High-dose chlorogenic acid induces inflammation reactions and oxidative stress injury in rats without implication of mast cell degranulation

Screening and identification of reactive metabolic compounds of Cortex Periplocae based on glutathione capture-mass spectrometry

As a traditional Chinese medicine (TCM), Cortex Periplocae (CP) has a wide range of pharmacological effects, as well as toxic side effects. The main toxic components of it are cardiac glycosides, which tend to cause cardiotoxicity. Currently, it has also been reported in studies to cause hepatotoxicity, but it is not clear whether the hepatotoxicity is related to the toxicity caused by the reactive metabolites. This study aims to investigate the target components of CP that generate reactive metabolic toxicity. The fluorescent probe method was used to detect glutathione (GSH)-trapped reactive metabolites in a co-incubation system of CP extract with rat liver microsomes. Identification of GSH conjugates was performed by LC-MS/MS and that of the possible precursor components that produce reactive metabolites was conducted by UPLC-Q-TOF/MS. Cell viability assays were performed on HepG2 and L02 cells to determine the cytotoxicity of the target components. The findings of our study demonstrate that the extract derived from CP has the ability to generate metabolites that exhaust the intracellular GSH levels, resulting in the formation of GSH conjugates and subsequent cytotoxic effects. Through the utilization of the UPLC-Q-TOF/MS technique, we were able to accurately determine the molecular weight of the precursor compound in CP to be 355.1023. The primary evidence to determining the GSH conjugetes relies on the appearance of characteristic product ions resulting from central neutral loss (CNL) scanning of 129 Da and product scanning of m/z 660 in the positive MS/MS spectrum. Through analysis, it was ultimately ascertained that the presence of chlorogenic acid (CGA) and its isomers, namely neochlorogenic acid (NCGA) and cryptochlorogenic acid (CCGA), could lead to the production of GSH conjugates, resulting in cytotoxicity at elevated levels. Taking these findings into consideration, the underlying cause for the potential hepatotoxicity of CP was initially determined.

Chlorogenic Acid Intravesical Therapy Changes Acute Voiding Behavior of Systemic Lipopolysaccharide Inflammation-Induced Cystitis Bladder in Mice

This study explores the potential efficacy of chlorogenic acid (CGA) in mitigating lipopolysaccharide (LPS)-induced cystitis in a mice model. C57BL/6J mice were divided into four groups: normal control (NC), LPS, LPS + low CGA, and LPS + high CGA. Evaluation methods included cystometrogram (CMG), histopathological, western blot, and immunohistological analysis. In the LPS group, CMG revealed abnormal voiding behavior with increased micturition pressure, voided volume (VV), and decreased voided frequency. Low CGA treatment in LPS mice demonstrated improved micturition pressure and inter-contraction intervals (ICI). However, high CGA treatment exhibited prolonged ICI and increased VV, suggesting potential adverse effects. Histological analysis of LPS-treated mice displayed bladder inflammation and interstitial edema. Low CGA treatment reduced interstitial edema and bladder inflammation, confirmed by Masson's trichrome staining. Western blotting revealed increased cytokeratin 20 (K20) expression in the low CGA group, indicating structural abnormalities in the bladder umbrella layer after LPS administration. In conclusion, low CGA treatment positively impacted voiding behavior and decreased bladder edema and inflammation in the LPS-induced cystitis mice model, suggesting its potential as a supplement for inflammation cystitis prevention. However, high CGA treatment exhibited adverse effects, emphasizing the importance of dosage considerations in therapeutic applications.

Characterization and quality evaluation of QiXueShuFu Decoction based on fingerprint and ultra-performance liquid chromatography-quadrupole-orbitrap mass spectrometry

QiXueShuFu Decoction (QXSFD) modified from the Bazhen Decoction which was originally from the classic Ming Dynasty is a traditional folk formula that boosts the body's immune system. However, its ambiguous chemical components limited its quality control evaluation. In this study, ultra-performance liquid chromatography (UPLC) fingerprint combined with multivariate analysis was used to evaluate the quality of 15 batches of QXSFD, and UPLC quadrupole-orbitrap mass spectrometry was used to further examine the chemical components in QXSFD, after which representative compounds from each disassembled prescription were selected for comparison. Fifteen batches of samples had 33 common peaks in which 11 differential components could be used as a reference for subsequent quality control. One hundred forty-three components were identified from QXSFD. Saponins were mainly derived from the monarch, terpenes from the minister, and polysaccharides and glycosides from the assistant. In addition, quantitative assay revealed that the content of ferulic acid, chlorogenic acid, 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside and 3,6'-disinapoyl sucrose in the whole prescription were higher than the contents of each disassembled prescription. This is the first comprehensive quality report on the chemical components of QXSFD, which is important for pharmacodynamic material basis and quality control.

Chlorogenic acids: A pharmacological systematic review on their hepatoprotective effects

BACKGROUND

Liver diseases have a negative impact on global health and are a leading cause of death worldwide. Chlorogenic acids (CGAs), a family of esters formed between certain trans-cinnamic acids and quinic acid, are natural polyphenols abundant in coffee, tea, and a variety of traditional Chinese medicines (TCMs). They are reported to have good hepatoprotective effects against various liver diseases.

PURPOSE

This review aims to analyze the available literature on the hepatoprotective effect of CGAs, with particular emphasis on their mechanisms.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. PubMed and Web of Science databases were adopted to retrieve all relevant literature on CGAs for liver disease from 2013 to March 2023.

RESULTS

Research has indicated that CGAs play a crucial role in improving different types of liver diseases, including drug-induced liver injury (DILI), alcoholic liver disease (ALD), metabolic (dysfunction)-associated fatty liver disease (MAFLD), cholestatic liver disease (CLD), liver fibrosis, and liver cancer. CGAs display remarkable antioxidant and anti-inflammatory effects by activating erythroid 2-related factor 2 (Nrf2) and inhibiting toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathways. Some important molecules such as AMP-activated protein kinase (AMPK) and extracellular signal-regulated kinases 1 and 2 (ERK1/2), and other key physiological processes like intestinal barrier and gut microbiota have also been discovered to participate in CGAs-provided amelioration on various liver diseases.

CONCLUSION

In this review, different studies indicate that CGAs have an excellent protective effect against various liver diseases associated with various signaling pathways.

The Effect of Green Coffee Supplementation on Lipid Profile, Glycemic Indices, Inflammatory Biomarkers and Anthropometric Indices in Iranian Women With Polycystic Ovary Syndrome: A Randomized Clinical Trial

Polycystic ovary syndrome (PCOS) is a heterogeneous clinical syndrome. Recent studies examine different strategies to modulate its related complications. Chlorogenic acid, as a bioactive component of green coffee (GC), is known to have great health benefits. The present study aimed to determine the effect of GC on lipid profile, glycemic indices, and inflammatory biomarkers. Forty-four PCOS patients were enrolled in this randomized clinical trial of whom 34 have completed the study protocol. The intervention group (n = 17) received 400 mg of GC supplements, while the placebo group (n = 17) received the same amount of starch for six weeks. Then, glycemic indices, lipid profiles, and inflammatory parameters were measured. After the intervention period, no significant difference was shown in fasting blood sugar, insulin level, Homeostasis model assessment of insulin resistance index, low-density lipoprotein, high-density lipoprotein, Interleukin 6 or 10 between supplementation and placebo groups. However, cholesterol and triglyceride serum levels decreased significantly in the intervention group (p < 0.05). This research confirmed that GC supplements might improve some lipid profiles in women with PCOS. However, more detailed studies with larger sample sizes are required to prove the effectiveness of this supplement.

Hypericum lanceolatum Lam. Medicinal Plant: Potential Toxicity and Therapeutic Effects Based on a Zebrafish Model

Hypericum lanceolatum Lam. (H. lanceolatum) is a traditional medicinal plant from Reunion Island used for its pleiotropic effects mainly related to its antioxidant activity. The present work aimed to 1) determine the potential toxicity of the plant aqueous extract in vivo and 2) investigate its putative biological properties using several zebrafish models of oxidative stress, regeneration, estrogenicity, neurogenesis and metabolic disorders. First, we characterized the polyphenolic composition by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and identified chlorogenic acid isomers, quercetin and kaempferol derivatives as the major compounds. We then evaluated for the first time the toxicity of an aqueous extract of H. lanceolatum and determined a maximum non-toxic concentration (MNTC) in zebrafish eleutheroembryos from 0 to 96 hpf following OECD (Organization for Economic Cooperation and Development) guidelines. This MNTC test was also determined on hatched eleutheroembryos after 2 days of treatment (from 3 to 5 dpf). In our study, the anti-estrogenic effects of H. lanceolatum are supported by the data from the EASZY assay. In a tail amputation model, we showed that H. lanceolatum at its MNTC displays antioxidant properties, favors immune cell recruitment and tissue regeneration. Our results also highlighted its beneficial effects in metabolic disorders. Indeed, H. lanceolatum efficiently reduces lipid accumulation and body mass index in overfed larva- and adult-models, respectively. In addition, we show that H. lanceolatum did not improve fasting blood glucose levels in a hyperglycemic zebrafish model but surprisingly inhibited neurogenesis impairment observed in diabetic conditions. In conclusion, our study highlights the antioxidant, pro-regenerative, anti-lipid accumulation and pro-neurogenic effects of H. lanceolatum in vivo and supports the use of this traditional medicinal plant as a potential alternative in the prevention and/or treatment of metabolic disorders.

Polyphenols: Potential anti-inflammatory agents for treatment of metabolic disorders

Ample evidence highlights the potential benefits of polyphenols in health status especially in obesity-related metabolic disorders such as insulin resistance, type 2 diabetes, and cardiovascular diseases. Mechanistically, due to the key role of "Metainflammation" in the pathomechanism of metabolic disorders, recently much focus has been placed on the properties of polyphenols in obesity-related morbidities. This narrative review summarizes the current knowledge on the role of polyphenols, including genistein, chlorogenic acid, ellagic acid, caffeic acid, and silymarin in inflammatory responses pertinent to metabolic disorders and discusses the implications of this evidence for future directions. This review provides evidence that the aforementioned polyphenols benefit health status in metabolic disorders via direct and indirect regulation of a variety of target proteins involved in inflammatory signaling pathways. However, due to limitations of the in vitro and in vivo studies and also the lack of long-term human clinical trials studies, further high-quality investigations are required to firmly establish the clinical efficacy of the polyphenols for the prevention and management of metabolic disorders.

Acute and sub-chronic toxicity evaluation of a standardized green coffee bean extract (CGA-7™) in Wistar albino rats

OBJECTIVE

Despite having numerous physiological benefits, toxicological assessment of green coffee beans is sparce. Here, we document the oral acute and sub-chronic toxicity of a standardized decaffeinated green coffee bean extract containing 50% chlorogenic acids (CGA-7™) in rats.

METHODS

We have performed a limit test at single oral dose of 2000 mg/kg to evaluate the acute toxicity in female Wistar rats. Furthermore, repeated dose 90-day toxicity study was conducted to assess the risk of long-term use of CGA-7.

RESULT

A 14-day observation revealed no clinical signs of toxicity or mortality in animals at 2000 mg/kg acute oral dose of CGA-7. The administration of 250, 500, and 1000 mg/kg CGA-7 showed significant alterations in some parameters such as food consumption, relative organ weights of brain and spleen, haematological and biochemical parameters compared to control. These changes were not consistent and dose-dependent throughout the study. Furthermore, the changes were within the physiological range and toxicologically insignificant. CGA-7 did not affect the normal metabolism and physiology of the animals up to 1000 mg/kg dose. Macroscopic and histological examination of organs did not reveal any organ toxicity.

CONCLUSION

Finally, the findings from this study suggest the safety of green coffee bean extract.

Pharmacologic Overview of Chlorogenic Acid and its Metabolites in Chronic Pain and Inflammation

BACKGROUND

Natural phenolic compounds in medicinal herbs and dietary plants are antioxidants which play therapeutic or preventive roles in different pathological situations, such as oxidative stress and inflammation. One of the most studied phenolic compounds in the last decade is chlorogenic acid (CGA), which is a potent antioxidant found in certain foods and drinks.

OBJECTIVE

This review focuses on the anti-inflammatory and antinociceptive bioactivities of CGA, and the putative mechanisms of action are described. Ethnopharmacological reports related to these bioactivities are also reviewed.

MATERIALS AND METHODS

An electronic literature search was conducted by authors up to October 2019. Original articles were selected.

RESULTS

CGA has been shown to reduce inflammation and modulate inflammatory and neuropathic pain in animal models.

CONCLUSION

The consensus of the literature search was that systemic CGA may facilitate pain management via bolstering antioxidant defenses against inflammatory insults.

Chlorogenic Acids in Cardiovascular Disease: A Review of Dietary Consumption, Pharmacology, and Pharmacokinetics

Chlorogenic acids (CGAs) have gained considerable attention as pervasive human dietary constituents with potential cardiovascular-preserving effects. The main sources include coffee, yerba mate, Eucommia ulmodies leaves, and Lonicerae Japonicae Flos. CGA consumption can reduce the risks of hypertension, atherosclerosis, heart failure, myocardial infarction, and other factors associated with cardiovascular risk, such as obesity and type 2 diabetes. This review recapitulates recent advances of CGAs in the cardiovascular-preserving effects, pharmacokinetics, sources, and safety. Emerging evidence indicates that CGAs exhibit circulatory guarding properties through the suppression of oxidative stress, leukocyte infiltration, platelet aggregation, platelet-leukocyte interactions, vascular remodeling, and apoptosis as well as the regulation of glucose and lipid metabolism and vasodilatory action in the cardiovascular system. CGAs exert these effects by acting on complex signaling networks, but the global mechanisms are still not clear. The oral bioavailability of CGA is poor, and there is a potential sensitization concern about CGA. The bioactive metabolites, systematic toxicity, and optimized structure are needed for further identification.

A new method of ultra-performance liquid chromatography/tandem mass spectrometry for determination of chlorogenic acid in human plasma and urine

RATIONALE

Chlorogenic acid (CA) is well known for its various biological activities. Here, a clinical study was performed in patients with advanced malignant cancer to explore its therapeutic effects. We aimed to develop a method to quantify CA in human plasma and urine to assist the clinical pharmacokinetic study.

METHODS

Ultra-performance liquid chromatography (UPLC) coupled with a triple quadruple mass spectrometry was used to separate and detect CA, with puerarin serving as the internal standard.

RESULTS

The method presents an excellent linearity ranging from 5 to 2000 ng/mL for plasma analysis and 50 to 20 000 ng/mL for urine analysis. Intra- and inter-day precision and accuracy were both less than 15% for plasma and urine.

CONCLUSIONS

These results showed that the novel UPLC method was robust and sensitive, and fulfilled the requirements for a clinical pharmacokinetic study of CA in patients with advanced cancer.

Increased ROS Scavenging and Antioxidant Efficiency of Chlorogenic Acid Compound Delivered via a Chitosan Nanoparticulate System for Efficient In Vitro Visualization and Accumulation in Human Renal Adenocarcinoma Cells

Naturally existing Chlorogenic acid (CGA) is an antioxidant-rich compound reported to act a chemopreventive agent by scavenging free radicals and suppressing cancer-causing mechanisms. Conversely, the compound’s poor thermal and pH (neutral and basic) stability, poor solubility, and low cellular permeability have been a huge hindrance for it to exhibit its efficacy as a nutraceutical compound. Supposedly, encapsulation of CGA in chitosan nanoparticles (CNP), nano-sized colloidal delivery vector, could possibly assist in enhancing its antioxidant properties, in vitro cellular accumulation, and increase chemopreventive efficacy at a lower concentration. Hence, in this study, a stable, monodispersed, non-toxic CNP synthesized via ionic gelation method at an optimum parameter (600 µL of 0.5 mg/mL of chitosan and 200 µL of 0.7 mg/mL of tripolyphosphate), denoted as CNP°, was used to encapsulate CGA. Sequence of physicochemical analyses and morphological studies were performed to discern the successful formation of the CNP°-CGA hybrid. Antioxidant property (studied via DPPH (1,1-diphenyl-2-picrylhydrazyl) assay), in vitro antiproliferative activity of CNP°-CGA, and in vitro accumulation of fluorescently labeled (FITC) CNP°-CGA in cancer cells were evaluated. Findings revealed that successful formation of CNP°-CGA hybrid was reveled through an increase in particle size 134.44 ± 18.29 nm (polydispersity index (PDI) 0.29 ± 0.03) as compared to empty CNP°, 80.89 ± 5.16 nm (PDI 0.26 ± 0.01) with a maximal of 12.04 μM CGA loaded per unit weight of CNP° using 20 µM of CGA. This result correlated with Fourier-Transform Infrared (FTIR) spectroscopic analysis, transmission Electron Microscopy (TEM) and field emission scanning (FESEM) electron microscopy, and ImageJ evaluation. The scavenging activity of CNP°-CGA (IC₅₀ 5.2 ± 0.10 µM) were conserved and slightly higher than CNP° (IC₅₀ 6.4±0.78 µM). An enhanced cellular accumulation of fluorescently labeled CNP°-CGA in the human renal cancer cells (786-O) as early as 30 min and increased time-dependently were observed through fluorescent microscopic visualization and flow cytometric assessment. A significant concentration-dependent antiproliferation activity of encapsulated CGA was achieved at IC₅₀ of 16.20 µM as compared to CGA itself (unable to determine from the cell proliferative assay), implying that the competent delivery vector, chitosan nanoparticle, is able to enhance the intracellular accumulation, antiproliferative activity, and antioxidant properties of CGA at lower concentration as compared to CGA alone.

Chlorogenic Acid Functions as a Novel Agonist of PPARγ2 during the Differentiation of Mouse 3T3-L1 Preadipocytes

Rosiglitazone (RG) is a well-known activator of peroxisome proliferator-activated receptor-gamma (PPARγ) and used to treat hyperglycemia and type 2 diabetes; however, its clinical application has been confounded by adverse side effects. Here, we assessed the roles of chlorogenic acid (CGA), a phenolic secondary metabolite found in many fruits and vegetables, on the differentiation and lipolysis of mouse 3T3-L1 preadipocytes. The results showed that CGA promoted differentiation in vitro according to oil red O staining and quantitative polymerase chain reaction assays. As a potential molecular mechanism, CGA downregulated mRNA levels of the adipocyte differentiation-inhibitor gene Pref1 and upregulated those of major adipogenic transcriptional factors (Cebpb and Srebp1). Additionally, CGA upregulated the expression of the differentiation-related transcriptional factor PPARγ2 at both the mRNA and protein levels. However, following CGA intervention, the accumulation of intracellular triacylglycerides following preadipocyte differentiation was significantly lower than that in the RG group. Consistent with this, our data indicated that CGA treatment significantly upregulated the expression of lipogenic pathway-related genes Plin and Srebp1 during the differentiation stage, although the influence of CGA was weaker than that of RG. Notably, CGA upregulated the expression of the lipolysis-related gene Hsl, whereas it did not increase the expression of the lipid synthesis-related gene Dgat1. These results demonstrated that CGA might function as a potential PPARγ agonist similar to RG; however, the impact of CGA on lipolysis in 3T3-L1 preadipocytes differed from that of RG.

Sphingosine Kinase-1 Involves the Inhibitory Action of HIF-1α by Chlorogenic Acid in Hypoxic DU145 Cells

Hypoxia enhances cancer development in a solid tumor. Hypoxia-inducible factor-1 α (HIF-1α) is a transcription factor that is dominantly expressed under hypoxia in solid tumor cells and is a key factor that regulates tumor. HIF-1α regulates several target genes involved in many aspects of cancer progression, including angiogenesis, metastasis, anti-apoptosis and cell proliferation as well as imparts resistance to cancer treatment. In this study, we assessed Crataegus Pinnatifida Bunge var. typical Schneider ethanol extract (CPE) for its anti-cancer effects in hypoxia-induced DU145 human prostate cancer cell line. CPE decreased the abundance of HIF-1α and sphingosine kinase-1 (SPHK-1) in hypoxia-induced prostate cancer DU145 cells. CPE decreased HIF-1α and SPHK-1 as well as SPHK-1 activity. Chlorogenic acid (CA) is one of four major compounds of CPE. Compared to CPE, CA significantly decreased the expression of HIF-1α and SPHK-1 as well as SPHK-1 activity in hypoxia-induced DU145 cells. Furthermore, CA decreased phosphorylation AKT and GSK-3β, which are associated with HIF-1α stabilization and affected SPHK-1 in a concentration-dependent manner. We confirmed the mechanism of CA-induced inhibition of HIF-1α by SPHK-1 signaling pathway using SPHK-1 siRNA and SPHK inhibitor (SKI). CA decreased the secretion and cellular expression of VEGF, thus inhibiting hypoxia-induced angiogenesis. Treatment of DU145cells with SPHK1 siRNA and CA for 48 h decreased cancer cell growth, and the inhibitory action of SPHK siRNA and CA on cell growth was confirmed by decrease in the abundance of Proliferating cell nuclear antigen (PCNA).

High sensitivity chlorogenic acid detection based on multiple layer-by-layer self-assembly films of chitosan and multi-walled carbon nanotubes on a glassy carbon electrode

A chlorogenic acid sensor based on a chitosan (CS) and multi-walled carbon nanotubes (MWCNTs) modified glassy carbon electrode (GCE) was fabricated via a layer-by-layer (LBL) self-assembly method.

Graphene oxide as a nanocarrier for controlled release and targeted delivery of an anticancer active agent, chlorogenic acid

We have synthesized graphene oxide using improved Hummer's method in order to explore the potential use of the resulting graphene oxide as a nanocarrier for an active anticancer agent, chlorogenic acid (CA). The synthesized graphene oxide and chlorogenic acid-graphene oxide nanocomposite (CAGO) were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetry and differential thermogravimetry analysis, Raman spectroscopy, powder X-ray diffraction (PXRD), UV-vis spectroscopy and high resolution transmission electron microscopy (HRTEM) techniques. The successful conjugation of chlorogenic acid onto graphene oxide through hydrogen bonding and π-π interaction was confirmed by Raman spectroscopy, FTIR analysis and X-ray diffraction patterns. The loading of CA in the nanohybrid was estimated to be around 13.1% by UV-vis spectroscopy. The release profiles showed favourable, sustained and pH-dependent release of CA from CAGO nanocomposite and conformed well to the pseudo-second order kinetic model. Furthermore, the designed anticancer nanohybrid was thermally more stable than its counterpart. The in vitro cytotoxicity results revealed insignificant toxicity effect towards normal cell line, with a viability of >80% even at higher concentration of 50μg/mL. Contrarily, CAGO nanocomposite revealed enhanced toxic effect towards evaluated cancer cell lines (HepG2 human liver hepatocellular carcinoma cell line, A549 human lung adenocarcinoma epithelial cell line, and HeLa human cervical cancer cell line) compared to its free form.

Chlorogenic Acid Combined with Lactobacillus plantarum 2142 Reduced LPS-Induced Intestinal Inflammation and Oxidative Stress in IPEC-J2 Cells

This study was carried out to investigate protective effect of chlorogenic acid against lipopolysaccharide-induced inflammation and oxidative stress in intestinal epithelial cells. As a marker of inflammatory response, IL-6, IL-8, TNF-α mRNA and protein levels, furthermore, COX-2 mRNA level were followed up. Intracellular redox status and extracellular H2O2 level were also monitored by two fluorescent assays (DCFH-DA, Amplex Red). Moreover, the effect of gut microbiota metabolites in the above mentioned processes was taken into account in our model using Lactobacillus plantarum 2142 bacterial strain. Our data revealed that chlorogenic acid had significant lowering effect on the inflammatory response. Treatment with chlorogenic acid (25-50 μM) significantly decreased gene expression and concentration of proinflammatory cytokines IL-6 and IL-8 compared to LPS-treated cells. COX-2 and TNF-α mRNA levels were also reduced. Furthermore, chlorogenic acid reduced the level of reactive oxygen species in IPEC-J2 cells. Simultaneous application of chlorogenic acid and Lactobacillus plantarum 2142 supernatant resulted protective effect against LPS-induced inflammation and oxidative stress as well.

The Janus face of chlorogenic acid on vascular reactivity: A study on rat isolated vessels

BACKGROUND

Chlorogenic acid (CGA), the main polyphenol contained in coffee, is a major contributor to dietary polyphenol intake. Few studies reported its anti-hypertensive properties but the mechanisms are still indefinite.

PURPOSE

The present study assessed the direct effect of CGA in endothelium denuded or intact aortic rings from male Wistar rats and the mechanisms involved.

METHODS/RESULTS

CGA induced a direct endothelium-dependent relaxation that was significantly reduced by L-NAME (10(-4)M), indomethacin (10(-5)M) and combination of apamin (10(-7)M) and charybdotoxin (10(-7)M). Incubation of rings with CGA induced a dual effect on agonist-induced vasorelaxation. At 10(-6)M, it enhanced the relaxant effects of acetylcholine and reduced the contracting effects of phenylephrine due to increased basal and stimulated NOS activity, respectively. At 10(-4)M, CGA blunted acetylcholine and bradykinin-induced vasorelaxation, reduced phenylephrine-induced vasoconstriction but did not change the response to sodium nitroprusside, a NO-donor.

CONCLUSION

In summary, CGA induces a direct endothelium-dependent vasodilation by increasing NOS, COX and EDHF signalling pathways. However, this new pharmacological action that can explain some positive effects of CGA in case of hypertension has to be modulated at the light of its deleterious impact on vascular relaxation at high concentrations and incite to be cautious when using high doses of CGA in clinical studies.

Chemical Constituents and LC-profile of Fresh Formosan Lonicera Japonica Flower Buds

One new secoiridoid glucoside, ethylsecologanin dimethyl acetal (1), along with 15 known compounds, comprising six iridoid glucosides (2–7), six flavonoids (8–13), two sterol glucosides (14 and 15), and chlorogenic acid (16) were isolated from the flower buds of Formosan Lonicera japonica. The structures of these isolates were determined on the basis of mass and spectroscopic analyzes. In addition, the chemical profiles of fresh Formosan honeysuckle buds and the dried Chinese one were compared by HPLC with a PDA detector. The calibration curve of the active component, chlorogenic acid, was also provided. As a result of the constituent similarity, Formosan L. japonica can be an alternative to the Chinese honeysuckles.

Role of Chlorogenic Acids in Controlling Oxidative and Inflammatory Stress Conditions

Chlorogenic acids (CGAs) are esters formed between caffeic and quinic acids, and represent an abundant group of plant polyphenols present in the human diet. CGAs have different subgroups that include caffeoylquinic, p-coumaroylquinic, and feruloyquinic acids. Results of epidemiological studies suggest that the consumption of beverages such as coffee, tea, wine, different herbal infusions, and also some fruit juices are linked to reduced risks of developing different chronic diseases. These beverages contain CGAs present in different concentrations and isomeric mixtures. The underlying mechanism(s) for specific health benefits attributed to CGAs involves mitigating oxidative stress, and hence the related adverse effects associated with an unbalanced intracellular redox state. There is also evidence to show that CGAs exhibit anti-inflammatory activities by modulating a number of important metabolic pathways. This review will focus on three specific aspects of the relevance of CGAs in coffee beverages; namely: (1) the relative composition of different CGA isomers present in coffee beverages; (2) analysis of in vitro and in vivo evidence that CGAs and individual isomers can mitigate oxidative and inflammatory stresses; and (3) description of the molecular mechanisms that have a key role in the cell signaling activity that underlines important functions.

Effect of 5-caffeoylquinic acid on the NF-κB signaling pathway, peroxisome proliferator-activated receptor gamma 2, and macrophage infiltration in high-fat diet-fed Sprague-Dawley rat adipose tissue

Obesity, considered as a consequence of overnutrition, sustains a low-degree inflammatory state and results in insulin-resistance and type 2 diabetes. Here, we investigated the anti-inflammatory effects of 5-caffeoylquinic acid (5-CQA) in high-fat diet-induced obese rats. Serum interleukin (IL)-6, monocyte chemotactic protein 1 (MCP-1), tumor necrosis factor-alpha (TNF-α), total cholesterol (TC), triglyceride (TG), and free fatty acid (FFA) levels were determined. Expression of genes related to TG metabolism, macrophage biomarkers, and inflammation was assessed by real-time PCR. Protein expression of NF-κB, PPARγ2, and phosphorylated IκBα was evaluated by western blotting, and the histology of adipose tissue was examined. Supplementation of the rat diet with 5-CQA reduced obesity development, macrophage infiltration, and steatosis. Additionally, 5-CQA decreased the expression of NF-κB and downstream inflammatory cytokines, but increased the expression of PPARγ2, in a dose-dependent manner. Thus, 5-CQA improved obesity and obesity-related metabolic disturbances via PPARγ2 and the NF-κB signaling pathway.

5-Caffeoylquinic acid decreases diet-induced obesity in rats by modulating PPARα and LXRα transcription

BACKGROUND

Chlorogenic acids (CGAs) are widely distributed in plant material, including foods and beverages. 5-Caffeoylquinic acid (5-CQA) is the most studied CGA, but the mechanism of its hypolipidaemic effect remains unclear. This study aimed to determine the effect of 5-CQA on lipid metabolism in the liver of Sprague-Dawley rats fed a high-fat diet (HFD).

RESULTS

5-CQA suppressed HFD-induced increases in body weight and visceral fat-pad weight, serum lipid levels, and serum and hepatic free fatty acids in a dose-dependent manner. Real-time polymerase chain reaction revealed that 5-CQA altered the mRNA expression of the transcription factors peroxisome proliferator-activated receptor α (PPARα) and liver X receptor α (LXRα) and target genes involved in hepatic fatty acid uptake, β-oxidation, fatty acid synthesis, and cholesterol synthesis. Moreover, hepatic tissue sections from HFD-fed rats showed many empty vacuoles, suggesting that liver cells were filled with more fat droplets. However, 5-CQA significantly ameliorated this effect.

CONCLUSION

5-CQA may improve lipid metabolism disorders by altering the expression of PPARα and LXRα, which are involved in multiple intracellular signalling pathways.

Anti-inflammatory, antioxidant and anti-acetylcholinesterase activities of Bouvardia ternifolia: potential implications in Alzheimer's disease

Bouvardia ternifolia has been used medicinally to treat inflammation. In the present study, we investigate the anti-Alzheimer's potential effect of the hydroalcoholic extract of B. ternifolia through evaluation of anti-inflammatory and antioxidant activities, quantification of the percentage inhibition of acetylcholinesterase activity, protection effect against β-amyloid fibrillar-induce neurotoxicity, and the identification of the main constituents. Our results show that B. ternifolia extract and ethyl acetate fraction induced anti-inflammatory effects by reducing inflammation by >70 %, while antioxidant test revealed significant IC50 values for flavonoid content fraction (30.67 ± 2.09 μg/ml) and ethyl acetate fraction (42.66 ± 0.93 μg/ml). The maximum inhibition of acetylcholinesterase was exhibited by scopoletin content fraction (38.43 ± 3.94 %), while ethyl acetate fraction exerted neuroprotective effect against β-amyloid peptide (83.97 ± 5.03 %). Phytochemical analysis, showed the presence of 3-O-quercetin glucopyranoside (415 mg/g), rutin (229.9 mg/g), ursolic and oleanolic acid (54 and 20.8 mg/g respectively), 3-O-quercetin rhamnopyranoside (12.8 mg/g), chlorogenic acid (9.5 mg/g), and scopoletin (1.38 mg/g). Our findings support the use of B. ternifolia since the extract induced significant neuroprotection against β-amyloid peptide, anti-inflammatory, antioxidant and anti-acetylcholinesterase effects that could be attributed to its contents of polyphenols, coumarins, and triterpenes, and encourage further studies for development of this extract as therapeutic agent in treatment of Alzheimer's disease.

Chlorogenic acid inhibits hypoxia-induced angiogenesis via down-regulation of the HIF-1α/AKT pathway

BACKGROUND

The hypoxia-inducible factor-1 (HIF-1) is known to play an important role in cellular responses to hypoxia, including the transcriptional activation of a number of genes involved in tumor angiogenesis. Chlorogenic acid (CGA), one of the most abundant polyphenols in the human diet, has been reported to inhibit cancer cell growth. The effect of CGA on tumor angiogenesis and its underlying mechanisms are, as yet, unknown.

METHODS

The effect of CGA on HIF-1α expression was assessed by Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR) assays in A549 lung cancer cells. The transcriptional activity of the HIF-1 complex was confirmed using a luciferase assay. To assess whether angiogenic factors are increased under hypoxic conditions in these cells, vascular endothelial growth factor (VEGF) expression levels were measured by RT-PCR and Western blotting. The direct effect of CGA on human vascular endothelial cells (HUVEC) under hypoxic conditions was analyzed using in vitro assays, including tube-formation, wound healing and Transwell invasion assays. To investigate the effect of CGA on angiogenesis in vivo, we performed a Matrigel plug assay in a mouse model. Finally, the effect of CGA on AKT and ERK activation (phosphorylation) as a putative mechanism underlying the effect of CGA on VEGF-mediated angiogenesis inhibition was assessed using Western blotting.

RESULTS

We found that CGA significantly decreases the hypoxia-induced HIF-1α protein level in A549 cells, without changing its mRNA level. CGA was, however, found to suppress the transcriptional activity of HIF-1α under hypoxic conditions, leading to a decrease in the expression of its downstream target VEGF. We also found that CGA can block hypoxia-stimulated angiogenesis in vitro and VEGF-stimulated angiogenesis in vivo using HUVEC cells. In addition, we found that CGA can inhibit the HIF-1α/AKT signaling pathway, which plays an important role in VEGF activation and angiogenesis.

CONCLUSIONS

Our data indicate that CGA plays a role in the suppression of angiogenesis via inhibition of the HIF-1α/AKT pathway. CGA may represent a novel therapeutic option for the treatment of (lung) cancer.