Polygonatum sibiricum polysaccharide potentially attenuates diabetic retinal injury in a diabetic rat model

Polygonatum sibiricum (Huang Jing) polysaccharide reduces diabetic cardiomyopathy through increasing cyclic guanosine monophosphate-protein kinase G signaling in diabetic mice

AIMS/INTRODUCTION

Diabetic cardiomyopathy (DCM) is a prevalent condition among individuals with diabetes, and is associated with a high mortality rate. The anti-oxidant properties of Jing Huang or Polygonatum sibiricum polysaccharide (PSP) have been extensively used to treat diabetes-related disorders; however, its potential effectiveness against DCM remains unknown. This study aimed to investigate PSP's therapeutic effects on DCM in an experimental diabetic mouse model.

MATERIALS AND METHODS

To induce insulin resistance, mice were fed a high-fat diet for 3 months, followed by intraperitoneal streptozotocin injection to induce slight hyperglycemia and develop DCM. Both DCM and control mice were given PSP orally for 3 weeks. Western blotting was used to detect the protein expressions of protein kinase G, C/EBP homologous protein, glucose-regulated protein 78, phosphodiesterase type 5, protein kinase R-like endoplasmic reticulum (ER) kinase, and phospho-protein kinase R-like endoplasmic reticulum kinase in heart tissue.

RESULTS

The results showed a reduction in bodyweight and blood glucose levels in the PSP therapy group compared with DCM group. PSP also improved cardiac function and had a negligible effect on malondialdehyde activity. Furthermore, the findings showed that PSP alleviated ER and oxidative stress observed in DCM mice hearts, leading to the inhibition of cyclic guanosine monophosphate-specific phosphodiesterase type 5 and cardiac cyclic guanosine monophosphate reactivation. Phosphodiesterase type 5 inhibition reduced high-fat diet-induced cardiac dysfunction and decreased ER stress.

CONCLUSIONS

PSP could effectively protect diabetic myocardium by inhibiting endoplasmic reticulum stress. These findings provide crucial insights into the potential of PSP to ameliorate DCM conditions in diabetic mice by decreasing ER and oxidative stress, and enhancing cyclic guanosine monophosphate protein kinase G signaling.

A review on revolutionizing ophthalmic therapy: Unveiling the potential of chitosan, hyaluronic acid, cellulose, cyclodextrin, and poloxamer in eye disease treatments

Ocular disorders, encompassing both common ailments like dry eye syndrome and more severe situations for instance age-related macular degeneration, present significant challenges to effective treatment due to the intricate architecture and physiological barriers of the eye. Polysaccharides are emerging as potential solutions for drug delivery to the eyes due to their compatibility with living organisms, natural biodegradability, and adhesive properties. In this review, we explore not only the recent advancements in polysaccharide-based technologies and their transformative potential in treating ocular illnesses, offering renewed optimism for both patients and professionals but also anatomy of the eye and the significant obstacles hindering drug transportation, followed by an investigation into various drug administration methods and their ability to overcome ocular-specific challenges. Our focus lies on biological adhesive polymers, including chitosan, hyaluronic acid, cellulose, cyclodextrin, and poloxamer, known for their adhesive characteristics enhancing drug retention on ocular surfaces and increasing bioavailability. A detailed analysis of material designs used in ophthalmic formulations, such as gels, lenses, eye drops, nanofibers, microneedles, microspheres, and nanoparticles, their advantages and limitations, the potential of formulations in improving therapeutic outcomes for various eye conditions. Moreover, we underscore the discovery of novel polysaccharides and their potential uses in ocular drug delivery.

Research progress on medicinal components and pharmacological activities of polygonatum sibiricum

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonatum sibiricum, commonly known as Siberian Solomon's seal, is a traditional herb widely used in various traditional medical systems, especially in East Asia. In ancient China, the use of polygonatum sibiricum in medicine and food was mentioned in Li Shizhen's Bencao Gangmu of traditional Chinese medicine (TCM). It was also used in history of India in Vedic medicine. The plant is rich in bioactive substances such as polysaccharides, saponins, flavonoid and alkaloids.

AIM OF THE REVIEW

The aim of this review is to understand the pharmacological and pharmacokinetics research progress of the major components of polygonatum sibiricum, and to prospect its potential application and development in the treatment of various diseases.

MATERIALS AND METHODS

We conducted a systematic literature search against major online databases on the Web, including PubMed, ancient books, patents, PubMed, Wiley, Google Scholar, Web of Science, and others. We select the pharmacological process and mechanism of the main components of polygonatum sibiricum in a variety of diseases, and make a strict but careful supplement and in-depth elaboration to this review.

RESULTS

Several studies have demonstrated the strong antioxidant properties of polygonatum extract, which can be attributed to the presence of flavonoids and other polyphenol compounds; for diabetes and other metabolic-related diseases, polygonatum saponins have particular advantages in regulating intestinal flora and lipoprotein concentration in organisms. In addition, the polysaccharides extracted from this plant have a strong anti-inflammatory effect, which is related to its ability to regulate proinflammatory cytokine and mediators. In the aspect of anti-tumor effect, polygonatum derivatives can induce cancer cell apoptosis mainly by adjusting the cell membrane potential and cell cycle. It is worth noting that the combined action of the main components of polygonatum also offers promising solutions for the treatment of the disease.

CONCLUSION

Polygonatum polysaccharide has therapeutic effects on many diseases by adjusting cell signal pathways, polygonatum sibiricum have significant advantages in regulating intestinal flora, inducing apoptosis of tumor cells, activating antioxidant processes, etc. Further research and basic exploration are needed to prove the function and mechanisms of the main components of polygonatum sibiricum on related diseases. The study on the immunomodulatory properties of polygonatum revealed its potentiality of enhancing immune function, which made it an interesting subject for further exploration in the field of immunotherapy.

Chemokines in diabetic eye disease

BACKGROUND

Diabetic eye disease is a common micro-vascular complication of diabetes and a leading cause of decreased vision and blindness in people of working age worldwide.Although previous studies have shown that chemokines system may be a player in pathogenesis of diabetic eye disease, it is unclear which chemokines play the most important role.To date, there is no meta-analysis which has investigated the role of chemokines in diabetic eye disease.We hope this study will contribute to a better understanding of both the signaling pathways of the chemokines in the pathophysiological process, and more reliable therapeutic targets for diabetic eye disease.

METHODS

Embase, PubMed, Web of Science and Cochrane Library systematically searched for relevant studies from inception to Sep 1, 2023. A random-effect model was used and standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated to summarize the associated measure between chemokines concentrations and diabetic eye disease. Network meta-analysis to rank chemokines-effect values according to ranked probabilities.

RESULTS

A total of 33 different chemokines involving 11,465 subjects (6559 cases and 4906 controls) were included in the meta-analysis. Results of the meta-analysis showed that concentrations of CC and CXC chemokines in the diabetic eye disease patients were significantly higher than those in the controls. Moreover, network meta-analysis showed that the effect of CCL8, CCL2, CXCL8 and CXCL10 were ranked highest in terms of probabilities. Concentrations of CCL8, CCL2, CXCL8 and CXCL10 may be associated with diabetic eye disease, especially in diabetic retinopathy and diabetic macular edema.

CONCLUSION

Our study suggests that CCL2 and CXCL8 may play key roles in pathogenesis of diabetic eye disease. Future research should explore putative mechanisms underlying these links, with the commitment to develop novel prophylactic and therapeutic for diabetic eye disease.

Enhanced hypoglycemic effects of konjac glucomannan combined with Polygonatum cyrtonema Hua polysaccharide in complete nutritional liquid diet fed type 2 diabetes mice

In our aging society, dysphagia and malnutrition are growing concerns, necessitating intervention. Liquid nutrition support offers a practical solution for traditional dietary issues, but it raises a key issue: the potential for post-meal glucose spikes impacting efficacy. This study examined the effects of supplementation of Polygonatum cyrtonema Hua polysaccharide (PCP), konjac glucomannan (KGM) and their combination on acute phase postprandial glycemic response and long-term glucose metabolism in T2DM mice on a complete nutritional liquid diet. KGM was more effective in reducing postprandial glucose response, while PCP was more prominent in ameliorating long-term glucose metabolism. The KGM-PCP combination demonstrated superior outcomes in fasting blood glucose, insulin, and glucose homeostasis. PCP and KGM also influenced the composition and abundance of the gut microbiome, with the H-PCP group showing optimal performance. Moreover, the KGM-PCP combination improved body weight, lipid homeostasis, and liver health the most. PCP potentially regulates glycemia through metabolic pathways, while KGM improves glycemic metabolism by reducing postprandial glucose levels in response to viscous intestinal contents. This research identifies the structure, viscosity properties, and hypoglycemic effects of KGM and PCP in complete nutritional liquid diet fed T2DM mice, enabling their strategic utilization as hypoglycemic components in nutritional administration and glycemic regulation.

Nourishing Yin traditional Chinese medicine: potential role in the prevention and treatment of type 2 diabetes

Type 2 diabetes mellitus (T2DM), a common and frequently occurring disease in contemporary society, has become a global health threat. However, current mainstream methods of prevention and treatment, mainly including oral hypoglycemic drugs and insulin injections, do not fundamentally block the progression of T2DM. Therefore, it is imperative to find new ways to prevent and treat diabetes. Traditional Chinese medicine is characterized by multiple components, pathways, and targets with mild and long-lasting effects. Pharmacological studies have shown that nourishing yin traditional Chinese medicine (NYTCM) can play a positive role in the treatment of T2DM by regulating pathways such as the phosphatidylinositol 3-kinase/serine-threonine kinase, mitogen-activated protein kinase, nuclear factor-kappa B, and other pathways to stimulate insulin secretion, protect and repair pancreatic β cells, alleviate insulin resistance, ameliorate disordered glucose and lipid metabolism, mitigate oxidative stress, inhibit inflammatory responses, and regulate the intestinal flora. The pharmacologic activity, mechanisms, safety, and toxicity of NYTCM in the treatment of T2DM are also reviewed in this manuscript.

Protective effects and mechanisms of Momordica charantia polysaccharide on early-stage diabetic retinopathy in type 1 diabetes

Momordica charantia polysaccharide (MCP) is a potential drug for the prevention and alleviation of diabetes mellitus (DM) and diabetic retinopathy (DR). This study aimed to investigate the potential protective effects of MCP on early-stage DR and explore the underlying mechanisms. The model group (DM group) and treatment group (D+H group) were established by inducing type 1 DM using a single dose of streptozotocin (STZ) at 60 mg/kg. After modeling, the D+H group was orally administered a 500 mg/kg dose of MCP solution once daily for 12 weeks. Monitoring of systemic indicators (FBG, body weight, general condition) and retinal tissue inflammation and apoptosis (HE staining, IL-6, MCP-1, TNF-α, VEGF, NF-κB, Caspase-3) in this study demonstrated that MCP intervention alleviated both DM and DR. MCP improved the body weight and general condition of DM rats by reducing FBG levels. It also enhanced the anti-inflammatory and anti-apoptotic capabilities of retinal neurons and microvessels by modulating the actions of cytokines, thereby further regulating the inflammation and apoptosis of retinal neurons and microvessels. The underlying mechanisms may be associated with the downregulation of NF-κB and Caspase-3 pathway protein expression, as well as the downregulation of mRNA expression of NF-κB and Caspase-3 pathway genes. Further research is needed to elucidate the potential mechanisms underlying the protective effects of MCP on DR. MCP may emerge as a selective medication for the prevention and alleviation of DM and a novel natural medicine for the prevention and alleviation of DR.

Methyl protodioscin reduces c-Myc to ameliorate diabetes mellitus erectile dysfunction via downregulation of AKAP12

BACKGROUND

Diabetes mellitus erectile dysfunction (DMED) is one of common complications of diabetes. We aimed to investigate the potential efficacy of methyl protodioscin (MPD) in DMED and explored the underlying mechanism.

METHODS

Diabetic mice were induced by streptozotocin, while vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) were stimulated with high glucose. MPD was administrated in vitro and in vivo to verify its efficacy on DMED. The interaction of c-Myc and AKAP12 was determined by luciferase reporter assay and chromatin immunoprecipitation assay.

RESULTS

c-Myc and AKAP12 were upregulated in penile tissues in DMED mice. In high glucose-stimulated VSMCs or VECs, MPD intervention enhanced cell viability, inhibited apoptosis, decreased c-Myc and AKAP12, as well as elevated p-eNOS Ser1177. MPD-induced apoptosis inhibition, AKAP12 reduction and p-eNOSSer1177 elevation were reversed by AKAP12 overexpression. c-Myc functioned as a positive regulator of AKAP12. Overexpression of c-Myc reversed the effects induced by MPD in vitro, which was neutralized by AKAP12 silencing. MPD ameliorated erectile function in diabetic mice via inhibiting AKAP12.

CONCLUSIONS

MPD improved erectile dysfunction in streptozotocin-caused diabetic mice by regulating c-Myc/AKAP12 pathway, indicating that MPD could be developed as a promising natural agent for the treatment of DMED.

Research progress on the hypoglycemic activity and mechanisms of natural polysaccharides

The incidence of diabetes, as a metabolic disease characterized by high blood sugar levels, is increasing every year. The predominantly western medicine treatment is associated with certain side effects, which has prompted people to turn their attention to natural active substances. Natural polysaccharide is a safe and low-toxic natural substance with various biological activities. Hypoglycemic activity is one of the important biological activities of natural polysaccharides, which has great potential for development. A systematic review of the latest research progress and possible molecular mechanisms of hypoglycemic activity of natural polysaccharides is of great significance for better understanding them. In this review, we systematically reviewed the relationship between the hypoglycemic activity of polysaccharides and their structure in terms of molecular weight, monosaccharide composition, and glycosidic bonds, and summarized underlying molecular mechanisms the hypoglycemic activity of natural polysaccharides. In addition, the potential mechanisms of natural polysaccharides improving the complications of diabetes were analyzed and discussed. This paper provides some valuable insights and important guidance for further research on the hypoglycemic mechanisms of natural polysaccharides.

Research on the Impact of Deep Eutectic Solvent and Hot-Water Extraction Methods on the Structure of Polygonatum sibiricum Polysaccharides

Deep eutectic solvent (DES) and hot-water extraction (HWE) methods were utilized to extract polysaccharides from Polygonatum sibiricum, referred to as DPsP and WPsP, respectively. The extracted polysaccharides were purified using the Superdex-200 dextran gel purification system, resulting in three components for each type of polysaccharide. The structures of these components were characterized. The molecular weight analysis revealed that DPsP components had slightly larger molecular weights compared with WPsP, with DPsP-A showing a slightly higher dispersity index and broader molecular weight distribution. The main monosaccharide components of both DPsP and WPsP were mannose and glucose, while DPsP exhibited a slightly greater variety of sugar components compared with WPsP. FTIR analysis demonstrated characteristic polysaccharide absorption peaks in all six PSP components, with a predominance of acidic pyranose sugars. NMR analysis revealed the presence of pyranose sugars, including rhamnose and sugar aldehyde acids, in both DPsP-B and WPsP-A. DPsP-B primarily exhibited β-type glycosidic linkages, while WPsP-A predominantly displayed α-type glycosidic linkages, with a smaller fraction being β-type. These findings indicated differences in monosaccharide composition and structure between PSPs extracted using different methods. Overall, this study provided experimental evidence for future research on the structure-function relationship of PSPs.

Polygonati Rhizoma with the homology of medicine and food: A review of ethnopharmacology, botany, phytochemistry, pharmacology and applications

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonati Rhizoma (PR), which contains rich national cultural connotations, is a traditional Chinese medicine with homology of medicine and food. It has been used for a long time as a tonic in China's multi-ethnic medical system, and is also used to treat diseases such as premature graying hair, deficiency of blood and essence, diabetes, hypertension, etc. Meanwhile, PR is often used as food in China, India, South Korea and other Asian countries, which can satisfy hunger and provide many health benefits.

AIM OF THE REVIEW

This paper systematically reviewed the ethnopharmacology, botany, phytochemistry, pharmacology and related applications research of PR, and provided a reference for the comprehensive applications of PR, including basic research, product development and clinical applications. This paper also refined the national application characteristics of PR, such as rich plant resources, special chemical components and anti-hidden hungry, which laid a foundation for its high value and high connotation development in the future.

MATERIALS AND METHODS

The literature information was collected systematically from the electronic scientific databases, including PubMed, Science Direct, Google Scholar, Web of Science, Geen Medical, China National Knowledge Infrastructure, as well as other literature sources, such as classic books of herbal medicine.

RESULTS

A comprehensive analysis of the above literature confirmed that PR has been used in the ethnic medicine system of Asian countries such as China for thousands of years. In this paper, 12 species including official species that can be used as PR are summarized, which provide rich plant resources for PR. The chemical components in PR are divided into nutritional components and active components. The former not only contains non-starch polysaccharides and fructo-oligosaccharides, which account for about 50% in PR and are recognized as high-quality diet in the world, but also contains inorganic elements and mineral elements. And a total of 199 kinds active ingredients, including saponins, flavonoids, alkaloids, etc., were sorted out by us. The above ingredients make PR have a special property of anti-hidden hunger. Studies have shown that PR has a wide range of pharmacological activities, such as immune regulation, blood glucose regulation, lipid-lowering, antioxidant, anti-tumor, antibacterial, etc. It has been widely used in medicine, food, cosmetics, gardens and other fields.

CONCLUSIONS

PR, as a classic medicinal material of the same origin, is widely used in the traditional ethnic medicine system. It contains abundant potential plant resources, chemical components and pharmacological activities. This paper also suggests that PR with high application value in food industry, has the potential to become a high-quality coarse grain. Exploring the way of grain and industrialization of PR is beneficial to fully develop the economic value of PR.

Bioactive compounds from Polygonatum genus as anti-diabetic agents with future perspectives

Diabetes mellitus (DM) is one of the most serious health problems worldwide. Species in the genus Polygonatum are traditional food and medicinal plants, which play an important role in controlling blood glucose. In this reveiw, we systematically summarized the traditional and modern applications of the genus Polygonatum in DM, focused on the material bases of polysaccharides, flavonoids and saponins. We highlighted their mechanisms of action in preventing obese diabetes, improving insulin resistance, promoting insulin secretion, regulating intestinal microecology, inhibiting advanced glycation end products (AGEs) accumulation, suppressing carbohydrate digestion and obsorption and modulating gluconeogenesis. Based on the safety and efficacy of this 'medicinal food' and its utility in the prevention and treatment of diabetes, we proposed a research and development program that includs diet design (supplementary food), medical nutrition therapy and new drugs, which could provide new pathways for the use of natural plants in prevention and treatment of DM.

Review on the genus Polygonatum polysaccharides: Extraction, purification, structural characteristics and bioactivities

The genus Polygonatum is gaining increasing attention from nutrition experts as well as health-conscious consumers because of its excellent performance in providing nutrients. Among these plants, Polygonatum sibiricum and Polygonatum odoratum have been selected for inclusion in China's Medicinal Food Directory due to their high safety profile. Polysaccharides are considered the main functional component and one of the main active ingredients of the plant. In addition, polysaccharides from genus Polygonatum have a variety of nutritional, biological and health-promoting properties, such as immunomodulatory, anti-inflammatory, cardiovascular protective, neuroprotective, antitumor, antidiabetic, antiosteoporosis, and hepatoprotective properties. This paper reviews the origin, extraction, purification, structural characteristics, biological activity, safety, toxicological evaluation, and structure-activity relationship of polysaccharides from the genus Polygonatum. Ultimately, we hope that this work can provide a more useful reference for understanding the polysaccharide structure and developing of new functional foods from polysaccharides of the genus Polygonatum.

Advances in Polygonatum sibiricum polysaccharides: Extraction, purification, structure, biosynthesis, and bioactivity

Polygonatum sibiricum has been used as food and medicine for thousands of years, and P. sibiricum polysaccharides (PSPs) have become the hot research spot due to their various health-promoting functions. Numerous studies have shown that PSPs possess huge potential in the application of functional food and medicine fields. However, the research status and features of the preparation process, molecular structure, and bioactivities of PSPs are unclear. Therefore, this review makes a comprehensive summary and proposes new insights and guidelines for the extraction, purification, structural features, biosynthesis, and multiple bioactivities of PSPs. Notably, it is concluded that PSPs mainly contain several types of polysaccharides, including fructan, pectin, galactomannan, glucomannans, arabinogalactan, and galactan, and multiple bioactivates, including osteogenic activity, anti-obesity, anti-diabetes, anti-depression, antioxidant, antiglycation, and protective effect against neurotoxicity and gut microbiota regulating activity. This review contributes to the structure-function study and resource utilization of P. sibiricum and its polysaccharides in food fields.

Polygonatum sibiricum ameliorated cognitive impairment of naturally aging rats through BDNF-TrkB signaling pathway

Cognitive dysfunction is high in the elderly population and seriously affects the quality of life. Brain-derived neurotrophic factor (BDNF) is one of the key neurotrophic proteins, and activation of BDNF-TrkB is considered an effective strategy to improve cognitive dysfunction during aging. In this study, administration of polygonatum sibiricum (PS) for 5 months effectively ameliorates the cognitive function, improving the Nissl body state in cortex and hippocampus in aging rats. In addition, PS can improve the synaptic structure and increase the number of synapses. Furthermore, PS reverses the reduction of synaptic plasticity-related proteins postsynaptic density protein 95 (PSD-95) and synaptophysin during aging and up-regulates the expression of BDNF-TrkB. In conclusion, PS improves cognitive dysfunction and enhances synaptic plasticity in naturally aged rats by regulating the BDNF-TrkB signaling pathway. PS has the potential to be developed as a novel and promising functional health food for the elderly. PRACTICAL APPLICATIONS: Polygonatum sibiricum (PS) is a traditional Chinese medicine, which has been included in the homologous plant of medicine and food. PS has been widely used to treat lung diseases, diabetes and antiaging in clinical. Studies have confirmed that PS can accelerate the repair and regeneration of damaged neurons, reverse the changes in synaptic structure, and improve the ability of learning and memory. Our study confirmed that PS significantly improved the cognitive function in aging rats. PS has great potential to be developed as a functional food for improving neurological function and anti-aging.

Effects of steam on polysaccharides from Polygonatum cyrtonema based on saccharide mapping analysis and pharmacological activity assays

Background

Polygonatum cyrtonema, one of origins of Polygonata Rhizoma (HuangJing in Chinese), is traditionally steamed repeatedly before being used as herbal medicine in China. However, there has no standard for steaming of HuangJing. Therefore, a comprehensive study for effects of steam on polysaccharides from Polygonatum cyrtonema based on saccharide mapping, a powerful method developed for polysaccharides analysis, and pharmacological activity are still necessary, which is helpful to explore the effect of steam on the physiochemical and biological activities of its polysaccharides and develop steaming standard of Polygonatum cyrtonema.

Methods

To explore the effect of steam on physiochemical and biological activities of P. cyrtonema polysaccharides (PCP), six polysaccharides named PCP0, PCP1, PCP2, PCP3, PCP4 and PCP5 were extracted from the herb consecutively steamed for 0–5 times, respectively. Their molecular weight distribution, monosaccharide composition and PACE fingerprints were investigated through HPSEC-MALLS-RID, HPAEC-PAD and saccharide mapping based on polysaccharides analysis by using carbohydrate gel electrophoresis (PACE) and HPTLC, respectively. In addition, their antioxidant ability and immunostimulatory activities on RAW 264.7 cells in terms of NO production and phagocytosis were compared.

Results

Results suggested that molecular weights could be changed during steam, which increased by first steaming and then decreased with further steaming though all polysaccharides’ molecular weights were 10⁵-10⁷ Da. They all showed irregularly spherical conformation in aqueous solution based on AFM imaging. Their monosaccharide composition and PACE fingerprints were significantly different after steaming, i.e., galactose increased while glucose and mannose decreased, and β-1,4-Galp appeared while β-1,4-Manp increased, after steaming. Steamed PCP significantly increased scavenging activity against ABTS radicals, while PCP0 had the best immunostimulatory effect on RAW 264.7 in terms of NO production and phagocytosis.

Conclusions

In summary, steam significantly affected the chemical composition and bioactivities of polysaccharides from P. cyrtonema. Considering the balance beneficial effects of steaming on antioxidant and immunopotentiation activities of PCP, 2 times of continuous steam is the optimal choice under the given conditions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-022-00650-3.

Blood-Enriching Effects and Immune-Regulation Mechanism of Steam-Processed Polygonatum Sibiricum Polysaccharide in Blood Deficiency Syndrome Mice

Polygonatum sibiricum Red. has been used as a medicinal herb and nutritional food in traditional Chinese medicine for a long time. It must be processed prior to clinical use for safe and effective applications. However, the present studies mainly focused on crude Polygonatum sibiricum (PS). This study aimed to investigate the chemical properties, blood-enriching effects and mechanism of polysaccharide from the steam-processed Polygonatum sibiricum (SPS), which is a common form of PS in clinical applications. Instrumentation analyses and chemistry analyses revealed the structure of SPS polysaccharide (SPSP). A mice model of blood deficiency syndrome (BDS) was induced by acetylphenylhydrazine (APH) and cyclophosphamide (CTX). Blood routine test, spleen histopathological changes, serum cytokines, etc. were measured. The spleen transcriptome changes of BDS mice were detected by RNA sequencing (RNA-seq). The results showed that SPSP consists predominantly of Gal and GalA together with fewer amounts of Man, Glc, Ara, Rha and GlcN. It could significantly increase peripheral blood cells, restore the splenic trabecular structure, and reverse hematopoietic cytokines to normal levels. RNA-seq analysis showed that 122 differentially expressed genes (DEGs) were obtained after SPSP treatment. GO and KEGG analysis revealed that SPSP-regulated DEGs were mainly involved in hematopoiesis, immune regulation signaling pathways. The reliability of transcriptome profiling was validated by quantitative real-time PCR and Western blot, and the results indicated that the potential molecular mechanisms of the blood-enriching effects of SPSP might be associated with the regulating of JAK1-STAT1 pathway, and elevated the hematopoietic cytokines (EPO, G-CSF, TNF-α and IL-6). This work provides important information on the potential mechanisms of SPSP against BDS.

Advances in Mechanism Research on Polygonatum in Prevention and Treatment of Diabetes

Diabetes mellitus is a fast-growing disease with a major influence on people’s quality of life. Oral hypoglycemic drugs and insulin are currently the main effective drugs in the treatment of diabetes, but chronic consumption of these drugs has certain side effects. Polysaccharides, saponins, flavonoids, and phenolics are the primary secondary metabolites isolated from the rhizomes of Polygonatum sibiricum Redouté [Asparagaceae], Polygonatum kingianum Collett & Hemsl [Asparagaceae], or Polygonatum cyrtonema Hua [Asparagaceae], which have attracted much more attention owing to their unique therapeutic role in the treatment and prevention of diabetes. However, the research on the mechanism of these three Polygonatum spp. in diabetes has not been reviewed. This review provides a summary of the research progress of three Polygonatum spp. on diabetes and its complications, reveals the potential antidiabetic mechanism of three Polygonatum spp., and discusses the effect of different processed products of three Polygonatum spp. in treating diabetes, for the sake of a thorough understanding of its effects on the prevention and treatment of diabetes and diabetes complications.

Recent advances in polysaccharides from edible and medicinal Polygonati rhizoma: From bench to market

Although the increasing studies have corroborated the biological activities and great market utilization value of polysaccharide fractions derived from Polygonati rhizome, a well-known edible and medicinal plant, Polygonati rhizome polysaccharides (PRPs) still lack sufficient attention. Herein, we make attempt to systematically summarize recent advances in the extraction, purification, structural characteristics, biological activities, and commercial products of PRPs. Based on the detailed extraction and structural characteristics, the biological activities of PRPs including immune-regulation, anti-osteoporosis, anti-Alzheimer's disease, anti-diabetes and anti-atherosclerotic, are emphatically summarized, as well as the possible related mechanisms. Most importantly, about 365 kinds of commercial functional foods and over 500 patents related to PRPs as the main raw material were analyzed to explore the status quo and bottleneck for the development and utilization of PRPs. In conclusion, this review will benefit to bridge the gap between basic knowledge and market innovations, and facilitate the in-depth utilization of PRPs.

Study on the Chemical Changes of the Traditional Process from Polygonatum kingianum by Multiple Fingerprint Profiles Combined with Multivariate Methods

Polygonati Rhizoma (Huangjing) is traditional medicine in China, which can only be used as medicine after being processed. However, there is a limited theoretical basis for analyzing the change of chemical components in traditional processing. In the present study, the analytical techniques including Fourier transform infrared spectroscopy, high-performance gel permeation chromatography-evaporative light scattering detector, and high-performance liquid chromatography-diode array detector were proposed to perform multiple fingerprint analyses of the changes of the processed materials; the total sugar was also determined. Moreover, the chemometric studies, including hierarchical cluster analysis and principal component analysis, were used to visualize the discrimination of raw and processed materials. The results revealed that the chemical constituents had been profoundly changed after the process. In conclusion, these methods could be successfully used to compare raw and processed materials of P. kingianum, which could be used to elaborate the rationality of processing from the perspective of chemical composition.

Evolutionary research trend of Polygonatum species: a comprehensive account of their transformation from traditional medicines to functional foods

With the advances in Polygonatum research, there is a huge interest in harnessing the valuable functional ingredients of this genus with the potential for functional foods. This review emphasizes the different aspects of Ploygonatum based research starting from its bioactive compounds, their structural characterization, various extraction methods, as well as biological activities. In view of its integral use as an essential medicinal plant, our review emphasizes on its promising food applications both as an ingredient and as a whole food, and its improved health benefits with potential for agricultural and environmental relevance are also discussed. As we collated the recent research information, we present the main challenges and limitations of the current research trend in this area which can upgrade the further expansion of Polygonatum-related research that will strengthen its economic and accessible nutritional value in the food and health industries. By highlighting the need for the unattended species, this review not only fills existing research gaps, but also encourages the researchers to find new avenues for the natural production of bio-based functional materials and the development of highly functional and health-promoting foods for disease prevention and treatment.

Polygonatum sibiricum F. Delaroche polysaccharide ameliorates HFD‑induced mouse obesity via regulation of lipid metabolism and inflammatory response

The present study sought to elucidate the role of Polygonatum sibiricum F. Delaroche polysaccharide (PSP) in high‑fat diet (HFD)‑induced mouse obesity and investigated the primary molecular mechanism underlaying these effects. An obese mouse model was established by feeding HFD and three doses of PSP were administered intragastrically. Changes in body weight, serum lipids and parameters were recorded and the mechanism was explored by reverse transcription‑quantitative PCR and western blotting. Body weight, blood lipids, blood glucose, insulin, resistin, adiponectin, liver weight and abdominal fat pads weight were reduced by PSP and abnormal expression levels of inflammatory factors such as TNF‑α, IL‑6, IL‑1β and iNOS and lipid metabolism genes such as FAS, SREBP‑1, PPARα and CPT‑1were also reversed by PSP. The 5' adenosine monophosphate‑activated protein kinase (AMPK) signaling pathway was activated in PSP mouse liver, leading to lipid‑lowering and anti‑inflammatory effects. The results therefore suggested that PSP exhibited lipid‑lowering and anti‑inflammatory effects by activating the AMPK signaling pathway.

Huangyusang decoction for Type 2 diabetes: A protocol for systematic review and meta analysis

BACKGROUND

Diabetes is a chronic metabolic disease characterized by elevated blood glucose levels due to insulin resistance and β-cell dysfunction. In China, Huangyusang decoction (HYS) has been widely used to treat Type 2 diabetes. However, there is no systematic review found. In order to evaluate the efficacy and safety of HYS in the treatment of Type 2 diabetes, we need to conduct a meta-analysis and systematic evaluation.

METHODS

We will enroll the randomized controlled trials (RCTs) evaluating the effectiveness and safety of HYS in the treatment of Type 2 diabetes. Data come mainly from 4 Chinese databases (CNKI, Wanfang, CBM, and VIP Database) and 4 English databases (PubMed, Embase, Cochrane Library, and Web of science). The enrollment of RCTs is from the starting date of database establishment till January 30, 2021. Fasting blood glucose is considered as the main indicator of the dyslipidemia, while the body mass index, glycated hemoglobin, fasting insulin, triglycerides, and cholesterol are regarded as the secondary indicators. There are safety indicators including liver enzyme and kidney function. The work such as selection of literature, data collection, quality evaluation of included literature, and assessment of publication bias will be conducted by 2 independent researchers. Meta-analysis will be performed by RevMan 5.0 software.

RESULTS

This study will provide high-quality evidence for the effectiveness and safety of HYS in the treatment of type 2 diabetes.

CONCLUSION

The results of the study will help us determine whether HYS can effectively treat type 2 diabetes.

ETHICS AND DISSEMINATION

This study does not require ethical approval. We will disseminate our findings by publishing results in a peer-reviewed journal.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/AXBRV.

Polygonatum sibiricum polysaccharide inhibits high glucose-induced oxidative stress, inflammatory response, and apoptosis in RPE cells

Diabetic retinopathy is one of the major diabetic complications and remains the most common cause of adult blindness among patients with diabetes mellitus. Polygonatum sibiricum polysaccharides (PSP) are a group important component of Polygonatum sibiricum (PS) with anti-diabetic activity. However, the effect and underlying mechanism of PSP on diabetic retinopathy remains unclear. We used high glucose (HG)-stimulated ARPE-19 cells to establish in vitro diabetic retinopathy model. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay was performed to evaluate cell viability of ARPE-19 cells. The changes in the ROS production, malondialdehyde (MDA) content, and activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were detected to indicate oxidative stress. The secretion levels of tumor necrosis factor-alpha (TNF-α) and interleukin-8 (IL-8) were detected by ELISA. The protein levels of TNF-α, IL-8, bcl-2, bax, nuclear Nrf2, and anti-hemeoxygenase-1 (HO-1) were detected by western blot analysis. Our results showed that HG treatment caused a significant reduction in cell viability of ARPE-19 cells. PSP treatment improved the reduced cell viability of ARPE-19 cells. PSP also attenuated HG-induced oxidative stress with decreased ROS production and MDA content, as well as increased the activities of SOD and GPx. In addition, HG significantly increased bax expression and caspase-3 activity, and decreased bcl-2 expression. However, these changes were mitigated by PSP treatment. Furthermore, PSP markedly induced the activation of Nrf2/HO-1 pathway in HG-induced ARPE-19 cells. Knockdown of Nrf2 reversed the protective effects of PSP on HG-induced ARPE-19 cells. Taken together, these findings indicated that PSP protects ARPE-19 cells from HG-induced oxidative stress, inflammation, and cell apoptosis through regulation of Nrf2/HO-1 signaling pathway.

Polysaccharide-Based Nanomaterials for Ocular Drug Delivery: A Perspective

Ocular drug delivery is one of the most challenging issues in ophthalmology because of the complex physiological structure of the eye. Polysaccharide-based nanomaterials have been extensively investigated in recent years as ideal carriers for enhancing the bioavailability of drugs in the ocular system because of their biocompatibility and drug solubilization. From this perspective, we discuss the structural instability of polysaccharides and its impact on the synthesis process; examine the potential for developing bioactive polysaccharide-based ocular drug nanocarriers; propose four strategies for designing novel drug delivery nanomaterials; and suggest reviewing the behavior of nanomaterials in ocular tissues.

Structural characterization, hypoglycemic effects and antidiabetic mechanism of a novel polysaccharides from Polygonatum kingianum Coll. et Hemsl

The rhizome of Polygonatum kingianum has been used as a traditional medicine in China. In this study, a novel polysaccharides (PKPs-1) was isolated from P. kingianum and characterized by its molecular weight, primary structure. The hypoglycemic activity of PKPs-1was investigated by in vitro assay with the HepG2 cell line and in vivo test using STZ-induced diabetic mice. Results showed that the average molecular weight of PKPs-1 was 14.05 kDa and is composed mainly of glucose and mannose. Methylation analysis indicated that this polysaccharides fraction consisted mainly of β1,2-link glucose. Besides, PKPs-1 exhibited significant anti-hyperglycemic activity on STZ-induced mice, improved insulin tolerance, and affected the metabolism of serum lipids. Results of real-time quantitative PCR (RT-PCR) showed that PKPs-1 significantly increased the expression of insulin receptor substrate-1 (IRS-1), phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT), indicating that PKPs-1 regulates glucose metabolism by activating the PI3K/AKT signaling pathway. This study provides new insights for investigating the hypoglycemic effects of PKPs-1 and suggests that PKPs-1 could be a promising functional food or medicine for treating T2DM.

Hypoglycemic effects and modulation of gut microbiota of diabetic mice by saponin fromPolygonatum sibiricum

Polygonatum sibiricumis a medicinal and homologous plant grown in China. The saponin inPolygonatum sibiricumhas shown its good hypoglycemic performance, and it can be developed as functional foods and drugs with hypoglycemic effect.

Polygonatum sibiricum polysaccharide alleviates inflammatory cytokines and promotes glucose uptake in high‑glucose‑ and high‑insulin‑induced 3T3‑L1 adipocytes by promoting Nrf2 expression

Polygonatum sibiricum polysaccharide (PSP) has been shown to alleviate hyperglycemia and reduce oxidative stress to delay the progression of diabetic retinopathy and cataracts. However, its role and underlying mechanisms in regulating type 2 diabetes mellitus (T2DM) remain unclear. Nuclear factor erythroid 2‑related factor 2 (Nrf2) activation plays a protective role in T2DM. The present study focused on the effect of PSP on inflammatory cytokine secretion and Nrf2 expression in the adipocytes of T2DM patients. In this study, high‑glucose‑ and high‑insulin‑induced 3T3‑L1 adipocytes were used to mimic insulin‑resistant (IR)‑3T3‑L1 adipocytes. Furthermore, the effect and underlying mechanisms of PSP on inflammation and glucose uptake in IR‑3T3‑L1 adipocytes were investigated. The present study found that proliferation after 50, 100 and 250 µg/ml PSP treatment had no significant change in normal 3T3‑L1 adipocytes. A total of 50, 100 and 250 µg/ml of PSP also alleviated IL‑1β, IL‑6, and TNF‑α levels and promoted proliferation, glucose uptake, and glucose transporter 4 expression in IR‑3T3‑L1 adipocytes. Furthermore, 50, 100 and 250 µg/ml PSP promoted Nrf2 and HO‑1 expression. However, silencing Nrf2 expression reversed the effect of 100 µg/ml PSP in IR‑3T3‑L1 adipocytes. In conclusion, these results suggest that PSP alleviates inflammatory cytokines and promotes glucose uptake in IR‑3T3‑L1 adipocytes by promoting Nrf2 expression. PSP may be a potential therapeutic agent for T2DM treatment by promoting Nrf2 expression.