[Antimicrobial effects of methanolic extracts of some species of stachys and phlomis]

ABSTRACT

The genus Phlomis and Stachys [Labiatae] are widely distributed in Iran. There are no reports on the antimicrobial activity of some of these plants. The medicinal properties attributed to the genus Phlomis and Stachys prompted us to investigate the antimicrobial activity of the methanolic extracts of Phlomis bruguieri, P. herba-venti, P.olivieri, Stachys byzantina, S. inflate, S. lavandulifolia and S. laxa. The antimicrobial activity of these plants were studied using the disc diffusion methods [10,50, 100, 250, 500, 750, and 100 micro g/disc] and determination of minimum inhibitory concentration [MIC] values [10 micro g/ml to 25 mg/ml] against Staphylococcus aureus PTCC 1112, Streptococcus sanguis PTCC 1440, Escherichia coli PTCC1330, Pseudomonas aeroginosa PTCC 1074, Klebsiella pneumoniae PTCC 1053, Aspergilus niger PTCC 5011 and Candida albicans PTCC 5027. The methanolic extracts of the aerial parts of Phlomis bruguieri, P. herba-venti, P. olivieri, Stachys byzantina, S. inflate, S. lavandulifolia and S. laxa exhibited concentration-dependent antibacterial activity against all tested bacteria. The methanolic extracts were more active against Gram-positive microorganisms [Streptococcus sanguis and Staphylococcus aureus]. The extracts did not show any antifungal activity. The results concluded that the methanolic extracts of these plants have a potential source of antibacterial of natural origin