Receptor basis of biological activity of polysaccharides

Polysaccharides with antioxidant activity: Extraction, beneficial roles, biological mechanisms, structure-function relationships, and future perspectives: A review

Polysaccharides are valuable macromolecules due to their multiple bioactivities, safety, and a wide range of sources. Recently, a series of polysaccharides with antioxidant activity have been intensively reported. In this review, the latest advances in polysaccharides with antioxidant activity have been reviewed, primarily based on the investigations of polysaccharides regarding advanced extraction methods, roles in oxidative stress-related diseases, intracellular signaling pathways associated with antioxidant responses, activating pathways in the gut, structure-function relationships, and methods to improve antioxidant activity. The summarized information highlighted that much work needs to be conducted, from laboratory to industry, to understand and fully utilize the antioxidant potential of polysaccharides. Finally, future perspectives, including scaling-up of advanced extraction methods, standardizing the protocols for assessing and screening polysaccharides, bridging gaps on the biological mechanisms underlying antioxidant activity, performing clinical trials, and elucidating structure-antioxidant relationships, have been addressed. The information present in this review will be helpful to the scientific community when studying on polysaccharides with antioxidant potential and provides research directions for a better understanding of the polysaccharides and promotes their successful applications in functional foods and nutraceuticals.

Ultrasound-assisted H2O2 degradation enhances the bioactivity of Schizophyllan for wound healing and tissue regeneration

Background

Schizophyllan (SPG), a bioactive polysaccharide from Schizophyllum commune, possesses significant anti-inflammatory, antioxidant, and immunomodulatory properties. The molecular weight of polysaccharides significantly impacts their structural properties and biological functions. However, the functional characteristics of low molecular weight polysaccharides derived from Schizophyllum commune remain inadequately explored.

Methods

This study developed an ultrasound-assisted hydrogen peroxide (H2O2) degradation method to produce low-molecular-weight SPG with enhanced bioactivity. The process was optimized using response surface methodology, focusing on ultrasound duration, ultrasonic power, and H2O2 concentration. This approach effectively reduced the molecular weight of SPG from 4,409,608 Da to 257,500 Da, yielding three distinct variants: SPG-a (257,500 Da), SPG-b (429,300 Da), and SPG-c (364,800 Da). The bioactivity of these variants was assessed through in vitro cell proliferation and migration assays using BJ and HaCaT cells, as well as an in vivo zebrafish larval caudal fin regeneration model.

Results

In vitro, SPG-b significantly promoted cell proliferation, increasing BJ and HaCaT cells growth by 53.69% and 14.59%, respectively, at a concentration of 300 μg/mL (p < 0.05), compared to undegraded SPG. Additionally, scratch assays revealed that SPG-a enhanced BJ cells migration by 24.13% (p < 0.05), while SPG-b exhibited most pronounced effect on HaCaT cells migration (17.12%, p < 0.05), compared to the undegraded SPG. In vivo, SPG-c (3.125 mg/mL) significantly improved fin regeneration rates by 6.97% (p < 0.05) in zebrafish larvae, compared to the undegraded SPG.

Conclusion

This study demonstrates that ultrasound-assisted H2O2 degradation effectively reduces SPG molecular weight while enhancing its functional properties. These findings provide a foundation for the further development of SPG in pharmaceutical and cosmetic applications, highlighting its potential for broader utilization.

Bacterial exopolysaccharides: Characteristics and antioxidant mechanism

Bacterial exopolysaccharides (EPS) are secondary metabolites of microorganisms which play important roles in adhesion, protection, biofilm formation, and as a source of nutrition. Compared with polysaccharides obtained from animal and plant species, bacterial polysaccharides have significant advantages in terms of production cost and large-scale production due to their abundant metabolic pathways and efficient polysaccharide production capacity. Most extracellular polysaccharides are water-soluble, and some are insoluble, such as bacterial cellulose. Some soluble bacterial EPS also have biological activities such as anticancer, antioxidant, antibacterial and immunomodulatory activities. These biological activities are mainly affected by the molecular weight, monosaccharide type, composition and structure of EPS. In recent years, bacterial EPS are considered as novel functional polysaccharides with important application prospects, especially in free radical scavenging and antioxidation. This review focuses on the characteristics of bacterial EPS, their ability to scavenge free radicals and their corresponding antioxidant mechanisms, and summarizes the relationship between different structures (such as monosaccharide composition, functional groups, molecular weight, etc.) and antioxidant activities. It provides a new idea for the development of more bioactive bacterial EPS antioxidants, points out a new direction for the commercial production of natural, safe and economical polysaccharide drugs and health products.

Polysaccharide from Helianthus tuberosus L. as a potential radioprotector

INTRODUCTION

Radioprotectors help to protect the body or at least minimize the negative consequences of radiation exposure. The present study aimed to assess the radioprotective potential of Helianthus tuberosus L. polysaccharide (HTLP) in vitality and micronuclei tests. To assess the cytotoxic effects of HTLP, both vitality and MTT reductase assays were conducted.

MATERIALS AND METHODS

RAW 264.7 cells viability was assessed 24 h after adding 200 μg/ml HTLP solution by staining cell cultures with propidium iodide and bis-benzimide to detect the nuclei of dead cells and the total number of cells in culture. To assess cell viability via cellular metabolic activity MTT test was used. In this work outbred 24-30 g 5-months old SHK mice have been used. Irradiation was provided with proton beams with an energy of 660 MeV at a dose rate of 80 Gy with doses 1.5 Gy for micronuclei test and 8.5 Gy for survival test. Whole body X-ray irradiation was conducted using the RUT-15 therapeutic X-ray unit with doses of 1.5 Gy for MN test and 6.5 Gy for survival. The HTLP sterile solution in dose 100 μg/animal was injected into the tail vein 15 min before X-ray or proton irradiation.

RESULTS AND CONCLUSION

s: Vitality test showed no significant differences between the control group and cells treated with 200 μl of 200 μg/ml HTLP solution, though a greater variability was noted. In contrast, the MTT assay indicated enhanced cell viability in the HTLP-treated cells. HTLP does not exert any toxic effects in cell culture. Moreover, results of MTT reductase assay shows, that HTLP may enhance the cells' metabolic activity. Animals pre-treated with HTLP displayed a significant reduction in micronuclei formation, showing five times fewer micronuclei in bone marrow cells compared to the non-treated group. This comparison highlights HTLP's potential protective effect against radiation-induced chromosomal damage. HTLP treatment demonstrates a significant reduction in hazard compared to the control, indicating its protective effects against irradiation. Thus, it can be concluded that the use of HTLP increases the likelihood of animal survival under the ionizing effects of X-rays and protons. The survival analysis reveals that the HTLP-treated groups exhibit a higher survival rate compared to both the control and Cysteamine-treated groups, suggesting a significant protective effect of HTLP against irradiation, regardless of the type of irradiation (proton or X-ray) with p < 0.0001.

Evaluation of the Polysaccharide "Immeran" Activity in Syrian hamsters' Model of SARS-CoV-2

COVID-19 is a highly contagious respiratory disease with a high number of lethal cases in humans, which causes the need to search for new therapeutic agents. Polysaccharides could be one of the prospective types of molecules with a large variety of biological activities, especially antiviral. The aim of this work was to study the specific antiviral activity of the drug "Immeran" on a model of a new coronavirus infection SARS-CoV-2 in hamsters. Based on the second experiment, intraperitoneal treatment with the drug according to a treatment regimen in doses of 500 and 1000 μg/kg (administration after an hour, then once a day every other day, a total of 3 administrations) was effective, reliably suppressing the replication of the virus in the lungs and, at a dose of 1000 μg/kg, prevented weight loss in animals. In all cases, the treatment stimulated the formation of virus-neutralizing antibodies to the SARS-CoV-2 virus, which suggests that the drug possesses adjuvant properties.

VII Congress of Russian Biophysicists-2023, Krasnodar, Russia

This special issue of Biophysical Reviews contains the materials presented at the VII Congress of Biophysicists of Russia, held from 17 to 23 April in Krasnodar. We believe that we have managed to prepare a selection of articles that well reflects the current state of biophysical science in Russia and its place in the world science. The VII Russian Congress on Biophysics was held in Krasnodar in April 2023, continuing the tradition of the series of biophysics conferences held every 4 years. The congress discussed physical principles and mechanisms of biological processes occurring at different life levels-from molecular to cellular and population levels. The results of fundamental and applied research in molecular biophysics, cell biophysics, and biophysics of complex systems were presented at plenary, sectional, and poster sessions. The works in the field of medical biophysics and neurobiology were especially widely presented. The structure and dynamics of biopolymers and fundamental mechanisms underlying the effects of physicochemical factors on biological systems, membrane, and transport processes were actively discussed. Much attention was paid to new experimental methods of biophysical research, methods of bioinformatics, computer, and mathematical modeling as necessary tools of the research at all levels of living systems. Along with fundamental problems of studying biophysical mechanisms of regulation of processes at the molecular, subcellular, and cellular levels, much attention was paid to applied research in the field of biotechnology and environmental monitoring. The Congress has formed the National Committee of Russian biophysicists.