Growth Inhibitory Activity of Gossypol Against Several Trichomonas vaginalis Isolates

Abstract

We report an in-vitro inhibitory effect of gossypol on eight Trichomonas vaginalis isolates. Metronidazole is an effective medication against T. vaginalis, but there is an increasing number of reports of Trichomonas resistance to the drug. Subsequently, alternative therapies need to be investigated. The pharmacological properties of gossypol have been studied extensively because of its toxicity to livestock, its antifertility effects in man, and its activity against diverse pathogenic agents. Eight T. vaginalis isolates were treated with either variable concentrations of gossypol (0-100 μm) or metronidazole (0-1.0 μM). The effective IC50 range for gossypol was from 24.39 to 38.77 μM (metronidazole: 0.15-0.40 μM) with an average of 31.9 μM (metronidazole: 0.27 μM). No gossypol-resistant Trichomonas strains were detected. Gossypol, formulated as pesky, is used safely and successfully as an antifertility drug in man. The effective spermicidal dose of this drug (50 μM), and the antitrichomonas IC50 doses are comparable. This polyphenol also has a clear inhibitory effect against herpes and human immunodeficiency virus. Its effectiveness as an antitrichomonic medication could be immediately evaluated, considering that this drug is already used in man. Since gossypol is an abundant by-product of the cottonseed industry, it may be produced at relatively low cost.