School of Food and Biological Engineering, Hefei University of Technology, Hefei, P.R. China.
Teaching and Research Section of Clinical Nursing, Xiangya Hospital, Central South University, Changsha, China.
J Sci Food Agric. 2023 Jul;103(9):4401-4412. doi: 10.1002/jsfa.12513. Epub 2023 Mar 13.
Novel functional polysaccharides from fungi are important nutraceuticals. An exopolysaccharide, Morchella esculenta exopolysaccharide (MEP 2), was extracted and purified from the fermentation liquor of M. esculenta. The aim of this study was to investigate its digestion profile, antioxidant capacity, and effect on the microbiota composition in diabetic mice.
The study found that MEP 2 was stable during in vitro saliva digestion but was partially degraded during gastric digestion. The digest enzymes exerted a negligible effect on the chemical structure of MEP 2. Molecular weight and atomic force microscope (AFM) images suggest that both smaller chains and larger aggregations were produced. Scanning electron microscope (SEM) images reveal that the surface morphology was much altered after intestinal digestion. After digestion, the antioxidant ability increased as revealed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. Both MEP 2 and its digested components showed strong α-amylase and moderate α-glucosidase inhibition activity, leading us to further investigate its ability to modulate the diabetic symptoms. The MEP 2 treatment ameliorated the inflammatory cell infiltration and increased the size of pancreas inlets. Serum concentration of HbA1c was significantly reduced. Blood glucose level during the oral glucose tolerance test (OGTT) was also slightly lower. The MEP 2 increased the diversity of the gut microbiota and modulated the abundance of several important bacteria including Alcaligenaceae, Caulobacteraceae, Prevotella, Brevundimonas, Demequina, and several Lachnospiraceae species.
It was found that MEP 2 was partially degraded during in vitro digestion. Its potential antidiabetic bioactivity may be associated with its α-amylase inhibition and gut microbiome modulation ability. © 2023 Society of Chemical Industry.
真菌来源的新型功能性多糖是重要的营养保健品。从羊肚菌发酵液中提取并纯化得到一种胞外多糖，羊肚菌胞外多糖（MEP2）。本研究旨在探讨其在糖尿病小鼠体内的消化谱、抗氧化能力及对肠道微生物组成的影响。
研究发现，MEP2 在体外唾液消化过程中稳定，但在胃消化过程中部分降解。消化酶对 MEP2 的化学结构几乎没有影响。分子量和原子力显微镜（AFM）图像表明，产生了更小的链和更大的聚集物。扫描电子显微镜（SEM）图像显示，经肠道消化后，表面形态发生了很大改变。消化后，2,2-二苯基-1-苦基肼基（DPPH）和 2,2′-联氮-双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）测定显示其抗氧化能力增强。MEP2 及其消化产物均表现出较强的α-淀粉酶和中等强度的α-葡萄糖苷酶抑制活性，因此我们进一步研究了其调节糖尿病症状的能力。MEP2 治疗改善了炎症细胞浸润，并增加了胰岛入口的大小。糖化血红蛋白（HbA1c）血清浓度显著降低。口服葡萄糖耐量试验（OGTT）期间的血糖水平也略有降低。MEP2 增加了肠道微生物群的多样性，并调节了包括 Alcaligenaceae、Caulobacteraceae、Prevotella、Brevundimonas、Demequina 和几个 Lachnospiraceae 物种在内的几种重要细菌的丰度。
发现 MEP2 在体外消化过程中部分降解。其潜在的抗糖尿病生物活性可能与其α-淀粉酶抑制和肠道微生物组调节能力有关。
