Optimizing Fermentation of Morus nigra L. Residues with Schizophyllum commune to Enhance Anthocyanin Release and Anti-Inflammatory Activity via Pyroptosis Pathway Modulation

Morus nigra L. is rich in anthocyanins and other active ingredients, but its extraction residues pose a burden on the environment. In the present study, Morus nigra L. extraction residue resource utilization was achieved through liquid fermentation of Schizophyllum commune, with the aim of enhancing anthocyanin solubilization and evaluating anti-inflammatory activity. Response surface methodology was used to optimize fermentation parameters and quantify anthocyanin fractions by HPLC. The anti-inflammatory effect was evaluated using the lipopolysaccharide-induced inflammation model of human foreskin fibroblast (BJ cell), and the interaction of cyanidin-3-O-glucoside (C3G) with NLRP3, a key target of the pyroptosis pathway, was resolved by molecular docking. Our results indicated that the optimal conditions (substrate 3.4%, inoculum 9%, time 50 h) enabled the total anthocyanin to reach 85.1 μg/mL, of which the C3G content was elevated to 66.7 μg/mL (release efficiency of 83.9%). The fermented filtrate effectively promoted BJ cell proliferation and inhibited the lipopolysaccharide-induced inflammatory response, with the pyroptosis signaling pathway playing a significant role. Molecular docking confirmed that C3G binds strongly to the NLRP3 protein. This technology provides a new strategy for high-value utilization of Morus nigra L. residues and the development of natural anti-inflammatory drugs.