Effect of Seasonal Variation on the Chemical Composition of Leaf Essential Oil of <i>Aframomum Latifolium </i>(K. Schum) Obtained from Southwest Nigeria

Abstract

This study was aimed at investigating effect of seasonal variation on yield and chemical composition of leaf essential oil of <i>Aframomum Latifolium</i> over a period of twelve months. Fresh leaves of this plant were subjected to hydrodistillation every month for a period of twelve months using an all glass Clevenger apparatus. The volatile oil obtained each month was analyzed by means of gas chromatography/mass spectrometry (GC/MS). The percentage oil yield ranged between 0.03 – 0.15 % v/w for the twelve treatments. Twenty compounds were identified in the volatile leaf oil obtained over a period of twelve months and oxygenated monoterpene was the most dominant constituent. Cajeputol, an oxygenated monoterpene has the highest percentage in the twelve treatments (39.40 – 45.61%). The effect of seasonal variation was established in the yield of the volatile oil in this study as the maximum yield (0.11%) (v/w) was recorded in November. There is a sudden disappearance of limonene in august and September and a rise in the level of cajeputol between august and November. The volatile oils obtained were rich in cajeputol (45.61%) and α-pinene (20.97%) and these compounds had been documented to be a cough suppressant, anti-inflammatory and anti-microbial agents.