Owokotomo. I.A. , Jabar. J.M, Abata, E.O.

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Essential oils are plants’ secondary metabolites widely used through ages for bactericidal, fungicidal, anti-parasitic and insecticidal applications. In recent years, there has been an increased interest in essential oils because of their potentials as pharmaceuticals. However, there is a dearth of information on the antioxidant activity of the essential oils from Aframomum melegueta, Crassocephalum crepidioides, Monodora myristica and Ocimum gratissimum from Nigeria. This study was designed to screen the essential oils from these plants for possible radical scavenging (antioxidant) activity. Essential oils were extracted from the leaves, stem-bark, roots and seeds of the plants through hydro-distillation using the Clevenger type apparatus. The oils were analysed by gas chromatographic and gas chromatographic/mass spectrophotometric techniques. The essential oils were composed of monoterpenoids and sesquiterpenoids. They were tested for antioxidant activity using 1-diphenyl-2-picrylhydrazyl (DPPH) method. The antioxidant activity ranged from 65.5 to 96.4%. Essential oils of O. gratissimum leaves exhibited the highest antioxidant activity (96.4%). The results obtained suggest possible applications of the essential oils from these plants as sources of pharmaceuticals. Keywords: Medicinal plants, Essential oils, Antioxidant activity, Nigeria