The aim of this study was to evaluate the antimicrobial activity of extracts from olive and basil leaves against some selected pathogenic bacterial and fungal isolates.
Patients and methods
Methanolic/chloroform extract of olive and methanolic extract of basil leaves were prepared and their antimicrobial activities were tested against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Klebsiella spp., and Candida spp. using the agar well-diffusion method. High-performance liquid chromatography was performed for analysis of phenolic compounds and gas chromatography and mass spectrometry for volatile oils. PCR and sequencing was performed for identification of gene ERG11 of resistant and sensitive strains of Candida tropicalis to fluconazole. Reverse transcriptase (RT)-PCR was performed to detect gene expression.
The antimicrobial activity of basil extract was stronger than that of olive. The main phenolics were oleuropein for olive and rosmarinic for basil and the main volatile oils were triterpene for olive and linalool for basil. RT-PCR proved the expression of ERG11 gene by the resistant strain only.
Basil has a stronger antimicrobial activity compared with olive. It varies with different strains, being the best against S. aureus and Pseudomonas spp. Phenolics, mainly oleuropein, rosmarinic, and caffeic acid, had antimicrobial activity. Expression of ERG11 gene might be responsible for the resistance of C. tropicalis to fluconazole. In-vivo experimental study for the antimicrobial activity is recommended.