Structural characteristics and structure-activity relationship of four polysaccharides from Lycii fructus.

At present, the structure-activity relationship of polysaccharides is a common and important focus in the fields of glycobiology and carbohydrate chemistry. To better understand the effect of specific polysaccharide structures on bioactive orientation, four homogeneous polysaccharides from Lycii fructus, one neutral along with three acidic polysaccharides, were purified, structurally characterized and comparatively evaluated on the antioxidative and anti-aging activities. The GC-MS-based monosaccharide composition analysis and methylation results showed that the LFPs had similar glycosyl types but varied proportions. Nuclear magnetic resonance (NMR) spectroscopy showed that LFPs consisted of arabinogalactan, rhamnogalacturonan and homogalacturonan structural domains. The results of the structure-activity relationship indicated that the antioxidative activity was positively correlated with the galacturonic acid (GalA) content, while the neutral multi-branched chains might be responsible for the anti-aging activity. This study is the first time to compare the principal structures and multiple biological activities of LFPs, which provided a reference for the industrial development and deep excavation of the health value of LFPs.

Immunomodulatory and antiviral effects of Lycium barbarum glycopeptide on influenza a virus infection.

Influenza is caused by a respiratory virus and has a major global impact on human health. Influenza A viruses in particular are highly pathogenic to humans and have caused multiple pandemics. An important consequence of infection is viral pneumonia, and with serious complications of excessive inflammation and tissue damage. Therefore, simultaneously reducing direct damage caused by virus infection and relieving indirect damage caused by excessive inflammation would be an effective treatment strategy. Lycium barbarum glycopeptide (LbGp) is a mixture of five highly branched polysaccharide-protein conjuncts (LbGp1-5) isolated from Lycium barbarum fruit. LbGp has pro-immune activity that is 1-2 orders of magnitude stronger than that of other plant polysaccharides. However, there are few reports on the immunomodulatory and antiviral activities of LbGp. In this study, we evaluated the antiviral and immunomodulatory effects of LbGp in vivo and in vitro and investigated its therapeutic effect on H1N1-induced viral pneumonia and mechanisms of action. In vitro, cytokine secretion, NF-κB p65 nuclear translocation, and CD86 mRNA expression in LPS-stimulated RAW264.7 cells were constrained by LbGp treatment. In A549 cells, LbGp can inhibit H1N1 infection by blocking virus attachment and entry action. In vivo experiments confirmed that administration of LbGp can effectively increase the survival rate, body weight and decrease the lung index of mice infected with H1N1. Compared to the model group, pulmonary histopathologic symptoms in lung sections of mice treated with LbGp were obviously alleviated. Further investigation revealed that the mechanism of LbGp in the treatment of H1N1-induced viral pneumonia includes reducing the viral load in lung, regulating the phenotype of pulmonary macrophages, and inhibiting excessive inflammation. In conclusion, LbGp exhibits potential curative effects against H1N1-induced viral pneumonia in mice, and these effects are associated with its good immuno-regulatory and antiviral activities.

Corrigendum: Lycium barbarum Glycopeptide prevents the development and progression of acute colitis by regulating the composition and diversity of the gut microbiota in mice.

[This corrects the article DOI: 10.3389/fcimb.2022.921075.].

Lycium barbarum Glycopeptide prevents the development and progression of acute colitis by regulating the composition and diversity of the gut microbiota in mice.

In most cases, recurrent chronic colitis is caused by the recurrence of acute colitis after incomplete recovery and re-exposure to irritating factors, and the gut microbiome, which is the largest micro-ecosystem in the human body, plays a crucial role in the development of colitis. Plant polysaccharides have always been reported to have the ability for anti-inflammation, and they are closely related to the gut microbiome. Lycium barbarum Glycopeptide (LbGP), the most potent component obtained by further isolation and purification from Lycium barbarum fruit, has been shown to inhibit inflammation in animal models. However, its therapeutic efficacy in colitis and its mechanism in gut microbiota regulation have not been fully studied. In our study, the dextran sulfate sodium (DSS)-induced mouse model was used to dynamically evaluate the effect of LbGP in the treatment of acute colitis and the mechanism from the perspective of the gut microbiome through the 16S rDNA sequence. The results showed that LbGP treatment significantly alleviated acute colitis and improved the gut microbiome compared with that in the model group. Harmful bacteria, such as Lachnoclostridium spp. and Parabacteroides_distasonis, were inhibited and probiotics, such as Bacteroides_acidifaciens, Lactobacillus spp., Turicibacter spp., and Alistipes spp., were increased by LbGP treatment. Further, a Random Forest analysis with 10-fold cross-validation identified a family named Muribaculaceae representing colitis development and recovery upon LbGP treatment. In conclusion, our study demonstrated the capability of LbGP to prevent the development of acute colitis by regulating the composition and diversity of the gut microbiota and highlighted the dynamic process of gut microbiota with the colitis progression. Further, it provides evidence to develop LbGP as a functional food supplement and future drug acting on intestinal disease.