Antimicrobial studies on three endemic species of Sideritis from Turkey

The antimicrobial activity of several extracts and fractions of some Sideritis species (S. albiflora, S. brevibracteata and S. pisidica) was investigated by disc diffusion and broth microdilution methods against Escherichia coli ATCC 11230, Staphylococcus aureus ATCC 6538P, Klebsiella pneumoniae UC57, Micrococcus luteus La 2971, Micrococcus flavus ATCC 14452, Proteus vulgaris ATCC 8427, Pseudomonas aeruginosa ATCC 27853, Corynebacterium xerosis CCM 7064, Mycobacterium smegmatis CCM 2067, Bacillus subtilis ATCC 6633, Bacillus cereus ATCC 9730, Kluyveromyces fragilis NRRL 2415 and Rhodotorula rubra CCY. The methanol extract and chloroform fraction of S. pisidica, as well as the methanol extracts, butanol and chloroform fractions of both S. albiflora and S. brevibracteata showed good antimicrobial activity against some bacteria and all yeasts tested, with growth inhibition area diameters in the range 10-20 mm, and MIC values between 0.03 and 0.38 mu l/ml. The results of the study support the use of these species in traditional medicine.