Inhibitory Effect of Phenolic Extracts of Four Algerian Atlas Saharan Plants on α-Glucosidase Activity

Background: Diabetes mellitus is the most common disease in the world. One of the approaches therapy used to treat diabetes is inhibition of α -glucosidase activity by natural inhibitors from the plant. Objective: Our work comes to highlight, in vitro, the effect of phenolic extracts of some Algerian Saharan Atlas medicinal plants on the activity of α-glucosidase. Methods: The ethyl acetate extracts were prepared from hydro-methanolic (80:20) extracts of studied plants. The Folin-Ciocalteu method was used to determine the total phenolic content of the extracts. The α-glucosidase activity was determined by a microplate spectrophotometer at 405 nm using paranitrophenol α-D-glucopyranose as substrate. Results: Among the plants tested Arthrophytum scoparium, Helianthemum lippii, Equisetum arvense and Cistus villosus exhibited a strong α-glucosidase inhibitory activity. According to IC50 values, Arthrophytum scoparium exerted the highest inhibitory activity against α-glucosidase (IC50= 5.02 μM) while a weak inhibitory activity was observed with Equisetum arvense (IC50 =21.88 μM). The kinetic study revealed a noncompetitive type inhibition for Arthrophytum scoparium (KI = 4.16 μM) and Helianthemum lippii (KI = 1.46 μM) extracts whereas a full mixed type inhibition (KI = 18.17 μM; KIS = 3.98 μM) and competitive type inhibition (KI = 25 μM) were observed for Cistus villosus and Equisetum arvense, respectively. Conclusion: The results suggest that these plants represent a potential source to develop new antidiabetic drugs for controlling postprandial blood sugar.