Polydatin Restores Endothelium-Dependent Relaxation in Rat Aorta Rings Impaired by High Glucose: A Novel Insight into the PPARβ-NO Signaling Pathway

Natural products in atherosclerosis therapy by targeting PPARs: a review focusing on lipid metabolism and inflammation

Inflammation and dyslipidemia are critical inducing factors of atherosclerosis. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors and control the expression of multiple genes that are involved in lipid metabolism and inflammatory responses. However, synthesized PPAR agonists exhibit contrary therapeutic effects and various side effects in atherosclerosis therapy. Natural products are structural diversity and have a good safety. Recent studies find that natural herbs and compounds exhibit attractive therapeutic effects on atherosclerosis by alleviating hyperlipidemia and inflammation through modulation of PPARs. Importantly, the preparation of natural products generally causes significantly lower environmental pollution compared to that of synthesized chemical compounds. Therefore, it is interesting to discover novel PPAR modulator and develop alternative strategies for atherosclerosis therapy based on natural herbs and compounds. This article reviews recent findings, mainly from the year of 2020 to present, about the roles of natural herbs and compounds in regulation of PPARs and their therapeutic effects on atherosclerosis. This article provides alternative strategies and theoretical basis for atherosclerosis therapy using natural herbs and compounds by targeting PPARs, and offers valuable information for researchers that are interested in developing novel PPAR modulators.

Preclinical toxicological assessment of polydatin in zebrafish model

Polydatin (3,4',5-trihydroxystilbene-3-β-D-glucoside, piceid), a natural stilbenoid found in different plant sources, has gained increasing attention for its potential health benefits. However, prior to its widespread adoption in human therapeutics and consumer products, a comprehensive investigation of its toxicological effects is crucial. In this study, the toxicity of polydatin was investigated in a developmental toxicity test using zebrafish (Danio rerio) as a valuable model for preclinical assessments. We employed the Fish Embryo Test (FET test - OECD n°236) to investigate the effects of polydatin on survival, hatchability, development, and behavior of zebrafish embryo-larval stage. Remarkably, the results demonstrated that polydatin up to 435 μM showed no toxicity. Throughout the exposure period, zebrafish embryos exposed to polydatin exhibited normal development, with no significant mortality observed. Furthermore, hatching success and heartbeat rate were unaffected, and no morphological abnormalities were identified, signifying a lack of teratogenic effects and cardiotoxicity. Locomotion activity assessment revealed normal swimming patterns and response to stimuli, indicating no neurotoxic effects. Our study provides valuable insights into the toxicological profile of polydatin, suggesting that it may offer potential therapeutic benefits under a considerable concentration range. In addition, zebrafish model proves to be an efficient system for early-stage toxicological screening, guiding further investigations into the secure utilization of polydatin for human health and wellness.

Advances for pharmacological activities of Polygonum cuspidatum - A review

CONTEXT

Polygonum cuspidatum Sieb. et Zucc (Polygonaceae), the root of which is included in the Chinese Pharmcopoeia under the name 'Huzhang', has a long history as a medicinal plant and vegetable. Polygonum cuspidatum has been used in traditional Chinese medicine for the treatment of inflammation, hyperlipemia, etc.

OBJECTIVE

This article reviews the pharmacological action and the clinical applications of Polygonum cuspidatum and its extracts, whether in vivo or in vitro. We also summarized the main phytochemical constituents and pharmacokinetics of Polygonum cuspidatum and its extracts.

METHODS

The data were retrieved from major medical databases, such as CNKI, PubMed, and SinoMed, from 2014 to 2022. Polygonum cuspidatum, pharmacology, toxicity, clinical application, and pharmacokinetics were used as keywords.

RESULTS

The rhizomes, leaves, and flowers of Polygonum cuspidatum have different phytochemical constituents. The plant contains flavonoids, anthraquinones, and stilbenes. Polygonum cuspidatum and the extracts have anti-inflammatory, antioxidation, anticancer, heart protection, and other pharmacological effects. It is used in the clinics to treat dizziness, headaches, traumatic injuries, and water and fire burns.

CONCLUSIONS

Polygonum cuspidatum has the potential to treat many diseases, such as arthritis, ulcerative colitis, asthma, and cardiac hypertrophy. It has a broad range of medicinal applications, but mainly focused on root medication; its aerial parts should receive more attention. Pharmacokinetics also need to be further investigated.

Polydatin improves vascular endothelial function by maintaining mitochondrial homeostasis under high glucose conditions

Previous studies have shown that polydatin (Poly) confer cardioprotective effects. However, its underlying mechanisms remain elusive. This study showed that Poly (10 µM) treatment reversed the high glucose (HG)-induced decrease in acetylcholine-elicited vasodilation in aortas. Poly also improved the acetylcholine-induced vasodilation of aortic vessels isolated from diabetic rats. Meanwhile, Poly ameliorated the morphological damage of the thoracic aorta and improved the viability of HUVECs under HG conditions. Furthermore, analysis of the vasoprotective effect of Poly under HG conditions by transmission electron microscopy, Western blotting, and qPCR revealed that Poly improved endothelial pyroptosis through the NLRP3/Caspase/1-IL-1β pathway, enhanced dynamin-related protein 1-mediated mitochondrial fission, and increased the mitochondrial membrane potential under HG conditions. In conclusion, Poly restored acetylcholine-induced vasodilation impaired by HG incubation, which was associated with reduced oxidation, inflammation, and pyroptosis, the recovery of the mitochondrial membrane potential and maintenance of mitochondrial dynamic homeostasis of endothelial cells in the aortas.

Polydatin: Pharmacological Mechanisms, Therapeutic Targets, Biological Activities, and Health Benefits

Polydatin is a natural potent stilbenoid polyphenol and a resveratrol derivative with improved bioavailability. Polydatin possesses potential biological activities predominantly through the modulation of pivotal signaling pathways involved in inflammation, oxidative stress, and apoptosis. Various imperative biological activities have been suggested for polydatin towards promising therapeutic effects, including anticancer, cardioprotective, anti-diabetic, gastroprotective, hepatoprotective, neuroprotective, anti-microbial, as well as health-promoting roles on the renal system, the respiratory system, rheumatoid diseases, the skeletal system, and women's health. In the present study, the therapeutic targets, biological activities, pharmacological mechanisms, and health benefits of polydatin are reviewed to provide new insights to researchers. The need to develop further clinical trials and novel delivery systems of polydatin is also considered to reveal new insights to researchers.

Impact of Phytochemicals on PPAR Receptors: Implications for Disease Treatments

Peroxisome proliferator-activated receptors (PPARs) are members of the ligand-dependent nuclear receptor family. PPARs have attracted wide attention as pharmacologic mediators to manage multiple diseases and their underlying signaling targets. They mediate a broad range of specific biological activities and multiple organ toxicity, including cellular differentiation, metabolic syndrome, cancer, atherosclerosis, neurodegeneration, cardiovascular diseases, and inflammation related to their up/downstream signaling pathways. Consequently, several types of selective PPAR ligands, such as fibrates and thiazolidinediones (TZDs), have been approved as their pharmacological agonists. Despite these advances, the use of PPAR agonists is known to cause adverse effects in various systems. Conversely, some naturally occurring PPAR agonists, including polyunsaturated fatty acids and natural endogenous PPAR agonists curcumin and resveratrol, have been introduced as safe agonists as a result of their clinical evidence or preclinical experiments. This review focuses on research on plant-derived active ingredients (natural phytochemicals) as potential safe and promising PPAR agonists. Moreover, it provides a comprehensive review and critique of the role of phytochemicals in PPARs-related diseases and provides an understanding of phytochemical-mediated PPAR-dependent and -independent cascades. The findings of this research will help to define the functions of phytochemicals as potent PPAR pharmacological agonists in underlying disease mechanisms and their related complications.

Polydatin: A Critical Promising Natural Agent for Liver Protection via Antioxidative Stress

Polydatin, one of the natural active small molecules, was commonly applied in protecting and treating liver disorders in preclinical studies. Oxidative stress plays vital roles in liver injury caused by various factors, such as alcohol, viral infections, dietary components, drugs, and other chemical reagents. It is reported that oxidative stress might be one of the main reasons in the progressive development of alcohol liver diseases (ALDs), nonalcoholic liver diseases (NAFLDs), liver injury, fibrosis, hepatic failure (HF), and hepatocellular carcinoma (HCC). In this paper, we comprehensively summarized the pharmacological effects and potential molecular mechanisms of polydatin for protecting and treating liver disorders via regulation of oxidative stress. According to the previous studies, polydatin is a versatile natural compound and exerts significantly protective and curative effects on oxidative stress-associated liver diseases via various molecular mechanisms, including amelioration of liver function and insulin resistance, inhibition of proinflammatory cytokines, lipid accumulation, endoplasmic reticulum stress and autophagy, regulation of PI3K/Akt/mTOR, and activation of hepatic stellate cells (HSCs), as well as increase of antioxidant enzymes (such as catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH), superoxide dismutase (SOD), glutathione reductase (GR), and heme oxygenase-1 (HO-1)). In addition, polydatin acts as a free radical scavenger against reactive oxygen species (ROS) by its phenolic and ethylenic bond structure. However, further clinical investigations are still needed to explore the comprehensive molecular mechanisms and confirm the clinical treatment effect of polydatin in liver diseases related to regulation of oxidative stress.

Old dog, new tricks: Polydatin as a multitarget agent for current diseases

Polydatin (PD) is a natural single-crystal product that is primarily extracted from the traditional plant Polygonum cuspidatum Sieb. et Zucc. Early research showed that PD exhibited a variety of biological activities. PD has attracted increasing research interest since 2014, but no review comprehensively summarized the new findings. A great gap between its biological activities and drug development remains. It is necessary to summarize new findings on the pharmacological effects of PD on current diseases. We propose that PD will most likely be used in cardiac and cerebral ischaemia/reperfusion-related diseases and atherosclerosis in the future. The present work classified these new findings according to diseases and summarized the main effects of PD via specific mechanisms of action. In summary, we found that PD played a therapeutic role in a variety of diseases, primarily via five mechanisms: antioxidative effects, antiinflammatory effects, regulation of autophagy and apoptosis, maintenance of mitochondrial function, and lipid regulation.

Novel polydatin-loaded chitosan nanoparticles for safe and efficient type 2 diabetes therapy: In silico, in vitro and in vivo approaches

Polydatin (PD) has many pharmacological activities; however, its bioavailability is still a critical cornerstone issue. The present investigation aimed to develop a novel oral formula of polydatin-loaded chitosan nanoparticles (PD-CSNPs) to improve PD therapeutic potential against type 2 diabetes. The interaction mechanism between PD and CSNPs was studied via Monte Carlo and molecular dynamics simulations. The formula was prepared and characterized by FTIR, XRD, TEM, and dynamic light scattering. The release profile of PD was studied in vitro, as well as the cytotoxicity effect versus Vero cell line and antidiabetic activity in type 2 diabetic rats were investigated. The practical results verified the formation of PD-CSNPs with entrapment efficiency of about 96.74 ± 0.39%, size average 144.25 ± 3.37 nm, and the prolonged release pattern was less than 20% after 12 hrs. The cytotoxicity study confirmed the safety of the formula at low and high doses. Moreover, the in vivo study revealed that PD-CSNPs exhibited highly significant antidiabetic efficacy in diabetic rats compared to free PD. To conclude, the current investigation proved that CSNPs are promising nanocarriers for nontoxic and effective PD delivery against type 2 diabetes.

PPARδ: A Potential Therapeutic Target for the Treatment of Metabolic Hypertension

High blood pressure and its associated cardiovascular diseases have been major risks for public health. Multiple metabolic risk factors can cause the vascular dysfunction and vascular lesion, and the hypertension due to metabolic disturbances was defined as metabolic hypertension. The members of a subfamily of the nuclear receptors, peroxisome proliferator-activated receptors (PPARs), were found to be key regulators of metabolism and vascular function. We provide up-to-date knowledge on the role of subtype PPARδ in the regulation of metabolism and vascular function and the effect of its intervention on the metabolic hypertension management. We hope to give some insights into the development of more effective treatments of metabolic hypertension and its main complications.

Effects of aerobic exercise on the expressions and activities of nitric oxide synthases in the blood vessel endothelium in prediabetes mellitus

Previous studies by our group have indicated that exercise intervention can ameliorate endothelial dysfunction, which is an early pathophysiological change of prediabetes mellitus. The present study aimed to test the hypothesis that nitric oxide synthases (NOSs), which are expressed in blood vessel endothelium, contribute to the mitigation of vascular endothelium-dependent dysfunction by aerobic exercise in prediabetes mellitus. A prediabetic rat model was established by feeding the rats an additional high-energy diet, and was confirmed by testing blood glucose levels, the area-under-the-curve for the blood glucose tests (P<0.05) and the changes to the histological morphology of the thoracic aorta. Further examination identified that NOS expression changed significantly between the control and prediabetes groups, indicating endothelial dysfunction in the prediabetic rats. Following aerobic exercise, a significant increase in NOS, endothelial (eNOS) mRNA and protein expression (P<0.05), and a significant decrease in NOS, inducible (iNOS) mRNA and protein expression (P<0.05) was identified in the prediabetic rats compared with the control group. No significant change in nitric oxide synthase, brain expression was observed in the prediabetic rat group compared with the control group. Notably, there was also a significant increase and decrease in eNOS and iNOS activity, respectively, in the prediabetes group compared with the control group (P<0.05). Furthermore, nitric oxide (NO) concentration in the vascular endothelium was detected, which revealed a significant increase in NO concentration in the prediabetic rats following aerobic exercise compared with the control (P<0.05). The present study provided results that demonstrated that aerobic exercise ameliorated the vascular endothelium-dependent dysfunction through the NOS/NO signaling pathway, which is primarily regulated by NOS expression and activity, in prediabetes mellitus. The current study provided the theoretical basis for the use of exercise intervention to prevent diabetes mellitus during the early stage.

Polydatin Prevents Methylglyoxal-Induced Apoptosis through Reducing Oxidative Stress and Improving Mitochondrial Function in Human Umbilical Vein Endothelial Cells

Methylglyoxal (MGO), an active metabolite of glucose, has been reported to induce vascular cell apoptosis in diabetic complication. Polydatin (PD), a small natural compound from Polygonum cuspidatum, has a number of biological functions, such as antioxidative, anti-inflammatory, and nephroprotective properties. However, the protective effects of PD on MGO-induced apoptosis in endothelial cells remain to be elucidated. In this study, human umbilical vein endothelial cells (HUVECs) were used to explore the effects of PD on MGO-induced cell apoptosis and the possible mechanism involved. HUVECs were pretreated with PD for 2 h, followed by stimulation with MGO. Then cell apoptosis, reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP) impairment, mitochondrial morphology alterations, and Akt phosphorylation were assessed. The results demonstrated that PD significantly prevented MGO-induced HUVEC apoptosis. PD pretreatment also significantly inhibited MGO-induced ROS production, MMP impairment, mitochondrial morphology changes, and Akt dephosphorylation. These results and the experiments involving N-acetyl cysteine (antioxidant), Cyclosporin A (mitochondrial protector), and LY294002 (Akt inhibitor) suggest that PD prevents MGO-induced HUVEC apoptosis, at least in part, through inhibiting oxidative stress, maintaining mitochondrial function, and activating Akt pathway. All of these data indicate the potential application of PD for the treatment of diabetic vascular complication.

Polydatin possesses notable anti‑osteoporotic activity via regulation of OPG, RANKL and β‑catenin

This study was designed to investigate the anti‑osteoporotic activity of polydatin and its possible underlying mechanism. Osteoporosis was induced in mice by ovariectomy (OVX) and the mice were divided into 5 groups: An OVX only group, polydatin groups (10, 20 and 40 mg/kg) and a sham group (n=10/group). After 12 weeks of treatment, body weight, uterine index and the dry weight of thigh‑bones were recorded. In addition, the serum calcium, serum phosphorus, alkaline phosphatase (ALP) and osteoprotegerin (OPG) levels were also determined. Western blot analysis was then conducted to investigate the possible mechanism underlying the effect of polydatin via determining the expression of OPG, receptor activators of nuclear factor‑κB ligand (RANKL) and β‑catenin in the ST2 cell line. The results indicated that intraperitoneal injection of polydatin (10, 20 and 40 mg/kg/day) decreased body weight, and increased uterine index and dry weights of thigh‑bones of ovariectomized mice (P<0.05), and polydatin also significantly increased the serum calcium, phosphorus, ALP and OPG of ovariectomized mice (P<0.05). Results of western blot analysis showed that polydatin upregulated the ratio of OPG/RANKL (P<0.05) and β‑catenin protein in ST2 cells. In conclusion, the results demonstrated that polydatin exhibits anti‑osteoporotic activity via regulating osteoprotegerin, RANKL and β‑catenin.

Polydatin ameliorates lipid and glucose metabolism in type 2 diabetes mellitus by downregulating proprotein convertase subtilisin/kexin type 9 (PCSK9)

BACKGROUND

Abnormalities in lipid and glucose metabolism are constantly observed in type 2 diabetes. However, these abnormalities can be ameliorated by polydatin. Considering the important role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in metabolic diseases, we explore the possible mechanism of polydatin on lipid and glucose metabolism through its effects on PCSK9.

METHODS

An insulin-resistant HepG2 cell model induced by palmitic acid (PA) and a db/db mice model were used to clarify the role of polydatin on lipid and glucose metabolism.

RESULTS

In insulin-resistant HepG2 cells, polydatin upregulated the protein levels of LDLR and GCK but repressed PCSK9 protein expression, besides, polydatin also inhibited the combination between PCSK9 and LDLR. Knockdown and overexpression experiments indicated that polydatin regulated LDLR and GCK expressions through PCSK9. In the db/db mice model, we found that polydatin markedly enhanced GCK and LDLR protein levels, and inhibited PCSK9 expression in the liver. Molecular docking assay was further performed to analyze the possible binding mode between polydatin and the PCSK9 crystal structure (PDB code: 2p4e), which indicated that steady hydrogen bonds formed between polydatin and PCSK9.

CONCLUSIONS

Our study indicates that polydatin ameliorates lipid and glucose metabolism in type 2 diabetes mellitus by downregulating PCSK9.