Comparative Analysis of Antioxidant and Antidiabetic Potential of Vatica granulata Leaf and Branch Extracts

To date, the phytochemical profile and bioactivities of Vatica granulata remain completely unknown. Therefore, this study aims to provide the first evaluation of phytochemical profile, antioxidant capacity, and α-glucosidase inhibition of V. granulata leaf (VGLE) and branch (VGBE) extracts. Total phenolic (TPC) and total flavonoid (TFC) contents were quantified, and antioxidant activity was evaluated using DPPH, ABTS, and FRAP assays. Antidiabetic activity was determined using α-glucosidase inhibition assay to assess clinical relevance for Type 2 Diabetes management. All experiments were performed in independent triplicates (n = 3) and analyzed using independent t-test and One-way ANOVA. The result showed that VGBE possessed significantly higher TPC (164.89±9.07 mg GAE/g) and TFC (13.83±0.73 mg QE/g) compared to VGLE. Interestingly, this variance did not translate to statistically significant differences in bioactivity (p > 0.05), suggesting the presence of bioactive constituents in both parts. Both extracts demonstrated strong ABTS scavenging (IC50 < 12 µg/mL) but moderate activity against DPPH. Notably, both extracts exhibited strong α-glucosidase inhibition (IC50: 12.83-18.10 µg/mL) which was statistically comparable to standard drug acarbose (IC50: 14.55 µg/mL, p > 0.05). The inhibitory activity in crude extracts comparable to reference standard implies the presence of potent bioactive metabolites. These findings fill a critical gap in the chemotaxonomy of the family Dipterocarpaceae and establish V. granulata as a promising candidate species for natural antidiabetic agents.