Kigelia africana fruit fractions inhibit in vitro alpha-glucosidase activity: a potential natural alpha-glucosidase inhibitor

• Published in: BMC complementary and alternative medicine Vol. 24; no. 1; pp. 230 - 13
• Main Authors: Muyenga, Tumelo Akapelwa, Bamitale, Samuel K Dominion, Kibuule, Dan, Sithole, Simbarashe, Mukanganyama, Stanley, Rudolph, Carlen, Venables, Luanne, Hattingh, Anna C, van de Venter, Maryna, Ezeala, Christian Chinyere
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 12.06.2024; BioMed Central; BMC
• Subjects: Acetates; Acetic acid; Alpha-amylase inhibition; alpha-Amylases - antagonists & inhibitors; Alpha-glucosidase inhibition; alpha-Glucosidases; Amylases; Analysis; Bioassays; Biological activity; Cyclopentane; Diabetes; Diabetes mellitus; Diabetes therapy; Drugs; Enzymes; Esters; Ethyl acetate; Fractionation; Fruit - chemistry; Fruits; Gas chromatography; Gas Chromatography- mass spectrometry; Glucosidase; Glycoside Hydrolase Inhibitors - pharmacology; Humans; Hypoglycemic agents; Inhibitors; Iodine; Kigelia africana; Kigelia africana fruit fractions; Low income areas; Mass spectrometry; Mass spectroscopy; Metformin; Oxazolidine; Phytochemicals; Phytochemicals - chemistry; Phytochemicals - pharmacology; Phytochemistry; Plant Extracts - chemistry; Plant Extracts - pharmacology; Potassium; α-Amylase; α-Glucosidase; Zambia; Alpha-amylase inhibition; Alpha-glucosidase inhibition; Diabetes; Phytochemistry; Kigelia africana fruit fractions; Gas Chromatography- mass spectrometry
• ISSN: 2662-7671; 2662-7671; 1472-6882
• DOI: 10.1186/s12906-024-04510-5

Diabetes affects 75% of people in low-income countries, where conventional drugs like metformin are available, but newer drugs like alpha-glucosidase inhibitors are not accessible to most Southern African patients. To evaluate the α-glucosidase and α-amylase inhibitory activities of fractionated aqueous extracts of Kigelia africana fruit (KAFE) and their phytochemical fingerprints using gas chromatography-mass spectrometry (GC-MS). We studied K. africana fruit fractions' inhibitory effects on alpha-glucosidase and alpha-amylase using bioassay-guided fractionation, and analyzed their phytochemical profiles with GC-MS. Both the aqueous extract and ethyl acetate fraction of the aqueous extract exhibited a low dose-dependent inhibition of alpha-amylase activity (p < 0.0001). At a concentration of 500 μg/mL, the aqueous extract caused an alpha-glucosidase inhibition of 64.10 ± 2.7%, with an estimated IC50 of 193.7 μg/mL, while the ethyl acetate fraction had an inhibition of 89.82 ± 0.8% and an estimated IC50 of 10.41 μg/mL. The subfraction G, which had the highest alpha-glucosidase inhibitory activity at 85.10 ± 0.7%, had significantly lower activity than the ethyl acetate fraction. The most bioactive fraction was found to contain 11"(2-cyclopenten-1-yl) undecanoic acid, ( +)- and cyclopentane undecanoic acid as well as the indole alkaloids Akuammilan-17-ol-10-methoxy, N-nitroso-2-methyl-oxazolidine and epoxide Oxirane2.2″ -(1.4-butanediyl) bis-. The K. africana fruit fraction demonstrated significant alpha-glucosidase inhibitory activity, while its alpha-amylase inhibitory activity was limited. This study suggests a potential natural alpha-glucosidase inhibitor and phytocompounds that could serve as leads for developing antidiabetic agents.