Screening of traditional Lebanese medicinal plants as antioxidants and inhibitors of key enzymes linked to type 2 diabetes

This study aimed to investigate the inhibitory activity of key enzymes linked to type 2 diabetes (?-amylase and ?-glucosidase) and the antioxidant properties of non polar (n-hexane) extracts from Coffea arabica, Citrus lanatus, Cucumis melo, Cuminum cyminum, Cocos nucifera, Coriandrum sativum, Foeniculum vulgare, Nigella sativa, Rhus coriaria, Pimpinella anisum, Syzygium aromaticum and Sesamum indicum collected in Lebanon. Extracts were analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antioxidant activity was investigated by using different in vitro methods namely 2,2?-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), Ferric Reducing Ability Power (FRAP) and ?-carotene bleaching tests. C. melo showed the highest ?-glucosidase inhibitory activity with an IC50 value of 25.55??g/ml, followed by C. lanatus white seeds and S. indicum (IC50 of 34.41 and 38.78??g/ml, respectively). S. indicum exhibited also the highest protection of lipid peroxidation with IC50 values of 0.07 and 0.06?mg/ml after 30 and 60?min of incubation, respectively.