Antidiabetic Potential of Garcinia atroviridis Griff: In Vitro and In Vivo Evaluation of Glucose Metabolism and Enzyme Inhibition.

Diabetes mellitus (DM) is characterized by hyperglycemia, insulin resistance, and pancreatic β-cell failure, necessitating novel treatments. Garcinia atroviridis, rich in hydroxy citric acid (HCA), flavonoids, and polyphenols, shows potential against diabetes. In vitro and in vivo studies assessed its effects on glucose absorption, enzyme inhibition, and glycemic control in diabetic rats. The extract exhibited significant total phenolic (10.09 ± 0.24 mg GAE/g) and flavonoid (9.44 ± 0.11 mg QE/g) content. It demonstrated moderate direct antioxidant activity (DPPH IC₅₀ 15.14 ± 0.55 mg/mL) and inhibited α-glucosidase, α-amylase, and DPP-4 (IC₅₀ 35.04 ± 0.22 mg/mL, 22.21 ± 0.13 mg/mL). Crucially, in L6 myoblast cells, it enhanced glucose absorption (165.25% at 62.5 µg/mL) without cytotoxicity (IC₅₀ 3.12 ± 0.027 mg/mL). In diabetic rats, G. atroviridis (400 mg/kg) significantly reduced fasting blood glucose (69.33 mg/dL by day 21) and improved glucose tolerance. The findings suggest that the antidiabetic potential of G. atroviridis is likely driven by a multi-mechanistic synergy between its moderate direct antioxidant capacity, enzyme inhibition, and, most notably, its potent ability to enhance cellular glucose uptake at low concentrations. This positions G. atroviridis as a promising natural adjunct for diabetes treatment, warranting further research into its active compounds and clinical applications.