Unveiling the anti-diabetic effects of <i>Garcinia hombroniana</i> fruit pericarp and leaf<i>: in vitro</i> radical scavenging, alpha-glucosidase inhibition, pharmacokinetics, and <i>in silico</i> molecular docking of Q-TOF-LCMS identified compounds

<i>Garcinia hombroniana</i> is traditionally used to treat diabetes in Malaysia. However, scientific studies have yet to identify the phytoconstituents responsible for its blood glucose-lowering effects. This study aimed to evaluate the antioxidant and α-glucosidase inhibitory effects of <i>G. hombroniana</i> fruit pericarp and leaf dichloromethane (DCM) and ethanol (EtOH) extracts and identify the active principles. The extracts were analysed for their total phenolic and flavonoid contents (TPC, TFC), <i>in vitro</i> antioxidant activity <i>via</i> radical scavenging, and α-glucosidase inhibitory effect. Additionally, QTOF-LCMS analysis using negative and positive polarisation modes was conducted to identify potential α-glucosidase inhibitors. The identified compounds underwent comprehensive screening, including pharmacokinetics, drug-likeness rules, PASS analysis, and toxicity assessments. Their α-glucosidase inhibitory effect was further validated using a molecular docking approach. All extracts showed significant TPC and TFC values, as well as antioxidant effects. Notably, DCM fruit pericarp (4.11 ± 0.91 μg/mL), DCM leaf extract (1.49 ± 0.68 μg/mL), and ethanolic leaf extract (2.21 ± 0.50 μg/mL) exhibited potent α-glucosidase inhibitory effects, surpassing quercetin (5.11 ± 1.07 μg/mL) used as a standard. The QTOF-LCMS analysis identified 191 compounds, of which 19 were selected for <i>in silico</i> molecular docking. These compounds were confirmed as α-glucosidase inhibitors and suggest that <i>G. hombroniana</i> extracts may be used for managing postprandial glucose in diabetic patients.