Study On The Chemical Constituents And Antiviral Activitities Of Polygala Fallax Hemsl

The chemical constituents and antiviral activities of Polygala fallax Hemsl. were studied in this thesis.The inhibitory activities of the ethanol extract of Polygala fallax Hemsl.and its solvent fractions against Coxsackie B3 virus (Cox B3),Herpes simplex virus 1(HSV-1) and Respiratory syncytial virus(RSV) were studied with Cytopathic Effect Reduction Assay(CPE)and 3-(4,5-Dimethylthiazo1-2-yl)-2,5-diphenyltetrazolium bromide(MTT) The results indicated that the petroleum ether fraction and ethyl acetate fraction possessed certain inhibitory effects against HSV-1 with the 50% inhibitory concentrat- tion(IC50) of 62.5μg,/mL and the selective index(SI) of 3 and 6 respectively.Ten compounds and two mixtures were isolated from the ethy1 acetate fraction of PolygaIa fallax Hemsl. by various separaion methods such as silica gel column chro- matography, sephadex LH-20 chromatography, polyamide column chromatography and semi-preparative HPLC. The structures of ten compounds had been identified with spectral evidences to be palmitic acid(1), 1,3-dihydroxy-2-methylxanthone(2), stigmasta-7,trans-22-dien-3-ol(5), p-hydroxybenzalde(6), 1,3-dihydroxyxanthone(7), 1,3-dihydroxy-2-methoxyxanthone(8), 1-methoxy-2,3-methylenedioxyxanthone(9), 1,7-dihydroxy-2,3-methylenedioxyxanthone(10), p-hydroxy-benzoic acid(11), meth- ylprotocatechuate(14).Mixture 3 were identified to be methyl-p-hydroxybenzoate(3), benzoic acid methylester(4). Mixture 12 were identified to be 3,5-dimethoxy-4-hydr- oxybenzaldehyde(12),3,5-dimethoxy-4-hydroxyacetophenone(13). Compound 1,2,3, 4,6,7,12,13,14 were found from this plant for the first time, compounds 2,3,4,6,12,13, 14 were found from this genus Polygala for the first time, compound 2 was found from natural products for the first time.The isolated xanthones were tested for their antiviral activities in vitro by the me- thods mentioned above.The results showed that 1,3-dihydroxy-2-methylxanthone(2), 1,3-dihydroxyxanthone(7) and 1,3-dihydroxy-2-methoxyxanthone(8) were found to be active against Cox B3 and HSV-1 virus. The IC50 values of 1,3-dihydroxy-2-meth- ylxanthone(2) were 11.7 and 10μg/mL respectively, and the SI values were＞6.4 and 3.8. The IC50 values of 1,3-dihydroxyxanthone(7) were 30.2 and 32.5μg/mL respect- ively, and the SI values were＞16 and 4.3 respectively. The IC50 values of 1,3-dihydr- oxy-2-methoxyxanthone(8) were 29.7 and 26μg/mL, and the SI values were both 2.7.