Transformation of trollioside and isoquercetin by human intestinal flora in vitro / 中国天然药物

The present study was designed to determine the intestinal bacterial metabolites of trollioside and isoquercetin and their antibacterial activities. A systematic in vitro biotransformation investigation on trollioside and isoquercetin, including metabolite identification, metabolic pathway deduction, and time course, was accomplished using a human intestinal bacterial model. The metabolites were analyzed and identified by HPLC and HPLC-MS. The antibacterial activities of trollioside, isoquercetin, and their metabolites were evaluated using the broth microdilution method with berberine as a positive control, and their potency was measured as minimal inhibitory concentration (MIC). Our results indicated that trollioside and isoquercetin were metabolized by human intestinal flora through O-deglycosylation, yielding aglycones proglobeflowery acid and quercetin, respectively The antibacterial activities of both metabolites were more potent than that of their parent compounds. In conclusion, trollioside and isoquercetin are totally and rapidly transformed by human intestinal bacteria in vitro and the transformation favors the improvement of the antibacterial activities of the parent compounds.

Triterpenes constituents from male flowers of Eucommia ulmoides / 中国中药杂志

Nine triterpenes compounds were isolated from the male flowers of Eucommia ulmoides by recrystallization and chromatographic techniques over silica gel, Sephadex LH-20, and RP-18 gel. Their chemical structures were identified on the basis of spectral analysis and as 3-oxo-12-en-ursane-28-O-α-L-arabinofuranosyl (1 --> 6) -β-D-glucopyranoside (1), 2α, 3β-dihydroxyurs-12-en-28-oic acid(28 --> 1) -β-D-glucopyranosyl ester (2), ursolic acid (3), α-amyrin (4), uvaol (5), ursolic acid acetate (6), 3-O-acetate oleanoic acid (7), betulinic acid (8), and betulinol (9). Compound 1 was a new compound, and compounds 2, 4-7 were isolated from the Eucommiu genus for the first time. Cytotoxic activity was tested for all the compounds against K562 and HepG2 cells. The results showed that only compound 3, exhibited cytotoxic activity.