CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITIES OF THE ESSENTIAL OILS OF LIPPIA ADOENSIS HOCHST ex. WALP AND OCIMUM SANCTUM LINN

Abstract

Essential oils of Lippia adoensis Hochst ex. Walp leaf, Ocimum sanctum Linn leaf and stem and mixture of two plants from Bishoftu and Debre Berhan (Ethiopia) were analyzed using gas chromatography-mass spectrometry. The essential oil of O. sanctum from Bishoftu showed 12 compounds with major components being-bisabolene (31.38%), 4-[(1Z)-1,5-dimethyl-1,4-hexadien-1-yl]-1-methylcyclo-hexen (25.56%), eucalyptol (17.12%). While that from Debre Berhan contained 20 compounds with major components being-bisabolene (24.45%), 4-[(1Z)-1,5-dimethyl-1,4-hexadien-1-yl]-1-methylcyclohexen (19.61%) and eucalyptol (13.42%). The essential oil of the leaves of Lippia adoensis from Bishoftu showed 15 compounds with major components as linalool (66.60%), caryophyllene (4.28%) and that from Debre Berhan showed 12 compounds with linalool (86.11%) as major compound. The essential oil of the mixture of L. adoensis and O. sanctum from Bishoftu showed 18 compounds with major compound being linalool (62.54%) and that from Debre Berhan showed 21 compounds with major compounds being linalool (48.47%) and eicosane (9.42%), octadecane (5.47%). The essential oils of O. sanctum and L. adoensis and their mixture from the two places exhibited DPPH radical scavenging activity of 96.48% and 96.17%, 92.58% and 93.37%, and 95.25% and 96.42% at 100 µg/mL, respectively. The antioxidant activities of essential oils were comparable to that of ascorbic acid which exhibited 98.08% at the same concentration (100 µg/mL).