Synergistic antibacterial activity between Thymus vulgaris and Pimpinella anisum essential oils and methanol extracts

Essential oils (EOs) and methanol extracts obtained from aerial parts of Thymus vulgaris and Pimpinella anisum seeds were evaluated for their single and combined antibacterial activities against nine Gram-positive and Gram-negative pathogenic bacteria: Staphylococcus aureus, Bacillus cereus, Escherichia coli, Proteus vulgaris, Proteus mirabilis, Salmonella typhi, Salmonella typhimurium, Klebsiella pneumoniae and Pseudomonas aeruginosa. The essential oils and methanol extracts revealed promising antibacterial activities against most pathogens using broth microdilution method. Maximum activity of Thymus vulgaris and Pimpinella anisum essential oils and methanol extracts (MIC 15.6 and 62.5 μg/ml) were observed against Staphylococcus aureus, Bacillus cereus and Proteus vulgaris. Combinations of essential oils and methanol extracts showed an additive action against most tested pathogens especially Pseudomonas aeruginosa.