Characterisation of secondary metabolites from 50% ethanol extract of ebony leaves (Diospyros celebica Bakh.) and in vitro activity analysis of antioxidant and α-glucosidase inhibitor.

Diospyros celebica Bakh leaves are traditionally used to lower blood glucose levels. This study aimed to evaluate the antioxidant and α-glucosidase inhibition activity of extracts, fractions, and isolated compound from D. celebica leaves extracted using 50% ethanol. The extract and fractions were analysed by TPC, TFC, antioxidant activity, α-Glucosidase inhibitor, and LC-HRMS. Results indicate that the ethyl acetate fraction exhibited the most potent antioxidant (DPPH IC50 = 9.07 ± 0.05 μg/mL) and α-glucosidase inhibition (IC50 = 4.98 ± 1.18 μg/mL). The LC-HRMS analysis of the extract and fractions showed that D. celebica 50% ethanol extract is predominantly composed of phenolic and flavonoid compounds. Compound isolation from the ethyl acetate fraction yielded epiafzelechin-3-O-gallate, which exhibited a DPPH IC50 value of 10.26 ± 0.03 μg/mL and an α-glucosidase IC50 value of 76.85 ± 5.08 μg/mL. These findings indicate that D. celebica 50% ethanol extract, fractions, and isolated compound showed antioxidant and antidiabetic potential.