The inhibition mechanism and binding properties of four phenolic acids (ferulic acid (FA), p-coumaric acid (CA), gallic acid (GA), and protocatechuic acid (PA)) on xanthine oxidase (XOD) were investigated. All four phenolic acids acted via a mixed inhibition pattern, mainly influencing the hydrophobic regions and secondary conformation of XOD through hydrophobic bonding and hydrophobic association. Molecular dynamics simulations exhibited that the complexes of XOD with FA and CA revealed smaller radii of gyration (Rg) and solvent-accessible surface areas (SASA), along with lower variability in root-mean-square deviation (RMSD) and root-mean-square fluctuation (RMSF), collectively indicating greater structural stability. FA, CA, and PA significantly reduced uric acid (UA) concentration in the 25–100 μM range. Although GA only reduced UA levels in cell models at 25 μM, this effect was likely due to its larger polar surface area, which limits cellular uptake. Absorption, distribution, metabolism, excretion, and toxicity (ADMET) evaluation suggested that these phenolic acids have potential for development.

The objective of this study was to develop an efficient method for decolorizing and deodorizing Asian swamp eel (ASE) hydrolysate. At an activated carbon (AC) dosage of 0.5 % and pH 4.0, insoluble peptides from trichloroacetic acid (TCA), which have poor antioxidant activity, were effectively removed. Meanwhile, other nitrogenous fractions with better antioxidant activity were retained, achieving a decolorization rate of 74.02 ± 0.38 %. Orthogonal partial least squares discriminant analysis (OPLS-DA) successfully distinguished the solid phase microextraction gas chromatograph-mass spectrometery (SPME-GC–MS) results of samples treated with different deodorization methods (ASE stock hydrolysate, AC treatment, AC + complex bacteria, AC + yeast, and AC + cyclodextrin). A total of 22 differential volatile compounds with variable importance projection (VIP) values greater than 1 were identified. The combination of AC treatment and cyclodextrin encapsulation effectively removed undesirable odors, enhancing the sensory quality and market competitiveness of the final product.

Fourteen novel antioxidant peptides were screened from the enzymatic hydrolysates of Asian swamp eel bone (ASEB) through an in silico analysis. Their ABTS and ORAC radical scavenging capacities were 1.70–4.29-fold and 2.79–5.90-fold higher than those of Trolox, respectively. Additionally, two novel peptide sequences (NVGW and WALN) were identified. Quantum chemical calculations combined with active–-site methylation experiments demonstrated that hydrogen atoms on tryptophan’s indole nitrogen, tyrosine’s phenolic hydroxyl, and arginine’s guanidinium group play crucial roles in enhancing ABTS and ORAC activities. Molecular docking further showed stable binding of ASEB peptides to myeloperoxidase (MPO) through hydrogen bonds and electrostatic interactions. Further studies indicated that ASEB alleviated oxidative stress in zebrafish by effectively reducing ROS accumulation, restoring redox homeostasis, and modulating the expression of Keap1–Nrf2 pathway-related antioxidant genes. These results enhance our understanding of the antioxidant properties of ASEB-derived peptides and support the high-value utilization of animal byproducts.