The temperature and extraction time of aqueous extracts of Vernonanthura patens (Kunth) H. Rob. (AEVP) leaves obtained by decoction were optimized for maximum recovery of DPPH radical scavenging activity, ABTS+ inhibition activity, total phenolic content (TPC) and total flavonoids content (TFC) using response surface methodology (RSM). A central composite design (CCD) of 13 experimental runs was applied and second order polynomial models were used to describe the responses of the assessed extraction parameters. The optimized conditions: 79.79 °C and 126.23 minutes were found using the composite desirability function. The scavenging activity of assessed extracts could be correlated mostly to the presence of malic acid, succinic acid, α-ketoglutaric acid, citric acid, m-hydroxybenzoic acid, caffeic acid, inositol, and β-amyrin detected by gas chromatography-mass spectrometry (GC-MS). These results have not been reported and support the potential application of AEVP as natural source of antioxidants.
Keywords: ABTS; DPPH; RSM; TEAC; catechin; gallic acid.