Structural characterization of a pectic polysaccharide from Rubus chingii Hu. unripe fruits and its efficacy in inhibiting intestinal lipid absorption in vivo
Xingxing Wang, Yupeng Liu, Yongbin Xu, Siqi Gao, Qiuying Xu, Huan Gong, Lumeng Yao, Songshan Shi, Shunchun Wang, Huijun Wang, Luping Qin, Jianjun Wu
Abstract
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.