BIOLOGICAL ACTIVITY OF METHANOL EXTRACT OF Elaeocarpus mastersii KING: ANTIOXIDANT, ANTIBACTERIAL, AND α-GLUCOSIDASE INHIBITOR

Plants are one of the natural resources that have great biological activity and have long been used in traditional medicine. In this research, methanol extracts of root, stem bark, and leaf of Elaeocarpus mastersii King were tested to determine phenolic and flavonoid content and evaluate their biological activities as the antioxidant, antibacterial, and antidiabetic using the method of DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, disc diffusion against Staphylococcus epidermidis (S. epidermidis), Staphylococcus aureus (S. aureus), Salmonella typhosa (S. typhosa), and Escherichia coli (E. coli), and inhibition of α-glucosidase enzyme, respectively. All parts showed high phenolic content and antioxidant activity wherein the leaf extract was found to be the highest value (340.36 ± 2.09 mg GAE/g DW and IC50 1.86 ± 0.00 µg/mL) followed by the stem bark (331.53 ± 6.96 mg GAE/g DW and IC50 2.43 ± 0.01 µg/mL) and the root (216.27 ± 3.19 mg GAE/g DW and IC50 3.37 ± 0.20 µg/mL), respectively. In contrast, their flavonoid values were very low. The stem bark exhibited the highest antibacterial activity against all of the tested bacteria. The activity of α-glucosidase inhibition revealed that the stem bark had the highest activity among all parts with the IC50 of 14.56 ± 1.20 µg/mL. This study demonstrates that Elaeocarpus mastersii King has a great biological activity as the antioxidant, antibacterial, and α-glucosidase inhibitor.