Study on UV-Vis absorption spectrometric investigation of the gallic acid against DPPH free radicals

The UV-Vis absorption spectrum of gallic acid which is natural antioxidant and DPPH free radicals was investigated, and the determination wavelength (517nm) and the time (30min) for the reaction of gallic acid with DPPH free radicals were optimized. Furthermore, the DPPH free radical scavenging activity of gallic acid was evaluated. And the half inhibitory concentration (IC50) of gallic acid against DPPH was 0.92μg/mL, which was significantly lower than that of standard antioxidant rutin (3.99μg/mL) . The result suggests that gallic acid had high DPPH free radical scavenging activity.