IDENTIFICATION OF A PROSTATE INHIBITORY SUBSTANCE IN A POLLEN EXTRACT

Recently, much attention has focused on the treatment of BPH with the pollen extract, Cernilton. The present investigation was designed to i dentify the active component in this agent which might be responsible for the symptomatic relief of BPH as previously reported [1,2]. Sequen tial purification of the active component present in the pollen extrac t was carried out by a combination of dialysis, gel filtration, and re verse phase chromatography. To monitor the biological activity of each of the purified fractions, a biological assay employing the human pro state cancer cell line DU145 was undertaken. While we have identified a number of constituent components in the pollen extract, only one fra ction designated V-7 (FV-7) maintained a strong inhibitory effect on t he growth of DU145 cells. The inhibition was time- and dose-dependent, and the concentrations of FV-7 required to reduce the cell numbers by 50% (IC50) after 2 days of exposure was 5 mu g/ml. FV-7 was also inhi bitory towards the primary culture of prostate stroma and epithelial c ells, with the stroma/fibroblast showing greater sensitivity towards t he HPLC-purified component. However, it should be noted that this inhi bitory activity measured in the primary culture cells was only achieve d at higher concentrations of FV-7. Preliminary characterization of th e active ingredient identified FV-7 as DIBOA which is a cyclic hydroxa mic acid. FV-7 and DIBOA induce similar inhibitory effects on the grow th of DU145 cells. (C) 1995 Wiley-Liss, Inc.