TUMOR-CELL GROWTH-INHIBITING EFFECT OF MELANOIDINS EXTRACTED FROM MISO AND SOY-SAUCE

gMelanoidins, a group of plant-produced melanins, were extracted from miso and shoyu (soy sauce), which are products of soybeans and widely consumed as food in oriental countries. The molecular weight of these melanoidins was approximately 5600 as revealed by Sepharose CL-4B colu mn chromatography. The melanoidins were cultured together with HCT-15 cells derived from human colon carcinoma and AGS cells derived from om human gastric carcinoma. Significant cell growth suppression was obse rved by incubating the cells with these melanoidins. The 50% growth su ppression dose ranged between 100 mu g/ml and 25 mu g/ml, that is, bet ween 2 x 10(-5) mM/ml and 0.5 x 10(-5) mM/ml. Flow cytometric analysis suggested that these melanoidins blocked the S phase and G2 to M phas e of the cell cycle.