Antiherpes simplex virus activities of extracts from Glycosmis Pentaphylla (RETZ.)DC., Ipomoea Maxima (LINN.F.) Don, and Willughbeia Edulis ROXB

Abstract

The extracts from the leaves of 3 medicinal plants : Glycosmis pentaphylla (Retzj) DC, Ipomoea maxima Linn, f., and Willughbeia edulis Roxb. Were tested for antiviral activity in vitro against HSV-1 strain KOS and HSV-2 strain Baylor 186 by inactivation, prophylactic activity and plaque reduction assay in Vero cell line. The inactivation assay revealed the highest antiviral activities of these three plant extracts. The inactivation activity of active extracts from three plants were showed in ethanol fraction (F1), chloroform fraction (F2), methanol fraction (F3), hexane fraction (F4), and aqueous fraction (F5). The most active extracts of G. pentaphylla, I. maxima and W. edulis were F4, F3 and F4, respectively. The 50% effective dose (EC₅₀) of these extracts against HSV-1 (HSV-2) were 11.36±0.51(9.66±0.20), 9.14±0.49 (10.11±0.21), 15.05±0.46(18.87±0.86) µg/ml, respectively. The selective index for anti-HSV-1 (anti-HSV-2) of 80.93( 95.17), 15.46 (13.97) and 71.36 (56.91) were observed for F4/G. pentaphylla , F3/I. maxima and F4/W. edulis, respectively. The most active fraction of each plant, F4/G. pentaphylla, F3 /I. maxima and F4/W. edulis were selected for preliminary mechanism study of antiviral activity in post binding assay, penetration inhibition assay and virus yield inhibition assay, In post binding assay, the maximum of inhibition in plaque forming at concentration of 1600 ug/ml were observed at 55% for F4/G. pentaphylla, 70% for F3 /I, maxima, and 55% for F4 /W. edulis. For the penetration assay, the maximum inhibition in plaque forming were exhibited at 15 min of penetration of HSV-1 and HSV-2 into the cells were 60% for all 3 extracts, F4/G. pentaphylla, F3 /I, maxima, and F4/W. edulis. In virus yield inhibition assay, it was found that the percent inhibition of plaque forming was maximum at 72 h incubation and was concentration dependent for all 3 plant extracts. This study has indicated some of the ethanobotanical reports of these three medicinal plants having in vitro antiviral properties against herpes simplex virus. These 3 medicinal plants will be further studied and used for anti-herpes simplex virus drug development.