Interaction of saponins with red blood cells as well as with the phosphatidylcholine liposomal membranes.

Abstract

Various purified saponins were examined for their lytic activities against mammalian erythrocytes and their activities to interact with liposomal membranes, and were classified into at least five categories according to their reactivities. 1. Digitonin, F-gitonin, dioscin and paris saponin Pa : These saponins showed hemolytic activity and induced permeability change in liposomal membranes containing cholesterol. The interaction of these saponins with cholesterol was "irreversible". The interaction was independent of acyl chain lengths of phosphatidylcholine. 2. Gracillin : This saponin showed hemolytic activity but did not induce permeability change of liposomal membrane with cholesterol, except those containing distearoyllecithin. The interaction of gracillin with cholesterol was "irreversible". 3. Akebia saponin B, C, PD and PG : These showed hemolytic activities and induced the permeability changes of liposomes with cholesterol. Their activities to induce permeability changes were affected by chain length of phosphatidylcholine. With increase of chain length, the sensitivity of liposomes toward these saponins decreased. The interaction of saponins with cholesterol was "reversible". 4. Chikusetsusaponin III : This saponin has a weak lytic activity against erythrocytes and has the activity to induce permeability change of liposomes without cholesterol. Cholesterol in the phosphatidylcholine liposomes depressed the sensitivity of the liposomal membrane to the saponin. 5. Chikusetsusaponin V and akebia saponin E and Pk : These compounds ("bisdesmosidisch") showed neither detectable activity to lyse erythrocytes nor to damage liposomal membranes. liposomal membranes.