Chemical composition and antibacterial activity of essential oil isolated from Omani basil (Ocimum basilicum Linn.)

To identify the major volatile constituents and evaluate the antibacterial activity of essential oil isolated from the aerial parts of Ocimum basilicum (O. basilicum) Linn. grown in Oman. The fresh plant material was collected in the month of September from Seeb Nursery in Muscat Governorate, Sultanate of Oman. The aerial parts of O. basilicum Linn. were separated from fresh plant and essential oil was isolated by hydrodistillation method by using Clevenger apparatus. A greenish yellow oil was obtained in 0.6% v/w yield which was analyzed by gas chromatography–mass spectrometry for its chemical composition. The antibacterial activity of oil was also evaluated against three Gram–positive and four Gram–negative pathogenic bacterial strains by agar well diffusion method. A total of thirty six chemical constituents were identified and linalool (69.87%) was found to be the major constituent. Other main identified constituents included geraniol (9.75%), p-allylanisole (6.02%), 1,8–cineole (4.90%), trans–α–bergamotene (2.36%) and neryl acetate (1.24%). The essential oil of O. basilicum showed excellent antibacterial activity against Gram–positive bacteria and moderate activity against Gram–negative bacteria. Omani basil is characterized by a high content of linalool which makes it useful in food, pharmaceutical and perfumery industries.