From Literature-Guided Plant Selection to Molecular Insights: Characterizing α-Amylase Inhibitors from Selected Cameroonian Medicinal Plants
William Dakam, Francois Eya'ane Meva, Marxym Dilan Fossi, Judith Caroline Ngo Nyobe, Jean Baptiste Hzounda Fokou, Bertin Sone Enone, Jean Emmanuel Mbosso Teinkela, Jules Clement Assob NguediaBackground:
Safe and effective natural α-amylase inhibitors remain relevant for controlling postprandial hyperglycemia in Type 2 Diabetes Mellitus (T2DM). Several Cameroonian medicinal plants have shown promising inhibitory activity, but the compounds underlying these effects remain insufficiently characterized.
Methods:
In this study, a literature-guided plant selection strategy was used to identify candidate species and contextualize the experimental work. Crude extracts from Annona muricata, Monodora myristica, Garcinia kola, and Terminalia superba were evaluated in vitro, and the most active extract was subjected to bio-guided fractionation. Metabolite profiling of active fractions was performed using LC-MS coupled with multivariate analysis. Molecular docking and MMGBSA binding free-energy calculations were employed to explore potential interactions between identified compounds and human pancreatic α-amylase.
results:
Terminalia superba bark extract exhibited the highest inhibition (83.75%), comparable to acarbose. Metabolite profiling of active fractions identified 11 compounds among which thermopsoside, catechin 4-O-glucoside, and luteonyl 7-O-glucoside are suggested as major bioactive compounds. Molecular docking revealed strong interactions of these compounds with catalytic residues Asp197, Glu233, and His299 in human pancreatic α-amylase.
Results:
Terminalia superba bark extract exhibited the highest inhibition (83.75%), comparable to acarbose. Metabolite profiling of active fractions putatively identified 11 compounds, including luteolin- 7-O-glucoside, quercetin, and arjunolic acid derivatives, as candidate bioactive compounds. Molecular docking revealed strong interactions of these compounds with catalytic residues Asp197, Glu233, and Asp300/His299 in human pancreatic α-amylase.
Discussion:
The results support T. superba as a promising source of α-amylase inhibitory constituents. The convergence of bioassay-guided fractionation, LC-MS profiling, and in silico analysis suggests that the observed activity is likely mediated by several complementary phytochemicals rather than by a single compound.
Conclusion:
This integrative experimental study provides mechanistic insight into the α-amylase inhibitory potential of selected Cameroonian medicinal plants and supports further isolation, kinetic validation, toxicity testing, and in vivo evaluation of the most promising compounds before therapeutic relevance can be established.