Radical scavenging activity of A. santolina extract was measured according to the method of Blois (1958). Briefly, 1 ml of the crude extract at variable concentrations (25–400 μg/ml in ethanol) was added to 1 ml of a DPPH (1,1-diphenyl 2-picrylhydrazyl) solution (0.2 mM in ethanol) as the free radical source and kept for 30 min at room temperature. The decrease in the solution absorbance, due to proton donating activity by ASE component(s), was measured at 517 nm. l-Ascorbic acid was used as the positive control. The DPPH radical scavenging activity was calculated using the following formula: