Title : Phytochemical profile and antioxidant activity of essential oil from fresh and dried leaves of wedelia trilobata
The accumulation of free radicals in the human body often results to oxidative stress. This is a condition that leads to the damage of cells alongside the process of aging, necessitating its removal from the body. Synthetic antioxidants such as butylatedhydroxytulene (BHT), butylatedhydroxyanisole (BHA) are good free radical scavengers but are associated with side effects as; vomiting, tumor and nausea when used in the human body, in addition, they are expensive. Essential oils of plants and fruits have demonstrated promising antioxidant property, these antioxidant properties of the oil are attributed to the presence of the compounds; pinene, carvacrol, limonene, geraniol and other secondary metabolite which may also be present. The essential oil from leaf of Wedelia trilobata obtained from Makurdi Benue State of Nigeria have not been used to curtail the oxidant property of free radicals, hence this research was aimed at extracting its oil from the morning and evening harvest of fresh and dried leaves using the hydrodistillation method, monitoring its phytochemical profile using Gas Chromatography-Mass Spectrometer (GC-MS) and evaluating their antioxidant activity using DPPH and Hydroxyl as source of radicals. Essential Oil was extracted from fresh leaves and dried leaves of Wedelia trilobata. Phytoconstituents revealed the presence of 14 – 24 compounds with the evening leaf oils possessing more quantitative and qualitative profile. Predominant constituents of the oils were alpha-pinene (21-32%) from the monoterpeniod origin and Germacrene-D (3.67-5.63%) from the sesquiterpenoids. Other abundant monoterpenoids included D-Limonene (13.00-15.64%), and alpha phellandrene (7.93-123.11%) while more abundant sesquiterpeniod included Caryophyllene (2.92-5.47%). All oils had potent antioxidant activity with the evening and dried leaf oil extracts having a higher antioxidant property than the oil from the fresh and Morning harvest, the evening oil extract had lower IC50 values than the oil from morning harvest and when compared to the ascorbic acid standard. Decreasing Concentration of the oil led to decrease in their antioxidant properties, hence diluting the oils can be avoided or requires knowing how much of the problem/free radicals are present. These oils from Wedelia trilobata can be used in food, drugs and cosmetics as better alternative sources of free radical scavengers with lower or no side effects as compared to synthetic antioxidants.
Audience Take Away:
- The audience will learn how times and seasons of harvest of a plant material affects the quality and quantity of phytochemicals obtained in a crude extract
- The research uses crude oil extracted to determine antioxidant activity; this can be expanded to isolation of pure individual components to ascertain which pure compound in the crude is/are responsible for the antioxidant activity. Hence more job opportunities are open for further research
- This research provides a solution to the problem of scavenging free radicals in the human body posed by synthetic antioxidants
- These essential oil are terpenes and can be used in teaching Natural Product Chemistry in research and tertiary institutions