Comparative studies of essential oil of fruit peels of four citrus species (family: Rutaceae) in Nigeria

Abstract

Comparative GCMS analysis was carried out on the essential oils of the fruit peels of four Citrus species: Citrus sinensis (Linn) Osbeck (Sweet orange), Citrus Limon (Linn) Osbeck (Lemon), Citrus paradise. Mactad (Grape fruit), and Citrus Aurantifolia (Christin) Swingle (Lime). Citrus Limon had 28 compounds identified, Citrus sinensis and Citrus paradise had 26 compounds each and Citrus aurantifolia had 21 compounds. The compounds were classified into monoterpenes, alcohols, aldehydes, ketones, esters, sesquiterpenes, oxides and other compounds. Monoterpenes were the predominant constituents in all the species studied and accounting for 72.83%, 68.75%, 57.19% and 49.35% for C. paradise, C. sinensis, C. aurantifolia and C. Limon respectively. Alcohols constituted 22.28% (C. aurantifolia), 18.57% (C. sinensis), 18.23% (C. Limon) and 12.23% (C. paradise). Aldehydes were 7.53% (C. Limon), 5.83% (C. sinensis), 5.62% (C. paradise) and 4.45% (C. aurantifolia). Sesquiterpenes gave 11.62% (C. Limon), 4.81 (C. paradise), 2.80 (C. aurantifolia) and 1.34% (C. sinensis). Oxides had 2.75% (C. aurantifolia), 2.50% (C. paradide), 1.38% (C. Limon) and 0.38% (C. sinensis). Ketones had 3.78% (C. Limon), 2.61 (C. aurantifolia), 2.21% (C. sinensis) and 0.00% (C. paradise). Esters had 3.97% (C. Limon), 0.91% (C. aurantifolia), 0.74% (C. sinensis) and 0.00% (C. paradise). Other components had 6.76% (C. Limon), 4.13% (C. aurantifolia), 1.35% (C. paradise) and 1.20% (C. sinensis). The major compounds found in all the Citrus species were: Limonene, alpha terpineol, alpha pinene, beta-pinene, beta-linalool, lemonol, alpha and beta citral. These various bioactive constituents idenfied in Citrus species have a wide spectrum of applications in the pharmaceutical industry and as flavoring agents in the manufacture of perfumes and cosmetics and as flavoring agents in the manufacture of perfumes and cosmetics.