THERAPEUTIC SUBSTANCES

Extracts of Cimicifuga racemosa (L.) Nutt. (syn.: Actaea racemosa L.) (CR) inhibit the proliferation of the human prostate cancer cell line LNCaP. Recently, the phenylpropanoid ester 3,4-dihydroxyphenacyl caffeate (petasiphenone, 1) was isolated from CR. This substance is a structural homologue to petasiphenol ([3-(3,4-dihydroxyphenyl)-2-oxopropyl caffeate]), a compound produced by Petasites japonicus Sieb. & Zucc. which inhibits the growth of various human leukemia cell lines. Because of the structural similarity, we examined whether 1 affects the proliferation of LNCaP cells and the secretion of prostate-specific antigen (PSA). Under basal conditions as well as under co-incubation with 10 nM estradiol [E2 or 1 nM dihydrotestosterone (DHT)], 1 dose-dependently inhibited proliferation of LNCaP cells while PSA release per cell was not altered. We report for the first time that a defined compound isolated from CR inhibits the growth of the human prostate cancer cells LNCaP.