Lipid-lowering effects of polydatin from Polygonum cuspidatum in hyperlipidemic hamsters

Metabolic engineering and in vitro biosynthesis of phytochemicals and non-natural analogues

Over the years, natural products from plants and their non-natural derivatives have shown to be active against different types of chronic diseases. However, isolation of such natural products can be limited due to their low bioavailability, and environmental restrictions. To address these issues, in vivo and in vitro reconstruction of plant metabolic pathways and the metabolic engineering of microbes and plants have been used to generate libraries of compounds. Significant advances have been made through metabolic engineering of microbes and plant cells to generate a variety of compounds (e.g. isoprenoids, flavonoids, or stilbenes) using a diverse array of methods to optimize these processes (e.g. host selection, operational variables, precursor selection, gene modifications). These approaches have been used also to generate non-natural analogues with different bioactivities. In vitro biosynthesis allows the synthesis of intermediates as well as final products avoiding post-translational limitations. Moreover, this strategy allows the use of substrates and the production of metabolites that could be toxic for cells, or expand the biosynthesis into non-conventional media (e.g. organic solvents, supercritical fluids). A perspective is also provided on the challenges for generating novel chemical structures and the potential of combining metabolic engineering and in vitro biocatalysis to produce metabolites with more potent biological activities.

Botany, phytochemistry, pharmacology, and potential application of Polygonum cuspidatum Sieb.et Zucc.: a review

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonum cuspidatum Sieb. et Zucc. (Polygonum cuspidatum), also known as Reynoutria japonica Houtt and Huzhang in China, is a traditional and popular Chinese medicinal herb. Polygonum cuspidatum with a wide spectrum of pharmacological effects has been used for treatment of inflammation, favus, jaundice, scald, and hyperlipemia, etc.

AIM OF THE REVIEW

The present paper reviews the traditional applications as well as advances in botany, phytochemistry, pharmacodynamics, pharmacokinetics and toxicology of this plant. Finally, the tendency and perspective for future investigation of this plant are discussed, too.

MATERIALS AND METHODS

A systematic review of literature about Polygonum cuspidatum is carried out using resources including classic books about Chinese herbal medicine, and scientific databases including Pubmed, SciFinder, Scopus, the Web of Science and others.

RESULTS

Polygonum cuspidatum is widely distributed in the world and has been used as a traditional medicine for a long history in China. Over 67 compounds including quinones, stilbenes, flavonoids, counmarins and ligans have been isolated and identified from this plant. The root of this plant is used as the effective agent in pre-clinical and clinical practice for regulating lipids, anti-endotoxic shock, anti-infection and anti-inflammation, anti-cancer and other diseases in China and Japan.

CONCLUSION

As an important traditional Chinese medicine, Polygonum cuspidatum has been used for treatment of hyperlipemia, inflammation, infection and cancer, etc. Because there is no enough systemic data about the chemical constituents and their pharmacological effects or toxicities, it is important to investigate the pharmacological effects and molecular mechanisms of this plant based on modern realization of diseases' pathophysiology. Drug target-guided and bioactivity-guided isolation and purification of the chemical constituents from this plant and subsequent evaluation of their pharmacologic effects will promote the development of new drug and make sure which chemical constituent or multiple ingredients contributes its pharmacological effects. Additionally, chemicals and their pharmacological effects of the other parts such as the aerial part of this plant should be exploited in order to avoid resource waste and find new chemical constituents.

Protective effects of polydatin on septic lung injury in mice via upregulation of HO-1

The present study was carried out to investigate the effects and mechanisms of polydatin (PD) in septic mice. The model of cecal ligation and puncture (CLP-)induced sepsis was employed. Pretreatment of mice with PD (15, 45, and 100 mg/kg) dose-dependently reduced sepsis-induced mortality and lung injury, as indicated by alleviated lung pathological changes and infiltration of proteins and leukocytes. In addition, PD inhibited CLP-induced serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) production, lung cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase isoform (iNOS) protein expressions and NF-κB activation. Notably, PD upregulated the expression and activity of heme oxygenase (HO-)1 in lung tissue of septic mice. Further, the protective effects of PD on sepsis were abrogated by ZnPP IX, a specific HO-1 inhibitor. These findings indicated that PD might be an effective antisepsis drug.

DDDAS Design of Drug Interventions for the Treatment of Dyslipidemia in ApoE-/- Mice

Computational models of complex systems, such as signaling networks and biological systems, can be used to explain the behavior of such systems under various conditions. The large number of integrated processes and variables, and the nonlinearities inherent in the fundamental processes, make it difficult for scientists unassisted by computer simulations to effectively predict the consequences of a particular intervention. For this reason, computer simulation has become an important tool for generating hypotheses about the behavior of these systems that can then be tested in the laboratory and clinic. A dynamic data-driven application simulation (DDDAS) was designed by Biospherics to model complex metabolic disease pathways by testing potential binary therapies in simulations at various combinations of two points in the pathways. Since DDDAS chooses the most effective pair-wise combinations, this data-driven system allows for the implementation of real-time data to model or predict a measurement or event. By incorporating data dynamically rather than statically, the predictions and measurements become more reliable. Dyslipidemia, a common precursor to atherosclerosis, can be manifested by high triglycerides, increased apolipoprotein (Apo) B, high levels of LDL, and low levels of HDL. SPX106 and D-tagatose is a combination drug therapy composed of a carbohydrate (D-tagatose) and SPX106. D-tagatose has been studied for the treatment of diabetes for several years, and has the ability to lower blood insulin levels and to decrease glycogen formation. SPX106 is a natural substance that accelerates lipid catabolism and inhibits dyslipidemia. In apolipoprotein E knockout mice (ApoE^-/-), this drug combination has been shown to significantly lower both the amount of atherosclerosis and blood cholesterol levels. This study used 26 male ApoE^-/- mice (n=13 in each group, control and treated). The control group received the normal "Western" diet (Harlan TD88137) and the treatment group received a modified version in which the sucrose was replaced with D-tagatose and 1g of SPX106 was added for every kilogram of chow. Mice were fed the diet for 8 weeks and then sacrificed via cardiac puncture. Blood serum was analyzed for cholesterol concentration. A significant difference was observed between the control and treated groups for total cholesterol levels. FPLC separations were done on fractions from both control and treated groups. A significant difference between VLDL and HDL levels was found between the treated and control mice (p<0.05 for both). Aortas were also taken and preserved in formalin to be quantified for atherosclerosis. Aortic sinuses were frozen in OCT and sectioned using a cryostat and then quantified for atherosclerosis. Treated mice showed statistically significant reduction in atherosclerosis in the aortic arch (p<0.01), the thoracic aorta (p<0.05), and the aortic sinus (p<0.05) as well as a reduction of cholesterol (p<0.05).

Curative effects of oleanolic Acid on formed hypertrophic scars in the rabbit ear model

Hypertrophic scarring is a common proliferative disorder of dermal fibroblasts characterized by collagen overproduction and excessive deposition of extracellular matrix (ECM). There is no consensus about the best therapeutics to produce complete and permanent improvement of scars with few side effects. To investigate the therapeutic effects of oleanolic acid (OA) on hypertrophic scars and explore the possible mechanism of action involved, a rabbit ear model with hypertrophic scars was established. OA (2.5%, 5%, and 10%) was given once daily to the scars for 28 consecutive days. As a result, OA significantly alleviated formed hypertrophic scars on rabbit ears. The levels of TGF-β₁, MMP-1, TIMP-1, and collagens I and III were notably decreased, and the number of apoptosis cells and mRNA expression of MMP-2, caspase-3, and caspase-9 were markedly increased in the scar tissue. The scar elevation index (SEI) was also evidently reduced. Histological findings exhibited significant amelioration of the collagen tissue. These results suggest that OA has the favorable curative effects on formed hypertrophic scars in the rabbit ear model, and the possible mechanism of action is that OA decreases HSFs proliferation and increases HSFs apoptosis by reduction of P311 gene expression and TGF-β₁ production, inhibition of TIMP-1 secretion, enhancement of MMP-2 activity, and subsequently facilitation of degradation of collagen types I and III.

Polydatin ameliorates renal injury by attenuating oxidative stress-related inflammatory responses in fructose-induced urate nephropathic mice

A series of studies have recently demonstrated that the oxidative stress, nuclear factor-kappa B (NF-κB) activation and the subsequent coordinated inflammatory responses played an important role in the pathogenesis of urate nephropathy (UN). Polydatin has been suggested to have the properties of anti-oxidative, anti-inflammatory and nephroprotective effects. However, the possible protective and beneficial effects of polydatin on UN are not fully elucidated. Therefore, we investigated the potential beneficial effects and possible mechanisms of polydatin on UN. In this study, polydatin showed inhibitory activities on xanthine oxidase to repress the level of serum uric acid in vivo and in vitro. Further investigations revealed that polydatin displayed little toxic effects and significantly ameliorated the renal function in fructose-induced UN mice. The nephroprotective activities of polydatin was not only due to the effects on remarkably attenuating the oxidative stress induced by uric acid, but also on markedly suppressing the oxidative stress-related inflammatory cascade, including decreasing the expressions of NF-κB p65, COX-2 and iNOS proteins and inhibiting the productions of TNF-α, PGE(2) and IL-1β. These findings elucidated that polydatin exhibited prominent nephroprotective activities and low toxic effects.

Protective effects of polydatin from Polygonum cuspidatum against carbon tetrachloride-induced liver injury in mice

Polydatin is one of main compounds in Polygonum cuspidatum, a plant with both medicinal and nutritional value. The possible hepatoprotective effects of polydatin on acute liver injury mice induced by carbon tetrachloride (CCl₄) and the mechanisms involved were investigated. Intraperitoneal injection of CCl₄ (50 µl/kg) resulted in a significant increase in the levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and hepatic malondialdehyde (MDA), also a marked enhancement in the expression of hepatic tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and nuclearfactor-kappa B (NF-κB). On the other hand, decreased glutathione (GSH) content and activities of glutathione transferase (GST), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were observed following CCl₄ exposure. Nevertheless, all of these phenotypes were evidently reversed by preadministration of polydatin for 5 continuous days. The mRNA and protein expression levels of hepatic growth factor-beta1 (TGF-β₁) were enhanced further by polydatin. These results suggest that polydatin protects mice against CCl₄-induced liver injury through antioxidant stress and antiinflammatory effects. Polydatin may be an effective hepatoprotective agent and a promising candidate for the treatment of oxidative stress- and inflammation-related diseases.

Anti-inflammatory effect of resveratrol and polydatin by in vitro IL-17 modulation

Interleukin-17 (IL-17) is a proinflammatory cytokine produced, although not exclusively, by T helper 17 recently identified as a distinct T helper lineage mediating tissue inflammation. IL-17 is known to be involved in a number of chronic disorders although the mechanisms regulating its production in inflammatory disease are still unclear. The beneficial properties of the polyphenolic compound resveratrol including its anti-inflammatory, antioxidant, and antitumor effects, its role in the aging process and in the prevention of heart and neurodegenerative diseases are well-known. In addition, derivatives of resveratrol, including glucosylated molecules as polydatin have been linked to similar beneficial effects. We have investigated the effects of resveratrol and polydatin on the in vitro production of IL-17 in a model of inflammation in vitro. The results obtained by activated human peripheral blood mononuclear cells, stimulated with anti-CD3/anti-CD28 monoclonal antibodies and treated with these polyphenolic compounds at different concentrations show that both decrease IL-17 production in a concentration-dependent manner. This study confirms the anti-inflammatory activity of resveratrol and its derivatives and suggests a potential clinical relevance in the therapy of inflammatory diseases.

Polydatin attenuates hypoxic pulmonary hypertension and reverses remodeling through protein kinase C mechanisms

Hypoxic pulmonary hypertension is a life-threatening emergency if untreated. Consistent pulmonary hypertension also leads to arteries and ventricular remodeling. The clinical therapeutic strategy for pulmonary hypertension and the corresponding remodeling mainly interacts with NO, angiotensin II (Ang II) and elevated endothelin (ET) targets. In the present study, we evaluated the effects of polydatin on hypoxia-induced pulmonary hypertension. It was observed that polydatin attenuated hypoxic pulmonary hypertension, reversed remodeling, and regulated NO, Ang II, ET contents in the serum and lung samples. However, forced activation of PKC signaling by its selective activator thymeleatoxin (THX) could abate the effects of polydatain. These results suggest that polydatin might be a promising candidate for hypoxic pulmonary treatment through interaction with PKC mechanisms.

Therapeutic effects of liposome-enveloped Ligusticum chuanxiong essential oil on hypertrophic scars in the rabbit ear model

Hypertrophic scarring, a common proliferative disorder of dermal fibroblasts, results from an overproduction of fibroblasts and excessive deposition of collagen. Although treatment with surgical excision or steroid hormones can modify the symptoms, numerous treatment-related complications have been described. In view of this, we investigated the therapeutic effects of essential oil (EO) from rhizomes of Ligusticum chuanxiong Hort. (Umbelliferae) on formed hypertrophic scars in a rabbit ear model. EO was prepared as a liposomal formulation (liposome-enveloped essential oil, LEO) and a rabbit ear model with hypertrophic scars was established. LEO (2.5, 5, and 10%) was applied once daily to the scars for 28 days. On postoperative day 56, the scar tissue was excised for masson's trichrome staining, detection of fibroblast apoptosis, assays of the levels of collagens I and III, and analysis of the mRNA expression of matrix metalloproteinase-1 (MMP-1), caspase-3 and -9, and transforming growth factor beta 1 (TGF-β₁). In addition, the scar elevation index (SEI) was also determined. As a result, LEO treatment significantly alleviated formed hypertrophic scars on rabbit ears. The levels of TGF-β₁, MMP-1, collagen I, and collagen III were evidently decreased, and caspase -3 and -9 levels and apoptosis cells were markedly increased in the scar tissue. SEI was also significantly reduced. Histological findings exhibited significant amelioration of the collagen tissue. These results suggest that LEO possesses the favorable therapeutic effects on formed hypertrophic scars in the rabbit ear model and may be an effective cure for human hypertrophic scars.

Cardioprotective effect of polydatin against ischemia/reperfusion injury: roles of protein kinase C and mito K(ATP) activation

Polydatin preconditioning (PPC) has been reported to be protective against brain and intestine ischemia/reperfusion injury (I/R injury), but whether polydatin exerts cardioprotective effect against myocardial ischemia/reperfusion and the underlying mechanisms remain unclear. Previous studies have demonstrated that oxidative stress plays an important role in the process of I/R. Elevation of oxidative agents and decline in anti-oxidant substance would promote I/R. Meanwhile, the activation of PKC signaling seems to mediate the cardioprotective effects of many drugs by alleviating Ca(2+) influx. In the present study, we reported for the first time that intravenous administration of polydatin before I/R significantly limited the infarct size, creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) leakage from the damaged myocardium after I/R. The activity of SOD and the content of MDA remarkably changed in the presence of polydatin as well. However, the cardiac function-preserving and myocardial enzymes leakage-limiting effects of polydatin vanished in the presence of PKC inhibitors and mito K(ATP) channel blockers. But there was not a significant change in the activity of SOD and MDA content. We therefore conclude that PPC exerts cardioprotective effect by the activation of PKC-K(ATP)-dependent signaling and the direct anti-oxidative stress mechanisms.

Study on the structural changes of bovine serum albumin with effects on polydatin binding by a multitechnique approach

Polydatin is a traditional Chinese medicine which shows effective biological activity as antimicrobial and antiviral agent. The secondary structure changes of bovine serum albumin (BSA) were investigated by the methods of Fourier transform infrared spectroscopy (FT-IR), circular dichroism (CD) and Raman spectroscopy. The experimental results indicated that polydatin changed the secondary structure of BSA. The presence of polydatin decreased α-helix content of BSA. The conformations of disulfide bridges and the microenvironment of Tyr, Trp residues were also changed.

Polydatin up-regulates Clara cell secretory protein to suppress phospholipase A2 of lung induced by LPS in vivo and in vitro

Background

Lung injury induced by lipopolysaccharide (LPS) remains one of the leading causes of morbidity and mortality in children. The damage to membrane phospholipids leads to the collapse of the bronchial alveolar epithelial barrier during acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Phospholipase A₂ (PLA₂), a key enzyme in the hydrolysis of membrane phospholipids, plays an important traumatic role in pulmonary inflammation, and Clara cell secretory protein (CCSP) is an endogenous inhibitor of PLA₂. Our previous study showed that polydatin (PD), a monocrystalline extracted from a traditional Chinese medicinal herb (Polygonum cuspidatum Sieb, et Zucc), reduced PLA₂ activity and sPLA₂-IIA mRNA expression and mitigated LPS-induced lung injury. However, the potential mechanism for these effects has not been well defined. We have continued to investigate the effect of PD on LPS-induced expression of CCSP mRNA and protein in vivo and in vitro.

Results

Our results suggested that the CCSP mRNA level was consistent with its protein expression. CCSP expression was decreased in lung after LPS challenge. In contrast, PD markedly increased CCSP expression in a concentration-dependent manner. In particular, CCSP expression in PD-pretreated rat lung was higher than in rats receiving only PD treatment.

Conclusion

These results indicated that up-regulation of CCSP expression causing inhibition of PLA₂ activation may be one of the crucial protective mechanisms of PD in LPS-induced lung injury.

Inhibitory effects of essential oil from rhizomes of Ligusticum chuanxiong on hypertrophic scarring in the rabbit ear model

CONTEXT

Hypertrophic scarring, a common proliferative disorder of dermal fibroblasts, results from an overproduction of collagen and excessive deposition of extracellular matrix. Although the treatment with surgical excisions or steroid hormones can modify the symptoms, numerous treatment-related complications have also been established.

OBJECTIVE

To investigate the effects of essential oil (EO) from rhizomes of Ligusticum chuanxiong Hort. (Umbelliferae) on hypertrophic scarring in a rabbit ear model.

MATERIALS AND METHODS

A rabbit ear model of hypertrophic scarring was established. EO (5, 10, and 20%) was applied once daily to the scars for 22 days. After 28 days of post-wounding, excision of scars was respectively performed for both histological examination and assays of the levels of collagen I, collagen III, matrix metalloproteinase-1 (MMP-1), and transforming growth factor beta 1 (TGF-β₁). The scar elevation index (SEI) was also determined.

RESULTS

After 22 days of treatment with indicated concentrations of EO, hypertrophic scarring was significantly inhibited in the rabbit ears. The levels of TGF-β₁, collagen I, and collagen III evidently decreased and MMP-1 level markedly increased in the scar tissue. SEI was also significantly reduced. Immunohistochemical findings exhibited significant amelioration of the scar tissue.

DISCUSSION AND CONCLUSION

EO suppresses hypertrophic scarring in the rabbit ear model and is a probably effective cure for human hypertrophic scarring.

Essential oil from rhizomes of Ligusticum chuanxiong induces apoptosis in hypertrophic scar fibroblasts

CONTEXT

Hypertrophic scarring following surgical procedures, trauma and especially burns can lead to severe functional and cosmetic impairment, causing a decrease in the quality of life. Although a wide choice of treatments is offered, few therapeutic methods are universally accepted because of their side effects.

OBJECTIVE

The effects of the essential oil (EO) extracted from rhizomes of Ligusticum chuanxiong Hort. (Umbelliferae) in human hypertrophic scar fibroblasts (HSFs) are investigated for the first time.

MATERIALS AND METHODS

Chemical composition of hydrodistilled EO obtained from rhizomes of Ligusticum chuanxiong was analyzed by gas chromatography-mass spectrometry (GC-MS). The effects of EO on cell viability, apoptosis rate, mitochondrial membrane potential (MMP), lactate dehydrogenase (LDH), reactive oxygen species (ROS) and caspase-3 in HSFs were investigated.

RESULTS

The experimental results showed that EO significantly inhibited cell viability, elicited morphological changes and induced apoptosis in HSFs. EO also evidently increased the loss of MMP, the levels of LDH release and cellular ROS production, and the activity of caspase-3.

DISCUSSION AND CONCLUSION

EO-induced apoptosis was at least partially carried out via destruction of the intracellular antioxidant system and elicitation of excessive ROS accumulation in HSFs, which impaired mitochondrial membranes and elicited caspase-3 activation. EO could be an effective cure for human hypertrophic scar.

Screening for anti-lipase properties of 37 traditional Chinese medicinal herbs

BACKGROUND

To find new, crude anti-obesity drugs from natural sources through the inhibition of adsorption of dietary lipids, in vitro porcine pancreatic lipase (PPL; triacylglycerol lipase, EC 3.1.1.3) inhibitory tests were carried out on selected plants with weight-reducing or related potential, used in Chinese traditional medicine.

METHODS

The methanolic extracts of 37 traditional Chinese herbal medicines of different families were assayed for their in vitro activity against PPL by using spectrophotometry with 2,4-dinitrophenyl butyrate as a synthetic substrate. Coexistent phytochemicals, or those present in high levels, in the 3 most promising Chinese herbs were tested for their anti-lipase activity.

RESULTS

Extracts from 2 herbs, Prunella vulgaris L. (Labiatae) and Rheum palmatum L. (Polygonaceae), at a concentration of 200 mg/mL, significantly inhibited PPL-by 74.7% and 53.8%, respectively. Quercetin exhibited better activity (27.4%) than all the other phytochemicals at a final concentration of 25 mg/mL in the assay system, followed by luteolin, with an activity of 17.3%.

CONCLUSION

The results support the view that herbs represent a rich source of anti-lipase compounds. The screening of the methanolic extracts of 37 Chinese medicinal plants in vitro led to the identification of several extracts with potential activity against PPL, in particular, P. vulgaris and R. palmatum. We also found that several monomeric chemicals in these herbs exhibited good or moderate activity against PPL. To the best of our knowledge, these traditional Chinese herbal medicines or phytochemicals have not been previously screened for their lipase inhibitory activity.