In Vitro Glucose Uptake, α-Amylase, Antioxidant and Cytotoxic Evaluation of Dalbergiella Welwitschii as a Potential Glucose-Lowering Agent for Type 2 Diabetes

Abstract

Hyperglycemia is a major complication of type 2 diabetes. Medicinal plants could mitigate this complication due to their bioactive phytochemicals. Dalbergiella welwitschii is a plant used traditionally to manage hyperglycemia in Nigeria. This study explores the glucose-lowering potential of different parts of Dalbergiella welwitschii through in vitro glucose uptake and α-amylase inhibitory assays alongside antioxidant and phytochemical screening. The glucose uptake activity was evaluated using yeast cells (Saccharomyces cerevisiae) at glucose concentrations of 25, 10 and 5 mM, and extract concentrations of 1000, 500 and 250 µg/mL, respectively. α-Amylase inhibitory activity was determined using the 3,5-dinitosalicyclic acid (DNSA) method. Antioxidant activity was assessed using the DPPH radical scavenging assay and cytotoxicity was evaluated using the brine shrimp lethality assay. Stem extract of Dalbergiella welwitschii exhibited percentage glucose uptake of 92.20 ± 0.16, 96.70 ± 0.00, 85.40 ± 0.17 comparable to the standard Glimepiride-metformin-HCl (92.23 ± 0.06, 91.30 ± 0.10, 88.47 ± 0.42) at 10 mM glucose concentration. The leaf, stem and root had moderate α-amylase inhibitory activity (289.8 ± 0.03, 150.6 ± 0.03, 263.1 ± 0.03 µg/mL) compared with acarbose (33.2 ± 0.00 µg/mL). Phytochemical screening revealed the presence of alkaloids, flavonoids and phenols across all plant parts with higher concentrations in the leaves. The stem extract (0.403 µg/mL) exhibited strong antioxidant activity comparable to ascorbic acid (0.474 µg/mL) and butylated hydroxyanisole (0.315 µg/mL). Brine shrimp lethality assay indicated relatively low cytotoxicity for the extracts compared with the standard cyclophosphamide. These findings indicate that Dalbergiella welwitschii possesses promising glucose-lowering properties through a mechanism involving enhanced glucose utilization, moderate carbohydrate digestion and antioxidant activity supporting its potential for further pharmacological investigation.