α-GLUCOSIDASE INHIBITORY ACTIVITIES AND ANTIOXIDANT PROPERTIES OF DEPSIDONE FROM Garcinia parvifolia

Garcinia parvifolia, locally named “Aciu”, is commonly used by local people in East Kalimantan as a food additive and antibacterial, and for traditional therapies to treat high blood sugar levels, wounds, inflammation, and fever. In this study, in vitro, assays were carried out to evaluate extracts (n-hexane, dichloromethane, ethyl acetate, methanol residue) and an isolated compound from G. parvifolia fruits for their antidiabetic properties by inhibiting α-glucosidase and for their antioxidant activities by scavenging DPPH and ABTS^•+ free radicals. Bioassay-guided isolation of G. parvifolia fruits resulted in a secondary metabolite, namely garcinisidone A. Furthermore, Garcinisidone A showed stronger antidiabetic properties than extracts and positive controls (acarbose and quercetin) with IC₅₀ values of 6.61 μM. In addition, G. parvifolia fruits extract (dichloromethane) and garcinisidone A were found to have very strong antioxidant activities in comparison with the positive controls, namely ascorbic acid and quercetin. The results of this study confirmed the beneficial effects of G. parvifolia fruits as antidiabetic agents and free radical scavengers. This approach validates the ethnopharmacological use of G. parvifolia fruits for the treatment of diabetes and its complications caused by free radicals.