Evaluating the effect of Dracocephalum kotschyi methanol extract on Mycobacterium tuberculosis

Background and objectives: Tuberculosis (TB) is the major public health problem in the world. Each year there are 2-3 million deaths worldwide caused by TB. The increasing incidence of Multi Drug Resistance tuberculosis (MDR-TB) worldwide highlights the urgent need to search for new anti-tuberculosis compounds. It has been reported that medicinal plant, Dracocephalum kotschyi, possesses some antibacterial effect, thus in the present study its anti-mycobacterial property was evaluated. Methods: The sensitivity and resistance of M. tuberculosis strains at concentration of 0.2 µg/mL isoniazid was determined by proportion method. Methanol extract of D. kotschyi was prepared using maceration method. Six concentrations of D. kotschyi, including 20, 40, 80, 160, 320 and 640μg/mL were prepared and its anti-mycobacterial effect on four groups of M. tuberculosis including M. tuberculosis H37Rv (ATCC 27294), isoniazid susceptible and resistance and MDR strains was determined. Results: The methanol extract of D. kotschyi was significantly against M. tuberculosis. The percent of growthwas decreased from 100% to 0% in M. tuberculosis  H37Rv (ATCC 27294),  isoniazid resistant and isoniazid susceptible strains but from 100% to 50% in MDR strain in 640 μg/mL concentration. Conclusion: The results showed that different concentrations of D. kotschyi methanol extracts showed a remarkable inhibitory effect on M. tuberculosis. Identification of the effective fraction of D. kotschyi against M. tuberculosis is a further step to be studied.