ANTIOXIDANT AND FREE RADICAL SCAVENGING ACTIVITY OF DIFFERENT EXTRACTS OF THREE VARIETIES OF CARISSA CARANDAS FRUITS AND INHIBITION OF DIGESTIVE ENZYMES RELEVANT TO TYPE 2 DIABETES MELLITUS

Carissa carandas is a well-known traditional medicinal plant with a wide range of pharmaceutical properties. In the present studies, three Carissa carandas fruit extract varieties were investigated for the activities relevant to type 2 diabetes mellitus, including inhibition of α-amylase and α-glucosidase. Different solvent extracts such as methanol, ethanol, and aqueous extracts of Carissa carandas fruits were evaluated to determine the level of biological activities such as antioxidant activity and free radical scavenging activity by in-vitro approaches. Sour green, sour pink and sweet varieties of Carissa Carandas fruits were used in this study. Free radical scavenging activity of fruit extracts was assessed using DPPH, H₂O₂, hydroxyl radical, nitric oxide radical, ferric ion, and total antioxidant capacity. Among the three different extracts from the three varieties, the ethanol extract of the sour green variety showed the strongest α- amylase, and α -glucosidase inhibition (IC₅₀ = 270.4±1.73 µg/ml and 127.96±0.91 µg/ml), mainly due to the higher antioxidant activity. These extracts were evaluated using various in-vitro assays such as hydroxyl radical scavenging activity, nitric oxide scavenging, hydrogen peroxide scavenging, DPPH, and ferrous ion chelating activity. Methanol, ethanol, and aqueous extracts from the three varieties protected the lipids and proteins from oxidative stress. The higher anti-diabetic activity and free radical scavenging activity of sour green fruit ethanol extract can be allocated to a high content of its phenolic compounds. The present study provided data showing the use of green sour fruit extract for therapeutic application.