Antioxidant capacities of vegetables consumed in north east India assessed by three different in vitro assays

Abstract

The antioxidant capacity of the vegetables consumed in North East India was estimated by three different in vitro methods. A total of 22 (twenty two) vegetables were evaluated using the extracts for their ability to scavenge the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals, ability to reduce ferric ions determined by Ferric Reducing Antioxidant Potential (FRAP) assay and Total phenolic content. The antioxidant capacity was expressed as mg Trolox equivalents for DPPH radicals scavenging and FRAP assay while the total phenolic content was expressed as mg Gallic acid equivalent (GAE) per 100 gm of edible portion of the vegetables. The antioxidant capacity of the vegetables estimated by the three methods does not vary markedly though the values of total phenolic content was slightly higher compared to that of the other two methods. The highest antioxidant capacity was observed in stink bean and least in cucumber. Based on the antioxidant capacity, the vegetables were grouped into four categories i.e. extremely high, high, medium and low. Stink bean (Parkia speciosa) showed an extremely high antioxidant activity in all the three methods. The vegetables with high antioxidant capacity includes bean leaves, brinjal, mustard leaves, potato and pea while pumpkin leaves, radish, tomato, naga chilli, small chilli and hyacinth bean fall in medium okra, broccoli, banana flower, cabbage, turnip, common beans, cauliflower, carrot and cucumber in low category.