Comparative analyses of phytochemical composition and antimicrobial properties of different solvent extracts of Melissa officinalis leaves

Abstract

Aim : The ethanol, methanol, hexane, chloroform, isopropanol and water extract of Melissa officinalis leaves were tested for antimicrobial activity against eleven bacteria and one yeast by disc diffusion method. Methodology The antimicrobial activity was assessed and the volatile components of chloroform and dimethyl sulfoxide extracts of Melissa officinalis leaves were analysed by GC/MS. Results : In the present study, chloroform extracts of Melissa officinalis leaves showed the best inhibition zone (27 mm) against Candida albicans. Inhibition zones of the all the extracts varied from 8 to 27 mm against tested microorganisms. The minimum inhibitory concentration (MIC) of M. officinalis subsp. officinalis extracts obtained by broth serial dilution method, chloroform extracts were among the most active with the MIC values ranging from 0.016-128 mg ml(-1). C. albicans showed lowest sensitivity to 0.016 mg ml(-1) concentration of chloroform extracts. GC/MS analyses of dimethyl sulfoxide extracts identified three compounds; the primary content of lemon balm leaves extract was dimethyl sulfoxide (98.53%). Similarly, GC/MS analyses of chloroform extract identified eight compounds; the primary contents of the of lemon balm leaves extract were chloroform (96.6%). Interpretation : Different solvent extracts of Melissa officinalis leaves showed a broad-spectrum activity against both Gram-positive and Gram-negative bacteria and fungi. Chloroform and dimethyl sulfoxide extracts, especially showed better antimicrobial activity due to high content of chloroform and dimethyl sulfoxide. [GRAPHICS] .