Inhibiting herpes simplex virus type 2 infection in human epithelial cells by gossypol, a potent spermicidal and contraceptive agent

Abstract

Gossypol, a male contraceptive, has an antifertility effect of 99.9%. It has also been reported to possess antiviral activities, and to inhibit herpes simplex virus infection in mice. Dorsett and Kerstine found that gossypol inactivated the infectivity of the enveloped virus parainfluenza type 3 and herpes simplex for HEp-2 carcinoma cells but had no effect on the infectivity of the nonenveloped poliovirus. The authors studied the effect of gossypol on infection by herpes simplex virus type 2 (HSV-2), the causative agent of herpes genitalis. In a series of experiments, gossypol and HSV-2 were added sequentially to confluent cultures of human amniotic epithelial cells and observed daily for cytopathic changes. No cytotoxicity was observed. Gossypol exerted a pronounced antiviral effect at 100 mcM; it totally inhibited the infection by 104 plaque-forming units (PFU); 10 mcM inhibited 100 PFU, and even 3 mcM caused some inhibition of HSV. Gossypol's antiviral effect is dose-dependent. The results clearly demonstrate the inhibitory effect of gossypol on HSV-2 infection; the doses used are comparable to or lower than the minimum effective antispermatozoal concentration of gossypol. Studies have reported the lack of toxicity of gossypol on normal cells and tissues, and its inhibiting effect on the growth of gonococci. Further studies should determine whether the antimicrobial effects of gossypol should be considered a favorable side effect in its use as a contraceptive, or whether gossypol has a value as an antiviral agent alone.