ABSTRACTAcanthospermum hispidum, Alchornea laxiflora, Calyptrochilum christyanum, Heliotropicum indicum, Holarrhena floribunda, Ipomoea asarifolia, Nauclea diderrichii, Piper guineense, and Tetracera scandens were extracted into methanol and screened for the availability of alpha-amylase inhibitors. Plant extracts’ toxicity was determined by brine shrimp lethality assay (BSLA). The most active plant, Nauclea diderichii, was fractionated into four solvent systems (n-hexane fractions, ethyl acetate, dichloromethane, and n-butanol) and tested. All the extracts showed varying degrees of alpha-amylase inhibitory activity. N. diderrichii with IC50 = 248.30 ± 0.27 µg.mL–1 had the highest inhibitory activity, while its butanol fraction with IC50 = 137.8 µg.mL–1 had activity comparable to the standard α-amylase inhibitor acarbose (IC50 = 177.50 ± 0.42 µg.mL–1). LC50 values for BSLA ranged from 11.35 to 1,127.50 µg.mL–1, with T. scandens being the most toxic with 11.35 µg.mL–1 and N. diderrichii the least toxic with 1,127.50 µg.mL–1.