Antioxidant Potential of Most Commonly Used Vegetable - Onion (Allium cepa L.)

Abstract

Antioxidants are known to play a vital role in inhibiting and scavenging free radicals, thus, provide immunity to human body against various infections and chronic diseases. Nowadays the modern research is moving towards plant based “Natural antioxidants” due to their safety, easy availability and better curative value. So the main reason of the present study was to assess the in-vitro antioxidant activity of the extracts of Allium cepa which is a very commonly used food worldwide. Aim: Estimation of in-vitro antioxidant activity of the Allium cepa extract. Study Design: Red onions were purchased from the market, washed in water to remove the dust and then dried for 20 days. The methanol and aqueous extracts of the bulb were prepared and investigated for their antioxidant activity. Methodology: The methanol and aqueous extracts of the bulb were prepared and investigated for their antioxidant activity by using FeCl3, DPPH, Superoxide scavenging and FRAP methods. The total phenolic content was determined by Folin-Ciocalteu reagent. Results: The total phenolic content showed a higher value (47 mg/100 ml) in the aqueous extract compared to (41 mg/100 ml) in the methanol extract. The antioxidant activity of aqueous extract by using FeCl3, DPPH, Superoxide scavenging and FRAP methods were found to be 13.1%, 23%, 33%, 21.7% and that of methanol extract were 17.5%, 35.5%, 37.8%, 38.7% respectively. Conclusion: From the above study it has been concluded that, both extracts showed an important antioxidant activity. However the methanol extract proved to have higher antioxidant activity. It was further observed that the phenolic content was higher in the aqueous extract of Allium cepa. Further study will be conducted to isolate the active components responsible for the activity.