Alpha-glucosidase inhibitory and antioxidant activity of solvent extracts and fractions of typha domingensis (Typhaceae) fruit

Abstract

Purpose: To identify a solvent fraction with potent antiglucosidase and antioxidant activities from the fruit of Typha domingensis. Methods: Extracts were prepared using hexane, chloroform, ethyl acetate, acetone (AE), methanol, and water. Antiglucosidase and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities of extracts were assessed. The most active extract was partitioned into chloroform, ethyl acetate, butanol (BF) and water, and the antiglucosidase and radical scavenging activities of the fractions were determined. Mode of inhibition of the strongest antiglucosidase fraction was investigated. Polyphenol, coumarin, proanthocyanidin (TPro), and hydroxycinnamic acid contents of the extracts and fractions were evaluated. Results: AE had the highest antiglucosidase (EC50 = 12.36 µg/mL) and radical scavenging (EC50 = 8.57 µg/mL) activities. Solvent-partitioning of AE resulted in BF, which showed markedly stronger antiglucosidase activity (EC50 = 4.27 µg/mL) than quercetin (EC50= 22.18 µg/mL). BF also had potent radical scavenging activity (EC50 = 7.20 µg/mL). BF was rich in TPro (735.65 mg/g) and was a competitive glucosidase inhibitor. TPro content correlated with antiglucosidase (R2 = 0.709) and DPPH scavenging activities (R2 = 0.838). Conclusion: TPro-rich BF of T. domingensis fruit is a highly potent glucosidase inhibitor and radical scavenger. The findings demonstrate a potential for the development of natural antihyperglycemic agents with antioxidant effect from T. domingensis fruit. © Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria