de suma importancia para el cuidado de la salud y muy utilizadas para la fabricación de medicamentos y remedios naturales. Durante mucho tiempo las plantas medicinales fueron el principal recurso para la medicina. La mayoría de las plantas medicinales son provenientes de países tropicales, de las cuales el 25% de las especies tienen su origen en Brasil. Por eso que en este país varias especies de plantas medicinales so...

  15. Anti-proliferative effect of the essential oil of Cymbopogon citratus (DC) Stapf (lemongrass) on intracellular amastigotes, bloodstream trypomastigotes and culture epimastigotes of Trypanosoma cruzi (Protozoa: Kinetoplastida).

    Science.gov (United States)

    Santoro, G F; Cardoso, M G; Guimarães, L G L; Freire, J M; Soares, M J

    2007-10-01

    This study analyses the anti-proliferative effect of lemongrass essential oil and its main constituent (citral) on all 3 evolutive forms of Trypanosoma cruzi. Steam distillation was used to obtain lemongrass essential oil, with chemical composition determined by gas chromatography (GC) and GC coupled to mass spectrometry (GC-MS). The IC50/24 h (concentration that reduced the parasite population by 50%) of the oil and of citral upon T. cruzi was determined by cell counting in a Neubauer chamber, while morphological alterations were visualized by scanning and transmission electron microscopy. Treatment with the essential oil resulted in epimastigote growth inhibition with IC50=126.5 microg/ml, while the IC50 for trypomastigote lysis was 15.5 microg/ml. The IC50/48 h for the Association Index (% macrophage infection x number of amastigotes per cell) was 5.1 microg/ml, with a strong inhibition of intracellular amastigote proliferation. Ultrastructural analysis demonstrated cytoplasmic and nuclear extraction, while the plasma membrane remained morphologically preserved. Our data show that lemongrass essential oil is effective against T. cruzi trypomastigotes and amastigotes, and that its main component, citral, is responsible for the trypanocidal activity. These results indicate that essential oils can be promising anti-parasitic agents, opening perspectives to the discovery of more effective drugs of vegetal origin for treatment of parasitic diseases. However, additional cytotoxicity experiments on different cell lines and tests in a T. cruzi-mouse model are needed to support these data.

  16. Phytoremediation of metals using lemongrass (Cymbopogon citratus (D.C.) Stapf.) grown under different levels of red mud in soil amended with biowastes.

    Science.gov (United States)

    Gautam, Meenu; Pandey, Divya; Agrawal, Madhoolika

    2017-06-03

    Due to hostile condition of red mud (RM), its utilization for vegetation is restricted. Therefore, RM with biowastes as soil amendment may offer suitable combination to support plant growth with reduced risk of metal toxicity. To evaluate the effects of RM on soil properties, plant growth performance, and metal accumulation in lemongrass, a study was conducted using different RM concentrations (0, 5, 10, and 15% w/w) in soil amended with biowastes [cow dung manure (CD) or sewage-sludge (SS)]. Application of RM in soil with biowastes improved organic matter and nutrient contents and caused reduction in phytoavailable metal contents. Total plant biomass was increased under all treatments, maximally at 5% RM in soil with SS (91.4%) and CD (51.7%) compared to that in control (no RM and biowastes). Lemongrass acted as a potential metal-tolerant plant as its metal tolerance index is >100%. Based on translocation and bioconcentration factors, lemongrass acted as a potential phytostabilizer of Fe, Mn, and Cu in roots and was found efficient in translocation of Al, Zn, Cd, Pb, Cr, As, and Ni from roots to shoot. The study suggests that 5% RM with biowastes preferably SS may be used to enhance phytoremediation potential of lemongrass.

  17. Cymbopogon species; ethnopharmacology, phytochemistry and the pharmacological importance.

    Science.gov (United States)

    Avoseh, Opeyemi; Oyedeji, Opeoluwa; Rungqu, Pamela; Nkeh-Chungag, Benedicta; Oyedeji, Adebola

    2015-04-23

    Cymbopogon genus is a member of the family of Gramineae which are herbs known worldwide for their high essential oil content. They are widely distributed across all continents where they are used for various purposes. The commercial and medicinal uses of the various species of Cymbopogon are well documented. Ethnopharmacology evidence shows that they possess a wide array of properties that justifies their use for pest control, in cosmetics and as anti-inflammation agents. These plants may also hold promise as potent anti-tumor and chemopreventive drugs. The chemo-types from this genus have been used as biomarkers for their identification and classification. Pharmacological applications of Cymbopogon citratus are well exploited, though studies show that other species may also useful pharmaceutically. Hence this literature review intends to discuss these species and explore their potential economic importance.

  18. Cymbopogon Species; Ethnopharmacology, Phytochemistry and the Pharmacological Importance

    Directory of Open Access Journals (Sweden)

    Opeyemi Avoseh

    2015-04-01

    Full Text Available Cymbopogon genus is a member of the family of Gramineae which are herbs known worldwide for their high essential oil content. They are widely distributed across all continents where they are used for various purposes. The commercial and medicinal uses of the various species of Cymbopogon are well documented. Ethnopharmacology evidence shows that they possess a wide array of properties that justifies their use for pest control, in cosmetics and as anti-inflammation agents. These plants may also hold promise as potent anti-tumor and chemopreventive drugs. The chemo-types from this genus have been used as biomarkers for their identification and classification. Pharmacological applications of Cymbopogon citratus are well exploited, though studies show that other species may also useful pharmaceutically. Hence this literature review intends to discuss these species and explore their potential economic importance.

  19. Qualidade de produtos a base de plantas medicinais comercializados no Brasil: castanha-da-índia (Aesculus hippocastanum L., capim-limão (Cymbopogon citratus (DC. Stapf e centela (Centella asiatica (L. Urban Quality of products made from medicinal plants commercialized in Brazil: horsechestnut (Aesculus hippocastanum L., lemongrass (Cymbopogon citratus (DC. Stapf, and gotu kola (Centella asiatica (L. Urban

    Directory of Open Access Journals (Sweden)

    Joabe Gomes de Melo

    2007-03-01

    Full Text Available Com o objetivo de avaliar a qualidade de produtos a base de plantas medicinais, analisou-se dez amostras de castanha-da-índia, onze de capim-limão e seis de centela, comercializadas em farmácias da cidade do Recife, provenientes de indústrias de várias partes do país. Analisamos as informações técnico-científicas nos rótulos e/ou bulas de acordo com as exigências e obrigatoriedades da legislação brasileira (RDC n. 140 de 29/05/2003 e na RDC n. 102 de 30/11/2000, e embasamento da literatura científica. Também avaliou-se as características organolépticas, a autenticidade e a pureza dos produtos. Constatou-se ausência das informações obrigatórias em 92,59% das amostras. Dentre os termos vedados, foi comum a sugestão da inexistência de efeitos colaterais ou adversos. Quanto as indicações terapêuticas não se observou padronização técnica dos termos nem comprovação científica para algumas das atividades atribuídas pelos fabricantes. Todas as amostras foram consideradas autênticas com base nos testes fitoquímicos e farmacobotânicos. Na análise da pureza 59,26% das amostras foram reprovadas, devido principalmente ao elevado teor de umidade e cinzas totais. Constata-se que além dos produtos comercializados carecerem de informações e qualidade adequadas, há necessidade urgente de uma fiscalização efetiva por parte dos órgãos competentes.Aiming to evaluate the quality of products made from medicinal plants, there were analyzed ten samples of horsechestnut, eleven samples of lemongrass, and six samples of gotu kola commercialized in pharmacies from the city of Recife (Pernambuco, Brazil, coming from industries of several parts of the country. We analyzed the technical-scientific information on the labels and/or directions according to the requirements and obligations of Brazilian law (laws "RDC 140 of 29/05/2003" and "RDC 102 of 30/11/2000" and to scientific literature embasement. The products' organoleptic characteristics, authenticity, and purity were also evaluated. The absence of obligatory information was verified in 92.59% of the samples. Among the blacked terms, it was common to find products that suggested inexistent collateral or adverse effects. Technical terms were not standardized and the manufacturers did not provide scientific proof for some of the activities credited to the products. All samples were considered authentic based on the phytochemical and pharmacobotanical tests. The purity analysis considered 59.26% of the samples inappropriate, mainly due to the high total levels of humidity and ashes. It was verified that besides the lack of adequate information and quality of the commercialized products, there is an urgent need for an effective inspection by the suitable agencies.

  20. Influência da luz e da temperatura sobre a oxidação do óleo essencial de capim-limão (Cymbopogon citratus (D.C. Stapf Influence of light and temperature on the oxidation of the essential oil of lemongrass (Cymbopogon Citratus (D.C. Stapf

    Directory of Open Access Journals (Sweden)

    Luiz Gustavo de L. Guimarães

    2008-01-01

    Full Text Available The identification of the chemical compounds of the essential oil was performed with a gas chromatograph coupled to a mass spectrometer. The oil was left in the presence and absence of light and submitted to different temperatures to evaluate its stability. The yields of the major compounds were evaluated every fifteen days. Citral and myrcene, the major compounds of the essential oil, were degraded over time in both the presence and absence of light, but temperature only influenced the degradation of myrcene.

  1. Bioatividade de extratos hidroalcoólicos de Cymbopogon citratus (DC. Stapf. sobre picão-preto (Bidens pilosa L. e alface (Lactuca sativa L. Bioactivity of hydroalcoholic extracts of Cymbopogon citratus (DC. Stapf. on germination and early growth of beggartick (Bidens pilosa L. and lettuce (Lactuca sativa L.

    Directory of Open Access Journals (Sweden)

    L.L. Lousada

    2012-01-01

    Full Text Available Este trabalho visou avaliar a bioatividade de extratos hidroalcoólicos de capim-limão sobre germinação e crescimento inicial da planta daninha picão-preto (Bidens pilosa L. e da planta teste alface (Lactuca sativa L.. A partir de maceração hidroalcoólica de folhas secas e rasuradas (127,46 g de capim-limão em 1L de álcool de cereais (70%, foram preparados os tratamentos como extratos hidroalcoólicos (HA pela diluição (v/v do macerado filtrado em água deionizada na proporção 1:1 (HA1:1 e 1:2 (HA1:2; dos quais foram obtidos os respectivos extratos secos (ES, a partir da evaporação da fase líquida de duas alíquotas de 50 mL de cada extrato HA, que após re-suspendidas em igual volume de água, sendo uma autoclavada (1 atm por 15 minutos, resultando nos extratos secos de HA1:1 e HA1:2 autoclavados (ES1:1A e ES1:2A e nos extratos secos não autoclavados (ES1:1 e ES1:2; e água (AG como controle. No primeiro dia dos bioensaios, foram aplicados 2 mL dos tratamentos, em DIC, com cinco repetições. Avaliou-se a porcentagem de germinação (G%, Índice de Velocidade de Germinação (IVG, altura da parte aérea (AA e comprimento de radícula (CR de aquênios (25 de picão-preto e de alface distribuídos em placas de Petri e mantidos em câmara de germinação (B.O.D. por duas semanas. Os extratos HA1:1 e HA1:2 inibiram a G%, AA e CR das duas espécies. Todos os extratos secos reduziram a G%, IVG e o CR da alface. Para o picão preto, apenas o extrato ES1:1 reduziu a G% e o IVG foi reduzido por todos os extratos, a exceção do ES1:1A, mas nenhum extrato influenciou o crescimento inicial desta espécie.This study aimed to evaluate the bioactivity of hydroalcoholic extract of lemongrass on the germination and early growth of the weed plant beggartick (Bidens pilosa L. and the test plant lettuce (Lactuca sativa L.. From the hydroalcoholic maceration of dried and cut leaves of lemon grass (127.46 g in 1 L grain alcohol (70%, the following treatments were prepared, hydro-alcoholic (HA extracts by diluting (v/v the macerate in deionized water at 1:1 (HA1:1 and 1:2 (HA1:2 proportions, obtaining the respective dried extracts (DE from the evaporation of the liquid phase of two 50-mL aliquots of each HA extract; after resuspension in the same water volume, one aliquot was autoclaved (1 atm for 15 minutes resulting in HA1:1 and HA1:2 dried autoclaved extracts (DE1:1A and DE1:2A and in dried non-autoclaved extracts (ES1:1 and ES1:2, and water as control. On the first day of bioassays, 2mL of treatments were applied, in completely randomized design, with 5 replicates. Germination percentage (G%, Germination Speed Index (GSI, shoot height (SH and radicle length (RL of achenes (25 of beggartick and lettuce were evaluated after having been distributed in Petri dishes and kept in a germination chamber (B.O.D. for two weeks. HA1:1 and HA1:2 extracts inhibited G%, SH and RL of both species. All dried extracts reduced G%, GSI and CR of lettuce. For beggartick, only ES1:1 extract reduced G% while GSI was reduced in all extracts, except ES1:1A, but no extract influenced the early growth of this species.

  2. ANÁLISE DA COMPOSIÇÃO QUÍMICA DO ÓLEO ESSENCIAL DE CAPIM SANTO (Cymbopogon citratus OBTIDO ATRAVÉS DE EXTRATOR POR ARRASTE COM VAPOR D´ÁGUA CONSTRUÍDO COM MATERIAS DE FÁCIL AQUISIÇÃO E BAIXO CUSTO

    Directory of Open Access Journals (Sweden)

    Felipe Maia Silva

    2014-08-01

    Full Text Available Os óleos essenciais são substâncias naturais de grande importância econômica, sendo utilizados em perfumaria, cosméticos, alimentos e medicamentos. São obtidos por diferentes métodos de extração e encontrados em diferentes partes de plantas aromáticas. Contudo, a aquisição de equipamentos para extração de óleos essenciais representa um custo significativo para as instituições de ensino e pesquisa do país, principalmente nos últimos anos em que tem ocorrido redução de investimentos nas áreas de Ciência e Tecnologia. Desta forma, esse trabalho teve como objetivo a construção de um extrator de óleo essencial utilizando materiais de fácil acesso e mão de obra local. O extrator construído possui as dimensões de 60 cm de altura e 30 cm de diâmetro. Seu aquecimento é realizado por resistência elétrica com temperatura controlada por termostato (faixa de 0 a 120°C e possui uma campânula metálica vedada por selo d’água que está acoplada a um sistema de condensação. O experimento teste foi realizado fazendo extração de 612 g de capim santo (Cymbopogon citratus. Após análise obteve-se um rendimento de 0,48% de óleo essencial na extração. Portanto, este trabalho demonstra a busca no desenvolvimento de tecnologias inovadoras, fazendo uso de materiais facilmente encontrados no mercado e utilizando mão de obra local, contribuindo, não só para o acúmulo de conhecimento acadêmico, mas, acima de tudo, com a capacitação de recursos humanos, geração de renda local e com a transferência de novas tecnologias que possam servir de base para a elaboração de novos produtos, neste caso, os óleos essenciais.

  3. ESSENTIAL OILS OF CYMBOPOGON SP. IN THE CONTROL OF FOODBORNE PATHOGENIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Danilo Florisvaldo BRUGNERA

    2011-08-01

    Full Text Available In this study, the agar well diffusion technique was used to determine the antibacterial activity of Cymbopogon nardus (citronella and Cymbopogon citratus (lemongrass essential oils, which were applied at different concentrations. The bacterial species used were the foodborne pathogens Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Both essential oils presented antibacterial activity in most concentrations tested. The Minimum Inhibitory Concentrations (MICs founded were: 7.81μL/mL (S. aureus and 3.90μL/mL (E. coli and P. aeruginosa, for C. nardus essential oil; and 3.90μL/mL (S. aureus, E. coli and P. aeruginosa, for C. citratus essential oil. The essential oils used were shown as promising natural antibacterials for pathogenic bacteria control in the food industry.

  4. Lemon grass ( Cymbopogon citratus ) essential oil as a potent anti ...

    African Journals Online (AJOL)

    Aims: In the present study, lemon grass essential oil (LGEO) was evaluated for its in vivo topical and oral antiinflammatory effects, and for its in vitro antifungal activity using both liquid and vapor phases. Methods:The chemical profile ofLGEOas determined bygas chromatography-mass spectrometry analysis revealed ...

  5. Hepatoprotective and antioxidant effects of Cymbopogon citratus Stapf

    African Journals Online (AJOL)

    the animal with CS extract reduced the levels of hepatic markers (AST and ALT). Pre-treatment with CS ... Tropical Journal of Pharmaceutical Research is indexed by Science Citation Index (SciSearch), Scopus,. International Pharmaceutical Abstract .... testing the first dose with one animal, we found that the animal survived.

  6. Influence of metals on essential oil content and composition of lemongrass (Cymbopogon citratus (D.C.) Stapf.) grown under different levels of red mud in sewage sludge amended soil.

    Science.gov (United States)

    Gautam, Meenu; Agrawal, Madhoolika

    2017-05-01

    Lemongrass is a commercially important perennial herb with medicinal value and ability to tolerate high alkaline and saline conditions. Essential oil bearing plants can grow safely in soil contaminated with heavy metals without severe effects on morphology and oil yield. The present study was aimed to assess the essential oil content and composition in lemongrass in response to elevated metals in above-ground plant parts. Pot experiment was conducted for six months using sewage sludge as soil amendment (soil: sludge: 2:1 w/w) followed by red mud treatments (0, 5, 10 and 15% w/w). Garden soil without sludge and red mud was control and there were ten replicates of each treatment. Oil content in leaves was differently affected due to presence of metals in soil under different treatments. Oil content under SRM5 (5% red mud) treatment was raised by 42.9 and 11.5% compared to the control and SRM0 treatment, respectively. Among identified compounds in oil under red mud treatments, 17 compounds contributed more than 90% of total volatiles (citral contributing approximately 70%). Under SRM10 treatment, essential oil showed maximum citral content (75.3%). Contents of Fe, Zn, Cu, Cd, Ni and Pb in above-ground plant parts exceeded, whereas Mn was detected within WHO permissible limits for medicinal plants. However, metal contents in essential oil were well within FSSAI limits for food. The study suggests utilization of 5 and 10% red mud in sludge amended soil for lemongrass cultivation to have better oil yield and quality, without metal contamination. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Chemical composition, cytotoxicity and in vitro antitrypanosomal and antiplasmodial activity of the essential oils of four Cymbopogon species from Benin.

    Science.gov (United States)

    Kpoviessi, Salomé; Bero, Joanne; Agbani, Pierre; Gbaguidi, Fernand; Kpadonou-Kpoviessi, Bénédicta; Sinsin, Brice; Accrombessi, Georges; Frédérich, Michel; Moudachirou, Mansourou; Quetin-Leclercq, Joëlle

    2014-01-01

    Cymbopogon species are largely used in folk medicine for the treatment of many diseases some of which related to parasitical diseases as fevers and headaches. As part of our research on antiparasitic essential oils from Beninese plants, we decided to evaluate the in vitro antiplasmodial and antitrypanosomal activities of essential oils of four Cymbopogon species used in traditional medicine as well as their cytotoxicity. The essential oils of four Cymbopogon species Cymbopogon citratus (I), Cymbopogon giganteus (II), Cymbopogon nardus (III) and Cymbopogon schoenantus (IV) from Benin obtained by hydrodistillation were analysed by GC/MS and GC/FID and were tested in vitro against Trypanosoma brucei brucei and Plasmodium falciparum respectively for antitrypanosomal and antiplasmodial activities. Cytotoxicity was evaluated in vitro against Chinese Hamster Ovary (CHO) cells and the human non cancer fibroblast cell line (WI38) through MTT assay to evaluate the selectivity. All tested oils showed a strong antitrypanosomal activity with a good selectivity. Sample II was the most active against Trypanosoma brucei brucei and could be considered as a good candidate. It was less active against Plasmodium falciparum. Samples II, III and IV had low or no cytotoxicity, but the essential oil of Cymbopogon citratus (I), was toxic against CHO cells and moderately toxic against WI38 cells and needs further toxicological studies. Sample I (29 compounds) was characterised by the presence as main constituents of geranial, neral, β-pinene and cis-geraniol; sample II (53 compounds) by trans-p-mentha-1(7),8-dien-2-ol, trans-carveol, trans-p-mentha-2,8-dienol, cis-p-mentha-2,8-dienol, cis-p-mentha-1(7),8-dien-2-ol, limonene, cis-carveol and cis-carvone; sample III (28 compounds) by β-citronellal, nerol, β-citronellol, elemol and limonene and sample IV (41 compounds) by piperitone, (+)-2-carene, limonene, elemol and β-eudesmol. Our study shows that essential oils of Cymbopogon genus can

  8. Primeira ocorrência de ferrugem em capim-limão causada por Puccinia cymbopogonis no Brasil First report of the lemongrass rust fungi caused by Puccinia cymbopogonis in Brazil

    Directory of Open Access Journals (Sweden)

    João Batista Vida

    2006-03-01

    Full Text Available È registrada a primeira ocorrência de ferrugem em capim-limão (Cymbopogon citratus (DC. Stapf, causada por Puccinia cymbopogonis Mass., no Brasil, Estado do Paraná.It is reported the first occurrence of the lemongrass (Cymbopogon citratus (DC. Stapf rust fungi caused by Puccinia cymbopogonis Mass. in Brazil, State of Paraná.

  9. Kajian Aktivitas Antibakteri Minyak Daun Sereh (Cymbopogon citratus pada Adonan Sate Lilit Ikan Laut

    Directory of Open Access Journals (Sweden)

    DewaNyoman Adi Paramartha

    2015-03-01

    Full Text Available Lemongrass is one of the spceies often used in cooking or as traditional medicine.The importance components in lemongrass oil that act as antimicrobial is citral. In this research lemongrass oil isolated by steam distilation method and lemongrass oil were tested against Escherichia coli, Staphylococcus aureus, and Salmonella typhi using the agar diffusion method. Antibacterial activity also evaluated on traditional fish satay dough, and tested its organoleptic value. The result showed that lemongrass oil significantly inhibited E. coli with minimum inhibiting concentration (MIC 0.72 µl/ml and minimum bactericidal concentration (MBC 2.89 µl/ml, S. typhi with MIC 0.65 µl/ml and MBC 2.59 µl/ml, S. aureus with MIC 0.64 µl/ml and MBC 2.57 µl/ml. Antibacterial activity studies of lemongrass oil as potential food aditive was evaluated by adding highest MIC and MBC value (0.72 and 2.89 µl/g on traditional fish satay dough. The result showed that adding lemongrass oil 0.72µl/g is not significantly inhibit nature growing bacteria E. coli, Salmonella, and Staphylococcus on satay dough, but adding 2.89 µl/g lemongras oil only can signigicantly inhibit E. coli, Salmnoella, and Staphylococcus at 0 hours of incubation period, but cannot inhibit it’s log phase up to 24 hours of incubation. Organoleptic of added lemongrass oil on fish satay douh was showed that adding 0.72 µl/g of lemongrass oil was not significant on taste and smell, but adding 2.89 µl/g was significant on taste and smell compared to control.

  10. Etude de l'activité antifongique d'extraits de Cymbopogon citratus ...

    African Journals Online (AJOL)

    3UFR SVT/Protection et amélioration des plantes, Université de Ouagadougou, Burkina Faso. *Corresponding author; E-Mail: tiendreassita2@yahoo.fr. RESUME. La culture du riz est sujette à de nombreuses contraintes comme les agents fongiques qui sont capables d'engendrer une réduction importante du rendement.

  11. Antibacterial activity of lemongrass(Cymbopogon citratus) oil against some selected pathogenic bacterias

    National Research Council Canada - National Science Library

    Mohd Irfan Naik Bashir Ahmad Fomda Ebenezar Jaykumar Javid Ahmad Bhat

    2010-01-01

    ... organisms.Methods:Lemongrass oil was investigated for activity against Staphylococcus aureus (S.aureus),Bacillus cereus(B.cereus),Bacillus subtilis(B.subtilis),Escherichia coli(E.coli), Klebsiella pneumoniae...

  12. Efficacité des huiles essentielles de Cymbopogon citratus et de ...

    African Journals Online (AJOL)

    faible toxicité comparée à celle des additifs alimentaires synthétiques (Bassolé et al.,. 2001). De même, les restrictions imposées par les organismes internationaux quant à l'utilisation des conservateurs de synthèse chimique à cause des risques sanitaires et environnementaux (Yèhouénou et al., 2010) suscitent de plus en ...

  13. Karakterisasi Kemasan Kertas Aktif dengan Penambahan Oleoresin Ampas Destilasi Sereh Dapur (Cymbopogon citratus

    Directory of Open Access Journals (Sweden)

    Lia Umi Khasanah

    2017-03-01

    Full Text Available The aims of this research were to determine the effect of lemongrass distillation dregs oleoresin concentration (0 %, 2 %, 4 %, and 6 % b/b on the active paper packaging characteristics (sensory, water content, thickness, tensile strength, fold endurance and antimicrobial activity, to determine the functional groups of the control and selected active paper packaging, to determine the effect of days of storage (0, 5, 10, 15, and 20 day on the control and selected active paper packaging characteristics (tensile strength, and fold endurance, and to determine antimicrobial activity of the control and selected active paper packaging during 20 days storage. The result showed that the concentration of lemongrass distillation dregs oleoresin significantly affected the color, overall, tensile strength, fold endurance, and antimicrobial activity while did not significantly affected the flavor, texture, water content, and thickness of the active paper packaging. The addition of lemongrass distillation dregs oleoresin increased the water content, thickness, microbial activity, while decreased the panelists preference, tensile strength and fold endurance of the active paper packaging. The spectrum of functional groups of the active paper packaging showed the presence of chitosan, cellulose, tween 80, and lemongrass oleoresin. The storage days had no significant effect on tensile strength and fold endurance of the control and selected active paper packaging. The control and selected active paper packaging were significantly different at each 5 days storage. However the 20 day of storage showed no significant effect on the antimicrobial activity of the control and selected active paper packaging.   ABSTRAK Tujuan dari penelitian ini adalah untuk mengetahui pengaruh konsentrasi oleoresin ampas destilasi sereh dapur (0 %, 2 %, 4 %, dan 6 % b/b terhadap karakteristik kemasan kertas aktif (analisis sensoris, kadar air, ketebalan, ketahanan tarik, ketahanan lipat, dan aktifitas antimikroba, mengetahui gugus fungsi kemasan kertas aktif kontrol dan konsentrasi oleoresin ampas destilasi sereh dapur terpilih, mengetahui pengaruh waktu penyimpanan (0, 5, 10, 15, dan 20 hari terhadap karakteristik kemasan kertas aktif kontrol dan konsentrasi oleoresin ampas destilasi sereh dapur terpilih (uji ketahanan lipat dan ketahanan tarik, dan mengetahui aktivitas antimikroba kemasan kertas aktif kontrol dan konsentrasi oleoresin ampas destilasi sereh dapur terpilih sebelum dan setelah penyimpanan selama 20 hari. Hasil penelitian menunjukkan bahwa konsentrasi oleoresin berpengaruh nyata terhadap warna, overall (penerimaan keseluruhan, ketahanan tarik, ketahanan lipat, dan aktivitas antimikroba tetapi berpengaruh tidak nyata terhadap aroma, tekstur, kadar air, dan ketebalan kemasan kertas aktif. Penambahan oleoresin ampas destilasi sereh dapur meningkatkan kadar air, ketebalan, dan aktivitas antimikroba serta menurunkan ketahanan tarik, ketahanan lipat, dan penerimaan panelis. Kemasan kertas aktif mengandung gugus fungsi selulosa, kitosan, dan tween 80 serta pada kemasan kertas aktif penambahan oleoresin konsentrasi 2 % terdapat gugus fungsi oleoresin sereh dapur. Waktu penyimpanan tidak berpengaruh secara nyata terhadap ketahanan tarik dan ketahanan lipat kemasan kertas aktif kontrol dan konsentrasi terpilih. Kemasan kertas aktif kontrol dengan kemasan kertas aktif penambahan oleoresin konsentrasi 2 % berbeda nyata di setiap 5 hari penyimpanan. Namun, penyimpanan selama 20 hari tidak berpengaruh secara nyata terhadap aktivitas antimikroba kemasan kertas aktif kontrol dan konsentrasi terpilih.

  14. Lemon grass (Cymbopogon citratus) ameliorates murine spontaneous ileitis by decreasing lymphocyte recruitment to the inflamed intestine.

    Science.gov (United States)

    Watanabe, Chikako; Hokari, Ryota; Komoto, Shunsuke; Kurihara, Chie; Okada, Yoshikiyo; Matsunaga, Hisayuki; Takebayashi, Koichi; Kawaguchi, Atsushi; Nagao, Shigeaki; Tsuzuki, Yoshikazu; Yokoyama, Hirokazu; Hibi, Toshifumi; Miura, Soichiro

    2010-07-01

    Aberrant leukocyte migration has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Lemon grass is a natural herb that contains citral, which suppresses lymphocyte expression of gut homing molecules by inhibiting retinoic acid formation. We therefore hypothesized that lemon grass intake could ameliorate excess migration of leukocytes to the inflamed intestine in chronic ileitis. Migration of fluorescence-labeled T cells to microvessels in the ileal mucosa of SAMP1/Yit mice was monitored using intravital microscopy. In some mice, lemon grass solution was administered for two weeks. For evaluation of the effects on chronic ileitis, mice were treated with lemon grass for 26 weeks. Surface expression of beta7 and CCR9 on T lymphocytes was stronger in SAMP1/Yit mice than in AKR/J mice. Lemon grass treatment attenuated the surface expression of beta7-integrin and CCR9. The number of adherent lymphocytes to microvessels in chronic inflamed ileum was significantly few when lymphocytes were isolated from lemon grass treated mice. Long-term lemon grass treatment improved ileitis in SAMP1/Yit mice, which was assessed by body weight, histological changes and the infiltration of beta7-positive cells. Lemon grass ameliorated ileitis through decreasing lymphocyte migration by inhibiting beta7-expression, suggesting its therapeutic usefulness for IBD.

  15. Antimicrobial property of lemongrass (Cymbopogon citratus) oil against pathogenic bacteria isolated from pet turtles.

    Science.gov (United States)

    De Silva, B C J; Jung, Won-Gi; Hossain, Sabrina; Wimalasena, S H M P; Pathirana, H N K S; Heo, Gang-Joon

    2017-06-01

    The usage of essential oils as antimicrobial agents is gaining attention. Besides, pet turtles were known to harbor a range of pathogenic bacteria while the turtle keeping is a growing trend worldwide.The current study examined the antimicrobial activity of lemon grass oil (LGO) against seven species of Gram negative bacteria namely; Aeromonas hydrophila, A. caviae, Citrobacter freundii, Salmonella enterica, Edwardsiella tarda, Pseudomonas aeruginosa, and Proteus mirabilis isolated from three popular species of pet turtles. Along with the results of disc diffusion, minimum inhibitory and minimum bactericidal concentration (MIC and MBC) tests, LGO was detected as effective against 6 species of bacteria excluding P. aeruginosa. MIC of LGO for the strains except P. aeruginosa ranged from 0.016 to 0.5% (V/V). The lowest MIC recorded in the E. tarda strain followed by A. hydrophilla, C. freundii, P. mirabilis, and S. enterica. Interestingly, all the bacterial species except E. tarda were showing high multiple antimicrobial resistance (MAR) index values ranging from 0.36 to 0.91 upon the 11 antibiotics tested although they were sensitive to LGO.

  16. Essential oil production of lemongrass (Cymbopogon citratus under organic compost containing sewage sludge

    Directory of Open Access Journals (Sweden)

    Júlia V. d'Ávila

    Full Text Available ABSTRACT One of the main urban polluting agents are the sewers, which even with proper treatment end up generating a polluting waste, the sewage sludge. One of the options for the disposal of this sludge is the use in agriculture, due to its high content of organic matter and nutrients. This study aimed to use urban sewage sludge for lemongrass cultivation and essential oil production. The plants were grown in soil containing different organic compost doses (0, 5, 10, 20, 40 and 60 t ha-1, formed from the sewage sludge composting process and waste of urban vegetation pruning. At harvest, plants were analyzed for the concentration of nutrients, chlorophyll content, number of tillers, biomass production, essential oil content and the microbiological quality of the leaves. The results showed that the addition of the compost increased the levels of nutrients in the plants, mainly nitrogen, positively influencing the production of tillers, biomass, chlorophyll contents, yield and essential oil content.

  17. Determinação da qualidade microbiológica e físico-química de chás de Cymbopogon citratus (D.C Stapf (capim-limão = Evaluation of the microbiological and physical-chemical qualities of lemongrass tea

    Directory of Open Access Journals (Sweden)

    Eliane Carneiro Gomes

    2008-01-01

    Full Text Available Em função do grande volume de produção e comercialização do capim-limão, estima-se que uma contaminação microbiológica deste produto possa representar importante risco para a saúde pública. Esta pesquisa visou avaliar marcas de chá de capimlimão, em relação às qualidades microbiológica e físico-química, tendo como base alegislação brasileira do Ministério da Saúde. Nenhuma das amostras apresentou Salmonella sp., porém em 50% delas, houve presença de coliformes a 35ºC. Em três amostras, evidenciaram-se coliformes a 45ºC, com presença de Escherichia coli em uma destas. 81,25%das amostras apresentaram bolores e leveduras, porém sem relação direta com os teores de umidade observados. Dentre os fungos presentes, identificou-se Aspergillus niger, no entanto sem produção de aflatoxinas. Todos infusos analisados negativaram a contaminação evidenciada nos testes com o produto seco. Os resultados indicaram possíveis falhas nos procedimentos pós-colheita e de comercialização. A implementação do Sistema APPCC (HACCP poderia substancialmente minimizar esta contaminação.Considering the great volume of lemongrass production andcommercialization, it is estimated that a potential microbiological contamination of this product could represent an important hazard to public health. This study was performed to evaluate different brands of lemongrass tea, regarding their microbiological and physicalchemical quality, based on the legislation of the Brazilian Health Ministry. No traces of Salmonella sp. were found, but in 50% of samples, the presence of coliforms was detected at 35ºC. Three samples presented coliforms at 45ºC, with Escherichia coli found in one of them. 81.25% of samples presented molds and yeasts. Among the fungi present, Aspergillus niger was identified, but aflatoxins were absent. None of the infusions analyzed presented the contamination evidenced in the dry product. The results obtained may be indicative of failure in procedures of postharvest and commercialization. The implementation of a hazard analysis and critical control point system (HACCP could reduce this contamination substantially.

  18. Short Communication: Association of Cymbopogon plurinodis with ...

    African Journals Online (AJOL)

    In a camp, typical of the Sourish Mixed Bushveld, a marked decrease in the abundance of Cymbopogon plurinodis along a soil gradient from high to low clay content was found. The association appears to be independent of the grazing treatment over a 51-year period as the population size of C. plurinodis has remained ...

  19. Actividad antimicrobiana de extractos hidroetanólicos de limoncillo (Cymbopogon citratus y cúrcuma (Curcuma longa

    Directory of Open Access Journals (Sweden)

    Ana Silvia Falco

    2011-06-01

    Full Text Available Los extractos de plantas se han convertido en potenciales alternativas tanto para la industria de medicamentos como para la alimentaria debido a la actividad antioxidante de los compuestos naturales y al desarrollo de multirresistencia por parte de los microorganismos a los conservantes y antibióticos de uso común. El objetivo del presente trabajo consistió en evaluar la capacidad antimicrobiana de los extractos hidroalcohólicos de limoncillo y cúrcuma frente a Escherichia coli, Staphylococcus aureus, Saccharomyces sake y Aspergillus oryzae. El extracto de cúrcuma presentó elevada actividad bactericida y antifúngica a concentraciones de 3,11 y 5,65 mg ácido gálico/mL extracto.

  20. Changes in essential oil during enzyme-assisted ensiling of lemongrass (Cymbopogon citratus Stapf.) and lemon eucalyptus (Eucalyptus citriodora Hook).

    Science.gov (United States)

    Dudai, N; Weinberg, Z G; Larkov, O; Ravid, U; Ashbell, G; Putievsky, E

    2001-05-01

    Changes in essential oil during ensiling of lemongrass and lemon eucalyptus were studied. Wilted lemongrass and eucalyptus leaves were ensiled in 0.25-L anaerobic jars. Samples consisted of a control (no additives) and a treated sample (0.5% glucose and lactic acid bacteria and 1% cellulase plus 1% hemicellulase plus pectinase). Three jars per treatment were sampled on days 2, 6, 10, and 36 for analysis of essential oil. Essential oil was obtained by extraction and by hydrodistillation. Extraction efficacy of essential oil from the lemongrass was improved by the enzyme treatment, but it was much lower than the amount obtained by distillation. The major components of the essential oil were neral and geranial. In the eucalyptus, total essential oils obtained by distillation decreased during ensiling, and the amount was similar to the amount obtained by extraction. Citronellal, which was the major component of the essential oil in the fresh eucalyptus leaves, decreased, whereas isopulegol and 3,8-terpinolhydrate increased during ensiling.

  1. Actividad antimicrobiana de extractos hidroetanólicos de limoncillo (Cymbopogon citratus) y cúrcuma (Curcuma longa)

    OpenAIRE

    Ana Silvia Falco; Walter José Martínez; José Luis Rodríguez; Margarita Núñez de Villavicencio; Eva Sevillano

    2011-01-01

    Los extractos de plantas se han convertido en potenciales alternativas tanto para la industria de medicamentos como para la alimentaria debido a la actividad antioxidante de los compuestos naturales y al desarrollo de multirresistencia por parte de los microorganismos a los conservantes y antibióticos de uso común. El objetivo del presente trabajo consistió en evaluar la capacidad antimicrobiana de los extractos hidroalcohólicos de limoncillo y cúrcuma frente a Escherichia coli, Staphylococcu...

  2. Actividad antimicrobiana de extractos hidroetanólicos de limoncillo (Cymbopogon citratus y cúrcuma (Curcuma longa

    Directory of Open Access Journals (Sweden)

    Ana Silvia Falco

    2011-01-01

    Full Text Available Los extractos de plantas se han convertido en potenciales alternativas tanto para la industria de medicamentos como para la alimentaria debido a la actividad antioxidante de los compuestos naturales y al desarrollo de multirresistencia por parte de los microorganismos a los conservantes y antibióticos de uso común. El objetivo del presente trabajo consistió en evaluar la capacidad antimicrobiana de los extractos hidroalcohólicos de limoncillo y cúrcuma frente a Escherichia coli, Staphylococcus aureus, Saccharomyces sake y Aspergillus oryzae. El extracto de cúrcuma presentó elevada actividad bactericida y antifúngica a concentraciones de 3,11 y 5,65 mg ácido gálico/mL extracto.

  3. Efficacy of Aqueous Extract of Lemon Grass ( Andropogon citratus L ...

    African Journals Online (AJOL)

    An experiment to determine the effects of lemon grass, Andropogon citratus L. extract on the rootknot nematodes (Meloidogyne spp.) of okra was conducted. Phytochemical analyses of the bioactive ingredients in lemon grass were carried out to determine the chemical compounds with nematicidal activities present in lemon ...

  4. Development of simple sequence repeat markers in cymbopogon species.

    Science.gov (United States)

    Kumar, Jitendra; Verma, Vijeshwar; Shahi, Ashok Kumar; Qazi, Gulam Nab; Balyan, Harindra Singh

    2007-03-01

    The genus Cymbopogon comprises about 140 species, which produce characteristic aromatic essential oils. However, the phenotypic identification of species of Cymbopogon has been difficult as a result of widespread occurrence of natural variants, which differ in ploidy levels and chemotaxonomic complexities. Therefore, we have developed a set of simple sequence repeat markers from a genomic library of Cymbopogon jwarancusa to help in the precise identification of the species (including accessions) of Cymbopogon. For this purpose, we isolated 16 simple sequence repeat containing genomic deoxyribonucleic acid clones of C. jwarancusa, which contained a total of 32 simple sequence repeats with a range of 1 to 3 simple sequence repeats per clone. The majority (68.8%) of the 32 simple sequence repeats comprised dinucleotide repeat motifs followed by simple sequence repeats with trinucleotide (21.8%) and other higher order repeat motifs. Eighteen (81.8%) of the 22 designed primers for the above simple sequence repeats amplified products of expected sizes, when tried with genomic DNA of C. jwarancusa, the source species. Thirteen (72.2%) of the 18 functional primers detected polymorphism among the three species of Cymbopogon (C. flexuosus, C. pendulus and C. jwarancusa) and amplified a total of 95 alleles (range 1-18 alleles) with a PIC value of 0.44 to 0.96 per simple sequence repeat. Thus, the higher allelic range and high level of polymorphism demonstrated by the newly developed simple sequence repeat markers are likely to have many applications such as in improvement of essential oil quality by authentication of Cymbopogon species and varieties and mapping or tagging the genes controlling agronomically important traits of essential oils, which can further be utilized in marker assisted breeding.

  5. Determinação da qualidade microbiológica e físico-química de chás de Cymbopogon citratus (D.C Stapf (capim-limão - DOI: 10.4025/actascihealthsci.v30i1.4396 Evaluation of the microbiological and physical-chemical qualities of lemongrass tea - DOI: 10.4025/actascihealthsci.v30i1.4396

    Directory of Open Access Journals (Sweden)

    Raquel Rejane Bonato Negrelle

    2008-07-01

    Full Text Available Em função do grande volume de produção e comercialização do capim-limão, estima-se que uma contaminação microbiológica deste produto possa representar importante risco para a saúde pública. Esta pesquisa visou avaliar marcas de chá de capim-limão, em relação às qualidades microbiológica e físico-química, tendo como base a legislação brasileira do Ministério da Saúde. Nenhuma das amostras apresentou Salmonella sp, porém em 50% delas, houve presença de coliformes a 35ºC. Em três amostras, evidenciaram-se coliformes a 45ºC, com presença de Escherichia coli em uma destas. 81,25% das amostras apresentaram bolores e leveduras, porém sem relação direta com os teores de umidade observados. Dentre os fungos presentes, identificou-se Aspergillus niger, no entanto sem produção de aflatoxinas. Todos infusos analisados negativaram a contaminação evidenciada nos testes com o produto seco. Os resultados indicaram possíveis falhas nos procedimentos pós-colheita e de comercialização. A implementação do Sistema APPCC (HACCP poderia substancialmente minimizar esta contaminação.Considering the great volume of lemongrass production and commercialization, it is estimated that a potential microbiological contamination of this product could represent an important hazard to public health. This study was performed to evaluate different brands of lemongrass tea, regarding their microbiological and physical-chemical quality, based on the legislation of the Brazilian Health Ministry. No traces of Salmonella sp were found, but in 50% of samples, the presence of coliforms was detected at 35ºC. Three samples presented coliforms at 45ºC, with Escherichia coli found in one of them. 81.25% of samples presented molds and yeasts. Among the fungi present, Aspergillus niger was identified, but aflatoxins were absent. None of the infusions analyzed presented the contamination evidenced in the dry product. The results obtained may be indicative of failure in procedures of postharvest and commercialization. The implementation of a hazard analysis and critical control point system (HACCP could reduce this contamination substantially.

  6. Development of lignin in Themeda triandra, Cymbopogon plurinodis ...

    African Journals Online (AJOL)

    The amount and distribution of lignin in three grass species was determined. Two climax species, Themeda triandra and Cymbopogon plurinodis and one pioneer species, Eragrostis lehmanniana were used in the investigation. Leaf samples of the three grass species were taken at four stages of growth and samples of the ...

  7. Habitat factors influencing the distribution of Cymbopogon validus in ...

    African Journals Online (AJOL)

    The factors influencing the distribution of Cymbopogon validus in Mkambati Game Reserve were investigated using multivariate techniques. C. validus was found to be present on nutrient-rich, clay soils and absent from dystrophic, sandy soils. This could account for the patchy distribution of C. validus in the reserve and may ...

  8. Ethanol and high-value terpene co-production from lignocellulosic biomass of Cymbopogon flexuosus and Cymbopogon martinii

    Science.gov (United States)

    Cymbopogon flexuosus and C. martinii are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosi...

  9. PEMANFAATAN SEREH (Cymbopogon Cytratus DALAM MENURUNKAN BAU PADA PUPUK ORGANIK CAIR DAN POTENSINYA DALAM MENINGKATKAN PRODUKSI TANAMAN CABAI (Capsicum Annum

    Directory of Open Access Journals (Sweden)

    Nurhasanah Nurhasanah

    2013-09-01

    Full Text Available Research in the use of lemongrass (Cymbopogon citratus to reduce odors in liquid organic fertilizer has been conducted in Bogor for 6 months. This study begin with a liquid organic fertilizer produced from 1 kg of shrimp waste, 1 kg of maize, 1 kg of bean sprouts, 10 liters of coconut water, 500 ml of EM4 and 500 g of sugar through fermentation process for 6 weeks. Then the result of liquid organic fertilizer was added by an ingredient lemongrass as deodorizing with doses of 0, 10%, 20% and 30% (w/v. After that it is fermented for 2 weeks. The next stage was the application of liquid organic fertilizer as a foliar fertilizer at chillies (Capsicum annum planting using a completely randomized design (CRD 1 factors type of using liquid organic fertilizer (control, liquid organic fertilizer without lemongrass, liquid organic fertilizer + 10% lemongrass, liquid organic fertilizer + 20% lemongrass and liquid organic fertilizer + 30% lemongrass respectively at doses of 0, 6, 12 and 18 ppm. The parameters measured were odor (NH3 and H2S, levels of macro nutrients (N, P, K, Ca, Mg, and S and micro nutrients (Cu, Zn, Mn, and Fe after fermenting process, and the production of crops (fruit number and fruit weight after planting. Research results show that the higher dose of lemongrass added cause levels of odor (NH3 and H2S in the liquid organic fertilizer decreased and content of macro nutrients, micro nutrients, and phytohormones increased. The planting results indicate liquid organic fertilizer which added 20% lemongrass in a dose of 12 ppm was the optimal dose in increasing crop production. Penelitian penggunaan sereh (Cymbopogon citratus dalam menurunkan bau pada pupuk organik cair telah dilakukan di Bogor selama 6 bulan. Penelitian ini diawali dengan membuat pupuk organik cair yang dihasilkan dari 1 kg limbah udang, 1 kg jagung, 1 kg touge, 10 Liter air kelapa, 500 ml EM4 dan 500 g gula pasir melalui proses fermentasi selama 6 minggu. Kemudian pada

  10. Etude des propriétés anti-oxydantes, anti-inflammatoires, anti-prolifératives et anti-migratoires des huiles essentielles de quelques plantes médicinales du Burkina Faso sur des lignées cellulaires du cancer de la prostate et de glioblastomes

    OpenAIRE

    Bayala, Bagora

    2014-01-01

    Essential oils are natural complex of volatile and odorous molecules, synthesized by aromatic plants. They have anti-infective, antioxidant, anticancer properties... The present work concerned the chemical composition, antioxidant, anti-inflammatory and anticancer propertiesof essential oils of Cymbopogon giganteus Chiov., Cymbopogon citratus [DC] Stapf, Ocimum basilicum Linnæus, Ocimum americanum Linnæus, Hyptis spicigera Lamarck, Lippia multiflora Moldenk, Ageratum conyzoides Linnæus, Eucal...

  11. Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii

    OpenAIRE

    Joyce, Blake L.; Zheljazkov, Valtcho D.; Robert Sykes; Cantrell, Charles L.; Choo Hamilton; David G J Mann; Miguel Rodriguez; Mielenz, Jonathan R; Tess Astatkie; C. Neal Stewart

    2015-01-01

    Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass). Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting...

  12. 2666-IJBCS-Article-Adama Denou

    African Journals Online (AJOL)

    hp

    inflammation et la douleur. L'objectif du présent travail était d'évaluer l'effet analgésique de Cymbopogon citratus (DC) Stapf.,. Cleome viscosa Linn., Mitragyna inermis (Willd.) O. Kuntze et Sclerocarya birrea (A. rich.) Hochst utilisées dans la prise ...

  13. Study of the chemical composition of essential oils and floral waters ...

    African Journals Online (AJOL)

    This work aimed to study the chemical composition of essential oils and floral waters of Cymbopogon citratus (DC.) Stapf (Poaceae) from Senegal. The plants were collected in two different localities, Dakar and Kaolack. The extracts were obtained by steam distillation from both fresh and dried plants and analyses carried ...

  14. Effects of two in-organic fertilizers on volatile oil and biomass yields ...

    African Journals Online (AJOL)

    Cymbopogon citratus (DC) Stapf (Poaceae) was cultivated in a randomized completely block design experiment, (RCBD) in Ile-Ife, Nigeria. Effects of two inorganic fertilizers on the oil yield and biomass production were evaluated. NPK (4.63ml/kg and 3.91ml/kg at 12 and 24 weeks respectively) application leads to higher oil ...

  15. Bidirectional DC/DC Converter

    Science.gov (United States)

    Pedersen, F.

    2008-09-01

    The presented bidirectional DC/DC converter design concept is a further development of an already existing converter used for low battery voltage operation.For low battery voltage operation a high efficient low parts count DC/DC converter was developed, and used in a satellite for the battery charge and battery discharge function.The converter consists in a bidirectional, non regulating DC/DC converter connected to a discharge regulating Buck converter and a charge regulating Buck converter.The Bidirectional non regulating DC/DC converter performs with relatively high efficiency even at relatively high currents, which here means up to 35Amps.This performance was obtained through the use of power MOSFET's with on- resistances of only a few mille Ohms connected to a special transformer allowing paralleling several transistor stages on the low voltage side of the transformer. The design is patent protected. Synchronous rectification leads to high efficiency at the low battery voltages considered, which was in the range 2,7- 4,3 Volt DC.The converter performs with low switching losses as zero voltage zero current switching is implemented in all switching positions of the converter.Now, the drive power needed, to switch a relatively large number of low Ohm , hence high drive capacitance, power MOSFET's using conventional drive techniques would limit the overall conversion efficiency.Therefore a resonant drive consuming considerable less power than a conventional drive circuit was implemented in the converter.To the originally built and patent protected bidirectional non regulating DC/DC converter, is added the functionality of regulation.Hereby the need for additional converter stages in form of a Charge Buck regulator and a Discharge Buck regulator is eliminated.The bidirectional DC/DC converter can be used in connection with batteries, motors, etc, where the bidirectional feature, simple design and high performance may be useful.

  16. DC + RSL

    DEFF Research Database (Denmark)

    Haxthausen, Anne

    1996-01-01

    This document gives some initial ideas of how the Duration Calculus (DC) can be integrated with the RAISE Specification Language (RSL).......This document gives some initial ideas of how the Duration Calculus (DC) can be integrated with the RAISE Specification Language (RSL)....

  17. Purificação do oleo essencial de "Cymbopogon Citratus" para a concentração de citral utilizando a destilação molecular

    OpenAIRE

    Laura Plazas Tovar

    2008-01-01

    Resumo: Os óleos essenciais são extratos concentrados de plantas aromáticas constituídos por substâncias orgânicas voláteis, formando uma mistura complexa de hidrocarbonetos terpênicos e derivados oxigenados, havendo sempre a predominância de um ou dois deles, constituindo o(s) principal(is) componente(s) bioquímico(s) de ação terapêutica e responsáveis pelas características organolépticas. O óleo essencial de Capim-Limão, conhecido internacionalmente como óleo essencial ''lemongrass” e de...

  18. Evaluation de la toxicité des huiles essentielles de Cymbopogon ...

    African Journals Online (AJOL)

    Evaluation de la toxicité des huiles essentielles de Cymbopogon nardus (L) et Ocimum gratissimum (L) contre Sitophilus zeamais Motsch et Rhyzopertha dominica F, les principaux insectes nuisibles au maïs en stockage...

  19. DC electric springs with DC/DC converters

    DEFF Research Database (Denmark)

    Wang, Qingsong; Cheng, Ming; Jiang, Yunlei

    2016-01-01

    The concept of DC electric spring (DCES) was recently proposed to solve the stability issue caused by integrating intermittent renewable energy sources (RESs) to DC microgrids. In this paper, a new topology of DCES is proposed based on DC/DC converters. The proposed DCES consists of a bi-directio......The concept of DC electric spring (DCES) was recently proposed to solve the stability issue caused by integrating intermittent renewable energy sources (RESs) to DC microgrids. In this paper, a new topology of DCES is proposed based on DC/DC converters. The proposed DCES consists of a bi...

  20. A report on identification of sequence polymorphism in barcode region of six commercially important Cymbopogon species.

    Science.gov (United States)

    Bishoyi, Ashok Kumar; Kavane, Aarti; Sharma, Anjali; Geetha, K A

    2017-02-01

    CYMBOPOGON: is an important member of grass family Poaceae, cultivated for essential oils which have greater medicinal and industrial value. Taxonomic identification of Cymbopogon species is determined mainly by morphological markers, odour of essential oils and concentration of bioactive compounds present in the oil matrices which are highly influenced by environment. Authenticated molecular marker based taxonomical identification is also lacking in the genus; hence effort was made to evaluate potential DNA barcode loci in six commercially important Cymbopogon species for their individual discrimination and authentication at the species level. Four widely used DNA barcoding regions viz., ITS 1 & ITS 2 spacers, matK, psbA-trnH and rbcL were taken for the study. Gene sequences of the same or related genera of the concerned loci were mined from NCBI domain and primers were designed and validated for barcode loci amplification. Out of the four loci studied, sequences from matK and ITS spacer loci revealed 0.46% and 5.64% nucleotide sequence diversity, respectively whereas the other two loci i.e., psbA-trnH and rbcL showed 100% sequence homology. The newly developed primers can be used for barcode loci amplification in the genus Cymbopogon. The identified Single Nucleotide Polymorphisms from the studied sequences may be used as barcodes for the six Cymbopogon species. The information generated can also be utilized for barcode development of the genus by including more number of Cymbopgon species in future.

  1. Step-Up DC-DC converters

    DEFF Research Database (Denmark)

    Forouzesh, Mojtaba; Siwakoti, Yam P.; Gorji, Saman A.

    2017-01-01

    on the general law and framework of the development of next-generation step-up dc-dc converters, this paper aims to comprehensively review and classify various step-up dc-dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage...

  2. Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii.

    Directory of Open Access Journals (Sweden)

    Blake L Joyce

    Full Text Available Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1 to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2 to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass. Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha-1 respectively compared to reported 1749-3691 L ethanol ha-1 for switchgrass. Pretreated lemongrass yielded 198 mL ethanol (g biomass-1 and pretreated palmarosa yielded 170 mL ethanol (g biomass-1. Additionally, lemongrass yielded 85.7 kg essential oil ha-1 and palmarosa yielded 67.0 kg ha-1 with an estimated value of USD $857 and $1005 ha-1. These data suggest that dual-use crops such as lemongrass and palmarosa may increase the economic viability of lignocellulosic biofuels.

  3. Chemical Fingerprinting of the Fragrant Volatiles of Nineteen Indian Cultivars of Cymbopogon Spreng. (Poaceae

    Directory of Open Access Journals (Sweden)

    Rajendra C. Padalia

    2011-01-01

    Full Text Available The essential oil compositions of total nineteen cultivars of Cymbopogon Spreng. (Poaceae species viz. C. martinii (Roxb. Wats. var. motia Burk., C. flexuosus Nees ex Steud, C. winterinus Jowitt., C. pendulus Nees ex Steud. and a hybrid of C. khasianus (Hack Stapf. ex Bor and C. pendulus Nees ex Steud. were examined and compared using capillary GC and GC-MS . The analysis led to the identification of 48 constituents forming 90.1% to 99.7% of their total oil compositions with monoterpenoids (78.9% to 97.4% as the most exclusive constituents. The comparative results showed considerable variation in the qualitative and quantitative compositions of essential oils from nineteen different cultivars of the studied Cymbopogon species. On the basis of chemical similarity the cultivars of genus Cymbopogon was divided into five chemical variants/groups within two series viz. Citrati and Rusae. The volatile profile of existing cultivars of Cymbopogon are useful for their commercial utilization as they possess range of essential oils and aroma chemicals used in perfumery, flavour, pharmaceutical and other allied industries. Moreover, the marker constituents in their essential oils may be utilized as an important tool in oil authentication.

  4. A resonant dc-dc power converter assembly

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a resonant DC-DC power converter assembly comprising a first resonant DC-DC power converter and a second resonant DC-DC power converter having identical circuit topologies. A first inductor of the first resonant DC-DC power converter and a second inductor of the s......The present invention relates to a resonant DC-DC power converter assembly comprising a first resonant DC-DC power converter and a second resonant DC-DC power converter having identical circuit topologies. A first inductor of the first resonant DC-DC power converter and a second inductor...

  5. DC Home Appliances for DC Distribution System

    Directory of Open Access Journals (Sweden)

    MUHAMMAD KAMRAN

    2017-10-01

    Full Text Available This paper strengthens the idea of DC distribution system for DC microgrid consisting of a building of 50 apartments. Since the war of currents AC system has been dominant because of the paucity of research in the protection of the DC system. Now with the advance research in power electronics material and components, generation of electricity is inherently DC as by solar PV, fuel cell and thermoelectric generator that eliminates the rectification process. Transformers are replaced by the power electronics buck-boost converters. DC circuit breakers have solved the protection problems for both DC transmission and distribution system. In this paper 308V DC microgrid is proposed and home appliances (DC internal are modified to operate on 48V DC from DC distribution line. Instead of using universal and induction motors in rotary appliances, BLDC (Brushless DC motors are proposed that are highly efficient with minimum electro-mechanical and no commutation losses. Proposed DC system reduces the power conversion stages, hence diminishes the associated power losses and standby losses that boost the overall system efficiency. So in view of all this a conventional AC system can be replaced by a DC system that has many advantages by cost as well as by performance

  6. In vitro susceptibility testing of Yersinia species to eight plant ...

    African Journals Online (AJOL)

    AJL

    2012-05-24

    May 24, 2012 ... 10010 Afr. J. Biotechnol. Table 1. The inhibitory effect of neat ethanolic plant extracts and some natural antimicrobials against Yersinia sp. Extract. Diameter of zones of inhibition (mm). YPS. YE 0:3. YE 0:8. YK 0:11, 23. YI 0:52, 53 YIL 0:52, 53. Cymbopogon citratus (DC) staft leaves. 12.7. 16.5. 10.4*. 14.4.

  7. PENENTUAN WAKTU PENYULINGAN DARI SEREH WANGI (CYMBOPOGON NARDUS L. Rendle UNTUK MEMPEROLEH KADAR MAKSIMAL MINYAK ATSIRI

    Directory of Open Access Journals (Sweden)

    Ida Diana Sari

    2012-10-01

    Full Text Available This research conduct to determination of Volatile Oil and citral level from lemon grass (Cymbopogon nardus L. Rendle in the based of refening destillation time (1 to 4 hours. Destillation of Volatile Oil had been carried but by direct steam destillation and citral level was measured by Chromatography Gas. The results showed that refining destillation time give significant differential of Volatile Oil and citral level. Whereas the highest Volatile Oil (0,32% and citral level (36,70% showed at the first, and the lowest showed in the fourth (0,02% and 18,70% of refining destillation time hours. In this observation showed that the increase of refining destillation time, give decrease of Volatile Oil and citral level.   Keyword : Cymbopogon nardus L. Rendle, Poaceae, destillation time, Volatile Oil, Citral

  8. Soft switched DC-DC converter

    Science.gov (United States)

    Subramanian, K.; Kavitha, K. V. N.; Saravanan, K.

    2017-11-01

    A soft switched single switch isolated dc-dc conveys proposed in this paper. This converter works on the principle of zero current switching (zcs) and zero voltage switching (zvs). The circuit comprises lossless snubber with low rating. The switch works on zcs during turn on and zvs during turnoff. The diodes are based on zcs turn on and turnoff conditions. This paper presents the concept of soft switching and its applications to dc-dc converter. The losses due to soft switching and hard switching are compared.

  9. IGBT Based DC/DC Converter

    Directory of Open Access Journals (Sweden)

    M. Akherraz

    1997-12-01

    Full Text Available This paper presents an in-depth analytical and experimental investigation of an indirect DC-DC converter. The DC-AC conversion is a full bridge based on IGBT power modules, and the AC-DC conversion is done via a high  frequency AC link and a first diode bridge. The AC link, which consists of snubbing capacitors and a variable air-gap transformer, is analytically designed to fulfill Zero Voltage commutation requirement. The proposed converter is simulated using PSPICE and a prototype is designed built and tested in the laboratory. PSPICE simulation and experimental results are presented and compared.

  10. Antifungal Effect of Plant Essential Oils on Controlling Phytophthora Species

    National Research Council Canada - National Science Library

    Amini, Jahanshir; Farhang, Vahid; Javadi, Taimoor; Nazemi, Javad

    2016-01-01

    In this study, antifungal activity of essential oils of Cymbopogon citratus and Ocimum basilicum and two fungicides Mancozeb and Metalaxyl-Mancozeb in six different concentrations were investigated...

  11. 76 FR 31462 - Airworthiness Directives; The Boeing Company Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10...

    Science.gov (United States)

    2011-06-01

    ... Model DC-10-10, DC- 10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... Applicability (c) This AD applies to all The Boeing Company Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10- 40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F airplanes...

  12. Effect of plant extracts and an essential oil on the control of brown spot disease, tillering, number of panicles and yield increase in rice

    DEFF Research Database (Denmark)

    Nguefack, Julienne; Wulff, Ednar Gadelha; Dongmo, J. Blaise Lekagne

    2013-01-01

    The effects of essential oils (EO), cold water (CWE), hot water (HWE) and ethanol (ETHE) extracts of Callistemon citrinus L. and Cymbopogon citratus (DC) Stapf on the radial growth of Alternaria padwickii (Ganguly) M.B. Ellis and Bipolaris oryzae (Breda de Haan) Shoemaker, the control of brown sp......, we concluded that the EO and solvent extracts of C. citrinus and C. citratus have potential as control agents against brown spot and other seed-borne fungal diseases in rice under both conventional and organic farming.......The effects of essential oils (EO), cold water (CWE), hot water (HWE) and ethanol (ETHE) extracts of Callistemon citrinus L. and Cymbopogon citratus (DC) Stapf on the radial growth of Alternaria padwickii (Ganguly) M.B. Ellis and Bipolaris oryzae (Breda de Haan) Shoemaker, the control of brown spot...... disease, the tillering, the number of panicles and the yield increase in rice were evaluated under laboratory and field conditions. In vitro, the growth of both fungi was completely inhibited by the EO of C. citrinus and C. citratus at 4,520 mu g/ml and 452 mu g/ml, respectively. For solvent extracts...

  13. HPLC-Profiles of Tocopherols, Sugars, and Organic Acids in Three Medicinal Plants Consumed as Infusions

    Science.gov (United States)

    Roriz, Custódio Lobo; Barros, Lillian; Carvalho, Ana Maria; Ferreira, Isabel C. F. R.

    2014-01-01

    Pterospartum tridentatum (L.) Willk, Gomphrena globosa L., and Cymbopogon citratus (DC.) Stapf are medicinal plants that require a more detailed chemical characterization, given the importance of their consumption as infusions. Therefore, the individual profiles in tocopherols, free sugars, and organic acids were obtained by high performance liquid chromatography (HPLC) coupled to different detectors (fluorescence, refraction index, and photodiode array, resp.). C. citratus revealed the highest content of α-, and total tocopherols, glucose, sucrose, succinic, and ascorbic acids. P. tridentatum presented the highest fructose and total sugars content. Otherwise, G. globosa showed the highest organic acids concentration. As far as we know, this is the first study reporting the mentioned chemical compounds in G. globosa and C. citratus. PMID:26904623

  14. DC-to-DC switching converter

    Science.gov (United States)

    Cuk, Slobodan M. (Inventor); Middlebrook, Robert D. (Inventor)

    1980-01-01

    A dc-to-dc converter having nonpulsating input and output current uses two inductances, one in series with the input source, the other in series with the output load. An electrical energy transferring device with storage, namely storage capacitance, is used with suitable switching means between the inductances to DC level conversion. For isolation between the source and load, the capacitance may be divided into two capacitors coupled by a transformer, and for reducing ripple, the inductances may be coupled. With proper design of the coupling between the inductances, the current ripple can be reduced to zero at either the input or the output, or the reduction achievable in that way may be divided between the input and output.

  15. Evaluación de la toxicidad subaguda de los aceites esenciales de hierba luisa (Cymbopogon citratus) y cúrcuma (Curcuma longa) en en barbus rosado (Puntius cochonius)

    OpenAIRE

    Nieto Suárez, Viviana del Carmen; Viteri Ruiz, José Andrés

    2015-01-01

    This paper focuses on evaluating the toxicity of two emulsions with essential oils of lemongrass and turmeric pink fish Barbus. Two treatments with two different essential oils, turmeric and lemongrass, with inclusion of low-dose, medium, upper middle and high dose at different times of 24, 48 and 96 hours compared with a control which contained only emulsifier (Tween 20 were established ). Using the statistical test one-way ANOVA with a significance of p 0.05 was reached to determine the ...

  16. Evaluación de los parámetros de crecimiento de alevines de tilapia roja (Oreochromis sp.) con dietas enriquecidas con dos aceites esenciales : cúrcuma (curcuma longa) y hierba luisa (cymbopogon citratus)

    OpenAIRE

    Salazar Almeida, Carlos Gabriel; Flores Vallejo, Carla Pamela

    2015-01-01

    The production of red tilapia (Oreochromis sp.) is a very important industry in the Ecuador, so it is necessary to make constant innovations that help improve productivity. Currently has encouraged the use of natural extracts to enhance the growth and survival of fish. For this purpose it was decided to evaluate the essential oils of Turmeric and Lemongrass added to food in a concentration of 0.4% w / w with 8 experimental units each one with 20 fingerlings, located in the laboratories of the...

  17. Effect of feeding dried sweet orange (Citrus sinensis) peel and lemon grass (Cymbopogon citratus) leaves on growth performance, carcass traits, serum metabolites and antioxidant status in broiler during the finisher phase.

    Science.gov (United States)

    Alzawqari, M H; Al-Baddany, A A; Al-Baadani, H H; Alhidary, I A; Khan, Rifat Ullah; Aqil, G M; Abdurab, A

    2016-09-01

    The current experiment was conducted to evaluate the effects of feeding dried sweet orange peel (SOP) and lemon grass leaves (LGL) as feed additives on broiler growth performance, serum metabolites, and antioxidant status. A total of 192-day-old (Ross 308) broiler chickens were distributed randomly into 4 dietary treatments with 4 replicates per each treatment. The dietary treatments included a control diet without any feed additive (T1), a diet containing 0.8 % SOP (T2), a diet containing 0.8 % LGL (T3), and a diet containing combination of 0.4 % SOP + 0.4 % LGL (T4) was fed during the growth period from 22 to 42 days. Feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR), carcass traits, serum components, and antioxidant status were measured. At the end of the experimental period, the results indicated that supplementation of SOP and LGL alone or in combination did not significantly (P > 0.05) affect BWG, FI, FCR, and carcass characteristics in broiler chickens. Serum total protein was increased significantly (P < 0.05) in T3 and T4 compared to the other treatments. Also, serum globulin increased significantly (P < 0.05) in the treated groups. Serum glucose, low density lipoprotein, triglyceride, and very low density lipoprotein decreased significantly (P < 0.05) in the treatment groups, while cholesterol and high-density lipoprotein decreased in T2 compared to the other groups. Significantly (P < 0.05) higher total antioxidant status was observed in T2 compared to the other treatments. In conclusion, these results indicate that SOP, LGL, and their combination may positively modify some serum components and the antioxidant status without any beneficial effect on growth performance and carcass traits in broiler chickens.

  18. 75 FR 38943 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-30, DC...

    Science.gov (United States)

    2010-07-07

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10-40F Airplanes AGENCY... propose to adopt a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10- 40, and DC-10-40F airplanes. This proposed AD would require installing a support...

  19. 75 FR 63040 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-30, DC...

    Science.gov (United States)

    2010-10-14

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10-40F Airplanes AGENCY... (b) None. Applicability (c) This AD applies to McDonnell Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10- 40F airplanes, certificated in any category...

  20. A comparative assessment of the the nutritional contents of 'wara' a ...

    African Journals Online (AJOL)

    The processing line of West African soft cheese varieties (processed with Calotropis procera (Sodom apple) and Cymbopogon citratus (lemon grass) leaf extracts ... The study suggests the use of Cymbopogon citratus leaf extract as a local milk coagulant due to reports of probable health hazard from the use of C. procera.

  1. Phythochemical screening and anticonvulsant activity of Cymbopogon winterianus Jowitt (Poaceae) leaf essential oil in rodents.

    Science.gov (United States)

    Quintans-Júnior, L J; Souza, T T; Leite, B S; Lessa, N M N; Bonjardim, L R; Santos, M R V; Alves, P B; Blank, A F; Antoniolli, A R

    2008-08-01

    Cymbopogon winterianus (Poaceae) is used for its analgesic, anxiolytic and anticonvulsant properties in Brazilian folk medicine. This report aimed to perform phythochemical screening and to investigate the possible anticonvulsant effects of the essential oil (EO) from fresh leaves of C. winterianus in different models of epilepsy. The phytochemical analysis of EO showed presence of geraniol (40.06%), citronellal (27.44%) and citronellol (10.45%) as the main compounds. A behavioral screening demonstrated that EO (100, 200 and 400mg/kg; ip) caused depressant activity on CNS. When administered concurrently, EO (200 and 400mg/kg, ip) significantly reduced the number of animals that exhibited PTZ- and PIC-induced seizures in 50% of the experimental animals (p400mg/kg, ip) significantly increased (p<0.05) the latencies of clonic seizures induced by STR. Our results demonstrated a possible activity anticonvulsant of the EO.

  2. Three new DC-to-DC Single-Switch Converters

    Directory of Open Access Journals (Sweden)

    Barry W. Williams

    2017-06-01

    Full Text Available This paper presents a new family of three previously unidentified dc-to-dc converters, buck, boost, and buck-boost voltage-transfer-function topologies, which offer advantageous transformer coupling features and low capacitor dc voltage stressing. The three single-switch, single-diode, converters offer the same features as basic dc-to-dc converters, such as the buck function with continuous output current and the boost function with continuous input current. Converter time-domain simulations and experimental results (including transformer coupling support and extol the dc-to-dc converter concepts and analysis presented.

  3. Three new DC-to-DC Single-Switch Converters

    OpenAIRE

    Barry W. Williams; Mona Fouad Moussa

    2017-01-01

    This paper presents a new family of three previously unidentified dc-to-dc converters, buck, boost, and buck-boost voltage-transfer-function topologies, which offer advantageous transformer coupling features and low capacitor dc voltage stressing. The three single-switch, single-diode, converters offer the same features as basic dc-to-dc converters, such as the buck function with continuous output current and the boost function with continuous input current. Converter time-domain simulations ...

  4. 75 FR 68246 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-11-05

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F... to supersede an existing airworthiness directive (AD) that applies to all Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10- 10F, MD-10-30F, MD-11...

  5. 75 FR 20790 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-04-21

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F... (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC- 10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F airplanes. This proposed AD would require...

  6. 75 FR 23571 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-05-04

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD...

  7. 75 FR 60602 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-10-01

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD...

  8. Three-port DC-DC converter with new integrated transformer for DC Distribution Systems

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Andersen, Michael A. E.

    2014-01-01

    A new integrated transformer for three-port dc-dc converter is proposed to overcome the power coupling effect existed in some known multiple inputs dc-dc converters. Orthogonal primary windings arrangement and in series connection of diagonal secondary Windings enables a fully power decoupling...

  9. Overview of Multi-DC-Bus Solutions for DC Microgrids

    DEFF Research Database (Denmark)

    Ricchiuto, D.; Mastromauro, R.A.; Liserre, Marco

    2013-01-01

    DC Microgrids have recently received a lot of attention in the last years due to high penetration of renewable energy sources as well as distributed energy storage systems. In the future DC microgrids could be preferable respect to AC microgrids in terms of redundancy since multi-DC-Bus solutions...... could provide a continuative power supply to the loads. An overview of Multi-DC-Bus solutions is presented in this paper. The performances are compared on the basis of possible DC microgrid configurations, redundancy, different DC voltage levels....

  10. DC arc weld starter

    Science.gov (United States)

    Campiotti, Richard H.; Hopwood, James E.

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  11. Early Oscillation Detection for DC/DC Converter Fault Diagnosis

    Science.gov (United States)

    Wang, Bright L.

    2011-01-01

    The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.

  12. 75 FR 6160 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-02-08

    ... Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F Airplanes AGENCY: Federal Aviation... airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC- 10A and...

  13. Anioxidant activity of palmarosa essential oil (Cymbopogon martini grown in north indian plains

    Directory of Open Access Journals (Sweden)

    Kapil Lawrence

    2012-10-01

    Full Text Available Objective: The present study deals with the in vitro study of antioxidant activity of essential oil from Palmarosa (Cymbopogon martini of family gramineae. Methods: The in vitro study of antioxidant activity of Palmarosa essential oil has been done by using DPPH assay,Nitrogen Oxide assay , reducing power assay, 毬 -carotene bleaching assay and FRAP method. Results: IC 50 values observed for DPPH and NO assay are 0.125 mg/ml and 12.5 毺 g/ml respectively.In beta carotene bleaching method the oil showed 93.15% bleaching for the first hour and it increased to 51.1% in second hour. There was a constant increase in the reducing activities with the increase in concentrations in both reducing activity and FRAP mehods. In all the methods BHT and Gallic acid were kept as standards. Conclusions: The results clearly indicate that Palmarosa essential oil is effective in scavanging free radical and has the potential to be powerful antioxidant An essential oil is a liquid that is generally distilled (more frequently by steam or water from the leaves, stems, flowers, bark or roots or other elements of the plant [1]. These are also known as volatile or ethereal oils. Medicinal applications of essential oils range from skin treatment to remedies for cancer.

  14. Effective Control of Postprandial Glucose Level through Inhibition of Intestinal Alpha Glucosidase by Cymbopogon martinii (Roxb.

    Directory of Open Access Journals (Sweden)

    Varsha Ghadyale

    2012-01-01

    Full Text Available Inhibition of intestinal alpha glucosidase plays a major role in preventing rise in postprandial glucose level in diabetics. Cymbopogon martinii (CM (family Poaceae is used in traditional Indian medicine in treatment of diabetes mellitus. The alpha glucosidase inhibitory action of the plant is studied. The active component was separated using hot water extraction of the whole plant powder, differential solvent extraction, and silica gel column chromatography. The 30 : 70 toluene : ethyl acetate fraction showed optimum activity. The silica gel chromatography fraction demonstrated 98, 98, and 68% inhibition for starch, maltose, and sucrose, respectively, at 5 mg/kg body weight of rats. Intestinal absorption studies using noneverted intestinal sacs, as well as in vivo studies in streptozotocin-induced diabetic rats using oral glucose tolerance with maltose and sucrose load, revealed better inhibition of alpha glucosidase as compared to acarbose. Kinetic studies using Lineweaver Burk plot showed mixed to noncompetitive type of inhibition by CM. In vivo studies with maltose load of 2 mg and 3 mg/gm body weight showed a noncompetitive pattern of inhibition at 5 mg/kg body weight of CM as against 60 mg/kg body weight of acarbose. Thus CM is more effective alpha glucosidase inhibitor and at lower concentration than acarbose.

  15. Use of Lippia rotundifolia and Cymbopogon flexuosus essential oils, individually or in combination, in broiler diets

    Directory of Open Access Journals (Sweden)

    Izabela Lorena Azevedo

    Full Text Available ABSTRACT This study investigated the effects of Cymbopogon flexuosus and Lippia rotundifolia microencapsulated essential oils on broiler performance and carcass yield. One hundred and fifty mixed-sex Cobb broiler chicks were used, from one day up to 42 days of age, in a completely randomized design, with five treatments and three replicates of ten birds each. The treatments were: negative control (basal diet, positive control (diet with enramycin and salinomycin, and three diets with microencapsulated essential oils from lemongrass, L. rotundifolia, and combination with 50% of both. The performance and carcass yield were not affected by the treatments. The intestine absolute weight was lower in the combination treatment compared with the negative control treatment and the lemongrass essential oil. The intestine relative weight was higher in the treatments with lemongrass and L. rotundifolia essential oils in relation to the combination. The liver relative weight was lower with the lemongrass essential oil and the combination compared with the treatment with the L. rotundifolia essential oil. The trial could not find results enough to recommend the use of the lemongrass and L. rotundifolia essential oils as an additive in broiler diets.

  16. A Study on Antimicrobial Activities of Essential Oils of Different Cultivars of Lemongrass (Cymbopogon flexuosus

    Directory of Open Access Journals (Sweden)

    Ashish Kumar Gupta, Ritam Muhury, Deepak Ganjewala

    2016-10-01

    Full Text Available Background: Cymbopogon flexuosus popularly known as lemongrass provides a lemon scented essential oil which is widely used in flavour and fragrance, perfumery, food and pharmaceuticals. The aim of the present study was to assess antimicrobial activities of essential oils of three lemongrass cultivars viz., Pragati, Praman and Suvarna. Methods: Essential oils were isolated from one month old plants by hydro-distillation in mini Clevenger apparatus for 2 h. Antimicrobial activities were determined by agar well diffusion method Results: Lemongrass oils exhibited strong antimicrobial activity against all the microbes except E coli. Mean inhibition zone diameter (mm against bacteria was ranged 27-38 mm. B. Subtilis was the most sensitive bacterium to all essential oils. Essential oils also showed strong antifungal effects against both A. niger and C. albicans with mean inhibition zone diameter (mm values 20-26 and 27-29 mm, respectively. Statistical analyses revealed that antimicrobial activity shown by essential oils were significant (p > 0.05. Conclusion: The study revealed strong antimicrobial potential of the essential oil against pathogenic microbial strains which may be of high clinical importance in future.

  17. Ethanol extract of Cymbopogon winterianus on mortality and number of eggs of Tetranychus urticae

    Directory of Open Access Journals (Sweden)

    Victor Bernardo Vicentini

    2015-07-01

    Full Text Available Plant extracts have been studied as a promising source of natural insecticides. This study assessed the effect of the ethanol extract of Cymbopogon winterianus Jowitt (citronella grass in comparison with an insecticide containing azadirachtin (ICA on mortality and number of eggs of Tetranychus urticae Koch (Acari: Tetranychidae in laboratory conditions. For the tests, the mites were sprayed with the aid of a Potter spray tower. To assess the mortality of females, LC50 value for extract of citronella grass and ICA was, respectively, 2.63 and 2.83%. With respect to the number of eggs, the greatest reduction was observed at a concentration of 5% for the evaluation period of 120h, both for the extract of citronella grass (86% and for ICA (81%. These results suggest the potential of the ethanol extract of citronella grass to control of T. urticae. However, experiments, under field conditions, involving other populations of T. urticae should be performed to verify the efficacy of this extract as an alternative to be used in pest management programs

  18. PERBANDINGAN KANDUNGAN MINYAK ATSIRI TANAMAN SEREH WANGI (Cymbopogon nardus L. Rendle YANG DITANAM DI LOKASI BERBEDA

    Directory of Open Access Journals (Sweden)

    Margareta Dacosta

    2017-03-01

    Full Text Available It has been conducted a research that aims to determine the ratio of essential oil content of citronella stalks (Cymbopogon nardus Rendle L. grown in the lowlands of Denpasar and the highlands of Bedugul. The experiment was conducted by using experimental designs. The parameters measured were the volume and the level of citronella oil produced. The sample preparation of powdered citronella stalks was as much as 200 grams, macerated with 96% ethanol and evaporated with Vacuum rotary evaporator to form condensed extract. The research used quantitative methods. The volume of hydro distillation was to obtain a crude extract of citronella stalks and the identification of active compounds was conducted by using Gas Chromatography / Mass Spectrometry (GC-MS. It can be concluded that the levels of citronella essential oil stalks from the highland of Bedugul was higher than the lowland areas of Denpasar, while the quality of essential oil of the lowland of Denpasar was better than that of the Bedugul highland. The content of secondary metabolites of the results of GC-MS analysis obtained from the essential oils contained in the analyzed crude extract of citronella stalks namely the compound of Selina-6-en-4-ol (2287322, the compound of n-hexadecanoic acid (1238019 and the compound of Driman-8,11-diol from the lowland of Denpasar while the Selina compound-6-en-4-ol (1856137 from the highland of Bedugul. Keywords: Citronella, essential oil content, altitude

  19. Influence of season, harvest time and drying on Java citronella (Cymbopogon winterianus Jowitt volatile oil

    Directory of Open Access Journals (Sweden)

    Arie F. Blank

    Full Text Available Java citronella (Cymbopogon winterianus Jowitt is member of the Poaceae family. Java citronella volatile oil has been reported to be among the volatile oils, showing repellent, antimycotic, and acaricide activities. It has been known that agronomical factors have a great effect on both the quality and quantity of essential metabolites. For this reason, it is necessary to determine optimum levels of agronomical factors affecting plant growth and production. Harvest time and drying are very important agronomical factors. This study has been conducted in the Research farm of the " Universidade Federal de Sergipe" , Agronomical Engineering Department along 2002-2003 on the base of factorial experiment in randomized complete block design with three replications. Java citronella was cultivated in a 60 x 60 cm space. Early, midday, and late harvest at 9:00 h, 12:00 h, and 15:00 h were conducted on four different seasons. Fresh and dried leaves were used on the experiments. In order to study the effects of harvest time and drying, yields of dry and fresh herbage (kg/ha, moisture content (%, volatile oil content (% and yield (L/ha, and chemical composition of the volatile oil were measured. Seasonal changes had significant effect on yield of fresh herbage, yield and volatile oil content. Maximum volatile oil yields were observed at 9:00 during summer, winter, and spring. Volatile oil content was influenced by season and drying, but not influenced by harvest time.

  20. Phenotypic recurrent selection on herb growth yield of citronella grass (Cymbopogon nardus grown in Egypt

    Directory of Open Access Journals (Sweden)

    MOHAMED M. IBRAHIM

    2013-11-01

    Full Text Available Ibrahim MM,Khalid KA. 2013. Phenotypic recurrent selection on herb growth yield of citronella grass (Cymbopogon nardus grown in Egypt. Nusantara Bioscience 5: 68-72. This investigation was conducted in four generations: base population (G0, G1, G2 and G3 (clone selection generation to evaluate the genetic variability of citronella clones. Thirteen clones were selected from base population to study the herb growth yield characters and oil production as well as genetic parameters, correlation and regression. Results were recorded for herb growth characters (i.e. plant high (PH, no. of tillers (NOT, dry yield (DY, viability percentage (VP and oil production. Significant variation was observed among citronella clones in base population for most studied traits. Wide range of mean values was observed among the characters for generations and cuts in most of traits. High heritability values (0.95, 0.93, 0.89 and 0.72 were estimated in NOT, LG, HY and VP., respectively. Clone code no. 39/3, 17/4 and 8/1 gave highest values of dry weight, oil yield and viability percentage. Selected clones showed significant positive regression and correlation between dry weight and each of number of tillers and linear growth. On contrary, viability percentage had significant negative correlation and regression with other characters. These results raveled high yielding selected citronella clones will be utilized in medicinal plant breeding program.

  1. Design of a kilowatt DC-DC converter

    Directory of Open Access Journals (Sweden)

    Liu Hongxing

    2017-01-01

    Full Text Available In view of the low power of traditional DC-DC converters, a DC-DC converter with a kilowatt power is designed. The input signal's frequency is 1 kHz and the duty cycle is 5%. The PWM signal controls the high-speed conduction or cut-off of the switch tube. The input DC voltage is 36V, and the output voltage is twice as high as the input voltage. The output power is greater than 1 KW; the circuit conversion efficiency is 87.21%.

  2. DC micro-grids

    OpenAIRE

    Mia, Gredelj

    2014-01-01

    The conventional electrical system in place today sees our electrical devices powered by AC mains. But as renewable technologies such as solar photovoltaic and wind power become more prevalent at a household level, DC micro-grids could be a cheaper and more efficient alternative. New lighting devices (LED) can reduce the electricity consumption substantially. Two alternatives are envisioned in this paper: A stand-alone alternative in which there is no grid connection, that would require local...

  3. Dynamic Evolution Control for Fuel Cell DC-DC Converter

    Directory of Open Access Journals (Sweden)

    Ahmad Saudi Samosir

    2011-04-01

    Full Text Available Fuel cells are new alternative energy resource that has a great promise for distributed generation and electric vehicle application. However, fuel cells have a slow response due to their slow internal electromechanical and thermodynamic response. To optimize the fuel cell system performance, a fuel cell DC-DC converter with an appropriate controller which can regulate the power flow and automatically adjust the converter output voltage is needed. This paper proposes a new control technique for fuel cell DC-DC power converter. Design of the proposed control method for fuel cell DC-DC power converter is provided. A new approach for converter controllers synthesis based on dynamic evolution control theory is presented. In this paper, synthesis example of boost DC-DC converter is discussed. Performance of the proposed dynamic evolution control under step load variation condition is simulated under Matlab-Simulink environment. Simulation results show that the proposed techniques are capable for controlling fuel cell DC-DC converter.

  4. Synergism between essential oils and antimicrobial drugs against Staphylooccus aureus and Escherichia coli strains from human infections

    OpenAIRE

    Zago, Juliana A. A.; Ushimaru, Priscila I.; Barbosa, Lidiane N.; Fernandes Junior, Ary

    2009-01-01

    Estudos com plantas e utilização em terapias combinatórias têm sido estimulados. Verificou-se as possíveis interações entre óleos essenciais de plantas [canela (Cinnamomum zeylanicum Blume Lauraceae), capim-cidreira (Cymbopogon citratus (DC.) Stapf, Poaceae), hortelã-pimenta (Mentha piperita L. Lamiaceae), gengibre (Zingiber officinale Roscoe Zingiberaceae), cravo-da-índia (Caryophillus aromaticus L. Myrtaceae) e alecrim (Rosmarinus officinalis L. Lamiaceae)] combinados a oito drogas antimicr...

  5. A new optimum topology switching dc-to-dc converter

    Science.gov (United States)

    Cuk, S.; Middlebrook, R. D.

    1977-01-01

    A novel switching dc-to-dc converter is presented, which has the same general conversion property (increase or decrease of the input dc voltage) as does the conventional buck-boost converter, and which offers through its new optimum topology higher efficiency, lower output voltage ripple, reduced EMI, smaller size and weight, and excellent dynamic response. One of its most significant advantages is that both input and output current are not pulsating but are continuous (essentially dc with small superimposed switching current ripple), thus resulting in a close approximation to the ideal physically nonrealizable dc-to-dc transformer. The converter retains the simplest possible structure with the minimum number of components which, when interconnected in its optimum topology, yield the maximum performance.

  6. Antistress Effects of the Ethanolic Extract from Cymbopogon schoenanthus Growing Wild in Tunisia

    Directory of Open Access Journals (Sweden)

    Mahmoud Ben Othman

    2013-01-01

    Full Text Available This study aimed to investigate the antistress properties of the ethanol extract of Cymbopogon schoenanthus (CSEE, growing wild in the southern part of Tunisia. The effect of extracts on H2O2-induced cytotoxicity and stress in human neuroblastoma SH-SY5Y cells. Its effect on stress-induced in ICR mice was exposed to force swim and tail suspension, in concordance with heat shock protein expression (HSP27 and HSP90, corticosterone, and catecholamine neurotransmitters level. Our results demonstrated that pretreatment of SH-SY5Y cells with CSEE at 1/2000, 1/1000, and 1/500 v/v dilutions significantly inversed H2O2-induced neurotoxicity. Moreover, CSEE treatments significantly reversed heat shock protein expression in heat-stressed HSP47-transformed cells (42°C, for 90 min and mRNA expression of HSP27 and HSP90 in H2O2-treated SH-SY5Y. Daily oral administration of 100 mg/kg and 200 mg/kg CSEE was conducted to ICR mice for 2 weeks. It was resulted in a significant decrease of immobility time in forced swimming and tail suspension tests. The effect of CSEE on animal behavior was concordant with a significant regulation of blood serum corticosterone and cerebral cortex levels of catecholamine (dopamine, adrenaline, and noradrenaline. Therefore, this study was attempted to demonstrate the preventive potential of CSEE against stress disorders at in vitro and in vivo levels.

  7. PENGGUNAAN FUZZY LOGIC UNTUK KONTROL PARALLEL CONVERTER DC-DC

    Directory of Open Access Journals (Sweden)

    Bambang Prio Hartono

    2012-09-01

    Full Text Available Abstract: Using system fuzzy logic as control  technology have been used on low load dc-dc converter with combined parallel compiled  dc-dc converter can  obtain big load.   With existence of differrence of component parameter and each parallel compiled converter can obtained different current  and voltage output.  Function of controller  for to do adjustment, so that current which is applied  to  load by each converter  can be obtained  difference error as small as possible or same. The object of research is developing design of large signal dc-dc converter which is  combined with using  FLC so that  obtain  better performance.  To get better performance have been made plant model and simulation with CDE method.  The more systematic  system and design is needed to overcome bigger load  on dc-dc converter, so that parallel  compiled current master slave control system on dc-dc converter with using fuzzy logic  controller is used. Result of  research showed that error or difference of  current  which is applied to load can handled by fuzzy logic  controller.  Technic of current and voltage controller co to do adjustment current and voltage distribution  equally to load.  Distribution of iL1,iL2 and  output voltage Vo on dc-dc  converter with load 2,25 until  7,875 and voltage  100  until 120 volt,  load current beetwen  12 until 48, % relatif  error  Vo  0,4% until  0,9%.

  8. Direct Sensitivity Analysis of the DC-to-DC Converters

    Directory of Open Access Journals (Sweden)

    Elena Niculescu

    2009-05-01

    Full Text Available The mathematical principle of the directsensitivity analysis of the dynamic systems and itsapplication to the DC-to-DC PWM converters arepresented. The model of the dynamic system associatedto the PWM Sepic converter with parasitic includedand continuous conduction mode (CCM, and coupledinductors was used in this study. The modelling of theconverter and the state sensitivity analysis with respectto some parameters of the converter have beenperformed with MATLAB environment. The algorithmcarried out for computing the state sensitivity functionsof converter can be applied to other configurations ofDC-to-DC PWM converters, for the two operatingmodes (CCM and DCM, with parasitic included andwith coupled or separate inductors, regardless ofsystem order.

  9. DC Distribution Systems and Microgrids

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Anvari-Moghaddam, Amjad; Quintero, Juan Carlos Vasquez

    2017-01-01

    A qualitative overview of different hardware topologies and control systems for DC MGs has been presented in this chapter. Some challenges and design considerations of DC protections systems have also been discussed. Finally, applications of DC MGs in emerging smart grid applications have been su...... in different industries and gradually lead to new ways of rethinking of the future power distribution philosophies, especially with the emergence of SSTs. Research in DC systems, especially in the power electronics-based technologies will be highly attractive in the future....

  10. SCM Handbooks for dc-to-dc Converters

    Science.gov (United States)

    Lee, F.; Mohmoud, M.; Yu, Y.

    1984-01-01

    Two documents aid in design of control modules for dc-to-dc converters. Features of SCM include: Adaptive stability, power component stress limiting, implementation of various control laws, unified design approach. Analysis and quidelines contained in handbooks enable engineer to design SCM circuit and confidently predict resulting overall performance.

  11. Dc-To-Dc Converter Uses Reverse Conduction Of MOSFET's

    Science.gov (United States)

    Gruber, Robert P.; Gott, Robert W.

    1991-01-01

    In modified high-power, phase-controlled, full-bridge, pulse-width-modulated dc-to-dc converters, switching devices power metal oxide/semiconductor field-effect transistors (MOSFET's). Decreases dissipation of power during switching by eliminating approximately 0.7-V forward voltage drop in anti-parallel diodes. Energy-conversion efficiency increased.

  12. Early Oscillation Detection Technique for Hybrid DC/DC Converters

    Science.gov (United States)

    Wang, Bright L.

    2011-01-01

    Oscillation or instability is a situation that must be avoided for reliable hybrid DC/DC converters. A real-time electronics measurement technique was developed to detect catastrophic oscillations at early stages for hybrid DC/DC converters. It is capable of identifying low-level oscillation and determining the degree of the oscillation at a unique frequency for every individual model of the converters without disturbing their normal operations. This technique is specially developed for space-used hybrid DC/DC converters, but it is also suitable for most of commercial and military switching-mode power supplies. This is a weak-electronic-signal detection technique to detect hybrid DC/DC converter oscillation presented as a specific noise signal at power input pins. It is based on principles of feedback control loop oscillation and RF signal modulations, and is realized by using signal power spectral analysis. On the power spectrum, a channel power amplitude at characteristic frequency (CPcf) and a channel power amplitude at switching frequency (CPsw) are chosen as oscillation level indicators. If the converter is stable, the CPcf is a very small pulse and the CPsw is a larger, clear, single pulse. At early stage of oscillation, the CPcf increases to a certain level and the CPsw shows a small pair of sideband pulses around it. If the converter oscillates, the CPcf reaches to a higher level and the CPsw shows more high-level sideband pulses. A comprehensive stability index (CSI) is adopted as a quantitative measure to accurately assign a degree of stability to a specific DC/DC converter. The CSI is a ratio of normal and abnormal power spectral density, and can be calculated using specified and measured CPcf and CPsw data. The novel and unique feature of this technique is the use of power channel amplitudes at characteristic frequency and switching frequency to evaluate stability and identify oscillations at an early stage without interfering with a DC/DC converter s

  13. A DC Transformer

    Science.gov (United States)

    Youngquist, Robert C.; Ihlefeld, Curtis M.; Starr, Stanley O.

    2013-01-01

    A component level dc transformer is described in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both de devices, such that the output voltage of a de power supply can be stepped up (or down) with a corresponding step down (or up) in current. The basic theory for this device is developed, performance predictions are made, and the results from a small prototype are presented. Based on demonstrated technology in the literature, this de transformer should be scalable to low megawatt levels, but it is more suited to high current than high voltage applications. Significant development would be required before it could achieve the kilovolt levels needed for de power transmission.

  14. Modular Power System Configured with Standard Product Hybrid DC-DC Converters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — VPT proposes an innovative concept whereby complex, multiple-output, DC-DC converter systems can be configured through use of only 2 standard product hybrid DC-DC...

  15. The in vitro antimicrobial activity of Cymbopogon essential oil (lemon grass) and its interaction with silver ions.

    Science.gov (United States)

    Ahmad, Aijaz; Viljoen, Alvaro

    2015-06-01

    It is well known that Cymbopogon (lemon grass) essential oil exhibits antimicrobial activity while the efficacy of silver ions as a disinfectant is equally well reported. The antimicrobial activity of CEO and Ag(+) and their synergistic combinations will be useful in improving the current treatment strategies for various infections. In the present study, we determined the chemical composition and in vitro antimicrobial activity of six different Cymbopogon essential oils (CEO's) alone and in combination with silver ions (Ag(+)) against two Gram-positive (Staphylococcus aureus and Enterococcus faecalis), two Gram-negative (Escherichia coli and Moraxella catarrhalis) and two yeast species (Candida albicans and Candida tropicalis). The nature of potential interactions was determined by fractional inhibitory concentration indices (FICIs) for CEO's and Ag(+) calculated from microdilution assays and time-kill curves. Gas chromatography-mass spectrometry results confirmed the presence of nerol, geranial and geraniol as major volatile compounds. Minimum inhibitory concentration (MIC) values confirmed that all the tested pathogens are variably susceptible to both CEO's as well as Ag(+). The MIC of CEO's and Ag(+) against all the tested pathogens ranged from 0.032 mg/ml to 1 mg/ml and 0.004 and 0.064 mg/ml respectively, whereas when assayed in combination the FICI values were drastically reduced to range between 0.258 and 2.186, indicating synergy, additive and indifferent interactions. The most prominent interaction was observed between Cymbopogon flexuosus essential oil and Ag(+) against C. albicans with ∑FIC = 0.254. The synergistic interactions were further confirmed through the construction of isobolograms and time-kill plots. Transmission electron microscopy showed disturbance in the cell envelope upon the concomitant treatment of CEO's and Ag(+), which ultimately leads to cell death. Results suggest that CEO's and Ag(+) when used in combination offers an opportunity

  16. Triple voltage dc-to-dc converter and method

    Science.gov (United States)

    Su, Gui-Jia

    2008-08-05

    A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

  17. Bi-Directional DC-DC Converter for PHEV Applications

    Energy Technology Data Exchange (ETDEWEB)

    Abas Goodarzi

    2011-01-31

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  18. Step-Up DC-DC Power Converter

    DEFF Research Database (Denmark)

    2015-01-01

    capacitor coupled between the positive and negative input terminals and the secondary side circuit comprises an output capacitor chargeable to a converter output voltage between a first positive electrode and a second negative electrode. A switched energy storage network is configured for alternatingly...... being charged from the input voltage and discharged to the output capacitor through the galvanic isolation barrier in accordance with a switch control signal to produce the converter output voltage. The step-up DC-DC power converter comprises an electrical short-circuit connection across the galvanic......The present invention relates to a step-up DC-DC power converter which comprises a primary side circuit and a secondary side circuit coupled through a galvanic isolation barrier. The primary side circuit comprises a positive and a negative input terminal for receipt of an input voltage and an input...

  19. Active pre-filters for dc/dc Boost regulators

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Ramos-Paja

    2014-05-01

    Full Text Available This paper proposes an active pre-filter to mitigate the current harmonics generated by classical dc/dc Boost regulators, which generate current ripples proportional to the duty cycle. Therefore, high output voltage conditions, i.e., high voltage conversion ratios, produce high current harmonics that must be filtered to avoid damage or source losses. Traditionally, these current components are filtered using electrolytic capacitors, which introduce reliability problems because of their high failure rate. The solution introduced in this paper instead uses a dc/dc converter based on the parallel connection of the Boost canonical cells to filter the current ripples generated by the Boost regulator, improving the system reliability. This solution provides the additional benefits of improving the overall efficiency and the voltage conversion ratio. Finally, the solution is validated with simulations and experimental results.

  20. Fuzzy Control of DC-DC Converters with Input Constraint

    Directory of Open Access Journals (Sweden)

    D. Saifia

    2012-01-01

    Full Text Available This paper proposes a method for designing fuzzy control of DC-DC converters under actuator saturation. Because linear control design methods do not take into account the nonlinearity of the system, a T-S fuzzy model and a controller design approach is used. The designed control not only handles the external disturbance but also the saturation of duty cycle. The input constraint is first transformed into a symmetric saturation which is represented by a polytopic model. Stabilization conditions for the state feedback system of DC-DC converters under actuator saturation are established using the Lyapunov approach. The proposed method has been compared and verified with a simulation example.

  1. Decentralized Interleaving of Paralleled Dc-Dc Buck Converters

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rodriguez, Miguel [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sinha, Mohit [University of Minnesota; Dhople, Sairaj [University of Minnesota; Poon, Jason [University of California at Berkeley

    2017-08-21

    We present a decentralized control strategy that yields switch interleaving among parallel-connected dc-dc buck converters. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform and no communication between different controllers is needed. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work presents the first fully decentralized strategy for switch interleaving in paralleled dc-dc buck converters.

  2. Decentralized Interleaving of Paralleled Dc-Dc Buck Converters: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rodriguez, Miguel [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sinha, Mohit [University of Minnesota; Dhople, Sairaj [University of Minnesota; Poon, Jason [University of California at Berkeley

    2017-09-01

    We present a decentralized control strategy that yields switch interleaving among parallel connected dc-dc buck converters without communication. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work represents the first fully decentralized strategy for switch interleaving of paralleled dc-dc buck converters.

  3. RESONANT STEP-DOWN DC-DC POWER CONVERTERS

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a resonant step-down DC-DC power converter which comprises a primary side circuit and a secondary side circuit coupled through a galvanic isolation barrier. The primary side circuit comprises a positive and a negative input terminal for receipt of an input voltage...... charged from the input voltage and discharged to the output capacitor through the galvanic isolation barrier by a semiconductor switch arrangement in accordance with a switch control signal to produce the converter output voltage. The resonant step-down DC-DC power converter comprises an electrical short......-circuit connection across the galvanic isolation barrier connecting, in a first case, the second negative electrode of the output capacitor to the positive input terminal of the primary side circuit or, in a second case, connecting the second positive electrode of the output capacitor to the negative input terminal...

  4. DC-Compensated Current Transformer.

    Science.gov (United States)

    Ripka, Pavel; Draxler, Karel; Styblíková, Renata

    2016-01-20

    Instrument current transformers (CTs) measure AC currents. The DC component in the measured current can saturate the transformer and cause gross error. We use fluxgate detection and digital feedback compensation of the DC flux to suppress the overall error to 0.15%. This concept can be used not only for high-end CTs with a nanocrystalline core, but it also works for low-cost CTs with FeSi cores. The method described here allows simultaneous measurements of the DC current component.

  5. DC injection into low voltage AC networks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report summarises the results of a study investigating the impact of levels of injected DC current injections on a low voltage AC distribution network systems in order to recommend acceptable limits of DC from microgeneration. Relevant literature is reviewed, and the impact of DC levels in distribution transformers, transformer modelling, and instrumental transformers are discussed. The impact of DC in residual current devices (RCD) and in domestic electricity watt hour meters is examined along with DC enhanced corrosion, corrosion failure, and the measurement of DC current injection. Sources of DC injection outlined include DC from computer power supplies, network faults, geomagnetic phenomena, lighting circuits/dimmers, and embedded generators.

  6. Digital Control Technologies for Modular DC-DC Converters

    Science.gov (United States)

    Button, Robert M.; Kascak, Peter E.; Lebron-Velilla, Ramon

    2002-01-01

    Recent trends in aerospace Power Management and Distribution (PMAD) systems focus on using commercial off-the-shelf (COTS) components as standard building blocks. This move to more modular designs has been driven by a desire to reduce costs and development times, but is also due to the impressive power density and efficiency numbers achieved by today's commercial DC-DC converters. However, the PMAD designer quickly learns of the hidden "costs" of using COTS converters. The most significant cost is the required addition of external input filters to meet strict electromagnetic interference (MIAMI) requirements for space systems. In fact, the high power density numbers achieved by the commercial manufacturers are greatly due to the lack of necessary input filters included in the COTS module. The NASA Glenn Research Center is currently pursuing a digital control technology that addresses this problem with modular DC-DC converters. This paper presents the digital control technologies that have been developed to greatly reduce the input filter requirements for paralleled, modular DC-DC converters. Initial test result show that the input filter's inductor size was reduced by 75 percent, and the capacitor size was reduced by 94 percent while maintaining the same power quality specifications.

  7. Isolated step-down DC -DC converter for electric vehicles

    Science.gov (United States)

    Kukovinets, O. V.; Sidorov, K. M.; Yutt, V. E.

    2018-02-01

    Modern motor-vehicle industrial sector is moving rapidly now towards the electricity-driving cars production, improving their range and efficiency of components, and in particular the step-down DC/DC converter to supply the onboard circuit 12/24V of electric vehicle from the high-voltage battery. The purpose of this article - to identify the best circuitry topology to design an advanced step-down DC/DC converters with the smallest mass, volume, highest efficiency and power. And this will have a positive effect on driving distance of electric vehicle (EV). On the basis of computational research of existing and implemented circuit topologies of step-down DC/DC converters (serial resonant converter, full bridge with phase-shifting converter, LLC resonant converter) a comprehensive analysis was carried out on the following characteristics: specific volume, specific weight, power, efficiency. The data obtained was the basis for the best technical option - LLC resonant converter. The results can serve as a guide material in the process of components design of the traction equipment for electric vehicles, providing for the best technical solutions in the design and manufacturing of converting equipment, self-contained power supply systems and advanced driver assistance systems.

  8. DC Microgrids – Part I

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Lu, Xiaonan; Quintero, Juan Carlos Vasquez

    2016-01-01

    This paper presents a review of control strategies, stability analysis and stabilization techniques for DC microgrids (MGs). Overall control is systematically classified into local and coordinated control levels according to respective functionalities in each level. As opposed to local control...

  9. Linking DC together with TRSL

    DEFF Research Database (Denmark)

    Haxthausen, Anne Elisabeth; Yong, X.

    2000-01-01

    Duration Calculus (DC) is an interval-based real-time logic, which can be used in capturing and eliciting users' real-time requirements. The Timed RAISE Specification Language (TRSL) is an extension of the RAISE Specification Language with real-time features. This paper links DC and TRSL together...... approach for linking state-based real-time logics together with event-based, timed process algebra languages....

  10. Lemongrass and citral effect on cytokines production by murine macrophages.

    Science.gov (United States)

    Bachiega, Tatiana Fernanda; Sforcin, José Maurício

    2011-09-01

    Cymbopogon citratus (DC) Stapf (Poaceae-Gramineae), an herb commonly known as lemongrass (LG), is an important source of ethnomedicines as well as citral, the major constituent of Cymbopogon citratus, used in perfumery, cosmetic and pharmaceutical industries for controlling pathogens. Thus, the goal of this work was to analyze the effect of LG and citral on cytokines production (IL-1β, IL-6 and IL-10) in vitro, as well as before or after LPS incubation. Peritoneal macrophages from BALB/c mice were treated with LG or citral in different concentrations for 24h. The concentrations that inhibited cytokines production were tested before or after macrophages challenge with LPS, in order to evaluate a possible anti-inflammatory action. Supernatants of cell cultures were used for cytokines determination by ELISA. As to IL-1β, only citral inhibited its release, exerting an efficient action before LPS challenge. LG and citral inhibited IL-6 release. Cymbopogon citratus showed inhibitory effects only after LPS challenge, whereas citral prevented efficiently LPS effects before and after LPS addition. Citral inhibited IL-10 production and although LG did not inhibit its production, the concentration of 100 μg/well was tested in the LPS-challenge protocol, because it inhibited IL-6 production. LG inhibited LPS action after macrophages incubation with LPS, while citral counteracted LPS action when added before or after LPS incubation. LG exerted an anti-inflammatory action and citral may be involved in its inhibitory effects on cytokines production. We suggest that a possible mechanism involved in such results could be the inhibition of the transcription factor NF-κB. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  11. In vitro screening of selected essential oils from medicinal plants ...

    African Journals Online (AJOL)

    , Cymbopogon citratus, Eucalyptus citriodora, Laurus nobilis, Lippia multiflora, Mentha piperita, Ocimum basilicum, Ocimum gratissimum and Zingiber officinalis on enteric methane production in in vitro batch cultures screening experiments ...

  12. In vitro evaluation of the effect of aqueous extracts of Agave sisalana ...

    African Journals Online (AJOL)

    SARAH

    2015-05-30

    May 30, 2015 ... Agave sisalana and Cymbopogon citratus on mycelial growth and conidia ... The plants extracts tested showed antifungal activity. This result should enable ... significant inhibition of Candida albicans when treated with sisal ...

  13. Atmel Microcontroller Based Soft Switched PWM ZVS Full Bridge DC to DC Converter

    Directory of Open Access Journals (Sweden)

    DEEPAK KUMAR NAYAK

    2010-12-01

    Full Text Available This paper deals with the simulation and implementation of soft switched PWM ZVS full bridge DC to DC converter. The 48V DC is efficiently reduced to 12V DC using a DC to DC converter. This converter has advantages like reduced switching losses, stresses and EMI. Input DC is converted into high frequency AC and it is stepped down to 12V level. Later it is rectified using a full wave rectifier. Laboratory model of microcontroller based DC to DC converter is fabricated and tested. The experimental results are compared with the simulation results.

  14. Very High Frequency Half Bridge DC/DC Converter

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    This paper presents the first, off chip, class DE (resonant half bridge) converter working in the Very High Frequency (VHF) range. The benefits of using half bridge circuits both in the inverter and rectifier part of a VHF resonant dc/dc converter are analyzed and design equations for all...... components in the power stage are given. The circuit has been simulated to verify the accuracy of the presented equations and an efficiency of 89% has been shown. A prototype has been implemented with self-oscillating resonant gate drives driving the switches. The prototype has been used to drive an LED...

  15. A SOFT SWITCHED INTERLEAVED HIGH GAIN DC-DC CONVERTER

    Directory of Open Access Journals (Sweden)

    SHESHIDHAR REDDY ADDULA

    2017-09-01

    Full Text Available In this paper, a novel soft-switched interleaved DC-DC converter which provides a high voltage gain of 12 is proposed. Voltage gain of the basic interleaved boost converter is extended by using diode-capacitor multiplier (DCM cells. The switches are operated at a nominal duty ratio of 0.5. The voltage stress on the power switches and diodes is only a fraction of the output voltage. To enhance the operating power conversion efficiency, the switches are turned ON at zero voltage condition. Experimental results of 18-216V, 100W prototype converter validate the operating principle and the advantageous features of the presented converter.

  16. Power flow analysis for DC voltage droop controlled DC microgrids

    DEFF Research Database (Denmark)

    Li, Chendan; Chaudhary, Sanjay; Dragicevic, Tomislav

    2014-01-01

    This paper proposes a new algorithm for power flow analysis in droop controlled DC microgrids. By considering the droop control in the power flow analysis for the DC microgrid, when compared with traditional methods, more accurate analysis results can be obtained. The algorithm verification...... is carried out by comparing the calculation results with detailed time domain simulation results. With the droop parameters as variables in the power flow analysis, their effects on power sharing and secondary voltage regulation can now be analytically studied, and specialized optimization in the upper level...... control can also be made accordingly. Case studies on power sharing and secondary voltage regulation are carried out using proposed power flow analysis....

  17. Pulse-width modulated DC-DC power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2008-01-01

    This book studies switch-mode power supplies (SMPS) in great detail. This type of converter changes an unregulated DC voltage into a high-frequency pulse-width modulated (PWM) voltage controlled by varying the duty cycle, then changes the PWM AC voltage to a regulated DC voltage at a high efficiency by rectification and filtering. Used to supply electronic circuits, this converter saves energy and space in the overall system. With concept-orientated explanations, this book offers state-of-the-art SMPS technology and promotes an understanding of the principle operations of PWM converters,

  18. Light-weight DC to very high voltage DC converter

    Science.gov (United States)

    Druce, R.L.; Kirbie, H.C.; Newton, M.A.

    1998-06-30

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

  19. DC grid for home applications

    Science.gov (United States)

    Elangovan, D.; Archana, R.; Jayadeep, V. J.; Nithin, M.; Arunkumar, G.

    2017-11-01

    More than fifty percent Indian population do not have access to electricity in daily lives. The distance between the power generating stations and the distribution centers forms one of the main reasons for lack of electrification in rural and remote areas. Here lies the importance of decentralization of power generation through renewable energy resources. In the present world, electricity is predominantly powered by alternating current, but most day to day devices like LED lamps, computers and electrical vehicles, all run on DC power. By directly supplying DC to these loads, the number of power conversion stages was reduced, and overall system efficiency increases. Replacing existing AC network with DC is a humongous task, but with power electronic techniques, this project intends to implement DC grid at a household level in remote and rural areas. Proposed work was designed and simulated successfully for various loads amounting to 250 W through appropriate power electronic convertors. Maximum utilization of the renewable sources for domestic and commercial application was achieved with the proposed DC topology.

  20. Linking DC together with TRSL

    DEFF Research Database (Denmark)

    Haxthausen, Anne; Yong, Xia

    1999-01-01

    for high-level specifications of real-time requirementsand TRSL for specifying real-time implementations in the form of timed communicating concurrent processes.In order to link DC and TRSL together in a well-founded way, we formally define what it means for a TRSL process to satisfy a DC requirement...... of constraints on the durations of states of the system, i.e. at a high level of abstraction.However, as a state-based logic, it lacks the ability to specifysequential programs and communicating concurrent processes at a concrete level. The Timed RAISE Specification Language (TRSL) [XG99] has this ability.......TRSL is a real-time extension of the RAISE Specification Language (RSL) [Rlg92] which together with its associated method [Rmg95]and tools has shown to be very useful in the industrial development of software systems. Therefore, a promising approach for the development of real-time systemscould be to use DC...

  1. Foundations of DC plasma sources

    Science.gov (United States)

    Tomas Gudmundsson, Jon; Hecimovic, Ante

    2017-12-01

    A typical dc discharge is configured with the negative cathode at one end and a positive anode at the other end, separated by a gas filled gap, placed inside a long glass cylinder. A few hundred volts between the cathode and anode is required to maintain the discharge. The type of discharge that is formed between the two electrodes depends upon the pressure of the working gas, the nature of the working gas, the applied voltage and the geometry of the discharge. We discuss the current–voltage characteristics of the discharge as well as the distinct structure that develops in the glow discharge region. The dc glow discharge appears in the discharge current range from μA to mA at 0.5–300 Pa pressure. We discuss the various phenomena observed in the dc glow discharge, including the cathode region, the positive column, and striations. The dc glow discharge is maintained by the emission of secondary electrons from the cathode target due to the bombardment of ions. For decades, the dc glow discharge has been used as a sputter source. Then it is often operated as an obstructed abnormal glow discharge and the required applied voltage is in the range 2–5 kV. Typically, the cathode target (the material to be deposited) is connected to a negative voltage supply (dc or rf) and the substrate holder faces the target. The relatively high operating pressure, in the range from 2 to 4 Pa, high applied voltages, and the necessity to have a conductive target limit the application of dc glow discharge as a sputter source. In order to lower the discharge voltage and expand the operation pressure range, the lifetime of the electrons in target vicinity is increased through applying magnetic field, by adding permanent magnets behind the cathode target. This arrangement is coined the magnetron sputtering discharge. The various configurations of the magnetron sputtering discharge and its applications are described. Furthermore, the use of dc discharges for chemical analysis, the

  2. Modeling and analysis of fractional order DC-DC converter.

    Science.gov (United States)

    Radwan, Ahmed G; Emira, Ahmed A; AbdelAty, Amr M; Azar, Ahmed Taher

    2017-07-11

    Due to the non-idealities of commercial inductors, the demand for a better model that accurately describe their dynamic response is elevated. So, the fractional order models of Buck, Boost and Buck-Boost DC-DC converters are presented in this paper. The detailed analysis is made for the two most common modes of converter operation: Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM). Closed form time domain expressions are derived for inductor currents, voltage gain, average current, conduction time and power efficiency where the effect of the fractional order inductor is found to be strongly present. For example, the peak inductor current at steady state increases with decreasing the inductor order. Advanced Design Systems (ADS) circuit simulations are used to verify the derived formulas, where the fractional order inductor is simulated using Valsa Constant Phase Element (CPE) approximation and Generalized Impedance Converter (GIC). Different simulation results are introduced with good matching to the theoretical formulas for the three DC-DC converter topologies under different fractional orders. A comprehensive comparison with the recently published literature is presented to show the advantages and disadvantages of each approach. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  3. An Integrated Multifunctional Bidirectional AC/DC and DC/DC Converter for Electric Vehicles Applications

    Directory of Open Access Journals (Sweden)

    Liwen Pan

    2016-06-01

    Full Text Available This paper presents an on-board vehicular battery charger that integrates bidirectional AC/DC converter and DC/DC converter to achieve high power density for application in electric vehicles (EVs. The integrated charger is able to transfer electrical energy between the battery pack and the electric traction system and to function as an AC/DC battery charger. The integrated charger topology is presented and the design of passive components is discussed. The control schemes are developed for motor drive system and battery-charging system with a power pulsation reduction circuit. Simulation results in MATLAB/Simulink and experiments on a 30-kW motor drive and 3.3-kW AC/DC charging prototype validate the performance of the proposed technology. In addition, power losses, efficiency comparison and thermal stress for the integrated charger are illustrated. The results of the analyses show the validity of the advanced integrated charger for electric vehicles.

  4. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    Science.gov (United States)

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  5. The In Vivo Analgesic Activity of Aqueous and Ethanolic Extracts of ...

    African Journals Online (AJOL)

    The purpose of this work is to determine the analgesic activities of Anacardium occidentale and Cymbopogon citratus, plants used in ethnomedicine. Crude aqueous and ethanolic extracts of A. occidentale and C. citratus at the doses of 50 and 100mg/kg body weight were evaluated for analgesic activities in male and ...

  6. DC Microgrids—Part II

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Lu, Xiaonan; Quintero, Juan Carlos Vasquez

    2016-01-01

    . Closely coupled with protection, conflicting grounding objectives, e.g. minimization of stray current and common mode voltage are explained and several practical solutions are presented. Also, standardization efforts for DC systems are addressed. Finally, concluding remarks and important future research...

  7. Electricity-AC versus DC

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 10. Electricity - AC versus DC. D P Sen Gupta. General Article Volume 2 Issue 10 October 1997 pp 46-53. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/10/0046-0053. Author Affiliations.

  8. Voltage Weak DC Distribution Grids

    NARCIS (Netherlands)

    Hailu, T.G.; Mackay, L.J.; Ramirez Elizondo, L.M.; Ferreira, J.A.

    2017-01-01

    This paper describes the behavior of voltage weak DC distribution systems. These systems have relatively small system capacitance. The size of system capacitance, which stores energy, has a considerable effect on the value of fault currents, control complexity, and system reliability. A number of

  9. Laboratory assessment of acaricidal activity of Cymbopogon winterianus, Vitex negundo and Withania somnifera extracts against deltamethrin resistant Hyalomma anatolicum.

    Science.gov (United States)

    Singh, Nirbhay Kumar; Jyoti; Vemu, Bhaskar; Nandi, Abhijit; Singh, Harkirat; Kumar, Rajender; Dumka, V K

    2014-07-01

    Larval packet test was used for detection of resistance levels against cypermethrin and deltamethrin, the most commonly used synthetic pyrethroids, in the multi-host tick Hyalomma anatolicum collected from district Moga, Punjab (India). Results indicated the presence of level I resistance against deltamethrin (RF = 2.81), whereas the tick isolate was susceptible to cypermethrin (RF = 0.2). The aqueous and ethanolic extracts of leaves of Cymbopogon winterianus, Vitex negundo and Withania somnifera along with roots of Vitex negundo were assessed for their acaricidal activity against the larvae of deltamethrin resistant H. anatolicum. The efficacy was assessed by measuring per cent larval mortality and determination of LC50 values. The various ethanolic extracts produced a concentration dependent increase in larval tick mortality, whereas the aqueous extracts exhibited a much lower mortality. The highest mortality (93.7 ± 0.66 %) was observed at the 5.0 % concentration of ethanolic extract of leaves of C. winterianus and the lowest LC50 value (0.011 %) was recorded for ethanolic extracts of leaves of V. negundo. The results indicated that these plant extracts have potential to be developed as herbal acaricides.

  10. Lemongrass (Cymbopogon flexuosus essential oil demonstrated anti-inflammatory effect in pre-inflamed human dermal fibroblasts

    Directory of Open Access Journals (Sweden)

    Xuesheng Han

    2017-06-01

    Full Text Available Lemongrass (Cymbopogon flexuosus essential oil (LEO, which has citral as its main component, has exhibited anti-inflammatory effect in both animal and human cells. In this study, we evaluated the anti-inflammatory activity of a commercially available LEO in pre-inflamed human dermal fibroblasts. We first studied the impact of LEO on 17 protein biomarkers that are critically associated with inflammation and tissue remodeling. LEO significantly inhibited production of the inflammatory biomarkers vascular cell adhesion molecule 1 (VCAM-1, interferon gamma-induced protein 10 (IP-10, interferon-inducible T-cell alpha chemoattractant (I-TAC, and monokine induced by gamma interferon (MIG; decreased levels of the tissue remodeling biomarkers collagen-I and III, epidermal growth factor receptor (EGFR, and plasminogen activator inhibitor (PAI-1; and inhibited the immunomodulatory biomarker macrophage colony-stimulating factor (M-CSF. Furthermore, we studied the impact of LEO on genome-wide gene expression profiles. LEO significantly modulated global gene expression and robustly impacted signaling pathways, many of which are critical for inflammation and tissue remodeling processes. This study provides the first evidence of the anti-inflammatory activity of LEO in human skin cells and indicates that it is a good therapeutic candidate for treating inflammatory conditions of the skin.

  11. Effect of Inhaling Cymbopogon martinii Essential Oil and Geraniol on Serum Biochemistry Parameters and Oxidative Stress in Rats

    Directory of Open Access Journals (Sweden)

    Bruna Fernanda Murbach Teles Andrade

    2014-01-01

    Full Text Available The effects of the inhalation of Cymbopogon martinii essential oil (EO and geraniol on Wistar rats were evaluated for biochemical parameters and hepatic oxidative stress. Wistar rats were divided into three groups n=8: G1 was control group, treated with saline solution; G2 received geraniol; and G3 received C. martinii EO by inhalation during 30 days. No significant differences were observed in glycemia and triacylglycerol levels; G2 and G3 decreased P<0.05 total cholesterol level. There were no differences in serum protein, urea, aspartate aminotransferase activity, and total hepatic protein. Creatinine levels increased in G2 but decreased in G3. Alanine aminotransferase activity and lipid hydroperoxide were higher in G2 than in G3. Catalase and superoxide dismutase activities were higher in G3. C. martinii EO and geraniol increased glutathione peroxidase. Oxidative stress caused by geraniol may have triggered some degree of hepatic toxicity, as verified by the increase in serum creatinine and alanine aminotransferase. Therefore, the beneficial effects of EO on oxidative stress can prevent the toxicity in the liver. This proves possible interactions between geraniol and numerous chemical compounds present in C. martinii EO.

  12. Chemical composition and antimicrobial activity of Cymbopogon nardus citronella essential oil against systemic bacteria of aquatic animals.

    Science.gov (United States)

    Wei, Lee Seong; Wee, Wendy

    2013-06-01

    This paper describes chemical composition and antimicrobial activity of Cymbopogon nardus citronella essential oil against Edwardsiella spp. (n = 21), Vibrio spp. (n = 6), Aeromonas spp. (n = 2), Escherichia coli (n = 2), Salmonella spp. (n = 2), Flavobacterium spp. (n = 1), Pseudomonas spp. (n = 1) and Streptococcus spp. (n = 1) isolated from internal organs of aquatic animals. Due to the ban of antibiotics for aquaculture use, this study was carried out to evaluate the potential of citronella essential oil as alternative to commercial antibiotic use against systemic bacteria in cultured aquatic animals. The essential oil of C. nardus was prepared by using the steam distillation method and the chemical composition of the essential oil was analyzed by gas chromatography-mass spectroscopy (GC-MS). Minimum inhibitory concentration (MIC) of the essential oil tested against bacterial isolates from various aquatic animals and ATCC type strains were determined using two-fold broth micro dilution method with kanamycin and eugenol as positive controls. A total of 22 chemical compounds were detected in C. nardus essential oil with 6-octenal, 3, 7-dimethyl- or citronellal representing the major compounds (29.6%). The MIC values of the citronella oil ranged from 0.244 µg/ml to 0.977 µg/ml when tested against the bacterial isolates. The results of the present study revealed the potential of C. nardus essential oil as alternative to commercial antibiotics for aquaculture use.

  13. Sheppard-Taylor Isolated High Boost DC-DC Converter

    DEFF Research Database (Denmark)

    Chub, Andrii; Siwakoti, Yam Prasad; Vinnikov, Dmitri

    2017-01-01

    be implemented with fewer passive components. Soft-switching in semiconductors allows achieving high efficiency. In addition, the input side current is continuous. The operating principle and the design guidelines derived for the converter are presented. Theoretical results are supported with experimental......This paper presents a new galvanically isolated step-up dc-dc converter intended for low-power but high step-up applications. The proposed converter is capable of regulating output voltage within a wide range of the input voltage or load variations. In contrast to competitors, the converter can...... results obtained using a 100 W prototype. The converter proposed can be used in photovoltaic module level power electronics applications, where a wide input voltage and load regulation range are highly demanded....

  14. A Current-Fed Isolated Bidirectional DC-DC Converter

    DEFF Research Database (Denmark)

    Sun, Xiaofeng; Wu, Xiaoying; Shen, Yanfeng

    2017-01-01

    This paper proposes a current-fed isolated bidirectional DC-DC converter (CF-IBDC) which has the advantages of wide input voltage range, low input current ripple, low conduction losses, and soft switching over the full operating range. Compared with conventional CF-IBDCs, the voltage spikes...... of the low-voltage (LV) side switches in the proposed converter can be eliminated without additional clamp circuits. The converter adopts the pulse width modulation (PWM) plus hybrid phase-shift control scheme such that the bus voltage can match the output voltage by means of the transformer. Thus......, the current stresses and conduction losses of the converter become lower. In addition, the practical ZVS of the secondary-side switches can be realized by adjusting the phase-shift angle within the secondary side when in light load or no load condition. The operating principles and characteristics including...

  15. Dilation and Curettage (D&C)

    Science.gov (United States)

    ... For Patients About ACOG Dilation and Curettage (D&C) Home For Patients Search FAQs Dilation and Curettage ( ... February 2016 PDF Format Dilation and Curettage (D&C) Special Procedures What is dilation and curettage (D& ...

  16. NAMMA DC-8 DROPSONDE V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NAMMA DC-8 Dropsonde dataset were collected by the DC-8 dropsonde system, which uses an integrated, highly accurate, GPS-located atmospheric profiling dropsonde...

  17. Implementation of hierarchical control in DC microgrids

    DEFF Research Database (Denmark)

    Jin, Chi; Wang, Peng; Xiao, Jianfang

    2014-01-01

    DC microgrids are becoming popular in low-voltage distribution systems due to the better compatibility with photovoltaic panels, electric vehicles, and dc loads. This paper presents a practical dc microgrid developed in the Water and Energy Research Laboratory (WERL) in the Nanyang University of ...

  18. Toward the Universal DC Distribution System

    NARCIS (Netherlands)

    Mackay, L.J.; van der Blij, N.H.; Ramirez Elizondo, L.M.; Bauer, P.

    2017-01-01

    AbstractDue to an increasing number of power generation units and load devices operating with direct current (DC) at distribution level, there is a potential benefit of leading efforts toward building a DC distribution system. However, the implementation of DC distribution systems faces important

  19. Hierarchical Power Sharing Control in DC Microgrids

    DEFF Research Database (Denmark)

    Peyghami, Saeed; Mokhtari, Hossein; Blaabjerg, Frede

    2016-01-01

    Because of the advances in power electronics, DC-based power systems, have been used in industrial applications such as data centers [18], space applications [10], aircraft [12], offshore wind farms, electric vehicles [56], DC home systems [5, 20], and high-voltage DC transmission systems...

  20. Cytotoxic and genotoxic effects of aqueous extracts of five medicinal plants on Allium cepa Linn.

    Science.gov (United States)

    Akinboro, A; Bakare, A A

    2007-07-25

    The cytotoxic and genotoxic effects of aqueous extracts of five medicinal plants: Azadirachta indica (A. Juss), Morinda lucida (Benth.), Cymbopogon citratus (DC Stapf.), Mangifera indica (Linn.) and Carica papaya (Linn.) was evaluated using the Allium cepa assay. The extracts were prepared with tap water as practised locally. Onion bulbs were exposed to 1, 5, 10, 25 and 50%; and 1, 2.5, 5, 10 and 20% concentrations (v/v) of each of the extracts for macroscopic and microscopic analyses, respectively. There was concentration-dependent and statistically significant (P<0.05) inhibition of root growth by the extracts when compared with the control. The EC(50) obtained for decoctions of Azadirachta indica. Cymbopogon citratus, Mangifera indica and Carica papaya were 0.6, 3.0, 1.4 and 0.8%, respectively. It was 2.6 and 0.8% for the squeezed extracts of Azadirachta indica and Morinda lucida, respectively. All the tested extracts were observed to have mitodepressive effects on cell division and induced mitotic spindle disturbance in Allium cepa. These results suggest an inhibitory, mitodepressive and turbagenic activities of the aqueous extracts on Allium cepa.

  1. High efficiency high step-up DC/DC converters - a review

    National Research Council Canada - National Science Library

    Tomaszuk, A; Krupa, A

    2011-01-01

    .... This review is focused on high efficiency step-up DC/DC converters with high voltage gain. The differentiation is based on the presence or lack of galvanic isolation. A comparison and discussion of different DC/DC step-up topologies will be performed across number of parameters and presented in this paper.

  2. High Power Zero-Voltage and Zero-Current Switching DC-DC Converters

    Directory of Open Access Journals (Sweden)

    Jaroslav Dudrik

    2005-01-01

    Full Text Available The paper presents principles and properties of the soft switching PWM DC-DC converters. The attention is focused mainly on high power applications and thus the full-bridge inverters are used in DC-DC converters. Considerations are also given to the control methods and principles of the switching and conduction losses reduction.

  3. A Family of Four Quadrant DC/DC Converters with Reduced Number of Components

    DEFF Research Database (Denmark)

    Mostaan, Ali; Soltani, Mohsen

    2015-01-01

    A family of four quadrant DC/DC converters is presented in this paper. Compare with existing four quadrant DC/DC converters that have been introduced in literature, the proposed converters have lower number of components. There are two bidirectional switches, two coupled inductors and one capacitor...

  4. Óleos essenciais de Cymbopogon nardus, Cinnamomum zeylanicum e Zingiber officinale: composição, atividades antioxidante e antibacteriana Essential oils of Cinnamomum zeylanicum, Cymbopogon nardus and Zingiber officinale: composition, antioxidant and antibacterial activities

    Directory of Open Access Journals (Sweden)

    Milene Aparecida Andrade

    2012-06-01

    Full Text Available Objetivou-se neste estudo caracterizar quimicamente e avaliar as atividades antioxidante e antibacteriana dos óleos essenciais de citronela (Cymbopogon nardus, canela (Cinnamomum zeylanicum e gengibre (Zingiber officinale. A obtenção do óleo essencial foi realizada utilizando a técnica de hidrodestilação por meio do aparelho de Clevenger modificado e a identificação e quantificação dos constituintes pelas análises em CG/EM e CG-DIC. A avaliação da atividade antibacteriana foi realizada por meio da técnica difusão cavidade em ágar, utilizando os microrganismos Staphylococcus aureus ATCC 6538, Listeria monocytogenes ATCC 19117, Escherichia coli ATCC 11229, Salmonella Cholerasuis ATCC 6539 e Pseudomonas aeruginosa ATCC 15442. A atividade antioxidante foi avaliada utilizando sistema β-caroteno/ácido linoléico e o método de seqüestro de radicais DPPH. Nas análises cromatográficas, os constituintes majoritários encontrados no óleo essencial de C. nardus foram citronelal (47,12%, geraniol (18,56% e citronelol (11,07%, no óleo essencial de C. zeylanicum foram identificados (E- cinamaldeído (77,72%, acetato de (E-cinamila (5,99% e o monoterpenóide 1,8-cineol (4,66% e, para Z. officinale os majoritários foram geranial (25,06%, neral (16,47%, 1,8-cineol (10,98%, geraniol (8,51%, acetato de geranila (4,19% e o canfeno (4,30%. Os óleos essenciais apresentaram atividade antibacteriana tanto para bactérias Gram-negativas como para bactérias Gram-positivas, sendo que o óleo essencial de C. zeylanicum foi o mais eficiente. A atividade antioxidante foi evidenciada pelo teste β-caroteno/ácido linoléico, respectivamente, para C. nardus, seguido de Z. officinale e C. zeylanicum, e pelo teste do DPPH foi observada apenas para C. nardus.The aims of this study were to chemically characterize and to evaluate the antioxidant and antibacterial activities of the citronella (Cymbopogon nardus, cinnamon (Cinnamomum zeylanicum and ginger

  5. 75 FR 36579 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-30, DC-10-30F, DC-10-30F (KC...

    Science.gov (United States)

    2010-06-28

    ... Corporation Model DC- 10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, and MD-10-30F...). SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain Model DC-10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC- 10-40, DC10-40F, and MD-10-30F airplanes. This proposed AD would...

  6. 75 FR 61352 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-30, DC-10-30F, DC-10-30F (KC...

    Science.gov (United States)

    2010-10-05

    ... Corporation Model DC- 10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, and MD-10-30F... new airworthiness directive (AD) for certain Model DC-10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC- 10-40F, and MD-10-30F airplanes. This AD requires doing a one-time inspection of the...

  7. A Feed-Forward Control Realizing Fast Response for Three-Branch Interleaved DC-DC Converter in DC Microgrid

    DEFF Research Database (Denmark)

    Wang, Haojie; Han, Minxiao; Yan, Wenli

    2016-01-01

    changing. A prototype of the TIDC is developed and an experimental platform is built. The experiment results show that DC bus voltage sags or swells caused by load changing can be reduced and the time for voltage recovery can be decreased significantly with the proposed feed-forward control.......It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC) is proposed...... for storage batteries in DC microgrids. The working principle of TIDC is analyzed, and the factors influencing the response rate based on the dual-loop constant voltage control for TIDC are discussed, and then the method of feed-forward control for TIDC is studied to improve the response rate for load...

  8. A Feed-Forward Control Realizing Fast Response for Three-Branch Interleaved DC-DC Converter in DC Microgrid

    Directory of Open Access Journals (Sweden)

    Haojie Wang

    2016-07-01

    Full Text Available It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC is proposed for storage batteries in DC microgrids. The working principle of TIDC is analyzed, and the factors influencing the response rate based on the dual-loop constant voltage control for TIDC are discussed, and then the method of feed-forward control for TIDC is studied to improve the response rate for load changing. A prototype of the TIDC is developed and an experimental platform is built. The experiment results show that DC bus voltage sags or swells caused by load changing can be reduced and the time for voltage recovery can be decreased significantly with the proposed feed-forward control.

  9. FLYWHEEL AND A DC MACHINE

    Directory of Open Access Journals (Sweden)

    IVAN ALCALÁ

    2014-01-01

    Full Text Available Este artículo describe el análisis, modelado y simulación de un vehículo eléctrico (EV enfocado al desarrollo de un banco de pruebas para reproducir la dinámica del EV. El banco está formado por un drive de motor de inducción (IM acoplado directamente a una máquina de DC y a un volante de inercia a través de una transmisión. El volante de inercia y la máquina de DC reproducen la dinámica y las fuerzas que actúan en el vehículo. Se propone una metodología para diseñar un banco de pruebas de EV para estudiar el comportamiento de vehículos eléctricos cercano a las condiciones de operación reales. El análisis de las fuerzas en el EV en conjunto con la máquina DC define las condiciones de operación del EV. El modelado y la simulación son desarrollados en MATLAB/Simulink, el banco de pruebas implementado es controlado por un DSP. Finalmente, los resultados de simulación y experimentales obtenidos validan el funcionamiento del banco de prueba.

  10. Active DC Bus Signaling Control Method for Coordinating Multiple Energy Storage Devices in DC Microgrid

    OpenAIRE

    Li, Fulong; Lin, Zhengyu; Qian, Zhongnan; Wu, Jiande

    2017-01-01

    This paper will be presented in 2017 Second IEEE International Conference on DC Microgrids (ICDCM) on 28th June 2017. Abstract: Management of multiple energy storage devices in a DC microgrid is a challenge. Conventional method, such as droop control, cannot ensure accurate current sharing in coordinating multiple battery banks, which limits the DC microgrid system performance. This paper proposed an active DC bus signaling (ADBS) method to coordinate multiple battery banks in a DC microg...

  11. Chemical composition, antioxidant and antimicrobial activity of the essential oil and methanol extract of the Egyptian lemongrass Cymbopogon proximus Stapf

    Directory of Open Access Journals (Sweden)

    Selim, Samy A.

    2011-03-01

    Full Text Available The present study was conducted to evaluate the in vitro antimicrobial and antioxidant properties of the essential oil (Eo and methanol extract from a unique, Egyptian endemic plant, Cymbopogon proximus STAPF. The chemical composition of a hydrodistilled Eo of C. proximus was analyzed by a GC and GC/MS system. A total of 19 constituents representing 95.47% of the oil were identified: piperitone (72.44%, elemol (9.43%, α - eudesmol (4.34%, limonene (2.45% and β- eudesmol (1.26% were the main components comprising 88.92% of the oil. The antimicrobial test results showed that the Eo of C. proximus strongly inhibited the growth of the test bacteria studied, except for yeast species while the methanol extract had moderate antibacterial, but no anti-candida activity. Bacillus cereus and Salmonella choleraesuis were proven to be the most susceptible against Eo. The exposure time of Eo for complete inhibition of cell viability of B. cereus and S. choleraesuis were found to be 5 % at 10 min and 1% at 10 min, respectively. The antioxidative potential of the samples was evaluated using methods of inhibition of the free radical 2,2-diphenyl-1- picrylhydrazyl (DPPH system. The methanol extract was able to reduce the stable free radical DPPH with an IC50 of 48.66±3.1 μg/ml. The results presented here may suggest that the Eo and extracts of C. proximus possess antimicrobial and antioxidant properties, and therefore, can be used as natural preservative ingredients in food and/or pharmaceuticals.El presente estudio fue llevado a cabo para evaluar las propiedades antioxidantes y antimicrobianas in vitro del aceite esencial (Eo y extractos de metanol de una genuina y endémica planta egipcia, Cymbopogon proximus Stapf. La composición química de un hidrodestilado Eo de C. proximus fue analizado por GC y GC/MS. Un total de 19 constituyentes representando el 95.47% del aceite fueron identificados; piperitona (72.44%, elemol (9.43%, α-eudesmol (4.34%, limoneno

  12. Effects of Cymbopogon winterianus Jowitt ex Bor essential oil on the growth and morphogenesis of Trichophyton mentagrophytes

    Directory of Open Access Journals (Sweden)

    Fillipe de Oliveira Pereira

    2011-03-01

    Full Text Available Trichophyton mentagrophytes is a fungus causative agent of dermatophytosis, affecting humans worldwide. This has driven the search for products for the treatment of these infections. Accordingly, the aim of this study was to investigate the antifungal activity of the Cymbopogon winterianus essential oil against T. mentagrophytes. The antifungal tests consisted of antifungal screening, determination of MIC and MFC, analysis of the essential oil's effects on mycelial growth, germination of fungal spores, fungal viability, morphogenesis, cell wall (test with sorbitol and cell membrane (cell leakage test of T. mentagrophytes. Upon screening, the oil inhibited all strains, with zones of growth inhibition of 24-28 mm in diameter. The MIC was 312 μg/mL and CFM was 2500 μg/mL for almost all the strains tested. There were morphological changes in the conidia group, form and pigmentation of hyphae. The antifungal action of the product does not involve the cell wall and its action may involve the fungal plasma membrane. It is concluded that C. winterianus essential oil constitutes a potential antifungal product, especially for the treatment of dermatophytosis.Trichophyton mentagrophytes é um fungo causador de dermatofitoses, afetando humanos em todo o mundo. Isto direciona a busca de produtos para o tratamento destas infecções. Assim, este estudo teve por objetivo investigar a atividade antifúngica do óleo essencial de Cymbopogon winterianus contra T. mentagrophytes. Os ensaios antifúngicos foram constituídos do screening antifúngico, da determinação CIM e CFM, da análise dos efeitos do óleo essencial no crescimento micelial, na germinação dos esporos, na viabilidade fúngica, na morfogênese, na parede celular (ensaio com sorbitol e na membrana celular (ensaio de lise celular de T. mentagrophytes. No screening, o óleo inibiu todas as cepas, com zonas de inibição de crescimento de 24-28 mm de diâmetro. A CIM foi de 312 μg/mL e a CFM

  13. Effect of Cymbopogon martinii, Foeniculum vulgare, and Trachyspermum ammi Essential Oils on the Growth and Mycotoxins Production by Aspergillus Species

    Directory of Open Access Journals (Sweden)

    Negero Gemeda

    2014-01-01

    Full Text Available This study was performed to investigate effect of essential oils on Aspergillus spore germination, growth, and mycotoxin production. In vitro antifungal and antiaflatoxigenic activities of Cymbopogon martinii, Foeniculum vulgare, and Trachyspermum ammi essential oils were carried out on toxigenic strains of Aspergillus species. Plant materials were hydrodistilled for 4-5 h in Clevenger apparatus. 0.25 μL/mL, 0.5 μL/mL, 1 μL/mL, 2 μL/mL, and 4 μL/mL concentrations of each essential oil were prepared in 0.1% Tween 80 (V/V. T. ammi oil showed highest antifungal activity. Absolute mycelial inhibition was recorded at 1 μL/mL by essential oils of T. ammi. The oil also showed complete inhibition of spore germination at a concentration of 2 μL/mL. In addition, T. ammi oil showed significant antiaflatoxigenic potency by totally inhibiting toxin production from A. niger and A. flavus at 0.5 and 0.75 μL/mL, respectively. C. martinii, F. vulgare, and T. ammi oils as antifungals were found superior over synthetic preservative. Moreover, a concentration of 5336.297 μL/kg body weight was recorded for LC50 on mice indicating the low mammalian toxicity. In conclusion, the essential oils from T. ammi can be a potential source of safe natural food preservative for food commodities contamination by Aspergillus species.

  14. Efeito do óleo de capim limão (Cymbopogon flexuosus Stapf no controle do carrapato dos bovinos

    Directory of Open Access Journals (Sweden)

    C.A. Agnolin

    2014-03-01

    Full Text Available Esta pesquisa foi conduzida com o objetivo de avaliar o efeito in vitro e in vivo do óleo essencial de capim limão (Cymbopogon flexuosus Stapf sobre o carrapato dos bovinos [Rhipicephalus (Boophilus microplus]. Na experimentação in vitro foi utilizado o grupo controle negativo e oito concentrações do óleo de capim-limão (0,5; 1; 2; 5; 10; 20; 50; 100%, em fêmeas ingurgitadas do carrapato. A eficácia de controle foi de 0; 20; 39; 99,5; 100; 100; 100; 100 e 100%, respectivamente. Para a experimentação in vivo foram constituídos três grupos (controle negativo, óleo de capim limão a 2,0% - nível estimado mediante análise de regressão, correspondendo a 95% de eficácia de controle do carrapato da pesquisa in vitro e amitraz a 0,025%, com dezoito vacas da raça Holandesa. Antes (média dos dias -3, -2, -1 e após a aplicação do produto (1, 2, 3, 5, 7, 10, 14 e 21 dias, foram contadas fêmeas ingurgitadas do carrapato. A eficácia de controle foi de 0; 54 e 74,5%, respectivamente, 21dias após o tratamento. Após a aplicação dos tratamentos (controle negativo x tratamento fitoterápico, foram avaliadas as variáveis fisiológicas: frequência cardíaca, respiratória, temperatura do globo ocular e temperatura da pele; os resultados foram similares entre os tratamentos.

  15. Growth inhibition and morphological alterations of Trichophyton rubrum induced by essential oil from Cymbopogon winterianus Jowitt ex Bor

    Directory of Open Access Journals (Sweden)

    Fillipe de Oliveira Pereira

    2011-03-01

    Full Text Available Trichophyton rubrum is one of the most common fungi causer of dermatophytosis, mycosis that affect humans and animals around the world. Researches aiming new products with antifungal activity become necessary to overcome difficulties on treatment of these infections. Accordingly, this study aimed to investigate the antifungal activity of essential oil from Cymbopogon winterianus against the dermatophyte T. rubrum. The antifungal screening was performed by solid medium diffusion method with 16 T. rubrum strains, minimum inhibitory concentration (MIC and minimum fungicide concentration (MFC were determined using the microdilution method. The effects on mycelial dry weight and morphology were also observed. Screening showed essential oil in natura inhibited all the tested strains, with inhibition zones between 24-28 mm diameter. MIC50 and MIC90 values of the essential oil were 312 µg/mL for nearly all the essayed strains (93.75 % while the MFC50 and MFC90 values were about eight times higher than MIC for all tested strains. All tested essential oil concentrations managed to inhibit strongly the mycelium development. Main morphological changes on the fungal strains observed under light microscopy, which were provided by the essential oil include loss of conidiation, alterations concerning form and pigmentation of hyphae. In the oil presence, colonies showed folds, cream color and slightly darker than the control, pigment production was absent on the reverse and with evident folds. It is concluded that C. winterianus essential oil showed activity against T. rubrum. Therefore, it could be known as potential antifungal compound especially for protection against dermatophytosis.

  16. Growth Inhibition and Morphological Alterations of Trichophyton Rubrum Induced by Essential oil from Cymbopogon Winterianus Jowitt Ex Bor

    Science.gov (United States)

    de Oliveira Pereira, Fillipe; Alves Wanderley, Paulo; Cavalcanti Viana, Fernando Antônio; Baltazar de Lima, Rita; Barbosa de Sousa, Frederico; de Oliveira Lima, Edeltrudes

    2011-01-01

    Trichophyton rubrum is one of the most common fungi causer of dermatophytosis, mycosis that affect humans and animals around the world. Researches aiming new products with antifungal activity become necessary to overcome difficulties on treatment of these infections. Accordingly, this study aimed to investigate the antifungal activity of essential oil from Cymbopogon winterianus against the dermatophyte T. rubrum. The antifungal screening was performed by solid medium diffusion method with 16 T. rubrum strains, minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined using the microdilution method. The effects on mycelial dry weight and morphology were also observed. Screening showed essential oil in natura inhibited all the tested strains, with inhibition zones between 24-28 mm diameter. MIC50 and MIC90 values of the essential oil were 312 μg/mL for nearly all the essayed strains (93.75 %) while the MFC50 and MFC90 values were about eight times higher than MIC for all tested strains. All tested essential oil concentrations managed to inhibit strongly the mycelium development. Main morphological changes on the fungal strains observed under light microscopy, which were provided by the essential oil include loss of conidiation, alterations concerning form and pigmentation of hyphae. In the oil presence, colonies showed folds, cream color and slightly darker than the control, pigment production was absent on the reverse and with evident folds. It is concluded that C. winterianus essential oil showed activity against T. rubrum. Therefore, it could be known as potential antifungal compound especially for protection against dermatophytosis. PMID:24031626

  17. A Feedback Passivation Design for DC Microgrid and Its DC/DC Converters

    Directory of Open Access Journals (Sweden)

    Feifan Ji

    2016-12-01

    Full Text Available There are difficulties in analyzing the stability of microgrids since they are located on various network structures. However, considering that the network often consists of passive elements, the passivity theory is applied in this paper to solve the above-mentioned problem. It has been formerly shown that when the network is weakly strictly positive real (WSPR, the DC microgrid is stable if all interfaces between the microgrid and converters are made to be passive, which is called interface passivity. Then, the feedback passivation method is proposed for the controller design of various DC–DC converters to achieve the interface passivity. The interface passivity is different from the passivity of closed-loop systems on which the passivity based control (PBC concentrates. The feedback passivation design is detailed for typical buck converters and boost converters in terms of conditions that the controller parameters should satisfy. The theoretical results are verified by a hardware-in-loop real-time labotray (RTLab simulation of a DC microgrid with four generators.

  18. DC Voltage Droop Control Implementation in the AC/DC Power Flow Algorithm: Combinational Approach

    DEFF Research Database (Denmark)

    Akhter, F.; Macpherson, D.E.; Harrison, G.P.

    2015-01-01

    In this paper, a combinational AC/DC power flow approach is proposed for the solution of the combined AC/DC network. The unified power flow approach is extended to include DC voltage droop control. In the VSC based MTDC grids, DC droop control is regarded as more advantageous in terms...... of operational flexibility, as more than one VSC station controls the DC link voltage of the MTDC system. This model enables the study of the effects of DC droop control on the power flows of the combined AC/DC system for steady state studies after VSC station outages or transient conditions without needing...... to use its complete dynamic model. Further, the proposed approach can be extended to include multiple AC and DC grids for combined AC/DC power flow analysis. The algorithm is implemented by modifying the MATPOWER based MATACDC program and the results shows that the algorithm works efficiently....

  19. Using PBL to Improve Educational Outcomes and Student Satisfaction in the Teaching of DC/DC and DC/AC Converters

    Science.gov (United States)

    Martinez-Rodrigo, Fernando; Herrero-De Lucas, Luis Carlos; de Pablo, Santiago; Rey-Boue, Alexis B.

    2017-01-01

    This paper examines the question of how to use project-based learning to increase student performance and satisfaction in a power electronics course addressing the topics of dc/dc and dc/ac converters, the assembly of a dc/dc converter, and the use of a commercial speed drive. A detailed presentation of the methodology is shown, and the results…

  20. Elimination of output voltage oscillations in DC-DC converter using PWM with PI controller

    Directory of Open Access Journals (Sweden)

    Sreenivasappa Veeranna Bhupasandra

    2010-01-01

    Full Text Available In this paper the SIMULINK model of a PWM controlled DC-DC converter is modeled using switching function concept to control the speed of the DC motor. The presence of the voltage oscillation cycles due to higher switching frequency in the DC-DC converter is identified. The effect of these oscillations on the output voltage of the converter, Armature current, Developed torque and Speed of the DC motor is analyzed. In order to minimize the oscillation cycles the PI controller is proposed in the PWM controller.

  1. Block clustering based on difference of convex functions (DC) programming and DC algorithms.

    Science.gov (United States)

    Le, Hoai Minh; Le Thi, Hoai An; Dinh, Tao Pham; Huynh, Van Ngai

    2013-10-01

    We investigate difference of convex functions (DC) programming and the DC algorithm (DCA) to solve the block clustering problem in the continuous framework, which traditionally requires solving a hard combinatorial optimization problem. DC reformulation techniques and exact penalty in DC programming are developed to build an appropriate equivalent DC program of the block clustering problem. They lead to an elegant and explicit DCA scheme for the resulting DC program. Computational experiments show the robustness and efficiency of the proposed algorithm and its superiority over standard algorithms such as two-mode K-means, two-mode fuzzy clustering, and block classification EM.

  2. Chaos analysis and chaotic EMI suppression of DC-DC converters

    CERN Document Server

    Zhang, Bo

    2014-01-01

    Introduces chaos theory, its analytical methods and the means to apply chaos to the switching power supply design DC-DC converters are typical switching systems which have plenty of nonlinear behaviors, such as bifurcation and chaos. The nonlinear behaviors of DC-DC converters have been studied heavily over the past 20 years, yet researchers are still unsure of the practical application of bifurcations and chaos in switching converters. The electromagnetic interference (EMI), which resulted from the high rates of changes of voltage and current, has become a major design criterion in DC-DC co

  3. High gain high efficiency resonant DC-DC converter

    Science.gov (United States)

    Shang, Fei

    Low voltage power sources have played an important role in applications such as automotive system, renewable energy power generation and so on, where require a high gain DC-DC step-up converter. The converter is going to sustain a very high input current which can bring many design challenges in the existing topologies, such as high component current stress and power loss, complex and costly design for magnetic components, high input current ripple, etc. A new topology of high gain DCDC step-up converter proposed in this dissertation. The topology has many merits such as high gain capability, high efficiency, low components stress and requirement of the transformer, simple topology with less number of active switching devices, and easy to control. The dissertation carries out theoretical analysis of the proposed topology under different operating modes and the voltage gain has been deduced for each mode. The design of circuit components has been well studied, including the power devices current stress and power, the selection of transformer turns-ratio, the design method of the resonant tank and input current ripple. System dynamic state-space models are acquired by using generalized averaging method. Small signal model of the converter is achieved by linearization of the dynamic model around the operating points. The stability study indicates that the open loop system is stable at all operating points, except some operating points containing RHP zeros which can cause closed loop system unstable. The parameter sensitivity study shows that the system transfer function is not greatly affected by the variation of the leakage inductance and load resistance. A design of PI controller is implemented to achieve the output voltage regulation. Simulations have been carried out to validate the circuit operation and support the design analysis. A 2kW prototype has been built for experimental testing. The experimental results are in a good agreement with the theoretical

  4. Two new families of high-gain dc-dc power electronic converters for dc-microgrids

    Science.gov (United States)

    Prabhala, Venkata Anand Kishore

    Distributing the electric power in dc form is an appealing solution in many applications such as telecommunications, data centers, commercial buildings, and microgrids. A high gain dc-dc power electronic converter can be used to individually link low-voltage elements such as solar panels, fuel cells, and batteries to the dc voltage bus which is usually 400 volts. This way, it is not required to put such elements in a series string to build up their voltages. Consequently, each element can function at it optimal operating point regardless of the other elements in the system. In this dissertation, first a comparative study of dc microgrid architectures and their advantages over their ac counterparts is presented. Voltage level selection of dc distribution systems is discussed from the cost, reliability, efficiency, and safety standpoints. Next, a new family of non-isolated high-voltage-gain dc-dc power electronic converters with unidirectional power flow is introduced. This family of converters benefits from a low voltage stress across its switches. The proposed topologies are versatile as they can be utilized as single-input or double-input power converters. In either case, they draw continuous currents from their sources. Lastly, a bidirectional high-voltage-gain dc-dc power electronic converter is proposed. This converter is comprised of a bidirectional boost converter which feeds a switched-capacitor architecture. The switched-capacitor stage suggested here has several advantages over the existing approaches. For example, it benefits from a higher voltage gain while it uses less number of capacitors. The proposed converters are highly efficient and modular. The operating modes, dc voltage gain, and design procedure for each converter are discussed in details. Hardware prototypes have been developed in the lab. The results obtained from the hardware agree with those of the simulation models.

  5. Simultaneous distribution of AC and DC power

    Science.gov (United States)

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  6. Teaching about operation of brushless DC motors

    OpenAIRE

    Čufar, Aleksandra

    2013-01-01

    Brush DC motor is being replaced by brushless DC motors on every area of application. My diploma thesis is a presentation of brushless DC motor, how it works and its application. Within first part we describe various electric motors and their application. There are several types of electric motors division. Last to be added is a brushless motor. Within second part of thesis we look into a brushless DC motor, how it works, its application and control. In the third part of thesis we construct a...

  7. Drilling history core hole DC-8

    Energy Technology Data Exchange (ETDEWEB)

    1978-10-01

    Core hole DC-8 was completed in August, 1978 by Boyles Brothers Drilling Company, Spokane, Washington, under subcontract to Fenix and Scission, Inc. The hole was cored for the US Department of Energy and the Rockwell Hanford Operations' Basalt Waste Isolation Program. Fenix and Scisson, Inc. furnished the engineering, daily supervision of the core drilling activities, and geologic core logging for hole DC-8. Core hole DC-8 is located on the Hanford Site near the Wye Barricade and 50 feet northwest of rotary hole DC-7. The Hanford Site vation coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 mean sea level. The purpose of core hole DC-8 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection, and to provide a borehole for hydrologic testing and cross-hole seismic shear and pressure wave velocity studies with rotary hole DC-7. The total depth of core hole DC-8 was 4100.5 feet. Core recovery exceeded 97 percent of the total footage cored.

  8. A Survey on Voltage Boosting Techniques for Step-Up DC-DC Converters

    DEFF Research Database (Denmark)

    Forouzesh, Mojtaba; Siwakoti, Yam Prasad; Gorji, Saman Asghari

    2016-01-01

    Step-up dc-dc converters are used to boost the voltage level of the input to a higher output level. Despite of its features such as simplicity of implementation, the fundamental boost dc-dc converter has shortcomings such as low boost ability and low power density. With these limitations, researc......Step-up dc-dc converters are used to boost the voltage level of the input to a higher output level. Despite of its features such as simplicity of implementation, the fundamental boost dc-dc converter has shortcomings such as low boost ability and low power density. With these limitations......, researches on new voltage boosting techniques are inevitable for various power converter applications. This can be achieved either by additional magnetic or by electric field storage elements with switching elements (switch and/or diode) in different configurations. Such combination of primary voltage...

  9. Digitally intensive DC-DC converter for extreme space environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Space Micro –Arizona State University (ASU) team will develop an all-digitally controlled, wide temperature range point-of-load switch-mode DC-DC regulator...

  10. Ultra-high Efficiency DC-DC Converter using GaN Devices

    DEFF Research Database (Denmark)

    Ramachandran, Rakesh

    2016-01-01

    with the PCB layout and the magnetics. This thesis mainly covers the design and implementation of various high efficiency isolated dcdc converters in the range of 1 to 2.5 kW of output power. Both hard-switched and soft-switched topologies in isolated dc-dc converters has been studied and realized......The demands for high efficiency dc-dc power converters are increasing day by day in various applications such as telecommunication, data-centers, electric vehicles and various renewable energy systems. Silicon (Si) has been used as the semiconductor material in majority of the power devices...... properties of GaN devices can be utilized in power converters to make them more compact and highly efficient. This thesis entitled “Ultra-high Efficiency DC-DC Converter using GaN devices” focuses on achieving ultra-high conversion efficiency in an isolated dc-dc converter by the optimal utilization of Ga...

  11. Digitally intensive DC-DC converter for extreme space environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Space Micro-Arizona State University (ASU) team will develop an all-digitally controlled, wide temperature range point-of-load switch-mode DC-DC regulator core...

  12. Real-Time Implementation of a Fuzzy Logic Controller for DC-DC Switching Converters

    National Research Council Canada - National Science Library

    Rubaai, Ahmed

    2005-01-01

    This report presents a successful implementation of a fuzzy logic controller structure for dc-dc switching converters and evaluates experimentally its sensitivity for variable supply voltages and load...

  13. Wide Temperature Range DC-DC Boost Converters for Command/Control/Drive Electronics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We shall develop wide temperature range DC-DC boost converters that can be fabricated using commercial CMOS foundries. The boost converters will increase the low...

  14. Development of a DC-DC conversion powering scheme for the CMS Phase-1 pixel upgrade

    CERN Document Server

    Feld, Lutz Werner; Karpinski, Waclaw; Klein, Katja; Lipinski, Martin; Preuten, Marius; Max Rauch; Rittich, David Michael; Sammet, Jan Domenik; Wlochal, Michael

    2014-01-01

    A novel powering scheme based on the DC-DC conversion technique will be exploited to power the CMS Phase-1 pixel detector. DC-DC buck converters for the CMS pixel project have been developed, based on the AMIS5 ASIC designed by CERN. The powering system of the Phase-1 pixel detector is described and the performance of the converter prototypes is detailed, including power efficiency, stability of the output voltage, shielding, and thermal management. Results from a test of the magnetic field tolerance of the DC-DC converters are reported. System tests with pixel modules using many components of the future pixel barrel system are summarized. Finally first impressions from a pre-series of 200 DC-DC converters are presented.

  15. Decentralized Nonlinear Controller Based SiC Parallel DC-DC Converter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is aimed at demonstrating the feasibility of a Decentralized Control based SiC Parallel DC-DC Converter Unit (DDCU) with targeted application for...

  16. Modular Power System Configured with Standard Product Hybrid DC-DC Converters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — VPT proposes an innovative concept whereby complex NASA space power electronic systems can be configured using a small number of qualified hybrid DC-DC converter and...

  17. DIAGNOSTIC/PROGNOSTIC EXPERIMENTS FOR CAPACITOR DEGRADATION AND HEALTH MONITORING IN DC-DC CONVERTERS

    Data.gov (United States)

    National Aeronautics and Space Administration — Studying and analyzing the ageing mechanisms of electronic components avionics in systems such as the GPS and INAV are of critical importance. In DC-DC power...

  18. Improved Control Strategy for T-type Isolated DC/DC Converters

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Wang, Yanbo

    2017-01-01

    . Under the proposed strategy, the primary circulating current flows through the auxiliary switches (metal–oxide–semiconductor field-effect transistors) instead of their body diodes in free-wheeling periods. Such feature can reduce conduction losses, thereby improving the efficiency of T-type isolated DC......T-type isolated DC/DC converters have recently attracted attention due to their numerous advantages, including few components, low cost, and symmetrical operation of transformers. This study proposes an improved control strategy for increasing the efficiency of T-type isolated DC/DC converters....../DC converters. The operation principles and performances of T-type isolated DC/DC converters under the proposed control strategy are analyzed in detail and verified through the simulation and experimental results....

  19. Acaricidal activity of Cymbopogon winterianus, Vitex negundo and Withania somnifera against synthetic pyrethroid resistant Rhipicephalus (Boophilus) microplus.

    Science.gov (United States)

    Singh, Nirbhay Kumar; Jyoti; Vemu, Bhaskar; Nandi, Abhijit; Singh, Harkirat; Kumar, Rajender; Dumka, V K

    2014-01-01

    Detection of resistance levels against cypermethrin and deltamethrin, the most commonly used synthetic pyrethroids (SPs) against Rhipicephalus (Boophilus) microplus collected from Moga, Punjab (India) was carried out using larval packet test. Results indicated the presence of resistance of level I and III against cypermethrin (resistance factors (RF) = 4.67) and deltamethrin (RF = 34.2), respectively. Adult immersion test was used to assess the acaricidal activity of aqueous and ethanolic extracts of leaves of Cymbopogon winterianus, Vitex negundo, and Withania somnifera along with roots of V. negundo against the SP resistant engorged females of R. (B.) microplus. The efficacy of various extracts was assessed by estimation of percent adult mortality, reproductive index (RI), percent inhibition of oviposition (%IO), and hatching rate. A concentration dependent increase in tick mortality was recorded which was more marked with various ethanolic extracts, and highest mortality was recorded in ticks treated with ethanolic extract of leaves of C. winterianus. The LC50 values were determined by applying regression equation analysis to the probit transformed data of mortality for various aqueous and ethanolic extracts. Acaricidal property was recorded to be higher in ethanolic extracts, and high activity was found with the ethanolic extract of leaves of C. winterianus with LC50 (95% CL) values of 0.46% (0.35-0.59%), followed by W. somnifera as 5.21% (4.45-6.09%) and V. negundo as 7.02% (4.58-10.74%). The egg mass weight of the live ticks treated with different concentrations of the various extract was significantly (p < 0.01) lower than that of control ticks; consequently, the RI and the %IO value of the treated ticks were reduced. Further, complete inhibition of hatching was recorded in eggs laid by ticks treated with ethanolic extracts of leaves of V. negundo and aqueous extracts of leaves of W. somnifera. The results of the current study indicate that extracts of C

  20. Chemical Composition and Anti-Candidiasis Mediated Wound Healing Property of Cymbopogon nardus Essential Oil on Chronic Diabetic Wounds.

    Science.gov (United States)

    Kandimalla, Raghuram; Kalita, Sanjeeb; Choudhury, Bhaswati; Dash, Suvakanta; Kalita, Kasturi; Kotoky, Jibon

    2016-01-01

    Poor wound healing is one of the major complication of diabetic patients which arises due to different factors like hyperglycemia, oxidative stress, vascular insufficiency and microbial infections. Candidiasis of diabetic wounds is a difficult to treat condition and potentially can lead to organ amputation. There are a few number of medications available in market to treat this chronic condition; which demands for alternative treatment options. In traditional system of medicine like Ayurveda, essential oil extracted from leaves of Cymbopogon nardus L. (Poaceae) has been using for the treatment of microbial infections, inflammation and pain. In this regard, we have evaluated anti-Candida and anti-inflammatory activity mediated wound healing property of C. nardus essential oil (EO-CN) on candidiasis of diabetic wounds. EO-CN was obtained through hydro-distillation and subjected to Gas chromatography-mass spectroscopy (GC-MS) analysis for chemical profiling. Anti-Candida activity of EO-CN was tested against Candida albicans, C. glabrata and C. tropicalis by in vitro zone of inhibition and minimum inhibitory concentration (MIC) assays. Anti-candidiasis ability of EO-CN was evaluated on C. albicans infected diabetic wounds of mice through measuring candida load on the 7th, 14th, and 21st day of treatment. Further progression in wound healing was confirmed by measuring the inflammatory marker levels and histopathology of wounded tissues on last day of EO-CN treatment. A total of 95 compounds were identified through GC-MS analysis, with major compounds like citral, 2,6-octadienal-, 3,7-dimethyl-, geranyl acetate, citronellal, geraniol, and citronellol. In vitro test results demonstrated strong anti-Candida activity of EO-CN with a MIC value of 25 μg/ml against C. albicans, 50 μg/ml against C. glabrata and C. tropicalis. EO-CN treatment resulted in significant reduction of candida load on diabetic wounds. Acceleration in wound healing was indicated by declined levels of

  1. Essential Oil of Cymbopogon nardus (L. Rendle: A Strategy to Combat Fungal Infections Caused by Candida Species

    Directory of Open Access Journals (Sweden)

    Luciani Gaspar De Toledo

    2016-08-01

    Full Text Available Background: The incidence of fungal infections, especially those caused by Candida yeasts, has increased over the last two decades. However, the indicated therapy for fungal control has limitations. Hence, medicinal plants have emerged as an alternative in the search for new antifungal agents as they present compounds, such as essential oils, with important biological effects. Published data demonstrate important pharmacological properties of the essential oil of Cymbopogon nardus (L. Rendle; these include anti-tumor, anti-nociceptive, and antibacterial activities, and so an investigation of this compound against pathogenic fungi is interesting. Objective: The aim of this study was to evaluate the chemical composition and biological potential of essential oil (EO obtained from the leaves of C. nardus focusing on its antifungal profile against Candida species. Methods: The EO was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS. Testing of the antifungal potential against standard and clinical strains was performed by determining the minimal inhibitory concentration (MIC, time-kill, inhibition of Candida albicans hyphae growth, and inhibition of mature biofilms. Additionally, the cytotoxicity was investigated by the IC50 against HepG-2 (hepatic and MRC-5 (fibroblast cell lines. Results: According to the chemical analysis, the main compounds of the EO were the oxygen-containing monoterpenes: citronellal, geranial, geraniol, citronellol, and neral. The results showed important antifungal potential for all strains tested with MIC values ranging from 250 to 1000 μg/mL, except for two clinical isolates of C. tropicalis (MIC > 1000 μg/mL. The time-kill assay showed that the EO inhibited the growth of the yeast and inhibited hyphal formation of C. albicans strains at concentrations ranging from 15.8 to 1000 μg/mL. Inhibition of mature biofilms of strains of C. albicans, C. krusei and C. parapsilosis occurred

  2. Chemical Composition and Anti-Candidiasis Mediated Wound Healing Property of Cymbopogon nardus Essential Oil on Chronic Diabetic Wounds

    Science.gov (United States)

    Kandimalla, Raghuram; Kalita, Sanjeeb; Choudhury, Bhaswati; Dash, Suvakanta; Kalita, Kasturi; Kotoky, Jibon

    2016-01-01

    Poor wound healing is one of the major complication of diabetic patients which arises due to different factors like hyperglycemia, oxidative stress, vascular insufficiency and microbial infections. Candidiasis of diabetic wounds is a difficult to treat condition and potentially can lead to organ amputation. There are a few number of medications available in market to treat this chronic condition; which demands for alternative treatment options. In traditional system of medicine like Ayurveda, essential oil extracted from leaves of Cymbopogon nardus L. (Poaceae) has been using for the treatment of microbial infections, inflammation and pain. In this regard, we have evaluated anti-Candida and anti-inflammatory activity mediated wound healing property of C. nardus essential oil (EO-CN) on candidiasis of diabetic wounds. EO-CN was obtained through hydro-distillation and subjected to Gas chromatography–mass spectroscopy (GC–MS) analysis for chemical profiling. Anti-Candida activity of EO-CN was tested against Candida albicans, C. glabrata and C. tropicalis by in vitro zone of inhibition and minimum inhibitory concentration (MIC) assays. Anti-candidiasis ability of EO-CN was evaluated on C. albicans infected diabetic wounds of mice through measuring candida load on the 7th, 14th, and 21st day of treatment. Further progression in wound healing was confirmed by measuring the inflammatory marker levels and histopathology of wounded tissues on last day of EO-CN treatment. A total of 95 compounds were identified through GC–MS analysis, with major compounds like citral, 2,6-octadienal-, 3,7-dimethyl-, geranyl acetate, citronellal, geraniol, and citronellol. In vitro test results demonstrated strong anti-Candida activity of EO-CN with a MIC value of 25 μg/ml against C. albicans, 50 μg/ml against C. glabrata and C. tropicalis. EO-CN treatment resulted in significant reduction of candida load on diabetic wounds. Acceleration in wound healing was indicated by declined

  3. A Decentralized Current-Sharing Controller Endows Fast Transient Response to Parallel DC-DC Converters

    DEFF Research Database (Denmark)

    Wang, Haojie; Han, Minxiao; Han, Renke

    2017-01-01

    This paper proposes a decentralized current-sharing control strategy to endow fast transient response to paralleled DC-DC converters systems, such as DC microgrids or distributed power systems. The proposed controller consist of two main control loops: an external voltage droop control for curren...

  4. Fuzzy Logic Controlled DC-DC Converter Based Dynamic Voltage Restorer

    Directory of Open Access Journals (Sweden)

    Mustafa İnci

    2015-12-01

    Full Text Available This paper presents fuzzy logic controlled dc-dc boost converter based Dynamic Voltage Restorer (DVR to compensate severe voltage sag problems in an electrical system. DVR absorbs real power from battery to compensate voltage sags in the system. This condition causes reduction in voltage magnitude of dc-link capacitor. Additionally, DVR requires large dc capacitors to compensate long and severe voltage sags in the system. In this study, dc-dc boost converter is connected to DVR for keeping dc link voltage constant. For this propose, a control algorithm based on Fuzzy Logic (FL control is developed for dc-dc boost converter. The main contribution of this study is that Fuzzy Logic (FL is firstly used to generate reference signal for PWM signals of dc-dc converter applied in DVR. FL is a very flexible controller which keeps the dc link voltage constant during voltage sag. The performance results of proposed study are verified with PSCAD/EMDTC.

  5. Electronic DC transformer with high power density

    NARCIS (Netherlands)

    Pavlovský, M.

    2006-01-01

    This thesis is concerned with the possibilities of increasing the power density of high-power dc-dc converters with galvanic isolation. Three cornerstones for reaching high power densities are identified as: size reduction of passive components, reduction of losses particularly in active components

  6. DC/DC converters for integration of double-layer condensers in onboard power supply; DC/DC-Wandler zur Einbindung von Doppelschichtkondensatoren in das Fahrzeugenergiebordnetz

    Energy Technology Data Exchange (ETDEWEB)

    Polenov, Dieter

    2010-01-15

    The paper discusses DC/DC converters for integration of double layer condensers into the onboard power system. First, requirements on DC/DC converters are listed and compared on the basis of three exemplary applications. A DC/DC converter concept is developed for decoupling transient high-power loads like electric steering systems. Three different topologies are compared using a specially developed method in order to find the best solution for the given application. In order to establish adequate criteria for selecting the switching frequency and inductivities of storage throttles, the influence of the trottle power change on the switching characteristics of the MOSFETs and on certain ranges of EMP interference emissions is investigated. As methods of optimising the operation of the synchronous rectifiers, parallel connection of Schottky diodes and synchronous rectifiers as well as the variation of the shut-off dead times of synchronous rectifiers were investigated. Further, a concept for converter control was developed in consideration of the intended application and topology. Finally, selected aspects for implementation of the DC/DC converter concept are presented as well as the results of experimental investigations.

  7. DC-based magnetic field controller

    Science.gov (United States)

    Kotter, D.K.; Rankin, R.A.; Morgan, J.P.

    1994-05-31

    A magnetic field controller is described for laboratory devices and in particular to dc operated magnetic field controllers for mass spectrometers, comprising a dc power supply in combination with improvements to a Hall probe subsystem, display subsystem, preamplifier, field control subsystem, and an output stage. 1 fig.

  8. Modelling of flow phenomena during DC casting

    NARCIS (Netherlands)

    Zuidema, J.

    2005-01-01

    Modelling of Flow Phenomena during DC Casting Jan Zuidema The production of aluminium ingots, by semi-continuous casting, is a complex process. DC Casting stands for direct chill casting. During this process liquid aluminium transforms to solid aluminium while cooling down. This is not an

  9. DC-based magnetic field controller

    Science.gov (United States)

    Kotter, Dale K.; Rankin, Richard A.; Morgan, John P,.

    1994-01-01

    A magnetic field controller for laboratory devices and in particular to dc operated magnetic field controllers for mass spectrometers, comprising a dc power supply in combination with improvements to a hall probe subsystem, display subsystem, preamplifier, field control subsystem, and an output stage.

  10. Analysis of a Hybrid DC Comparator

    Directory of Open Access Journals (Sweden)

    Li Web

    2006-06-01

    Full Text Available The traditional controllable saturation reactor (CSR consists of single toroidal core, DC (direct current controlled loop (including DC controlled winding and DC biasing source and AC (alternating current excitation loop (including excitation winding and AC source. A detection winding and secondary winding are added up to the CSR configuration and form a hybrid DC comparator. The excitation current is asymmetric waveform when the CSR core is commonly stimulated by both AC and DC biasing sources, which just is the fundamental characteristic for the proposed comparator. Research shows the terminal voltage of the detection winding is asymmetric waveform when the secondary winding of the comparator is open and the CSR core is stimulated both by AC and DC biasing sources. Both theory analysis and experiment verify the feasibility of the differential RMS (root-mean-square between positive and negative half waves of the terminal voltage from the detection winding fitting for the feedback variance to balance DC biasing magnetic potential and form a self-balancing comparator. The zero-flux technique that the primary ampere-turn is equal to the secondary is the function base for the comparator. The operation details of the comparator including the control characteristics both of open-loop and close loop, the satiability judgment criterion, static error property and test range are introduced. The experimental results testify to the truth of the principle of the proposed DC comparator.

  11. Control and dynamic analysis of a parallel-connected single active bridge DC-DC converter for DC-grid wind farm application

    DEFF Research Database (Denmark)

    Park, Kiwoo; Chen, Zhe

    2015-01-01

    This study presents a control strategy and its dynamic analysis of a high-power dc-dc converter, which is constructed with the parallel-connected single active bridge (SAB) dc-dc converters for dc-grid wind farm applications. The structural and operational characteristics of the SAB dc-dc convert...... for dc-grid wind farm applications, an input voltage control method based on the PI control will be introduced and the dynamics of the overall system will be analysed. The analysis results are to be verified by means of simulations and experiments.......This study presents a control strategy and its dynamic analysis of a high-power dc-dc converter, which is constructed with the parallel-connected single active bridge (SAB) dc-dc converters for dc-grid wind farm applications. The structural and operational characteristics of the SAB dc-dc converter...... have several advantages for high-power applications, and the modular concept of the parallel-connected converter is highly beneficial especially for offshore wind farm applications in terms of maintenance cost and fault tolerance. To justify the feasibility of the parallel-connected SAB dc-dc converter...

  12. A Component-Reduced Zero-Voltage Switching Three-Level DC-DC Converter

    DEFF Research Database (Denmark)

    Qin, Zian; Pang, Ying; Wang, Huai

    2016-01-01

    The basic Zero-Voltage Switching (ZVS) three-level DC-DC converter has one clamping capacitor to realize the ZVS of the switches, and two clamping diodes to clamp the voltage of the clamping capacitor. In order to reduce the reverse recovery loss of the diode as well as its cost, this paper...... proposes to remove one of the clamping diodes in basic ZVS three-level DC-DC converter. With less components, the proposed converter can still have a stable clamping capacitor voltage, which is clamped at half of the dc link voltage. Moreover, the ZVS performance will be influenced by removing the clamping...

  13. DC-10 winglet flight evaluation

    Science.gov (United States)

    Taylor, A. B.

    1983-01-01

    Results of a flight evaluation of winglets on a DC-10 Series 10 aircraft are presented. For sensitive areas of comparison, effects of winglets were determined back-to-back with and without winglets. Basic and reduced-span winglet configurations were tested. After initial encounter with low-speed buffet, a number of acceptable configurations were developed. For maximum drag reduction at both cruise and low speeds, lower winglets were required, having leading edge devices on upper and lower winglets for the latter regime. The cruise benefits were enhanced by adding outboard aileron droop to the reduced-span winglet aircraft. Winglets had no significant impact on stall speeds, high-speed buffet boundary, and stability and control. Flutter test results agreed with predictions and ground vibration data. Flight loads measurement, provided in a concurrent program, also agreed with predictions. It was estimated that a production version of the aircraft, using the reduced-span winglet and aileron droop, would yield a 3-percent reduction in fuel burned with capacity payload. This range was 2% greater than with winglets. A 5% reduction in takeoff distance at maximum takeoff weight would also result.

  14. Expression of DC-SIGN and DC-SIGNRs in placentas of HIV-positive patients

    Directory of Open Access Journals (Sweden)

    Komala Pillay

    2014-09-01

    Full Text Available Background. Human dendritic cell-specific intracellular adhesion molecule-3 (ICAM3-grabbing non-integrin (DC-SIGN is a mannose-binding lectin that initiates interaction between dendritic cells and resting T-lymphocytes. DC-SIGN is highly expressed in placental tissue on dendritic cells and Hofbauer cells, and it is suggested that HIV may become adsorbed to DC-SIGN on Hofbauer cells as part of the mechanism of mother-to-child HIV transmission. A possible mechanism of transfer of the virus from the Hofbauer cells to the fetus is the subsequent adsorption to DC-SIGN-related molecules (DC-SIGNRs, present on immediately adjacent capillary vascular endothelium. However, data on DC-SIGN and DC-SIGNR expression in the placenta are few.Methods. Forty term placentas from HIV-positive mothers and 21 term placentas from HIV-negative mothers underwent immunohistochemistry staining for DC-SIGN and DC-SIGNR expression. Five random sets of 10 villi were assessed, and the average number of positive cells were counted in each case. In addition, where possible, maternal and cord blood viral loads and maternal CD4+ counts were performed in the HIV-positive group only.Results. The median maternal CD4+ count was 377 cells/µl and 27% of participants had undetectable viral loads; the median detectable viral load was 3.72 log. Most (97% of the cord bloods tested in infants from HIV-positive mothers had lower than detectable viral loads. HIV-positive cases had significantly greater expression of both DC-SIGNRs (median values in HIV-positive cases, 14.5 positive cells/10 villi (pc/10villi, compared with 11 pc/10villi in HIV-negative cases, p=0.020 and DC-SIGN (median value in HIV-positive cases, 26.5 pc/10villi, compared with 23 pc/10villi in HIV-negative cases, p=0.037. DC-SIGNR expression was also noted in Hofbauer cells and decidual macrophages in addition to endothelium (reported currently. There was no difference in expression of DC-SIGN and DC-SIGNRs in patients

  15. DC-Compensated Current Transformer †

    Science.gov (United States)

    Ripka, Pavel; Draxler, Karel; Styblíková, Renata

    2016-01-01

    Instrument current transformers (CTs) measure AC currents. The DC component in the measured current can saturate the transformer and cause gross error. We use fluxgate detection and digital feedback compensation of the DC flux to suppress the overall error to 0.15%. This concept can be used not only for high-end CTs with a nanocrystalline core, but it also works for low-cost CTs with FeSi cores. The method described here allows simultaneous measurements of the DC current component. PMID:26805830

  16. Study on the Control Algorithm of Two-Stage DC-DC Converter for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Changhao Piao

    2014-01-01

    Full Text Available The fast response, high efficiency, and good reliability are very important characteristics to electric vehicles (EVs dc/dc converters. Two-stage dc-dc converter is a kind of dc-dc topologies that can offer those characteristics to EVs. Presently, nonlinear control is an active area of research in the field of the control algorithm of dc-dc converters. However, very few papers research on two-stage converter for EVs. In this paper, a fixed switching frequency sliding mode (FSFSM controller and double-integral sliding mode (DISM controller for two-stage dc-dc converter are proposed. And a conventional linear control (lag is chosen as the comparison. The performances of the proposed FSFSM controller are compared with those obtained by the lag controller. In consequence, the satisfactory simulation and experiment results show that the FSFSM controller is capable of offering good large-signal operations with fast dynamical responses to the converter. At last, some other simulation results are presented to prove that the DISM controller is a promising method for the converter to eliminate the steady-state error.

  17. Studi Komparasi Fungsi Keanggotaan Fuzzy sebagai Kontroler Bidirectional DC-DC Converter pada Sistem Penyimpan Energi

    Directory of Open Access Journals (Sweden)

    Eka Prasetyono

    2015-09-01

    Full Text Available Bidirectional DC-DC converter is needed in the energy storage system. The converter topology used in this paper was a non-isolated bidirectional DC-DC buck-boost converter. This converter worked in two ways, which the charging mode stored energy into battery when load current was less than nominal main DC current (set point and discharging mode transferred energy from battery to the load when its current exceeded set point value. Both of these modes worked automatically according to the load current. The charging and discharging currents were controlled by fuzzy logic controller which was implemented on microcontroller ARM Cortex-M4F STM32F407VG. This paper compares two types of fuzzy membership function (triangular and sigmoid in controlling bidirectional DC-DC converter. The results showed that fuzzy logic controller with triangle membership function and sigmoid as control bidirectional DC-DC converter had no significant different response, both had an average error for charging and discharging process under 4% with ripple current on the main DC bus around 0.5%. The computing time of program for fuzzy logic controller with triangular membership functions had 19.01% faster than sigmoid, and fuzzy logic computation time on a microcontroller with hardware floating point was 60% faster than software floating point.

  18. A Double Phase-Shift Control Strategy for A Full-Bridge Three-Level DC/DC Converter

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Gong, Zheng

    2016-01-01

    In this paper, a double phase-shift control strategy is proposed for the full-bridge three-level (FBTL) DC/DC converter applied into DC distribution systems with the medium DC bus voltage. By utilizing the proposed control strategy, the voltage change rate dv/dt and voltage stress of the transfor......In this paper, a double phase-shift control strategy is proposed for the full-bridge three-level (FBTL) DC/DC converter applied into DC distribution systems with the medium DC bus voltage. By utilizing the proposed control strategy, the voltage change rate dv/dt and voltage stress...

  19. NAMMA DC-8 DROPSONDE V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The DC-8 dropsonde system uses an integrated, highly accurate, GPS-located atmospheric profiling dropsonde, which measures and records current atmospheric conditions...

  20. GRIP DC-8 DROPSONDE V3

    Data.gov (United States)

    National Aeronautics and Space Administration — The GRIP DC-8 Dropsonde V3 dataset consists of atmospheric pressure, dry-bulb temperature, dew point temperature, relative humidity, wind direction, wind speed, and...

  1. Early Oscillation Detection for Hybrid DC/DC Converter Fault Diagnosis

    Science.gov (United States)

    Wang, Bright L.

    2011-01-01

    This paper describes a novel fault detection technique for hybrid DC/DC converter oscillation diagnosis. The technique is based on principles of feedback control loop oscillation and RF signal modulations, and Is realized by using signal spectral analysis. Real-circuit simulation and analytical study reveal critical factors of the oscillation and indicate significant correlations between the spectral analysis method and the gain/phase margin method. A stability diagnosis index (SDI) is developed as a quantitative measure to accurately assign a degree of stability to the DC/DC converter. This technique Is capable of detecting oscillation at an early stage without interfering with DC/DC converter's normal operation and without limitations of probing to the converter.

  2. The Topologies Research of a Soft Switching Bidirectional DC/DC Converter

    DEFF Research Database (Denmark)

    Zhang, Qi; Zhang, Yongping; Sun, Xiangdong

    2017-01-01

    A soft-switching solution implemented to the traditional bidirectional DC/DC converter is developed. The soft-switching cell, which composed of three auxiliary switches, one resonant capacitor and one resonant inductor, is equipped in the traditional bidirectional DC/DC converter to realize circuit...... circle. And the proposed topology of bidirectional soft-switching dc-dc converter(TASBC) performs ideal soft switching at boost operations. The characteristics of the proposed converter has been verified by MATLAB simulations and experimental results....... from a hard turning off process in one of the auxiliary switches, while the others experience the soft operation. As for the other method, the zero voltage or zero current transmissions in all switches are realized, however, the relative higher but fixed conduction losses are introduced by the resonant...

  3. Modelling and Simulation of Digital Compensation Technique for dc-dc Converter by Pole Placement

    Science.gov (United States)

    Shenbagalakshmi, R.; Sree Renga Raja, T.

    2015-09-01

    A thorough and effective analysis of the dc-dc converters is carried out in order to achieve the system stability and to improve the dynamic performance. A small signal modelling based on state space averaging technique for dc-dc converters is carried out. A digital state feedback gain matrix is derived by pole placement technique in order to achieve the stability of a completely controllable system. A prediction observer for the dc-dc converters is designed and a dynamic compensation (observer plus control law) is provided using separation principle. The output is very much improved with zero output voltage ripples, zero peak overshoot, and much lesser settling time in the range of ms and with higher overall efficiency (>90 %).

  4. Optimized photovoltaic generator-water electrolyser coupling through a controlled DC-DC converter

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Valverde, R.; Miguel, C.; Urbina, A. [Universidad Politecnica de Cartagena, Departamento de Electronica, Tecnologia de Computadoras y Proyectos, Plaza del Hospital, 1, Cartagena, 30203 Murcia (Spain); Martinez-Bejar, R. [Universidad de Murcia, Departamento de Ingenieria de la Informacion y las Comunicaciones, Facultad de Informatica, Campus de Espinardo, 30071 Murcia (Spain)

    2008-10-15

    The coupling of a photovoltaic generator and an electrolyser is one of the most promising options for obtaining hydrogen from a renewable energy source. Both are well known technologies, however, since the high variability of the solar radiation, an efficient coupling still presents some challenges. Direct or through a DC-DC converter couplings are the options in isolated applications. In this work, three models, respectively, for a photovoltaic (PV) generator, a controlled DC-DC converter and a complete proton exchange membrane (PEM) electrolyser have been designed by using Matlab/Simulink. A PV-electrolyser specific algorithm to search for the optimum and safe working point for both elements is presented. Simulation results demonstrate that the use of a controlled DC-DC converter with the proposed algorithm shows better adaptability to the variable radiation conditions than the other coupling options. Therefore, it leads to a better compliance between the electrolyser and the sizing of the PV generator. (author)

  5. Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1

    Science.gov (United States)

    Lee, F. C.; Mahmoud, M. F.; Yu, Y.

    1980-01-01

    The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.

  6. dc illusion and its experimental verification

    Science.gov (United States)

    Liu, Min; Lei Mei, Zhong; Ma, Xiang; Cui, Tie Jun

    2012-07-01

    Based on the transformation optics method, we propose a dc illusion device, which can transform a metallic object into a magnified dielectric object using anisotropic conducting materials. Utilizing the analogy between electric conductivities and resistor networks, we design and fabricate the device using metal film resistors. The practical measurement data agree very well with simulation results. The proposed dc illusion device is easy to process and measure, and thus has potential applications in various sectors.

  7. Allelopathic effect of melissa, lemongrass, lavender and rosemary on germination and vigor of lettuce seeds

    Directory of Open Access Journals (Sweden)

    Daniela Aparecida Teixeira

    2014-09-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2014v27n4p37 The objective of this study was to evaluate the influence of four herbal plants on the germination and vigor of lettuce seeds, using aqueous preparations and teas of Melissa officinalis L. (melissa, Rosmarinus officinalis L. (rosemary, Lavandula angustifolia Mill. (lavender and Cymbopogon citratus (DC. Stapf. (lemongrass. A randomized complete block design was used with 9 treatments and 4 repetitions. The treatments were: melissa tea, melissa aqueous preparation, rosemary tea, rosemary aqueous preparation, lavender tea, lavender aqueous preparation, lemongrass tea, lemongrass aqueous preparation and control. The variables evaluated were: germination speed index, percentage of abnormal plants, percentage of germinated plants, fresh matter, dry matter, shoot length and radicle length. Lemongrass showed negative allelopathic effects on germination and vigor of L. sativa L. Melissa tea had a stimulatory effect.

  8. Interleaved DC-DC Converter with Discrete Duty Cycle and Open Loop Control

    Directory of Open Access Journals (Sweden)

    Kroics K.

    2016-08-01

    Full Text Available The authors present the control principle of the multiphase interleaved DC-DC converter that can be used to vastly reduce output current ripple of the converter. The control algorithm can be easily implemented by using microcontroller without current loop in each phase. The converter works in discontinuous conduction mode (DCM but close to boundary conduction mode (BCM. The DC-DC converter with such a control algorithm is useful in applications that do not require precise current adjustment. The prototype of the converter has been built. The experimental results of the current ripple are presented in the paper.

  9. Design of the DC-DC power stage of the capacitor charger for MAXIDISCAP power converters

    CERN Document Server

    Cravero, Jean-Marc

    2013-01-01

    This technical report presents the design of the DC-DC power stage of the capacitor charger for MAXIDISCAP power converters. The power stage is based on a half bridge series resonant converter in Discontinuous Conduction Mode (DCM). This simple and robust topology allows obtaining a current source behavior with a low switching losses power stage. The associated control stage is implemented using a commercial controller which has differenti nternal circuits that allows a high integration of the converter control system. The report presents the design and tuning criteria for the DC-DC converter, including the power stage and the control system.

  10. Diseño de un convertidor DC-DC Flyback para aplicaciones fotovoltaicas

    OpenAIRE

    MOLINA TOBOSO, MARIANO

    2017-01-01

    The aim of this project is to design a Flyback DC-DC converter. The values of all the internal elements of the converter, including the transformer, will be calculated in order to obtain the desired response. Afterwards several simulations will be carried out to test the results. Este trabajo de fin de grado tiene como objetivo el diseño de un convertidor elevador DC-DC tipo Flyback propuesto en la asignatura de Sistemas Electónicos para Energías Renovables. Se trata de un convertidor D...

  11. Laboratory manual for pulse-width modulated DC-DC power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2015-01-01

    Designed to complement a range of power electronics study resources, this unique lab manual helps students to gain a deep understanding of the operation, modeling, analysis, design, and performance of pulse-width modulated (PWM) DC-DC power converters.  Exercises focus on three essential areas of power electronics: open-loop power stages; small-signal modeling, design of feedback loops and PWM DC-DC converter control schemes; and semiconductor devices such as silicon, silicon carbide and gallium nitride. Meeting the standards required by industrial employers, the lab manual combines program

  12. High power density dc/dc converter: Component selection and design

    Science.gov (United States)

    Divan, Deepakraj M.

    Further work pertaining to design considerations for the new high power, high frequency dc/dc converters is discussed. The goal of the project is the development of high power, high power density dc/dc converters at power levels in the multi-kilowatt to megawatt range for aerospace applications. The prototype converter is rated for 50 kW at a switching frequency of 50 kHz, with an input voltage of 200 Vdc and an output of 2000 Vdc. The overall power density must be in the vicinity of 0.2 to 0.3 kg/kW.

  13. Operation and control of a DC-grid offshore wind farm under DC transmission system faults

    DEFF Research Database (Denmark)

    Deng, Fujin; Chen, Zhe

    2013-01-01

    So far, all existing offshore wind farms have an ac collection system, and the collected power in the offshore wind farm is sent to an onshore ac grid through high-voltage ac (HVAC) or DC (HVDC) transmission lines. However, future of fshore wind farms may use dc also for power collection. Consequ......So far, all existing offshore wind farms have an ac collection system, and the collected power in the offshore wind farm is sent to an onshore ac grid through high-voltage ac (HVAC) or DC (HVDC) transmission lines. However, future of fshore wind farms may use dc also for power collection....... Consequently, the protection and control strategies of dc systems need to be established. This paper studies a dc-grid offshore wind farm, where the wind power collection system and power transmission system adopt dc technology. In this paper, the redundancy of the HVDC transmission system under faults...... is studied, and a fault ridethrough strategy for the dc-grid offshore wind farm is proposed. The proposed strategy can effectively minimize the impacts of the power transmission system disturbance on the offshore wind farm, and on the ac grid. A dc-grid offshore wind farm example is simulated with PSCAD...

  14. Influence of aqueous crude extracts of medicinal plants on the osmotic stability of human erythrocytes.

    Science.gov (United States)

    de Freitas, Mariana V; Netto, Rita de Cássia M; da Costa Huss, Juliana C; de Souza, Tatiana Maria T; Costa, Júnia O; Firmino, Cynthia B; Penha-Silva, Nilson

    2008-02-01

    This work analyzed the effects of the aqueous crude extracts of Artemisia absinthium L., Lippia sp., Bryophyllum sp., Solidago microglossa DC, Cymbopogon citratus DC and Mentha x villosa HUDSON on the osmotic stability of human erythrocytes. Hemolysis was monitored by measurement of absorbance at 540 nm following addition of erythrocytes to NaCl solutions of varying concentration. Absorbance was fitted to sigmoid regression curves given by the Boltzmann equation, and hemolysis was characterized by the NaCl concentration leading to lysis of 50% of cells (H(50)), and by the intensity (H) and the amplitude (dS) of the lysis effect. The parameters were determined in the absence and presence of the crude extracts. The extracts of Artemisia absinthium, Lippia sp., C. citratus and M. villosa protected human erythrocytes against hypotonic shock, as evidenced by a decrease in the values of H and H(50) compared to the control solution (p<0.05). The extracts of Bryophyllum sp. and S. microglossa enhanced hemolysis, since their H(50) values were higher than in the control group (p<0.05), but they also showed protective effects, as evidenced by a decrease in H and an increase in dS.

  15. Magnetically integrated high step-up resonant DC-DC converter for distributed photovoltaic systems

    DEFF Research Database (Denmark)

    Vinnikov, Dmitri; Chub, Andrii; Liivik, Elizaveta

    2017-01-01

    In this paper magnetically integrated resonant single-switch quasi-Z-source DC-DC converter is evaluated as a candidate topology for the low-cost photovoltaic microconverter. The derivation of the topology and its basic operation principle are explained. Generalized design guidelines...

  16. Selection of DC/DC converter for offshore wind farms with MVDC power collection

    DEFF Research Database (Denmark)

    Dincan, Catalin Gabriel; Kjær, Philip Carne; Chen, Yu-Hsing

    2017-01-01

    Four DC/DC converters are analyzed and compared with respects to availability, efficiency, ratings, repair costs and power density. Intended application is offshore wind farms with MVDC power collection. The selected topology is a new series resonant converter, which offers 99% efficiency across...... the entire operational range, but needs components designed for high voltage stress....

  17. Analysis and design of PPFHB bidirectional DC-DC converter with coupled inductors

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael Andreas E.

    2009-01-01

    In this paper, a novel push-pull-forward half-bridge (PPFHB) bi-directional DC-DC converter with coupled inductors is proposed. All switches can operate under zero-voltage-switching (ZVS). The operation principle with phase-shift modulation scheme, characteristics of coupled inductors, the steady...

  18. Modeling methodology of the conducted emission of a DC-DC converter board

    OpenAIRE

    Boyer, Alexandre; Gonzalez Sentis, Manuel; Ghfiri, Chaimae; Durier, André

    2017-01-01

    International audience; This paper proposes a methodology to model an electronic board according to a bottom-up approach. This method is applied to build the model of a synchronous buck DC-DC converter board for conducted emission prediction purpose. The different steps to select the model terminals and the construction of the component and PCB interconnect models are described.

  19. A New Sliding Mode Controller for DC/DC Converters in Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    M. Sarvi

    2013-01-01

    Full Text Available DC/DC converters are widely used in many industrial and electrical systems. As DC/DC converters are nonlinear and time-variant systems, the application of linear control techniques for the control of these converters is not suitable. In this paper, a new sliding mode controller is proposed as the indirect control method and compared to a simple direct control method in order to control a buck converter in photovoltaic applications. The solar arrays are dependent power sources with nonlinear voltage-current characteristics under different environmental conditions (insolation and temperature. From this point of view, the DC/DC converter is particularly suitable for the application of the sliding mode control in photovoltaic application, because of its controllable states. Simulations are performed in Matlab/Simulink software. The simulation results are presented for a step change in reference voltage and input voltage as well as step load variations. The simulations results of proposed method are compared with the conventional PID controller. The results show the good performance of the proposed sliding mode controller. The proposed method can be used for the other DC/DC converter.

  20. Integrated S-band transmitter with on-chip DC-DC converter and control loop

    NARCIS (Netherlands)

    Brouzes, H.; Geurts, S.; Besselink, M.; Telli, A.; Hek, A.P. de; Bent, G. van der; Vliet, F.E. van

    2012-01-01

    A highly integrated high-power transmitter has been designed in a high breakdown GaAs MMIC technology. The transmitter includes, on top of an S-Band 10 W class-F HPA, a DC/DC converter and its associated gate driver, the full voltage regulation control loop, which provides a significant step for

  1. Y-Source Boost DC/DC Converter for Distributed Generation

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Loh, Poh Chiang; Blaabjerg, Frede

    2015-01-01

    This paper introduces a versatile Y-source boost dc/dc converter intended for distributed power generation, where high gain is often demanded. The proposed converter uses a Y-source impedance network realized with a tightly coupled three-winding inductor for high voltage boosting that is presently...

  2. Common mode noise in three-level DC-DC converters

    CSIR Research Space (South Africa)

    Grobler, Inus

    2009-09-01

    Full Text Available that three-level buck DC-DC converters in general generate much lower common mode currents than conventional two-level buck converters. Further, reductions in common mode currents are achieved by using the improved three-level topologies that have been...

  3. A DC-DC Converter with Wide Input Voltage Range for Fuel Cell and Supercapacitor Application

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael Andreas E.

    2009-01-01

    This paper proposes a novel phase-shift plus duty cycle controlled hybrid bi-directional DC-DC converter based on fuel cells and supercapacitors. The described converter employs two high frequency transformers to couple the half-bridge and full-bridge circuits together in the primary side...

  4. A VHF Class E DC-DC Converter with Self-Oscillating Gate Driver

    DEFF Research Database (Denmark)

    Andersen, Toke Meyer; Christensen, Søren K.; Knott, Arnold

    2011-01-01

    This paper describes the analysis and design of a DC-DC converter topology which is operational at frequencies in the Very High Frequency (VHF) band ranging from 30 MHz − 300 MHz. The presented topology, which consists of a class E inverter, class E rectifier, and self-oscillating gate driver, is...

  5. Very High Frequency Resonant DC/DC Converters for LED Lighting

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    This paper presents a very high frequency DC/DC converter for LED lighting. Several resonant topologies are compared and their usability discussed. At the end the resonant SEPIC converter is chosen based on the achievable power density and total bill of material. Simulations of a 51 MHz converter...

  6. High-Voltage DC-DC Converter Topology for PV Energy Utilization - Investigation and Implementation

    DEFF Research Database (Denmark)

    Sanjeevikumar, Padmanaban; Blaabjerg, Frede; Wheeler, Patrick

    2017-01-01

    This paper exploited the utilization of photovoltaic (PV) energy system with high-voltage (HV) output DC-DC converter. Classical boost converters are used for both renewable energy integration and HV applications, but limited by reducing output/efficiency in performance. Moreover, as parasitic el...

  7. Four Quadrants Integrated Transformers for Dual-input Isolated DC-DC Converters

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Zhang, Zhe; Andersen, Michael A. E.

    2012-01-01

    A common limitation of power coupling effect in some known multiple-input dc-dc converters has been addressed in many literatures. In order to overcome this limitation, a new concept for decoupling the primary windings in the integrated multiple-winding transformers based on 3-dimensional (3D) sp...

  8. Expression of DC-SIGN and DC-SIGNRs in placentas of HIV ...

    African Journals Online (AJOL)

    ICAM3)-grabbing non-integrin (DC-SIGN) is a mannose-binding lectin that initiates interaction between dendritic cells and resting T-lymphocytes. DC-SIGN is highly expressed in placental tissue on dendritic cells and Hofbauer cells, and it is ...

  9. A Bidirectional Multi-Port DC-DC Converter Integrating Voltage Equalizer

    DEFF Research Database (Denmark)

    Chen, Jianfei; Hou, Shiying; Deng, Fujin

    2015-01-01

    A novel bidirectional multi-port dc-dc converter integrating voltage equalizer based on switched-capacitor voltage accumulator (SCVA) is proposed. It has two operating modes of charging and discharging for battery modules. All battery modules are connected in series indirectly and can be equalized...

  10. High Efficiency Interleaved Bi-Directional ZVS DC-DC Converter

    DEFF Research Database (Denmark)

    Zafar Ullah Khan, M.; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar

    2013-01-01

    A High Efficiency Interleaved Bi-Directional ZVS DC-DC converter is presented in this paper. This converter can be operated in both buck and boost mode. CoolMOS is used as a power device to achieve low conduction losses and fast turn off. The value of inductance is selected such that the Cool...

  11. Five-Level Active-Neutral-Point-Clamped DC/DC Converter

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Chen, Zhe

    2016-01-01

    Multi-level converters are getting more and more attentions because of their obvious merits such as lower voltage stress and harmonic, smaller size of output filters, and so on. In this paper, a five-level active-neutral-point-clamped (5L-ANPC) dc/dc converter is proposed for power transfer...

  12. single-phase dc phase dc-ac boost converter ac boost converter

    African Journals Online (AJOL)

    User

    This paper describes a new power conversion circuit dc-dc boost converter. It boost converter. It boost converter. It comprises an H comprises an H. Change of load .... A full-wave rectified signal is used to produce an AC reference voltage v* o. The outer voltage loop generates the reference current command i* f. A common.

  13. High voltage conversion ratio, switched C & L cells, step-down DC-DC converter

    DEFF Research Database (Denmark)

    Pelan, Ovidiu; Muntean, Nicolae; Cornea, Octavian

    2013-01-01

    The paper presents a high voltage conversion ratio DC-DC step-down topology obtained from a classical buck converter associated with an input switched-capacitor cell and an output switched-inductor cell. Analytical descriptions, the voltage and current limits of the main components are synthesize...

  14. Comparative efficiency evaluation of buck and hybrid buck DC-DC converters for automotive applications

    DEFF Research Database (Denmark)

    Pelan, Ovidiu; Cornea, Octavian; Muntean, Nicolae

    2014-01-01

    This paper presents and discusses design considerations and efficiency investigation of a conventional step-down and a hybrid switched-capacitor DC-DC converter. Three MOSFETs with low on-resistance have been tested for each converter in order to find the most adequate switch for this application...

  15. Bidirectional DC-DC converter fed drive for electric vehicle system

    African Journals Online (AJOL)

    ATHARVA

    During acceleration and normal modes the power flow is from battery to motor where as during braking or regenerative mode the kinetic energy of the motor is converted into electrical energy and fed back to battery. The DC-DC converter is required to perform mainly two functions: first to match the battery voltage to the ...

  16. Optimal Design of Hybrid AC/DC Microgrids

    OpenAIRE

    Lotfi,Hossein; Khodaei, Amin; Bahramirad, Shay; Bollen, Math

    2017-01-01

    DC loads (such as computers, data centres, electric vehicle chargers, and LED lamps) and dc distributed energy resources (such as fuel cells, solar photovoltaics, and energy storages) are rapidly growing in electric power systems, so dc systems are being introduced as emerging practical investment solutions compared to traditional ac options. DC microgrids offer several advantages such as the elimination of need for synchronizing generators and easier supply of dc loads. Hybrid microgrids can...

  17. Voltage control of DC islanded microgrids

    DEFF Research Database (Denmark)

    Tucci, Michele; Riverso, Stefano; Quintero, Juan Carlos Vasquez

    2015-01-01

    We propose a new decentralized control scheme for DC Islanded microGrids (ImGs) composed by several Distributed Generation Units (DGUs) with a general interconnection topology. Each local controller regulates to a reference value the voltage of the Point of Common Coupling (PCC) of the correspond......We propose a new decentralized control scheme for DC Islanded microGrids (ImGs) composed by several Distributed Generation Units (DGUs) with a general interconnection topology. Each local controller regulates to a reference value the voltage of the Point of Common Coupling (PCC...

  18. Hierarchical Control for Multiple DC Microgrids Clusters

    DEFF Research Database (Denmark)

    Shafiee, Qobad; Dragicevic, Tomislav; Vasquez, Juan Carlos

    2014-01-01

    . Another distributed policy is employed then to regulate the power flow among the MGs according to their local SOCs. The proposed distributed controllers on each MG communicate with only the neighbor MGs through a communication infrastructure. Finally, the small signal model is expanded for dc MG clusters......This paper presents a distributed hierarchical control framework to ensure reliable operation of dc Microgrid (MG) clusters. In this hierarchy, primary control is used to regulate the common bus voltage inside each MG locally. An adaptive droop method is proposed for this level which determines...

  19. Stability analysis of a high-step-Up DC grid-connected two-stage boost DC-DC converter

    Directory of Open Access Journals (Sweden)

    El Aroudi A.

    2014-01-01

    Full Text Available High conversion ratio switching converters are used whenever there is a need to step-up dc source voltage level to a much higher output dc voltage level such as in photovoltaic systems, telecommunications and in some medical applications. A simple solution for achieving this high conversion ratio is by cascading different stages of dc-dc boost converters. The individual converters in such a cascaded system are usually designed separately applying classical design criteria. However these criteria may not be applicable for the complete cascaded system . This paper first presents a glimpse on the bifurcation behavior that a cascade connection of two boost converters can exhibit. It is shown that the desired periodic orbit can undergo period doubling leading to subharmonic oscillations and chaotic regimes. Then, in order to simplify the analysis the second stage is considered as constant current sink and design-oriented analysis is carried out to obtain stability boundaries in the parameter space by taking into account slope interactions between the state variables in the two-different stages.

  20. Anti-tumor potential of total alkaloid extract of Prosopis juliflora DC ...

    African Journals Online (AJOL)

    Jane

    2011-08-15

    Aug 15, 2011 ... pathovars. Arch. of Phytopathol. Plant Protection. 42(11): 1033-. 1041. Sharma PR, Mondhe DM, Muthiah S, Pal HC (2009). Anticancer activity of an essential oil from Cymbopogon flexuosus. Chemico-Biol. Interactions. 179:160-168. Shearman MS, Hawtin SR, Tailor VJ (1995). The intra cellular component.

  1. Design and modelling of high gain DC-DC converters for fuel cell hybrid electric vehicles

    Science.gov (United States)

    Elangovan, D.; Karthigeyan, V.; Subhanu, B.; Ashwin, M.; Arunkumar, G.

    2017-11-01

    Transportation (Diesel and petrol internal combustion engine vehicles) approximately contributes to 25.5% of total CO2 emission. Thus diesel and petrol engine vehicles are the most dominant contributors of CO2 emission which leads global warming which causes climate change. The problem of CO2 emission and global warming can be reduced by focusing on renewable energy vehicles. Out of the available renewable energy sources fuel cell is the only source which has reasonable efficiency and can be used in vehicles. But the main disadvantage of fuel cell is its slow response time. So energy storage systems like batteries and super capacitors are used in parallel with the fuel cell. Fuel cell is used during steady state vehicle operation while during transient conditions like starting, acceleration and braking batteries and super capacitors can supply or absorb energy. In this paper a unidirectional fuel cell DC-DC converter and bidirectional energy storage system DC-DC converter is proposed, which can interface dc sources at different voltage levels to the dc bus and also it can independently control the power flow from each energy source to the dc bus and vice versa. The proposed converters are designed and simulated using PSIM version 9.1.1 and gate pulse pattern, input and output voltage waveforms of the converters for steady state operation are studied.

  2. DC-Link Compensation Method for Slim DC Link Drives Fed by Soft Grid

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Rosendahl Andersen, Henrik; Lazar, Radu

    2010-01-01

    Slim DC-link PWM (AC) drives for lowperformance applications are emerging on the market. Such drives equipped with a small DC-link capacitance exhibit instability tendencies, if installed on a soft line, giving a degraded performance. The total harmonic distortion (THD) and the partially weighted...... method, which ensures the stability of the slim DC-link on a soft grid. The proposed compensation method may be used for open- and closedloop control schemes, requiring a small overhead in the digital implementation.......Slim DC-link PWM (AC) drives for lowperformance applications are emerging on the market. Such drives equipped with a small DC-link capacitance exhibit instability tendencies, if installed on a soft line, giving a degraded performance. The total harmonic distortion (THD) and the partially weighted...... harmonic distortion (PWHD) of the line current are degraded, if resonance between the line impedance and the DC-link capacitance occurs. Likewise, the motor performance is affected negatively giving extra torque ripple, vibration and acoustic-noise emission. This paper proposes a novel DC-link compensation...

  3. Effect of DC Link Control Strategies on Multiterminal AC-DC Power Flow

    Directory of Open Access Journals (Sweden)

    Shagufta Khan

    2015-01-01

    Full Text Available For power-flow solution of power systems incorporating multiterminal DC (MTDC network(s, five quantities are required to be solved per converter. On the other hand, only three independent equations comprising two basic converter equations and one DC network equation exist per converter. Thus, for solution, two additional equations are required. These two equations are derived from the control specifications adopted for the DC links. Depending on the application, several combinations of valid control specifications are possible. Each combination of a set of valid control specifications is known as a control strategy. The number of control strategies increases with an increase in the number of the DC terminals or converters. It is observed that the power-flow convergence of integrated AC-MTDC power systems is strongly affected by the control strategy adopted for the DC links. This work investigates the mechanism by which different control strategies affect the power-flow convergence pattern of AC-MTDC power systems. To solve the DC variables in the Newton-Raphson (NR power-flow model, sequential method is considered in this paper. Numerous case studies carried out on a three-terminal DC network incorporated in the IEEE-300 bus test system validate this.

  4. Applicability of citronella oil (Cymbopogon winteratus) for the prevention of mosquito-borne diseases in the rural area of Tikapur, far-western Nepal.

    Science.gov (United States)

    Sajo, Ma Easter Joy; Song, Soon-Bong; Bajgai, Johny; Kim, Young-Je; Kim, Pan-Suk; Ahn, Dong-Won; Khanal, Narendra; Lee, Kyu-Jae

    2015-01-01

    Mosquito-borne diseases are a serious global problem, particularly in tropical and sub-tropical countries such as Nepal. Citronella oil is a natural mosquito repellent as well as a local fragrance in Nepal, which is accessible at very low cost because citronella plants are widely cultivated in rural areas of the Terai belt in Nepal. This study was conducted using a real-life randomized controlled pilot trial to confirm the effectiveness and applicability of locally-produced citronella oil as a mosquito repellent for the prevention of mosquito-borne diseases in Nepal. A repellency activity test was performed with 100% citronella oil (Cymbopogon winteratus) from April to May 2013 in the Tikapur Municipality of the Kailali district, Nepal. The test was divided into two trials: an indoor exposure (IE) test (N=101) and an outdoor exposure (OE) test (N=140) from 5.00 pm to 7.00 pm. Each trial contained an experimental citronella oil-applied group and a non-applied (control) group. The outcome measures were the protective effect of citronella oil against mosquitoes, the number of mosquito bites, the repellency percentage, the smell satisfaction and the irritation level. Experimental group had a significant protective effect against mosquito bites in IE (96.5%, n=57) and OE (95.7%, n=70) tests compared to the control group in IE (29.5%, n=44) and OE (28.6%, n=70) tests (experimental vs control groups, pNepal.

  5. Upregulation of Mitf by Phenolic Compounds-Rich Cymbopogon schoenanthus Treatment Promotes Melanogenesis in B16 Melanoma Cells and Human Epidermal Melanocytes

    Directory of Open Access Journals (Sweden)

    Myra O. Villareal

    2017-01-01

    Full Text Available Melanin provides inherent protection against skin cancer by absorbing broad-spectrum radiant energy of UV radiation. Cutaneous malignant melanoma incidence has recently been observed to increase and the frequency is closely associated with the skin color, highlighting the importance of skin pigmentation. Here, we showed how melanin biosynthesis is enhanced by treatment with phenolic compounds-rich Cymbopogon schoenanthus (CYM in B16 murine melanoma cells and human epidermal melanocytes (HEM. CYM increased the melanin content of the cells by upregulating the expression of tyrosinase (TYR, tyrosinase-related protein 1 (TRP1, and dopachrome tautomerase (DCT at the protein and mRNA levels, comparable to the effect of α-melanocyte-stimulating hormone (MSH, in both B16 cells and HEM. Moreover, global gene expression analysis showed that at least 44 pigmentation-associated genes were modulated, including the microphthalmia-associated transcription factor (Mitf and its transcriptional regulators (Sox10, Pax3, and Lef1. Upregulation of copper transport-associated gene Atp7b indicates that CYM also promotes tyrosinase activity. CYM upregulated Mitf and possibly activates tyrosinase enzyme, providing evidence for its possible use to promote melanogenesis and as a therapeutic agent against hypopigmentation disorders.

  6. Comparison of solar panel cooling system by using dc brushless fan and dc water

    Science.gov (United States)

    Irwan, Y. M.; Leow, W. Z.; Irwanto, M.; M, Fareq; Hassan, S. I. S.; Safwati, I.; Amelia, A. R.

    2015-06-01

    The purpose of this article is to discuss comparison of solar panel cooling system by using DC brushless fan and DC water pump. Solar photovoltaic (PV) power generation is an interesting technique to reduce non-renewable energy consumption and as a renewable energy. The temperature of PV modules increases when it absorbs solar radiation, causing a decrease in efficiency. A solar cooling system is design, construct and experimentally researched within this work. To make an effort to cool the PV module, Direct Current (DC) brushless fan and DC water pump with inlet/outlet manifold are designed for constant air movement and water flow circulation at the back side and front side of PV module representatively. Temperature sensors were installed on the PV module to detect temperature of PV. PIC microcontroller was used to control the DC brushless fan and water pump for switch ON or OFF depend on the temperature of PV module automatically. The performance with and without cooling system are shown in this experiment. The PV module with DC water pump cooling system increase 3.52%, 36.27%, 38.98%in term of output voltage, output current, output power respectively. It decrease 6.36 °C compare than to PV module without DC water pump cooling system. While DC brushless fan cooling system increase 3.47%, 29.55%, 32.23%in term of output voltage, output current, and output power respectively. It decrease 6.1 °C compare than to PV module without DC brushless fan cooling system. The efficiency of PV module with cooling system was increasing compared to PV module without cooling system; this is because the ambient temperature dropped significantly. The higher efficiency of PV cell, the payback period of the system can be shorted and the lifespan of PV module can also be longer.

  7. Analysis of DC/DC Converter Efficiency for Energy Storage System Based on Bidirectional Fuel Cells

    DEFF Research Database (Denmark)

    Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

    2013-01-01

    Renewable energy sources are fluctuating depending on the availability of the energy source. For this reason, energy storage is becoming more important and bidirectional fuel cells represent an attractive technology. Fuel cells require highcurrent low-voltage dc-dc or dc-ac converters as power...... interface to the grid. In power electronics, the converter efficiency is characterized at fixed operating voltage for various output power. This type of characterization is not suitable for fuel cells, since as the power from the fuel cell increases, the cell voltage decreases. This paper analyses how...

  8. Modeling and simulation for micro DC motor based on simulink

    Science.gov (United States)

    Shen, Hanxin; Lei, Qiao; Chen, Wenxiang

    2017-09-01

    The micro DC motor has a large market demand but there is a lack of theoretical research for it. Through detailed analysis of the commutation process of micro DC motor commutator, based on micro DC motor electromagnetic torque equation and mechanical torque equation, with the help of Simulink toolkit, a triangle connection micro DC motor simulation model is established. By using the model, a sample micro DC motor are simulated, and an experimental measurements has been carried on the sample micro DC motor. It is found that the simulation results are consistent with theoretical analysis and experimental results.

  9. Power Quality in DC Power Distribution Systems and Microgrids

    Directory of Open Access Journals (Sweden)

    Stephen Whaite

    2015-05-01

    Full Text Available This review paper discusses power quality considerations for direct current (DC electric power distribution systems, particularly DC microgrids. First, four selected sample DC architectures are discussed to provide motivation for the consideration of power quality in DC systems. Second, a brief overview of power quality challenges in conventional alternating current (AC distribution systems is given to establish the field of power quality. Finally, a survey of literature addressing power quality issues in DC systems is presented, and necessary power quality considerations in DC distribution system design and operation are discussed.

  10. Design and dSpace interfacing of current fed high gain dc to dc boost converter for low voltage applications

    Science.gov (United States)

    Mukhopadhyay, Debraj; Das, Subhrajit; Arunkumar, G.; Elangovan, D.; Ragunath, G.

    2017-11-01

    In this paper a current fed interleaved DC - DC boost converter which has an isolated topology and used for high voltage step up is proposed. A basic DC to DC boost converter converts uncontrolled DC voltage into controlled DC voltage of higher magnitude. Whereas this topology has the advantages of lower input current ripple, lesser output voltage, lesser stress on switches, faster transient response, improved reliability and much lesser electromagnetic emission over the conventional DC to DC boost converter. Most important benefit of this interleaved DC to DC boost converter is much higher efficiency. The input current is divided into two paths, substantially ohmic loss (I2R) and inductor ac loss gets reduced and finally the system achieves much higher efficiency. With recent mandates on energy saving interleaved DC to DC boost converter may be used as a very powerful tool to maintain good power density keeping the input current manageable. Higher efficiency also allows higher switching frequency and as a result the topology becomes more compact and cost friendly. The proposed topology boosts 48v DC to 200 V DC. Switching frequency is 100 kHz and PSIM 9.1 Platform has been used for the simulation.

  11. ELECTRICAL PROPERTIES OF DC REACTIVE MAGNETRON ...

    African Journals Online (AJOL)

    Mgina

    ABSTRACT. Reactive direct current (DC) sputtered ZnO:Al films were prepared using the plasma emission monitoring (PEM) system. Films were deposited using PEM setpoints ranging from 50 to 80%. Transmittance and reflectance of the films were measured by using the UV-VIS-NIR Lambda 900 double beam ...

  12. Power Talk in DC Micro Grids

    DEFF Research Database (Denmark)

    Angjelichinoski, Marko; Stefanovic, Cedomir; Popovski, Petar

    2015-01-01

    level. In this paper, we consider power talk in a DC MG and introduce a channel model based on Thevenin equivalent. The result is a channel whose state that can be estimated by both the transmitter and the receiver. Using this model, we present design of symbol constellations of arbitrary order...

  13. DC-breaker for a thyristor inverter

    Energy Technology Data Exchange (ETDEWEB)

    Kuebart, G. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electrical Machines and Power Electronics

    1996-11-01

    It was shown that the dc-breaker works satisfactorily. Currents up to 90 A were turned off with the present test set-up in a sufficiently short time of about 3 ms. The theory and calculation rules, explained in this report, correspond with the measured results. 2 refs, 19 figs

  14. Manufacturing development of DC-10 advanced rudder

    Science.gov (United States)

    Cominsky, A.

    1979-01-01

    The design, manufacture, and ground test activities during development of production methods for an advanced composite rudder for the DC-10 transport aircraft are described. The advanced composite aft rudder is satisfactory for airline service and a cost saving in a full production manufacturing mode is anticipated.

  15. Space charge fields in DC cables

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson; Crichton, George C; Pedersen, Aage

    1996-01-01

    The space charge that accumulates in DC cables can, mathematically, be resolved into two components. One is related to the temperature and the other to the magnitude of the electric field strength. Analytical expressions for the electric fields arising from each of these space charge components...

  16. Electrical Anomalies Observed During DC3

    Science.gov (United States)

    Lang, Timothy J.; Rutledge, Steven A.; Dolan, Brenda; Krehbiel, Paul; Rison, William; Lindsey, Daniel T.; Lyons, Walt

    2013-01-01

    The primary scientific goals of DC3 involved improving our understanding of the chemical impacts of thunderstorms and their anvils. However, the Colorado domain provided opportunities to study other interesting phenomena, including the potential impacts of smoke ingestion on convection and thunderstorms, electrification processes in smoke plumes and pyrocumulonimbus clouds, and the production of sprites by unconventional thunderstorm.

  17. FUNCTIONAL CORRELATION OF FP AND DC METHODS

    Directory of Open Access Journals (Sweden)

    Marin Kaluža

    2013-02-01

    Full Text Available Most of organizations today use information-communication technologies (ICT for building an information system (IS. IS is assembled of hardware, software, network resources, organizational and human resources. In IS development process, complexity is crucial for evaluating quantities of resources needed (time, people, money, equipment. Complexity of an IS can be evaluated and/or measured in different phases of development. There are many methods for measuring complexity, but mostly used and thoroughly described method is Function Point Analysis (FP. The opposite method, Database Complexity (DC, does not measure all the aspects of IS, but it could evaluate system complexity depending on the database complexity. DC method is intended to be used for measuring semantic complexity of the IS database, and can be shown by counting attributes A and foreign keys F. This paper describes a very high correlation between FP and DC methods, and defines a function which can in 95% of accuracy express FP values from measured DC values.

  18. DC Electric Drive with Autonomous Power Supply

    Directory of Open Access Journals (Sweden)

    V. V. Ramanau

    2006-01-01

    Full Text Available The paper examines a circuit of an impulse DC electric drive with one controlled-rectifier that is a thyristor. Regulation of an average voltage value on an engine is carried out by changing frequency of controlling impulses applied to the thyristor. Calculation of commutating capacitance and inductance is given in the paper.

  19. New Logic Circuit with DC Parametric Excitation

    Science.gov (United States)

    Sugahara, Masanori; Kaneda, Hisayoshi

    1982-12-01

    It is shown that dc parametric excitation is possible in a circuit named JUDO, which is composed of two resistively-connected Josephson junctions. Simulation study proves that the circuit has large gain and properties suitable for the construction of small, high-speed logic circuits.

  20. Research of digital controlled DC/DC converter based on STC12C5410AD

    Science.gov (United States)

    Chen, Dan-Jiang; Jin, Xin; Xiao, Zhi-Hong

    2010-02-01

    In order to study application of digital control technology on DC/DC converter, principle of increment mode PID control algorithm was analyzed in the paper. Then, a SCM named STC12C5410AD was introduced with its internal resources and characteristics. The PID control algorithm can be implemented easily based on it. The output of PID control was used to change the value of a variable that is 255 times than duty cycle, and this reduced the error of calculation. The valid of the presented algorithm was verified by an experiment for a BUCK DC/DC converter. The experimental results indicated that output voltage of the BUCK converter is stable with low ripple.

  1. Washington DC Metropolitan Area Drug Study Homeless and Transient Population (DC-MADST-1991)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The DC Metropolitan Area Drug Study (DCMADS) was conducted in 1991, and included special analyses of homeless and transient populations and of women delivering live...

  2. Washington DC Metropolitan Area Drug Study Household and Non-Household Populations (DC-MADSH-1991)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The DC Metropolitan Area Drug Study (DCMADS) was conducted in 1991, and included special analyses of homeless and transient populations and of women delivering live...

  3. Differential Mode EMI Filter Design for Isolated DC-DC Boost Converter

    DEFF Research Database (Denmark)

    Makda, Ishtiyaq Ahmed; Nymand, Morten

    2014-01-01

    A Differential Mode EMI filter for a low input voltage high-current isolated dc-dc boost converter is designed and presented in this paper. The primary side Differential Mode noise voltage is low due to the high transformer turn ratio, however, the input current is very high and since the EMI limit...... also does not change for such converters, it requires greatly optimized design approach for the filter including the correct sizing of the filter components. A complete analytical filter design process is carried out such a way that the Differential Mode noise voltage source in the converter...... is identified first. The DM noise model is then established and based on the harmonic analysis of the noise source voltage waveform, the complete Differential Mode EMI filter, including the filter resonance damping branch, is designed for a 3kW isolated dc-dc boost converter. The noise model and its theoretical...

  4. A Nonlinear Digital Control Solution for a DC/DC Power Converter

    Science.gov (United States)

    Zhu, Minshao

    2002-01-01

    A digital Nonlinear Proportional-Integral-Derivative (NPID) control algorithm was proposed to control a 1-kW, PWM, DC/DC, switching power converter. The NPID methodology is introduced and a practical hardware control solution is obtained. The design of the controller was completed using Matlab (trademark) Simulink, while the hardware-in-the-loop testing was performed using both the dSPACE (trademark) rapid prototyping system, and a stand-alone Texas Instruments (trademark) Digital Signal Processor (DSP)-based system. The final Nonlinear digital control algorithm was implemented and tested using the ED408043-1 Westinghouse DC-DC switching power converter. The NPID test results are discussed and compared to the results of a standard Proportional-Integral (PI) controller.

  5. High Voltage Coil Current Sensor for DC-DC Converters Employing DDCC

    Directory of Open Access Journals (Sweden)

    M. Drinovsky

    2015-12-01

    Full Text Available Current sensor is an integral part of every switching converter. It is used for over-current protection, regulation and in case of multiphase converters for balancing. A new high voltage current sensor for coil-based current sensing in DC-DC converters is presented. The sensor employs DDCC with high voltage input stage and gain trimming. The circuit has been simulated and implemented in 0.35 um BCD technology as part of a multiphase DC-DC converter where its function has been verified. The circuit is able to sustain common mode voltage on the input up to 40 V, it occupies 0.387*0.345 mm2 and consumes 3.2 mW typically.

  6. Y-source impedance-network-based isolated boost DC/DC converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Town, Graham; Loh, Poh Chiang

    2014-01-01

    A dc-dc converter with very high voltage gain is proposed in this paper for any medium-power application requiring a high voltage boost with galvanic isolation. The proposed converter topology can be realized using only two switches. With this topology a very high voltage boost can be achieved even...... with a relatively low duty cycle of the switches, and the gain obtainable is presently not matched by any existing impedance network based converter operated at the same duty ratio. The proposed converter has a Y-source impedance network to boost the voltage at the intermediate dc-link side and a push......-pull transformer for square-wave AC inversion and isolation. The voltage-doubler rectifier provides a constant dc voltage at the output stage. A theoretical analysis of the converter is presented, supported by simulation and experimental results. A 250 W down-scaled prototype was implemented in the laboratory...

  7. LMI approach for sliding mode control and analysis of DC-DC converters

    Directory of Open Access Journals (Sweden)

    Lekić Aleksandra D.

    2016-01-01

    Full Text Available Circuits' and in particular DC/DC converters' switching behavior is analyzed in this paper using the equivalent control modeling of the dynamic systems' sliding mode regime. As a representative example and also being one of the0 most complex circuits among DC/DC converters, the Ćuk converter is chosen. It is shown how the converter's behavior in the steady state regime can be studied and analyzed by the linear matrix inequalities based stability conditions for linear dynamic systems with nonlinear sector bounded perturbations. The maximization of the nonlinear sector bound provides a limit for applying the linear ripple approximation in the converter operation analysis. Furthermore, our approach is validated by providing simulation results for two different switching surfaces of practical interest.

  8. Embedded Controlled Isolated Bidirectional Full-Bridge DC-DC Converter with Flyback Snubber

    Directory of Open Access Journals (Sweden)

    D. Kirubakaran

    2012-01-01

    Full Text Available An isolated bidirectional full-bridge DC-DC converter with flyback snubber for supplying a resistive load is simulated and experimentally verified. The DC-DC converter for high conversion ratio, high output power, and soft start-up capability is presented in this paper. The circuit consists of a capacitor, a diode, and a flyback converter. These components help to clamp the voltage spikes caused by the current difference between the current fed inductor and leakage inductance of the isolation transformer. The switches are operated by soft-switching technology. The suppression of inrush current which is usually found in the boost mode start-up transition is presented here. The simulated and experimental results for output voltage, output current, and power for both buck and boost modes are presented.

  9. Reliability-Oriented Optimization of the LC Filter Design of a Buck DC-DC Converter

    DEFF Research Database (Denmark)

    Liu, Yi; Huang, Meng; Wang, Huai

    2017-01-01

    Lifetime is an important performance factor in the reliable operation of power converters. However, the state-of-the-art LC filter design of a buck DC-DC converter is limited to the specifications of voltage and current ripples and constrains in power density and cost without reliability consider......Lifetime is an important performance factor in the reliable operation of power converters. However, the state-of-the-art LC filter design of a buck DC-DC converter is limited to the specifications of voltage and current ripples and constrains in power density and cost without reliability...... considerations. This paper proposes a method to optimize the design of the LC filters from a reliability perspective, besides other considerations. An enhanced model is derived to quantify the lifetime of the capacitor in the filter considering the electro-thermal stress on it. Furthermore, the influence...

  10. Integrated Three-Port DC-DC Converter for Photovoltaic (PV) Battery Stand-alone Systems

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Andersen, Michael A. E.

    2016-01-01

    Several power sources such as PV solar arrays and battery are often used to manage the power flow for a photovoltaic (PV) based stand-alone power system due to the fluctuation nature of solar energy resource, and deliver a continuous power to the users in an appropriate form. Traditionally, three...... of solar energy. Moreover, a novel transformer configuration enables variable turns ratio controlled by the phase between the two current excitations subjected to the primary windings, allowing a wider input/output range. 1 kW experimental prototype has been built to demonstrate a wellmanaged power flow...... different single-input single-output (SISO) dc/dc converters would have been used. To reduce the cost and improve the power density of the system, an integrated three-port isolated dc/dc converter is proposed in this paper. It can realize all functions of the energy delivery due to the fluctuation nature...

  11. Analysis of the Coupling Behavior of PEM Fuel Cells and DC-DC Converters

    Directory of Open Access Journals (Sweden)

    Achim Kienle

    2009-03-01

    Full Text Available The connection between PEM fuel cells and common DC-DC converters is examined. The analysis is model-based and done for boost, buck and buck-boost converters. In a first step, the effect of the converter ripples upon the PEM fuel cell is shown. They introduce oscillations in the fuel cell. Their appearance is explained, discussed and possibilities for their suppression are given. After that, the overall behaviors of the coupled fuel cell-converter systems are analyzed. It is shown, that neither stationary multiplicities nor oscillations can be introduced by the couplings and therefore separate control approaches for both the PEMFC and the DC-DC converters are applicable.

  12. Characterising and modelling extended conducted electromagnetic interference in densely packed DC-DC converter

    CSIR Research Space (South Africa)

    Grobler, Inus

    2013-09-01

    Full Text Available Extended Conducted Electromagnetic Interference in Densely Packed DC- DC Converter I Grobler1 and MN Gitau2 Department of Electrical, Electronic and Computer Engineering, University of Pretoria, South Africa. igrobler@csir.co.za1, mgitau.... This will improve the overall design efficiency and shorten the crucial time to market period [1]. It is of utmost importance to try and model the electromagnetic compatibility concurrent with the power processor design stage. The marketplace is in need...

  13. Sliding-mode control of single input multiple output DC-DC converter

    Science.gov (United States)

    Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang

    2016-10-01

    Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

  14. Kvasiresonant DC-DC Converter with Switching at Zero Current - Part 1

    OpenAIRE

    Vorel, P.

    1998-01-01

    A kvasiresonant DC - DC converter and its control circuits are proposed. The relations useful for design of the converter will be deduced in the part 2. The fundamental idea of the converter is the switching -on and -off a transistor at zero current. In this way the switching losses are eliminated. It enables to design a converter with a large output power (several kW), high switching frequency (about 200 kHz), very good efficiency and low radiation.

  15. Dynamic Performance Analyses of Current Sharing Control for DC/DC Converters

    OpenAIRE

    Sun, Juanjuan

    2007-01-01

    Paralleling operation of DC/DC converters is widely used in today's distributed power systems. To ensure balanced output currents among paralleled power modules, current sharing control is usually necessary.Active current sharing controls with current feedback mechanism are widely used in today's power supplies. However, the dynamic performance of these current sharing control schemes are not yet clearly explored. In this work, the dynamic current sharing performance is evaluated for parallel...

  16. Quasiperiodicity and Torus Breakdown in a Power Electronic DC/DC Converter

    DEFF Research Database (Denmark)

    Zhusubaliyev, Zhanybai; Soukhoterin, Evgeniy; Mosekilde, Erik

    2007-01-01

    This paper discusses the mechanisms of torus formation and torus destruction in a dc/dc converter with relay control and hysteresis. We establish a chart of the dynamical modes in the input voltage versus load resistance parameter plane. This chart displays several different torus bifurcations al......). Particular emphasis is paid to following the changes of the stable and unstable manifolds in detail. (c) 2006 Published by Elsevier B.V. on behalf of IMACS....

  17. Control of power flow in a resonant DC-DC buck and boost converter

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, I. [Technical Univ. of Budapest, Dept. of Automation, Budapest (Hungary)]|[Computer and Automation Inst., Hungarian Academy of Sciences (Hungary); Hamar, J. [Technical Univ. of Budapest, Dept. of Automation, Budapest (Hungary)

    2000-07-01

    The paper contains a detailed analysis of the steady-state operation of the dual channel resonant DC-DC step up/down converter. The limits of the real operation have been marked out and the regions of continuous conduction mode (CCM) and discontinuous conduction mode (DCM) have also been separated. Three kinds of power flow control methods are observed, but the application of combined strategy is also possible. (orig.)

  18. Sliding mode control of DC-to-DC power converters using integral reconstructors

    Energy Technology Data Exchange (ETDEWEB)

    Sira-Ramirez, H. [CINVESTAV-IPN, Departamento de Ingenieria Electrica, Mexico (Mexico); Marquez-Contreras, R. [CNRS, Gif-sur-Ivette (France). Lab. des Signaux et Systemes; Fliess, M. [Ecole Normale Superieure de Cachan (France). Centre de Mathematiques et Leurs Applications

    2002-07-01

    A sliding mode feedback controller, based on integral reconstructors is developed for the regulation of the 'boost' DC-to-DC power converter circuit conduction in continuous conduction mode. The feedback control scheme uses only output capacitor voltage measurements, as well as knowledge of the available input signal, represented by the switch positions. The robustness of the feedback scheme is tested with abusively large, unmodelled, sudden load resistance variations. (Author)

  19. A DC-DC Converter Efficiency Model for System Level Analysis in Ultra Low Power Applications

    Directory of Open Access Journals (Sweden)

    Benton H. Calhoun

    2013-06-01

    Full Text Available This paper presents a model of inductor based DC-DC converters that can be used to study the impact of power management techniques such as dynamic voltage and frequency scaling (DVFS. System level power models of low power systems on chip (SoCs and power management strategies cannot be correctly established without accounting for the associated overhead related to the DC-DC converters that provide regulated power to the system. The proposed model accurately predicts the efficiency of inductor based DC-DC converters with varying topologies and control schemes across a range of output voltage and current loads. It also accounts for the energy and timing overhead associated with the change in the operating condition of the regulator. Since modern SoCs employ power management techniques that vary the voltage and current loads seen by the converter, accurate modeling of the impact on the converter efficiency becomes critical. We use this model to compute the overall cost of two power distribution strategies for a SoC with multiple voltage islands. The proposed model helps us to obtain the energy benefits of a power management technique and can also be used as a basis for comparison between power management techniques or as a tool for design space exploration early in a SoC design cycle.

  20. Design and implementation of current fed DC-DC converter for PHEV application using renewable source

    Science.gov (United States)

    Milind Metha, Manish; Tutki, Sanjay; Rajan, Aju; Elangovan, D.; Arunkumar, G.

    2017-11-01

    As the fossil fuels are depleting day by day, the use of renewable energy sources came into existence and they evolved a lot lately. To increase efficiency and productivity in the hybrid vehicles, the existence less efficient petroleum and diesel IC engines need to be replaced with the new and efficient converters with renewable energy sources. This has to be done in such a way that impacts three factors mainly: cost, efficiency and reliability. The PHEVs that have been launched and the upcoming PHEVs using converters with voltage range around 380V to 400V generated with power ranges between 2.4KW to 2.8KW. The basic motto of this paper is to design a prolific converter while considering the factor such as cost and size. In this paper, a two stage DC-DC converter is proposed and the proposed DC-DC converter is utilized to endeavour voltage from 24V (photovoltaic source) to a yield voltage of 400V and to meet the power demand of 250W, since only one panel is being used for this proposed paper. This paper discuss in detail about why and how the current fed DC-DC converter is utilized along with a voltage doubler, thus reducing transformer turns and thereby reducing overall size of the product. Simulation and hardware results have been presented along with calculations for duty cycle required for firing sequence for different values of transformer turns.

  1. CAMEX-4 DC-8 DROPSONDE SYSTEM V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The CAMEX-4 DC-8 Dropsonde System dataset was collected by the DC-8 Dropsonde System (D8D) uses dropwindsonde and Global Positioning System (GPS) receivers to...

  2. Brushless dc motor uses electron beam switching tube as commutator

    Science.gov (United States)

    Studer, P.

    1965-01-01

    Electron beam switching tube eliminates physical contact between rotor and stator in brushless dc motor. The tube and associated circuitry control the output of a dc source to sequentially energize the motor stator windings.

  3. Three Phase Resonant DC Power Converter for Ion Thrusters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Our phase 1 study has revealed many significant benefits of a new class of DC-to-DC power converters with performance that cannot be matched by current flight power...

  4. GPM Ground Validation Navigation Data DC-8 OLYMPEX V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation NASA DC-8 Navigation Data OLYMPEX dataset supplies navigation data collected by the NASA DC-8 aircraft for flights that occurred during...

  5. Trends and determinants of cycling in the Washington, DC region.

    Science.gov (United States)

    2011-01-01

    This report analyzes cycling trends, policies, and commuting in the Washington, DC area. The analysis is divided into two parts. : Part 1 focuses on cycling trends and policies in Washington (DC), Alexandria (VA), Arlington County (VA), Fairfax Count...

  6. Pemodelan Sistem Kontrol Motor DC Dengan Temperatur Udara Sebagai Pemicu

    OpenAIRE

    Prabowo, Brilliant Adhi

    2008-01-01

    Motor dc lebih sering digunakan untuk beberapa kegiatan yang memerlukan pengaturan kecepatan daripada motor ac. Disamping pengontrolan kecepatan putar, sistem control motor dc juga mengatur arah putar rotor, searah jarum jam atau berlawanan dengan arah jarum jam. Salah satu sistem control motor dc adalah menggunakan Modulasi Lebar Pulsa (PWM) sebagai pemicu pada driver control seperti transistor H-Bridge. Penelitian ini bertujuan untuk merancang sistem control motor dc menggunakan suhu udar...

  7. DC-DC Type High-Frequency Link DC for Improved Power Quality of Cascaded Multilevel Inverter

    Science.gov (United States)

    Sadikin, Muhammad; Senjyu, Tomonobu; Yona, Atsushi

    2013-06-01

    Multilevel inverters are emerging as a new breed of power converter options for power system applications. Recent advances in power switching devices enabled the suitability of multilevel inverters for high voltage and high power applications because they are connecting several devices in series without the need of component matching. Usually, a transformerless battery energy storage system, based on a cascaded multilevel inverter, is used as a measure for voltage and frequency deviations. System can be reduced in size, weight, and cost of energy storage system. High-frequency link circuit topology is advantageous in realizing compact and light-weight power converters for uninterruptible power supply systems, new energy systems using photovoltaic-cells, fuel-cells and so on. This paper presents a DC-DC type high-frequency link DC (HFLDC) cascaded multilevel inverter. Each converter cell is implemented a control strategy for two H-bridge inverters that are controlled with the same multicarrier pulse width modulation (PWM) technique. The proposed cascaded multilevel inverter generates lower voltage total harmonic distortion (THD) in comparison with conventional cascaded multilevel inverter. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of the proposed cascaded multilevel inverter.

  8. Antimicrobial Effects of Three Tropical Plant Extracts on Staphylococcus Aureus, Escherichia Coli and Candida Albicans

    OpenAIRE

    R. N. Okigbo; Mmeka, E C

    2008-01-01

    Antimicrobial activities of the leaf extracts of Cymbopogon citatrus (lemongrass) and Vernonia amygdalina (bitter leaf) and the seed extracts of Garcinia kola (bitter kola) were carried out. G. kola had effect only on Staphyococcus aureus and Escherichia coli with no inhibition on Candida albicans. Ethanol, cold water and hot water extracts of Vernonia amygdalina and Cymbopogon citratus showed inhibition on the three organism but G. kola ethanol, cold water and hot water extracts only inhibit...

  9. Efficacité des huiles essentielles de trois plantes aromatiques contre ...

    African Journals Online (AJOL)

    Objectif : La présente étude vise à évaluer l'activité antimicrobienne des huiles essentielles extraites des feuilles fraîches de Cymbopogon citratus (L.), de Cymbopogon nardus (L.), et de Eucalyptus saligna (S.), sur les moisissures isolées des stocks de niébé de quelques magasins de vente du sud-Bénin. Méthodologie et ...

  10. Meyer–Neldel DC conduction in chalcogenide glasses

    Indian Academy of Sciences (India)

    Abstract. Meyer–Neldel (MN) formula for DC conductivity (σDC) of chalcogenide glasses is obtained using extended pair model and random free energy barriers. The integral equations for DC hopping conductivity and external conductance are solved by iterative procedure. It is found that. MN energy ( EMN) originates from ...

  11. Construction and evaluation of rats' tolerogenic dendritic cells (DC ...

    African Journals Online (AJOL)

    The following methods were employed to phenotype DC: 1) Observation of cell morphology; 2) Evaluation of cell viability using trypan blue staining; 3) Purity determination of DC through detection of specific markers OX-62; 4) Evaluation of mature state of DC via the determination of the expression of CD80 and CD86; ...

  12. Hierarchical Control for Multiple DC-Microgrids Clusters

    DEFF Research Database (Denmark)

    Shafiee, Qobad; Dragicevic, Tomislav; Vasquez, Juan Carlos

    2014-01-01

    DC microgrids (MGs) have gained research interest during the recent years because of many potential advantages as compared to the ac system. To ensure reliable operation of a low-voltage dc MG as well as its intelligent operation with the other DC MGs, a hierarchical control is proposed in this p...

  13. Cost-based droop scheme for DC microgrid

    DEFF Research Database (Denmark)

    Nutkani, Inam Ullah; Wang, Peng; Loh, Poh Chiang

    2014-01-01

    DC microgrids are gaining interest due to higher efficiencies of DC distribution compared with AC. The benefits of DC systems have been widely researched for data centers, IT facilities and residential applications. The research focus, however, has been more on system architecture and optimal vol...

  14. Overvoltage protection in DC power systems; Ueberspannungsschutz in Gleichstromanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Birkl, Josef; Zahlmann, Peter [Dehn + Soehne GmbH + Co.KG, Neumarkt (Germany)

    2012-02-15

    The utilisation of DC power systems has increased dramatically in the recent years. In addition to traditional DC applications such as in telecommunications and railway engineering a variety of DC applications arise due to a rapid spread of photovoltaic systems. Current projects for the e-mobility expand the scope of application.

  15. All Digital Switch-Mode DC/DC Converters with BIST Functionality for Harsh Space Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Space Micro ?Arizona State University (ASU) team will develop an all-digitally controlled, wide temperature range point-of-load switch-mode DC-DC regulator core...

  16. On the modelling of linear-assisted DC-DC voltage regulators for photovoltaic solar energy systems

    Science.gov (United States)

    Martínez-García, Herminio; García-Vílchez, Encarna

    2017-11-01

    This paper shows the modelling of linear-assisted or hybrid (linear & switching) DC/DC voltage regulators. In this kind of regulators, an auxiliary linear regulator is used, which objective is to cancel the ripple at the output voltage and provide fast responses for load variations. On the other hand, a switching DC/DC converter, connected in parallel with the linear regulator, allows to supply almost the whole output current demanded by the load. The objective of this topology is to take advantage of the suitable regulation characteristics that series linear voltage regulators have, but almost achieving the high efficiency that switching DC/DC converters provide. Linear-assisted DC/DC regulators are feedback systems with potential instability. Therefore, their modelling is mandatory in order to obtain design guidelines and assure stability of the implemented power supply system.

  17. DC-Voltage Fluctuation Elimination Through a DC-Capacitor Current Control for DFIG Converters Under Unbalanced Grid Voltage Conditions

    DEFF Research Database (Denmark)

    Liu, Changjin; Xu, Dehong; Zhu, Nan

    2013-01-01

    Unbalanced grid voltage causes a large second-order harmonic current in the dc-link capacitors as well as dc-voltage fluctuation, which potentially will degrade the lifespan and reliability of the capacitors in voltage source converters. This paper proposes a novel dc-capacitor current control...... method for a grid-side converter (GSC) to eliminate the negative impact of unbalanced grid voltage on the dc-capacitors. In this method, a dc-capacitor current control loop, where a negative-sequence resonant controller is used to increase the loop gain, is added to the conventional GSC current control...... loop. The rejection capability to the unbalanced grid voltage and the stability of the proposed control system are discussed. The second-order harmonic current in the dc capacitor as well as dc-voltage fluctuation is very well eliminated. Hence, the dc capacitors will be more reliable under unbalanced...

  18. First Implementation of a Two-Stage DC-DC Conversion Powering Scheme for the CMS Phase-2 Outer Tracker

    CERN Document Server

    Feld, Lutz Werner; Karpinski, Waclaw; Klein, Katja; Lipinski, Martin; Pauls, Alexander Josef; Preuten, Marius; Rauch, Max Philip; Wangelik, Frederik; Wlochal, Michael

    2017-01-01

    The 2S silicon strip modules for the CMS Phase-2 tracker upgrade will require two operating voltages. These will be provided via a two-step DC-DC conversion powering scheme, in which one DC-DC converter delivers 2.5\\,V while the second DC-DC converter receives 2.5\\,V at its input and converts it to 1.2\\,V. The DC-DC converters will be mounted on a flex PCB, the service hybrid, together with an opto-electrical converter module (VTRx+) and a serializer (LP-GBT). The service hybrid will be mounted directly on the 2S module. A prototype service hybrid has been developed and its performance has been evaluated, including radiative and conductive noise emissions, and efficiency. In addition system tests with a prototype module have been performed. In this report the service hybrid will be described and the test results will be summarized.

  19. DC Proximal Newton for Nonconvex Optimization Problems.

    Science.gov (United States)

    Rakotomamonjy, Alain; Flamary, Rémi; Gasso, Gilles

    2016-03-01

    We introduce a novel algorithm for solving learning problems where both the loss function and the regularizer are nonconvex but belong to the class of difference of convex (DC) functions. Our contribution is a new general purpose proximal Newton algorithm that is able to deal with such a situation. The algorithm consists in obtaining a descent direction from an approximation of the loss function and then in performing a line search to ensure a sufficient descent. A theoretical analysis is provided showing that the iterates of the proposed algorithm admit as limit points stationary points of the DC objective function. Numerical experiments show that our approach is more efficient than the current state of the art for a problem with a convex loss function and a nonconvex regularizer. We have also illustrated the benefit of our algorithm in high-dimensional transductive learning problem where both the loss function and regularizers are nonconvex.

  20. Universality of DC electrical conductivity from holography

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Xian-Hui, E-mail: gexh@shu.edu.cn [Shanghai Key Laboratory of High Temperature Superconductors, Department of Physics, Shanghai University, Shanghai, 200444 (China); Department of Physics, University of California, San Diego, CA92122 (United States); Sin, Sang-Jin, E-mail: sjsin@hangyang.ac.kr [Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of); Wu, Shao-Feng, E-mail: sfwu@shu.edu.cn [Department of Physics, Shanghai University, Shanghai, 200444 (China)

    2017-04-10

    We propose a universal formula of dc electrical conductivity in rotational- and translational-symmetries breaking systems via the holographic duality. This formula states that the ratio of the determinant of the dc electrical conductivities along any spatial directions to the black hole area density in zero-charge limit has a universal value. As explicit illustrations, we give several examples elucidating the validation of this formula: We construct an anisotropic black brane solution, which yields linear in temperature for the in-plane resistivity and insulating behavior for the out-of-plane resistivity; We also construct a spatially isotropic black brane solution that both the linear-T and quadratic-T contributions to the resistivity can be realized.

  1. DC breakdown experiments with cobalt electrodes

    CERN Document Server

    Descoeudres, Antoine; Nordlund, Kai

    2009-01-01

    RF accelerating structures of the Compact Linear Collider (CLIC) require a material capable of sustaining high electric field with a low breakdown rate and low induced damage. Because of the similarity of many aspects of DC and RF breakdown, a DC breakdown study is underway at CERN in order to test candidate materials and surface preparations, and have a better understanding of the breakdown mechanism under ultra-high vacuum in a simple setup. The conditioning speed, breakdown field and field enhancement factor of cobalt have been measured. The average breakdown field after conditioning reaches 615 MV/m, which places cobalt amongst the best materials tested so far. By comparison with results and properties of other metals, the high breakdown field of Co could be due to its high work function and maybe also to its hexagonal crystal structure. Geneva, Switzerland (June 2009) CLIC – Note – 875

  2. Research on Two-channel Interleaved Two-stage Paralleled Buck DC-DC Converter for Plasma Cutting Power Supply

    DEFF Research Database (Denmark)

    Yang, Xi-jun; Qu, Hao; Yao, Chen

    2014-01-01

    As for high power plasma power supply, due to high efficiency and flexibility, multi-channel interleaved multi-stage paralleled Buck DC-DC Converter becomes the first choice. In the paper, two-channel interleaved two- stage paralleled Buck DC-DC Converter powered by three-phase AC power supply is...... and the use of phase-shift driving technology and current sharing technology....

  3. 77 FR 39921 - D&C Red No. 6 and D&C Red No. 7; Change in Specification

    Science.gov (United States)

    2012-07-06

    ... HUMAN SERVICES Food and Drug Administration 21 CFR Part 74 D&C Red No. 6 and D&C Red No. 7; Change in... Administration (FDA or the Agency) is revising its requirements for D&C Red No. 6 and D&C Red No. 7 by replacing.... ADDRESSES: You may submit objections and requests for a hearing, identified by Docket No. FDA-2011-C-0050...

  4. Engine bleed air reduction in DC-10

    Science.gov (United States)

    Newman, W. H.; Viele, M. R.

    1980-01-01

    An 0.8 percent fuel savings was achieved by a reduction in engine bleed air through the use of cabin air recirculation. The recirculation system was evaluated in revenue service on a DC-10. The cabin remained comfortable with reductions in cabin fresh air (engine bleed air) as much as 50 percent. Flight test verified the predicted fuel saving of 0.8 percent.

  5. AC-DC Power Processor, Type I.

    Science.gov (United States)

    1979-11-01

    output vol taqv S ice the out put rectifiers drop is a 1 arqe percentaote of the output voltate value. F i ure 24 Ows5 the out put impedance of the AC-I)C...65- TABLE XII- AC-DC POWER PROCESSOR TEMPERATURE PROFILE AT 83"F AMBIENT (COMPONENT AND UNIT TEMPERATURES AT END OF 72 HOUR TESI ) T.C. NO. LOCATION

  6. Practical dc SQUID system: Devices and electronics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guofeng [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ (Germany); Zhang, Yi, E-mail: y.zhang@fz-juelich.de [Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich (FZJ), D-52425 Jülich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ (Germany); Hong, Tao; Wang, Hai [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ (Germany); University of Chinese Academy of Sciences, Beijing 100049 (China); Krause, Hans-Joachim [Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich (FZJ), D-52425 Jülich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ (Germany); Xie, Xiaoming [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ (Germany)

    2015-11-15

    Highlights: • The current noise contribution in direct readout scheme for dc SQUID was analyzed. • A current feedback circuit for suppressing the current noise was introduced. • Two criteria to measure the suppression factor were introduced. • A practical SQUID system with acceptable noise performance was suggested. - Abstract: In order to set up a liquid helium-cooled practical dc SQUID system with acceptable noise figure, we employ a weakly damped dc SQUID with a large flux-to-voltage transfer coefficient ∂V/∂Φ in a direct readout scheme (DRS) without flux modulation. Two preamplifiers are utilized: (1) AD 797 for a so-called “single chip readout electronics” (SCRE); (2) 6 parallel-connected bipolar transistors (PCBT). The latter reduces the preamplifier voltage noise V{sub n} but increases its current noise I{sub n}, which plays a leading role in the system low-frequency noise. We introduce a current feedback circuit (CFC) consisting of an inductor L{sub i} coupled to the SQUID with mutual inductance M{sub i} to improve the noise performance. In this work, the preamplifier I{sub n} contribution and CFC are analyzed. To evaluate the I{sub n} suppression with CFC, two criteria are presented. Furthermore, we establish a dimensionless parameter ξ to describe CFC quantitatively. The system noise is compared with and without CFC using the two preamplifiers. For a dc SQUID with a loop inductance of 350 pH, an intrinsic noise of about 5 μΦ{sub 0}/√Hz and a corner frequency at 2 Hz are measured using PCBT with CFC.

  7. Marvel and DC Characters Inspired by Arachnids

    Directory of Open Access Journals (Sweden)

    Elidiomar Ribeiro Da-Silva

    2014-12-01

    Full Text Available This article compares arachnid-based Marvel and DC comics characters. The composition of a comic book character often has interesting ‘real-life’ influences. Given the strong connection between arachnids (especially spiders, scorpions and mites, all belonging to the zoological class 'Arachnida' and human beings it is not surprising that they have inspired many fictional characters. We recorded 84 Marvel Comics characters and 40 DC Comics characters, detailed in the dataset that accompanies the article (Da-Silva 2014. Most characters have been created recently, since the 1990s. Marvel has significantly more arachnid characters than DC. As for taxonomic classification, the characters were based mostly on spiders (zoological order 'Araneae'. Of the total characters, the majority are human beings, but an overwhelming number have at least some typical arachnid features. Villains (60.91% of total are significantly more numerous, considering the sum of the two publishers. Arachnids have bad reputation for being dangerous (Thorp and Woodson 1976; Ruppert and Barnes 1996. Since the public usually considers spiders, scorpions and mites “harmful” in general, we expected a larger contingent of villains. However, there was no statistical difference between the amount of villains and heroes in Marvel characters. It did not happen probably due to the success of one character: the Amazing Spider-Man.

  8. Proliferating effect of radiolytically depolymerized carrageenan on physiological attributes, plant water relation parameters, essential oil production and active constituents of Cymbopogon flexuosus Steud. under drought stress.

    Directory of Open Access Journals (Sweden)

    Minu Singh

    Full Text Available Carrageenan has been proved as potent growth promoting substance in its depolymerized form. However, relatively little is known about its role in counteracting the adverse effects of drought stress on plants. In a pot experiment, lemongrass (Cymbopogon flexuosus Steud., grown under different water stress regimes [(100% field capacity (FC, 80% FC and 60% FC], was sprayed with 40, 80 and 120 mg L-1 of gamma irradiated carrageenan (ICA. Foliar application of ICA mitigated the harmful effects of drought stress to various extents and improved the biochemical characteristics, quality attributes and active constituents (citral and geraniol of lemongrass significantly. Among the applied treatments, ICA-80 mg L-1 proved the best in alleviating detrimental effects of drought. However, drought stress (80 and 60% FC, irrespective of the growth stages, had an adverse impact on most of the studied attributes. Generally, 60% FC proved more deleterious than 80% FC. At 80% FC, application of ICA-80 mg L-1 elevated the essential oil (EO content by 18.9 and 25%, citral content by 7.33 and 8.19% and geraniol content by 9.2 and 8.9% at 90 and 120 days after planting (DAP, respectively, as compared to the deionized-water (DW spray treatment (80% FC+ DW. Whereas, at 60% FC, foliar application of 80 mg L-1 ICA significantly augmented the EO content by 15.4 and 17.8% and active constituents viz. citral and geraniol, by 5.01 and 5.62% and by 6.06 and 5.61% at 90 and 120 DAP, respectively, as compared to the control (water-spray treatment.

  9. Anti-inflammatory activity of the essential oils of Cymbopogon validus (Stapf) Stapf ex Burtt Davy from Eastern Cape, South Africa.

    Science.gov (United States)

    Rungqu, Pamela; Oyedeji, Opeoluwa; Nkeh-Chungag, Benedicta; Songca, Sandile; Oluwafemi, Oluwatobi; Oyedeji, Adebola

    2016-05-01

    To evaluate the essential oil composition and the anti-inflammatory activity of Cymbopogon validus (C. validus) leaves and flowers. A total of 300 g of fresh or dry (leaves and flowers) of C. validus were cut into small pieces and subjected to hydro-distillation method for approximately 5 h using the Clevenger apparatus. The extracted essential oils were then used for testing the anti-inflammatory activity. The anti-inflammatory activity was evaluated by using egg albumin-induced paw edema. The extracted oils had the following yields 2.2% for fresh leaves, 2.0% for dry leaves and 2.4% v/w for dry flowers. GC-MS results revealed that the oils contained artemisia ketone (37.5%), linalool (3.2%-29.6%), northujane (4.4%-16.8%), verbenone (13.5%), naphthalene (1.7%-9.6%), δ-cadinene (0.5%-8.1%), hedycaryol (5.4%-7.6%) and α-eudesmol (6.5%-6.7%) as the major constituents. C. validus essential oils showed significant (P < 0.05) anti-inflammatory effects from the first 30 min after albumin injection compared to aspirin which had a later onset of effect. The findings of this study show that the essential oil extracted from C. validus fresh or dry leaves and flowers have anti-inflammatory properties; that might be associated with the major components and the minor components found in the essential oils. Copyright © 2016 Hainan Medical College. Production and hosting by Elsevier B.V. All rights reserved.

  10. Avaliação do teor e composição do óleo essencial de Cymbopogon nardus (L. em diferentes épocas de colheita Evaluation of content and composition of the essential oil of Cymbopogon nardus (L. in different harvest times

    Directory of Open Access Journals (Sweden)

    Henrique Guilhon de Castro

    2010-06-01

    Full Text Available Este trabalho objetivou analisar o teor e a composição do óleo essencial do Cymbopogon nardus, em cinco épocas de colheita no Estado do Tocantins. As colheitas foram realizadas em cinco épocas em intervalos regulares de 28 dias, sendo a primeira aos 56 dias e a última aos 168 dias após transplante. A extração do óleo essencial foi realizada por hidrodestilação e a identificação dos componentes por CG e CG/EM. Os maiores teores de óleo essencial foram obtidos na segunda época de colheita (1,10% e na última época de colheita (1,07%. Foram identificados vinte e três compostos químicos no óleo essencial. Os monoterpenos identificados foram: limoneno, linalol, isopulegol, citronelal, citronelol, neral, geraniol, acetato de citronelol e acetato de geraniol. Os sesquiterpenos identificados foram: beta-elemeno, germacreno, alfa-muroleno, gama-cadineno, delta-cadineno, elemol, germacreno D-4-OL, óxido de cariofileno, tau-cadinol, beta-eudesmol e alfa-eudesmol. Os compostos majoritários do óleo essencial foram o citronelol, o geraniol e o elemol.This study aimed to analyze the content and the composition of the essential oil of Cymbopogon nardus in five harvest times in Tocantins State. Five harvesting were carried out in regular space of 28 days, the first in 56 days and the last in 168 days after transplanting. The essential oil was obtained by hydro distillation and the identification of the oil components by GC and GC/MS. The highest contents of the essential oil were obtained in the second harvest time (1.15% and in the last harvest time (1.07%. Twenty three chemical compounds were identified in the essential oil. The monoterpenes identified were: limonene, linalool, isopulegol, citronellal, citronellol, neral, geraniol, citronellol acetate and geraniol acetate. The sesquiterpenes identified were: beta-elemene, germacrene, alpha-muurolene, gamma-cadinene, delta-cadinene, elemol, germacrene D-4-OL, caryophyllene oxide, tau

  11. Viabilidade de sementes de feijão caupi após o tratamento com óleo essencial de citronela (Cymbopogon winterianus Jowitt Viability of Vigna unguiculata bean seeds treated with essential oil of Java grass (Cymbopogon winterianus Jowitt

    Directory of Open Access Journals (Sweden)

    M.V.A. Xavier

    2012-01-01

    Full Text Available O tratamento de sementes com óleos essenciais é um método alternativo que auxilia o manejo integrado de pragas. O objetivo deste trabalho foi avaliar a influência do tratamento de sementes de feijão Vigna unguiculata (L. Walp. com o óleo essencial de citronela (Cymbopogon winterianus Jowitt. Foi avaliado o efeito do óleo essencial de C. winterianus sobre V. unguiculata nas dosagens 20 μL, 15 μL, 10 μL, 5 μL e testemunha. A qualidade fisiológica das sementes foi determinada pela porcentagem de emergência, velocidade de emergência e índice de velocidade de emergência. A análise dos dados foi realizada no delineamento inteiramente casualizado, disposto em esquema fatorial 5 x 2 com cinco repetições. As sementes fumigadas apresentaram diferenças estatísticas entre os parâmetros avaliados em relação à testemunha. O óleo essencial de citronela revelou potencialidade alelopática sobre a germinação de sementes de feijão que variou de acordo com a concentração do óleo.Seed treatment with essential oils is an alternative method tool in integrated pest management. The objective of this study was to evaluate the effect of treating Vigna unguiculata (L. Walp. bean seeds with essential oil of Java grass (Cymbopogon winterianus Jowitt. The effect of C. winterianus essential oil on P. vulgaris was evaluated at levels of 20 μL, 15 μL, 10 μL, 5 μL and control. The physiologic quality of the seeds was determined by percentage emergence, speed emergence and speed emergence index. The data analysis was carried out using an entirely randomized design, in a 5 x 2 factorial scheme with five repetitions. The fumigated bean seeds showed the statistics differences among the analyzed parameters when was compared with the no treated check. The essential oil of Java grass revealed allelopathic potentiality on bean seed germination which varied according to the oil concentration.

  12. An FPGA Based Controller for a SOFC DC-DC Power System

    Directory of Open Access Journals (Sweden)

    Kanhu Charan Bhuyan

    2013-01-01

    Full Text Available Fuel cells are an attractive option for alternative power and of use in a variety of applications. This paper proposes a state space model for the solid oxide fuel cell (SOFC based power system that comprises fuel cell, DC-DC buck converter, and load. In this investigation we have taken up a case study for SOFC feeding a DC load where a DC-DC buck converter acts as the interface between the load and the source. A proportional-integral (PI controller is used in conjunction with pulse width modulation (PWM that computes the pulse width and switches the MOSFET at the right instant so that the desired voltage is obtained. The proposed model is validated through extensive simulation using MATLAB/SIMULINK. Controller for the fuel cell power system (FCPS is prototyped using XC3S500E development board containing a SPARTAN 3E Xilinx FPGA that simplifies the entire control circuit besides providing additional flexibility for further improvement. The results clearly indicate improved performance and validate our proposed model.

  13. DC-PLC Modem design for PV module monitoring

    Directory of Open Access Journals (Sweden)

    Seong-Duc Ma

    2016-01-01

    Full Text Available Nowadays, power line communication (PLC is a very efficient technique in cost aspect because it is communication system using power line without extra communication cables. In case of DC-PLC, it send a communication signal of the high frequency band to the monitoring system through the DC power line and is widely used for DC grid or the distributed generation system using DC source. Especially, the management system which evaluates the performance and efficiency of PV module by measuring PV power through monitoring system based on the DC-PLC has been increased. In this paper, apply the DC-PLC method for low cost PV module monitoring system and constitutes a measuring device and communication modem on a MCU. For the communication performance, we use the digital filter and apply the multi-carrier communication. The proposed DC-PLC Modem is verified through simulation and experiment.

  14. Design of current source DC/DC converter and inverter for 2kW fuel cell application

    DEFF Research Database (Denmark)

    Andreiciks, A.; Steiks, I.; Krievs, O.

    2013-01-01

    In order to use hydrogen fuel cell in domestic applications either as main power supply or backup power source, the low DC output voltage of the fuel cell has to be matched to the voltage level and frequency of the utility grid AC voltage. The interfacing power converter systems usually consist...... of a DC/DC converter and an inverter. In this paper a detailed simulation study of such interfacing converter system comprising a double inductor push-pull step-up DC/DC converter and a cascaded H-bridge inverter has been carried out and further confirmed with experimental results. The power converter...

  15. New topology for DC/DC bidirectional converter for hybrid systems in renewable energy

    Science.gov (United States)

    Lopez, Juan Carlos; Ortega, Manuel; Jurado, Francisco

    2015-03-01

    This article presents a new isolated DC/DC bidirectional converter with soft switching, using a transformer with two voltage taps and two full bridges with insulated-gate bipolar transistors (IGBTs), one on each side of the transformer to be integrated in hybrid systems of renewable energy. A large voltage conversion ratio can be achieved using this converter, in buck and booster modes. Also medium and high DC power can be converted with a good efficiency. Analysis and switching techniques have been reported. To verify the principle of operation, a laboratory prototype of 10 kW has been performed. Experimental results are presented, operating in boost mode. The switching algorithm used has been modelled in MATLAB-Simulink to generate C code. This code has been implemented in a DSP F2812, which has been used to build the prototype.

  16. High-voltage boost quasi-Z-source isolated DC/DC converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    A high-voltage gain two-switch quasi-Z-source isolated DC/DC converter has been presented in this study. It consists of a quasi-Z-source network at its input, a push-pull square-wave inverter at its middle, and a voltage-doubler rectifier at its output. When coordinated appropriately, the new...... converter uses less switches, a smaller common duty cycle and less turns for the transformer when compared with existing topologies. Its size and weight are therefore smaller, whereas its efficiency is higher. It is therefore well-suited for applications, where a wide range of voltage gain is required like...... renewable energy systems, DC power supplies found in telecom, aerospace and electric vehicles. To demonstrate the performance of the proposed converter, a 400 V, 500 W prototype has been implemented in the laboratory. Efficiency of the prototype measured is found to vary from 89.0 to 97.4% when its input...

  17. Multi-output DC-DC converters based on diode-clamped converters configuration

    DEFF Research Database (Denmark)

    Nami, A.; Zare, F.; Ghosh, A.

    2010-01-01

    for a diode-clamed inverter in the grid connection systems, where boosting low rectified output-voltage and series DC link capacitors is required. To verify the proposed topology, steady-state and dynamic analyses of a MOB converter are examined. A simple control strategy has been proposed to demonstrate......This study presents a new DC DC multi-output boost (MOB) converter which can share its total output between different series of output voltages for low- and high-power applications. This configuration can be utilised instead of several single output power supplies. This is a compatible topology...... the performance of the proposed topology for a double-output boost converter. The topology and its control strategy can easily be extended to offer multiple outputs. Simulation and experimental results are presented to show the validity of the control strategy for the proposed converter....

  18. Integrating DC/DC Conversion with Possible Reconfiguration within Submodule Solar Photovoltaic Systems

    Science.gov (United States)

    Huang, Peter Jen-Hung

    This research first proposes a method to merge photovoltaic (PV) cells or PV panels within the internal components DC-DC converters. The purpose of this merged structure is to reconfigure the PV modules between series and parallel connections using high switching frequencies (hundreds of kHz). This leads to multi-levels of voltages and currents that become applied to the output filter of the converter. Further, this research introduces a concept of a switching cell that utilizes the reconfiguration of series and parallel connections in DC-DC converters. The switching occurs at high switching frequency and the switches can be integrated to be within the solar panels or in between the solar cells. The concept is generalized and applied to basic buck and boost topologies. As examples of the new types of converters: reconfigurable PV-buck and PV-boost converter topologies are presented. It is also possible to create other reconfigurable power converters: non-isolated and isolated topologies. Analysis, simulation and experimental verification for the reconfigurable PV-buck and PV-boost converters are presented extensively to illustrate proof of concept. Benefits and drawbacks of the new approach are discussed. The second part of this research proposes to utilize the internal solar cell capacitance and internal solar module wire parasitic inductances to replace the input capacitor and filter inductor in boost derived DC-DC converters for energy harvesting applications. High switching frequency (MHz) hard switched and resonant boost converters are proposed. Their analysis, simulation and experimental prototypes are presented. A specific proof-of-concept application is especially tested for foldable PV panels, which are known for their high internal wire inductance. The experimental converters successfully boost solar module voltage without adding any external input capacitance or filter inductor. Benefits and drawbacks of new proposed PV submodule integrated boost

  19. Comparison of two different high performance mixed signal controllers for DC/DC converters

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes; Andersen, Michael Andreas E.

    2006-01-01

    an engineer experienced in microcontroller programming write the software algorithms to achieve optimal performance. Two mixed signal controller designs based on the same 8-bit microcontroller are compared both theoretically and experimentally. A 16-bit PID compensator with a sampling frequency of 200 k......This paper describes how mixed signal controllers combining a cheap microcontroller with a simple analogue circuit can offer high performance digital control for DC/DC converters. Mixed signal controllers have the same versatility and performance as DSP based controllers. It is important to have...

  20. Optimal Design and Tradeoffs Analysis for Planar Transformer in High Power DC-DC Converters

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2010-01-01

    A planar magnetic is a low profile transformer or inductor utilizing planar windings instead of the traditional windings made of Cu-wires. In this paper, the important factors for planar transformer design including winding loss, core loss, leakage inductance and stray capacitance have been.......2-kW full-bridge DC-DC converter prototype employing the improved planar transformer structure has been constructed, over 96% efficiency is achieved and a 2.7% improvement compared to the non-interleaving structure is obtained....