extracts of cotoneaster medicus, glycyrrhiza glabra, as endemic plants of iran, along with mixture of them were investigated for their antioxidant activities using 2, 2- diphenyl-1-picrylhidrazyl (dpph) reagent. uv-vis spectrophotometry method was used to evaluate the ability of cotoneaster and glycyrrhiza glabra antioxidant to scavenge dpph radical. the kinetic parameters such as rate constant...