标题：POTENT IMMUNOSUPPRESSIVE PRINCIPLES, DIMERIC SESQUITERPENE THIOALKALOIDS, ISOLATED FROM NUPHARIS RHIZOMA, THE RHIZOMA OF NUPHAR PUMILUM (NYMPHAEACEAE) : STRUCTURE-REQUIREMENT OF NUPHAR-ALKALOID FOR IMMUNOSUPPRESSIVE ACTIVITY
摘要：Potent immunosuppressants, the dimeric sesquiterpene thioalkaloids, 6-hydroxythiobinupharidine (2), 6, 6'-dihydroxythiobinupharidine (3), 6-hydroxythionuphlutine B (5) and 6'-hydroxythionuphlutine B (6), were isolated from a natural medicine, Nupharis Rhizoma, the rhizoma of Nuphar pumilum (TIMM.) DC., through bioassay-guided separation together with five quinolizidine alkaloids (8, 9, 10, 11, 12). Dimeric sesquiterpene thioalkaloids (2, 3, 5, 6) were found to significantly inhibit anti-sheep erythrocyte plaque forming cell formation in mice spleen cells at 10-6 M concentration. At this concentration, 2, 5 and 6 were found to exhibit no cytotoxicity to mice spleen cells, and 3 also showed only a little cytotoxicity. In addition, the inhibitory activity of several Nuphar alkaloids, dimeric sesquiterpene thioalkaloids (1, 4, 7, 8), and monomeric sesquiterpene alkaloids (9, 10, 11, 12) on anti-sheep erythorocyte plaque forming cell formation was examined and some structural requirement of Nuphar alkaloid for immunosuppressive activity was determined.
