Notoginsenoside R1 attenuates high glucose-induced endothelial damage in rat retinal capillary endothelial cells by modulating the intracellular redox state

The Therapeutic Effect and Mechanism of Traditional Chinese Medicine in Type 2 Diabetes Mellitus and Its Complications

Traditional Chinese Medicine (TCM) has recently emerged as a beacon for the treatment of diabetes and its complications. Many TCMs that are commonly used, have the potentially demonstrated significant anti-diabetic effects. The mechanisms of these effects have been extensively discussed using modern techniques, such as genomics, mass spectrometry, and network pharmacology. Studies have demonstrated that TCM can influence glucose metabolism and pancreatic function via a diverse array of mechanisms including PI3K/AKT and AMPK pathways. TCM not only exhibits potential in the treatment of diabetes but also reduces the risk of diabetic complications. It is effective in the treatment of diabetic nephropathy (DN), diabetic retinopathy (DR), diabetic neuropathy (DPN), diabetic cardiomyopathy, and peripheral angiopathy. Research has demonstrated that prescriptions, Chinese herbal medicines, and their extracts play a role in a variety of molecular mechanisms such as antioxidation, apoptosis regulation, hypoxia improvement, autophagy, and promotion of glucose and lipid metabolism. The antioxidant properties of TCM have received considerable attention. Recent studies have demonstrated that they are capable of effectively eliminating free radicals from the body and reducing damage to cells caused by oxidative stress. Consequently, they are crucial in the treatment of diabetes and its associated complications. This review summarizes the ever-expanding scope of TCM applicability in the field of diabetes, providing crucial support and innovative ideas for modern healthcare. TCMs could help seek more effective pharmacological targets in basic study and as well serve as the complement to the strategy of diabetic prevention and treatment benefiting the patients. More and more large series of RCT and clinical investigations will eventually examine the efficacy of specific TCM formulas on the therapeutic effect of DM and its complication where currently treatments could not be satisfied.

Ginsenoside in the treatment of type 2 diabetes and its complications: a promising traditional chinese medicine

Type 2 diabetes mellitus (T2DM), a chronic condition commonly observed in adults, particularly among the elderly, is characterized by a dysfunctional insulin response that impairs blood glucose regulation, resulting in persistent hyperglycemia. Ginseng, a medicinal plant with significant economic value and a longstanding history of therapeutic use in Asia, has shown efficacy against various diseases. Extensive clinical and experimental studies highlight ginsenosides, its primary bioactive compounds, for their multiple therapeutic effects across a range of conditions, including endocrine, cardiovascular, and central nervous system disorders. Various ginsenoside types have demonstrated potential in lowering blood glucose levels, reducing insulin resistance, and alleviating complications through the modulation of key protein targets and signaling pathways. This review consolidates the pharmacological actions and mechanisms of distinct ginsenosides in managing diabetes and its complications, offering a theoretical foundation for further pharmacological research and novel drug development for T2DM treatment, while also providing robust theoretical support for future clinical applications.

Isoquercetin Alleviates Diabetic Retinopathy Via Inhibiting p53-Mediated Ferroptosis

Diabetic retinopathy (DR) is a retinal vasculopathy stemming from diabetes mellitus, characterized by microvascular changes in the retina that can lead to visual impairment or even blindness. Ferroptosis, a form of regulated cell death driven by iron accumulation and lipid peroxidation, has been implicated in the progression of DR. Isoquercetin (IQC), a flavonoid compound, has been shown to inhibit cellular ferroptosis and apoptosis, yet its specific role and underlying mechanisms in DR remain to be elucidated. The present study aimed to investigate the effects of IQC on DR and to delineate its protective mechanisms, particularly focusing on whether these effects are mediated through p53. We employed streptozotocin-induced diabetic C57BL/J mouse models and high glucose (HG)-induced human retinal capillary endothelial cells (HRCECs) models for both in vivo and in vitro experiments. Pathological damage was assessed using hematoxylin and eosin staining, while cell apoptosis rates was detected by TUNEL staining and FITC/PI flow cytometry. Mitochondrial damage was evaluated using transmission electron microscopy. Additionally, we measured levels of reactive oxygen species (ROS) and glutathione (GSH) to assess lipid peroxidation and quantified ferrous ions (Fe2+). Protein expression was detected by immunofluorescence and western blot analysis, and mRNA levels were determined by real-time quantitative PCR. Our findings revealed that IQC mitigated retinal damage in diabetic mice, and in vitro studies further demonstrated that this effect was mediated by the inhibition of p53. In HG-induced HRCECs, we observed decreased cell viability, lipid peroxidation, and ferroptosis. IQC alleviated HG-induced ferroptosis in HRCECs by modulating the p53 pathway, which exhibited varying responses following p53 inhibition or activation. In summary, IQC downregulated the p53 signaling pathway, thereby reducing ferroptosis and apoptosis, and effectively ameliorated the damage associated with DR. These discoveries offer novel insights into the protective mechanisms of IQC in DR.

Notoginsenoside R1 reduces acquired lymphedema and increases lymphangiogenesis by promoting VEGF-C expression via cAMP/PKA/CREB signaling

BACKGROUND

Acquired lymphedema is a global health concern with limited treatment options. While vascular endothelial growth factor C (VEGF-C) administration has shown promise for the treatment of this patient population, no small-molecule compounds have hitherto been identified to improve lymphedema by stimulating VEGF-C expression and lymphangiogenesis.

OBJECTIVE

This study investigated the therapeutic effect of notoginsenoside R1 (R1) on a mouse model of tail acquired lymphedema and explored the underlying mechanisms.

METHODS

C57BL/6J mice and lymphatic endothelial cells (LECs) specific VEGFR-3 knockout transgenic mice underwent surgical induction of tail acquired lymphedema. Tail circumference, lymphatic drainage function, VEGF-C expression, and lymphangiogenesis were measured. LECs' function was assessed using wound healing and tube formation assays. Quantitative PCR (q-PCR) and western blot were conducted to measure VEGF-C expression levels. In addition, RNA sequencing analysis and western blot were performed to elucidate the signal pathways involved. Luciferase reporter assays assessed VEGF-C promoter activity.

RESULTS

R1 treatment improved lymphedema, lymphatic function, and lymphangiogenesis in the mouse model. R1 enhanced migration, tube formation, and VEGF-C expression of LECs. These effects were abolished by VEGF-C siRNA and VEGFR-3 inhibitors. VEGFR3 knockout in LECs completely blocked R1's ability to promote lymphangiogenesis and lymphatic drainage while partially but significantly reducing its improvement on lymphedema. R1 activated the cAMP/PKA signaling pathway, leading to PKA and CREB phosphorylation. The PKA inhibitor and CREB siRNA inhibited R1-induced VEGF-C expression. Additionally, R1 activated VEGF-C promoter activity in a CREB-dependent manner.

CONCLUSION

R1 emerges as the first reported small natural compound to promote VEGF-C expression. It reduces acquired lymphedema and enhances lymphangiogenesis via the cAMP/PKA/CREB signaling pathway. These findings suggest R1 as a potential novel oral medication for treating acquired lymphedema patients.

Study on the mechanism of plant metabolites to intervene oxidative stress in diabetic retinopathy

Diabetic retinopathy is the main microvascular complication of diabetes and the first blinding eye disease in the working-age population. Oxidative stress is an important pathogenesis of diabetic retinopathy. Plant metabolites can be divided into two types: primary metabolites and secondary metabolites, secondary metabolites are the main active components and important sources for developing new drugs. It has unique effect in the treatment of diabetic retinopathy. However, the research on the intervention mechanism of plant metabolites in diabetic retinopathy are still relatively shallow, which limit the application of plant metabolites. With the deepening of research, more and more plant metabolites have been reported to play a role in treating diabetic retinopathy through anti-oxidative stress, including polyphenols, polysaccharides, saponins, alkaloids, etc. Therefore, this article reviewed the potential of plant metabolites in the treatment of diabetic retinopathy in the last 10 years and elucidated their mechanism of action. We hope to provide some references for the application of plant metabolites and provide valuable resources for the research and development of new drugs for diabetic retinopathy.

Pharmacokinetics and Biological Activities of Notoginsenoside R1: A Systematical Review

Panax notoginseng (PN) root is a renowned nutritional supplement, health food additive, and traditional medicine that maintains homeostasis within the human microcirculatory system. Notoginsenoside R1 (NG-R1), an active compound derived from PN root, has been reported to possess various pharmacological activities, including anti-inflammatory, antioxidant, anticancer, antimicrobial, and angiogenic effects. However, NG-R1's pharmacokinetic properties and pharmacological activities have not been systematically elucidated. In this paper, the pharmacokinetic properties of NG-R1, its pharmacological effects, mechanisms of actions, and structure-activity relationship have been reviewed. Notably, NG-R1 inhibits tumor necrosis factor α (TNF-α) expression, enhances the expression of nuclear factor erythroid 2-related factor 2 (NRF2), and enhances the expression of vascular endothelial growth factor receptor (VEGFR). The pharmacological effects of NG-R1 are associated with the modulation of several signaling pathways, such as mitogen-activated protein kinase (MAPK)/nuclear factor κ-B (NF-κB), NRF2/antioxidant response element (ARE), Wnt/β-catenin, and phosphoinositide-3 kinase (PI3K)/protein kinase B (AKT). NG-R1 offers potentially protective effects against numerous diseases, including cardiovascular, neurological, renal, pulmonary, bone, and diabetes-related conditions. Although the pharmacological activities and diverse effects of NG-R1 have been demonstrated in various diseases, its clinical applications are limited by poor bioavailability. Several strategies have been explored to improve the pharmacokinetic profile of NG-R1, making it a promising candidate for drug development.

Underlying mechanisms of traditional Chinese medicine in the prevention and treatment of diabetic retinopathy: Evidences from molecular and clinical studies

As one of the most serious microvascular complications of diabetes mellitus (DM), diabetic retinopathy (DR) can cause visual impairment and even blindness. With the rapid increase in the prevalence of DM, the incidence of DR is also rising year by year. Preventing and effectively treating DR has become a major focus in the medical field. Traditional Chinese medicine (TCM) has a wealth of experience in treating DR and has achieved significant results with various herbs and TCM prescriptions. Traditional Chinese Medicine (TCM) provides a comprehensive therapeutic strategy for diabetic retinopathy (DR), encompassing anti-inflammatory and antioxidant actions, anti-neovascularization, neuroprotection, regulation of glucose metabolism, and inhibition of apoptosis. This review provides an overview of the current status of TCM treatment for DR in recent years, including experimental studies and clinical researches, to explore the clinical efficacy and the underlying modern mechanisms of herbs and TCM prescriptions. Besides, we also discussed the challenges TCM faces in treating DR, such as drug-drug interactions among TCM components and the lack of high-quality evidence-based medicine practice, which pose significant obstacles to TCM's application in DR.

Natural plant medications for the treatment of retinal diseases: The blood-retinal barrier as a clue

BACKGROUND

Retinal diseases significantly contribute to the global burden of visual impairment and blindness. The occurrence of retinal diseases is often accompanied by destruction of the blood‒retinal barrier, a vital physiological structure responsible for maintaining the stability of the retinal microenvironment. However, detailed summaries of the factors damage the blood‒retinal barrier and treatment methods involving natural plant medications are lacking.

PURPOSE

To comprehensively summarize and analyze the protective effects of active substances in natural plant medications on damage to the blood-retina barrier that occurs when retinal illnesses, particularly diabetic retinopathy, and examine their medicinal value and future development prospects.

METHODS

In this study, we searched for studies published in the ScienceDirect, PubMed, and Web of Science databases. The keywords used included natural plant medications, plants, natural herbs, blood retinal barrier, retinal diseases, diabetic retinopathy, age-related macular degeneration, and uveitis. Chinese herbal compound articles, non-English articles, warning journals, and duplicates were excluded from the analysis.

RESULTS

The blood‒retinal barrier is susceptible to high glucose, aging, immune responses, and other factors that destroy retinal homeostasis, resulting in pathological changes such as apoptosis and increased vascular permeability. Existing studies have shown that the active compounds or extracts of many natural plants have the effect of repairing blood-retinal barrier dysfunction. Notably, berberine, puerarin, and Lycium barbarum polysaccharides exhibited remarkable therapeutic effects. Additionally, curcumin, astragaloside IV, hesperidin, resveratrol, ginsenoside Rb1, luteolin, and Panax notoginseng saponins can effectively protect the blood‒retinal barrier by interfering with distinct pathways. The active ingredients found in natural plant medications primarily repair the blood‒retinal barrier by modulating pathological factors such as oxidative stress, inflammation, pyroptosis, and autophagy, thereby alleviating retinal diseases.

CONCLUSION

This review summarizes a series of plant extracts and plant active compounds that can treat retinal diseases by preventing and treating blood‒retinal barrier damage and provides reference for the research of new drugs for treating retinal diseases.

Notoginsenoside-R1 ameliorates palmitic acid-induced insulin resistance and oxidative stress in HUVEC via Nrf2/ARE pathway

Panax notoginseng, a Chinese traditional food and herb medicine, possesses notable cardiovascular health-promoting properties, with notoginsenoside (NG)-R1 being a key active compound. Insulin resistance represents a global health concern associated with various metabolic disorders. This study investigated the effects of NG-R1 on palmitic acid (PA)-induced insulin resistance and oxidative stress in human umbilical vein endothelial cells (HUVECs). Our findings demonstrate that NG-R1 significantly alleviated impaired glucose uptake, enhanced the phosphorylation of protein kinase B (PKB/Akt) at Ser473, and reduced the phosphorylation of insulin receptor substrate 1 (IRS-1) at Ser307 in PA-treated HUVECs. Furthermore, NG-R1 treatment significantly lowered the levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), while increasing the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG). Additionally, NG-R1 activated the Nrf2/ARE signaling pathway, leading to a substantial increase in the expression of antioxidant enzymes. Notably, knockdown of Nrf2 attenuated the beneficial effects of NG-R1 on PA-induced insulin resistance and oxidative stress in HUVECs, suggesting that NG-R1 exerts its effects through the Nrf2/ARE pathway. In summary, our study reveals that NG-R1 ameliorated PA-induced insulin resistance in HUVECs via Nrf2/ARE pathway, providing novel insights into its potential for alleviating metabolic disorders and cardiovascular disease.

Therapeutic application of natural products: NAD+ metabolism as potential target

BACKGROUND

Nicotinamide adenine dinucleotide (NAD⁺) metabolism is involved in the entire physiopathological process and is critical to human health. Long-term imbalance in NAD⁺ homeostasis is associated with various diseases, including non-alcoholic fatty liver disease, diabetes mellitus, cardiovascular diseases, neurodegenerative disorders, aging, and cancer, making it a potential target for effective therapeutic strategies. Currently, several natural products that target NAD⁺ metabolism have been widely reported to have significant therapeutic effects, but systematic summaries are lacking.

PURPOSE

To summarize the latest findings on the prevention and treatment of various diseases through the regulation of NAD⁺ metabolism by various natural products in vivo and in vitro models, and evaluate the toxicities of the natural products.

METHODS

PubMed, Web of Science, and ScienceDirect were searched using the keywords "natural products sources," "toxicology," "NAD⁺ clinical trials," and "NAD⁺," and/or paired with "natural products" and "diseases" for studies published within the last decade until January 2023.

RESULTS

We found that the natural products mainly include phenols (curcumin, cyclocurcumin, 4-hydroxybenzyl alcohol, salvianolic acid B, pterostilbene, EGCG), flavonoids (pinostrobin, apigenin, acacetin, tilianin, kaempferol, quercetin, isoliquiritigenin, luteolin, silybin, hydroxysafflor yellow A, scutellarin), glycosides (salidroside), quinones (emodin, embelin, β-LAPachone, shikonin), terpenoids (notoginsenoside R1, ginsenoside F2, ginsenoside Rd, ginsenoside Rb1, ginsenoside Rg3, thymoquinone, genipin), pyrazines (tetramethylpyrazine), alkaloids (evodiamine, berberine), and phenylpropanoids (ferulic acid). These natural products have antioxidant, energy-producing, anti-inflammatory, anti-apoptotic and anti-aging effects, which mainly influence the NAMPT/NAD⁺/SIRT, AMPK/SIRT1/PGC-1α, Nrf2/HO-1, PKCs/PARPs/NF-κB, and AMPK/Nrf2/mTOR signaling pathways, thereby regulating NAD⁺ metabolism to prevent and treat various diseases. These natural products have been shown to be safe, tolerable and have fewer adverse effects in various in vivo and in vitro studies and clinical trials.

CONCLUSION

We evaluated the toxic effects of natural products and summarized the available clinical trials on NAD⁺ metabolism, as well as the recent advances in the therapeutic application of natural products targeting NAD⁺ metabolism, with the aim to provide new insights into the treatment of multiple disorders.

Excessive neutrophil extracellular trap formation induced by Porphyromonas gingivalis lipopolysaccharide exacerbates inflammatory responses in high glucose microenvironment

Introduction

Neutrophil extracellular trap (NET) is a novel defense strategy of neutrophils and found to be induced by Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) or high glucose. The aim of this study was to investigate the roles and mechanisms of NET formation in high glucose inflammatory microenvironment.

Methods

NETs induced by 1 μg/ml P. gingivalis LPS and/or 25 mM glucose were visualized using a fluorescence microscopy and the levels of extracellular DNA were determined by a microplate reader. The bactericidal efficiency of NETs was assessed by quantifying the survival P. gingivalis in neutrophils. The levels of NLRP3 and IL-1β in THP-1 derived-macrophages, and the expressions of p-PKC βII, p-MEK1/2, p-ERK1/2, ORAI1 and ORAI2 in neutrophils were detected by Western blot. Moreover, levels of intracellular Ca2+ and reactive oxygen species (ROS) in neutrophils were explored by flow cytometry.

Results

P. gingivalis LPS enhanced the formation of NETs and increased the levels of extracellular DNA in high glucose microenvironment (p < 0.05). Compared with normal glucose inflammatory microenvironment, quantities of extra- and intracellular viable P. gingivalis in neutrophils exposed to NETs induced in high glucose inflammatory one were increased (p < 0.05) and the expressions of NLRP3 and IL-1β were dramatically increased in macrophages co-cultured with NETs from high glucose inflammatory microenvironment (p < 0.05). In addition, levels of ROS, intracellular Ca²⁺, p-PKC βII, p-MEK1/2, p-ERK1/2, ORAI1 and ORAI2 were increased in neutrophils stimulated with both high glucose and P. gingivalis LPS compared with the single stimulus groups (p < 0.05).

Discussion

In high glucose inflammatory microenvironment, formation of NETs was enhanced via oxidative stress, which failed to reverse the decreased bactericidal capacity in high glucose microenvironment, and instead aggravated the subsequent inflammatory responses.

Ginsenoside Rb1 from Panax ginseng attenuates monoiodoacetate-induced osteoarthritis by inhibiting miR-21-5p/FGF18-mediated inflammation

Ginsenoside Rb1 (Rb1) is a major active compound in Panax ginseng and has shown considerable anti-inflammation effects. Osteoarthritis (OA) is one of the major degenerative disorders affecting the knee. MiR-21-5p is a potential therapeutic target for OA treatment. This study explored the anti-OA effects of Rb1 by focusing on its interaction with the miR-21-5p/FGF18 axis. OA was induced in rats using monoiodoacetate (MIA) and managed with Rb1. Then, changes in the histological structure and miR-21-5p-mediated signaling pathway were measured in joint tissues. The role of miR-21-5p/FGF18 in the anti-OA effects of Rb1 was confirmed by inducing its levels in rats and chondrocytes. Rb1 improved the histological structure and suppressed the production of cytokines in joint tissues. At the molecular level, Rb1 down-regulated miR-12-5p levels and up-regulated FGF18 levels. In chondrocytes, Rb1 increased cell viability, suppressed inflammation, down-regulated miR-21-5p levels, and up-regulated FGF18 levels. The restored level of miR-21-5p compromised the anti-OA effects of Rb1. In a nutshell, our study reported that the anti-OA effects of Rb1 relied on the inhibited expression of miR-21-5p. PRACTICAL APPLICATIONS: Ginsenoside Rb1 (Rb1) is a major active compound in Panax ginseng and has shown considerable anti-osteoarthritis (OA) effects. The current study not only relates the anti-OA function of ginsenoside Rb1 with microRNA but also provides valuable information for exploring novel targets for the development the anti-OA strategies.

Protective effects of the notoginsenoside R1 on acute lung injury by regulating the miR-128-2-5p/Tollip signaling pathway in rats with severe acute pancreatitis

Notoginsenoside R1 (NG-R1), the extract and the main ingredient of Panax notoginseng, has anti-inflammatory effects and can be used in treating acute lung injury (ALI). In this study, we explored the pulmonary protective effect and the underlying mechanism of the NG-R1 on rats with ALI induced by severe acute pancreatitis (SAP). MiR-128-2-5p, ERK1, Tollip, HMGB1, TLR4, IκB, and NF-κB mRNA expression levels were measured using real-time qPCR, and TLR4, Tollip, HMGB1, IRAK1, MyD88, ERK1, NF-κB65, and P-IκB-α protein expression levels using Western blot. The NF-κB and the TLR4 activities were determined using immunohistochemistry, and TNF-α, IL-6, IL-1β, and ICAM-1 levels in the bronchoalveolar lavage fluid (BALF) using ELISA. Lung histopathological changes were observed in each group. NG-R1 treatment reduced miR-128-2-5p expression in the lung tissue, increased Tollip expression, inhibited HMGB1, TLR4, TRAF6, IRAK1, MyD88, NF-κB65, and p-IκB-α expression levels, suppressed NF-κB65 and the TLR4 expression levels, reduced MPO activity, reduced TNF-α, IL-1β, IL-6, and ICAM-1 levels in BALF, and alleviated SAP-induced ALI. NG-R1 can attenuate SAP-induced ALI. The mechanism of action may be due to a decreased expression of miR-128-2-5p, increased activity of the Tollip signaling pathway, decreased activity of HMGB1/TLR4 and ERK1 signaling pathways, and decreased inflammatory response to SAP-induced ALI. Tollip was the regulatory target of miR-128-2-5p.

Identification and validation of hub genes for diabetic retinopathy

Background

Diabetic retinopathy (DR) is characterized by a gradually progressive alteration in the retinal microvasculature that leads to middle-aged adult acquired persistent blindness. Limited research has been conducted on DR pathogenesis at the gene level. Thus, we aimed to reveal novel key genes that might be associated with DR formation via a bioinformatics analysis.

Methods

The GSE53257 dataset from the Gene Expression Omnibus was downloaded for gene co-expression analysis. We identified significant gene modules via the Weighted Gene Co-expression Network Analysis, which was conducted by the Protein-Protein Interaction (PPI) Network via Cytoscape and from this we screened for key genes and gene sets for particular functional and pathway-specific enrichments. The hub gene expression was verified by real-time PCR in DR rats modeling and an external database.

Results

Two significant gene modules were identified. Significant key genes were predominantly associated with mitochondrial function, fatty acid oxidation and oxidative stress. Among all key genes analyzed, six up-regulated genes (i.e., SLC25A33, NDUFS1, MRPS23, CYB5R1, MECR, and MRPL15) were highly and significantly relevant in the context of DR formation. The PCR results showed that SLC25A33 and NDUFS1 expression were increased in DR rats modeling group.

Conclusion

Gene co-expression network analysis highlights the importance of mitochondria and oxidative stress in the pathophysiology of DR. DR co-expressing gene module was constructed and key genes were identified, and both SLC25A33 and NDUFS1 may serve as potential biomarker and therapeutic target for DR.

Notoginsenoside R1 alleviates high glucose-induced inflammation and oxidative stress in HUVECs via upregulating miR-147a

Endothelial dysfunction in atherosclerotic cardiovascular diseases has become one of the main characteristics in patients with diabetes mellitus, which is usually caused by abnormal inflammation and oxidative stress response. Presently, we focused on the role of Notoginsenoside R1 (NR1), a major component isolated from Panax notoginseng, in endothelial dysfunction caused by high glucose (HG). Human umbilical vein endothelial cells (HUVECs) were treated with HG and then dealt with NR1. Cell counting kit-8 assay and 5-bromo-2'-dexoyuridine assay were conducted to examine cell proliferation and viability. Flow cytometry was used to measure apoptosis. The angiogenesis of HUVECs was determined by tube formation assay. Moreover, the expressions of miR-147a, inflammatory cytokines (TNF-α, IL-6, and IL-10) and oxidative stress markers malondialdehyde, superoxide dismutase, and glutathione peroxidase were measured. The protein levels of MyD88/TRAF6/NF-κB axis, Bax, Bcl2, and Caspase3 were detected by Western blot. Furthermore, gain and loss of functional assays of miR-147a were performed to verify the role of miR-147a in NR1-mediated effects. Our data confirmed that NR1 (at 10-40 μM) reduces HG-induced HUVECs proliferation and viability inhibition, mitigates apoptosis, and enhances tube formation ability. Meanwhile, NR1 inhibited oxidative stress and inflammatory response and blocked the activation of the MyD88/TRAF6/NF-κB pathway induced by HG. In addition, NR1 promoted the expression of miR-147a, which targeted MyD88. Overexpression of miR-147a markedly inactivated MyD88/TRAF6/NF-κB pathway, while the miR-147a inhibitors reversed NR1-mediated protective effect in HG-induced HUVECs through activating MyD88/TRAF6/NF-κB pathway. In conclusion, NR1 relieves HG-induced endothelial cell injury by downregulating the MyD88/TRAF6/NF-κB pathway via upregulating miR-147a.

Guan Xin Dan Shen formulation protects db/db mice against diabetic cardiomyopathy via activation of Nrf2 signaling

Guan Xin Dan Shen formulation (GXDSF) is a widely used treatment for the management of coronary heart disease in China and is composed of three primary components: Dalbergiae odoriferae Lignum, Salviae miltiorrhizae Radix et Rhizoma and Panax notoginseng Radix et Rhizoma. However, the potential use of GXDSF for the management of diabetic cardiomyopathy (DCM) has not been previously assessed. The present study aimed to assess the effects of GXDSF on DCM, as well as the underlying mechanism. In the present study, db/db mice were used. Following treatment with GXDSF for 10 weeks, fasting blood glucose, insulin sensitivity, serum lipid levels and cardiac enzyme levels were detected. Cardiac pathological alterations and cardiac function were assessed by performing hematoxylin and eosin staining and echocardiograms, respectively. TUNEL assays were conducted to assess cardiomyocyte apoptosis. Additionally, reverse transcription‑quantitative PCR and western blotting were performed to evaluate the expression of apoptosis‑associated genes and proteins, respectively. In the model group, the db/db mice displayed obesity, hyperlipidemia and hyperglycemia, accompanied by noticeable myocardial hypertrophy and diastolic dysfunction. Following treatment with GXDSF for 10 weeks, serum triglyceride levels were lower and insulin sensitivity was enhanced in db/db mice compared with the model group, which indicated improvement in condition. Cardiac hypertrophy and dysfunction were also improved in db/db mice following treatment with GXDSF, resulting in significantly increased left ventricular ejection fraction and fractional shortening compared with the model group. Following treatment with metformin or GXDSF, model‑induced increases in levels of myocardial enzymes were decreased in the moderate and high dose groups. Moreover, the results indicated that, compared with the model group, GXDSF significantly inhibited cardiomyocyte apoptosis in diabetic heart tissues by increasing Bcl‑2 expression and decreasing the expression levels of Bax, cleaved caspase‑3 and cleaved caspase‑9. Mechanistically, GXDSF enhanced Akt phosphorylation, which upregulated antioxidant enzymes mediated by nuclear factor erythroid 2‑related factor 2 (Nrf2) signaling. Collectively, the results of the present study indicated that GXDSF attenuated cardiac dysfunction and inhibited cardiomyocyte apoptosis in diabetic mice via activation of Akt/Nrf2 signaling. Therefore, GXDSF may serve as a potential therapeutic agent for the management of DCM.

Notoginsenoside R1 protects boar sperm during liquid storage at 17°C

Reactive oxygen species (ROS) damage mammalian sperm during liquid storage. Notoginsenoside R1 (NR1) is a compound isolated from the roots of Panax notoginseng; it has powerful ROS-scavenging activities. This work hypothesized that the antioxidant capacity of NR1 could improve boar sperm quality and fertility during liquid storage. During liquid storage at 17°C, the supplementation of semen extender with NR1 (50 μM) significantly improved sperm motility, membrane integrity and acrosome integrity after 5 days of preservation. NR1 treatment also reduced ROS and lipid peroxidation (LPO) levels at day 5 (p <0.05). Higher glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) levels and sperm-zona pellucida binding capacity were observed in the 50 μM NR1 group than those in the control group at day 7 (p <0.05). Importantly, statistical analysis of the fertility of 200 sows indicated that addition of NR1 to the extender improved the fertility parameters of boar spermatozoa during liquid storage at 17°C (p <0.05). These results demonstrate the practical feasibility of using 50 μM NR1 as an antioxidant in boar extender during liquid storage at 17°C, which is beneficial to both spermatozoa quality and fertility.

Ginsenoside Re Attenuates High Glucose-Induced RF/6A Injury via Regulating PI3K/AKT Inhibited HIF-1α/VEGF Signaling Pathway

Hyperglycaemia-induced retinal microvascular endothelial cell apoptosis is a critical and principle event in diabetic retinopathy (DR), which involves a series of complex processes such as mitochondrial dysfunction and oxidative stress. Ginsenoside Re (Re), a key ingredients of ginseng, is considered to have various pharmacologic functions, such as antioxidative, inhibition of inflammation and anti-apoptotic properties. However, the effects of Re in DR and the related mechanisms of endothelial cell injury induced by high glucose (HG) exposure remain unclear. The present study was designed to investigate and evaluate the ability of Re to ameliorate HG-induced retinal endothelial RF/6A cell injury and the potential mechanisms involved in the hypoxia-inducible factor-1-alpha (HIF-1α)/vascular endothelial growth factor (VEGF) signaling regulated by phosphoinositide 3-kinase (PI3K)/AKT pathway. Our results showed that preincubation with Re exerted cytoprotective effects by reversing the HG-induced decrease in RF/6A cell viability, downregulation of apoptosis rate and inhibition of oxidative-related enzymes, thereby reducing the excess intracellular reactive oxygen species (ROS) and HG-triggered RF/6A cell injury. In addition, Western blot analysis results showed ginsenoside Re significantly increased HIF-1α expression in the cytoplasm but decreased its expression in the nucleus, suggesting that it reduced the translocation of HIF-1α from the cytoplasm to the nucleus, and downregulated VEGF level. Moreover, this effect is involved in the activation of the PI3K/Akt pathway. LY294002, a PI3K inhibitor, was used to block the Akt pathway. Afterwards, the effects of Re on the regulation of apoptotic related proteins, VEGF and HIF-1α nuclear transcription was partially reversed. These findings suggested the exerting protective effects of ginsenoside Re were associated with regulating of PI3K/AKT and HIF-1α/VEGF signaling pathway, which indicates that ginsenoside Re may ameliorates HG-induced retinal angiogenesis and suggests the potential for the development of Re as a therapeutic for DR.

NADPH oxidase: A membrane-bound enzyme and its inhibitors in diabetic complications

The human body has a mechanism for balancing the generation and neutralization of reactive oxygen species. The body is exposed to many agents that are responsible for the generation of reactive oxygen/nitrogen species, which leads to disruption of the balance between generation of these species and oxidative stress defence mechanisms. Diabetes is a chronic pathological condition associated with prolonged hyperglycaemia. Prolonged elevation of level of glucose in the blood leads to the generation of reactive oxygen species. This generation of reactive oxygen species is responsible for the development of diabetic vasculopathy, which includes micro- and macrovascular diabetic complications. Nicotinamide adenine dinucleotide phosphate oxidase (NOX) is a membrane-bound enzyme responsible for the development of reactive oxygen species in hyperglycaemia. Phosphorylation of the cytosolic components of NOX, such as p47phox, p67phox, and RAC-1, in hyperglycaemia is one of the important causes of conversion of oxygen to reactive oxygen. Overexpression of NOX in pathological conditions is associated with activation of aldose reductase, advanced glycation end products, protein kinase C and the hexosamine pathway. In addition, NOX also promotes the activation of inflammatory cytokines, such as TGF-β, TNF-α, NF-kβ, IL-6, and IL-18, the activation of endothelial growth factors, such as VEGF and FGF, hyperlipidaemia, and the deposition of collagen. Thus, overexpression of NOX is linked to the development of diabetic complications. The present review focuses on the role of NOX, its associated pathways, and various NOX inhibitors in the management and treatment of diabetic complications, such as diabetic nephropathy, retinopathy, neuropathy and cardiomyopathy.

Network Pharmacology-based Investigation of the Underlying Mechanism of Panax notoginseng Treatment of Diabetic Retinopathy

Background: Panax notoginseng, a Chinese herbal medicine, has been widely used to treat vascular diseases. Diabetic retinopathy (DR) is one of the complications of diabetic microangiopathy. According to recent studies, the application of Panax notoginseng extract and related Chinese patent medicine preparations can significantly improve DR. However, the pharmacological mechanisms remain unclear. Therefore, the purpose of this study was to decipher the potential mechanism of Panax notoginseng treatment of DR using network pharmacology.

Method: We evaluated and screened the active compounds of Panax notoginseng using the Traditional Chinese Medicine Systems Pharmacology database and collected potential targets of the compounds by target fishing. A multi-source database was also used to organize targets of DR. The potential targets as the treatment of DR with Panax notoginseng were then obtained by matching the compound targets with the DR targets. Using protein-protein interaction networks and topological analysis, interactions between potential targets were identified. In addition, we also performed gene ontology-biological process and pathway enrichment analysis for the potential targets by using the Biological Information Annotation Database.

Results: Eight active ingredients of Panax notoginseng and 31 potential targets for the treatment of DR were identified. The screening and enrichment analysis revealed that the treatment of DR using Panax notoginseng primarily involved 28 biological processes and 10 related pathways. Further analyses indicated that angiogenesis, inflammatory reactions, and apoptosis may be the main processes involved in the treatment of DR with Panax notoginseng. In addition, we determined that the mechanism of intervention of Panax notoginseng in treating DR may involve five core targets, VEGFA, MMP-9, MMP-2, FGF2, and COX-2.

Conclusion: Panax notoginseng may treat diabetic retinopathy through the mechanism of network pharmacological analysis. The underlying molecular mechanisms were closely related to the intervention of angiogenesis, inflammation, and apoptosis with VEGFA, MMP-9, MMP-2, FGF2, and COX-2 being possible targets.

Ginsenoside Rg1 prevents early diabetic retinopathy via reducing retinal ganglion cell layer and inner nuclear layer cell apoptosis in db/db mice

Background

Diabetic retinopathy (DR), a diabetic vascular complication, is prone to developing into blindness. Ginsenoside Rg1 (GRg1), a major saponin in ginseng, exerts high anti-apoptotic activity.

Methods

This study aimed to explore the protective effects of GRg1 against diabetes-induced retinal damage. Measurements of blood glucose, blood lipids and vascular permeability were performed, as well as assessments of pathological changes, and the retinal thickness of each layer. Retinal cell apoptosis related protein expression levels were measured by immunofluorescence and western blot assays.

Results

Our data demonstrated that GRg1 effectively reduced blood glucose and triglyceride levels and maintained normal retinal permeability and physiological structure. GRg1 maintained the thickness of the ganglion cell layer (GCL) and the inner nuclear layer (INL) by reducing cell apoptosis.

Conclusions

These data strongly indicate that GRg1 prevents diabetic retinal changes by decreasing GCL and INL cell apoptosis. GRg1 may be a promising drug for early DR treatment.

Ginseng for an eye: effects of ginseng on ocular diseases

The sense of vision is the primary means by which we gather information from our surroundings, and vision loss, therefore, severely compromises the life of the affected individuals, their families, and society. Loss of vision becomes more frequent with age, and diabetic retinopathy, age-related macular degeneration, cataracts, and glaucoma are the major causes of vision impairment. To find active pharmacological compounds that might prevent or ameliorate the vision-threatening eye diseases, numerous studies have been performed, and some botanical compounds, including those extracted from ginseng, have been shown to possess beneficial effects in the treatment or prevention of common ocular diseases. In this review, we summarize the recent reports investigating the therapeutic effects of ginseng and ginsenosides on diverse ocular diseases and discuss their therapeutic potential.

Focus on Notoginsenoside R1 in Metabolism and Prevention Against Human Diseases

Notoginsenoside (NG)-R1 is one of the main bioactive compounds from Panax notoginseng (PN) root, which is well known in the prescription for mediating the micro-circulatory hemostasis in human. In this article, we mainly discuss NG-R1 in metabolism and the biological activities, including cardiovascular protection, neuro-protection, anti-diabetes, liver protection, gastrointestinal protection, lung protection, bone metabolism regulation, renal protection, and anti-cancer. The metabolites produced by deglycosylation of NG-R1 exhibit higher permeability and bioavailability. It has been extensively verified that NG-R1 may ameliorate ischemia-reperfusion (IR)-induced injury in cardiovascular and neuronal systems mainly by upregulating the activity of estrogen receptor α-dependent phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) and nuclear factor erythroid-2-related factor 2 (NRF2) pathways and downregulating nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. However, no specific targets for NG-R1 have been identified. Expectedly, NG-R1 has been used as a main bioactive compound in many Traditional Chinese Medicines clinically, such as Xuesaitong, Naodesheng, XueShuanTong, ShenMai, and QSYQ. These suggest that NG-R1 exhibits a significant potency in drug development.

Ginsenosides Rb1 and Rg1 Protect Primary Cultured Astrocytes against Oxygen-Glucose Deprivation/Reoxygenation-Induced Injury via Improving Mitochondrial Function

This study aimed to evaluate whether ginsenosides Rb1 (20-S-protopanaxadiol aglycon) and Rg1 (20-S-protopanaxatriol aglycon) have mitochondrial protective effects against oxygen-glucose deprivation/reoxygenation (OGD/R)-induced injury in primary mouse astrocytes and to explore the mechanisms involved. The OGD/R model was used to mimic the pathological process of cerebral ischemia-reperfusion in vitro. Astrocytes were treated with normal conditions, OGD/R, OGD/R plus Rb1, or OGD/R plus Rg1. Cell viability was measured to evaluate the cytotoxicity of Rb1 and Rg1. Intracellular reactive oxygen species (ROS) and catalase (CAT) were detected to evaluate oxidative stress. The mitochondrial DNA (mtDNA) copy number and mitochondrial membrane potential (MMP) were measured to evaluate mitochondrial function. The activities of the mitochondrial respiratory chain (MRC) complexes I–V and the level of cellular adenosine triphosphate (ATP) were measured to evaluate oxidative phosphorylation (OXPHOS) levels. Cell viability was significantly decreased in the OGD/R group compared to the control group. Rb1 or Rg1 administration significantly increased cell viability. Moreover, OGD/R caused a significant increase in ROS formation and, subsequently, it decreased the activity of CAT and the mtDNA copy number. At the same time, treatment with OGD/R depolarized the MMP in the astrocytes. Rb1 or Rg1 administration reduced ROS production, increased CAT activity, elevated the mtDNA content, and attenuated the MMP depolarization. In addition, Rb1 or Rg1 administration increased the activities of complexes I, II, III, and V and elevated the level of ATP, compared to those in the OGD/R groups. Rb1 and Rg1 have different chemical structures, but exert similar protective effects against astrocyte damage induced by OGD/R. The mechanism may be related to improved efficiency of mitochondrial oxidative phosphorylation and the reduction in ROS production in cultured astrocytes.

Ginsenoside Rb1 Attenuates High Glucose-Induced Oxidative Injury via the NAD-PARP-SIRT Axis in Rat Retinal Capillary Endothelial Cells

(1) Aims: The present study aimed to observe the effects of Ginsenoside Rb1 on high glucose-induced endothelial damage in rat retinal capillary endothelial cells (RCECs) and to investigate the underlying mechanism. (2) Methods: Cultured RCECs were treated with normal glucose (5.5 mM), high glucose (30 mM glucose), or high glucose plus Rb1 (20 μM). Cell viability, lactate dehydrogenase (LDH) levels, the mitochondrial DNA copy number, and the intracellular ROS content were measured to evaluate the cytotoxicity. Superoxide dismutase (SOD), catalase (CAT), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX), poly(ADP-ribose) polymerase (PARP), and sirtuin (SIRT) activity was studied in cell extracts. Nicotinamide adenine dinucleotide (NAD⁺)/NADH, NADPH/NADP⁺, and glutathione (GSH)/GSSG levels were measured to evaluate the redox state. The expression of nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1), SIRT1, and SIRT3 was also evaluated after Rb1 treatment. (3) Results: Treatment with Rb1 significantly increased the cell viability and mtDNA copy number, and inhibited ROS generation. Rb1 treatment increased the activity of SOD and CAT and reduced the activity of NOX and PARP. Moreover, Rb1 enhanced both SIRT activity and SIRT1/SIRT3 expression. Additionally, Rb1 was able to re-establish the cellular redox balance in RCECs. However, Rb1 showed no effect on NMNAT1 expression in RCECs exposed to high glucose. (4) Conclusion: Under high glucose conditions, decreases in the reducing power may be linked to DNA oxidative damage and apoptosis via activation of the NMNAT-NAD-PARP-SIRT axis. Rb1 provides an advantage during high glucose-induced cell damage by targeting the NAD-PARP-SIRT signaling pathway and modulating the redox state in RCECs.

A simplified herbal formula for the treatment of heart failure: Efficacy, bioactive ingredients, and mechanisms

Heart failure (HF) is a complex pathology for which single-agent therapy cannot provide comprehensive efficacy. Therefore, effective combination therapies for HF are increasingly emphasized. Multiple-component drugs derived from Chinese herbal formulae provide efficacy and safety when administered to patients with HF. Nuanxinkang (NXK) is a simplified Chinese herbal formula which has been widely applied in HF for decades. It exhibits comprehensive cardiac protective effects in HF patients as an adjuvant therapy, including improving heart function and quality-of-life, reducing inflammation, and regulating neurohormones. Nevertheless, the bioactive ingredients and mechanisms of action of NXK are unknown, which hinders its further application. Here, we examined the therapeutic efficacy of NXK in a mouse model of HF. Using transcriptome analysis and drug similarity analysis we found that NXK inhibits apoptosis and inflammation, while improving cardiac contraction and reversing myocardial fibrosis. In addition, we detected 21 bioactive species in NXK using UHPLC-MS analysis. Based on these data, we performed network pharmacology analysis to investigate ingredient-target-pathway interactions. We further confirmed 13 genes as potential targets, and assessed the effects of NXK on the AKT to validate the anti-apoptotic role of NXK both in vivo and in vitro. Thus, our work has identified a simplified herbal formula with efficacy against HF by exploring its constituents and mechanism of action, providing evidence for an innovative treatment strategy and novel therapeutic targets for HF.

[Effects of Panax notoginseng saponins on liver graft rejection in rats and the mechanisms]

OBJECTIVE

To investigate the effects of Panax notoginseng saponins (PNS) on the functional status of Kupffer cells (KCs) and immune environment after liver transplantation and explore the possible mechanisms.

METHODS

KCs were isolated from rats and assessed for phagocytic activity and viability using ink and Trypan blue staining. The cells were exposed to lipopolysaccharide (LPS) alone or in combination with PNS treatment at 0, 10 or 20 μmol/L. The expressions of the inflammatory factors and the oxidative stress products in the cells and the supernatant were assayed with Western blotting and ELISA; the expression of CD206 was detected using immunofluorescence assay, and the expressions of NF-κB and Keap1-Nrf2-ARE pathway proteins were detected using Western blotting. We established an orthotopic liver transplantation (LT) model in rats and assessed the effect of 200 mg/kg PNS on the graft function, inflammatory factors, pathology of the liver tissue, hepatocyte apoptosis and survival time of the rats in comparison with those in rats receiving a sham operation or PBS treatment following LT.

RESULTS

Treatment with PNS significantly lowered the levels of inflammatory factors and oxidative stress products and increased the levels of interleukin-10 (IL-10) and SOD in a concentration-dependent manner in the KCs (P < 0.05). Immunofluorescence assay showed that PNS treatment obviously increased the expression of CD206 in the KCs. PNS treatment also significantly reduced the expressions of IRAK4, p-IKKα, p-IκBα, p-p65 and Keap1 proteins and increased the expression levels of Nrf2 and ARE proteins in the KCs (P < 0.05). In the rat models of LT, PNS treatment significantly improved the liver graft function, lowered the expression of the pro-inflammatory factors, and reduced hepatocyte apoptosis as compared with PBS treatment. PNS treatment obviously alleviated pathological changes in the liver graft and significantly prolonged the survival time of the rats following LT (P < 0.05). In addition, injection of GdCl3 to block KC function resulted in severe acute graft rejection in the rats regardless of PNS treatment (P > 0.05).

CONCLUSIONS

PNS can reduce inflammatory response and oxidative stress in activated KCs by inhibiting NF-κB and Keap1-Nrf2-ARE pathways and promote the polarization of KCs into M2 phenotype to prolong the survival time of rats after LT.

Diabetic retinopathy: Focus on NADPH oxidase and its potential as therapeutic target

Diabetic retinopathy is a common complication of diabetes that affects the retina due to a sustained high blood sugar level. Recent studies have demonstrated that high glucose-driven oxidative stress plays an important role in the microvascular complications of retina in diabetes. Oxidative stress occurs due to the excess of reactive oxygen species, which causes oxidative damage to retina, leading to the leak of tiny blood vessels, or acts as signaling molecules to trigger neovascularization, resulting in new fragile vessels. NADPH oxidase (NOX) is a key enzymatic source of reactive oxygen species in the retina, and it is involved in the early as well as the advanced stage of diabetic retinopathy. To date, at least 7 NOX isoforms, including NOX1 to NOX5, dual oxidase1 and dual oxidase 2, have been identified. It has been shown that NOX isoforms exert different roles in the pathogenesis of diabetic retinopathy. Intervention of NOX by its inhibitors or modulators shows beneficial effect on improving the retinal functions in the models of diabetic retinopathy in vivo or in vitro. Thereby, NOX might be a potential target for the therapy of diabetic retinopathy. The present review focuses on the role of NOX, particularly the NOX isoforms, in promoting the development of diabetic retinopathy. In addition, NOX isoforms as potential targets for therapy of diabetic retinopathy are also discussed.

Nutraceuticals for the Treatment of Diabetic Retinopathy

Diabetic retinopathy (DR) is one of the most common complications of diabetes mellitus and is characterized by degeneration of retinal neurons and neoangiogenesis, causing a severe threat to vision. Nowadays, the principal treatment options for DR are laser photocoagulation, vitreoretinal surgery, or intravitreal injection of drugs targeting vascular endothelial growth factor. However, these treatments only act at advanced stages of DR, have short term efficacy, and cause side effects. Treatment with nutraceuticals (foods providing medical or health benefits) at early stages of DR may represent a reasonable alternative to act upstream of the disease, preventing its progression. In particular, in vitro and in vivo studies have revealed that a variety of nutraceuticals have significant antioxidant and anti-inflammatory properties that may inhibit the early diabetes-driven molecular mechanisms that induce DR, reducing both the neural and vascular damage typical of DR. Although most studies are limited to animal models and there is the problem of low bioavailability for many nutraceuticals, the use of these compounds may represent a natural alternative method to standard DR treatments.

Ginseng for the treatment of diabetes and diabetes-related cardiovascular complications: a discussion of the evidence 1

Diabetes mellitus (DM) is a chronic metabolic disorder associated with elevated blood glucose levels due either to insufficient insulin production (type 1 DM) or to insulin resistance (type 2 DM). The incidence of DM around the world continues to rise dramatically with more than 400 million cases reported today. Among the most serious consequences of chronic DM are cardiovascular complications that can have deleterious effects. Although numerous treatment options are available, including both pharmacological and nonpharmacological, there is substantial emerging interest in the use of traditional medicines for the treatment of this condition and its complications. Among these is ginseng, a medicinal herb that belongs to the genus Panax and has been used for thousands of years as a medicinal agent especially in Asian cultures. There is emerging evidence from both animal and clinical studies that ginseng, ginseng constituents including ginsenosides, and ginseng-containing formulations can produce beneficial effects in terms of normalization of blood glucose levels and attenuation of cardiovascular complications through a multiplicity of mechanisms. Although more research is required, ginseng may offer a useful therapy for the treatment of diabetes as well as its complications.