Novel zinc-chelating peptides from Moringa oleifera lam. leaves: Structural characteristics and hepatoprotective effects against ethanol-induced injury in AML-12 cells

This study identified novel zinc-chelating peptides derived from Moringa oleifera Lam. leaves, aiming to alleviate alcohol-induced oxidative injury in hepatic cells. The chelation mechanism was analyzed using spectroscopic techniques and computer simulations, while the antioxidant and hepatoprotective activities of the peptide‑zinc chelates were evaluated in an ethanol-injured AML-12 cell model. The <1 kDa ultrafiltration fraction of peptides displayed strong antioxidant activity. Two candidate peptides, HDYLTGGF and EYF, showed favorable docking interactions with Keap1 and CYP2E1. Structural analyses revealed that Zn 2+ bound to carboxyl/carbonyl sites, forming stable complexes with distinct dynamics: HDYLTGGF-Zn achieved dynamic stability after rearrangement, while EYF-Zn formed a compact, rigid structure rapidly. In ethanol-injured AML-12 cells, both chelates (50 μg/mL) increased intracellular labile Zn 2+ fluorescence, improved cell viability, reduced ROS and MDA levels, and restored SOD and CAT activities and GSH content. Under the equal-mass dosing condition, the chelate groups generally showed greater protection than the corresponding free peptides. These findings support the further development of MOLL-derived peptide–Zn complexes with hepatoprotective potential.