Abstract: This study investigated the free radical scavenging capacity of sea buckthorn procyanidins (SBPC) and evaluated their antioxidant activity at the cellular level, and it also assessed the α-glucosidase inhibitory effect and mechanism of SBPC. The results indicated that SBPC exhibited stronger scavenging capacity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) cation radical, and Fe3+ reducing power than did VC within the concentration range of 0–40 μg/mL. At concentrations of 10 and 40 μg/mL, SBPC scavenged 98.18% and 87.08% of DPPH radical and ABTS cation radical, respectively. At the cellular level, 20 μg/mL of SBPC significantly reversed the decline in HepG2 cell viability caused by palmitic acid (P < 0.001), and various concentrations of SBPC significantly reduced cellular ROS levels (P < 0.001). Additionally, SBPC exerted antioxidant effects by inhibiting the production of lipid oxidation products such as malondialdehyde (MDA) and by regulating the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Furthermore, SBPC demonstrated a significant inhibitory effect on α-glucosidase in a reversible competitive manner, with a 50% inhibition concentration of 8.646 μg/mL. It was found that SBPC interacted with amino acid residues at one or more active sites in α-glucosidase, forming hydrogen bonds and hydrophobic interactions, thereby inhibiting α-glucosidase. This study confirmed that SBPC possessed significant antioxidant and α-glucosidase inhibitory activities, providing a theoretical basis for its potential development as a hypoglycemic ingredient of functional foods.

Key words: sea buckthorn procyanidins; antioxidant; α-glucosidase inhibitory activity