Structural characteristics and physicochemical properties of Chinese yam protein extract with ameliorative effects on erectile dysfunction in diabetic rats

Chinese yam ( Dioscorea polystachya ) is an edible plant in China, known for its nutritional properties. In this study, Chinese yam protein extract (CYCSE) was extracted using cold-soaking extraction, and systematically evaluated for its composition, structural characteristics, physicochemical properties, and potential in protecting male reproductive function. Liquid chromatography-tandem mass spectrometry identified 22 proteins in CYCSE, with two dioscorin isoforms showing the highest peptide coverage (76–78%). The extract comprised proteins primarily below 90 kDa, rich in glutamate, aspartate, and arginine residues. Structurally, CYCSE exhibited characteristic protein ultraviolet and infrared absorption peaks, a high β-sheet content, a stable tertiary conformation, and high thermal stability (denaturation temperature 86.7 °C). Physicochemical properties showed that CYCSE has high solubility, water- and oil-holding capacity, emulsifying activity, and foaming stability. In vivo studies demonstrated that CYCSE significantly ameliorated glycolipid metabolic disorders, enhanced erectile function, and repaired cavernous damage in diabetic rats with erectile dysfunction. Mechanistically, CYCSE enhanced the NO/cGMP signaling pathway by activating the PI3K/Akt/eNOS axis in penile tissue. It also suppressed oxidative stress and inflammation by inhibiting the TXNIP/NLRP3 signaling pathway. These findings highlight the potential of CYCSE as a functional food ingredient for improving male reproductive health. • CYCSE is a protein extract derived from Dioscorea polystachya . • CYCSE exhibits stable protein structure and excellent food-functional properties. • CYCSE effectively restores erectile function in DMED rats. • CYCSE activates the PI3K/Akt/eNOS pathway to enhance NO/cGMP signaling. • CYCSE attenuates cavernous oxidative stress by suppressing the TXNIP/NLRP3 pathway.