Evaluation of Antioxidant Activity of Vegetable Extracts and Determination of Some Active Compounds

Abstract

Prevention of autoxidation of emulsified linoleic acid was determined by the method to measure the rate of discoloration of beta-carotene coupled with the oxidation of linoleic acid. By the method, antioxidant activity of forty-three kinds of vegetable extracts were examined. The results were as follows. (1) Thirteen kinds of vegetable extracts, such as garland, ginger and asparagus, that contained in 100g of vegetable weight, showed the activities corresponded to more than 25mg of authentic antioxidant BHA (high activity group). And the activities another thirteen kinds of vegetable extracts from pumpkin, cucumber and turnip et al., each also contained in 100g of vegetable weight corresponded to less than 5mg of BHA (low activity group). The activities of another seventeen kinds of vegetables corresponded to the intermediate level of high activity group and low activity group. (2) The correlation of the content of polyphenol and antioxidant activity of the vegetables extracts was 0.7694. (3) The main antioxidants of asparagus, ginger and garland determined by MS spectrum method were rutin, gingerol and hexahydrocurcumin, and isochlorogenic acid and acyl substituted isochlorogenic acid, respectively.