Evaluation of Antioxidant Potentials and α -Amylase Inhibition of Different Fractions of Labiatae Plants Extracts: As a Model of Antidiabetic Compounds Properties.

In an attempt to identify herbal drugs which may become useful in the prevention of diabetes, antioxidant potentials and α -amylase inhibition by the ethanol extracts of two plants belonging to Lamiaceae family, Otostegia persica and Zataria multiflora , and their different fractions were studied. Also, inhibition of α -amylase by Salvia mirzayanii and its fractions was evaluated. All of the samples exhibited antioxidant activities, among which ethyl acetate fraction of Zataria multiflora (17.21 ± 0.17 mg GAE/g) was found to contain the highest amounts of phenols and the ethyl acetate fraction of Zataria multiflora (218 ± 2.76 mg QUE/g) had the most values of flavonoids. Ethyl acetate fraction of Zataria multiflora (IC50 = 3.05 ± 0.51  μ g/ml) was shown to have the most reducing power and the ethyl acetate fraction of Zataria multiflora (IC50 = 32.17 ± 1.82  μ g/ml) exhibited the highest DPPH radical scavenging. The ethyl acetate fraction of Otostegia persica (99.39 ± 0.94%) showed the highest α -amylase inhibitory activity which was similar to acarbose used as a standard. Mode of α -amylase inhibition of the most samples was uncompetitive except for ZMC , OPP , OPC , and SMP which presented competitive inhibition. The present findings showed that studied samples may have some compounds with antioxidant and antidiabetic effects.