Studies On The Chemical Constituents And Anti-HBV Activity Of Jasminum Officinale L.var.grandiflorum

Hepatitis B virus (HBV) infection causes acute and chronic hepatitis B. It is responsible for developing cirrhosis and primary hepatocellular carcinoma. Screening safe and effective anti-HBV compounds in traditional Chinese medicine provides a large opportunity for the development of anti-HBV drugs.During literature investigation , We selected seventeen traditional Chinese medicines for anti-HBV screening in vitro , employing the method of HepG2 2.2.15 cell model and using inhibition activity of HBeAg and HBsAg as the activity-evaluating marker. Five traditional Chinese medicines were found to have anti-HBV activity during our experiments. Among them, the anti-HBV activities of Jasminum officinale L. var. grandiflorum, Pogonatherum crinitum (Thunb.) Kunth and Ranunculus chinensis Bge. are significant. The extract of J. officinale showed the most prominent anti-HBV activity, so our studies on chemical constituents and anti-HBV activity of J. officinale has been processed deeply.Thirty-three compounds were isolated from the flower buds of J. officinale, among them the structures of thirty-one compounds were determined on the basis of chemical and spectroscopic analysis, including eleven iridoid glycosides, six triterpenoid saponins and eight flavones. Three glycosides are new compounds, namely jasgranoside (compound 8), kaempferol-3-O-α-L-rhamnopyranosyl-(1→3) -[α-L-rhamnopyranosyl(1→6)]-β-D-galactopyranoside (compound 17) and 3-O-α- -L-rhamnopyranosyl(1→2)-β-D-xylopyranosyl-hederagenin-28-O-β-D-galactopyranosyl(1→6)-β-D-galactopyranosyl ester (compound 20). 3',4',5,5',7-pentamethoxyl flavone (compound 12), 2α,3β,23-trihydroxyolean-12-en-28-oic-O–β-D-glucopy ranosyl ester (compound 21), 2α,3β,23-trihydroxyolean-12-en-28-oic-O-α-L- rhamnopyranosyl–(1→4)-O-β-D- glucopyranosyl-(1→6)-O-β-D-glucopyranosyl ester (compound 22), hederagenin-3-O-β-D-glucopyranosyl(1→3)-α-L-arabinopyranoside (compound 23), hederagenin-3-O-β-D-xylopyranosyl(1→3)-α-L-rhamnopyranosyl (1→2)-α-L– arabinopyranoside (compound 24) and hederagenin-3-O-α-L-rhamnopy ranosyl(1→2)-α-L-arabinopyranoside (compound 25) were isolated from the genus Jasminum for the first time.Anti-HBV activities of seven ingredients have been discovered by the preliminary anti-HBV activity assay. 8-epi-kingiside and jaspolyoside dose dependently inhibited the secretion of HBsAg, with IC50 data 82.6, 70.5μg/ml respectively. Oleuropein and 3,4-dihydroxyphenylethanol showed strong dose-dependent inhibition of the secretion of HBsAg, with IC50 data 23.2, 26.6μg/ml respectively. Compound 23, 24 and 25 dose-dependently inhibited the secretion of HBsAg, with IC50 data 42.7, 31.1, 51.6μg/ml respectively.Because of the small amounts of the other active compounds, only oleuropein's anti-HBV activity in vivo has been evaluated. The anti-HBV effects of oleuropein was also demonstrated in the model of Beijing ducks infected by duck hepatitis B virus (DHBV) in vivo. Ducks were administered with oleuropein 80mg/kg/d. The treatment was started at 7 days after infection. The amount of DHBV DNA in serum was determined by both densitometry and image analysis of radioautographic plate. The results indicated that oleuropein (80mg/kg/d) inhibited the levels of DHBV DNA from 5 days after treatment. Preliminary results showed that the maximal tolerance dose was higher than 2g/kg/d. Oleuropein's anti-HBV activity was discovered for the first time.The anti-HBV activities of 8-epi-kingiside, jaspolyoside , compound 23, compound 24 and compound 25 were discovered for the first time. Their anti-HBV activities in vivo might be better than oleuropein if they were demonstrated in the model of Beijing ducks infected by duck hepatitis B virus (DHBV).Analysis of initial structure-function relationships showed that polyphenol unit might be the major group of iridoid glycosides which have anti-HBV activities .Carboxyl group of C-28 might be the main unit of anti-HBV active hederagenin and the type, link style of saccharide also influence the anti-HBV activity of hederagenin.The results of our research suggested that iridoid glycosides and triterpenoid saponins might be the primary anti-HBV active ingredient of the ethanol extract of J. officinale. Oleuropein , which has notable anti-HBV activity in vitro and in vivo, might become a new leading natural compound for the synthesis and development of new anti-HBV drugs.