NGHIÊN CỨU TÁC DỤNG CHỐNG OXY HÓA VÀ TÁC ĐỘNG ỨC CHẾ α-GLUCOSIDASE IN VITRO CỦA CAO KHÔ QUẢ KHỔ QUA (Momordica charantia L.)

Abstract

Background: Inhibition of the enzyme α-glucosidase reduces the absorption of glucose in the blood after meals, contributing to the treatment of diabetes mellitus (DM). Thanks to the presence of components: Polyphenols, charantin, peptides, flavonoids, bitter fruit has a lot of potential in the prevention and treatment of oxidative stress diseases of the body, diabetes. Objectives: This study evaluates the antioxidant effects and investigates the α-glucosidase inhibitory effects in vitro of dry extract from bitter fruit. Materials and methods: Bitter fruit is dried, crushed, extracted by ultrasonic-assisted aqueous solvent. The extract is concentrated at 70⁰C and mixed with mannitol to make the finished product. Evaluation of antioxidant effects on the dry extract by free radical scavenging model by DPPH and FRAP methods. The α-glucosidase inhibitory effect of the extract was investigated by the pNPG substrate cleavage reaction of the enzyme α-glucosidase. Results: The dry extract from bitter fruit has an antioxidant effect through the ability to reduce DPPH free radicals with the IC₅₀ value of 78.70±1.80µg/mL, the IC₅₀ of the trolox being 0.97±0.02µg/mL. In the antioxidant activity test based on the FRAP model, the IC₅₀ of the dry extract was 341.76±0.88µg/mL, the IC₅₀ of the trolox was 4.35±0.01µg/mL. The dry extract from bitter fruit has α-glucosidase inhibitory effect with an IC₅₀ value of 460.20±0.24µg/mL, compared with IC₅₀ of acarbose is 9.24±0.14µg/mL. Conclusion: The study showed that bitter fruit has antioxidant activity and inhibits α-glucosidase, contributing to the direction of research and application of the extract.