Mohandoss, Sonaimuthu; Stalin, Thambusamy
The formation of an inclusion complex between 1,2-dihydroxyanthraquinones (1,2-DHAQ) and β-cyclodextrin (β-CD) has been studied by UV-visible, fluorescence spectroscopy and electrochemical methods. The stoichiometric ratio of the inclusion complex was found to be 1 : 1 and the binding constant was evaluated using the Benesi-Hildebrand equation. The peak currents (Ipa and Ipc) change drastically with increasing β-CD concentration and the peak potentials (Epa and Epc) shifted. A mechanism is proposed to explain the inclusion process. A stable solid inclusion complex was prepared using a co-precipitation method and it is characterized by FT-IR, XRD, DSC, SEM, and (1)H NMR that confirmed the formation of the inclusion complex. The β-CD and 1,2-DHAQ inclusion complex obtained by molecular docking studies is in good correlation with the results obtained through experimental methods using PatchDock and FireDock servers. The virtual study of the energetically favorable complex was carried out by PM3 calculations and molecular orbital energy studies suggest that orientation A is more favourable than orientation B.
Full Text Available This paper reports on the development of adsorptive cathodic stripping voltammetric (AdCSV method with 1,2-dihydroxyanthraquinone or Alizarin (AZ as a complexing agent used in the simultaneous determination of ultra trace of Cd and Zn because it has a good sensitivity, and selectivity. The influence of several parameters was studied: the effects of 1,2-dihydroxyanthraquinone or Alizarin (AZ concentration, pH, accumulation potential, and accumulation time. The relative standard deviation (RSD, and recovery is determined to get the accuracy and precision method. It also determined the limit of detection (LOD of the method to get the sensitivity. In this case, the optimum conditions were AZ concentration of 0.5 mM, pH 5, step deposition (70 s, -0.5 V. This method has been applied in water samples successfully, was obtained (Cd 23, and Zn 124 µg/L, LOD (Cd 0.006, and Zn 0.004 µg/L, RSD (Cd 0.4, and Zn 1.4 % (n = 10, recovery (Cd 99.36, and Zn 99.28%. The Atomic absorption spectrometric (AAS method is used as a comparison AdCSV optimum, was obtained (Cd 16, and Zn 115 µg/L.
Cysewski, Piotr; Jeliński, Tomasz
The electronic spectrum of four different anthraquinones (1,2-dihydroxyanthraquinone, 1-aminoanthraquinone, 2-aminoanthraquinone and 1-amino-2-methylanthraquinone) in methanol solution was measured and used as reference data for theoretical color prediction. The visible part of the spectrum was modeled according to TD-DFT framework with a broad range of DFT functionals. The convoluted theoretical spectra were validated against experimental data by a direct color comparison in terms of CIE XYZ and CIE Lab tristimulus model color. It was found, that the 6-31G** basis set provides the most accurate color prediction and there is no need to extend the basis set since it does not improve the prediction of color. Although different functionals were found to give the most accurate color prediction for different anthraquinones, it is possible to apply the same DFT approach for the whole set of analyzed dyes. Especially three functionals seem to be valuable, namely mPW1LYP, B1LYP and PBE0 due to very similar spectra predictions. The major source of discrepancies between theoretical and experimental spectra comes from L values, representing the lightness, and the a parameter, depicting the position on green→magenta axis. Fortunately, the agreement between computed and observed blue→yellow axis (parameter b) is very precise in the case of studied anthraquinone dyes in methanol solution. Despite discussed shortcomings, color prediction from first principle quantum chemistry computations can lead to quite satisfactory results, expressed in terms of color space parameters.
Synergistic effects of a photooxidized polycyclic aromatic hydrocarbon and copper on photosynthesis and plant growth: evidence that in vivo formation of reactive oxygen species is a mechanism of copper toxicity.
Babu, T S; Marder, J B; Tripuranthakam, S; Dixon, D G; Greenberg, B M
Heavy metals and polycyclic aromatic hydrocarbons (PAHs) are often cocontaminants in industrialized environments, yet little is known about either the extent or mechanisms of their cotoxicity. To address this shortfall, the combined effects of an oxygenated PAH, 1,2-dihydroxyanthraquinone (1,2-dhATQ), and a heavy metal, Cu2+, on photosynthesis and growth of the duckweed (Lemna gibba) were evaluated. Using assays of chlorophyll a fluorescence and photosystem I activity, 1,2-dhATQ inhibited electron transport at the cytochrome b6/f complex. Conversely, Cu2+ alone (at low concentrations) had little effect on photosynthesis. When Cu2+ was combined with 1,2-dhATQ, an increase in transient and steady-state chlorophyll a fluorescence quenching occurred relative to 1,2-dhATQ alone. Treatment of isolated thylakoid membranes with 1,2-dhATQ inhibited whole-chain linear electron transport, measured as O2 consumption using methyl viologen as the electron acceptor. However, Cu2+ plus 1,2-dhATQ resulted in active O2 consumption with or without methyl viologen as an electron acceptor. From these data, we conclude that 1,2-dhATQ renders the plastoquinone pool to a highly reduced state by inhibiting at cytochrome b6/f. Then, Cu2+ is able to mediate the transfer of electrons from reduced plastoquinone to O2, forming reactive oxygen species. At the whole-organism level, when Cu2+ and 1,2-dhATQ were mixed at concentrations that resulted in the above-mentioned impacts on photosynthesis, synergistic inhibition of plant growth was observed. This suggests a catalytic mechanism of toxicity for redox active metals, a process that could be instrumental in explaining their impacts at low concentrations.
Badria, Farid A; Ibrahim, Ahmed S
Plants that contain anthracene-derived compounds such as anthraquinones have been reported to act as anticancer besides their use for millennia to treat constipation, but the mechanism of action is still unfolding. Therefore we pursue this study to explore a new horizon in the anticancer property of these agents with relevance to mitotic arrest. To achieve this goal, the antimitotic activity of a series of naturally occurring anthracene-derived anthraquinones including anthrone, alizarin (1,2-dihydroxyanthraquinone), quinizarin (1,4-dihydroxyanthraquinone), rhein (4,5-dihydroxyanthraquinone-2-carboxylic acid), emodin (1,6,8-trihydroxy-3-methylanthraquinone), and aloe emodin (1,8-dihydroxy-3-hydroxymethylanthraquinone) were evaluated using Allium cepa root tips. Initial results revealed that the mitosis was inhibited after 3, 6, and 24 h, respectively, of incubation with 500, 250, and 125 ppm of each compound in a dose-dependent manner. Furthermore, alizarin at 500 ppm was proved to be the most active compound to arrest the mitosis after 24 h followed by emodin, aloe emodin, rhein, and finally quinizarin. Interestingly, this inhibition of mitosis was irreversible in root tips incubated with each compound at concentration of 500 ppm but not with 250 ppm or 125 ppm, where the roots regained their normal mitotic activity after 96 h post-incubation in water. This re-evaluation of an old remedy suggests that several bioactive anthraquinones possess promising anti-mitotic activity that may have the potential to be lead compounds for the development of a new class of multifaceted natural anticancer/antimitotic agents.
康文艺; 张丽; 宋艳丽
目的:寻找茜草中抑制α-葡萄糖苷酶活性的成分.方法:利用体外抑制α-葡萄糖苷酶活性模型进行追踪,采用各种色谱法分离,运用多种谱学技术鉴定结构,并对活性化合物进行酶抑制动力学研究.结果:茜草三氯甲烷提取物具有很高的活性,从中分离出3个具抑制α-葡萄糖苷酶活性的蒽醌类化合物,分别鉴定为:1,3-二羟基-2-甲基蒽醌(1),1-羟基-2一甲基葸醌(2)和1,2-二羟基蒽醌(3),其中化合物3(IC_(50)=7.97 mg·L~(-1))活性最好,与1(IC_(50)=35.96 mg·L~(-1))和2(IC_(50)=15.98 mg·L~(-1))的活性都明显高于阳性对照阿卡波糖(IC_(50)=1 081.27 mg·L~(-1)).化合物1和2为竞争性抑制类型.结论:化合物1-3为首次报道对α-葡萄糖苷酶抑制活性.%Objective: To search α-glucosidase inhibitors from Rubia cordifolia. Methed: The α-glucosidase inhibitors were isolated by the column chromatographic techniques and the bioassay-guided method in vitro. A combination of MS and NMR spectrosco-py was used to identify the chemical structures. The inhibitory kinetics of the inhibitors were also investigated. Result: The chloroform extract showed high inhibitory activity,and three active compounds were isolated and identified as 1,3-dihydroxy-2-methylanthraquinone (1), 1-hydroxy-2-methylanthraquinone (2) and 1,2-dihydroxyanthraquinone (3). The IC_(50) values of compound 1-3 were all lower than that of acarbose. Compound 1 and 2 shown competitive type manner on α-glucosidase, whereas compound 3 shown noncompetitive type model. Conclusion: Compounds 1-3 as strong inhibitors of α-glucosidase were reported for the first time.