Anti-herpes virus activity of fabaceous triterpenoidal saponins')

Anti-herpes simplex virus type 1 (HSV-1) activity of oleanane-type triterpenoidal saponins obtained from some fabaceous plants were examined. Among sophoradiol glycosides, the order of potency was kaikasaponins III>I>>sophoradiol monoglucuronide. It was suggested that the trisaccharide group showed greater action than the disaccharide group. Neither the monoglucuronide of sophoradiol nor that of soyasapogenol B showed activity. Among the trisaccharide group of soyasapogenol B, the order of activity was azukisaponin V>soyasaponin II>astragaloside VIII>>soyasaponin I. Therefore, the saponin having a glucosyl unit in the central sugar moiety seemed to show greater action. In comparison with the activities for a group having the same trisaccharide, the potency of the sapogenol moieties was found to be in the order of soyasapogenol E>sophoradiol>>soyasapogenol B. Hence, the carbonyl group at C-22 would be more effective than the hydroxyl group in anti-HSV-1 activity, while the hydroxyl group at C-24 could reduce the activity.