Chemical Composition and Insecticidal Activity of Essential Oils of Four Varieties ofCodiaeum variegatum(L.) from Nigeria

Essential oils obtained by hydrodistillation of the air-dried leaves of four varieties of Codiaeum variegatum were analyzed by GC and GC-MS. The main constituents of C. variegatum (L.) Blume f. lobatum cv. Disraeli were caryophyllene oxide (58.2 %) and (Z)-β-farnesene (19.6 %). All the four compounds present in C. variegatum var. pictum ‘Congo’ namely linalool (39.3 %), 1,2,4-trimethylbenzene (21.0 %), β-pinene (21.6 %) and α-pinene (17.9 %) were present in significant amounts. Phytol (17.8 %), β-bisabolene (9.6 %) and linalool (8.9 %) were the major components of C. variegatum (L.) Blume f. taeniosum cv. Gold Sun, while, C. variegatum (L.) ‘Dreadlocks’ was dominated by β-ionone epoxide (29.7 %), γ-muurolene (20.5 %), naphthalene (16.3 %) and (E)- α-ionone (14.8 %). The chemical constituents of the studied essential oils were being reported for the first time. The essential oil displayed mortality (fumigant toxicity) against Sitophilus zeamais adults at tested concentration with lethal concentrations (LC50) of 72.07, 73.50, 47.43 and 44.04 μg/mL air respectively. The chemical constituents and insecticidal activity of essential oils of C. variegatum were being reported for the first time.