RSM and GA-BP assisted optimization of enzyme-ultrasound assisted extraction for mulberry fruit polysaccharides and comparison of their protective effects on NAFLD with hot water extraction polysaccharide.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is triggered by gut-liver axis disorders; enzyme-ultrasound assisted extraction (EAUE) better retains bioactive mulberry polysaccharides (MP) than hot water extraction. This work optimized EAUE by RSM and GA-BP to compare the gut-hepatic protective capacity of two MP preparations and reveal their microecological regulatory mechanism. METHODS: We optimized EAUE conditions and characterized the structural features of EAUE-derived MP (MPEU). A 30-day concurrent modeling and MP-administration mouse trial was conducted with biochemical detection and 16S rRNA sequencing to assess MPEU and hot water extraction MP (MPHW) in vivo activity. RESULTS: RSM yielded predictions closer to experimental values, and its optimal extraction conditions were determined as extraction time 107 min, liquid-to-solid ratio 33:1, enzyme addition amount 350 mg, and extraction temperature 52 °C, yielding MP at 10.06 ± 0.03%. MPEU retained complete glycosidic structures and outperformed MPHW in mitigating hepatic steatosis, intestinal damage and inflammation, by restoring SCFA-producing commensal bacteria and suppressing pro-inflammatory flora. CONCLUSION: In this study, RSM is preferable for EAUE optimization. Structurally intact MPEU exerts stronger NAFLD relief via remodeling gut microecology, promising as nutritional functional food ingredients.