Studies On Chemical Constituents Of The Leaves Of Bergenia Purpurascens

Bergenia purpurascens,belonging to the genus Bergenia(Saxifragaceae),is widely distributed inTibet,Yunnan and Sichuan.B.purpurascens has long been used as a Chinese medicine for the treatment of cough,chronic bronchitis,weak dizziness,dysentery and so on.In order to study the chemical constituents and medical valueof B.purpurascens,develop the medicinal resources of plants,so this research aims to investigate the constitutions of the leaves of B.purpurascens comprehensively,to find more biological active components for further medicinal application.The research mainly used repeated chromatography on silica gel colum and other separation material like MCI?Sephadex LH-20 to obtain 25 compounds from the ethanol extracts of B.purpurascens.The structures of 25 compounds(including one new compound)were identified on the basis of their spectrum physical and chemical properties:taraxerol(Y1),?-sitosterol(Y2),betulinic acid(Y3),ocimol(Y4),bergen-in(Y5),daucosterol(Y6),arbutin(Y7),kaempferol(Y8),3?,5?-dihydroxy-15-cinna-moyloxy-14-oxolathyra-6Z,12E-diene(Y9),ursolic acid(Y10),hydroquinone(Y11),oleanolic acid(Y12),ferulic acid(Y13),2?-hydroxyursolic acid(Y14),p-hydroxybenzoic acid(Y15),protocatechuic acid(Y15),gallic acid(Y16),11-O-gal-loylbergenin(Y18),11-O-(4'-hydroxybenzoyl)bergenin(Y19),quercetin(Y20),ardimerin(Y21),1-O-?-D-glucopyranosyl-2-methoxy-3-hydroxyl-phenylethene(Y22*),glucose(Y23),sucrose(Y24),rutin(Y25).These compounds contain different types of compounds,such asterpenoid(two terpene,three terpene),phenols,flavonoids,organic acids,steroids and so on.Among them,Y22*was a new compound,Yl,Y4,Y9,Y10,Y12,Y14,Y21 were firstly found from the ethanol extracts of this plant and even firstly found from the genus Bergenia.In vitro anti-proliferative activities of some compounds and new compound Y22*on four human cancer cell lines(MGC-803,T24,NCI-H460,HepG2)were evaluated,the HCPT was used as a control.The results showed that compared with other known compounds,the new compound Y22*had the best inhibitory activity,the IC50 values of 18.10±1.15?M against MGC-803 cells,the IC50 values of 20.93±1.07?Magainst Hep-G2 cells,the IC50 values of 17.69±1.17 ?M against NCI-H460 cells,the strongest inhibitory effect on T24 cells was 14.96±1.04.Compound Y22*was selected to investigate it mechanism of antitumor against T24 cell line.Fluorescence staining assays(AO/EB and Hoechst 33258 staining)and flow cytometric analysis showed that Y22*induced apoptosis.Further analysis indicated after dosing increased intracellular level of ROS.The levels of Caspase-3,Bax,Bcl-2 of compound Y22*were measured by Western blot.Our results suggest that Y22*increased the expression levels of Caspase-3,Bax,decreased the expression levels of Bcl-2.The present investigation illustrated compound Y22*might be used as a potential antitumor chemotherapy candidate.