Study On The Chemical Constituents Of Sabia Discolor Dunn

Sabia discolor Dunn has abundant resources,strong growth ability and valuable medicinal prospects,which is mainly distributed in Zhejiang,Fujian,Guangxi and other provinces.In order to further understand the chemical constituents of S.discolor Dunn and discover its pharmacological activity,the chemical constituents and antioxidant activity of S.discolor Dunn were studied in this research.Air-dried S.discolor Dunn(3.8 kg)was extracted by ethanol at room temperature.The crude extract was suspended in H2O and then partitioned sequentially by petroleum ether and ethyl acetate.3.8 g of petroleum ether extract and 30.0 g of ethyl acetate extract were got.Both extracts were purified by column chromatography on silica gel and Sephadex LH-20.The compounds were identified by modern spectroscopic methods.Furthermore,the antioxidant activities of both extracts were evaluated by DPPH and ABTS bioassays.Twenty-one compounds were isolated from S.discolor Dunn and fifteen of them were identified as 20-taraxastene-3a,28-diol(1),20-hydroxy-lupan-3-one(2),(20S)-3-oxo-20-hydroxytaraxastane(3),oleanolic acid(4),monogynol A(5),ent-18Hα,3β,20β-ursanediol(6),3β,20β-dihydroxytaraxastane(7),juglangenin A(9),1-oxo-erythrodiol(10)and 1-oxo3,16-oleandiol(11),1α,3β-olean-12-ene-1,3-diol(12),1α,3β-dihydroxyl-olean-12-en-28-oic acid(14),dibutyl phthalate(16),diisobutyl phthalate(17),β-stigmasterol(18),respectively.Among them,compounds 6 and 11 are new ones,compounds 1,5,9,10 and 12 were obtained from the genus Sabia for the first time and compounds 2,3,7,14 and 16-18 were obtained from S.discolor Dunn for the first time.DPPH and ABTS bioassays were used to evaluate the antioxidant activity of both extracts.The results showed that both extracts exhibited antioxidant activity.And,the DPPH and ABTS+ scavenging abilities of both extracts were gradually increased in a dose-dependent manner.In DPPH bioassay,the DPPH scavenging ability of ethyl acetate extract(IC50=1.34 mg/mL)was similar as that of ascorbic acid.