Fucoidan is a sulfated algal polyanionic polysaccharide that possesses many biological activities. In this paper, a fucoidan (SHF) polysaccharide was extracted from Sargassum hemiphyllum collected in the South China Sea. The SHF, with a molecular weight of 1166.48 kDa (44.06%, w/w), consisted of glucose (32.68%, w/w), galactose (24.81%, w/w), fucose (20.75%, w/w), xylose (6.98%, w/w), mannose (2.76%, w/w), other neutral monosaccharides, and three uronic acids, including glucuronic acid (5.39%, w/w), mannuronic acid (1.76%, w/w), and guronuronic acid (1.76%, w/w). The SHF exhibited excellent immunostimulatory activity. An immunostimulating assay showed that SHF could significantly increase NO secretion in macrophage RAW 264.7 cells via upregulation of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) levels based on both gene expression and protein abundance. These results suggest that SHF isolated from Sargassum hemiphyllum has great potential to act as a health-boosting ingredient in the pharmaceutical and functional-food fields.

Morchella esculenta is an edible mushroom with special flavor and high nutritional value for humans, primarily owing to its polysaccharide constituents. M. esculenta polysaccharides (MEPs) possess remarkable pharmaceutical properties, including antioxidant, anti-inflammatory, immunomodulatory, and anti-atherogenic activities. The aim of this study was to evaluate the in vitro and in vivo antioxidant potential of MEPs. In vitro activity was determined using free radical scavenging assays, whereas in vivo activity was evaluated through dextran sodium sulfate (DSS)-induced liver injury in mice with acute colitis. MEPs effectively scavenged 1,1-diphenyl-2-picrylhydrazyl and 2,2-azinobis-6-(3-ethylbenzothiazoline sulfonic acid) free radicals in a dose-dependent manner. Additionally, DSS-induced mice showed severe liver damage, cellular infiltration, tissue necrosis, and decreased antioxidant capacity. In contrast, intragastric administration of MEPs showed hepatoprotective effects against DSS-induced liver injury. MEPs remarkably elevated the expression levels of superoxide dismutase, glutathione peroxidase, and catalase. Additionally, it decreased malondialdehyde and myeloperoxidase levels in the liver. These results indicate that the protective effects of MEP against DSS-induced hepatic injury could rely on its ability to reduce oxidative stress, suppress inflammatory responses, and improve antioxidant enzyme activity in the liver. Therefore, MEPs could be explored as potential natural antioxidant agents in medicine or as functional foods to prevent liver injury.

The COVID-19 pandemic has had a profound impact worldwide, resulting in long-term health effects for many individuals. Recently, as more and more people recover from COVID-19, there is an increasing need to identify effective management strategies for post-COVID-19 syndrome, which may include diarrhea, fatigue, and chronic inflammation. Oligosaccharides derived from natural resources have been shown to have prebiotic effects, and emerging evidence suggests that they may also have immunomodulatory and anti-inflammatory effects, which could be particularly relevant in mitigating the long-term effects of COVID-19. In this review, we explore the potential of oligosaccharides as regulators of gut microbiota and intestinal health in post-COVID-19 management. We discuss the complex interactions between the gut microbiota, their functional metabolites, such as short-chain fatty acids, and the immune system, highlighting the potential of oligosaccharides to improve gut health and manage post-COVID-19 syndrome. Furthermore, we review evidence of gut microbiota with angiotensin-converting enzyme 2 expression for alleviating post-COVID-19 syndrome. Therefore, oligosaccharides offer a safe, natural, and effective approach to potentially improving gut microbiota, intestinal health, and overall health outcomes in post-COVID-19 management.

• A heteropolysaccharide Sargassum Zhangii fucoidan (SZF) has an Mw of 111.28 kDa. • The main monosaccharides of SZF include galactose, fucose, xylose, and uronic acids. • SZF possesses a main chain of (1,4)-α-d-linked-galactose, (3,4)-α-l-fucose, etc. • SZF has significant immune-stimulating properties compared to commercial fucoidans. • SZF has great potential to act as ingredient of functional food or immunodulator.

Morchella esculenta polysaccharides (MEPs) are known to have multiple bioactive properties, including immunomodulatory, anticancer, antioxidant, anti‐inflammatory, etc. In this study, we assessed the impact of MEPs on dextran sulfate sodium (DSS)‐induced colitis in mice, focusing on intestinal barrier and microbiota modulation. Using NMR analysis, MEPs were found to predominantly consist of 1,4,6‐ α ‐ d ‐Glc p and 1,4‐ α ‐ d ‐Glc p . MEPs were able to significantly alleviate weight loss, reduce colon length shortening, and mitigate colon pathology in mice. Notably, MEPs suppressed elevated pro‐inflammatory cytokines levels but boosted anti‐inflammatory cytokine levels. Besides, MEPs modulated gut microbiota, enhancing microbial diversity and promoting homeostasis compared to untreated. Furthermore, there was a higher relative abundance of beneficial bacteria, indicating that MEPs could enhance gut microbiota composition. Collectively, MEPs have promising therapeutic potential in preventing colitis, and therefore could be developed as a novel nutraceutical strategy.