Purification, characterization and anti-hyperuricemic mechanism of novel xanthine oxidase inhibitory peptides from tea (Camellia sinensis L.) protein

In this study, two novel xanthine oxidase inhibitory peptides, PDEAVAYG (820.3602 Da) and IAAGLQNTG (843.4450 Da), were purified and identified from tea protein hydrolysate, and their IC50 values were 0.09 mg/mL (109.71 mu M) and 0.24 mg/mL (284.55 mu M), respectively. During the gastrointestinal simulation digestion, PDEAVAYG was broken down into new peptides, while IAAGLQNTG exhibited some stability. Molecular docking results showed that hydrogen bonding, Ic-Ic stacking, and hydrophobic interactions exerted crucial effects on the interaction between peptides and xanthine oxidase. In the hyperuricemia cell model, compared to the model group, 1.0 mg/mL of PDEAVAYG and IAAGLQNTG decreased cellular uric acid levels by 40.80% and 33.33%, respectively. The RNA-seq experiments revealed that PDEAVAYG could alleviate hyperuricemia by regulating mRNA expression for pro-inflammatory factors, growth factors associated with cardiovascular disease, and uric acid efflux transporter proteins in cells. This study provides a new theoretical reference for the development of functional foods or nutritional supplements using peptides with anti-hyperuricemic activity.