Essential Oil Composition of Three Compositae- Aspillia africana, Chromolaena odorata, Syndrella nodiflora and One Labiatae- Hyptis suaveolens Plants Commonly Utilized as Rabbit Feeds

Abstract

Rabbits showed varied preferences in the order of their consumption of these four plants as meal: Syndrella nodiflora > Hyptis suaveolens > Aspillia africana > Chromolaena odorata. Chemical compositions with differences in levels of nutrients, palatability and odour may be responsible for the preferences observed. This study was targeted at examining volatile chemical constituents of both leaf and stem (parts utilized as meal) essential oils, which are likely responsible for the preferences observed. GC and GC-MS analyses conducted on eight essential oil samples revealed thus: Nine major compounds were responsible for 59.8 % of Syndrella nodiflora leaf essential oil. In its stem essential oil, twelve compounds which account for 40.5% of the oil were identified, these were dominated by terpenes (28.4%). Fifteen compounds were identified in leaf essential oil of the second preferred plant meal- Hyptis suaveolens, and was dominated by terpenes (61.3%), its most abundant compound being p-cineole (17.6%). Thirteen compounds make up 76.2% of its stem oil, two of which are yet to be identified; Seven (77.7%) and nine (75.7%) compounds were identified respectively in the leaf and stem volatile oils of Aspillia africana the third preferred plant meal. Its leaf oil is dominated by ?-bisabolol (46.4%), while terpenes make-up 70.4%. The stem oil has its most abundant compound to be (+) D-nerolidol (17.5%). Other interesting classes of compounds in the stem oil include hydrocarbons (23.5%), acid (9.1%) and alcohol (6.3%); Thirteen compounds each were identified in leaf and stem oils of Chromolaena odorata, the least preferred plant as meal by the rabbits, these compounds account for 57.3% and 72.3% of the oils respectively. Caryophyllene oxide (11.4%) is the dominant compound in leaf oil, while the stem oil is 3Z-3-heptadecen-5-yne (13.6%). Both oils are characterized with the dominance of terpenoids (45.4% and 47.3% respectively). Our results fully agree with compositions of the oils that have been reported in literature. This study presents compositions of stem essential oils of Syndrella nodiflora, Hyptis suaveolens and Chromolaena odorata for the first time.