By using cultured mouse fibroblast cells transformed with Simian virus 40 which bears the putative oncoprotein-oncosuppressor system, the rice bran was shown to contain anti-cancer substances which are selectively cytotoxic to the SV40-transformed cells but not to the non-transformed counterpart cells. Active substances were found in a small molecular fraction between the molecular weights of 500 and 1,000 dalton, as revealed by molecular sieve chromatography on a Bio-gel P-2 column. LD50 and LD90 value of the active fraction was 1.0mg/ml and 3.0mg/ml to SV40-transformed cell, respectively, wheras at these concentrations nearly no cytotoxicity was observed to nontransformed cells.
