Protective effects of Polygonatum kingianum polysaccharides and aqueous extract on uranium-induced toxicity in human kidney (HK-2) cells

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.

Polygonatum kingianum Polysaccharides Enhance the Preventive Efficacy of Heat-Inactivated Limosilactobacillus reuteri WX-94 against High-Fat-High-Sucrose-Induced Liver Injury and Gut Dysbacteriosis

Limosilactobacillus reuteri (L. reuteri) is an efficacious probiotic that could reduce inflammation and prevent metabolic disorders. Here, we innovatively found that Polygonatum kingianum polysaccharides (PKP) promoted proliferation and increased stability of L. reuteri WX-94 (a probiotic strain showing anti-inflammation potentials) in simulated digestive fluids in vitro. PKP was composed of galactose, glucose, mannose, and arabinose. The cell-free supernatant extracted from L. reuteri cultured with PKP increased ABTS•+, DPPH•, and FRAP scavenging capacities compared with the supernatant of the medium without PKP and increased metabolites with health-promoting activities, e.g., 3-phenyllactic acid, indole-3-lactic acid, indole-3-carbinol, and propionic acid. Moreover, PKP enhanced alleviating effects of heat-inactivated L. reuteri on high-fat-high-sucrose-induced liver injury in rats via reducing inflammation and regulating expressions of protein and genes involved in fatty acid metabolism (such as HIF1-α, FAβO, CPT1, and AMPK) and fatty acid profiles in liver. Such benefits correlated with its prominent effects on enriching Lactobacillus and short-chain fatty acids while reducing Dubosiella, Fusicatenilacter, Helicobacter, and Oscillospira. Our work provides novel insights into the probiotic property of PKP and emphasizes the great potential of the inactivated L. reuteri cultured with PKP in contracting unhealthy diet-induced liver dysfunctions and gut dysbacteriosis.

Identification of carbohydrate in Polygonatum kingianum Coll. et Hemsl and inhibiting oxidative stress

The specific structure of Polygonatum kingianum Coll. et Hemsl polysaccharide (PKP) has been rarely reported. In this study, an inulin-type fructan PKP-1, was extracted and purified from Polygonatum kingianum Coll. et Hemsl, and its structural characteristics and antioxidants activity were evaluated. The molecular weights of PKP-1 was determined to be 4.802 kDa. Monosaccharide composition analysis evidenced that PKP-1 was composed of galactose, glucose and fructose in a molar ratio of 0.8 %:7.2 %:92.0 %. Glycosidic linkage and Nuclear Magnetic Resonance (NMR) analysis revealed that PKP-1 exhibited a primary sugar residue linkage of →1-β-d-Fruf-2→2,6-β-d-Fruf-1→, where β-d-Fruf-2→ acts as the side chain and links to the C-6 position of →2,6-β-d-Fruf-1→. In vitro antioxidant activity assays demonstrated that PKP-1 enhanced the mitigation of hepatic oxidative stress in HepG2 cells induced by free fatty acids. This effect was marked by increased enzymatic activities of superoxidase dismutase (SOD) and catalase (CAT), along with elevated glutathione (GSH) levels. These findings indicate that PKP-1 could be used as a potential natural antioxidant.

Molecular mechanism of Rhizoma Polygonati in the treatment of nephrolithiasis: network pharmacology analysis and in vivo experimental verification

Rhizoma Polygonati (RP) is the dried rhizome of the liliaceous plant. It has anti-inflammatory and anti-apoptosis effects. But its role in kidney stones has not been studied. The purpose of this study was to verify the effect of RP in the treatment of nephrolithiasis through network pharmacological analysis and in vivo experiments. The active compounds and protein targets of RP, as well as the potential targets of the nephrolithiasis were searched from the database. The protein-protein interaction (PPI) network diagram and the drug-compounds-targets-disease network were constructed. The enrichment analysis was performed by Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG). Subsequently, the effect of RP on the prevention and treatment of nephrolithiasis was experimentally validated in vivo. Animal experiments showed that RP ameliorates renal function and reduced crystal deposition in a mouse model. It may act through anti-inflammation and anti-apoptosis. Our study showed that RP could prevent and treat nephrolithiasis by inhibiting apoptosis and inflammation, which provided a new efficacy and clinical application for RP.

U(VI) exposure induces apoptosis and pyroptosis in RAW264.7 cells

U(VI) pollution has already led to serious harm to the environment and human health with the increase of human activities. The viability of RAW264.7 cells was assessed under various U(VI) concentration stress for 24 and 48 h. The reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and superoxide dismutase (SOD) activities of RAW264.7 cells under U(VI) stress were measured. The results showed that U(VI) decreased cell activity, induced intracellular ROS production, abnormal MMP, and increased SOD activity. The flow cytometry with Annexin-V/PI double labeling demonstrated that the rate of late apoptosis increased with the increase of U(VI) concentration, resulting in decreased Bcl-2 expression and increased Bax expression. The morphology of RAW264.7 cells dramatically changed after 48 h U(VI) exposure, including the evident bubble phenomenon. Besides, U(VI) also increased the proportion of LDH releases and increased GSDMD, and Ras, p38, JNK, and ERK1/2 protein expression, which indicated that the MAPK pathway was also involved. Therefore, U(VI) ultimately led to apoptosis and pyroptosis in RAW264.7 cells. This study offered convincing proof of U(VI) immunotoxicity and established the theoretical framework for further fundamental studies on U(VI) toxicity.

Depleted uranium induces thyroid damage through activation of ER stress via the thrombospondin 1-PERK pathway

Depleted uranium (DU) can cause damage to the body, but its effects on the thyroid are unclear. The purpose of this study was to investigate the DU-induced thyroid damage and its potential mechanism in order to find new targets for detoxification after DU poisoning. A model of acute exposure to DU was constructed in rats. It was observed that DU accumulated in the thyroid, induced thyroid structure disorder and cell apoptosis, and decreased the serum T4 and FT4 levels. Gene screening showed that thrombospondin 1 (TSP-1) was a sensitive gene of DU, and the expression of TSP-1 decreased with the increase of DU exposure dose and time. TSP-1 knockout mice exposed to DU had more severe thyroid damage and lower serum FT4 and T4 levels than wild-type mice. Inhibiting the expression of TSP-1 in FRTL-5 cells aggravated DU-induced apoptosis, while exogenous TSP-1 protein alleviated the decreased viability in FRTL-5 cells caused by DU. It was suggested that DU may caused thyroid damage by down-regulating TSP-1. It was also found that DU increased the expressions of PERK, CHOP, and Caspase-3, and 4-Phenylbutyric (4-PBA) alleviated the DU-induced FRTL-5 cell viability decline and the decrease levels of rat serum FT4 and T4 caused by DU. After DU exposure, the PERK expression was further up-regulated in TSP-1 knockout mice, and the increased expression of PERK was alleviated in TSP-1 over-expressed cells, as well as the increased expression of CHOP and Caspase-3. Further verification showed that inhibition of PERK expression could reduce the DU-induced increased expression of CHOP and Caspase-3. These findings shed light on the mechanism that DU may activate ER stress via the TSP 1-PERK pathway, thereby leading to thyroid damage, and suggest that TSP-1 may be a potential therapeutic target for DU-induced thyroid damage.

Structural characterization and anti-inflammatory activity of a novel polysaccharide PKP2-1 from Polygonatum kingianum

Introduction

This study aimed to investigate the structure characterization and antiinflammatory activity of a novel polysaccharide, PKP2-1, from the rhizomes of Polygonatum kingianum Coll. and Hemsl.

Methods

We isolated a novel polysaccharide, PKP2-1, from the rhizomes of Polygonatum kingianum Coll. and Hemsl. for the first time, which was then successively purified through hot-water extraction, 80% alcohol precipitation, anion exchange and gel permeation chromatography. The in vitro anti-inflammatory activity of PKP2-1 in MH7A cells was assessed using a CCK-8 kit assay.

Results

Monosaccharide composition assay revealed that PKP2-1 was mainly composed of glucose, galactose, mannose, and glucuronic acid at an approximate molar ratio of 6:2:2:1. It had a molecular weight of approximately 17.34 kDa. Structural investigation revealed that the backbone of PKP2-1 consisted of (→2, 3)-α-D-Galp(4→, →2)-α-D-Manp(3→, →2)-β-D-Glcp(4→) and α-D-Glcp(3→) residues with side chains (→2)-β-D-Glcp(4→, →1)-α-D-Galp(4→) and α-D-Glcp(3→) branches located at O-3 position of (→2, 3)-α-D-Galp(4→). The in vitro anti-inflammatory activity of PKP2-1 in MH7A cells revealed that PKP2-1 could reduce the expression of IL-11β and IL-6, increase the expression of IL-10 and induce apoptosis of synovial fibroblasts.

Conclusion

The PKP2-1 could inhibit MH7A cell growth and potentially be exploited as an anti-inflammatory agent.

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.

Oxidative Stress and Mitochondrial Dysfunction in Chronic Kidney Disease

The kidney contains many mitochondria that generate ATP to provide energy for cellular processes. Oxidative stress injury can be caused by impaired mitochondria with excessive levels of reactive oxygen species. Accumulating evidence has indicated a relationship between oxidative stress and kidney diseases, and revealed new insights into mitochondria-targeted therapeutics for renal injury. Improving mitochondrial homeostasis, increasing mitochondrial biogenesis, and balancing mitochondrial turnover has the potential to protect renal function against oxidative stress. Although there are some reviews that addressed this issue, the articles summarizing the relationship between mitochondria-targeted effects and the risk factors of renal failure are still few. In this review, we integrate recent studies on oxidative stress and mitochondrial function in kidney diseases, especially chronic kidney disease. We organized the causes and risk factors of oxidative stress in the kidneys based in their mitochondria-targeted effects. This review also listed the possible candidates for clinical therapeutics of kidney diseases by modulating mitochondrial function.

A Review of Polygonatum Mill. Genus: Its Taxonomy, Chemical Constituents, and Pharmacological Effect Due to Processing Changes

Ethnopharmacological relevance: The genus Polygonatum Tourn, ex Mill. contains numerous chemical components, such as steroidal saponins, polysaccharides, flavonoids, alkaloids, and others, it possesses diverse pharmacological activities, such as anti-aging, anti-tumor, immunological regulation, as well as blood glucose management and fat reducing properties. Aim of the review: This study reviews the current state of research on the systematic categorization, chemical composition, pharmacological effects, and processing changes of the plants belonging to the genus Polygonatum, to provide a theoretical foundation for their scientific development and rational application. Materials and methods: The information was obtained by searching the scientific literature published between 1977 and 2022 on online databases (including PubMed, CNKI, SciFinder, and Web of Science) and other sources (such as the Chinese Pharmacopoeia 2020 edition, and Chinese herbal books). Results: The genus Polygonatum contains 79 species, and 233 bioactive chemical compounds were identified in them. The abundance of pharmacological activities, such as antioxidant activities, anti-fatigue activities, anti-inflammatory activities, etc., were revealed for the representatives of this genus. In addition, there are numerous processing methods, and many chemical constituents and pharmacological activities change after the unappropriated processing. Conclusions: This review summarizes the taxonomy classification, chemical composition, pharmacological effects, and processing of the plants belonging to the genus Polygonatum, providing references and research tendencies for plant-based drug development and further clinical applications.