OBJECTIVETo study the chemical constituents and activity of total flavonoids contained in Yushen Tang,in order to lay a foundation for defining active consituents of the prescription and their mechanism.

METHODThe activity of total flavonoids contained in Yushen Tang were evaluated by in vitro H2O2-induced human umbilical vein endothelial cell injury experiment. The chemical constituents were separated and purified by such methods as silica column chromatography, macroporous resin chromatography, sephadex and HPLC preparation,and their structures were identified on the basis of their spectral data and physicochemical properties.

RESULTTotal flavonoids contained in Yushen Tang showed the effects in inhibiting hydrogen peroxide-induced human umbilical vein endothelial cell (HUVEC) injury and down-regulating PAI-1 expression (P<0.05). Nine flavonoids were separated from total flavonoids contained in Yushen Tang and identified as calycosin (1), linarin (2), 3',4',7 -trihydroxyflavone-7-O-beta-D-glucopyranoside (3), 7,3'-dihydroxy-4'-methoxyflavone-7-glucoside (4), quercetin (5), kaempferol (6), rutin (7), pratensein-7-O-beta-D-glucoside (8) and 7-O-glucosyl liquiritigenin (9).

CONCLUSIONTotal flavonoids contained in Yushen Tang showed the effect in inhibiting HUVEC injury. All of the nine flavonoids were separated from Yushen Tang for the first time, and compounds 1,3,4,8,9 may be derived from astragalus mongholicus, while compounds 4,5-7 may be derived from herba cepbalanoplosis segeti and hairyvein agrimony. Among them, compounds 3,4 and 9 were seperated from single ingredient of the prescription for the first time.