Antioxidant and α-glucosidase inhibitory activities of Syneilesis Palmata Maxim seed extracts

Abstract

Syneilesis palmata Maxim., a plant that grows across the Korean Peninsula, has been traditionally used as a wild, edible green and as a folk remedy. This study analyzed the antioxidant activity and alpha-glucosidase inhibitory activity of S. palmata seeds, which had not been previously studied. The extracts were prepared from seeds collected in Bonghwa, Gyeongsangbuk-do in 2018. The total phenolic content was found to be the highest in the MeOH extract at 11.23 mg GAE/g seeds, while the total flavonoid content was the highest in the MeOH extract at 3.69 mg QE/g seeds. The DPPH-radical scavenging activity showed the highest EC 50 in the MeOH extract at 67.0 μg/mL, while the ABTS-radical scavenging activity had the highest EC 50 in the MeOH extract at 24.7 μg/mL. The FRAP value was the highest in the MeOH extract at 1354.5 μM Fe(II)/g extract. The α-glucosidase inhibitory activity showed the highest IC 50 in the MeOH extract at 17.43 μg/ mL. Additionally, individual phenolic compounds were detected in the extract with high α-glucosidase inhibitory activity. Our results thus confirmed that the MeOH extract of S. palmata seeds is rich in phenolic compounds and exhibits antioxidant and αglucosidase inhibitory activities, which together suggest its potential application as an effective functional food and natural medicine.