Preparation and characterisation of a novel hydrogel based on Auricularia polytricha β-glucan and its bio-release property for vitamin B12 delivery

Research progress on natural β-glucan in intestinal diseases

β-Glucan, an essential natural polysaccharide widely distributed in cereals and microorganisms, exhibits extensive biological activities, including immunoregulation, anti-inflammatory, antioxidant, antitumor properties, and flora regulation. Recently, increasing evidence has shown that β-glucan has activities that may be useful for treating intestinal diseases, such as inflammatory bowel disease (IBD), and colorectal cancer. The advantages of β-glucan, which include its multiple roles, safety, abundant sources, good encapsulation capacity, economic development costs, and clinical evidence, indicate that β-glucan is a promising polysaccharide that could be developed as a health product or medicine for the treatment of intestinal disease. Unfortunately, few reports have summarized the progress of studies investigating natural β-glucan in intestinal diseases. This review comprehensively summarizes the structure-activity relationship of β-glucan, its pharmacological mechanism in IBD and colorectal cancer, its absorption and transportation mechanisms, and its application in food, medicine, and drug delivery, which will be beneficial to further understand the role of β-glucan in intestinal diseases.

Structural Characteristics, Rheological Properties, and Antioxidant Activity of Novel Polysaccharides from “Deer Tripe Mushroom”

The polysaccharide was extracted by water extraction and alcohol precipitation method from “deer tripe mushroom,” which was domesticated and bred from wild Auricularia delicata in Zambia. The structure of the deer tripe mushroom polysaccharide (DTMP) was characterized by gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), scanning electron microscope (SEM), and other analytical techniques. And the rheological and gel properties and antioxidant capacities of the polysaccharide were studied. The results showed that DTMP was mainly composed of mannose, fructose, glucose, and galacturonic acid, of which the galacturonic acid was the main component. By calculation, the molar ratio of mannose : fructose : glucose : galactoacid in DTMP is 0.8 : 14.8 : 1.0 : 26.32. The polysaccharide was mainly composed by α-1,4-glycosidic bond. DTMP solution showed a shear-thinning (pseudoplastic) behaviour, and its pseudoplasticity was more obvious at a concentration of 2%. The power law model was used to evaluate the viscosity curves of DTMP, and its viscosity and consistency indices both increased as the concentration increased, whereas both indices decreased as the concentration decreased. The viscosity of the polysaccharide solution changed as the pH changed: the polysaccharide solutions had a higher viscosity at pH = 10. DTMP showed gel-like behaviour (G′ ＞ G″), and the gel strength enhanced with the increase of concentration (2%–10%). In addition, the antioxidant experiment of DTMP showed that it had good antioxidant activity, and there was a significant dose-effect relationship between its activity and concentration in the low concentration range.

Potential of Nanonutraceuticals in Increasing Immunity

Nutraceuticals are defined as foods or their extracts that have a demonstrably positive effect on human health. According to the decision of the European Food Safety Authority, this positive effect, the so-called health claim, must be clearly demonstrated best by performed tests. Nutraceuticals include dietary supplements and functional foods. These special foods thus affect human health and can positively affect the immune system and strengthen it even in these turbulent times, when the human population is exposed to the COVID-19 pandemic. Many of these special foods are supplemented with nanoparticles of active substances or processed into nanoformulations. The benefits of nanoparticles in this case include enhanced bioavailability, controlled release, and increased stability. Lipid-based delivery systems and the encapsulation of nutraceuticals are mainly used for the enrichment of food products with these health-promoting compounds. This contribution summarizes the current state of the research and development of effective nanonutraceuticals influencing the body's immune responses, such as vitamins (C, D, E, B12, folic acid), minerals (Zn, Fe, Se), antioxidants (carotenoids, coenzyme Q10, polyphenols, curcumin), omega-3 fatty acids, and probiotics.

β-glucan as a new tool in vaccine development

Vaccination constitutes one of the major breakthroughs in human medicine. At the same time, development of more immunogenic vaccine alternatives to using aluminium-based adjuvants is one of the most important phases of vaccination development. Among different sources of carbohydrate polymers, including plants, microbes and synthetic sources tested, glucans were found to be the most promising vaccine adjuvant, as they alone stimulate various immune reactions including antibody production without any negative side effects. The use of glucan particles as a delivery system is a viable option based on the documented efficient antigen loading and receptor-targeted uptake in antigen-presenting cells. In addition to particles, soluble glucans can be used as novel hydrogels or as direct immunocyte-targeting delivery systems employing novel complexes with oligodeoxynucleotides. This review focuses on recent advances in glucan-based vaccine development from glucan-based conjugates to a glucan-based delivery and adjuvant platform.