Evaluation of essential oil from tulsi (Ocimum sanctum L) grown in Egypt: Chemical changes and antimicrobial activity during storage of tulsi oil

In order to introduce new species of medicinal and aromatic plants into Egypt, the seeds of tulsi (Ocimum sanctum L.) (origin: USA) were subjected to propagation and cultivation in Egypt. The essential oil was obtained by hydrodistillation of the herb during the full blooming stage. The oil was subjected to different storage conditions. It was stored at three different temperature conditions, i.e. room temperature, refrigerating (4–0°C) and deep freezing (-17°C). The chemical composition of the oil was analyzed by means of GC and GC/MS [1]. In addition to the already known Eugenol (24.9%) and β-bisabolene (16.3%) as the main constituents of the oil [2], other compounds were identified. Terpenic constituents showed variable responses to storage conditions, some terpens increased while others decreased. The profound deterioration was obtained when the oil was stored at room temperature. The tulsi oils were subjected to biological assays [3] (three bacteria, two fungi and two yeasts). The antimicrobial activities of the essential oils were evaluated out using the inverted petriplate method [3]. The most important finding is the high potency of tulsi oils against fungi compared with Gram (±) bacteria and yeast strains.

References: [1] Adams, R. P..(1989) Identification of Essential oils by Ion Trap Mass Spectroscopy. Academic Press, New York. [2] Ibrahim M. E. (1999) Physiological and Chemical Studies on Tulsi Plant (Ocimu sanctum). Egypt. J. Hort 26 (2), pp.147–165. [3] Bauer, J.D. (1982). Clinical Laboratory methods. P. 832. 9^th Ed. The C.V. Mosby Co. St. Louis Toronto Landon. [3] Collins CT, & Lyne PM. (1985). Micrbiological Methods. 5th ed, (pp 167–181), Butterworth and Co Pub Ltd, London and Toronto.