Anthocyanin extracted from Hibiscus attenuate oxidized LDL-mediated foam cell formation involving regulation of CD36 gene

Stabilization of Anthocyanins from Coffee (Coffea arabica L.) Husks and In Vivo Evaluation of Their Antioxidant Activity

Coffee (Coffea arabica L.) is one of the most popular and widely consumed products throughout the world, mainly due to its taste, aroma, caffeine content, and natural antioxidants. Among those antioxidants, anthocyanins are one of the most important natural pigments, which can be found in coffee husks. It is widely known that anthocyanins have multiple health benefits partially linked to their antioxidant properties. However, anthocyanins have low stability and are sensitive to all types of changes. In order to prevent its degradation, anthocyanins can be stabilized with nanoparticles. Thus, the main objective of this study was to evaluate the stability of the anthocyanins extracted from coffee husks, using three different extracting agents (ethanol, methanol, and water) and stabilizing them through conjugation with zinc oxide nanoparticles. The anthocyanins extracts were mainly composed of cyanidin-3-rutinoside (97%) and the total phenolic compounds of the fresh extracts were 458.97 ± 11.32 (methanol), 373.53 ± 12.74 (ethanol), and 369.85 ± 15.93 (water) mg GAE/g. On the other hand, the total phenolic compounds of the nanoparticle-anthocyanin conjugates underwent no significant changes after stabilization as the major loss was less than 3%. Furthermore, the percentage of anthocyanins' degradation was less than 5% after 12 weeks of storage. On top of that, fresh anthocyanin extracts and anthocyanin-nanoparticle conjugates exhibited a strong protective effect against oxidative stress and increased the survival rate of Caenorhabditis elegans.

Anthocyanins as Key Phytochemicals Acting for the Prevention of Metabolic Diseases: An Overview

Anthocyanins are water-soluble pigments present in fruits and vegetables, which render them an extensive range of colors. They have a wide distribution in the human diet, are innocuous, and, based on numerous studies, have supposed preventive and therapeutical benefits against chronic affections such as inflammatory, neurological, cardiovascular, digestive disorders, diabetes, and cancer, mostly due to their antioxidant action. Despite their great potential as pharmaceutical applications, they have a rather limited use because of their rather low stability to environmental variations. Their absorption was noticed to occur best in the stomach and small intestine, but the pH fluctuation of the digestive system impacts their rapid degradation. Urine excretion and tissue distribution also occur at low rates. The aim of this review is to highlight the chemical characteristics of anthocyanins and emphasize their weaknesses regarding bioavailability. It also targets to deliver an update on the recent advances in the involvement of anthocyanins in different pathologies with a focus on in vivo, in vitro, animal, and human clinical trials.

Antioxidant properties of anthocyanins and their mechanism of action in atherosclerosis

Atherosclerosis develops due to lipid accumulation in the arterial wall and sclerosis as result of increased hyperlipidemia, oxidative stress, lipid oxidation, and protein oxidation. However, improving antioxidant status through diet may prevent the progression of atherosclerotic cardiovascular disease. It is believed that polyphenol-rich plants contribute to the inverse relationship between fruit and vegetable intake and chronic disease. Anthocyanins are flavonoid polyphenols with antioxidant properties that have been associated with reduced risk of cardiovascular disease. The consumption of anthocyanins increases total antioxidant capacity, antioxidant defense enzymes, and HDL antioxidant properties by several measures in preclinical and clinical populations. Anthocyanins appear to impart antioxidant actions via direct antioxidant properties, as well as indirectly via inducing intracellular Nrf2 activation and antioxidant gene expression. These actions counter oxidative stress and inflammatory signaling in cells present in atherosclerotic plaques, including macrophages and endothelial cells. Overall, anthocyanins may protect against atherosclerosis and cardiovascular disease through their effects on cellular antioxidant status, oxidative stress, and inflammation; however, their underlying mechanisms of action appear to be complex and require further elucidation.

A Standardized Extract Prepared from Red Orange and Lemon Wastes Blocks High-Fat Diet-Induced Hyperglycemia and Hyperlipidemia in Mice

Citrus fruits are a rich source of high-value bioactive compounds and their consumption has been associated with beneficial effects on human health. Red (blood) oranges (Citrus sinensis L. Osbeck) are particularly rich in anthocyanins (95% of which are represented by cyanidin-3-glucoside and cyanidin-3-6″-malonyl-glucoside), flavanones (hesperidin, narirutin, and didymin), and hydroxycinnamic acids (caffeic acid, coumaric acid, sinapic, and ferulic acid). Lemon fruit (Citrus limon) is also rich in flavanones (eriocitrin, hesperidin, and diosmin) and other polyphenols. All of these compounds are believed to play a very important role as dietary antioxidants due to their ability to scavenge free radicals. A standardized powder extract, red orange and lemon extract (RLE), was obtained by properly mixing anthocyanins and other polyphenols recovered from red orange processing waste with eriocitrin and other flavanones recovered from lemon peel by a patented extraction process. RLE was used for in vivo assays aimed at testing a potential beneficial effect on glucose and lipid metabolism. In vivo experiments performed on male CD1 mice fed with a high-fat diet showed that an 8-week treatment with RLE was able to induce a significant reduction in glucose, cholesterol and triglycerides levels in the blood, with positive effects on regulation of hyperglycemia and lipid metabolism, thus suggesting a potential use of this new phytoextract for nutraceutical purposes.

The Impact of Anthocyanins and Iridoids on Transcription Factors Crucial for Lipid and Cholesterol Homeostasis

Nutrition determines our health, both directly and indirectly. Consumed foods affect the functioning of individual organs as well as entire systems, e.g., the cardiovascular system. There are many different diets, but universal guidelines for proper nutrition are provided in the WHO healthy eating pyramid. According to the latest version, plant products should form the basis of our diet. Many groups of plant compounds with a beneficial effect on human health have been described. Such groups include anthocyanins and iridoids, for which it has been proven that their consumption may lead to, inter alia, antioxidant, cholesterol and lipid-lowering, anti-obesity and anti-diabetic effects. Transcription factors directly affect a number of parameters of cell functions and cellular metabolism. In the context of lipid and cholesterol metabolism, five particularly important transcription factors can be distinguished: liver X receptor (LXR), peroxisome proliferator-activated receptor-α (PPAR-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer binding protein α (C/EBPα) and sterol regulatory element-binding protein 1c (SREBP-1c). Both anthocyanins and iridoids may alter the expression of these transcription factors. The aim of this review is to collect and systematize knowledge about the impact of anthocyanins and iridoids on transcription factors crucial for lipid and cholesterol homeostasis.

Black mulberry ethanol extract attenuates atherosclerosis-related inflammatory factors and downregulates PPARγ and CD36 genes in experimental atherosclerotic rats

Atherosclerosis (AS) is the pathological basis of various vascular diseases and currently is seriously affecting human health. Numerous studies have paid more attention to natural medicines with anti-AS properties. As a traditional Uygur folk medicine, black mulberry fruits are conventionally used in the prevention and treatment of cardiovascular diseases in southern Xinjiang of China, and their underlying mechanisms remain unknown. Our previous study revealed that the ethanol extract of black mulberry (EEBM) inhibited AS development by improving lipid metabolism abnormalities, enhancing anti-oxidative activities, and reducing atherosclerotic lesions of atherosclerotic rats. Based on this, our objective was to further investigate the effects of EEBM on the expression of AS-related inflammatory factors and the key genes PPARγ and CD36 of the ox-LDL-PPARγ-CD36 feed-forward cycle in experimental atherosclerotic rats. Black mulberry fruits were extracted with acid ethanol and chromatographed on an AB-8 macroporous resin to obtain EEBM. All experimental rats were randomly divided into five groups: normal, model, model plus simvastatin (5 mg/kg d·body weight), and model plus low-dose and high-dose EEBM groups (105 and 210 mg/kg d·body weight, respectively). Serum levels of the inflammatory factors were determined by enzyme-linked immunosorbent assay (ELISA). The mRNA and protein expression of PPARγ and CD36 in atherosclerotic rats' liver tissue and thoracic aorta were determined by Q-PCR and western blot analysis, respectively. EEBM at high dose effectively attenuated the abnormally expressed AS-related inflammatory factors of TNF-α, IL-6, MMP-9, and CRP in atherosclerotic rats by 41.5%, 66.1%, 77.5%, and 79.5%, respectively. After treatment with high dose EEBM, the elevated-expressions of PPARγ and CD36 at the mRNA and protein levels in atherosclerotic rats were found to be obviously downregulated at both levels. These results demonstrate that EEBM might lessen the AS-related inflammatory reaction, and then inhibit the formation of ox-LDL, consequently downregulating the expression of PPARγ and CD36 at the mRNA and protein levels, thus reducing macrophage-foam-cell formation and prohibiting the development of atherosclerotic plaque through the ox-LDL-PPARγ-CD36 feed-forward cycle, which can effectively prevent the occurrence and development of AS in atherosclerotic rats.

Mechanisms of Action of Nutritionally Rich Hibiscus sabdariffa's Therapeutic Uses in Major Common Chronic Diseases: A Literature Review

Hibiscus sabdariffa, this beverage has been used for millennia as both a delicious cultural beverage and an ancient medicinal therapy. In recent years, many studies have investigated the uses and mechanisms of action of Hibiscus sabdariffa to treat common chronic diseases. In this literature review, we place the spotlight on Hibiscus sabdariffa's medical effect on common chronic diseases, the flower commonly used to make hibiscus tea. The databases PubMed, MEDLINE, Clinical Key, and CINAHL were searched for studies related to Hibiscus sabdariffa's compounds, antioxidative and anti-inflammatory features, mechanism of action on common chronic diseases including hypertension, hyperlipidemia, obesity, diabetes, and Alzheimer's disease. Hibiscus sabdariffa antihypertensive potentials originate from the vasodilator activity, diuretic efficacy, functionality as an ACE inhibitor, adipocyte differentiation inhibitor, heart rate reduction ability, and anti-inflammatory mechanistic. The antihyperlipidemic effect is dose-dependent and stems from the antioxidative effect and the activation of AMPK through phosphorylation and the inhibition of regulatory adipogenic transcription factors PPAR-γ, C/EBP-α, and SREBP-1c, which altogether results in lipid-lowering effect. As an antihyperglycemic, Hibiscus sabdariffa serves as anti-insulin resistance by inhibition of the phosphorylation of IRS-1 beside a similar effect to gliptins. Finally, Hibiscus sabdariffa was proven to protect against neuroinflammation in microglial cell culture exposed to LPS by decreasing IL-1, IL-6, TNF-α expression, and the protective effect against glucotoxicity, improve memory function by inhibiting the formation of hyperphosphorylated tau proteins in the mouse brain. Regular consumption of hibiscus tea or extract is beneficial for a reduction in chronic disease risk and diagnosis. Key teaching pointsHibiscus sabdariffa, or hibiscus, has been used for millennia as both a delicious cultural beverage and an ancient medicinal therapy. Recent studies have investigated the uses of Hibiscus sabdariffa to treat common chronic diseases.Its antihypertensive potential originates from the vasodilator activity, diuretic efficacy, functionality as an ACE inhibitor, adipocyte differentiation inhibitor, heart rate reduction ability, and anti-inflammatory mechanistics.The antihyperlipidemic effect is dose-dependent and stems from the antioxidative effect and the activation of AMPK through phosphorylation and also the inhibition of regulatory adipogenic transcription factors PPAR-γ, C/EBP-α and SREBP-1c which all together results in lipid-lowering effect.As an antihyperglycemic, Hibiscus sabdariffa serves as anti-insulin resistance by inhibition of the phosphorylation of IRS-1 beside the similar effect to gliptins.Hibiscus sabdariffa was proven to protect against neuroinflammation in microglial cell culture exposed to LPS by decreasing IL-1, IL-6, TNF-α expression, and the protective effect against glucotoxicity, improve memory function by inhibiting the formation of hyperphosphorylated tau proteins in the mouse brain.

Protective effect of hydrogen sulfide on endothelial cells through Sirt1-FoxO1-mediated autophagy

Background

As a new member of the vasculoprotective gasotransmitter family, hydrogen sulfide (H₂S) functions similar to nitric oxide (NO) and carbon monoxide (CO). Endothelial cell (EC) death and autophagy enable cells to cope with the progression of cardiovascular diseases. However, the impacts and underlying mechanisms of H₂S in the autophagic process in ECs are not completely understood. Here, we investigated the effects of H₂S on autophagy in human vascular ECs.

Methods

Human umbilical vein endothelial cells (HUVECs) were exposed to different concentrations (0, 50, 100, 200, 500 and 1,000 µmol/L) GYY4137 (H₂S donor) for indicated times (0, 0.5, 1, 2, 4 and 8 h), with or without pre-treatment with the autophagy inhibitor 3-methyladenine (3-MA) or bafilomycin A1. HUVECs were transfected with sirtuin 1 (Sirt1) overexpression plasmids (PIRES-Sirt1), Sirt1-siRNAs or forkhead box O1 (FoxO1)-siRNA using Lipofectamine 2000. Cell autophagy was evaluated via Western blotting and fluorescence microscopy. Co-immunoprecipitation assay was used to measure acetylation level of FoxO1. The distribution of FoxO1 in the cytoplasm and nucleus was observed using Western blotting and immunofluorescence. Western blotting, flow cytometric analysis, and cell count kit-8 assay were conducted to evaluate the effect of H₂S on the oxidized low-density lipoprotein (Ox-LDL) induced apoptosis of HUVECs.

Results

Using both gain- and loss-of-function experiments, we showed that Sirt1-dependent activation of FoxO1, including its nuclear translocation and deacetylation, was critical for mediating H₂S-induced autophagy in ECs. Furthermore, H₂S-induced autophagy protected ECs from Ox-LDL-induced apoptosis by activating Sirt1.

Conclusions

These results suggest that Sirt1-mediated autophagy in ECs is a novel mechanism by which H₂S exerts vascular-protective actions.

Citrus reticulata peel oil as an antiatherogenic agent: Hypolipogenic effect in hepatic cells, lipid storage decrease in foam cells, and prevention of LDL oxidation

BACKGROUND AND AIMS

Hypercholesterolemia and oxidative stress are two of the most important risk factors for atherosclerosis. The aim of the present work was to evaluate mandarin (Citrus reticulata) peel oil (MPO) in cholesterol metabolism and lipid synthesis, and its antioxidant capacity.

METHODS AND RESULTS

Incubation of hepatic HepG2 cells with MPO (15-60 μL/L) reduced cholesterogenesis and saponifiable lipid synthesis, demonstrated by [¹⁴C]acetate radioactivity assays. These effects were associated with a decrease in a post-squalene reaction of the mevalonate pathway. Molecular docking analyses were carried out using three different scoring functions to examine the cholesterol-lowering property of all the components of MPO against lanosterol synthase. Docking simulations proposed that minor components of MPO monoterpenes, like alpha-farnesene and neryl acetate, as well the major component, limonene and its metabolites, could be partly responsible for the inhibitory effects observed in culture assays. MPO also decreased RAW 264.7 foam cell lipid storage and its CD36 expression, and prevented low-density lipoprotein (LDL) lipid peroxidation.

CONCLUSION

These results may imply a potential role of MPO in preventing atherosclerosis by a mechanism involving inhibition of lipid synthesis and storage and the decrease of LDL lipid peroxidation.

Anthocyanins and Human Health-A Focus on Oxidative Stress, Inflammation and Disease

Consumption of anthocyanins (ACNs), due to their antioxidant, anti-inflammatory and anti-apoptotic effects, has been proposed for the prevention and treatment of several different diseases and conditions. ACNs are recognized as one of the leading nutraceuticals for prolonging health benefits through the attenuation of oxidative stress, and inflammatory or age-related diseases. Increased consumption of ACNs has the potential to attenuate the damage ensuing from oxidative stress, inflammation, enhance cardiometabolic health, and delay symptoms in predisposed neuropathology. A myriad of evidence supports ACN consumption as complementary or standalone treatment strategies for non-communicable diseases (NCDs) including obesity, diabetes, cardiovascular disease (CVD), neurodegenerative diseases, as well as, more recently, for the modulation of gut bacteria and bone metabolism. While these findings indicate the beneficial effects of ACN consumption, their food sources differ vastly in ACN composition and thus potentially in their physiological effects. Consumption of foods high in ACNs can be recommended for their potential beneficial health effects due to their relatively easy and accessible addition to the everyday diet.

Oleanolic acid protects against pathogenesis of atherosclerosis, possibly via FXR-mediated angiotensin (Ang)-(1-7) upregulation

Atherosclerosis, the leading cause of cardiovascular diseases in the world, is a chronic inflammatory disorder characterized by the dysfunction of arteries. Oleanolic acid (OA) is a bioactive nature product which exists in various plants and herbs. Previous studies have demonstrated that OA was involved in numerous of biological processes, including atherosclerosis. However, the exact mechanisms of the anti-atherosclerosis effects of OA remain unknown. Here, in our study, we analyzed the effects and possible underlying mechanisms of OA in atherosclerosis depending a cell model and an animal model of atherosclerosis. Human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL, 100 μg/mL) for 24 h to establish an atherosclerotic cell model. New Zealand white (NZW) rabbits were fed with high-fat (HF) diets for three months to establish an atherosclerotic animal model. Then, cell viability and expression of cytokines (ANG, NO, eNOS, IL-1β, TNF-α, and IL-6) were measured with CCK-8 assay and ELISA kits, cell apoptosis and cell cycle distribution were analyzed by flow cytometry in the atherosclerotic cell model. Results showed that ox-LDL induced effects of anti-proliferation, cytokines alterations, and cell apoptosis were abolished by the application of OA or Ang (1-7). Further study indicated that OA increased the expression of ANG by upregulating the FXR expression in the ox-LDL induced HUVECs arthrosclerosis model. And the in vivo experiment in the HF diet induced animal model suggested that OA may inhibit the development of atherosclerosis. The atherosclerosis of aortas was assessed by Hematoxylin Eosin (HE), Oil Red O and Picrosirius Red staining; the expression levels of total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), and high density lipoprotein cholesterol (HDL-C) were determined by the fully automatic biochemical analyzer, in the atherosclerotic animal model. All the results showed that OA treatment improved the cell viability in the cell model, inhibited the atherosclerosis development in the animal model. OA play as an anti-atherosclerosis agent in both the cell model and animal model by upregulating the production of Angiotensin (Ang)-(1-7) through FXR.

Ethnomedicinal, Phytochemical and Ethnopharmacological Aspects of Four Medicinal Plants of Malvaceae Used in Indian Traditional Medicines: A Review

The ethnomedicinal values of plants form the basis of the herbal drug industry. India has contributed its knowledge of traditional system medicines (Ayurveda and Siddha) to develop herbal medicines with negligible side effects. The World Health Organization has also recognized the benefits of drugs developed from natural products. Abutilon indicum, Hibiscus sabdariffa, Sida acuta and Sida rhombifolia are ethnomedicinal plants of Malvaceae, commonly used in Indian traditional system of medicines. Traditionally these plants were used in the form of extracts/powder/paste by tribal populations of India for treating common ailments like cough and cold, fever, stomach, kidney and liver disorders, pains, inflammations, wounds, etc. The present review is an overview of phytochemistry and ethnopharmacological studies that support many of the traditional ethnomedicinal uses of these plants. Many phytoconstituents have been isolated from the four ethnomedicinal plants and some of them have shown pharmacological activities that have been demonstrated by in vivo and/or in vitro experiments. Ethnomedicinal uses, supported by scientific evidences is essential for ensuring safe and effective utilization of herbal medicines.

Health benefits of anthocyanins and molecular mechanisms: Update from recent decade

Anthocyanins are one of the most widespread families of natural pigments in the plant kingdom. Their health beneficial effects have been documented in many in vivo and in vitro studies. This review summarizes the most recent literature regarding the health benefits of anthocyanins and their molecular mechanisms. It appears that several signaling pathways, including mitogen-activated protein kinase, nuclear factor κB, AMP-activated protein kinase, and Wnt/β-catenin, as well as some crucial cellular processes, such as cell cycle, apoptosis, autophagy, and biochemical metabolism, are involved in these beneficial effects and may provide potential therapeutic targets and strategies for the improvement of a wide range of diseases in future. In addition, specific anthocyanin metabolites contributing to the observed in vivo biological activities, structure-activity relationships as well as additive and synergistic efficacy of anthocyanins are also discussed.

SIRT1/Atg5/autophagy are involved in the antiatherosclerosis effects of ursolic acid

The purpose of this study was to investigate the antiatherosclerosis effects of ursolic acid (UA) in high-fat diet-fed quails (Coturnix coturnix) and potential mechanism. Quails were treated with high-fat diet (14 % pork oil, 1 % cholesterol w/w) with or without UA (50, 150, or 300 mg/kg/day) for 10 weeks. Serum lipid profile was assessed at 0, 4.5, and 10 weeks. After 10 weeks, serum antioxidant status and morphology of aorta were assessed. Additionally, human umbilical vein endothelial cells (HUVECs) were exposed to 100 μg/ml oxidized low-density lipoprotein (ox-LDL) for 24 h, with or without pretreatment with UA (5, 10 or 20 μM) for 16 h, autophagy inhibitor 3-MA 5 mM for 2 h, or SIRT1 inhibitor EX-527 10 μM for 2 h. Cell viability and oxidative stress status were assessed and autophagy status was determined. Acetylation of lysine residue on Atg5 was assessed with immunoprecipitation. In results, high-fat diet negatively affected serum lipid profile and antioxidant status in quails and induced significant histological changes. Cotreatment with UA remarkably alleviated such changes. In HUVECs, ox-LDL treatment induced significant cytotoxicity along with oxidative stress, while UA cotreatment alleviated such changes significantly. UA treatment induced autophagy, enhanced SIRT1 expression, and decreased acetylation of lysine residue on Atg5. Cotreatment with 3-MA or EX-527 effectively abolished UA's protective effects. In summary, UA exerted antiatherosclerosis effects in quails and protected HUVECs from ox-LDL induced cytotoxicity, and the mechanism is associated with increased SIRT1 expression, decreased Atg5 acetylation on lysine residue, and increased autophagy.

Pomegranate peel polyphenols inhibit lipid accumulation and enhance cholesterol efflux in raw264.7 macrophages

Pomegranate peel polyphenols hindered ox-LDL-induced raw264.7 foam cell formation, by decreasing CD36 and promoting ABCA1 and LXRα expression.

Modulation of oxidized-LDL receptor-1 (LOX1) contributes to the antiatherosclerosis effect of oleanolic acid

Oleanolic acid (OA) is a bioactive pentacyclic triterpenoid. The current work studied the effects and possible mechanisms of OA in atherosclerosis. Quails (Coturnix coturnix) were treated with high fat diet with or without OA. Atherosclerosis was assessed by examining lipid profile, antioxidant status and histology in serum and aorta. Human umbilical vein endothelial cells (HUVECs) were exposed to 200μg/mL ox-LDL for 24h, then cell viability was assessed with MTT assay; reactive oxygen species (ROS) was assessed with DCFDA staining. Expression levels of LOX-1, NADPH oxidase subunits, nrf2 and ho-1 were measured with real time PCR and western blotting. Furthermore, LOX-1 was silenced with lentivirus and the expression levels assessment was repeated. OA treatment improved the lipid profile and antioxidant status in quails fed with high fat diet. Histology showed decreased atherosclerosis in OA treated animals. Ox-LDL exposure decreased viability and induced ROS generation in HUVECs, and this progression was alleviated by OA pretreatment. Moreover, elevated expression of LOX-1, NADPH oxidase subunits, nrf2 and ho-1 were observed in ox-LDL exposed HUVECs. OA pretreatment prevented ox-LDL induced increase of LOX-1 and NADPH oxidase subunits expression, while further increased nrf2 and ho-1 expression. Silencing of LOX-1 abolished ox-LDL induced effects in cell viability, ROS generation and gene expression. OA could alleviate high fat diet induced atherosclerosis in quail and ox-LDL induced cytotoxicity in HUVECs; the potential mechanism involves modulation of LOX-1 activity, including inhibition of expression of NADPH oxidase subunits and increase of the expression of nrf2 and ho-1.

An anthocyanin-rich extract from Hibiscus sabdariffa linnaeus inhibits N-nitrosomethylurea-induced leukemia in rats

A previous study reported that anthocyanins from roselle (Hibiscus sabdariffa L.) showed significant anticancer activity in human promyelocytic leukemia cells. To explore the antitumor effect of anthocyanin, a roselle bioactive polyphenol in a rat model of chemical-induced leukemia was assayed. Anthocyanin extract of roselle (Hibiscus anthocyanins, HAs) was supplemented in the diet (0.1 and 0.2%). This study was carried out to evaluate the protective effect of HAs on N-nitrosomethylurea (NMU)-induced leukemia of rats. The study employed male Sprague-Dawley rats (n = 48), and leukemia was induced by intravenous injection of 35 mg kg(-1) body weight of NMU dissolved in physiologic saline solution. The rats were divided into four groups (n = 12): control, NMU only, and HAs groups that received different doses of HAs (0.1 and 0.2%) daily, orally, after NMU injection. After 220 days, the animals were killed, and the following parameters were assessed: morphological observation, hematology examination, histopathological assessment, and biochemical assay. When compared with the NMU-only group, HAs significantly prevented loss of organ weight and ameliorated the impairment of morphology, hematology, and histopathology. Treatment with HAs caused reduction in the levels of AST, ALT, uric acid, and MPO. Also, the results showed that oral administration of HAs (0.2%) remarkably inhibited progression of NMU-induced leukemia by approximately 33.3% in rats. This is the first report to demonstrate that the sequential administration of HAs followed by NMU resulted in an antileukemic activity in vivo.

Effect of Hibiscus sabdariffa Calices on Dyslipidemia in Obese Adolescents: A Triple-masked Randomized Controlled Trial

CONFLICT OF INTEREST

none declared.

OBJECTIVE

We aimed to evaluate the effects of Hibiscus sabdariffa (HS) calices on controlling dyslipidemia in obese adolescents.

METHODOLOGY

In this triple blind randomized placebo-controlled clinical trial which was registered in the Iranian registry for clinical trials (IRCT201109122306N2), 90 obese adolescents aged 12-18 years with documented dyslipidemia were randomly assigned in two groups of cases who received 2 grams of fine powdered calices of Hibiscus sabdariffa per day for one month and controls who received placebo powder with the same dietary and physical activity recommendations and duration of exposure. Full lipid profile and fasting blood sugar measured before and after the trial. Data were analyzed using multivariate general linear model.

FINDINGS

Overall, 72 participants (mean age of 14.21±1.6, 35 boys) completed the trial. The two arms of the study (cases and controls) were not statistically different in terms of age, gender, weight, body mass index (BMI) and lipid profile before the trial. Serum total cholesterol, low density lipoprotein cholesterol and serum triglyceride showed a significant decrease in cases group but high density lipoprotein cholesterol level was not changed significantly.

CONCLUSION

It is concluded that Hibiscus sabdariffa calyces powder may have significant positive effects on lipid profile of adolescents which maybe attributed to its polyphenolic and antioxidant content. Further studies are needed on dose-response and formulation optimization.

Supplementation of cyanidin-3-O-β-glucoside promotes endothelial repair and prevents enhanced atherogenesis in diabetic apolipoprotein E-deficient mice

Atherosclerosis is accelerated in diabetes mellitus mainly due to the reduced availability and function of endothelial progenitor cells (EPCs). The purpose of this study was to determine the protective effects of the anthocyanin cyanidin-3-O-β-glucoside (C3G) on EPC function and endothelial repair in diabetic apolipoprotein E-deficient (apoE(-/-)) mice. Diabetes mellitus was induced in 8-wk-old male apoE(-/-) mice with streptozotocin. Diabetic apoE(-/-) mice were fed the AIN-93 diet or an AIN-93 diet supplemented with C3G (0.2% wt:wt) for 6 wk. Sham-injected apoE(-/-) mice fed the AIN-93 diet served as nondiabetic controls. The endothelium-dependent relaxation response to acetylcholine in the aortas of C3G-fed mice was greater by 51% compared with diabetic mice fed the AIN-93 diet (P < 0.05) and was similar to that in nondiabetic apoE(-/-) mice. The capacity of in vitro adhesion to fibronectin, migration, and tube formation was significantly impaired in diabetic EPCs (decreased by 83, 61.9, and 74.5%, respectively, compared with nondiabetic controls; all P < 0.01), which was significantly rescued in response to C3G (increased by 3.9-, 2-, and 1.8-fold compared with diabetic EPCs, respectively; all P < 0.05). At the molecular level, the phosphorylation levels of AMP-activated protein kinase (AMPK) Thr 172 and endothelial nitric oxide synthase (eNOS) Ser1177 were higher in EPCs derived from the C3G-treated diabetic mice compared with those in nondiabetic mice. Furthermore, compared with nondiabetic controls, diabetic apoE(-/-) mice had a 3.5-fold increase in the aortic lesion area, which was lowered by 45% in C3G-fed diabetic mice. This study extends our current knowledge that C3G improves the impairment of EPC function, enhances endothelial repair, and thus limits accelerated atherogenesis caused by diabetes. Our findings emphasize the potential utility of anthocyanin in the prevention and treatment of diabetic vascular complications.

Hibiscus sabdariffa L. in the treatment of hypertension and hyperlipidemia: a comprehensive review of animal and human studies

The effectiveness of Hibiscus sabdariffa L. (HS) in the treatment of risk factors associated with cardiovascular disease is assessed in this review by taking a comprehensive approach to interpreting the randomized clinical trial (RCT) results in the context of the available ethnomedical, phytochemical, pharmacological, and safety and toxicity information. HS decoctions and infusions of calyxes, and on occasion leaves, are used in at least 10 countries worldwide in the treatment of hypertension and hyperlipidemia with no reported adverse events or side effects. HS extracts have a low degree of toxicity with a LD50 ranging from 2,000 to over 5,000mg/kg/day. There is no evidence of hepatic or renal toxicity as the result of HS extract consumption, except for possible adverse hepatic effects at high doses. There is evidence that HS acts as a diuretic, however in most cases the extract did not significantly influence electrolyte levels. Animal studies have consistently shown that consumption of HS extract reduces blood pressure in a dose dependent manner. In RCTs, the daily consumption of a tea or extract produced from HS calyxes significantly lowered systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults with pre to moderate essential hypertension and type 2 diabetes. In addition, HS tea was as effective at lowering blood pressure as the commonly used blood pressure medication Captropril, but less effective than Lisinopril. Total cholesterol, low-density lipoprotein cholesterol (LDL-C), and triglycerides were lowered in the majority of normolipidemic, hyperlipidemic, and diabetic animal models, whereas high-density lipoprotein cholesterol (HDL-C) was generally not affected by the consumption of HS extract. Over half of the RCTs showed that daily consumption of HS tea or extracts had favorable influence on lipid profiles including reduced total cholesterol, LDL-C, triglycerides, as well as increased HDL-C. Anthocyanins found in abundance in HS calyxes are generally considered the phytochemicals responsible for the antihypertensive and hypocholesterolemic effects, however evidence has also been provided for the role of polyphenols and hibiscus acid. A number of potential mechanisms have been proposed to explain the hypotensive and anticholesterol effects, but the most common explanation is the antioxidant effects of the anthocyanins inhibition of LDL-C oxidation, which impedes atherosclerosis, an important cardiovascular risk factor. This comprehensive body of evidence suggests that extracts of HS are promising as a treatment of hypertension and hyperlipidemia, however more high quality animal and human studies informed by actual therapeutic practices are needed to provide recommendations for use that have the potential for widespread public health benefit.

Supplementation with cyanidin-3-O-β-glucoside protects against hypercholesterolemia-mediated endothelial dysfunction and attenuates atherosclerosis in apolipoprotein E-deficient mice

In this study, we investigated the protective effects of the anthocyanin cyanidin-3-O-β-glucoside (C3G) on hypercholesterolemia-induced endothelial dysfunction in apoE-deficient (apoE(-/-)) mice. In the prevention study, twenty 8-wk-old male apoE(-/-) mice (n = 10/group) were fed a high-fat, cholesterol-rich diet (HCD) or the HCD supplemented with C3G (2 g/kg diet) for 8 wk. The endothelium-dependent relaxation response to acetylcholine in the aortas of the C3G-fed mice was greater compared with those fed the HCD (P < 0.05). The atherosclerotic plaque area in the aortic sinus of mice fed the C3G diet was lowered by 54% compared with those fed the HCD (P < 0.01). Mice fed C3G had greater expression of the ATP-binding cassette transporter G1 (ABCG1) and lower cholesterol, mainly 7-ketocholesterol (7-KC), concentrations than those fed the HCD. Superoxide production and lipid hydroperoxides in aorta were lower in mice fed C3G compared with those fed the HCD. The phosphorylation levels at Ser1177 of endothelial NO synthase (eNOS) and the production of cyclic GMP (cGMP) in aorta were greater in C3G-fed mice than in HCD-fed mice. In the therapy study, apoE(-/-) mice were fed the HCD for 8 wk and then continued to receive the HCD or were switched to the HCD supplemented with C3G (2 g/kg diet) for another 8 wk. The established endothelial dysfunction and atherosclerosis were reversed, accompanied by greater ABCG1 expression in aorta, lower cholesterol and 7-KC concentrations, and greater generation of cGMP in mice fed C3G compared with those fed the HCD. Taken together, our results show that the anthocyanin C3G prevents or reverses hypercholesterolemia-induced endothelial dysfunction by inhibiting cholesterol and 7-oxysterol accumulation in the aorta and the subsequent decrease in superoxide production, thereby preserving eNOS activity and NO bioavailability.

N-acetyl cysteine suppresses the foam cell formation that is induced by oxidized low density lipoprotein via regulation of gene expression

Foam cells derived from macrophages have been implicated as markers of early stage atherosclerosis development. In this study, we found that N-acetyl cysteine (NAC), a well-known inhibitor of reactive oxygen species (ROS), decreased the generation of ROS and suppressed foam cell formation in the presence of oxidized low density lipoprotein through down-regulation of cluster of differentiation 36 expression. We investigated gene expression profiles in order to determine the effects of NAC on foam cell formation using a microarray analysis. The level of apolipoprotein E, which is involved in lipid efflux, was increased and the levels of the antioxidant genes glutathione peroxidase 1 and 3 were also increased. The expression levels of the oxidative stress response and the DNA repair genes were decreased. These results were confirmed using quantitative real-time PCR. Our results indicate that oxidative stress plays an important role in foam cell formation, and that regulation of oxidation using antioxidants is a potential therapeutic method for blocking atherosclerosis development.

Bilberry anthocyanin-rich extract alters expression of genes related to atherosclerosis development in aorta of apo E-deficient mice

Intake of anthocyanin-rich foods has been associated with a reduced risk of cardiovascular diseases. We recently reported that a nutritional supplementation with a bilberry anthocyanin-rich extract (BE) attenuates atherosclerotic lesion development in apolipoprotein E-deficient (apoE⁻/⁻) mice. However, the mechanism(s) of their preventive action are not completely understood. Anthocyanins may alter mRNA levels of genes related to atherosclerosis in cultured macrophages and endothelial cells, but in vivo studies remain scarce. The aim of the present study was to explore the in vivo mechanisms of action of the same bilberry extract, administered by supplementation at a nutritional level, in the aorta of apo E⁻/⁻ mice using a global transcriptomic approach. This study focused on the early stage of atherosclerosis development for better assessment of BE action on initiation mechanisms of this pathology. After a two week period, plasma lipid and antioxidant capacity were evaluated and the global genomic analysis was carried out using pangenomic microarrays. BE supplementation significantly improved hypercholesterolemia whereas the plasmatic antioxidant status remained unchanged. Nutrigenomic analysis identified 1261 genes which expression was modulated by BE in the aorta. Bioinformatic analysis revealed that these genes are implicated in different cellular processes such as oxidative stress, inflammation, transendothelial migration and angiogenesis, processes associated with atherosclerosis development/protection. Some of the most significantly down-regulated genes included genes coding for AOX1, CYP2E1 or TXNIP implicated in the regulation of oxidative stress, JAM-A coding for adhesion molecules or VEGFR2 implicate in regulation of angiogenesis. Other genes were up-regulated, such as CRB3, CLDN14 or CDH4 potentially associated with increased cell-cell adhesion and decreased paracellular permeability. These results provide a global integrated view of the mechanisms involved in the preventive action of bilberry anthocyanin-rich extract against atherosclerosis.

Whole grape intake impacts cardiac peroxisome proliferator-activated receptor and nuclear factor kappaB activity and cytokine expression in rats with diastolic dysfunction

Prolonged hypertension is the leading cause of heart failure. Failing hearts show reduced peroxisome proliferator-activating receptor (PPAR) activity and enhanced nuclear factor kappaB (NF-kappaB) activity, which together modify cardiac inflammation and fibrosis. In vitro studies suggest that phytochemicals alter PPAR and NF-kappaB activity, but the capabilities of a phytochemical-rich diet are less understood. Grapes contain an array of commonly consumed dietary phytochemicals. In Dahl salt-sensitive hypertensive rats, we showed previously that dietary provision of whole table grape powder (3% weight:weight) for 18 weeks reduced blood pressure, cardiac hypertrophy, and diastolic dysfunction. The hypothesis tested here is that, in this model, phytochemical provision from whole grape powder impacts cardiac PPAR and NF-kappaB activity and their related gene transcripts. Grape-fed rats had enhanced PPAR-alpha and PPAR-gamma DNA binding activity but reduced NF-kappaB DNA binding activity. RT-PCR revealed that grape-fed rats showed upregulated mRNA for PPAR-alpha, PPAR-gamma coactivator-1alpha, PPAR-gamma, and the cytosolic NF-kappaB inhibitor, inhibitor-kappaBalpha. By contrast, grape-fed rats showed downregulated mRNA for tumor necrosis factor-alpha and transforming growth factor-beta1. Finally, grape-fed rats showed significantly reduced cardiac tumor necrosis factor-alpha and transforming growth factor-beta protein expression, increased inhibitor-kappaBalpha expression, and reduced cardiac fibrosis. In the Dahl salt-sensitive rat, chronic intake of grapes altered cardiac transcripts related to PPAR and NF-kappaB that may be significant to the observed diet-associated cardioprotection.

Nutrigenomic analysis of the protective effects of bilberry anthocyanin-rich extract in apo E-deficient mice

Intake of anthocyanin-rich foods has been associated with a reduced risk of cardiovascular diseases. Supplementation with anthocyanin-rich extracts from black rice or purple sweet potato was reported to attenuate atherosclerotic lesion development in apolipoprotein E-deficient (apo E(-/-)) mice. However, the mechanism(s) of their preventive action are not completely understood. Previous studies revealed that anthocyanins altered mRNA levels of genes related to atherosclerosis in cultured macrophages and endothelial cells, but in vivo studies remain scarce. The aim of the study was to investigate the impact of bilberry anthocyanin-rich extract (BE) supplementation on gene expression in the liver of apo E(-/-) mice, the widely used model of atherosclerosis. The liver was chosen because it is the main site of lipid metabolism. Apo E(-/-) mice received for 2 weeks a standard diet supplemented with a nutritional dose of BE (0.02%). This study focused on the early stage of atherosclerosis development for better assessment of anthocyanin action on initiation mechanisms of this pathology. The results showed that a 2-week supplementation significantly reduced plasmatic total cholesterol and hepatic triglyceride levels, whereas the plasmatic antioxidant status remained unchanged. Transcriptional analysis, using microarrays, revealed that the expression of 2,289 genes was significantly altered. BE over-expressed genes involved in bile acid synthesis and cholesterol uptake into the liver and down-regulated the expression of pro-inflammatory genes. These results suggest an anti-atherogenic effect of BE through the regulation of cholesterol metabolism and liver inflammation and provide a global integrated view of the mechanisms involved in the preventive action of this extract.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s12263-010-0171-0) contains supplementary material, which is available to authorized users.

In vitro vasorelaxation mechanisms of bioactive compounds extracted from Hibiscus sabdariffa on rat thoracic aorta

BACKGROUND

In this study, we suggested characterizing the vasodilator effects and the phytochemical characteristics of a plant with food usage also used in traditional treatment of arterial high blood pressure in Senegal.

METHODS

Vascular effects of crude extract of dried and powdered calyces of Hibiscus sabdariffa were evaluated on isolated thoracic aorta of male Wistar rats on organ chambers. The crude extract was also enriched by liquid-liquid extraction. The various cyclohexane, dichloromethane, ethyl acetate, butanol extracts obtained as well as the residual marc were subjected to Sephadex LH-20 column chromatography. The different methanolic eluate fractions were then analyzed by Thin Layer (TLC) and High Performance Liquid Chromatography (HPLC) and their vascular effects also evaluated.

RESULTS

The H. Sabdariffa crude extract induced mainly endothelium-dependent relaxant effects. The endothelium-dependent relaxations result from NOS activation and those who not dependent to endothelium from activation of smooth muscle potassium channels. The phytochemical analysis revealed the presence of phenolic acids in the ethyl acetate extract and anthocyans in the butanolic extract. The biological efficiency of the various studied extracts, in term of vasorelaxant capacity, showed that: Butanol extract > Crude extract > Residual marc > Ethyl acetate extract. These results suggest that the strong activity of the butanolic extract is essentially due to the presence of anthocyans found in its fractions 43-67.

CONCLUSION

These results demonstrate the vasodilator potential of hibiscus sabdariffa and contribute to his valuation as therapeutic alternative.