A thermodynamic in vitro antioxidant study of vitamins B (niacin and niacin amide) and C (ascorbic acid) with DPPH through UV spectrophotometric and physicochemical methods

The figure shows an effect of temperature on the free radical scavenging activity of niacin, niacinamide and ascorbic acid where their structure-activity relationship in terms of antioxidant nature is found as AA > NCN > NMD at T = (298.15, 303.15 and 308.15) K