INHIBITORY EFFECT OF PRUNI CORTEX EXTRACT AND ITS COMPONENT, OCTACOSYL FERULATE, ON TUMOR PROMOTION BY 12-O-TETRADECANOYLPHORBOL-13-ACETATEIN 2-STAGE CARCINOGENESIS IN MOUSE SKIN

The methanol extract of Pruni Cortex inhibited tumour promotion by 12- O-tetradecanoylphorbol-13-acetate (TPA) in 7,12-dimethylbenz[a]anthrac ene (DMBA)-initiated mice. The active component was isolated from the methanol extract of Pruni Cortex. The active compound was characterize d as octacosyl ferulate by physical and chemical analysis. Octacosyl f erulate markedly inhibited the inflammatory activity induced by TPA in mice. The 50% inhibitory dose of octacosyl ferulate is 0.7 mg/ear on TPA-induced inflammation, Furthermore, octacosyl ferulate suppressed m arkedly the tumour-promoting effect of TPA on skin tumour formation fo llowing initiation with DMBA. Since protein kinase C (PK-C) was shown to be an intracellular target of TPA, effects of octacosyl ferulate on the activity of this enzyme were investigated. Octacosyl ferulate als o inhibited the phosphorylation of histon III-S by PK-C in a concentra tion dependent manner. (C) 1998 John Wiley & Sons, Ltd.