Lycium barbarum L. is traditionally used as a medicinal and food resource in China. Spray dried powder of its fresh fruits is widely used as a food product or a functional food ingredient. In this study, the immunoregulatory effects of Lycium barbarum L. powder (LB), Lycium barbarum L. polysaccharides (LBP) and their mixture (LB + LBP) on cyclophosphamide (CTX)-induced immunosuppressive mice were investigated, as well as their influences on gut microbiota homeostasis. The results showed that LB, LBP and their combination restored the body mass and food intake of immunosuppressed mice to different degrees, improved spleen, thymus and colon injury, effectively promoted the secretion of cytokines including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interferon-γ (IFN-γ) and immunoglobulin (Ig) A in immunosuppressed mice, regulated the expression of immune-related genes in the colon, promoted the generation of short chain fatty acids (SCFAs), significantly modulated the relative abundance of Muribaculaceae_unclassified, Muribaculum, Mucispirillum, Helicobacter, Bilophila and Clostridiales (P < 0.05), and reversed the abnormal metabolic function of the gut microbiota induced by CTX. Moreover, compared with LBP, LB and LB + LBP decreased the relative abundance of Clostridiales and increased the relative abundance of the beneficial bacterium Duncaniella, and LB + LBP also decreased the relative abundance of Anaerotruncus. The results of this study will provide a theoretical basis for the research and development of specific health products and diversified products in the Lycium barbarum L. processing industry.

In the present study, a method for enzymatically digesting N-glycolylneuraminic acid (Neu5Gc) in bovine immunoglobulin G (bIgG) and then ligating the IgG with human N-acetylneuraminic acid (Neu5Ac) was developed to transform bIgG into human IgG (hIgG), and conditions for preparing a crystallizable fragment (Fc) from hIgG were explored. Results showed that hIgG was prepared by digesting Neu5Gc in bIgG (4 mg/mL) with 170 U/mL neuraminidase and subsequently transferring 8.4 galactose (Gal) residues and 42 Neu5Ac residues into the digested IgG with β-1,4-galactosyltransferase (B4GALT1) and α-2,6-sialyltransferase (ST6GAL1), respectively. Further, a highly pure Fc fragment from hIgG was prepared under the conditions: hIgG concentration 10 mg/mL, papain/hIgG ratio 0.05 (m/m), cysteine concentration 10.0 mmol/L, EDTA concentration 2.0 mmol/L, pH 7.0, and hydrolysis time 3 h. The yields of glycosylated hIgG and Fc fragment were 71.7% and 20.8%, respectively. The results of the present study can provide a scientific basis for the development and nutritional evaluation of bIgG-based products.

Fuzhuan Brick Tea (FBT), a traditional Chinese post-fermented tea, is mainly made from leaves of the plant Camellia sinensis with higher maturity. FBT is an essential nutritional supplement for the ethnic groups living in the border regions of China. In the process of FBT processing, unique golden yellow particles are produced on the surface and inside of FBT by the fermentation of Aspergillus cristatus, FBT has many pharmacological functions such as anti-oxidation, anti-obesity, lowering blood sugar, anti-inflammatory, and regulating gut microbiota. Among them, regulating lipid metabolism and gut microbiota are the two most important active functions of FBT. This paper summarized the research on the regulation of lipid metabolism and gut microbiota of FBT, in order to increase the understanding of the pharmacological functions of FBT and promote the further research of FBT.

Kudingcha is a Chinese traditional medicinal and edible natural plant with important medicinal and health value. Kudingcha made from Ilex plants, namely large leaf Kudingcha, is the most widely accepted and consumed Kudingcha variety. Large leaf Kudingcha is rich in various bioactive components, such as polyphenols and polysaccharides, and it has diverse biological functions, including antioxidant activity, prevention of hyperlipidemia, protection of liver and heart. Compared to tea polysaccharides and large leaf Kudingcha phenolics, the research about large leaf Kudingcha polysaccharides is scarce up to now, and it is worthy of further investigation. This manuscript systematically analyzed the publication about large leaf Kudingcha polysaccharides, and reviewed its extraction, isolation and purification, structure characterization, and biological activities. Hot water extraction -ethanol precipitation was the main method for extracting large leaf polysaccharides, and they were mostly purified by anion-exchange chromatography coupled ethanol fractional precipitation and gel chromatography. Large leaf Kudingcha polysaccharides were composed of arabinose, galactose, glucose, galacturonic acid, rhamnose, etc., and had antioxidant, antibacterial, immune regulating and liver protecting activities. This paper provided the consulting and guideline for further research, development and utilization of large leaf Kudingcha polysaccharides.

Western diet (rich in highly refined sugar and fat) can induce a range of metabolic dysfunctions in animals and humans, including neuroinflammation and cognitive function decline. Neuroinflammation and cognitive impairment, two critical pathological characteristics of Alzheimer’s disease, have been closely associated with microbial alteration via the gut-brain axis. Thus, the present study aimed to investigate the influence of 2-O-β-D-glucopyranosyl-L-ascorbic acid (AA-2βG) isolated from the fruits of Lycium barbarum on preventing the high-fructose diet (HFrD) induced neuroinflammation in mice. It was found that AA-2βG prevented HFrD-induced cognitive deficits. AA-2βG also predominantly enhanced the gut barrier integrity, decreased lipopolysaccharide entry into the circulation, which subsequently countered the activation of glial cells and neuroinflammatory response. These beneficial effects were transmissible by horizontal fecal microbiome transplantation, transferring from AA-2βG fed mice to HFrD fed mice. Additionally, AA-2βG exerted neuroprotective effects involving the enrichment of Lactobacillus and Akkermansia, potentially beneficial intestinal bacteria. The present study provided the evidence that AA-2βG could improve indices of cognition and neuroinflammmation via modulating gut dybiosis and preventing leaky gut. As a potential functional food ingredient, AA-2βG may be applied to attenuate neuroinflammation associated with Western-style diets.

Theasinensin A (TSA), a dimer of epigallocatechin gallate, has been preliminarily demonstrated to have hypoglycemia and anti-inflammatory effects. However, little information is available on its potential mechanisms of anti-diabetes. Therefore, the present study aimed to investigate the influence of TSA on glucose and lipid metabolism and gut microbiota in high-fat-diet/streptozotocin-induced diabetic mice. As result, TSA improved polydipsia, polyphagia and impaired glucose tolerance of diabetic mice, declined the fasting blood glucose and hepatic triglyceride level, and enhanced the expression at mRNA level of insulin receptor substrate, phosphoinositide 3-kinase, protein kinase B and glucagon-like peptide 1 receptor (GLP-1R) in the diabetic liver. Moreover, TSA could restore the disorder of gut microbiota of diabetic mice. High-dose (100 mg/kg) TSA showed better beneficial effects from the blood biochemical parameters, hepatic function and gut microbiota. In general, high-dose TSA significantly modulated gut microbiota by increasing the relative abundance of Akkermansia and decreasing the relative abundances of Acetatifactor, Anaerotruncus, Pseudoflavonifactor, Oscillibacter and Clostridium clusters. The results indicated that TSA could exert an anti-diabetes effect in diabetic mice through restoring glucose homeostasis, declining hepatic steatosis, activating insulin and GLP-1 signaling pathways, and ameliorating gut microbiota dysbiosis.

Polysaccharides from Fuzhuan brick tea (FBTPS), one of most important bioactive components in tea, showed various health-promoting functions. Our previous work demonstrated that the crude FBTPS (CFBTPS) could modulate the gut microbiota. However, which purified fraction in CFBTPS contributing to the modulation of gut microbiota remains unclear. Thus, the fermentation characteristics and probiotic activity of a purified fraction (FBTPS-2-1) of CFBTPS were evaluated in this work. The results showed that gut microbiota could utilize FBTPS-2-1 to produce short-chain fatty acids including acetic, propionic, n-butyric and n-valeric acids. FBTPS-2-1 could modulate the structure and metabolic pathways of gut microbiota. FBTPS-2-1 could increase the health-promoting gut microbiota such as Prevotellaceae and Bifidobacteriaceae, and decreased the harmful bacteria such as Enterobacteriaceae and Fusobacteriaceae. The results of metagenomics showed that Prevotella copri and Megamonas funiformis were the dominant bacteria after fermentation of FBTPS-2-1. Furthermore, FBTPS-2-1 could regulate the biosynthesis and metabolism pathways of gut microbiota. Thus, the enrichment of food with FBTPS-2-1 is expected as a potential strategy for promoting human health due to modulation of gut microbiota.