Comparative Analysis of Total Phenolic Content and Anti-Oxidant Activity of Vegetables

Abstract

The antioxidant activity and total phenolic content of alcoholic extracts from 14 vegetables were evaluated by using a model system consisting of β-carotene, linoleic acid and Folin-Ciocalteau method. The total phenolics of the extracts was determined spectrophotometrically according to the Folin-Ciocalteau procedure and ranged from 28-74 mg /100 gm on a fresh weight basis. Broccoli, mint, holy basil, curry leaves, beetroot and black carrot have high antioxidant activity. The antioxidant activity expressed as percent inhibition of oxidation ranged from a high of 79% in broccoli extracts to a low of 57% in spring onion. Other vegetables found to have high antioxidant activity (>72%) were broccoli, mint, holy basil, curry leaves, beetroot and black carrot. Antioxidant activity correlated linearly significantly and positively with total phenolics. The results indicate that vegetables containing high phenolics may provide a source of dietary antioxidants. Using Thin Layer Chromatography (TLC), 14 vegetables were screened for the presence of total phenolics. Further, High Performance Liquid Chromatography (HPLC) was carried out for broccoli that showed the highest antioxidant activity but low phenolic content.