Chemical Composition and Antioxidant Activity ofOcimum basilicumL. Essential Oil Cultivated in Madinah Monawara, Saudi Arabia and its Comparison to the Egyptian Chemotype

The chemical composition of Ocimum basilicum L. essential oil obtained from Egypt and Al Madinah Al Munwara, Saudi Arabia were analyzed using Gas chromatography-Mass spectrometry (GC-MS). Fifty-six components represented 96.33% were identified in the essential oil of Egyptian herb, while 65 components detected in Madinah oil with 92.17% of the chromatographic peak area. Methyl chavicol (27.82%) and linalool (25.35%), were found to be the dominant constituents in Egyptian Ocimum basilicum L. (methylchavicoal-linalool chemotype), however eugenol (25.85%) and linalool (13.41%) were the major component in the essential oil of Madinah herb (eugenol-linalool chemotype). The antioxidant activity was investigated, where different assays were used namely scavenging of the biphenyl picrylhydrazyl radical (DPPH) and β-Carotene / linolelic bleaching as well as measuring the total phenolic for both essential oils. The essential oil of Egyptian Ocimum basilicum L. showed higher antioxidant activity with IC50 0.21 mg/ml, in comparison to Madinah chemotype IC50 4.04 mg/ml, which was attributed to the significant differences in chemical constituents and in accordance to the total phenolic content for both herbs. Egyptian Ocimum basilicum L. oil revealed a remarkable antioxidant activity 86.9% compared with known synthetic antioxidant, TBHQ (98.8%).