Fig. 5. Time course of scavenging of DPPH free radical by ascorbic acid, BHT and
propyl gallate. The reaction mixture (4.0 ml) in buffered methanol contained DPPH
(50 lM) alone or in the presence of ascorbic acid (11.5 lM), BHT (9.7 lM) or propyl
gallate (4.7 lM). The absorbance was measured at 517 nm.