In vitro activity of eugenol, an active component from Ocimum sanctum, against multiresistant and susceptible strains of Neisseria gonorrhoeae.

In view of the widespread emergence of resistant isolates, an attempt was made to isolate and characterise the component(s) of Ocimum sanctum with activity against Neisseria gonorrhoeae. Bioassay-guided purification of the hexane extract of leaves of O. sanctum was carried out, which yielded H12c as the active compound. H12c was characterised and was determined to be eugenol, with a minimum inhibitory concentration of 85-256 mg/L. The antigonorrhoeal efficacy of H12c was better against multiresistant strains. The 50% lethal dose (LD50) of H12c was found to be 2g/kg body weight in rats. In view of its efficacy and lower toxicity, eugenol may be a potentially suitable molecule to be developed clinically in response to emerging resistant isolates of N. gonorrhoeae.