Antiviral activity against herpes simplex virus type 2 of extracts from Cerbera odollam Gaertn., Clausena excavata Burm.F., Coleus amboinicus Lour., Phyla nodiflora (L.) Greene. and Thevetia peruviana Schum

Abstract

Thirty-five extracts from the leaves of Cerbera odollam Gaertn., Clausena excavata Burm. F., Coleus amboinicus Lour., Thevetia peruviana Schum. and leaves and apex of Phyla nodiflora (L.) Greene. Were tested for antiviral activity in vitro against HSV-2 strain 186 and 38 HSV-2 isolates by plaque reduction assay using Vero cell line. The inactivation activity of active extracts from 5 plants were showed in methanol fraction (F1), chloroform fraction (F2), hexane fraction (F4) and aqueous- hexane fraction (F5). The most active extracts of C. odollam Gaertn., C. excavata Burm.F., C. amboinicus Lour., P. nodiflora (L.) Greene. and T. peruviana Schum against HSV-2 strain 186 were F5, F2, F2, F4 and F2, respectively. The 50% Effective Dose (ED50) of these extracts were 4.25, 9.25, 3.25, 16.25 and 3.25 ug/ml, respectively. While the lowest ED50 (ug/ml) of C. odollam Gaertn., C. excavata Burm. F., C. amboinicus Lour., P. nodiflora (L.) Greene. and T. peruviana Schum. against HSV-2 isolates were 4.99+0.91 (F5), 8.97+0.76 (F2), 3.57+0.77(F2), 20.90+3.14(F4) and 3.04+0.70 (F2), respectively. The results showed 20 extracts from 5 plants inhibited plaque formation of HSV-2 by inactivation activity. ED50 of acyclovir (ACV) against HSV-2 strain 186 and HSV-2 isolates were 0.5 and 0.59 ug/ml. This study has indicated some of the ethnobotanical reports of Thai medicinal plants having antiviral properties against HSV-2 clinical isolates using biological assay in vitro.