In vitro and in vivo antibacterial activity of Pogostone

Background Our pervious antibacterial studies on several traditional Chinese medicines have found that Patchouli oil from Pogostemon cablin had significant antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), which has spread worldwide and infected innumerable people. In order to find the more active natural substances in Patchouli oil, one of the major components, Pogostone, was isolated and its antibacterial activity was evaluated in vitro and in vivo in this study. Methods In vitro test, Pogostone was screened for antimicrobial properties against 83 bacteria comprising 35 gram positive and 48 gram negative bacteria strains via the agar double dilution method. In vivo test, specific pathogen free (SPF) strain of both male and female white Kunming mice, weighing 18-22 g, were used to test the protective ability of Pogostone after being injected with the median lethal doses (MLDs) of the tested strains. Results In vitro test, Pogostone could inhibit both gram negative bacteria (0.098-1 600 mu g/ml) and gram positive bacteria(0.098-800 mu g/ml). For Corynebacterium xerosis and some Chryseobacterium indologenes, the minimum inhibitory concentration (MIC) values of Pogostone were extremely low (<0.098 mu g/ml). It was significant that Pogostone was also active against some drug-resistant bacteria like MRSA. Furthermore, Pogostone showed antibacterial activity in vivo against Escherichia coli (E. coli) and MRSA via intraperitoneal injection. Ninety percent of the mice infected with E. coli could be protected at the concentrations of 50 and 100 mg/kg, and 60% of the mice at 25 mg/kg, while the rate of protection for the mice infected with MRSA was 60% and 50% at doses of 100 and 50 mg/kg, respectively. Conclusion Pogostone could be developed as a potential antibacterial agent for clinical therapy.