Comparison of Free Radical Scavenging Capacities of Methanol Extract of Two Mint Species by Fixed Point and Kinetic Methods

Mentha Longifolia (ML) and Mentha Puleguim (MP) are usually used as a flavor and medicinal plants in Saudi Arabia. The present study was carried out to compare the potential of methanol extract of fresh leaves of ML and MP as free radical (DPPH) scavenger by fixed point and kinetic methods. In a fixed point method, free radical scavenging capacity was expressed by effective concentration, EC50. However, in kinetic method, capacity expressed by rate constant value. Some other antioxidants parameters like total flavonoids content and total phenolic content were also estimated. Flavonoid content was obtained as catechin equivalent and total phenolic content as gallic acid equivalent. The obtained results indicate that methanol extract of MP possess a high concentration of flavonoids (6.55± 0.42 mg/100 ml) and of phenolic (3.72 ±0.29 mg/100 ml) compared to that of ML flavonoids (3.22± 0.43 mg/100 ml) and of phenolic (1.91 ±0.06 mg/100 ml)