The radical scavenging reaction of ascorbic acid with DPPH was,
essentially, instantaneous (Fig. 5). On the other hand, the radical
scavenging reaction of BHT with DPPH was rather slow and the
absorbance continued to decrease till a period of 90 min of observation
(Fig. 5). The reaction of DPPH with propyl gallate was also
quite fast but slower as compared to that with ascorbic acid
(Fig. 5). For the sake of uniformity, a time interval of 30 min was
taken for ascorbic acid, BHT and propyl gallate radical scavenging
capacity measurements. It is important to do a time course of radical
scavenging activity while using DPPH radical for the assay of
antioxidant activity