Gramicidin, a polypeptide antibiotic derived from Bacillus brevis, was compared in vitro with the established contraceptive virucidal agents nonoxynol-9 and gossypol for activity against human immunodeficiency virus (HIV) infection. The effective antiviral 10 ng/ml concentration of gramicidin required for complete HIV inactivation was a thousand-fold lower than the dose observed for nonoxynol-9 or gossypol. Gramicidin, routinely used as a contraceptive agent in the former Soviet Union, should be considered for in vivo trials as a spermicide with potent antiviral activity.
PIP: At the New York University Medical Center, researchers used an antiviral assay, p24 ELISA, and cytoxicity assays to compare the antiviral activity of the newly-discovered anti-HIV compound gramicidin with established spermicides that have demonstrated antiviral activity. A 10 ng/ml of gramicidin completely inhibited productive HIV infection in MT-4 lymphocytes, while a 1000-fold higher dose of nonoxynol-9 and gossypol (10 mcg/ml) was needed to achieve the same effect. A possible mechanism is impaired permeability for cations, resulting in inhibition of virus-induced fusion. The study did not try to determine the biochemical mode of gramicidin action, however. Gramicidin is used in the former USSR as an active component of spermicidal gels and foams and as a topical, non-irritating antibiotic often used to treat ocular infections. The results of this in vitro study call for more in vitro studies to determine the biochemical mechanism of gramicidin action and its clinical potential as a vaginal spermicide with antiviral activity.