Bioavailable human metabolites from TOTUM-448 (plant-based formulation) maintain liver cell functionality in a hyperlipidic context that drives MASLD onset

Lipotoxic and inflammatory environment drives metabolic dysfunction-associated steatotic liver disease (MASLD) onset. As most conventional treatments present adverse side effects, alternative options such as preventive nutritional interventions have been developed, though further clinical validation is needed. In this study, we conducted an innovative ex vivo clinical investigation to examine how circulating metabolites generated after oral intake of TOTUM-448 (a plant-based, polyphenol-rich formulation) may influence hepatocyte function. UHPLC-MS/MS analysis confirmed and characterized the bioavailable polyphenol metabolites present in human serum. This metabolite-enriched serum was further used to treat HepG2 hepatocytes, with or without palmitate pretreatment (250 µM). The effects of TOTUM-448–derived metabolites on hepatocytes were evaluated by monitoring cell viability, lipid metabolism, inflammation, oxidative stress, and endoplasmic reticulum (ER) stress, all of which are central features of MASLD. Treated hepatocytes exhibited resistance to palmitate-induced lipotoxic stress, showing reduced intracellular lipid accumulation. TOTUM-448–derived metabolites also prevented the palmitate-induced upregulation of inflammatory gene expression. Additionally, while palmitate strongly upregulated CHOP and XBP1 mRNA expression as well as ATF6 and Caspase-3 activities, the presence of TOTUM-448–derived metabolites restored these ER stress markers to normal levels.