Effects of purified ginseng saponins on multilamellar liposomes

To elucidate the mode of interaction between purified ginseng saponins and liposomes, the effects of ginseng saponins at concentrations below and above their critical micelle concentration on the osmotic behavior of liposomes were observed. Liposomes composed of egg phosphatidylcholine (PC), phosphatidic acid (PA) and/or cholesterol (Ch) behave as an ideal osmometer and this activity was described by the linear relationship between (1/A450)3/2 and Cin/Cout. Total saponin prepared from the lateral roots of ginseng cultivated in Korea interacted with multilamellar liposomes and prevented them from behaving as an ideal osmometer. 20-S-Protopanaxadiol saponin showed similar activity but 20-s-protopanaxatriol saponin had weak activity. Ginsenoside Rb1 whose genin is 20-S-protopanaxadiol, disturbed osmotic behavior of Ch-free liposomes but not Ch-containing liposomes as monomers and lyzed both liposomes as micelles. Rg1 whose genin is 20-S-protopanaxatriol, showed no activity on liposomes with or without Ch. It can be suggested that ginseng saponins may interact with and destroy liposomal membranes and that structure of sugar moiety is an important factor to their activities. Ch is not a target in this interaction but suppresses the activity of ginseng saponins.