Veratric acid ameliorates hyperlipidemia and oxidative stress in Wistar rats fed an atherogenic diet

Veratric acid alleviates liver ischemia/reperfusion injury by activating the Nrf2 signaling pathway

Oxidative stress following liver ischemia/reperfusion (I/R) is an important pathological mechanism responsible for liver injury. Veratric acid (VA) is a phenolic benzoic acid that has been reported to have antioxidant properties. However, whether VA has protective effects against liver I/R injury remains unclear. In the present study, a mouse liver I/R injury model was established. VA was administered intragastrically for one week before liver I/R. Biochemical indicators, histological analysis, cell apoptosis, oxidative stress, and pathway proteins were tested to evaluate the protective effects of VA on liver I/R injury. Furthermore, a mouse AML12 hepatocyte hypoxia/reoxygenation (H/R) model was used to explore the underlying mechanism. VA alleviated liver I/R injury, as manifested by decreased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, liver necrotic area, oxidative stress, and hepatocyte apoptosis. VA pretreatment increased the expression of Nrf2 and its downstream antioxidant proteins heme oxygenase-1 (HO-1) and NADPH quinone oxidoreductase 1 (NQO-1). In addition, VA pretreatment increased AML12 cell activity and decreased oxidative stress; it also decreased the apoptosis induced by H/R. Moreover, the protective effect of VA on hepatocytes was related to the activation of the Nrf2 signaling pathway, and to increases in the Nrf2, HO-1, and NQO-1 protein expression. The inhibition of Nrf2 with ML385 offseted VA-mediated protection in AML12 cells. In conclusion, these results suggest that VA protects the liver from oxidative stress and apoptosis induced by liver I/R injury by activating the Nrf2 signaling pathway.

Enzymatic Synthesis of O-Methylated Phenophospholipids by Lipase-Catalyzed Acidolysis of Egg-Yolk Phosphatidylcholine with Anisic and Veratric Acids

Lipase-catalyzed acidolysis reactions of egg-yolk phosphatidylcholine (PC) with anisic (ANISA) and veratric (VERA) acids were investigated to develop a biotechnological method for the production of corresponding biologically active O-methylated phenophospholipids. Screening experiments with four commercially available immobilized lipases indicated that the most effective biocatalyst for the incorporation of ANISA into phospholipids was Novozym 435. None of the tested enzymes were able to catalyze the synthesis of PC structured with VERA. The effects of different solvents, substrate molar ratios, temperature, enzyme loading, and time of the reaction on the process of incorporation of ANISA into the phospholipids were evaluated in the next step of the study. The mixture of toluene/chloroform in the ratio 9:1 (v/v) significantly increased the incorporation of ANISA into PC. The acidolysis reaction was carried out using the selected binary solvent system, 1/15 substrate molar ratio PC/ANISA, 30% (w/w) enzyme load, and temperature of 50 °C afforded after 72 h anisoylated lysophosphatidylcholine (ANISA-LPC) and anisoylated phosphatidylcholine (ANISA-PC) in isolated yields of 28.5% and 2.5% (w/w), respectively. This is the first study reporting the production of ANISA-LPC and ANISA-PC via a one-step enzymatic method, which is an environmentally friendly alternative to the chemical synthesis of these biologically active compounds.

Hyperlipidaemia and cardioprotection: Animal models for translational studies

Hyperlipidaemia is a well-established risk factor for cardiovascular diseases and therefore, many animal model have been developed to mimic the human abnormal elevation of blood lipid levels. In parallel, extensive research for the alleviation of ischaemia/reperfusion injury has revealed that hyperlipidaemia is a major co-morbidity that attenuates the cardioprotective effect of conditioning strategies (preconditioning, postconditioning and remote conditioning) and that of pharmacological interventions by interfering with cardioprotective signalling pathways. In the present review article, we summarize the existing data on animal models of hypercholesterolaemia (total, low density and HDL abnormalities) and hypertriglyceridaemia used in ischaemia/reperfusion injury and protection from it. We also provide recommendations on preclinical animal models to be used for translations of the cardioprotective strategies into clinical practice. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.23/issuetoc.

Protocatechuic Acid Ameliorated Palmitic-Acid-Induced Oxidative Damage in Endothelial Cells through Activating Endogenous Antioxidant Enzymes via an Adenosine-Monophosphate-Activated-Protein-Kinase-Dependent Pathway

Protocatechuic acid (PCA, 3,4-dihydroxybenzoic acid), the main metabolite of anthocyanins, is widely distributed in fruits and vegetables and has been reported to possess a strong antioxidant activity. Herein, we aimed to investigate the protective effect of PCA against high palmitic-acid (PA)-induced oxidative damage and the underling molecular mechanisms in human umbilical vein endothelial cells (HUVECs). PCA reduced the levels of intracellular reactive oxygen species and malondialdehyde and increased the activities of endogenous antioxidant enzymes, including superoxide dismutase, glutathione peroxidase 1, and heme oxygenase 1 (HO-1). Metabolomic analysis showed that PCA affected numerous metabolites, especially some of which were related with energy metabolism. PCA also upregulated the phosphorylation of adenosine-monophosphate-activated protein kinase (AMPK) at Thr¹⁷² through activating liver kinase B1 and then promoted the expression of p-Nrf2 and HO-1. Moreover, PCA reversed the decreased expression of peroxisome proliferator-activated receptor γ coactivator 1α and significantly increased the mitochondrial density. Collectively, these results demonstrated that PCA attenuated PA-induced oxidative damage in HUVECs via an AMPK-dependent pathway.

Synthesis, Characterization, and In Vitro Cancer Cell Growth Inhibition Evaluation of Novel Phosphatidylcholines with Anisic and Veratric Acids

Phenolic acids and its methoxy derivatives are known to induce caspase-mediated apoptosis activity and exhibit cytotoxic effect towards various cancer cell lines. However, their low stability and poor bioavailability in the human organism extensively restrict the utility of this group of compounds as anticancer and health-promoting agents. In this report, a series of eight novel phosphatidylcholines (3a-b, 5a-b, 7a-b, 8a-b) containing anisic or veratric acids (1a-b) at sn-1 and/or sn-2 positions were synthesized. The phenoylated phospholipids were obtained in good yields 28–66%. The structures of novel compounds were determined by their spectroscopic data. All synthesized compounds were evaluated for their antiproliferative activity towards six cancer cell lines and normal cell line Balb/3T3. Lipophilization of phenolcarboxylic acids significantly increased their anticancer properties. The asymmetrically substituted phenoylated phosphatidylcholines exhibited higher antiproliferative effect than free acids. Lysophosphatidylcholine (7b) effectively inhibited the proliferation of human leukaemia (MV4-11), breast (MCF-7), and colon (LoVo) cancer cell lines at concentrations of 9.5–20.7 µm and was from 19 to 38-fold more active than corresponding free veratric acid. The conjugation of anisic/veratric acids with the phosphatidylcholine have proved the anticancer potential of these phenolcarboxylic acids and showed that this type of lipophilization is an effective method for the production of active biomolecules.

Trigonelline inhibits intestinal microbial metabolism of choline and its associated cardiovascular risk

Gut microbiota based metabolism of choline produces trimethylamine (TMA) which is further converted to a pro-atherosclerotic metabolite, trimethylamine-N-oxide (TMAO) by flavin monooxygenase (FMO₃). Trigonelline from the plant Trigonella foenum-graecum has been reported for the treatment of CVD. Aim of the present study was to check the effect of trigonelline on the gut microbiota based conversion of TMA to TMAO. Trigonelline was isolated from hydroalcoholic extract of seeds of Trigonella foenum-graecum. The isolated trigonelline was characterized through TLC and UPLC-MS. Anaerobic microbe responsible for the metabolism of choline to TMA was isolated by culturing the human gut microbiota in choline enriched medium. The isolated bacteria was identified at molecular level based on PCR amplification of 1500bp of 16S rRNA gene sequence. Isolated FMO₃ was used for ex vivo conversion of TMA to TMAO. Further, we investigated the effect of trigonelline in isolated gut microbe based metabolism of choline, lipid profile and TMAO levels in mice with or without suppression of gut microbiota with antibiotics. Liquid-liquid purification and chromatographic analysis confirmed the trigonelline purity (87.26%) and which was also confirmed by mass spectroscopy with m/z 137.4 in positive ionization mode. A total of 30 anaerobic microbes responsible for TMA production were isolated and Citrobacter freundii was the superior among others for the production of TMA. In vitro culture of C. freundii in choline enriched medium supplemented with trigonelline resulted in significantly reduction TMA and followed by TMAO production. In ex vivo, a maximum of 85.3% TMAO production was reduced by trigonelline at concentration of about 300 μg/mL. Serum level of lipids and TMAO were significantly altered in choline fed animals with or without suppression of gut microbiota and this phenomenon was reversed upon the oral administration of trigonelline in a dose-dependent manner. This study demonstrates the effect of trigonelline on gut microbiota responsible for choline metabolism and this can be used as a model for evaluation of herbal drugs and its effect in gut microbiota prompted cardiovascular disorders.

Association of the Common Catalase Gene Polymorphism rs1001179 With Glycated Hemoglobin and Plasma Lipids in Hyperlipidemic Patients

Catalase represents perhaps the most effective antioxidant defense in the body under conditions of increased oxidative stress, and rs1001179 (CAT-262C >T) is its most extensively studied gene polymorphism. Using an established PCR-RFLP method for genotyping, we examined the association of rs1001179 with glycated hemoglobin (HbA1c) and plasma lipids using univariate analyses with age, sex, body mass index (BMI), smoking, and alcohol abuse as covariates, in a group of dyslipidemic patients from northern Greece. Our results suggest that the TT genotype is a risk factor for increased HbA1c and plasma triglycerides, and that this association is modulated by the BMI and/or age of the patients.

Polyphenols: Potential source of drugs for the treatment of ischaemic heart disease

Polyphenols, which are naturally present in plants, have been studied for their chemical and pharmacological properties. Polyphenols have been found to exhibit various bioactivities such as antioxidant, free radical scavenging and anti-inflammatory effects, in addition to regulating the intracellular free calcium levels. These bioactivities are related to the underlying mechanisms of ischaemic heart diseases. Pharmacological studies have proven polyphenols to be effective in treating cardiovascular diseases in various ways, particularly ischaemic heart diseases. Based on their mode of action, we propose that some polyphenols can be developed as drugs to treat ischaemic heart diseases. For this purpose, a strategy to evaluate the therapeutic value of drugs for ischaemic heart diseases is needed. Despite several advances in percutaneous coronary intervention (PCI), the incidence of myocardial infarction and deaths due to cardiovascular diseases has not decreased markedly in China. Due to their pleiotropic properties and structural diversity, polyphenols have been of great interest in pharmacology. In the present review, we summarize the pharmacological effects and mechanisms of polyphenols reported after 2000, and we analyse the benefits or druggability of these compounds for ischaemic heart diseases.

Silicon-Enriched Restructured Pork Affects the Lipoprotein Profile, VLDL Oxidation, and LDL Receptor Gene Expression in Aged Rats Fed an Atherogenic Diet

BACKGROUND

Research has shown that silicon can play an important role in protecting against degenerative diseases. Restructuring pork by partially disassembling meat permits the incorporation of active components with potential functional effects. However, there has been no research to date on the impact that silicon, as a functional ingredient in restructured pork (RP), has on lipoprotein composition, metabolism, and oxidation.

OBJECTIVE

This study was designed to evaluate the effect of silicon-enriched RP on lipemia, lipoprotein profile, and oxidation markers of aged rats fed high-fat, high-energy, cholesterol-enriched diets.

METHODS

RP samples similar to commercial sausages (16% protein and 22% fat, wt:wt) were prepared by mixing lean pork and lard alone or with silicon (1.3 g Si/kg fresh matter) under controlled conditions and then freeze-dried. Saturated fat-rich diets were designed by mixing 78.3% purified diet with 21.7% freeze-dried RP. Three groups composed of 8 aged male Wistar rats (1 y old) were fed for 8 wk a control RP (C) diet, a cholesterol-enriched RP (Chol-C) diet [C diet enriched with 1.26% cholesterol plus 0.25% cholic acid, or a cholesterol and silicon-enriched RP (Chol-Si) diet (same as the Chol-C diet but containing silicon)]. Plasma lipid concentrations, lipoprotein profile, the degree of VLDL oxidation, and LDL receptor gene (Ldlr) expression were tested.

RESULTS

Compared with the C diet, the Chol-C diet did not modify food intake or body weight but significantly increased (P < 0.05) plasma cholesterol (32%) and total lipids (19%), VLDL and intermediate density lipoprotein + LDL cholesterol (both >600%), total lipids and proteins (both >300%), and the degree of VLDL oxidation [conjugated dienes >250%; thiobarbituric acid-reactive substance (TBARS), 900%] and reduced Ldlr expression (64%) and liver arylesterase activity (54%). The Chol-Si diet partially normalized changes induced by the Chol-C diet. Compared with the Chol-C group, Chol-Si rats had lower VLDL compound concentrations (P < 0.001; e.g., 75% less VLDL cholesterol) and VLDL oxidation (65% less conjugated dienes and 85% less TBARS) but greater Ldlr expression (200%).

CONCLUSIONS

Silicon added to RP strongly counterbalanced the negative effect of high-cholesterol-ingestion, functioning as an active hypocholesterolemic, hypolipemic, and antioxidative dietary ingredient in aged rats.

Pharmacokinetics and tissue distributions of veratric acid after intravenous administration in rats

The present study was designed to investigate the pharmacokinetics and tissue distributions of veratric acid following intravenous administration in rats. The concentrations of veratric acid in rat plasma at various times after administrated at doses of 2.5, 5, and 10 mg·kg(-1) were quantified by HPLC. The tissue distributions of veratric acid at various times after a single intravenous dose of 2.5 mg·kg(-1) were also analyzed. The plasma pharmacokinetic parameters at the three doses were as follows: t(1/2), (86.23 ± 6.83), (72.66 ± 4.10) and (71.20 ± 2.90) min; C0, (11.10 ± 1.47), (23.67 ± 1.24) and (39.17 ± 3.90) μg·mL(-1); and AUC(0→∞), (1 240.90 ± 129.14), (2 273.84 ± 132.47) and (3 516.4 ± 403.37) min·μg·mL(-1), respectively. The compound was distributed into tissues rapidly and extensively after intravenous administration and was mainly distributed into the liver, heart and kidneys.

Protective effect of veratric acid on lipopolysaccharide-induced acute lung injury in mice

Veratric acid, a simple benzoic acid derived from plants and fruits, has been reported to exhibit antibacterial, anti-inflammatory and other important therapeutic activities. The aim of this study was to detect the effects of veratric acid on LPS-induced acute lung injury and to investigate the effects of veratric acid on NF-κB signaling pathway. Male BALB/c mice were pretreated with dexamethasone or veratric acid 1h before intranasal instillation of LPS. 7h after LPS administration, the myeloperoxidase in lung tissues, lung wet/dry weight ratio and inflammatory cells in the bronchoalveolar lavage fluid (BALF) were determined. The effects of veratric acid on pro-inflammatory cytokines and signal pathways were analyzed by enzyme-linked immunosorbent assay (ELISA) and Western blotting. The results showed that veratric acid inhibited LPS-induced TNF-α, IL-6 and IL-1β production in a dose dependent manner. It was also observed that veratric acid attenuated lung histopathologic changes. The wet/dry weight ratio of lungs and the number of total cells, neutrophils, macrophages in the BALF were all decreased. Furthermore, veratric acid inhibited the phosphorylation of NF-κB p65 and IκB. These results indicate that veratric acid inhibits NF-κB signaling pathways to attenuate inflammatory injury induced by LPS. Veratric acid may be a potential therapeutic reagent for acute lung injury treatment.