Evaluation of antimicrobial effects of different extracts and fractions of Marrubium parviflorum

Abstract

Introduction: The genus Marrubium have been used as a traditional medicine in the treatment of diseases from long time ago. Due to the daily use of medicinal herbs by people from all around the world, it is necessary and inevitable to examine these herbs more than before. Objective: Due to the medicinal importance of the genus Marrubium, M. parviflorum was selected to determine the antimicrobial activity of their extracts and fractions. Methods: The solvent extraction from aerial parts of the plant was performed by petroleum ether, chloroform and methanol using a soxhlet apparatus. Subsequently, the inhibitory activity of the extracts on the six strains of gram-positive bacteria and four strains of gram-negative, and one fungus (Candida albicans) was assessed qualitatively. Extracts with high growth inhibitory effect were evaluated by MBC method and also effective extracts were fractionated applying various chromatographic methods (VLC and SPE) and the amount of their MBC were evaluated. Results: The methanol extracts of M. parviflorum (with DIZ =11/3, 10/2 mm and MBC= 100 mg/ml) respectively against P. mirabilis and P. aeruginosa and the chloroform extract of M. parviflorum (with DIZ=16/6, 14/6, 11/6 and MBC=100 mg/ml) showed considerable antimicrobial activity. Between the fractions, 10%, 20%, 40% and 60% VLC fractions of chloroform and 20%, 40% SPE fractions of methanol extract of M. parviflorum illustrated the most bactericidal effect. Conclusion: chloroform and methanol extract of M. parviflorum indicated the most antimicrobial potency against M. luteus, S. epidermidis, B. cereus and P. mirabilis , and P. aeroginosa correspondingly.