Polyphenols and antioxidant activities of selected traditional vegetables

Consumption of fruits and vegetables is associated with a lower risk of serious diseases such as cardiovascular disease and cancer. Fruits and vegetables are also widely reported as good sources of dietary antioxidants. Five selected Malaysian traditional vegetables, namely, Centella asiatica (L.) Urban (pegaga), Anacardium occidentale L. (gajus), Colubrina asiatica (peria pantai), Pluchea indica (beluntas) and Premna cordifolia (bebuas) from MARDI’s gene bank, Seberang Perai were screened for phenolic compounds and analysed for antioxidant activities using a Ferric Reducing Antioxidant Potential (FRAP) assay in two batches of sampling. Total phenolic content varied from 100–415 mg/kg gallic acid equivalent (GAE) in batch 1 and from 62–386 mg/kg GAE in batch 2. Anacardium occidentale had the highest total phenolic content followed by P. indica B and A, P. cordifolia, C. asiatica and the lowest was C. asiatica. Total antioxidant activity indicated that A. occidentale showed the highest activity which was probably due to these phenolics. Flavonol glycosides were predominant in most of the species, particularly A. occidentale with levels ranging 6.4–12.4 ± 0.3 mg/g fresh weight (fw). Chlorogenic acids were the main components identified and quantified in C. asiatica and P. indica. In this study, it was shown that the total phenolic content of plant extracts was positively correlated with total antioxidant capacity