Rosa roxburghii Tratt fruit polysaccharide ameliorates lipid metabolic overload in vitro by synergistically activating AMPK and SIRT1

The rising global prevalence of non-alcoholic fatty liver disease (NAFLD) underscores the urgent need for nutritional strategies for its prevention and management. Although polysaccharides from Rosa roxburghii Tratt fruit (RTFP) have demonstrated various health-promoting properties, their role in regulating NAFLD-associated lipid metabolic overload remains unclear. In this study, crude polysaccharide fractions were extracted from R. roxburghii fruit using alkaline-, acid-, and enzyme-assisted methods, followed by preliminary structural characterization, including chemical composition, molecular weight, and monosaccharide profile. The lipid-lowering activity and underlying mechanism of these crude polysaccharide fractions were investigated using an oleic acid (OA)-induced HepG2 cell model. Results revealed that Al-RTFP (RTFP extracted using alkaline method), through dual activation of AMPK (adenosine 5'-monophosphate (AMP)-activated protein kinase) and SIRT1 (the silent information regulator sirtuin 1), could modulate a lipid metabolism gene network involving ACC , FASN , and CPT1 , concurrently promoting intracellular lipid oxidation while suppressing lipogenesis. Furthermore, this study identified palmitic acid (PA) as exhibiting stronger lipotoxicity than OA. Under PA-induced lipotoxic conditions, Al-RTFP demonstrated the ability to mitigate oxidative stress and preserve mitochondrial function. These findings position Al-RTFP as a promising food-derived candidate for the prevention and management of NAFLD-related lipid metabolic overload.