A bioactive protein from Dioscorea polystachya residue alleviates hydrocortisone-induced erectile dysfunction in rats via TXNIP/NLRP3 pathway inhibition.

The reuse of proteins from food industry by-products contributes to the circular economy and reduces ecological damage. This study isolated a protein named DP1 from residue of Dioscorea polystachya (Chinese yam) and investigated its structural characteristics and biological activities. DP1 is a homogeneous, monomeric protein with a molecular weight 11.751 kDa, containing 13 essential and nonessential amino acids. It exhibited an overall layered structure with a smooth surface, characteristic protein ultraviolet and infrared absorption peaks, stable secondary and tertiary structures, and excellent thermal stability (denaturation temperature 113 °C). While DP1 from fresh Chinese yam has been reported to protect against hydrocortisone (HCT)-induced testicular dysfunction, its efficacy when isolated from industrial processing residue remains unexplored. We hypothesize that it may be promising in managing erectile dysfunction. Results showed that DP1 increased penile erection rate in HCT-induced rats, reduced erection latency, increased NO and cGMP levels, and restored endothelial function both in vivo and in vitro. Mechanistically, DP1 targeted the inhibition of TXNIP shuttle to mitochondria, thereby reducing oxidative stress and suppressing NLRP3 inflammasome activation. Our study suggests that DP1 has potential as a supplement to protect male erectile function, providing new opportunities for the effective recovery and use of Chinese yam by-products.