Lonicerae flos polysaccharides improve nonalcoholic fatty liver disease by activating the adenosine 5'-monophosphate-activated protein kinase pathway and reshaping gut microbiota.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver cirrhosis and cancer. Lonicerae flos polysaccharides (LPs) have been shown to be effective in treating metabolic diseases; however, the therapeutic effects and underlying molecular mechanisms of LPs in NAFLD remain unclear. PURPOSE: The objective of this study was to investigate the morphological characterization of Lonicerae flos polysaccharides (LPs) and the mechanism of LPs in relieving NAFLD. METHODS: The morphology of LPs was observed using atomic force microscopy (AFM), X-ray diffraction (XRD), thermal weight (TG), and thermal weight derivative (DTG); NAFLD mice were treated with LPs at the same time as they were induced with a Western diet, and then the indexes related to glycolipid metabolism, fibrosis, inflammation, and autophagy in the serum and liver of the mice were detected. RESULTS: The atomic force microscope analysis results indicated that the LPs displayed sugar-chain aggregates, exhibited an amorphous structure, and were relatively stable in thermal cracking at 150 °C. It was also found that LPs exerted therapeutic effects in NAFLD. The LPs prevented high-fat and -cholesterol diet-induced NAFLD progression by regulating glucose metabolism dysregulation, insulin resistance, lipid accumulation, inflammation, fibrosis, and autophagy. Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) inhibitor compound C abrogated LP-induced hepatoprotection in mice with NAFLD. The LPs further treated NAFLD by reshaping the structure of the gut microbiota, in which Desulfovibrio bacteria plays a key roles. CONCLUSION: Lonicerae flos polysaccharides exert protective effects against NAFLD in mice by improving the structure of the intestinal flora and activating the AMPK signaling pathway. © 2023 Society of Chemical Industry.

A novel purgative mechanism of multiflorin A involves changing intestinal glucose absorption and permeability.

BACKGROUND: Multiflorin A (MA) is a potential active ingredient of traditional herbal laxative, Pruni semen, with unusual purgative activity and an unclear mechanism, and inhibiting intestinal glucose absorption is a promising mechanism of novel laxatives. However, this mechanism still lacks support and a description of basic research. PURPOSE: This study aimed to determine the main contribution of MA to the purgative activity of Pruni semen and elucidate the effect intensity, characteristics, site, and mechanism of MA in mice, and determine the novel mechanism of traditional herbal laxatives from the perspective of intestinal glucose absorption. METHODS: We induced diarrhoea in mice by administering Pruni semen and MA, and the defecation behaviour, glucose tolerance, and intestinal metabolism were analysed. The effects of MA and its metabolite on peristalsis of the intestinal smooth muscle were evaluated using an intestinal motility assay in vitro. Intestinal tight junction proteins, aquaporins, and glucose transporters expression were analysed using immunofluorescence; gut microbiota and faecal metabolites were analysed using 16S rRNA and liquid chromatography-mass spectrometry. RESULTS: MA administration (20 mg/kg) induced watery diarrhoea in over half of the experimental mice. The activity of MA in lowering peak postprandial glucose levels was synchronous with purgative action, with the acetyl group being the active moiety. MA was metabolised primarily in the small intestine, where it decreased sodium-glucose cotransporter-1, occludin, and claudin1 expression, then inhibited glucose absorption, resulting in a hyperosmotic environment. MA also increased the aquaporin3 expression to promote water secretion. Unabsorbed glucose reshapes the gut microbiota and their metabolism in the large intestine and the increasing gas and organic acid promoted defecation. After recovery, the intestinal permeability and glucose absorption function returned, and the abundance of probiotics such as Bifidobacterium increased. CONCLUSION: The purgative mechanism of MA involves inhibiting glucose absorption, altering permeability and water channels to promote water secretion in the small intestine, and regulating gut microbiota metabolism in the large intestine. This study is the first systematic experimental study on the purgative effect of MA. Our findings provide new insight into the study of novel purgative mechanisms.