Figure 4 (IMAGE) Institute for Basic Science Caption Astersaponin I, lancemaside A, and platycodin D are triterpenoid saponins with central ringed hydrocarbon structures similar to that of cholesterol. This allows one side of the saponin to become readily embedded within the cell membrane. It is believed that the polysaccharide chain protruding from the cell membrane is what prevents membrane fusion from occurring. Credit Institute for Basic Science Usage Restrictions Attribution Required License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.