The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay
was estimated according to the procedure described by CardadorMartinez
et al. (2002) with a slight modification. The essential oil of
H. coronarium was dissolved in EtOH at different concentrations.
Different dilutions of the oil (4 ml) were added to 1 ml of 0.5 Mm
DPPH (in EtOH), resulting in a final concentration of 0.1 mm DPPH.
The mixture was shaken vigorously and left for 30 min in the dark at
room temperature. The absorbance was measured at 517 nm. The
scavenging capacity was calculated as follow.
Scavenging capacity % = [1 − (Atest/Acontrol)] × 100