Secoiridoid analogues from the fruits of Ligustrum lucidum and their inhibitory activities against influenza A virus.
A phytochemical study focusing on the secoiridoid components in the fruits of Ligustrum lucidum was carried out, which finally led to the isolation of nine secoiridoid glycosides (1-9) together with two secoiridoids (10, 11). The structures of all compounds were established mainly by NMR and MS experiments as well as the necessary chemical evidence, of which 1, 2, 4 (ligulucisides A-C), 10 and 11 (liguluciridoids A and B) were identified as new secoiridoid analogues. An in vitro antiviral bioassay indicated that 1, 4, 6, and 10 displayed the inhibitory activities against influenza A virus with the IC50 values of 16.5, 12.5, 13.1, and 18.5 μM, respectively, which were better than the positive control Ribavirin (IC50 22.6 μM). .
Secoiridoids from Olea europaea
Abstract Three new secoiridoids have been isolated from the leaves of Olea europaea along with the previously reported. The compounds were identified by spectral means.
[Active components of Ligustrum lucidum inhibiting hepatitis C virus replicase activity].
Based on previous report that the Chinese herb Ligustrum lucidum (LL) extract directly inhibited hepatitis C virus (HCV) replicase (NS5B) activity, the active components of LL extract to inhibit HCV NS5B activity and their inhibition mode were investigated in this study. LL extract was separated using ethyl acetate and thin layer chromatography (TLC). The inhibitory activity of separated fractions on HCV NS5B was analyzed by the inhibitory assay of NS5B activity. The results showed that only fractions 1 and 2 inhibited NS5B activity, and fraction 2 possessed higher inhibitory activity than fraction 1. HPLC analysis combined with inhibitory assays indicated that ursolic acid and oleanolic acid are the active components within fractions 1 and 2 to inhibit NS5B activity, separately. Moreover, oleanolic acid possessed higher inhibitory activity than ursolic acid. Further inhibition mode analysis found that both oleanolic acid and ursolic acid suppressed NS5B activity as noncompetitive inhibitors. The Ki values of ursolic acid and oleanolic acid were about 4.7 microg x mL(-1) (10 micromol x kg(-1)) and 2.5 microg x mL(-1) (5.5 micromol x kg(-1)), respectively. Taken together, these results demonstrated that oleanolic acid and ursolic acid suppressed NS5B activity as noncompetitive inhibitors, implying that the two natural products have potential value for HCV therapy.