Antioxidant activity and total phenolic content in aqueous extracts of selected traditional Malay salads (Ulam)

The total phenolic contents (TPC) and antioxidant activities of five popular Malay raw salads or Ulam were investigated using DPPH radical scavenging and reducing ferric ion antioxidant power (FRAP) assays. The Ulam studied were the leaves of Cosmos caudatus (Ulam Raja), Oenanthe javanica (Selom), Murraya koenigii (Curry Leaf), Centella asiatica (Pegaga) and the seeds of Parkia speciosa (Petai). Ranking order of TPC (mg gallic acid equivalent per gram of plant on dry basis), TEACDPPH (μmol Trolox equivalent per gram of plant on dry basis) and TEACFRAP (μmol Trolox equivalent per gram of plant on dry basis) values were: Curry Leaf (33.18), Selom (31.8), Ulam Raja (31.3) > Pegaga (11.16) > Petai (6.45); Ulam Raja (212.8) > Selom (185.9) > Curry Leaf (82.1), Petai (67.62) > Pegaga (32.4); Selom (199.96) > Ulam Raja (183.11) > Curry Leaf (108.34) > Pegaga (65.99) > Petai (44.67), respectively. No significant correlation (p>0.05) was observed between antioxidant activities and TPC which could be due to steric hindrance or presence of other reducing agents. Interestingly, Selom showed antioxidant activities that are comparable to Ulam Raja.