Evaluation of Antioxidant and Enzyme Inhibition Properties of Siran Propolis: Correlations With Phenolic Content Determined by LC-MS/MS

Abstract

This study evaluates the antioxidant activity, enzyme inhibition potential, and phenolic composition of ethanolic Siran propolis extract. Antioxidant capacity was measured using reducing power (CUPRAC, FRAP, and Fe3+-reducing) and radical scavenging (DPPH·, ABTS·+, and DMPD·+) assays. The extract showed strong reducing ability, surpassing standard antioxidants in CUPRAC and FRAP assays, correlating with high ferulic acid (40.40 mg/g) and p-coumaric acid (88.60 mg/g) levels identified by LC-MS/MS. While it demonstrated notable DPPH· scavenging (IC50: 30.14 μg/mL), ABTS·+ activity was weaker (IC50: 272.44 μg/mL). Enzyme inhibition assays indicated effective inhibition of α-glycosidase, AChE (IC50: 2.15 μg/mL), hCA I, and hCA II. Notably, AChE inhibition was stronger than the standard tacrine inhibitor (IC50: 8.82 μg/mL), suggesting neuroprotective potential. The observed bioactivities are attributed to synergistic effects of phenolic acids and flavonoids, including quercetin, luteolin, taxifolin, and resveratrol. These findings highlight Siran propolis as a promising natural antioxidant and enzyme inhibitor source with potential therapeutic applications and food formulations.