In vitro anti-enterovirus 71 activity of gallic acid from Woodfordia fruticosa flowers

Aims: The anti-enterovirus 71 (EV71) activity of six Nepalese plants' extracts and gallic acid (GA) isolated from Woodfordia fruticosa Kurz (family; Lythaceae) flowers were evaluated in Vero cells. Methods and Results: The anti-EV71 activity of tested compounds was evaluated by a cytopathic effect reduction method. Our results demonstrated that flowers' extracts of W. fruticosa exerted strong anti-EV71 activity, with a 50% inhibitory concentration (IC50) of 1 center dot 2 mu g ml-1 and no cytotoxicity at a concentration of 100 mu g ml-1, and the derived therapeutic index (TI) was more than 83 center dot 33. Rivabirin showed no antiviral activity against EV71. Furthermore, GA isolated from W. fruticosa flowers exhibited a higher anti-EV71 activity than the extract of W. fruticosa flowers, with an IC50 of 0 center dot 76 mu g ml-1 and no cytotoxicity at a concentration of 100 mu g ml-1, and the derived TI was 99 center dot 57. Conclusions: This study demonstrated that flower extracts of W. fruticosa possessed anti-EV71 activity and GA isolated from these flowers showed stronger anti-EV71 activity than that the extracts. Significance and Impact of the Study: Our results suggest that the GA from W. fruticosa flowers may be used as a potential antiviral agent.