树莓低聚糖ERP-1结构表征及体外免疫调节活性研究OA

In this study,an oligosaccharide named ERP-1 was isolated from raspberry(Rubus idaeus L.)fruits.Its chemical struc-ture was elucidated,and in vitro immunomodulatory activity was evaluated.Crude polysaccharides were extracted from raspberry fruits u-sing a multi-enzyme method and further purified by DEAE-52 cellulose column chromatography to obtain the purified fraction ERP-1.The molecular weight,degree of polymerization(DP),functional groups,monosaccharide composition,and glycosidic linkages of ERP-1 were characterized by high-performance gel permeation chromatography(HPGPC),ultra performance liquid chromatography-tandem mass(UP-LC-MS/MS),fourier transform infrared spectroscopy(FT-IR),ion chromatography(IC),and gas chromatography-mass spectrometry(GC-MS).In vitro immunomodulatory activity was evaluated using murine macrophage RAW264.7 cells.The results showed that ERP-1 had a molecular weight of 569 Da and a Dp ranging from 3 to 7.It was composed of glucose(Glc),fructose(Fru),and mannose(Man)at a molar ratio of 0.582:0.371:0.048.Five types of glycosidic linkages were identified,among which →4)-Glcp-(1→ was the most abundant.Notably,ERP-1 significantly reduced the secretion and mRNA expression of nitric oxide(NO),tumor necrosis factor-α (TNF-α),interleukin-6(IL-6),and interleukin-1 β(IL-1 β)in lipopolysaccharide(LPS)-stimulated RAW264.7 cells.Conversely,it also enhanced the production and mRNA expression of these cytokines in non-LPS-stimulated RAW264.7 cells.These findings could indi-cate that ERP-1 is an oligosaccharide with immunomodulatory activity in vitro and holds promising potential for applications in functional foods and pharmaceutical products.