GC-MS Analysis and Antioxidant Activity of the Essential Oil Constituents from the Dried Leaves of <i>Gossypium arboreum</i> LINN

The name 'cotton plant' is actually used for four species in the genus Gossypium: G. birsutum L. barbadense L. G. arboreum L. G. berbaceum L. Alongside with their economic importance, the leaf, root, bark and seeds of Gossypium species have been widely explored for their medicinal values. G. arboreum possess wound healing and antioxidant properties. This study aims is to extract the essential oil of the dried leaves of Gossypium arboreum, determine the oil constituents, and assess the potential antioxidant activities of the oil. The essential oil from 150 g of air-dried leaves of Gossypium arboreum was obtained by hydrodistillation method in a Clevenger-type set up. The chemical constituents of the essential oil were analyzed by Gas chromatography coupled with mass spectrometry (GC-MS). The antioxidant activity of the essential oil was also evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) as the reagent and ascorbic acid as the standard. Results obtained was colourless and have a strong odour which was peculiar to the plant with a percentage yield of 0.05%. Twenty eight constituents representing 100% of the oil were identified from the GC-MC spectra. The major components of the essential oil were n-hexane (28.32%), 2-ethyloxetane (25.26%), pentane, 3-methyl (18.50%), and cyclopentane methyl (14.36%). Aliphatic hydrocarbon (66.25%), monoterpene hydrocarbons (3.21%), sesqueterpenoids (0.44%, oxygenated monoterpene (0.08%) and organosilicon compounds (0.38%) were the classes of compound found in the oil. Antioxidant activity at 517m of the essential oil of G. arboreum was investigated and the essential oil showed 71.70%, 81.53%, and 88.22% inhibition at concentrations 0.1, 0.2 and 0.3 mg/mL respectively. In conclusion, some of the oil constituents such as limonene, γ-terpinene, and caryophyllene that are present in G. arboreum has its medicinal uses.