Chemical composition and biological activities of essential oils of Azadirachta indica A. Juss.

Abstract

Summary. Essential oils of Neem, Azadirachta indica A. Juss. (family Meliaceae) leaves and flowers were prepared by hydrodistillation method. The chemical composition of the oil samples was investigated by GC/MS. Hydrocarbon constituted 85.36% of the leaves oil .The major compounds were β-Elemene (33.39%), γ- Elemene (9.89%), Germacrene D (9.72%), Caryophyllene (6.8%) and Bicyclogermacrene (5.23%) while the percent of the oxygenated compounds were (5.04%) mainly attributed to sesquiterpene oxide. On the other hand, flowers oil hydrocarbons constituted 63.22% composed mainly of pentacosane (18.58%), tetracosane (10.65%), β-germacrene (9.73%), β- caryophyllene (5.84%) and dodecene (4.54%) while the percent of the oxygenated compounds were 28.3% mainly attributed to octadecanol (16.7%), verdiflorol (5.32%), farnesol (1.63%) and α– terpineol (1.51%). The antioxidant properties determined by 2, 2-diphenyl-1-picrylhydrazyl assays, antibacterial activity against Gram-positive and Gram-negative, antifungal and larvicidal activities were promising and in relation with the chemical composition of the essential oils. The results indicated that essential oil of flowers could be especially promising as an inexpensive source of effective antioxidant /antimicrobial /larvicidal agents tantamount to fixed oil of the neem seeds.

Industrial relevance. The use of medicinal plants is a universal phenomenon. Natural products from plants are rich source to identify, select and process new drugs for medicinal use. Most of research focused on fixed oil of neem seeds but very little was concerned about volatile oils of leaves and flowers. The diverse biological activities of Neem essential oils can be applied on a large scale as antioxidant, antimicrobial and larvicidal agents comprising many important benefits including their volatility, lower level of risk to the environment than with synthetic ones.

Keywords. Azadirachta indica; Neem; essential oil; GC/MS; antioxidant; antibacterial; antifungal; larvicidal.