Chemical composition of essential oil of Tithonia diversifolia (Hemsl.) A. Gray from the Southern slopes of Mount Elgon in Western Kenya

Abstract

Ethnopharmacologically, Tithonia diversifolia has a lot of applications in the history of human life. The current study aimed at characterizing the essential oil from fresh aerial parts of T. diversifolia. The plant materials were obtained from western Kenya and oil extracted by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Compounds were identified by comparison of their mass spectra with those in Wiley NBS and NIST databases and GC retention times to those of authentic samples. The percentage yield of the essential oil of T. diversifolia was 0.00015% w/w. The oil showed a complex composition of about 50 compounds, a mixture of monoterpenes and sesquiterpenes, 54% and 46%, respectively. Within the sub-classes of terpenes, hydrogen-carbon-containing terpenes (72%) occurred more than oxygencontaining terpenes (28%) with hydrogen-carbon-containing sesquiterpenes (38%) occurring in the highest proportion, followed by hydrogen-carbon-containing monoterpenes (34%), oxygenated monoterpenes (20%) and oxygenated sesquiterpenes (8%). Twenty-four percent of the 50 compounds and most of the monoterpenes were found in literature to have some repellence properties. Of these 50 compounds, α-pinene occurred in the largest amount (63.64%), followed by β-pinene (15.0%), isocaryophyllene (7.62%), nerolidol (3.70%), 1-tridecanol (1.75%), limonene (1.52%), sabinene (1.00%), α-copaene (0.95%), αgurjunene (0.56%) and cyclodecene (0.54%). With multipotential applications nature of T. diversifolia plant and its products, these compounds may in future be useful in pharmaceutical, agricultural, food and perfumery industries.