Chemical profiles of essential oils of Croton dichogamus and Croton megalocarpus from Elkeiyo Marakwet, Kenya

Abstract

Essential oils are rich in bioactive compounds which generally contribute to the overall medicinal value of plant species. Euphorbiaceae plants are mostly used by the traditional herbalists to treat different kinds of ailments. This work was aimed at determining the chemical profiles of Croton dichogamus and Croton megalocarpus. The leaf essential oils were extracted using hydro-distillation in a modified Clevenger apparatus. Gas-chromatography and mass spectrometry was used to determine the chemical constituent of essential oils. Among the major monoterpene hydrocarbons identified from Croton dichogamus were β-terpinene (42.19%), p-cymene (5.05%), α-pinene (4.04%), (β-pinene (2.45%), β-terpinene (2.42%) and limonene (5.05%), sesquiterpenes identified were (E)-caryophyllene (1.38%), α-humulene (1.20%) and α-curcumene (1.82). Oxygenated monoterpenes present were linalool (3.59%), 2-bornanone (2.44%), terpinen-4-ol (10.09%), α-terpineol (1.04%) and terpinen-4-ol (10.09%). Major compounds identified from Croton megalocarpus, included monterpenes; α-pinene (8.04%), sabinene (6.93%), β-pinene (24.62%), o-cymene (4.58%), sesquiterpene (E)-caryophyllene (7.09%) and oxygenated sesquiterpene caryophyllene oxide (7.09%). α-Humulene (0.08-1.58%), α-pinene (1.38-26.20%), α-cubebene (0.03- 0.6%) and caryophyllene oxide (0.24-7.09%) were identified in all the essential oils of plants used in this study. The presence of oxygenated monoterpenes and sesquiterpenes suggests that the essential oils could be effective in managing secondary infections.