Study On The Chemical Constituents With Anti-MRSA Activity From Gnetum Pendulum

Objective To study the chemical constituents with anti-MRSA activity from Gnetum pendulum.Methods Using normal phase silica gel column chromatography, Sephadex LH-20 gel column chromatography and semi-preparative RP-HPLC, nine compounds were isolated from the ethanol extract of Gnetum pendulum and their structures were identified by ESI-MS and ’H NMR. Using methicillin-resistant Siaphylococcus aureus (MRSA) as test bacteria, the in vitro antibacterial activities of the isolated compounds were investigated.Results The nine isolated compounds were identified respectively as protoeatechuic acid methyl ester, gnetol, resveratrol, protoeatechuic acid, vanillin, ferulic acid, isorhapontin, gnetifolin E and gnetuhainin A by spectroscopic analysis, among which protoeatechuic acid methyl ester, gnetol, protoeatechuic acid, vanillin, ferulic acid, gnetifolin E and gnetuhainin A were isolated from this plant for the first time. In vitro tests of antibacterial activity showed that among them, protoeatechuic acid methyl ester, resveratrol, protoeatechuic acid and vanillin had potent antibacterial activities against MRSA, their MICs (mg-L -1) were 2560, 256,1280 and 2560 and MBCs (mg-L-1) were 2560,1280,5120 and 2560, respectively, but the others had no activity.Conclusions The nine isolated compounds were identified from Gnetum pendulum, among which protoeatechuic acid methyl ester, gnetol, protoeatechuic acid, vanillin, ferulic acid, gnetifolin E and gnetuhainin A were isolated from this plant for the first time. The antibacterial activity of compounds were assayed in vitro against the MRSA. Among them, protoeatechuic acid methyl ester, resveratrol, protoeatechuic acid and vanillin had potent antibacterial activities and the remaining compounds had no activity. Compared with the anti-MRSA activity of the compounds isolated from Gnetum pendulum, we found that resveratrol and 3,5-dihydroxy-4-methoxystilbene and pinosylvin with stilbene have similar activity, but gnetol and isorhapontin and gnetifolin E no this activity. Among them, pinosylvin with good activity and gnetol with no activity, whose difference is only less 2 hydroxyl in 10 and 14 position. In addition, the activity of silverpine is better than resveratrol, indicated that stilbene with 12-hydroxyl decreased their anti-MRSA activity.