A study on antioxidant nature of petai (Parkia speciosa)

Abstract

The antioxidant activities of aqueous ethanolic extracts of petai seeds and pods were studied. Antioxidant activities were found using methods such as ABTS, DPPH and FRAP assay. They were found to show good scavenging activities with both ABTS+ and DPPH radical assays. It was noticed that pods of petai were more effective radical scavengers that petai seeds. The difference between them was found to be around 6 times. The reducing powers of them were also found to be good. Pods were found to have more reducing power than seeds and the difference between the reducing powers of the seeds and pods was around 19 times. The phenolic contents determined using Folin-coicalteu assay was high. The correlation between the antioxidant activities and the phenolic contents for the seeds and pods were found to be approximately 0.7. In the seeds there is a low correlation of total thiol content against the antioxidant activity. Vitamin C, an important antioxidant was determined in the seeds using HPLC and it was found to contribute around 8 % of the total antioxidant capacity, but this was absent in the pods. Many antioxidant compounds were found in the seeds and pods based on the reaction between radical solutions ABTS+ or DPPH with their extracts using HPLC. The LC-MS characteristics of around 15 compounds from the seed sand pod extracts were analysed.