Mechanism of antiviral activity of triterpenoid saponins

Triterpenoid saponins are naturally occurring sugar conjugates of triterpenes possessing various biological activities, including antiviral action. Two substances isolated from natural sources were tested against herpes simplex virus type 1 replication, They did not show evidence of cytotoxicity under antiviral test conditions. The triterpenoid saponin, isolated from a Brazilian plant (s21), represents the oleanane group and inhibited herpes simplex virus type 1 DNA synthesis. The triterpenoid saponin, isolated from a Chinese plant (s17), represents the ursane group and seemed to inhibit viral capsid protein synthesis of herpes simplex virus type 1. Copyright (C) 1999 John Wiley & Sons, Ltd.