Research on Antineoplastic Compounds Obtained from Natural sources Especially from Higher Plants
Vincristine and vinblastine isolated from Vinco spp. , and podophyllotoxine derivatives isolated from Podophyllum spp. are usefulas anticancerous components obtaned from higher plants. More thanten antineoplastic compounds are now following them as anticancerousagents from higher plants. In my laboratory, Sarcoma 180A has beenused as the first screening test. By this method, I have found outsome kinds of antineoplastic constituents from active plants extracts .For instance, bisaborane type compounds were isolated from Curcumaxanthorrhiza, one of Indonesian plants; a morphinane type compoundfromCocculus trilobus; cyclic hexapeptides from Rubia akane and R.cordiorta. Seven components having antineoplastic actirity wereisolated from Rubia spp. except. R. tinctoria. Their structures wereelucidated except RA-Vl by chemical reaction and variovs instrumentalanalysis as shown in Fig. Among of them, RA-Vll showed strong activityagainst P388 Lymphocytic leukemia, L2O, B16 melanoma, Lewis lungcarcinoma, colon 38 and Ehrlich carcinoma. RA-V revealed excellentactivity against MM2 mammary carcinoma. The· value of acute LD5O ofRA-ViI were 10. Omg/kg( iP) and 16.5mg/kg( po ) respectiveIy . Therapruticratio was 400, compared with 10 of mitomycin C. QSAR was also appliedto these compounds by elongation of ether and ester side chains atR'. Mechanism of action of RA-Vll was also investigated and wasassumed to be inhibition of protein biosynthesis .