Dual intestinal-hepatic modulation by phenolic acids improves metabolic-dysfunction associated steatohepatitis

BACKGROUND: Metabolic-dysfunction associated steatohepatitis (MASH) arises from sustained triglyceride overload of the intestine-liver axis, yet current therapies rarely coordinate intestinal lipid entry with hepatic triglyceride disposal. Here we identify a phenolic-acid fraction as a dual-compartment metabolic modulator that couples intestinal lipase inhibition to CPT1α-PPARα-dependent hepatic β-oxidation across species. METHODS: Across species, we investigated the kinetics and metabolic actions of a phenolic fraction (PhAM) using recombinant lipase systems, epithelial transport assays, hepatocyte models, pharmacokinetics, diet-induced metabolic disease paradigms, quantitative histopathology, and a 24-week randomized placebo-controlled clinical trial. RESULTS: PhAM selectively suppresses pancreatic and intestinal lipases non-competitively, lowering V_max with minimal K_m change, resembling some features of orlistat, but via a distinct, non-covalent mechanism. In Caco-2 monolayers and ex vivo loops, it reduces apical-to-basolateral fatty-acid flux, depletes intracellular triglycerides, and limits luminal-to-plasma lipid transfer. PhAM is orally bioavailable, with measurable plasma exposure and prolonged intestinal residence. Under high-fat feeding, it increases fecal fat loss, attenuates post-lipid-load triglyceride excursions, and lowers hepatic triglycerides without altering ApoB secretion. Its triglyceride-lowering effect requires CPT1α-dependent mitochondrial import and PPARα activation, elevates β-hydroxybutyrate, and induces oxidative genes while sparing lipogenesis. In chronic MASH, PhAM reduces steatosis, ballooning, inflammation, and metabolic-dysfunction associated steatotic liver disease (MASLD) Activity Score. A 24-week clinical subgroup, defined by ultrasound and transaminase enrichment, showed dose-responsive improvements in ultrasonographic steatosis and metabolic biomarkers. CONCLUSION: Collectively, these findings define PhAM as a phenolic-acid-based agent that aligns intestinal lipid restriction with hepatic oxidative unloading, offering a mechanistically coherent framework for potentially addressing steatotic liver disease-associated metabolic features.