Fig. 7.

Antioxidant activity studies of the stem bark extract of Nerium oleander: (I) UV–visible spectra of (a) DPPH, (b–e) DPPH + with ethanol extract of stem bark 50, 100, 150 and 200 μg/mL. Inset: photographs of the vials containing the solutions of (a) DPPH, (b–d) DPPH + with ethanol extract of stem bark 50, 100 and 150 μg/mL. II Reaction scheme showing quenching of DPPH radical by the antioxidant (A–H); (III) plot of % DPPH radical scavenging by the ethanol extract stem bark