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ABSTRACT: Riccardin F and pakyonol, macrocyclic bisbibenzyls from Plagiochasm intermedium, have been confirmed to possess antifungic activities against Candida albicans. Herein, we evaluated their anti-tumor activity in vitro by employing K562 and K562/A02 cells, the well-known adriamycin (ADR)-induced multidrug resistance (MDR) tumor cell lines over-expressing P-glycoprotein (P-gp). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assays showed that riccardin F and pakyonol ranging from 0 to 6 μg/mL exhibited no inhibitory effects on the growth of the two cell lines. However, in the presence of 3 μg/mL riccardin F or pakyonol (non-cytotoxic concentration), the IC50 of ADR against K562/A02 cells decreased by 2.51- and 4.78-fold, respectively. Flow cytometry showed that riccardin F and pakyonol significantly enhanced the accumulation of ADR in K562/A02 cells. Furthermore, fluorescence intensity detection revealed that the two natural products remarkably increased the retention of rhodamine-123 in K562/A02 cells rather than in K562 cells, indicating that the major cause for riccardin F and pakyonol to reverse P-gp-mediated MDR in K562/A02 cells is probably due to the constrained transport activity of P-gp. This study explores the potential application of bisbibenzyl type compounds as modulators of P-gp-mediated MDR in tumor cells.
Bioscience trends 10/2011; 5(5):192-7. · 0.97 Impact Factor
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ABSTRACT: A separation method for the hepatoprotective drug silybin and its metabolites by RP-HPLC was described. Based on this separation, the stereoselectivity of the metabolism of silybin was investigated by incubation of the drug and its two diastereoisomers with bovine liver microsomes. Information about the structures of these metabolites was obtained, using UV, HPLC/MS and NMR spectra. Four major metabolites (M(1), M(4) of silybin A and M(2), M(5) of silybin B), were prepared by preparative HPLC, and their configurations were accomplished by NMR spectra. A HPLC method was used to quantify the metabolites. The results showed that silybin was extensively metabolized and the major sites for glucuronidation were the C-20, C-7, at phenolic OH groups. Furthermore, the results obtained reveal that there was significant stereoselectivity in the glucuronidation process of silybin. Silybin B was glucuronidated at a more efficient rate than its diastereoisomer, and glucuronidation of silybin B was much preferred at the 20 position, while that of silybin A was similar at both 7 and 20 position.
Journal of Pharmaceutical and Biomedical Analysis 04/2004; 34(5):1071-8. · 2.97 Impact Factor
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ABSTRACT: By the method of UV second order derivative spectra, baicalin in contents in the Lanqin Oral Liquid were determined. Able to eliminate the influence of other constituents, this method is simple, rapid, sensitive and accurate.
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica 03/1996; 21(2):97-9, 128.
