Improvement of hypertension and vascular dysfunction by hydroxyhydroquinone-free coffee in a genetic model of hypertension

Protein-Chlorogenic Acid Interactions: Mechanisms, Characteristics, and Potential Food Applications

The interactions between proteins and chlorogenic acid (CGA) have gained significant attention in recent years, not only as a promising approach to modify the structural and techno-functional properties of proteins but also to enhance their bioactive potential in food systems. These interactions can be divided into covalent (chemical or irreversible) and non-covalent (physical or reversible) linkages. Mechanistically, CGA forms covalent bonds with nucleophilic amino acid residues of proteins by alkaline, free radical, and enzymatic approaches, leading to changes in protein structure and functionality, such as solubility, emulsification properties, and antioxidant activity. In addition, the protein-CGA complexes can be obtained by hydrogen bonds, hydrophobic and electrostatic interactions, and van der Waals forces, each offering unique advantages and outcomes. This review highlights the mechanism of these interactions and their importance in modifying the structural, functional, nutritional, and physiological attributes of animal- and plant-based proteins. Moreover, the potential applications of these protein-CGA conjugates/complexes are explored in various food systems, such as beverages, films and coatings, emulsion-based delivery systems, and so on. Overall, this literature review provides an in-depth overview of protein-CGA interactions, offering valuable insights for future research to develop novel protein-based food and non-food products with improved nutritional and functional characteristics.

DNA Mutagenicity of Hydroxyhydroquinone in Roasted Coffee Products and Its Suppression by Chlorogenic Acid, a Coffee Polyphenol, in Oxidative-Damage-Sensitive SAMP8 Mice

Hydroxyhydroquinone (HHQ) is an oxidative component produced by roasting coffee beans and has been reported to generate relatively large amounts of reactive oxygen species (ROS). In this study, we used senescence-accelerated mouse prone 8 (SAMP8) mice to determine whether HHQ consumption increases oxidative-stress-induced injury, because in SAMP8 mice, the activity of 8-oxoguanine DNA glycosylase 1, which repairs oxidative modifications in DNA, is decreased. The results showed that two out of twelve (16.7%) HHQ-treated mice presented polyuria and glucosuria around 2 months after the start of treatment, indicating that HHQ may act as a mutagen against SAMP8 mice, which is sensitive to oxidative damage. No abnormalities were observed in the chlorogenic acid (coffee polyphenol, CPP)-treated group. The concentration of hydrogen peroxide in the serum of SAMP8 mice was significantly higher than that in SAMR1 (senescence-resistant) control mice, and the concentration was further increased in the HHQ-treated group. CPP, when coexisting with HHQ at the rate contained in roasted coffee, decreased the amount of hydrogen peroxide in the serum of SAMP8 mice. Although CPP can act both oxidatively and antioxidatively as a polyphenol, CPP acts more antioxidatively when coexisting with HHQ. Thus, the oxidative effect of HHQ was shown to be counteracted by CPP.

A Study on the Safety and Effects of Amorpha fruticosa Fruit Extract on Spontaneously Hypertensive Rats with Induced Type 2 Diabetes

Metabolic syndrome is characterized by a variety of diagnostic criteria: obesity, dyslipidemia, type 2 diabetes, and arterial hypertension. They contribute to the elevated risk of cardiovascular morbidity and mortality. The potential for Amorpha fruticosa L. (Fabaceae) to improve diabetes and metabolic disease is promising, based on in vitro tests. This is why a further investigation of the species is needed. Additionally, a toxicity review in relation to safety revealed that to date, there are no published data regarding the toxicity of A. fruticosa towards humans. This species could provide abundant and cheap resources because it is an aggressive invasive plant that grows almost unrestrictedly. The objective of this study was to evaluate the acute toxicity of a purified extract of A. fruticosa (EAF), and to assess its antioxidant, antihypertensive, and antihyperglycemic activity in streptozotocin-induced diabetic spontaneously hypertensive rats (SHRs). The EAF was slightly toxic (LD50 = 2121 mg/kg, b.w.) when administered orally, and moderately toxic (LD50 = 316 mg/kg, b.w.) at intraperitoneal administration, both in mice. The oral administration of EAF (100 mg/kg) for 35 days to SHRs caused significant decreases in the systolic pressure, blood glucose levels, and MDA quantity. It also increased the hepatic level of the endogenous antioxidant GSH, not only in diabetic SHRs, but also in the control group. An additional potential benefit to human health might be conferred through the environmental management of A. fruticosa based on its large-scale use for medicinal purposes, as this aggressive invasive species brings problems to natural habitats in many European countries.

Recovery from Food Waste-Biscuit Doughs Enriched with Pomegranate Peel Powder as a Model of Fortified Aliment

The aim of the present work is the characterization of biscuit doughs enriched with pomegranate peel powder (PPP) at 3 (PPP3) and 5 (PPP5) wt% in the prospect of developing a fortified aliment as a support of the therapy of chronic inflammatory diseases of the intestinal tract. The total phenolic content of the powder was preliminarily evaluated. Then, the main compounds present in the PPP were identified by HPLC-ESI-TOF-MS analysis, being mainly hydrolysable tannins. The PPP was then treated at 180 °C for 20 min to mimic the baking treatment, and its water-soluble fraction (PPPwsf) was then added in the Caco-2 cell culture as a model of the intestinal epithelial barrier to verify its dose-dependent toxicity, ability in counteracting the oxidative stress, and anti-inflammatory action. Rheological experiments were performed to predict the macroscopic behavior of the PPP-added doughs during lamination and biscuit baking. SEM investigations gave their contribution to the microscopic comprehension of the dough structure. Finally, a consumer panel composed by thirty volunteers was enrolled to express its opinion on the sensory agreeableness of the biscuits prepared with two different concentrations of PPP compared with the reference dough. The discussion is focused on the biological effects of the main components found in the PPP.

Effects of Chlorogenic Acids on Menopausal Symptoms in Healthy Women: A Randomized, Placebo-Controlled, Double-Blind, Parallel-Group Trial

A reduction in estrogen levels in the perimenopausal and postmenopausal periods causes various symptoms in women, such as hot flushes, sweats, depression, anxiety, and insomnia. Chlorogenic acids (CGAs), which are phenolic compounds widely present in plants such as coffee beans, have various physiological functions. However, the effects of CGAs on menopausal symptoms are unknown. To examine the effects of CGAs on menopausal symptoms, especially hot flushes, a randomized, placebo-controlled, double-blind, parallel-group trial was conducted in healthy women. Eighty-two subjects were randomized and assigned to receive CGAs (270 mg) tablets or the placebo for 4 weeks. After 4 weeks of intake, the number of hot flushes, the severity of hot flushes during sleep, and the severity of daytime sweats decreased significantly in the CGA group compared to the placebo group. The modified Kupperman index for menopausal symptoms decreased significantly after 2 weeks in the CGA group compared to the placebo group. Adverse effects caused by CGAs were not observed. The results show that continuous intake of CGAs resulted in improvements in menopausal symptoms, especially hot flushes, in healthy women.

The sources and mechanisms of bioactive ingredients in coffee

Coffee bioactive components include caffeine, chlorogenic acids (CGAs), trigonelline, tryptophan alkaloids, diterpenes and other secondary metabolites. During roasting, coffee metabolites undergo complex Maillard reactions, producing melanoidins and other degradation products, the most controversial among which is acrylamide, an ingredient widely found in baked food and listed as a second class carcinogen. Green and roasted coffee ingredients have good biological activities for the prevention of cardiovascular disease, and antibacterial, anti-diabetic, neuroprotection, and anti-cancer activities. To better understand the relationship between coffee ingredients and human health, and to effectively use the active ingredients, it is essential to understand the sources of coffee active ingredients and their mechanisms of action in the organism. This paper systematizes the available information and provides a critical overview of the sources of coffee active ingredients and the mechanisms of action in vivo or in vitro, and their combined effects on common human diseases.

Effects of Chlorogenic Acid-Enriched and Hydroxyhydroquinone-Reduced Coffee on Postprandial Fat Oxidation and Antioxidative Capacity in Healthy Men: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial

Chlorogenic acids (CGAs) reduce blood pressure and body fat, and enhance fat metabolism. In roasted coffee, CGAs exist together with the oxidant component hydroxyhydroquinone (HHQ). HHQ counteracts the antihypertensive effects of CGA, but its effects on CGA-induced fat oxidation (FOX) are unknown. Here we assessed the effects of CGA-enriched and HHQ-reduced coffee on FOX. Fifteen healthy male volunteers (age: 38 ± 8 years (mean ± SD); BMI: 22.4 ± 1.5 kg/m²) participated in this crossover study. Subjects consumed the test beverage (coffee) containing the same amount of CGA with HHQ (CGA-HHQ(+)) or without HHQ (CGA-HHQ(−)) for four weeks. Postprandial FOX and the ratio of the biological antioxidant potential (BAP) to the derivatives of reactive oxygen metabolites (d-ROMs) as an indicator of oxidative stress were assessed. After the four-week intervention, postprandial FOX and the postprandial BAP/d-ROMs ratio were significantly higher in the CGA-HHQ(−) group compared with the CGA-HHQ(+) group (4 ± 23 mg/min, group effect: p = 0.040; 0.27 ± 0.74, group effect: p = 0.007, respectively). In conclusion, reducing the amount of HHQ facilitated the postprandial FOX effects of CGA in coffee. Our findings also suggest that the mechanism underlying the inhibition of FOX by HHQ is related to postprandial oxidative stress.

Hydroxyhydroquinone impairs fat utilization in mice by reducing nitric oxide availability

Habitual consumption of chlorogenic acid compounds (CGAs) from coffee increases fat catabolism and reduces body fat; however, the contribution of roasted coffee remains unclear. Hydroxyhydroquinone (HHQ) impairs the vasodilatory and antihypertensive effects of CGAs by reducing nitric oxide (NO) bioavailability. Since HHQ also reduces fat catabolism, we hypothesized that HHQ does so by decreasing NO availability. Therefore, we investigated the effect of HHQ on energy metabolism in KKAy mice. In HHQ-treated mice, fat oxidation was significantly low and dose-dependent, serum and urinary hydrogen peroxide were high, and plasma NO metabolites and S-nitrosylated liver proteins were low. In HHQ-treated mouse hepatocytes, the palmitate-induced increase in cellular oxygen consumption was negatively affected, and HHQ or L-NAME reduced cellular fatty acid utilization. In conclusion, HHQ can impair fat utilization by reducing NO availability in mice. Protein S-nitrosylation reduction in liver cells after HHQ consumption may be associated with impaired fatty acid oxidation.

Coffee consumption and risk of hypertension: a dose-response meta-analysis of prospective studies

PURPOSE

Recently, a large prospective study provided additional information concerning the debated possible association between habitual coffee consumption and risk of hypertension (HPT). Therefore, we updated the state of knowledge on this issue by carrying out a comprehensive new systematic review of the literature and a meta-analysis of the available relevant studies.

METHODS

We performed a systematic search for prospective studies on general population, published without language restrictions (1966-August 2017). A random-effects dose-response meta-analysis was conducted to combine study specific relative risks (RRs) and 95% confidence intervals. Potential non-linear relation was investigated using restricted cubic splines.

RESULTS

Four studies (196,256 participants, 41,184 diagnosis of HPT) met the inclusion criteria. Coffee intake was assessed by dietary questionnaire. Dose-response meta-analysis showed a non-linear relationship between coffee consumption and risk of HPT (p for non-linearity < 0.001). Whereas the habitual drinking of one or two cups of coffee per day, compared with non-drinking, was not associated with risk of HPT, a significantly protective effect of coffee consumption was found starting from the consumption of three cups of coffee per day (RR = 0.97, 95% CI = 0.94 to 0.99), and was confirmed for greater consumption.

CONCLUSIONS

The results of this analysis indicate that habitual moderate coffee intake is not associated with higher risk of HPT in the general population and that in fact a non-linear inverse dose-response relationship occurs between coffee consumption and risk of HPT.

Chlorogenic acid from coffee beans: evaluating the evidence for a blood pressure-regulating health claim

The consumption of coffee has been associated with a number of health benefits, including a reduced risk of cardiovascular disease. Hypertension is an important risk factor for adverse cardiovascular events. Coffee may help reduce blood pressure (BP) in humans, which might be attributable to its polyphenolic compound, chlorogenic acid. The high incidence of hypertension among Canadians underscores the need for new and effective strategies to reduce BP. Dietary interventions may constitute such a strategy, but consumers need to be informed about which foods are most effective for regulating BP. To guide healthy eating, Health Canada permits the use of health claims on the labels of foods that confer health benefits. Currently, there is only one health claim for BP regulation. Additional health claims for foods that assist in BP regulation are therefore warranted. This review provides background information on chlorogenic acid and examines the evidence regarding the use of chlorogenic acid for BP regulation in the context of Health Canada's health claims framework.

The potential effects of chlorogenic acid, the main phenolic components in coffee, on health: a comprehensive review of the literature

Chlorogenic acid (CGA), an important biologically active dietary polyphenol, is produced by certain plant species and is a major component of coffee. Reduction in the risk of a variety of diseases following CGA consumption has been mentioned in recent basic and clinical research studies. This systematic review discusses in vivo animal and human studies of the physiological and biochemical effects of chlorogenic acids (CGAs) on biomarkers of chronic disease. We searched PubMed, Embase, Amed and Scopus using the following search terms: ("chlorogenic acid" OR "green coffee bean extract") AND (human OR animal) (last performed on April 1st, 2015) for relevant literature on the in vivo effects of CGAs in animal and human models, including clinical trials on cardiovascular, metabolic, cancerogenic, neurological and other functions. After exclusion of editorials and letters, uncontrolled observations, duplicate and not relevant publications the remaining 94 studies have been reviewed. The biological properties of CGA in addition to its antioxidant and anti-inflammatory effects have recently been reported. It is postulated that CGA is able to exert pivotal roles on glucose and lipid metabolism regulation and on the related disorders, e.g. diabetes, cardiovascular disease (CVD), obesity, cancer, and hepatic steatosis. The wide range of potential health benefits of CGA, including its anti-diabetic, anti-carcinogenic, anti-inflammatory and anti-obesity impacts, may provide a non-pharmacological and non-invasive approach for treatment or prevention of some chronic diseases. In this study, the effects of CGAs on different aspects of health by reviewing the related literatures have been discussed.

Coffee consumption and risk of hypertension in the Polish arm of the HAPIEE cohort study

BACKGROUND/OBJECTIVES

Coffee consumption has been hypothesized to be associated with blood pressure (BP), but previous findings are not homogeneous. The aim of this study was to evaluate the association between coffee consumption and the risk of developing hypertension.

SUBJECTS/METHODS

Data on coffee consumption, BP and use of anti-hypertensive medicament were derived from 2725 participants of the Polish arm of the HAPIEE project (Health, Alcohol and Psychosocial factors In Eastern Europe) who were free of hypertension at baseline and followed up for an average of 5 years. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by multivariate logistic regression analyses and stratified for potential confounding factors.

RESULTS

Coffee consumption was related to decreased age, smoking status and total energy intake. Compared with persons who drink <1 cup coffee per day, systolic BP was significantly associated with coffee consumption and the risk of hypertension was lower for individuals consuming 3-4 cups per day. Despite the analysis stratified by gender showed that the protective effect of coffee consumption on hypertension was significant only in women, the analysis after stratification by smoking status revealed a decreased risk of hypertension in non-smokers drinking 3-4 cups of coffee per day in both sexes (OR 0.41, 95% CI: 0.21, 0.79 for men and OR 0.54, 95% CI: 0.29, 0.99 for women). Upper category coffee consumption (>4 cups per day) was not related to significant increased risk of hypertension.

CONCLUSIONS

Relation between coffee consumption and incidence of hypertension was related to smoking status. Consumption of 3-4 cups of coffee per day decreased the risk of hypertension in non-smoking men and women only.

Mechanisms of the dilator action of the Erigerontis Herba on rat aorta

ETHNOPHARMACOLOGICAL RELEVANCE

Erigerontis Herba is widely used as a traditional Chinese medicine and is commonly used for neuroprotection and vascular protection.

AIM OF STUDY

In this study, the vasodilator effects of Erigerontis Herba (DZXX) were investigated using rat isolated aorta rings.

MATERIAL AND METHOD

The involvement of endothelium in the vasorelaxation was studied by comparing response of endothelium-intact and endothelium-denuded aorta rings which precontracted with U46619. The involvement of K(+) channels was studied by pretreatment of the aorta rings with various K(+) channel inhibitors. The involvement of Ca(2+) channel was studied by incubating aorta rings with Ca(2+)-free solution, primed with U46619 prior to elicit contraction by addition of Ca(2+) solution.

RESULTS

DZXX (0.2-2mg/ml) induced a concentration-dependent relaxation on U44619-precontracted aorta rings with EC50 of 0.354±0.036mg/ml. Removal of endothelium or pretreatment with a BKCa inhibitor iberiotoxin, KIR inhibitor barium chloride or Kv inhibitor 4-aminopyridine produced no effect on the DZXX-induced vasorelaxation. However, pretreatment with a KATP inhibitor glibenclamide or a non-selective K(+) channel inhibitor tetraethylammonium produced significant inhibition on the DZXX-induced vasorelaxation by 29.9% and 21.3%, respectively. Pretreatment with DZXX (0.4, 1.2 and 2mg/ml) produced a concentration-dependent inhibition on Ca(2+)-induced vasoconstriction.

CONCLUSIONS

These results suggest that the vasodilator effect of DZXX was endothelium-independent, mediated by decreasing the influx of Ca(2+) by calcium channel inhibition and increasing the influx of K(+) by opening of a KATP channel.

Current evidence for the use of coffee and caffeine to prevent age-related cognitive decline and Alzheimer's disease

Although nothing has been proven conclusively to protect against cognitive aging, Alzheimer's disease or related dementias, decades of research suggest that specific approaches including the consumption of coffee may be effective. While coffee and caffeine are known to enhance short-term memory and cognition, some limited research also suggests that long-term use may protect against cognitive decline or dementia. In vitro and pre-clinical animal models have identified plausible neuroprotective mechanisms of action of both caffeine and other bioactive components of coffee, though epidemiology has produced mixed results. Some studies suggest a protective association while others report no benefit. To our knowledge, no evidence has been gathered from randomized controlled trials. Although moderate consumption of caffeinated coffee is generally safe for healthy people, it may not be for everyone, since comorbidities and personal genetics influence potential benefits and risks. Future studies could include short-term clinical trials with biomarker outcomes to validate findings from pre-clinical models and improved epidemiological studies that incorporate more standardized methods of data collection and analysis. Given the enormous economic and emotional toll threatened by the current epidemic of Alzheimer's disease and other dementias, it is critically important to validate potential prevention strategies such as coffee and caffeine.

An outlook on chlorogenic acids-occurrence, chemistry, technology, and biological activities

Phenolics are widespread dietary antioxidants. Among these, chlorogenic acids (CGAs) received considerable attention for their wide distribution and part of human diet with potential biological effects. CGAs (71 compounds), being esters of derivatives of cinnamic acids with quinic acid are widely distributed in plant materials. Coffee is among the highest found in plants, ranging from 4 to 14%. Besides, these are reported in plant foods such as apples, pears, carrot, tomato, sweet potato, Phyllostachys edulis, oilseeds, Prunus domestica L, cherries, and eggplant. The traditional Chinese medicinal plants such as flowers and buds of Lonicera japonica Thunb and the leaves of Eucommia ulmodies contained CGAs as bioactive compound. These play an important role in the formation of roasted coffee flavor and have a marked influence on coffee cup quality. CGAs are considered as main precursors of coffee flavor and pigments. Recent technological advancements in the separation and purification of CGAs such as molecular-imprinted polymer technique; microwave-assisted extraction; pH gradient counter current chromatography has also been described. The consumption of coffee correlated to several health benefits such as reducing the risk of human chronic diseases such as inflammation, diabetes, and cardiovascular disease owing to its antioxidant potential.

The effect of coffee consumption on blood pressure and the development of hypertension: a systematic review and meta-analysis

CONTEXT

Coffee is one of the most widely consumed beverages worldwide and is known to acutely raise blood pressure (BP), but the effects of chronic consumption on BP is unclear.

OBJECTIVES

To conduct a systematic review and meta-analysis of available randomized controlled trials (RCTs) and cohort studies to assess the effect of chronic coffee consumption on BP and the development of hypertension.

DATA SOURCES

Ovid, MEDLINE (from 1948), EMBASE (from 1988), and all of Web of Science and Scopus.

STUDY SELECTION

RCTs and cohort studies of at least 1-week duration that assessed BP and/or the incidence of hypertension in coffee consumers compared with a control group that consumed less or no coffee.

DATA EXTRACTION

Two authors independently reviewed abstracts and full-text articles for inclusion. Data were abstracted using standardized forms. Risk of bias in the RCTs was examined using the method described in the Cochrane Handbook for Systematic Reviews of Interventions. Quality of the cohort studies were assessed using the Newcastle-Ottawa quality assessment scale for cohort studies.

DATA SYNTHESIS

Six hundred and ten articles were retrieved and a total of 15 (10 RCTs and five cohort studies) met inclusion criteria. Meta-analysis of RCTs demonstrated a pooled weighted difference in mean change in SBP of -0.55 mmHg [95% confidence interval (CI) -2.46 to 1.36) and DBP -0.45 mmHg (95% CI -1.52 to 0.61). Meta-analysis of the cohort studies demonstrated a pooled risk ratio for developing hypertension of 1.03 (95% CI 0.98-1.08).

CONCLUSION

Low-quality evidence did not show any statistically significant effect of coffee consumption on BP or the risk of hypertension. Given the quality of the currently available evidence, no recommendation can be made for or against coffee consumption as it relates to BP and hypertension.

Purification and identification of antihypertensive peptides from fermented buckwheat sprouts

Buckwheat (Fagopyrum esculentum) is rich in antihypertensive compounds. This study investigated the effect of lactic-fermented buckwheat sprouts (neo-FBS) on level, identification, and potency of blood pressure-lowering (BPL) compounds. A single oral dose of 1.0 mg/kg body weight buckwheat sprouts (BS) in spontaneously hypertensive rats did not show significant BPL activity, whereas neo-FBS significantly decreased blood pressure. HPLC of neo-FBS identified two peaks absent in the profile of BS. The peak exhibiting potent BPL activity was fractionated, and six peptides (DVWY, FDART, FQ, VAE, VVG, and WTFR) and tyrosine were identified by LC-MS/MS and Edman degradation. Single oral dose administration of the peptides revealed significant BPL effect of all the peptides, with the most potent being DVWY, FQ, and VVG. DVWY, VAE, and WTFR are novel. This study demonstrates that lactic fermentation of BS produces new, highly potent antihypertensive peptides and increases active compounds GABA and tyrosine already present in BS.

Consumption of a boiled Greek type of coffee is associated with improved endothelial function: The Ikaria Study

Objective:

The association of coffee consumption with cardiovascular disease remains controversial. Endothelial function is associated with cardiovascular risk. We examined the association between chronic coffee consumption and endothelium function in elderly inhabitants of the island of Ikaria.

Methods:

The analysis was conducted on 142 elderly subjects (aged 66–91 years) of the Ikaria Study. Endothelial function was evaluated by ultrasound measurement of flow-mediated dilation (FMD). Coffee consumption was evaluated based on a food frequency questionnaire and was categorized as ‘low’ (< 200 ml/day), ‘moderate’ (200–450 ml/day), or ‘high’ (> 450 ml/day).

Results:

From the subjects included in the study, 87% consumed a boiled Greek type of coffee. Moreover, 40% had a ‘low’, 48% a ‘moderate’ and 13% a ‘high’ daily coffee consumption. There was a linear increase in FMD according to coffee consumption (‘low’: 4.33 ± 2.51% vs ‘moderate’: 5.39 ± 3.09% vs ‘high’: 6.47 ± 2.72%; p = 0.032). Moreover, subjects consuming mainly a boiled Greek type of coffee had a significantly higher FMD compared with those consuming other types of coffee beverages ( p = 0.035).

Conclusions:

Chronic coffee consumption is associated with improved endothelial function in elderly subjects, providing a new connection between nutrition and vascular health.

Chlorogenic acid ameliorates brain damage and edema by inhibiting matrix metalloproteinase-2 and 9 in a rat model of focal cerebral ischemia

Chlorogenic acid (CGA) has been reported to have various beneficial effects on the cardiovascular and central nervous systems. The purpose of the current study was to investigate whether CGA has protective effects against cerebral ischemia and whether these effects are due to modification of brain edema-related vascular factors. In a rat model of transient middle cerebral artery occlusion (MCAo, 2h of occlusion followed by 22 h of reperfusion), we measured infarct volume and performed behavioral test to evaluate the effects of CGA on brain damage and sensory-motor functional deficits. Brain water content and Evans blue extravasation were measured to evaluate brain edema and blood brain barrier (BBB) damage. Lipid peroxidation (LPO) and the expressions and activities of matrix metalloproteinase (MMP)-2 and MMP-9 were measured to investigate the mechanisms of action. Intraperitoneal injection of CGA (3, 10, and 30 mg/kg) at 0 h and 2h after MCAo dose-dependently reduced infarct volume and sensory-motor functional deficits. It also reduced brain water content and Evans blue extravasation. Mechanistically, CGA reduced LPO and MMPs expressions and activities. These results suggest that CGA reduces brain damage, BBB damage and brain edema by radical scavenging activity and the inhibitory effects on MMP-2 and MMP-9.

Oil palm vegetation liquor: a new source of phenolic bioactives

Waste from agricultural products represents a disposal liability, which needs to be addressed. Palm oil is the most widely traded edible oil globally, and its production generates 85 million tons of aqueous by-products annually. This aqueous stream is rich in phenolic antioxidants, which were investigated for their composition and potential in vitro biological activity. We have identified three isomers of caffeoylshikimic acid as major components of oil palm phenolics (OPP). The 2,2-diphenyl-1-picrylhydrazyl assay confirmed potent free radical scavenging activity. To test for possible cardioprotective effects of OPP, we carried out in vitro LDL oxidation studies as well as ex vivo aortic ring and mesenteric vascular bed relaxation measurements. We found that OPP inhibited the Cu-mediated oxidation of human LDL. OPP also promoted vascular relaxation in both isolated aortic rings and perfused mesenteric vascular beds pre-contracted with noradrenaline. To rule out developmental toxicity, we performed teratological studies on rats up to the third generation and did not find any congenital anomalies. Thus, these initial studies suggest that OPP is safe and may have a protective role against free radical damage, LDL oxidation and its attendant negative effects, as well as vascular constriction in mitigating atherosclerosis. Oil palm vegetation liquor thus represents a new source of phenolic bioactives.

Greater coffee intake in men is associated with steeper age-related increases in blood pressure

BACKGROUND

Administration of caffeine or caffeinated coffee in laboratory and ambulatory settings results in small to moderate acute increases in blood pressure (BP). However, habitual coffee intake has not been linked conclusively to long-term increases in basal BP, and findings are inconsistent by sex. This study examined longitudinal relations of habitual coffee use to resting BP and pulse pressure.

METHODS

In a sample of 2,442 participants from the Baltimore Longitudinal Study of Aging (BLSA), coffee consumption was used to predict resting systolic and diastolic BP and pulse pressure using longitudinal mixed-effects regression models adjusted for age, education, antihypertensive, and antihyperlipidemic use, smoking, and body mass index (BMI). Analyses were stratified by sex (865 women and 1,577 men), and age and BMI were examined as possible effect modifiers.

RESULTS

In men, we identified a significant three-way interaction among coffee intake (nonlinear), baseline age, and length of follow-up for systolic BP (SBP) and pulse pressure. A significant interaction of coffee intake and BMI (nonlinear) was also noted for SBP in men. There were no significant relations of coffee intake to BP or pulse pressure in women.

CONCLUSION

Greater coffee intake in men was associated with steeper age-related increases in SBP and pulse pressure, particularly beyond 70 years of age and in overweight to obese men.

Does dark chocolate have a role in the prevention and management of hypertension?: commentary on the evidence

The notion that eating chocolate would prevent or treat hypertension is appealing to many who produce and enjoy chocolate. Several studies have documented beneficial effects of dark chocolate on insulin action and endothelial function. However, the published studies on chocolate and blood pressure include a relatively small number of subjects, and results are conflicting. In addition, because of secrecy surrounding the production of chocolate and the unique sociocultural context of this popular food, research on efficacy and effectiveness is complex. This commentary summarizes 13 peer-reviewed studies on dark chocolate and blood pressure and raises questions relevant to its future as an evidence-based lifestyle intervention.

Effects of hydroxyhydroquinone-reduced coffee on vasoreactivity and blood pressure

Recent studies suggest that chlorogenic acids, which are the main components of the polyphenol class in coffee, decrease blood pressure, and that hydroxyhydroquinone (HHQ), which is generated by roasting coffee beans, inhibits the antihypertensive effect of chlorogenic acids in brewed coffee. Here, we examined the vasoreactivity and antihypertensive effects of HHQ-reduced coffee in mild hypertension. The study design was a double blind, randomized, placebo-controlled intervention study, with a 4-week run-in period, followed by an 8-week test beverage ingestion period. The subjects were Japanese men and women with mild hypertension and vascular failure, who were not taking any antihypertensive drugs. During the test beverage ingestion period, the subjects ingested either active or placebo HHQ-reduced coffee (chlorogenic acids per 184 ml of coffee: active, 300 mg; and placebo, 0 mg) daily. Subjects were randomly divided into two groups: active group (n=9) and placebo group (n=12). In the active beverage group, endothelium-dependent, flow-mediated vasodilation impairment was significantly ameliorated and systolic blood pressure was significantly decreased from the baseline, but not in the placebo group. There were no test beverage consumption-related changes in other parameters that may influence blood pressure, such as pulse, cardiac output, body weight or 24-h urine volume. Ingestion of the active beverage significantly decreased urinary isoprostane levels, suggesting a reduced oxidative stress. These findings indicate that HHQ-reduced coffee decreased blood pressure in subjects with mild hypertension. The decreased blood pressure was associated with improved vascular endothelial function.

Moderate coffee consumption lowers the likelihood of developing left ventricular systolic dysfunction in post-acute coronary syndrome normotensive patients

The aim of the present work was to evaluate the association between coffee consumption and the development of left ventricular systolic dysfunction (LVSD) in patients who had had an acute coronary syndrome. During 2006-2007, 144 male (65 +/- 14 years) and 50 female (71 +/- 12 years) post-acute coronary syndrome patients who developed LVSD (ejection fraction <40%) after the cardiac event and 129 male (64 +/- 12 years) and 51 female (67 +/- 10 years) post-acute coronary syndrome patients without LVSD (ejection fraction >50%) were included in the study. Participants were consequently selected. Detailed information regarding their medical records, sociodemographic and anthropometric data, and various psychological and lifestyle characteristics (physical activity, smoking habits, etc.) were recorded. In particular, nutritional habits, including coffee consumption, were evaluated using a semiquantitative food-frequency questionnaire. Multi-adjusted analysis revealed that in normotensive patients coffee consumption of 1-2 cups/day was associated with 88% (95% confidence interval, 0.02-0.84) lower likelihood of developing LVSD and consumption of >3 cups/day with 90% (95% confidence interval, 0.01-0.88) lower likelihood for LVSD, compared with no history of consumption of coffee and after adjusting for various confounders. In contrast, in hypertensive patients coffee consumption of >3 cups/day was associated with 4.5-fold higher likelihood for developing LVSD (95% confidence interval, 0.89-22.58) as compared with no history of coffee consumption. Coffee consumption has opposite effects on the likelihood of developing LVSD in post-acute coronary syndrome patients depending on their blood pressure levels.

Hydroxyhydroquinone-free coffee: a double-blind, randomized controlled dose-response study of blood pressure

BACKGROUND AND AIM

Coffee is rich in chlorogenic acids (CGA), whose metabolites may have beneficial effects such as anti-hypertensive effects. However, trial results concerning the effects of coffee on blood pressure (BP) are not consistent. A recent study suggested that hydroxyhydroquinone (HHQ), produced by the roasting of green coffee beans, inhibits the effect of CGA. In the present study, the dose-response for CGA in HHQ-free coffee on BP were investigated in mildly hypertensive men and women.

METHODS AND RESULTS

The trial design was a double-blind, randomized controlled trial, with five study groups including, control, zero-dose, low-dose, middle-dose and high-dose. The control beverage was identical to ordinary coffee. The others contained reduced HHQ levels, compared to ordinary coffee, and the CGA were adjusted in target concentration. A total of 203 subjects were randomly allocated. Each subject drank one cup of coffee per day. The study involved a screening and a baseline observation period of 6 weeks and an intervention period of 4 weeks. BP response showed CGA has an anti-hypertensive effect in a dose-dependent manner in HHQ-free coffee, and ordinary coffee showed almost no effect. As a result, a significant correlation between BP change and the three dose-response patterns was observed (p<0.001).

CONCLUSIONS

This study demonstrates a dose-dependent decrease in BP for CGA in HHQ-free coffee.

Neuroprotective effects of chlorogenic acid against apoptosis of PC12 cells induced by methylmercury

Chlorogenic acid (CGA) widely exists in edible and medicinal plants. We aimed to evaluate the effect of CGA on the protection from apoptosis by methylmercury (MeHg) in PC12 cells. Cell viability was evaluated by MTT assay. Apoptosis was assayed by flow cytometry detection. Caspase-3 activity was measured by confocal microscopy. Intracellular GSH levels were determined by bicinchoninic acid protein assay. Intracellular reactive oxygen species (ROS) was assessed by means of chloromethyl-dihydrodichlorofluorescein diacetate. Glutathione peroxidase (GPx) activity was determined by UV. In order to elucidate the action of CGA, the protective effects of CGA were compared to Vit.E. CGA was effective at protecting PC12 cells against MeHg-induced damage in dose-dependent manner. CGA not only suppressed the generation of ROS, the decrease of activity in GPx and the decrease of GSH, but also attenuated caspase-3 activation in PC12 cells by MeHg. CGA eventually protected PC12 cells against MeHg-induced apoptosis. The results highlighted that CGA may exert neuroprotective effects through its antioxidant actions.

Hydroxyhydroquinone interferes with the chlorogenic acid-induced restoration of endothelial function in spontaneously hypertensive rats

BACKGROUND

Coffee is a rich source of antioxidative polyphenols, but epidemiological studies and interventional trials have failed to demonstrate any clear beneficial effects of coffee consumption on hypertension. The interaction between hydroxyhydroquinone (HHQ) and 5-caffeoylquinic acid (CQA) was examined, in an attempt to understand the controversial effects of coffee on hypertension.

METHODS

Male Wistar Kyoto (WKY) rats or spontaneously hypertensive rats (SHRs, 14 weeks old) were divided into the following four groups; those on a control diet, 0.005% HHQ diet, 0.5% CQA diet, and HHQ plus CQA diet. The rats were fed the above diets for 8 weeks, and the tail arterial blood pressure was monitored in conscious rats at 2-week intervals. Urinary nitric oxide (NO) metabolites and hydrogen peroxide (H(2)O(2)) excretion were measured 8 weeks after the start of the experiment. Endothelium-dependent and -independent vasorelaxant responses and immunohistochemical staining for nitrotyrosine were examined in aortas.

RESULTS

HHQ inhibited the CQA-induced improvement in hypertension, urinary NO metabolites or H(2)O(2) excretion, endothelial dysfunction, and nitrotyrosine deposits in aortas in SHR. However, the administration of HHQ alone had little effect on either strain.

CONCLUSIONS

Based on the content ratio of HHQ and chlorogenic acids in coffee, HHQ interfered with the CQA-induced improvement in blood pressure and endothelial function in SHR. The results explain, at least in part, the conflicting action of coffee drinking on hypertension and vascular reactivity.

Association between coffee consumption and markers of inflammation and cardiovascular function during mental stress

BACKGROUND

Coffee is widely consumed in the Western diet and therefore has important implications for public health. Research findings pertaining to the effects of coffee consumption on cardiovascular health are conflicting, and the role of caffeine is not clear.

OBJECTIVE

To examine the relationship between coffee intake, inflammation and cardiovascular function at baseline and during mental stress, both cross-sectionally and after a 4-week period of withdrawal of coffee during which intake of caffeine was maintained.

METHODS

Eighty-five healthy, non-smoking men with varying coffee-drinking habits were recruited. Blood pressure, heart rate, and markers of inflammation [C-reactive protein (CRP), von Willebrand factor antigen (vWF)], were measured at baseline and during mental stress. These measures were repeated after a 4-week period of withdrawal of coffee, during which intake of caffeine was maintained. Habitual levels of coffee and caffeine consumption were assessed from a self-reported questionnaire, and saliva samples for the analysis of caffeine concentrations were collected regularly throughout the period of withdrawal, to confirm compliance.

RESULTS

Multiple linear regression analysis of pre-withdrawal data, adjusted for age, body mass index and intake of tea, red wine, fruit, vegetables, oily fish and dietary supplements revealed that coffee consumption was positively related to baseline systolic blood pressure, and increased heart rate and vWF responses to mental stress. Four weeks after withdrawal of coffee, the heightened vWF and heart rate responses to stress in habitual coffee drinkers persisted, whereas baseline systolic blood pressure had decreased. Total caffeine intake was unrelated to any measures of physiological function.

CONCLUSIONS

Habitual coffee consumption is associated with heightened acute vascular inflammatory responses to mental stress, although these effects are not affected by short-term abstinence from coffee. These findings suggest that the relationship between coffee and markers of cardiovascular risk may be explained by residual or unmeasured confounding factors.