为了研究白莲莲子皮多糖的理化性质并评价其生物活性，以白莲莲子皮为原料，采用水提醇沉法获得白莲莲子皮粗多糖(LSSCP)，再采用Sevage试剂脱蛋白、脱色和透析法对白莲莲子皮粗多糖进行纯化，得到白莲莲子皮多糖(LSSP)。采用红外光谱以及气相色谱对莲子皮多糖的理化性质进行了研究。通过还原能力测定、DPPH自由基和·OH自由基的清除能力评价LSSP的体外抗氧化能力；通过体外实验评估LSSP对RAW264.7巨噬细胞免疫调节活性。结果表明，所得LSSP的得率为3.72%，多糖含量为86.79%；LSSP单糖组成分析表明，LSSP主要由鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖、半乳糖组成，摩尔比为2.23: 3.47: 1.00: 3.08: 4.27: 7.00。红外光谱分析表明LSSP呈现出多糖类物质的典型特征吸收峰。体外抗氧化实验结果表明，LSSP具有良好的还原能力和清除DPPH、·OH自由基的能力。LSSP可通过刺激巨噬细胞释放NO和细胞因子（TNF-α、IL-6、IL-1β）来增强免疫调节活性，在添加LSSP浓度为200 μg/mL时，NO、TNF-α、IL-6和IL-1β的分泌量达到了最大值，与空白组相比，NO、TNF-α、IL-6和IL-1β的分泌量分别增加了48.86 μM、98.75 ng/mL、85.64 ng/mL和46.67 ng/mL。结果表明，莲子皮多糖可作为一种新型的功能性食品免疫调节剂，对于莲子皮资源开发提供理论依据。

The physicochemical properties of white lotus seed skin were investigated and the biological activities of lotus seed skin complex polysaccharides (LSSCP) were evaluated. To obtain LSSP, seed skin was water extracted, alcohol precipitated, and purified by deproteinization using Sevage reagent, decolorized, and dialyzed. The physicochemical properties were determined and analyzed by infrared spectroscopy and gas chromatography. Antioxidant capacities of LSSP in vitro were evaluated according to their reducing capacities and DPPH and OH radical scavenging abilities. Immunomodulatory activities on RAW264.7 macrophages were investigated. The yield and polysaccharide content of LSSP was 3.72% and 86.79%, respectively. Monosaccharide composition analysis revealed that LSSP was comprised mainly of rhamnose, arabinose, xylose, mannose, glucose and galactose at a molar ratio of 2.23: 3.47: 1.00: 3.08: 4.27: 7.00. Infrared spectroscopy analysis indicates the presence of typical absorption peaks indicative of polysaccharides in LPPS. In vitro antioxidant capacity tests demonstrated good reducing power and scavenging activities of LPPS on DPPH and OH radicals. LSSP enhanced immunoregulatory activities by stimulating macrophages to release NO and cytokines (TNF-α, IL-6, and IL-1β). Secretion of all these molecules was the greatest when the concentration of LSSP was 200 μg/mL. Compared with the control group, LSSP increased the secretion of NO, TNF-α, IL-6, and IL-1β by 48.86 μM, 98.75 ng/mL, 85.64 ng/mL, and 46.67 ng/mL, respectively. The collective results implicate LSSP as a potentially novel immunomodulatory supplement. The findings provide a theoretical basis for future studies involving white lotus seed skins.

江西省杰出青年人才资助计划项目（20192BCB23027）；江西省重点研发计划项目（20192BBF60041；20202BBFL63035）；江西省科学院重大科研开发专项项目（2020-YZD-1）