Topical Effect of Mentha pulegium Essential Oil on Burn Wounds in Wistar rats

Introduction: Burn wound is a suitable place for the development of drug resistant infections. Therefore, investigations for effective drug development have a priority. The aim of this study was to identify the effects of herbal material on infectious burn wounds in rat. Materials and Methods: Mentha pulegium essential oil was prepared by a Clevenger apparatus. Sensitivity of clinical strain of Pseudomonas aeruginosa was determined by disk diffusion and microbroth dilution broth against the Mentha pulegium essential oil. Twenty-four Wistar rats were anesthetized by a mixture of ketamine and xylazine. Back of the rats were shaved and were burned by a molten metal. The fresh bacterial culture was inoculated on burn wounds by a cotton swap. Rats were divided into 3 equal groups. The first group was treated with essential oil, the second with silver nitrate ointment and the third group had no treatment. The wounds were evaluated for 25 days by calculating the area of the wound and microscopic examinations for infection symptoms, inflammation and histological examination. Results: Minimum inhibitory concentration of diluted essential oil was 5 mg/ml. In the treatment group with silver, many bacterial cells and inflammation signs were detected. In this group the rate of wound healing was low and due to inflammation it was not easily debrided. In the control group, the scar was formed without treatment, but the recovery rate was very low and the inflammation was proven. In both these groups, Pseudomonas was isolated successfully. Three rats in the silver group and all of rats in control group were dead during the test. In the test group with essential oil, the least inflammation and infection was observed. Culture result of the wound was Pseudomonas negative. The area of the wound in test group that treated by essential oil was 86.32% on 10th day and100% on 14th day. In the Silver group, the area of the wound was 36.124% on day 10 and 6.97% in the control group. Conclusion: It was concluded that, Mentha pulegium essential oil was able to control the infection and improve burn wound healing in Wistar rats. This material is recommended for the clinical trials on human.