Evaluating the effect of Dracocephalum kotschyi methanol extract on Mycobacterium tuberculosis

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.

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.

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.

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.