Ellagic acid inhibits PDGF-BB-induced vascular smooth muscle cell proliferation and prevents atheroma formation in streptozotocin-induced diabetic rats

Ellagic acid as potential therapeutic compound for diabetes and its complications: a systematic review from bench to bed

Diabetes mellitus (DM) is a worldwide-concerning disease with a rising prevalence. There are many ongoing studies aimed at finding new and effective treatments. Ellagic acid (EA) is a natural polyphenolic compound abundant in certain fruits and vegetables. It is the objective of this investigation to assess the effectiveness and preventive mechanisms of EA on DM and associated complications. This systematic review used PubMed, Scopus, and Google Scholar as search databases using a predetermined protocol from inception to June 2024. We assessed all related English studies, including in vitro, in vivo, and clinical trials. EA counteracted DM and its complications by diminishing inflammation, oxidative stress, hyperglycemia, apoptosis, insulin resistance, obesity, lipid profile, and histopathological alterations. Several mechanisms contributed to the anti-diabetic effect of EA, the most significant being the upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), peroxisome proliferator-activated receptor gamma (PPAR-γ), protein kinase B, and downregulation of nuclear factor-kappa-B (NF-κB) gene expression. EA also revealed protective effects against diabetes complications, such as diabetic-induced hepatic damage, testicular damage, endothelial dysfunction, muscle dysfunction, retinopathy, nephropathy, cardiomyopathy, neuropathy, and behavioral deficit. Administration of EA could have various protective effects in preventing, treating, and alleviating DM and its complications. Although it could be considered a cost-effective, safe, and accessible treatment, to fully establish the effectiveness of EA as a medication for DM, it is crucial to conduct further well-designed studies.

Role of polyphenols in the management of diabetic complications

BACKGROUND

Diabetes Mellitus is an endocrine disorder that will affect, about 693 million adults by 2045 worldwide, (>50% increase from 2017). The conventional treatment of the disease, include the oral hypoglycemic drugs which are given in combination with other drugs and are known to possess various adverse effects like gastrointestinal disturbance, nausea, water retention etc. PURPOSE: Due to the urgent need of combating this disorder without side effects, the alternative and complementary therapies should be explored due to their natural origins and comparable safety. Herbal sources serve as new leads, due to the presence of phytoconstituents with potential therapeutic properties, efficacy and safety. In this review, we tried to summarise the polyphenolic phytoconstituents effective in the treatment of diabetic complications.

METHODS

A systematic literature search was conducted using 4 databases (Google scholar, Pubmed, Scopus, Embase) for the identification of relevant data. Search was performed using various key words such as "diabetes", "polyphenols", "marine sources","anti-diabetic polyphenols". The in vitro studies involving the cell lines used in diabetes and animal models were also considered for inclusion. Additional research papers were identified by reviewing abstracts, scrutinizing reference lists, and reviewing previously published review articles.

RESULTS

Polyphenols, a group of phytoconstituents are known worldwide for their tremendous antioxidant potential. So, various research groups have explored their mechanism and therapeutic value in diabetic complications, to improve the insulin sensitivity and glucose metabolism, in controlling the glycemic conditions.

CONCLUSION

Polyphenols exhibit effective therapeutic potential in managing diabetic complications through their multifaceted mechanism of action. They exhibit antioxidative, anti-inflammatory, and anti-glycemic properties, which collectively contribute to their beneficial effects in mitigating diabetic complications. Thus, the inclusion of polyphenols into the diet, may be cosidered as an approach of managing diabetes on long term basis. In this review, we have tried to identify polyphenols effective in diabetes and summarize their mechanism of action along with their potential, for the treatment of diabetic complications.

Research progress on the role of PDGF/PDGFR in type 2 diabetes

Platelet-derived growth factors (PDGFs) are basic proteins stored in the α granules of platelets. PDGFs and their receptors (PDGFRs) are widely expressed in platelets, fibroblasts, vascular endothelial cells, platelets, pericytes, smooth muscle cells and tumor cells. The activation of PDGFR plays a number of critical roles in physiological functions and diseases, including normal embryonic development, cellular differentiation, and responses to tissue damage. In recent years, emerging experimental evidence has shown that activation of the PDGF/PDGFR pathway is involved in the development of diabetes and its complications, such as atherosclerosis, diabetic foot ulcers, diabetic nephropathy, and retinopathy. Research on targeting PDGF/PDGFR as a treatment has also made great progress. In this mini-review, we summarized the role of PDGF in diabetes, as well as the research progress on targeted diabetes therapy, which provides a new strategy for the treatment of type 2 diabetes.

Promising remedies for cardiovascular disease: Natural polyphenol ellagic acid and its metabolite urolithins

BACKGROUND

Cardiovascular disease (CVD) is a significant worldwide factor contributing to human fatality and morbidity. With the increase of incidence rates, it is of concern that there is a lack of current therapeutic alternatives because of multiple side effects. Ellagic acid (EA), the natural polyphenol (C₁₄H₆O₈), is abundant in pomegranates, berries, and nuts. EA and its intestinal microflora metabolite, urolithins, have recently attracted much attention as a potential novel "medicine" because of their wide pharmacological properties.

PURPOSE

This study aimed to critically analyze available literature to summarize the beneficial effects of EA and urolithins, and highlights their druggability and therapeutic potential in various CVDs.

METHODS

We systematically studied research and review articles between 1984 and 2022 available on various databases to obtain the data on EA and urolithins with no language restriction. Their cardiovascular protective activities, underlying mechanism, and druggability were highlighted and discussed comprehensively.

RESULTS

We found that EA and urolithins may exert preventive and curative effects on CVD with negligible side effects and possibly regulate lipid metabolism imbalance, pro-inflammatory factor production, vascular smooth muscle cell proliferation, cardiomyocyte apoptosis, endothelial cell dysfunction, and Ca²⁺ intake and release. Potentially, this may lead to the prevention and amelioration of atherosclerosis, hypertension, myocardial infarction, cardiac fibrosis, cardiomyopathy, cardiac arrhythmias, and cardiotoxicities in vivo. Several molecules and signaling pathways are associated with their therapeutic actions, including phosphatidylinositol 3-kinase/protein kinase B, mitogen-activated protein kinase, NF-κB, nuclear factor erythroid-2 related factor 2, sirtuin1, miRNA, and extracellular signal-regulated kinase 1/2.

CONCLUSION

In vitro and in vivo studies shows that EA and urolithins could be used as valid candidates for early prevention and effective therapeutic strategies for various CVDs.

Ellagic acid increases implantation rates with its antifibrotic effect in the rat model of intrauterine adhesion

Intrauterine adhesions (IUA) are defined as the adhesion of opposing endometrial tissue with dense fibrous adhesive bands within the uterine cavity. With the increase in cesarean sections and endometrial surgical procedures, intrauterine adhesions have become a problem with increasing incidence and decreasing implantation. The purpose of the study was to investigate the effect of ellagic acid (EA), a phenolic compound, on fibrosis in IUA model rats. Another goal of the study was to increase endometrial receptivity with EA. The groups in the study were planned as control, DMSO, EA, IUA, IUA+DMSO, and IUA+EA, with 8 Sprague Dawley rats in each group. EA was administered at a dose of 100 mg/kg/day for 35 days. At the end of the experiment, the uterine tissues of the rats were removed. Histochemical staining was used to validate the IUA model and determine the degree of fibrosis. The levels of some fibrosis-related genes and proteins in the obtained uterine tissues were evaluated. In addition, implantation rates were determined. In our findings, it was observed that the fibrotic structure was decreased in the treated IUA+EA group compared to the IUA group, while fibrotic improvement was supported by down-regulation of TGFβ1 activity and up-regulation of BMP7 activity. The increase in the expression of the endometrial marker LIF with EA treatment was consistent with the increase in implantation rates with treatment. As a result of the study, it can be said that EA applied as a treatment against IUA causes healing in uterine tissue by reducing fibrosis and increases implantation rates by increasing endometrial receptivity.

Potential roles of ellagic acid on metabolic variables in diabetes mellitus: A systematic review

Diabetes mellitus is a widespread endocrine disorder globally. Due to its antioxidant and anti-inflammatory properties, ellagic acid has the potential to improve the metabolic effects of chronic non-communicable diseases. This systematic review summarizes current evidence about the potential effects of ellagic acid on metabolic variables in diabetes mellitus. A comprehensive systematic literature search was conducted in databases such as PubMed, Scopus, EMBASE, ProQuest and Google Scholar from inception until March 2022. All animal studies and clinical trials were eligible for inclusion. Studies using in vitro models or published in a non-English language were excluded. Of 1320 articles, 23 were selected for assessment, including 21 animal studies and two randomized controlled trial studies. Following ellagic acid administration, findings reported improvement in FBS, HbA1c, insulin (20, 8 and 12 studies, respectively), TG, TC, HDL-C (13, 10 and 5 studies, respectively), MDA, GSH, CAT, SOD (11, 6, 3 and 4 studies, respectively), and TNF-α and IL-6 (6 and 3 studies, respectively). In conclusion, ellagic acid may improve glycaemic indicators, dyslipidaemia, oxidative stress and inflammation in diabetes mellitus. However, further clinical trials are needed to explore the mechanisms more precisely and to observe the applied consequences.

Deciphering the Mechanism of Wogonin, a Natural Flavonoid, on the Proliferation of Pulmonary Arterial Smooth Muscle Cells by Integrating Network Pharmacology and In Vitro Validation

Wogonin is one of the main active components of Scutellaria baicalensis, which has anti-inflammatory, anti-angiogenesis, and anti-fibrosis effects. Nevertheless, the effect of wogonin on pulmonary hypertension (PH) still lacks systematic research. This study aims to elucidate the potential mechanism of wogonin against PH through network pharmacology and further verify it through biological experiments in pulmonary arterial smooth muscle cells (PASMCs). The potential targets and pathways of wogonin against PH were predicted and analyzed by network pharmacology methods and molecular docking technology. Subsequently, the proliferation of PASMCs was induced by platelet-derived growth factor-BB (PDGF-BB). Cell viability and migration ability were examined. The method of Western blot was adopted to analyze the changes in related signaling pathways. Forty potential targets related to the effect of wogonin against PH were obtained. Based on the protein-protein interaction (PPI) network, gene-ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment, and molecular docking, it was shown that the effect of wogonin against PH is closely related to the proliferation of PASMCs and the hypoxia-inducible factor-1α (HIF-1α) pathway. A variety of results from biological experiments verified that wogonin can effectively inhibit the proliferation, migration, and phenotypic transformation of PDGF-BB-mediated PASMCs. In addition, the anti-proliferation effect of wogonin may be achieved by regulating HIF-1/ NADPH oxidase 4 (NOX4) pathway.

Putative role of natural products as Protein Kinase C modulator in different disease conditions

INTRODUCTION

Protein kinase C (PKC) is a promising drug target for various therapeutic areas. Natural products derived from plants, animals, microorganisms, and marine organisms have been used by humans as medicine from prehistoric times. Recently, several compounds derived from plants have been found to modulate PKC activities through competitive binding with ATP binding site, and other allosteric regions of PKC. As a result fresh race has been started in academia and pharmaceutical companies to develop an effective naturally derived small-molecule inhibitor to target PKC activities. Herein, in this review, we have discussed several natural products and their derivatives, which are reported to have an impact on PKC signaling cascade.

METHODS

All information presented in this review article regarding the regulation of PKC by natural products has been acquired by a systematic search of various electronic databases, including ScienceDirect, Scopus, Google Scholar, Web of science, ResearchGate, and PubMed. The keywords PKC, natural products, curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, protocatechuic acid, tannic acid, PKC modulators from marine organism, bryostatin, staurosporine, midostaurin, sangivamycin, and other relevant key words were explored.

RESULTS

The natural products and their derivatives including curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, bryostatin, staurosporine, and midostaurin play a major role in the management of PKC activity during various disease progression.

CONCLUSION

Based on the comprehensive literature survey, it could be concluded that various natural products can regulate PKC activity during disease progression. However, extensive research is needed to circumvent the challenge of isoform specific regulation of PKC by natural products.

MiR-340 Promotes the Proliferation of Vascular Smooth Muscle Cells by Targeting von Hippel-Lindau Tumor Suppressor Gene

ABSTRACT

MiRNAs play key roles in the proliferation of vascular smooth muscle cells (VSMCs). However, the roles and underlying mechanism of miRNAs in VSMCs are not fully understood. The aim of this study was to evaluate the role of miR-340 in the proliferation of VSMCs. The expression levels of miR-340 and von Hippel-Lindau tumor suppressor (VHL) in VSMCs induced by platelet-derived growth factor-BB or fetal bovine serum were measured by q-polymerase chain reaction. The effects of miR-340 and VHL on cell proliferation and invasion were evaluated by CCK-8 assay. Target gene prediction and screening as well as luciferase reporter assay were performed to verify the downstream target genes of miR-340. Western blotting was used to detect the protein expression levels of vascular endothelial growth factor and VHL. Our results showed that the miR-340 was upregulated in platelet-derived growth factor-BBor fetal bovine serum-induced VSMCs. In addition, overexpression of miR-340 promoted VSMCs proliferation and invasion. Moreover, VHL was found to be a potential target for miR-340 and upregulation of VHL-inhibited VSMCs proliferation. MiR-340 plays a critical role in VSMC proliferation and neointimal hyperplasia in rats' carotid balloon injury model. Reduced expression levels of miR-340 promoted VHL-inhibited VSMCs proliferation. In conclusion, miR-340 may play a role in the regulation of proliferation of VSMCs by inhibition of VHL.

Ellagic Acid as a Tool to Limit the Diabetes Burden: Updated Evidence

Oxidative stress contributes not only to the pathogenesis of type 2 diabetes (T2D) but also to diabetic vascular complications. It follows that antioxidants might contribute to limiting the diabetes burden. In this review we focus on ellagic acid (EA), a compound that can be obtained upon intestinal hydrolysis of dietary ellagitannins, a family of polyphenols naturally found in several fruits and seeds. There is increasing research on cardiometabolic effects of ellagitannins, EA, and urolithins (EA metabolites). We updated research conducted on these compounds and (I) glucose metabolism; (II) inflammation, oxidation, and glycation; and (III) diabetic complications. We included studies testing EA in isolation, extracts or preparations enriched in EA, or EA-rich foods (mostly pomegranate juice). Animal research on the topic, entirely conducted in murine models, mostly reported glucose-lowering, antioxidant, anti-inflammatory, and anti-glycation effects, along with prevention of micro- and macrovascular diabetic complications. Clinical research is incipient and mostly involved non-randomized and low-powered studies, which confirmed the antioxidant and anti-inflammatory properties of EA-rich foods, but without conclusive results on glucose control. Overall, EA-related compounds might be potential agents to limit the diabetes burden, but well-designed human randomized controlled trials are needed to fill the existing gap between experimental and clinical research.

Insight into Polyphenol and Gut Microbiota Crosstalk: Are Their Metabolites the Key to Understand Protective Effects against Metabolic Disorders?

Lifestyle factors, especially diet and nutrition, are currently regarded as essential avenues to decrease modern-day cardiometabolic disorders (CMD), including obesity, metabolic syndrome, type 2 diabetes, and atherosclerosis. Many groups around the world attribute these trends, at least partially, to bioactive plant polyphenols given their anti-oxidant and anti-inflammatory actions. In fact, polyphenols can prevent or reverse the progression of disease processes through many distinct mechanisms. In particular, the crosstalk between polyphenols and gut microbiota, recently unveiled thanks to DNA-based tools and next generation sequencing, unravelled the central regulatory role of dietary polyphenols and their intestinal micro-ecology metabolites on the host energy metabolism and related illnesses. The objectives of this review are to: (1) provide an understanding of classification, structure, and bioavailability of dietary polyphenols; (2) underline their metabolism by gut microbiota; (3) highlight their prebiotic effects on microflora; (4) discuss the multifaceted roles of their metabolites in CMD while shedding light on the mechanisms of action; and (5) underscore their ability to initiate host epigenetic regulation. In sum, the review clearly documents whether dietary polyphenols and micro-ecology favorably interact to promote multiple physiological functions on human organism.

Butanolic Extract of Noni Inhibits Proliferation, Inflammation, and Proprotein Convertase Subtilisin Kexin Type 9 (PCSK9) Expression in Cultured Smooth Muscle Cells

Platelet-derived growth factor-BB (PDGF-BB) plays a central role in smooth muscle cell (SMC) proliferation and inflammation, being involved in atherosclerotic cardiovascular disease. We have previously found that butanolic extract of noni, a tropical plant belonging to the family Rubiaceae, exerts anti-inflammatory effects on endothelial cells exposed to advanced glycation end products (AGEs). Here, we examined the effects of noni extract on oxidative stress production, growth, and inflammatory reactions in PDGF-BB or AGE-exposed SMCs. Reactive oxygen species (ROS) generation, cell proliferation, and adhesion were measured by a fluorescent dye, a colorimetric agent, and labeled THP-1 cells, respectively. Gene and protein expression was evaluated by real-time reverse transcription-polymerase chain reaction and Western blot analysis. Butanolic extract of noni reduced ROS production, monocyte chemoattractant protein-1, intercellular adhesion molecule-1, and proprotein convertase subtilisin kexin type 9 (PCSK9) expression, and proliferation in, and THP-1 cell adhesion to, PDGF-BB-exposed SMCs. Gene expression and protein level of receptor for AGEs (RAGE) were significantly decreased by noni extract in SMCs. Furthermore, AGEs significantly increased PCSK9 mRNA and protein levels in SMCs, which were inhibited by noni extract or an antioxidant N-acetylcysteine. Our present study suggests that butanolic extract of noni not only inhibits the PDGF-BB-induced proliferation and inflammatory reactions in SMCs through its antioxidative properties but also reduces PCSK9 levels in AGE-exposed SMCs via suppression of RAGE expression. Butanolic extract of noni may play a protective role against atherosclerosis.

Synergistic mechanisms of Sanghuang-Danshen phytochemicals on postprandial vascular dysfunction in healthy subjects: A network biology approach based on a clinical trial

With the increased risk of cardiovascular disease, the use of botanicals for vascular endothelial dysfunction has intensified. Here, we explored the synergistic mechanisms of Sanghuang–Danshen (SD) phytochemicals on the homeostatic protection against high-fat-induced vascular dysfunction in healthy subjects, using a network biology approach, based on a randomised crossover clinical trial. Seventeen differential markers identified in blood samples taken at 0, 3 and 6 h post-treatment, together with 12SD phytochemicals, were mapped onto the network platform, termed the context-oriented directed associations. The resulting vascular sub-networks illustrated associations between 10 phytochemicals with 32 targets implicated in 143 metabolic/signalling pathways. The three key events included adhesion molecule production (ellagic acid, fumaric acid and cryptotanshinone; VCAM-1, ICAM-1 and PLA2G2A; fatty acid metabolism), platelet activation (ellagic acid, protocatechuic acid and tanshinone IIA; VEGFA, APAF1 and ATF3; mTOR, p53, Rap1 and VEGF signalling pathways) and endothelial inflammation (all phytochemicals, except cryptotanshinone; 29 targets, including TP53 and CASP3; MAPK and PI3K-Akt signalling pathways, among others). Our collective findings demonstrate a potential of SD to protect unintended risks of vascular dysfunction in healthy subjects, providing a deeper understanding of the complicated synergistic mechanisms of signature phytochemicals in SD.

Production of bioactive cyclotides in somatic embryos of Viola odorata

Viola odorata L. (Violaceae), an Indian medicinal plant, contains a plethora of cyclotides, which are a class of cyclic peptides derived from plants, possessing several applications. Somatic embryo culture of V. odorata was developed, via indirect somatic embryogenesis, to serve as an alternative to natural plant biomass for sustainable and continuous production of its bioactive ingredients, such as cyclotides. Among the various combinations of phytohormones tested, Murashige and Skoog medium supplemented with 1 mg/l thidiazuron gave rise to the maximum frequency of induction (86.7%) and a high number of somatic embryos (3) from an embryogenic callus. Identification and characterization of cyclotides in the somatic embryos were carried out using a Fourier transform mass spectrometer coupled with liquid chromatography (LC-FTMS). Among the cyclotides identified in the study, few were found to be exclusively present in the somatic embryo culture. Furthermore, the relative abundance of the cyclotides was higher in somatic embryo extract than in the natural plant extract. The biological activities (cytotoxic, haemolytic and antimicrobial) of the somatic embryos and the parent plant were compared. Unlike the natural plants, the somatic embryo extracts demonstrated specificity i.e. they were found to be potent against cancerous cells but not against non-cancerous cell line or red blood cells. In contrast to the plant extract, the somatic embryos extracts were found to be potent against Escherichia coli and Staphylococcus aureus. These results suggest that somatic embryos of V. odorata (rich in cyclotides) can be used as an alternative to plant biomass for its therapeutic applications and germplasm conservation.

Attenuation of diabetic retinopathy in rats by ellagic acid through inhibition of AGE formation

Diabetic retinopathy (DR) is a major concern for blindness all over the world. Diabetic retinopathy is associated with thickening of basement membrane, retinal thinning, retinal detachment, and pericyte death. Advanced glycation end products (AGEs) mediate the progression of DR by stimulating the expression of RAGE and VEGF which subsequently damages the blood-retinal barrier. Employing a set of in vitro protein glycation systems, earlier we demonstrated antiglycating potential of ellagic acid (EA). In this study, we evaluated the efficacy of EA to prevent in vivo accumulation of AGE and to ameliorate retinal changes in diabetic rats. Streptozotocin-induced diabetic rats were fed either with 0.2 or 2% EA in the diet for 12 weeks. Effect of EA on retinal function was assessed with electroretinogram (ERG). At the end of the experiment, rats were scarified and retina was collected. Histology was carried out with H&E staining and immunohistochemistry. Formation of AGE product (CML) and activation of RAGE was analyzed by immunoblotting and immunohistochemistry. Expression of GFAP, VEGF, Bax and HIF-1α was assessed by qRT-PCR and immunoblotting. Dietary supplementation of EA to diabetic rats resulted in: (1) inhibition of accumulation of CML and activation of RAGE in retina, (2) attenuation of expression of GFAP, VEGF, and HIF-1α in retina, (3) attenuation of cell death by reducing proapoptic mediator Bax and (4) amelioration of retinal thickness and function. In conclusion, EA attenuated the retinal abnormalities including angiogenesis, hypoxia and cell death by inhibiting AGE-RAGE mediated cellular events.

Improvements in Metabolic Health with Consumption of Ellagic Acid and Subsequent Conversion into Urolithins: Evidence and Mechanisms

Ellagic acid (EA) is a naturally occurring polyphenol found in some fruits and nuts, including berries, pomegranates, grapes, and walnuts. EA has been investigated extensively because of its antiproliferative action in some cancers, along with its anti-inflammatory effects. A growing body of evidence suggests that the intake of EA is effective in attenuating obesity and ameliorating obesity-mediated metabolic complications, such as insulin resistance, type 2 diabetes, nonalcoholic fatty liver disease, and atherosclerosis. In this review, we summarize how intake of EA regulates lipid metabolism in vitro and in vivo, and delineate the potential mechanisms of action of EA on obesity-mediated metabolic complications. We also discuss EA as an epigenetic effector, as well as a modulator of the gut microbiome, suggesting that EA may exert a broader spectrum of health benefits than has been demonstrated to date. Therefore, this review aims to suggest the potential metabolic benefits of consumption of EA-containing fruits and nuts against obesity-associated health conditions.

Reprint of: Effect of fermentation parameters, elicitors and precursors on camptothecin production from the endophyte Fusarium solani

Volumetric productivity of camptothecin from the suspension culture of the endophyte Fusarium solani was enhanced up to ∼152 fold (from 0.19μgl(-1)d(-1) to 28.9μgl(-1)d(-1)) under optimized fermentation conditions including initial pH (6.0), temperature (32°C) and agitation speed (80rpm) with (5% (v/v)) ethanol as medium component. Among various elicitors and precursors studied, tryptamine (0.5mM) as precursor and bovine serum albumin (BSA) (0.075mM) as an elicitor added on day 6 of the cultivation period resulted in maximum enhancement of camptothecin concentration (up to 4.5 and 3.4-fold, respectively). These leads provide immense scope for further enhancement in camptothecin productivity at bioreactor level. The cytotoxicity analysis of the crude camptothecin extract from the fungal biomass revealed its high effectiveness against colon and mammary gland cancer cell lines.

Ellagic acid protects against arsenic toxicity in isolated rat mitochondria possibly through the maintaining of complex II

Chronic arsenic exposure has been linked to many health problems including diabetes and cancer. In the present study, we assessed the protective effect of ellagic acid (EA) against toxicity induced by arsenic in isolated rat liver mitochondria. Reactive oxygen species (ROS) and mitochondrial membrane potential decline were assayed using dichlorofluorescein diacetate and rhodamine 123, respectively, and dehydrogenase activity obtained by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide conversion assay. Arsenic increased ROS levels and mitochondrial dysfunction, which led to a reduction in mitochondrial total dehydrogenase activity. Mitochondria pretreated with EA exposed to arsenic at various concentrations led to a reversal of ROS production and mitochondrial damage. Our results showed that mitochondria were significantly affected when exposed to arsenic, which resulted in excessive ROS production and mitochondrial membrane disruption. Pretreatment with EA, reduced ROS amounts, mitochondrial damage, and restored total dehydrogenase activity specifically associated with mitochondrial complex II. EA protective characteristics may be accomplished particularly throughout the mitochondrial maintenance either directly by its antioxidant property or indirectly through its maintaining of complex II. These findings also suggest a potential role for EA in treating or preventing mitochondria associated disorders.

Polyphenol compounds and PKC signaling

BACKGROUND

Naturally occurring polyphenols found in food sources provide huge health benefits. Several polyphenolic compounds are implicated in the prevention of disease states, such as cancer. One of the mechanisms by which polyphenols exert their biological actions is by interfering in the protein kinase C (PKC) signaling pathways. PKC belongs to a superfamily of serine-threonine kinase and are primarily involved in phosphorylation of target proteins controlling activation and inhibition of many cellular processes directly or indirectly.

SCOPE OF REVIEW

Despite the availability of substantial literature data on polyphenols' regulation of PKC, no comprehensive review article is currently available on this subject. This article reviews PKC-polyphenol interactions and its relevance to various disease states. In particular, salient features of polyphenols, PKC, interactions of naturally occurring polyphenols with PKC, and future perspective of research on this subject are discussed.

MAJOR CONCLUSIONS

Some polyphenols exert their antioxidant properties by regulating the transcription of the antioxidant enzyme genes through PKC signaling. Regulation of PKC by polyphenols is isoform dependent. The activation or inhibition of PKC by polyphenols has been found to be dependent on the presence of membrane, Ca(2+) ion, cofactors, cell and tissue types etc. Two polyphenols, curcumin and resveratrol are in clinical trials for the treatment of colon cancer.

GENERAL SIGNIFICANCE

The fact that 74% of the cancer drugs are derived from natural sources, naturally occurring polyphenols or its simple analogs with improved bioavailability may have the potential to be cancer drugs in the future.

Urolithin A attenuates ox-LDL-induced endothelial dysfunction partly by modulating microRNA-27 and ERK/PPAR-γ pathway

SCOPE

Endothelial dysfunction and inflammation are both common events occurring during the development of atherosclerosis. Previous studies have shown that urolithins, the intestinal microflora metabolites of ellagitannin, exhibit anti-inflammation and antioxidative properties. This study aims to investigate the protective effect of urolithin A (UA) on ox-LDL-induced (where ox-LDL is oxidized low-density lipoprotein) endothelial dysfunction and possible modes of action.

METHODS AND RESULTS

Human artery endothelial cells were incubated with 50 μg/mL ox-LDL and various concentrations of UA for 24 h. UA improved the productions of nitric oxide and endothelial nitric oxide synthase in a dose-dependent manner. UA markedly reduced the expressions of ICAM-1 (intercellular adhesion molecule 1) and MCP-1 (monocyte chemotactic protein 1) and further attenuated THP-1 (human acute monocytic leukemia cell line) cell adhesion. In addition, UA suppressed expressions of tumor necrosis factor α, interleukin 6, and endothelin 1, and increased PPAR-γ (peroxisome proliferators activated receptor gamma) mRNA expression. Moreover, UA decreased miR-27 expression, and overexpression of miR-27 by adding pre-miR-27 abolished the ability of UA to improve ox-LDL-induced PPAR-γ decrease. Furthermore, UA significantly downregulated phosphorylated ERK1/2 (where ERK is extracellular signal-regulated kinase) while decreasing interleukin 6 level and elevating PPAR-γ.

CONCLUSIONS

UA could alleviate endothelial dysfunction induced by ox-LDL partially through modulating miR-27 expression and ERK/PPAR-γ pathway.

Effect of fermentation parameters, elicitors and precursors on camptothecin production from the endophyte Fusarium solani

Volumetric productivity of camptothecin from the suspension culture of the endophyte Fusarium solani was enhanced up to ∼152 fold (from 0.19 μg l(-1) d(-1) to 28.9 μg l(-1) d(-1)) under optimized fermentation conditions including initial pH (6.0), temperature (32 °C) and agitation speed (80 rpm) with (5% (v/v)) ethanol as medium component. Among various elicitors and precursors studied, tryptamine (0.5 mM) as precursor and bovine serum albumin (BSA) (0.075 mM) as an elicitor added on day 6 of the cultivation period resulted in maximum enhancement of camptothecin concentration (up to 4.5 and 3.4-fold, respectively). These leads provide immense scope for further enhancement in camptothecin productivity at bioreactor level. The cytotoxicity analysis of the crude camptothecin extract from the fungal biomass revealed its high effectiveness against colon and mammary gland cancer cell lines.

Gentiana lutea exerts anti-atherosclerotic effects by preventing endothelial inflammation and smooth muscle cell migration

BACKGROUND AND AIMS

Studies suggest that Gentiana lutea (GL), and its component isovitexin, may exhibit anti-atherosclerotic properties. In this study we sought to investigate the protective mechanism of GL aqueous root extract and isovitexin on endothelial inflammation, smooth muscle cell migation, and on the onset and progression of atherosclerosis in streptozotocin (STZ)-induced diabetic rats.

METHODS AND RESULTS

Our results show that both GL extract and isovitexin, block leukocyte adhesion and generation of reactive oxygen species in human umbilical vein endothelial cells (HUVECs) and rat aortic smooth muscle cells (RASMCs), following TNF-alpha and platelet derived growth factor-BB (PDGF-BB) challenges respectively. Both the extract and isovitexin blocked TNF-α induced expression of ICAM-1 and VCAM-1 in HUVECs. PDGF-BB induced migration of RASMCs and phospholipase C-γ activation, were also abrogated by GL extract and isovitexin. Fura-2 based ratiometric measurements demonstrated that, both the extact, and isovitexin, inhibit PDGF-BB mediated intracellular calcium rise in RASMCs. Supplementation of regular diet with 2% GL root powder for STZ rats, reduced total cholesterol in blood. Oil Red O staining demonstrated decreased lipid accumulation in aortic wall of diabetic animals upon treatment with GL. Medial thickness and deposition of collagen in the aortic segment of diabetic rats were also reduced upon supplementation. Immunohistochemistry demonstrated reduced expression of vascular cell adhesion molecule-1 (VCAM-1), inducible nitric oxide synthase (iNOS), and vascular endothelial cadherin (VE-cadherin) in aortic segments of diabetic rats following GL treatment.

CONCLUSIONS

Thus, our results support that GL root extract/powder and isovitexin exhibit anti-atherosclerotic activities.

Red Raspberries and Their Bioactive Polyphenols: Cardiometabolic and Neuronal Health Links

Diet is an essential factor that affects the risk of modern-day metabolic diseases, including cardiovascular disease, diabetes mellitus, obesity, and Alzheimer disease. The potential ability of certain foods and their bioactive compounds to reverse or prevent the progression of the pathogenic processes that underlie these diseases has attracted research attention. Red raspberries (Rubus idaeus L.) are unique berries with a rich history and nutrient and bioactive composition. They possess several essential micronutrients, dietary fibers, and polyphenolic components, especially ellagitannins and anthocyanins, the latter of which give them their distinctive red coloring. In vitro and in vivo studies have revealed various mechanisms through which anthocyanins and ellagitannins (via ellagic acid or their urolithin metabolites) and red raspberry extracts (or the entire fruit) could reduce the risk of or reverse metabolically associated pathophysiologies. To our knowledge, few studies in humans are available for evaluation. We review and summarize the available literature that assesses the health-promoting potential of red raspberries and select components in modulating metabolic disease risk, especially cardiovascular disease, diabetes mellitus, obesity, and Alzheimer disease-all of which share critical metabolic, oxidative, and inflammatory links. The body of research is growing and supports a potential role for red raspberries in reducing the risk of metabolically based chronic diseases.

Antidiabetic Effects of Simple Phenolic Acids: A Comprehensive Review

Diabetes mellitus (DM) has become a major public health threat across the globe. Current antidiabetic therapies are based on synthetic drugs that very often have side effects. It has been widely acknowledged that diet plays an important role in the management of diabetes. Phenolic acids are widely found in daily foods such as fruits, vegetables, cereals, legumes, and wine and they provide biological, medicinal, and health properties. Simple phenolic acids have been shown to increase glucose uptake and glycogen synthesis, improve glucose and lipid profiles of certain diseases (obesity, cardiovascular diseases, DM, and its complication). The current review is an attempt to list out the antidiabetic effects of simple phenolic acids from medicinal plants and botanical foods.

Role of Polyphenols and Other Phytochemicals on Molecular Signaling

Optimized nutrition through supplementation of diet with plant derived phytochemicals has attracted significant attention to prevent the onset of many chronic diseases including cardiovascular impairments, cancer, and metabolic disorder. These phytonutrients alone or in combination with others are believed to impart beneficial effects and play pivotal role in metabolic abnormalities such as dyslipidemia, insulin resistance, hypertension, glucose intolerance, systemic inflammation, and oxidative stress. Epidemiological and preclinical studies demonstrated that fruits, vegetables, and beverages rich in carotenoids, isoflavones, phytoestrogens, and phytosterols delay the onset of atherosclerosis or act as a chemoprotective agent by interacting with the underlying pathomechanisms. Phytochemicals exert their beneficial effects either by reducing the circulating levels of cholesterol or by inhibiting lipid oxidation, while others exhibit anti-inflammatory and antiplatelet activities. Additionally, they reduce neointimal thickening by inhibiting proliferation of smooth muscle cells and also improve endothelium dependent vasorelaxation by modulating bioavailability of nitric-oxide and voltage-gated ion channels. However, detailed and profound knowledge on specific molecular targets of each phytochemical is very important to ensure safe use of these active compounds as a therapeutic agent. Thus, this paper reviews the active antioxidative, antiproliferative, anti-inflammatory, or antiangiogenesis role of various phytochemicals for prevention of chronic diseases.

Atorvastatin calcium inhibits phenotypic modulation of PDGF-BB-induced VSMCs via down-regulation the Akt signaling pathway

Plasticity of vascular smooth muscle cells (VSMCs) plays a central role in the onset and progression of proliferative vascular diseases. In adult tissue, VSMCs exist in a physiological contractile-quiescent phenotype, which is defined by lack of the ability of proliferation and migration, while high expression of contractile marker proteins. After injury to the vessel, VSMC shifts from a contractile phenotype to a pathological synthetic phenotype, associated with increased proliferation, migration and matrix secretion. It has been demonstrated that PDGF-BB is a critical mediator of VSMCs phenotypic switch. Atorvastatin calcium, a selective inhibitor of 3-hydroxy-3-methyl-glutaryl l coenzyme A (HMG-CoA) reductase, exhibits various protective effects against VSMCs. In this study, we investigated the effects of atorvastatin calcium on phenotype modulation of PDGF-BB-induced VSMCs and the related intracellular signal transduction pathways. Treatment of VSMCs with atorvastatin calcium showed dose-dependent inhibition of PDGF-BB-induced proliferation. Atorvastatin calcium co-treatment inhibited the phenotype modulation and cytoskeleton rearrangements and improved the expression of contractile phenotype marker proteins such as α-SM actin, SM22α and calponin in comparison with PDGF-BB alone stimulated VSMCs. Although Akt phosphorylation was strongly elicited by PDGF-BB, Akt activation was attenuated when PDGF-BB was co-administrated with atorvastatin calcium. In conclusion, atorvastatin calcium inhibits phenotype modulation of PDGF-BB-induced VSMCs and activation of the Akt signaling pathway, indicating that Akt might play a vital role in the modulation of phenotype.

Use of dietary phytochemicals to target inflammation, fibrosis, proliferation, and angiogenesis in uterine tissues: promising options for prevention and treatment of uterine fibroids?

Uterine leiomyomas (fibroids, myomas) are the most common benign tumors of female reproductive tract. They are highly prevalent, with 70-80% of women burdened by the end of their reproductive years. Fibroids are a leading cause of pelvic pain, abnormal vaginal bleeding, pressure on the bladder, miscarriage, and infertility. They are the leading indication for hysterectomy, and costs exceed 6 billion dollars annually in the United States. Unfortunately, no long-term medical treatments are available. Dysregulation of inflammatory processes are thought to be involved in the initiation of leiomyoma and extracellular matrix deposition, cell proliferation, and angiogenesis are the key cellular events implicated in leiomyoma growth. In modern pharmaceutical industries, dietary phytochemicals are used as source of new potential drugs for many kinds of tumors. Dietary phytochemicals may exert therapeutic effects by interfering with key cellular events of the tumorigenesis process. At present, a negligible number of phytochemicals have been tested as therapeutic agents against fibroids. In this context, our aim was to introduce some of the potential dietary phytochemicals that have shown anti-inflammatory, antiproliferative, antifibrotic, and antiangiogenic activities in different biological systems. This review could be useful to stimulate the evaluation of these phytochemicals as possible therapies for uterine fibroids.

Resveratrol inhibits phenotype modulation by platelet derived growth factor-bb in rat aortic smooth muscle cells

Dedifferentiated vascular smooth muscle cells (VSMCs) are phenotypically modulated from the contractile state to the active synthetic state in the vessel wall. In this study, we investigated the effects of resveratrol on phenotype modulation by dedifferentiation and the intracellular signal transduction pathways of platelet derived growth factor-bb (PDGF-bb) in rat aortic vascular smooth muscle cells (RAOSMCs). Treatment of RAOSMCs with resveratrol showed dose-dependent inhibition of PDGF-bb-stimulated proliferation. Resveratrol treatment inhibited this phenotype change and disassembly of actin filaments and maintained the expression of contractile phenotype-related proteins such as calponin and smooth muscle actin-alpha in comparison with only PDGF-bb stimulated RAOSMC. Although PDGF stimulation elicited strong and detectable Akt and mTOR phosphorylations lasting for several hours, Akt activation was much weaker when PDGF was used with resveratrol. In contrast, resveratrol only slightly inhibited phosphorylations of 42/44 MAPK and p38 MAPK. In conclusion, RAOSMC dedifferentiation, phenotype, and proliferation rate were inhibited by resveratrol via interruption of the balance of Akt, 42/44MAPK, and p38MAPK pathway activation stimulated by PDGF-bb.

Regulation of fibrillar collagen-mediated smooth muscle cell proliferation in response to chemical stimuli by telomere reverse transcriptase through c-Myc

Human telomerase reverse transcriptase (hTERT) and oncogene c-Myc have been shown to regulate cell proliferation. Our previous studies demonstrated that fibrillar collagen mediates vascular smooth muscle cell (SMC) cycle progression and proliferation in response to platelet-derived growth factor (PDGF)-BB and interleukin (IL)-1β. However, whether hTERT and c-Myc are involved in these fibrillar collagen-mediated SMC responses remain unclear. The present study elucidated the regulatory role of hTERT and c-Myc in PDGF-BB/IL-1β-induced cell cycle progression in SMCs on fibrillar collagen and its underlying mechanisms. Our results showed that PDGF-BB and IL-1β exert synergistic effects to induce hTERT expression, but not its activity, in human arterial SMCs on fibrillar collagen. This PDGF-BB/IL-1β-induced up-regulation of hTERT contributes to cell cycle progression in SMCs through the up-regulation of cyclin-dependent kinase-6 and down-regulations of p27(KIP1) and p21(CIP1). In addition, PDGF-BB/IL-1β induces up-regulation of c-Myc in SMCs on fibrillar collagen; this response is mediated by the increased binding of hTERT, which can form complexes with TPP1 and hnRNPK, to the guanine-rich region of the c-Myc promoter and consequently contributes to cell cycle progression in SMCs on fibrillar collagen. Moreover, the PDGF-BB/IL-1β-induced hTERT and c-Myc expressions are regulated by phosphatidylinositol 3-kinase/Akt in SMCs on fibrillar collagen. Our findings provide insights into the mechanisms by which hTERT and c-Myc regulates SMC cell cycle progression and proliferation on fibrillar collagen in response to chemical stimuli.