CHEMOPREVENTION AND THERAPY OF CANCER BY D-LIMONENE

The naturally occurring monoterpene d-limonene has chemopreventive and chemotherapeutic activity against many rodent solid tumor types. The chemopreventive activity of limonene during initiation can be attribut ed to the induction of phase I and phase II enzymes, with resulting ca rcinogen detoxification. The chemopreventive activity of limonene duri ng promotion/progression may be due in part to inhibition of the postt ranslational isoprenylation of growth-controlling small G proteins, su ch as p21ras. The complete regression of mammary carcinomas by limonen e appears to involve tissue redifferentiation. The multiple antitumori genic effects of limonene are attainable at a high therapeutic ratio, suggesting that limonene and related monoterpenes may be efficacious i n the chemoprevention and chemotherapy of human malignancies.