Figure 3.

The ability of the aqueous extract from Aloe vera leaf or α-tocopherol and ascorbic acid, used as reference antioxidants to scavenge DPPH^• was estimated as a function of increasing extract (from 5 to 60 mg/ml) or α-tocopherol (from 0.031 to 0.5 mg/ml) and ascorbic acid (from 0.008 to 0.25 mg/ml) concentrations and by recording the decrease in absorbance at 517 nm. The results were expressed as a mean percent DPPH scavenging activity of the extract (from 6.4 ± 0.84 to 70.8 ± 0.27%), α-tocopherol (from 8.7 ± 1.06 to 88.3 ± 1.81%) and ascorbic acid (from 10.6 ± 1.74 to 96.01 ± 0.37%), derived from three separate assays. The extract (at 60 mg/ml) was significantly less effective (p < 0.05) than α-tocopherol (at 0.5 mg/ml) and ascorbic acid (at 0.25 mg/ml).