Geraniol, a component of plant essential oils, inhibits growth and polyamine biosynthesis in human colon cancer cells

Geraniol and other monoterpenes found in essential oils of fruits and herbs have been suggested to represent a new class of agents for cancer chemopre vention. As a first step in clarifying the mode of action of geraniol on co lon carcinogenesis, we studied its effects on the growth of a human colon c ancer cell line (Caco-2). Geraniol (400 muM) caused a 70% inhibition of cel l growth, with cells accumulating in the S transition phase of the cell cyc le, and concomitant inhibition of DNA synthesis. No signs of cytotoxicity o r apoptosis were detected. Geraniol caused a 50% decrease of ornithine deca rboxylase activity, a key enzyme of polyamine biosynthesis, which is enhanc ed in cancer growth. This led to a 40% reduction of the intracellular pool of putrescine. Geraniol also activated the intracellular catabolism of poly amines, indicated by enhanced polyamine acetylation. These observations ind icate that polyamine metabolism is presumably a target in the antiprolifera tive properties of geraniol.