Purification, structural characterization, antioxidative and hypoglycemic activities of the peptides from hemp seeds

Hemp seeds are a rich source of protein with potential health benefits, and the extraction and purification of bioactive peptides from these can make the development of novel functional food ingredients and therapeutic agents. Single-factor and response surface experiment were carried out with the yield of peptides as the main determination index to identify the optimal process conditions. The highest peptides yield, which was 66%, was achieved with the 2% enzyme addition, the temperature of 60 °C, and the duration of 4 h. Next, a component with enhanced activities, named HSP4-1, was prepared from the hydrolysate after ultrafiltration and Sephadex G-15 chromatography. HSP4-1 exhibited significant antioxidant activity, as evidenced by its scavenging effects on DPPH, hydroxyl radicals, and ABTS, with IC₅₀ values of 0.19, 0.14, and 0.52 mg·mL⁻¹, respectively. Additionally, it demonstrated α-glucosidase inhibitory activity, with an IC₅₀ of 0.17 mg·mL⁻¹. The sequences of the peptides were subsequently determined by high-performance liquid chromatography-mass spectrometry (HPLC–MS), as AGFLGVDEFR, AGLFNSR, and LAFDR, which are hypothesized to contribute to the bioactivities. The identified peptides have the potential to serve as raw materials for natural antioxidants and hypoglycemic drugs. This not only facilitates their application in the development of functional foods and pharmaceuticals but also offers valuable process parameters and theoretical support for the deep processing and high-value utilization of hemp seeds.