Nauclea latifolia Sm. Leaf Extracts Extenuates Free Radicals, Inflammation, and Diabetes-Linked Enzymes

This study was carried out to assess the in vitro antioxidant, anti-inflammatory and antidiabetic effects of Nauclea latifolia (Sm.) leaf extracts. Ethanolic (NLE) and aqueous (NLA) extract of N. latifolia leaves were prepared and assessed for their anti-inflammatory activity, antioxidant potential, α-amylase and α-glucosidase inhibitory activities, and the mechanism of enzyme inhibition in vitro using standard established methods. From the results, phytochemicals such as flavonoids, phenolics, glycosides, and tannins were detected in both extracts of N. latifolia with NLE having a significantly (p < 0.05) higher phytochemical content. NLE displayed significantly (p < 0.05) better total antioxidant capacity, reducing power, 2,2-diphenyl-2-picrylhydrazyl, and hydrogen peroxide radical scavenging activities. For anti-inflammatory activities, 70.54 ± 2.45% albumin denaturation inhibition was observed for NLE while 68.05 ± 1.03% was recorded for NLA. Likewise, 16.07 ± 1.60 and 14.08 ± 1.76% were obtained against hypotonic solution and heat-induced erythrocyte haemolysis, respectively, for NLE while 20.59 ± 4.60 and 24.07 ± 1.60% were respective NLA values. NLE (IC(50): 4.20 ± 0.18 and 1.19 ± 0.11 mg/mL) and NLA (IC(50): 11.21 ± 0.35 and 2.64 ± 0.48 mg/mL) α-glucosidase and α-amylase inhibitory activities were dose-dependent with uncompetitive and competitive inhibition elicited, respectively, by the extracts. A significant positive association (p < 0.01 and 0.05) was identified between antioxidant activity and carbohydrate-metabolising enzyme inhibitory activity. The obtained result suggests N. latifolia leaf could serve as an alternative candidate for managing diabetes mellitus due to its antioxidant and anti-inflammatory association with diabetes-linked enzymes.