Kalopanaxsaponin A is a basic saponin structure for the anti-tumor activity of hederagenin monodesmosides

Hederagenin, delta -hederin {hederagenin alpha-(L)-arabinoside}, kalopanax-saponin A {hederagenin 3-O-alpha-(L)-rhamnosyl (1 -->2)-alpha-(L)-arabinoside}, kalopanaxsaponin l [hederagenin 3-O-beta-(D)-xylosyl (1 -->3)-alpha-(L)-rhamnosyl(1 -->2)-alpha-(L)-arabinoside], and sapindoside C [hederagenin 3-O-beta-(D)-glucoyl(1 -->4)-beta-(D)-xylosyl (1 -->3)-alpha (L)-rhamnosyl(1 -->2)-alpha-(L)-arabinoside] were isolated from stem bark of Kolopanax pictus Nakai (Araliaceae). Among glycosides of hederagenin, disaccharide (kalopanaxsaponin A, commonly also called alpha -hederin), trisaccharide (kalopanaxsaponin 1), and tetrasaccharide (sapindoside C) showed significant cytotoxicity on several types of tumor cells, while hederagenin itself exhibited only weak cytotoxicity and its monosaccharide (delta -hederin) was non-cytotoxic. From these results, it suggests that the arabinosyl moiety at C-3 blocks the activity of hederagenin and the position of the second sugar for glycoside linkage is also important for cytotoxicity. In the in vivo experiments, kalopanaxsaponin A (15 mg/kg, i.p.) apparently increased the life span of mice bearing Colon 26 and 3LL Lewis lung carcinoma, as well as cisplatin (3 mg/kg, i.p.). These results indicated that kalopanaxsaponin A has potential anti-tumor applications.