Structural characterization of a pectic polysaccharide from Rubus chingii Hu. unripe fruits and its efficacy in inhibiting intestinal lipid absorption in vivo

Excessive lipid intake is a major contributor to obesity, and inhibiting intestinal lipid absorption is considered an effective strategy to mitigate this condition. In this study, a pectic polysaccharide designated as RCP-2-3 was obtained from Rubus chingii Hu. unripe fruits and its potential inhibitory effect on intestinal lipid absorption in vivo was investigated. Structural studies revealed that RCP-2-3 (8.54 kDa) is a homogeneous pectic polysaccharide composed of homogalacturonan (HG) and rhamnogalacturonan II (RG-II) domains in a 4.4:4.1 mass ratio. Treatment with RCP-2-3 for 7 days effectively reduced postprandial serum triglyceride (TG) accumulation and lipid absorption in BODIPY-labeled soybean oil-fed mice, accompanied by increased lipid excretion. Specifically, RCP-2-3 increased the excretion of long-chain fatty acids in dietary lipids, such as linoleic acid, oleic acid, palmitic acid, and stearic acid. A 28-day administration of RCP-2-3 reduced weight gain and improved dyslipidemia, and promoted lipid excretion in mice subjected to a high-fat diet and high-fat emulsion. In conclusion, RCP-2-3, a natural pectic polysaccharide consisting of HG and RG-II domains, effectively inhibited intestinal lipid absorption and reduced obesity-related parameters. These findings highlight the potential of RCP-2-3 for application in both the food and pharmaceutical industries.