Antimicrobial Activity and Gas Chromatography-Mass Spectrometry (GC-MS) Analysis of Saudi Arabian Ocimum basilicum Leaves Extracts

Abstract

The present study evaluates the antimicrobial activity of Ocimum basilicum leaves extracts using well diffusion assay. Microbicidal or Microbiostatic activities were determined using (MBC or MFC) /MIC ratio. All O. basilicum extracts ethanol, methanol, and water possess antimicrobial activity. Methanol was the best solvent with greater inhibitory activity followed by ethanol then water against bacteria. However, all three solvents showed no difference in their inhibitory activity against yeast. The MIC and MBC values were in decreasing order methanol, ethanol then water against bacteria whereas Candida albicans was more sensitive at MIC 12.5µg/mL than C. tropicalis at MIC 25µg/mL and MFC values were lower against C. albicans than C. tropicalis at 25µg/mL and 50µg/mL, respectively in all type of solvents. The ratio of (MBC or MFC) /MIC were one to three-folds. The GC-MS result showed the presence of several important chemical compounds like terpene, steroids, phenols, esters, and fatty acids most of these compounds were reported to have an antimicrobial activity. The study indicates the importance of O. basilicum extracts as microbicidal agent with wide spectrum and high inhibitory properties in low concentrations. Therefore, O. basilicum leaves extracts may be important in the field of antimicrobial production as alternatives to antibiotics.