RAW264.7 Cell Activating Glucomannans Extracted from Rhizome of Polygonatum sibiricum

Polygonati Rhizoma: A review on the extraction, purification, structural characterization, biosynthesis of the main secondary metabolites and anti-aging effects

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonati Rhizome (PR) is a plant that is extensively widespread in the temperate zones of the Northern Hemisphere. It is a member of the Polygonatum family of Asparagaceae. PR exhibits diverse pharmacological effects and finds applications in ethnopharmacology, serving as a potent tonic for more than two millennia. PR's compounds endow it with various pharmacological properties, including anti-aging, antioxidant, anti-fatigue, anti-inflammatory, and sleep-enhancing effects, as well as therapeutic potential for osteoporosis and age-related diseases.

AIM OF THE STUDY

This review seeks to offer a thorough overview of the processing, purification, extraction, structural characterization, and biosynthesis pathways of PR. Furthermore, it delves into the anti-aging mechanism of PR, using organ protection as an entry point.

MATERIALS AND METHODS

Information on PR was obtained from scientific databases (Google Scholar, Web of Science, ScienceDirect, SciFinder, PubMed, CNKI) and books, doctoral theses, and master's dissertations.

RESULTS

In this investigation, 49 polysaccharides were extracted from PR, and the impact of various processing, extraction, and purification techniques on the structure and activity of these polysaccharides was evaluated. Additionally, 163 saponins and 46 flavonoids were identified, and three key biosynthesis pathways of secondary metabolites were outlined. Notably, PR and Polygonat Rhizomai polysaccharides (PRP) exhibit remarkable protective effects against age-induced injuries to the brain, liver, kidney, intestine, heart, and vessels, thereby promoting longevity and ameliorating the aging process.

CONCLUSIONS

PR, a culinary and therapeutic herb, is rich in active components and pharmacological activities. Based on this review, PR plays a meaningful role in lifespan extension and anti-aging, which can be attributed to PRP. Future research should delve deeper into the structural aspects of PRP that underlie its anti-aging effects and explore potential synergistic interactions with other compounds. Moreover, exploring the potential applications of PR in functional foods and pharmaceutical formulations is recommended to advance the development of industries and resources focused on healthy aging.

Review of studies on polysaccharides, lignins and small molecular compounds from three Polygonatum Mill. (Asparagaceae) spp. in crude and processed states

Since ancient times, Polygonatum Mill. (Asparagaceae) has been utilized as a medicinal and culinary resource in China. Its efficacy in treating various illnesses has been well documented. Traditional processing involves the Nine-Steam-Nine-Bask method, which results in a reduction of toxicity and enhanced effectiveness of Polygonatum. Many substances, such as polysaccharides, lignins, saponins, homoisoflavones, alkaloids, and others, have been successfully isolated from Polygonatum. This review presents the research progress on the chemical composition of three crude and processed Polygonatum, including Polygonatum sibiricum Redouté (P. sibiricum), Polygonatum kingianum Collett & Hemsl (P. kingianum), and Polygonatum cyrtonema Hua (P. cyrtonema). The review also includes the pharmacology of Polygonatum, specifically on the pharmacology of polysaccharides both before and after processing. Its objective is to provide a foundation for uncovering the significance of the processing procedure, and to facilitate the development and utilization of Polygonatum in clinical practice.

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.

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.

Health-Promoting Activities and Associated Mechanisms of Polygonati Rhizoma Polysaccharides

Polygonati Rhizoma, a typical homology of medicine and food, possesses remarkable anti-fatigue, anti-aging, metabolic regulatory, immunomodulatory, anti-inflammatory, neuroprotective, anti-diabetes, and anti-cancer effects. Among bioactive phytochemicals in Polygonati Rhizoma, polysaccharides play important roles in the health-promoting activities through the mechanisms mentioned above and potential synergistic effects with other bioactives. In this review, we briefly introduce the updated biosynthesis of polysaccharides, the purification method, the structure characterization, and food applications, and discuss in detail the biological activities of Polygonati Rhizoma polysaccharides and associated mechanisms, aiming at broadening the usage of Polygonati Rhizoma as functional food and medicine.

Polygonatum sibiricum Polysaccharide Inhibited Liver Cancer in a Simulated Tumor Microenvironment by Eliminating TLR4/STAT3 Pathway

Liver cancer is one of the most aggressive tumors and one of the most common malignant tumors which seriously threatens human health. Traditional Chinese medicine (TCM) was reported to resist the proliferation and metastasis of liver cancer cells. In this study, we aimed to explore the potential anti-cancer effect of Polygonatum sibiricum polysaccharide (PSP) on the tumor immune microenvironment in liver cancer cells. HepG2 and Hep3B cells were pretreated in the absence or the presence of PSP (20, 50, 100 µg/mL) for a period of 24 h. Subsequently, dendritic cells (DCs) were co-cultured with HepG2 and Hep3B cell supernatant to investigate the effect of PSP on the tumor microenvironment. The results showed that PSP dose-dependently inhibited proliferation and promoted apoptosis of HepG2 and Hep3B cells. Meanwhile, PSP dose-dependently inhibited migration, invasion, and epithelial-to-mesenchymal transition (EMT) of liver cancer cells. In addition, PSP dose-dependently induced inflammatory response of DCs, characterized by increases of interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α in DCs. Mechanically, PSP dose-dependently reduced the activation of the Toll-like receptor 4 (TLR4)/Signal transducer and activator of transcription 3 (STAT3) and noncanonical nuclear factor-kappa B (NF-κB) signaling pathways. TLR4 agonist lipopolysaccharide (LPS) reversed the anti-oncogenic effects of PSP in liver cancer cells. Taken together, PSP inhibited liver cancer in a simulated tumor microenvironment by eliminating TLR4/STAT3 pathway. PSP promises an important and useful alternative to liver cancer treatment.

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.

Benefits of neutral polysaccharide from rhizomes of Polygonatum sibiricum to intestinal function of aged mice

One purified neutral polysaccharide fraction was obtained from the rhizome of Polygonatum sibiricum by DEAE ion exchange and gel chromatography. Structure elucidation was performed by methanolysis, methylation, FT-IR, and NMR. The results indicated that PSP-NP was composed of 1,4-β-D-Gal,1, 4, 6-β-D-Gal, T-α-D-Man,1, 4-α-D-Glc, and T-α-D-Glc with a molecular weight of 43.0 kDa. We supplied this polysaccharide to aged mice and found it is of benefits to intestinal functions, as indicated by better tissue integrity and motility, improved oxidative stress and inflammation, reduced intestinal permeability and serum LPS level, as well as balanced gut microbial composition and short-chain fatty acids production. These results display a novel Polygonatum sibiricum polysaccharide to improve the intestinal function of aged mice, which provides pieces of evidence for its further development and utilization.

Research on Processing-Induced Chemical Variations in Polygonatum Cyrtonema Rhizome by Integrating Metabolomics and Glycomics

Polygonatum cyrtonema rhizome (PCR), the dried sweet rhizome of Polygonatum cyrtonema Hua, is commonly used as a tonic remedy and a functional food in Asia, Europe, and North America. Multiple components, including secondary metabolites, monosaccharides, oligosaccharides, and polysaccharides, collectively contribute to the therapeutic effects of PCR. Processing time exerts a significant influence on the quality of PCR, but the various processing stages have not been comprehensively chemically profiled. It is urgent to study processing-induced chemical variations in PCR to control the processing degree. In this study, multiple chromatographic and mass spectrometric techniques were used in combination with multivariate statistical analysis to perform qualitative and quantitative research on secondary metabolites and carbohydrates in PCR during processing. The results demonstrated that PCR processing can be divided into three stages, namely the raw stage (0 h), the middle stage (1–6 h), and the late stage (8–18 h). Twenty differential compounds were screened from secondary metabolites and oligosaccharides to distinguish PCR in different processing stages. Furthermore, the chemical variations of Polygonatum cyrtonema polysaccharides (PCP) also entered a new stage after processing for 6 h. Multiple chemical mechanisms, including hydrolysis, oxidative decomposition, dehydration, Maillard reaction, and polymerization were involved in the processing. This work provides a scientific basis to reveal the relationship between processing stage and chemical variations.

Potential Antioxidative and Anti-Hyperuricemic Components Targeting Superoxide Dismutase and Xanthine Oxidase Explored from Polygonatum Sibiricum Red

Polygonatum sibiricum Red. (P. sibiricum) has been used as a traditional Chinese medicine with a wide range of pharmacology effects. However, the responsible bioactive compounds and their mechanisms of action concerning its antioxidative and anti-hyperuricemic activities remain unexplored. In this work, the antioxidant capacity of P. sibiricum was firstly evaluated with the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azinobis-(3ethylbenzthiazoline)-6-sulfonic acid (ABTS) and ferric-reducing antioxidant power (FRAP) assays, from which the ethyl acetate (EA) fraction exhibited the highest DPPH, ABTS radical scavenging, and ferric-reducing capacities. Meanwhile, the EA fraction displayed the highest total phenolic and flavonoid contents among the four fractions. Next, the potential ligands from the EA fraction were screened out by bio-affinity ultrafiltration liquid chromatography-mass spectrometry (UF-LC-MS) with superoxide dismutase (SOD) and xanthine oxidase (XOD). As a result, N-trans-p-coumaroyloctopamine, N-trans-feruloyloctopamine, N-trans-feruloyltyramine were identified as potential SOD ligands, while N-cis-p-coumaroyltyramine was determined as potential XOD ligand. Additionally, these four ligands effectively interact with SOD and XOD in the molecular docking analysis, with binding energies (BEs) ranging from –6.83 to –6.51 kcal/mol, and the inhibition constants (Ki) from 9.83 to 16.83 μM, which were better than the positive controls. In conclusion, our results indicated that P. sibiricum has good antioxidative and anti-hyperuricemic activities, and its corresponding active ligands targeting SOD and XOD could be explored by the UF-LC-MS method.

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.

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.

The Cordyceps militaris-Derived Polysaccharide CM1 Alleviates Atherosclerosis in LDLR(-/-) Mice by Improving Hyperlipidemia

Atherosclerotic cardiovascular disease has a high mortality worldwide. Our lab previously purified a polysaccharide designated as CM1 with (1→4)-β-D-Glcp and (1→2)-α-D-Manp glycosyls as the backbone. In this study, we investigated the anti-atherosclerosis effect of CM1 and the underlying mechanisms of action in a low-density lipoprotein receptor knockout (LDLR^(-/-) mouse model. It was found that CM1 significantly decreased the formation of atherosclerotic plaques. Mechanistically, CM1 enhanced plasma level of apolipoprotein A-I and decreased the plasma levels of triglyceride, apolipoprotein B, and total cholesterol. In the absence of LDLR, CM1 elevated the expression of very low-density lipoprotein receptor for liver uptake of plasma apolipoprotein B-containing particles and reduced hepatic triglyceride synthesis by inhibiting sterol regulatory element binding protein 1c. CM1 improved lipids excretion by increasing the liver X receptor α/ATP-binding cassette G5 pathway in small intestine. CM1 reduced lipogenesis and lipolysis by inhibiting peroxisome proliferator-activated receptor γ and adipose triglyceride lipase in epididymal fat. Furthermore, CM1 improved lipid profile in C57BL/6J mice. Collectively, CM1 can modulate lipid metabolism by multiple pathways, contributing to reduced plasma lipid level and formation of atherosclerotic plaques in LDLR^(-/-) mice. This molecule could be explored as a potential compound for prevention and treatment of hyperlipidemia and atherosclerosis.

Polygonatum sibiricum polysaccharides (PSP) improve the palmitic acid (PA)-induced inhibition of survival, inflammation, and glucose uptake in skeletal muscle cells

Polygonatum sibiricum polysaccharides (PSP) can decrease the levels of fasting blood glucose, total cholesterol, and triglyceride (TG) in hyperlipidemic and diabetic animals. It can also reduce inflammatory cytokines and promote glucose uptake in adipocytes. However, the underlying molecular mechanisms of PSP in improving insulin resistance (IR) in skeletal muscle remain unclear. In this study, palmitic acid (PA) induced an IR model in L6 myotubes. After treatment, cell proliferation was measured using the CCK8. miR-340-3p, glucose transporter 4 (GLUT-4), and interleukin-1 receptor-associated kinase 3 (IRAK3) expression was measured by qRT-PCR. IRAK3 protein levels were measured by Western blotting. Glucose in the cell supernatant, TG concentration in L6 myotubes, and the levels of IL-1β, IL-6, and TNF-α were measured by an ELISA. We found that cell survival, glucose uptake, and GLUT-4 expression in L6 myotubes were significantly suppressed, while lipid accumulation and inflammatory factor levels were enhanced by PA stimulation. Furthermore, PSP treatment markedly alleviated these effects. Interestingly, PSP also significantly reduced the upregulated expression of miR-340-3p in the L6 myotube model of IR. Furthermore, overexpression of miR-340-3p reversed the beneficial effects of PSP in the same IR model. miR-340-3p can bind to the 3′-untranslated regions of IRAK3. Additionally, PA treatment inhibited IRAK3 expression, whereas PSP treatment enhanced IRAK3 expression in L6 myotubes. Additionally, miR-340-3p also inhibited IRAK3 expression in L6 myotubes. Taken together, PSP improved inflammation and glucose uptake in PA-treated L6 myotubes by regulating miR-340-3p/IRAK3, suggesting that PSP may be suitable as a novel therapeutic agent for IR.

Physicochemical, morpho-structural, and biological characterization of polysaccharides from three Polygonatum spp

Polygonatum species, including P. cyrtonema, P. kingianum, and P. sibiricum, are edible plants with medicinal purposes, which have long been consumed as food due to their high nutritional value. In this study, polysaccharides from P. cyrtonema (PCP), P. kingianum (PKP) and P. sibiricum (PSP) were obtained, and their physicochemical properties and in vitro biological activities were investigated. Our results demonstrated that PCP, PKP, and PSP consist of major fructose and minor glucose, galacturonic acid, and galactose in different molar ratios with the molecular weights of 8.5 × 10³ Da, 8.7 × 10³ Da, and 1.0 × 10⁴ Da, respectively. The three polysaccharides had triple-helical structures with β-d-Fruf, α-d-Glcp, α-d-Galp sugar residues, and an O-acetyl group, and displayed peak-shaped structures in different sizes. They also exhibited thermal, shear-thinning behavior and viscoelastic properties, and PCP presented the highest viscoelasticity. Moreover, they exerted strong free radical-scavenging abilities, and significant reducing capacity. PCP was the strongest, followed by PSP and then PKP. They significantly promoted the polarization of the M1 macrophage, with the effect of PCP ranking first. All three had similar effects on GLP-1 secretion. It is, therefore, necessary to identify the various roles of these three Polygonatum polysaccharides as functional agents based on their bioactivities and physicochemical properties.

Three Polygonatum polysaccharides with different physicochemical properties exert distinct effects on free radical-scavenging abilities and the promotion of M1 macrophage polarization, while they have similar effects on GLP-1 secretion.

Transcriptomic responses to drought stress in Polygonatum kingianum tuber

BACKGROUND

Polygonatum kingianum Coll. et Hemsl. is an important plant in Traditional Chinese Medicine. The extracts from its tubers are rich in polysaccharides and other metabolites such as saponins. It is a well-known concept that growing medicinal plants in semi-arid (or drought stress) increases their natural compounds concentrations. This study was conducted to explore the morpho-physiological responses of P. kingianum plants and transcriptomic signatures of P. kingianum tubers exposed to mild, moderate, and severe drought and rewatering.

RESULTS

The stress effects on the morpho-physiological parameters were dependent on the intensity of the drought stress. The leaf area, relative water content, chlorophyll content, and shoot fresh weight decreased whereas electrolyte leakage increased with increase in drought stress intensity. A total of 53,081 unigenes were obtained; 59% of which were annotated. We observed that 1352 and 350 core genes were differentially expressed in drought and rewatering, respectively. Drought stress driven differentially expressed genes (DEGs) were enriched in phenylpropanoid biosynthesis, flavonoid biosynthesis, starch and sucrose metabolism, and stilbenoid diarylheptanoid and gingerol biosynthesis, and carotenoid biosynthesis pathways. Pathways such as plant-pathogen interaction and galactose metabolism were differentially regulated between severe drought and rewatering. Drought reduced the expression of lignin, gingerol, and flavonoid biosynthesis related genes and rewatering recovered the tubers from stress by increasing the expression of the genes. Increased expression of carotenoid biosynthesis pathway related genes under drought suggested their important role in stress endurance. An increase in starch and sucrose biosynthesis was evident from transcriptomic changes under drought stress. Rewatering recovered the drought affected tubers as evident from the contrasting expression profiles of genes related to these pathways. P. kingianum tuber experiences an increased biosynthesis of sucrose, starch, and carotenoid under drought stress. Drought decreases the flavonoids, phenylpropanoids, gingerol, and lignin biosynthesis. These changes can be reversed by rewatering the P. kingianum plants.

CONCLUSIONS

These results provide a transcriptome resource for P. kingianum and expands the knowledge on the effect of drought and rewatering on important pathways. This study also provides a large number of candidate genes that could be manipulated for drought stress tolerance and managing the polysaccharide and secondary metabolites' contents in P. kingianum.

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.

Effect of steaming process on the structural characteristics and antioxidant activities of polysaccharides from Polygonatum sibiricum rhizomes

Polygonatum sibiricum (P. sibiricum) rhizomes are widely used as a tonic and functional food, and are often processed to enhance their tonic function by repeated steaming and drying. As the most important constituent, the polysaccharide from P. sibiricum rhizomes (PSP) has demonstrated various activities, but the alteration of structural characteristics and activities of the purified PSPs during steaming process was rarely investigated. To well understand the effect of steaming process on the polysaccharides of P. sibiricum, neutral polysaccharides from P. sibiricum rhizomes (PSP0 ~ PSP9) after steaming were first isolated and purified, and then the chemical properties and antioxidant activities were determined. The results showed that the molar ratios of monosaccharides in PSPs were different. The molecular weights of PSPs were increased significantly after the fourth steaming. Morphological studies showed that the surface of PSPs became much tighter during the steaming process. Fourier transform infrared spectroscopy spectra displayed the polysaccharides had similar backbones and chemical groups. Furthermore, the antioxidant activity of PSPs was measured through radical scavenging tests. It was found that the radical scavenging activity of PSPs was elevated strikingly after steaming, and increased gradually with numbers of steaming process. The biological and chemical variance of PSPs revealed considerable segregation of PSP0, PSP1 ~ PSP4 and PSP5 ~ PSP9. In conclusion, our results proposed the fourth time as the optimal number of steaming to extract functional polysaccharide from P. sibiricum rhizomes.

Development of Broad-Spectrum Antiviral Agents-Inspiration from Immunomodulatory Natural Products

Developing broad-spectrum antiviral drugs remains an important issue as viral infections continue to threaten public health. Host-directed therapy is a method that focuses on potential targets in host cells or the body, instead of viral proteins. Its antiviral effects are achieved by disturbing the life cycles of pathogens or modulating immunity. In this review, we focus on the development of broad-spectrum antiviral drugs that enhance the immune response. Some natural products present antiviral effects mediated by enhancing immunity, and their structures and mechanisms are summarized here. Natural products with immunomodulatory effects are also discussed, although their antiviral effects remain unknown. Given the power of immunity and the feasibility of host-directed therapy, we argue that both of these categories of natural products provide clues that may be beneficial for the discovery of broad-spectrum antiviral drugs.

Polysaccharide-rich extract from Polygonatum sibiricum protects hematopoiesis in bone marrow suppressed by triple negative breast cancer

Polysaccharide is one of main components in Polygonatum sibiricum (PS), which is an herbal medicine widely used in East Asia. Polysaccharides from Polygonatum sibiricum has been shown to exhibit multiple biological activities, such as anti-diabetes, anti-inflammation, antioxidant, immunity modulation, and anticancer. Since hematopoietic system is one of determinant factors in cancer control, we here explored the effect of polysaccharide-rich extract from Polygonatum sibiricum (PREPS) on hematopoiesis in the mice bearing triple negative breast cancer (TNBC). We found that the 4T1 TNBC tumor significantly increased myeloid cells in peripheral blood, bone marrow and spleen, while decreasing bone marrow hematopoietic stem and progenitor cells (HSPCs), indicative of an inhibition of medullary hematopoiesis. When 4T1 TNBC tumor-bearing mice were treated with PREPS, the percentage of myeloid cells within tumor-infiltrating immune cells was reduced. In addition, PREPS also inhibited hematopoietic cell expansion in the spleen, which was induced by TNBC tumors. Importantly, PREPS markedly increased HSPCs and common lymphoid progenitors in the bone marrow that had been suppressed by TNBC tumors. These findings suggest that PREPS protect hematopoiesis inhibited by TNBC tumors in the bone marrow. Although PREPS alone did not achieve statistical significance in the suppression of TNBC tumor growth, it may have a long-lasting anti-tumor effect to assist TNBC therapies by sustaining hematopoiesis and lymphoid regeneration in bone marrow.

Protective Effect of Polygonatum sibiricum Polysaccharides on Apoptosis, Inflammation, and Oxidative Stress in Nucleus Pulposus Cells of Rats with the Degeneration of the Intervertebral Disc

Objective. Polygonatum sibiricum polysaccharide (PSP) has antioxidant activity, immune enhancement, and other biological properties. However, the effect of PSP on intervertebral disc degeneration has not been reported. In this study, we mainly investigated the effect of PSP on the apoptosis, inflammation, and oxidative stress of nucleus pulposus cells (NPCs) during the process of intervertebral disc degeneration. Methods. A rat NPC model induced by H2O2 was constructed. The CCK8 method was used to measure the effects of PSP on the apoptosis of rat NPCs induced by H2O2. The effects on the activity of SOD and content of MDA were also determined. The rat model of intervertebral disc degeneration was treated with PSP for 1 month, and the mRNA expression levels of IL-1β, COX2, iNOS, Col2α1, Col10α1, and MMP3 were measured by qPCR in the tissue of intervertebral disc. NPCs from the degenerated intervertebral discs were separated, and the cell viability was measured by the CCK8 method. The contents of SOD and MDA in NPCs were determined as well. Results. PSP significantly reduced the apoptosis of NPCs induced by H2O2, significantly increased the SOD content, and decreased the content of MDA in H2O2-induced NPCs. The expression level of IL-1β, COX2, and iNOS in the rat model with intervertebral disc degeneration was significantly downregulated after 1 month of PSP treatment. PSP treatment increased the expression of Col2α1 type and significantly decreased the expression of Col10α1 type collagen and MMP3 in rats with disc degeneration. PSP treatment significantly reduced NPC apoptosis and increased its SOD content and reduced MDA content, which is consistent with the results from cell-level experiments. Conclusion. PSP can effectively reduce the apoptosis, inflammation, and oxidative stress of H2O2-induced NPCs in rats with intervertebral disc degeneration and mitigate the progression of intervertebral disc degeneration, which has the potential to be developed as new drugs for the treatment of intervertebral disc degeneration.

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.

Steroidal saponins from the rhizome of Polygonatum sibiricum

Four new steroidal saponins, 3-O-β-D-glucopyranosyl(1→4)-β-D-fucopyranosyl -(25R)-spirost-5-en-3β,17α-diol (1), 3-O-β-D-glucopyranosyl(1→4)-β-D- fucopyranosyl-(25S)-spirost-5-en-3β,17α-diol (2), 3-O-β-D-glucopyranosyl(1→2) -β-D-glucopyranosyl(1→4)-β-D-fucopyranosyl-(25R)-spirost-5-en-3β,17α-diol (3), 3-O-β-D-glucopyranosyl(1→4)-β-D-fucopyranosyl-(25R/S)-spirost-5-en-3β,12β-diol (4), together with five known steroidal saponins were isolated from the ethanolic extract of the rhizome of Polygonatum sibiricum. Chemical structures of these compounds were elucidated by spectroscopic techniques. Anti-inflammatory activities of these new compounds were evaluated.

Effect of sulfation and partial hydrolysis of polysaccharides from Polygonatum sibiricum on immune-enhancement

The aqueous polysaccharide from Polygonatum sibiricum was extracted and fractionated using anion-exchange chromatography to obtain F₁ fraction. The F₁ was chemically sulfated and partially acid-hydrolyzed for the production of its over-sulfated (OS_1,2,3) and hydrolyzed (HP_1,2,3) derivatives, in which the sulfate content of OS_1,2,3 was 7.5-17.1%, and the M_w of HP_1,2,3 ranged from 18.2 × 10³ to 57.3 × 10³ g/mol. Considerable RAW264.7 cell activation was observed by HP_1,2,3 with NO production of 34.9, 44.3 and 42.7 μM, respectively, as well as the mRNA expression of cytokines (IL-1β, IL-6, IL-10 and IL-12). NK cell cytotoxicity against HT-29 cell was facilitated by OS_1,2,3 treatment with the increased gene expressions of INF-γ, Granzyme-B, perforin, NKG2D, and FasL. RAW264.7 cells appeared to be activated via MR and TLR4 mediated signaling pathway, but CR3 and TRL2 might play a main role in stimulating NK cells. Overall, the present study suggests the potential application of polysaccharides from P. sibiricum in functional foods and pharmacological industries.

A Review: The Bioactivities and Pharmacological Applications of Polygonatum sibiricum polysaccharides

Traditional Chinese Medicine (TCM) has been widely used in China and is regarded as the most important therapeutic. Polygonatum sibiricum (PS), a natural plant used in traditional Chinese medicine, has various functions associated with a number of its components. There are many compositions in PS including polysaccharides, steroids, anthraquinone, alkaloids, cardiac glycosides, lignin, vitamins, various acids, and so on. Of these, polysaccharides play a significant role in PS-based therapeutics. This article summarizes Polygonatum sibiricum polysaccharides (PSP) have many pharmacological applications and biological activities, such as their antioxidant activity, anti-aging activity, an anti-fatigue effect, immunity enhancement effect, antibacterial effect, anti-inflammatory effect, hypolipidemic and antiatherosclerotic effects, anti-osteoporosis effect, liver protection, treatment of diabetes mellitus (DM), anti-cancer effect, and may help prevent Alzheimer’s disease, and so on. This review summarized the extraction method, purification method, compositions, pharmacological applications, biological activities, biosynthesis, and prospects of PSP, providing a basis for further study of PS and PSP.

Polygonatum sibiricum polysaccharides play anti-cancer effect through TLR4-MAPK/NF-κB signaling pathways

OBJECTIVE

To investigate the anti-cancer effect of Polygonatum sibiricum polysaccharides (PSP) and the underlying mechanism.

METHODS

Tumor-bearing mice were randomly divided into normal saline (NS) group, adriamycin (ADM) group, PSP group and lipopolysaccharide (LPS) group. RAW264.7 cells were pre-treated with or without TLR4 inhibitor or MyD88 inhibitor. Quantitative RT-PCR and Western blot were performed to detect the mRNA and protein expressions, respectively. ELISA and Griess reaction was used to measure cytokines and NO levels. Flow cytometry was employed to examine T-lymphocyte subset and CCK-8 assay was used for cell viability.

RESULTS

The in vivo experiment found that PSP inhibited tumor growth and improved the spleen index, thymus index, the cytokines secretion and CD4⁺/CD8⁺ lymphocytes ratio. Compared with the NS group, the mRNA and protein expressions of the critical nodes inTLR4-MAPK/NF-κB signaling pathways (except TRAM) significantly increased in PSP group, as well as the NO and cytokines levels. Nevertheless, PSP had no obvious effects on TRAM. Further analysis showed that PSP effects on the critical nodes in TLR4-MAPK/NF-κB signaling pathways were suppressed by inhibitor in vitro.

CONCLUSION

The immunoenhancement effect of PSP against lung cancer is mediated by TLR4-MAPK/NF-κB signaling pathways.