Improved LC-MSn characterization of hydroxycinnamic acid derivatives and flavonols in different commercial mate (Ilex paraguariensis) brands. Quantification of polyphenols, methylxanthines, and antioxidant activity.

Yerba mate is a beverage rich in bioactive compounds popular in South America. Polyphenols and methylxanthines were qualitatively and quantitatively analyzed in four commercial brands of yerba mate, as well as the antioxidant capacity of the beverages. Using LC/MSn analysis, 58 polyphenols were observed of which 4-sinapoylquinic acid, di- and tri-methoxycinnamoylquinic acids, two isomers of trimethoxycinnamoylshikimic acid and four isomers of caffeoyl-2,7-anhydro-3-deoxy-2-octulopyranosonic acid were identified for the first time in mate. Additionally, 46 polyphenols and 2 methylxanthines were quantified by HPLC-DAD. Hydroxycinnamic acid derivatives and flavonols comprised 90% and 10% of mate phenols, respectively, 3-caffeoylquinic (26.8-28.8%), 5-caffeoylquinic (21.1-22.4%), 4-caffeoylquinic (12.6-14.2%) and 3,5-dicaffeoylquinic acids (9.5-11.3%) along with rutin (7.1-7.8%) were the most abundant polyphenols, whereas caffeine was the main methylxanthine (90%). Ilex paraguariensis is an important source of polyphenols with moderate methylxanthines content; therefore its high antioxidant capacity was mainly associated to its polyphenolic composition.

Polyphenol content, in vitro bioaccessibility and antioxidant capacity of widely consumed beverages.

BACKGROUND: Beverages prepared from antioxidant-rich plants are sources of polyphenols, the bioactivity of which depends on bioaccessibility in the gastrointestinal tract. This work evaluated the polyphenol content and antioxidant capacity of widely consumed beverages such as chamomile tea, yerba mate, a coffee blend (65% roasted: 35% green), and coffee-like substitutes such as chicory, malt and a soluble cereal mixture. Additionally, the bioaccessibility of the two beverages with the highest antioxidant capacity was evaluated using an in vitro digestion model. RESULTS: Total phenolic content ranged from 11.15 mg 200 mL-1 in chamomile tea, up to 154.53 mg 200 mL-1 in mate or 215.05 mg 200 mL-1 in the blend. These results correlated with the antioxidant capacity analysed by ferric reducing antioxidant power, oxygen radical scavenging capacity and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid methods. Yerba mate and the coffee blend showed an average polyphenol recovery after in vitro gastrointestinal digestion of 57% and 78%, respectively. Although both beverages showed similar phenolic composition, polyphenols in coffee were more stable than in yerba mate. Alkaline pH in the intestinal digestion stage was responsible for the observed reduction in polyphenol stability. CONCLUSION: Regular consumption of the studied beverages provides considerable amounts of antioxidants which are relatively stable after simulated digestion, and thus have the potential to prevent oxidative stress-related disorders. © 2017 Society of Chemical Industry.

The colonic metabolites dihydrocaffeic acid and dihydroferulic acid are more effective inhibitors of in vitro platelet activation than their phenolic precursors.

Cardiovascular disease (CVD) is the major cause of morbidity and mortality worldwide. The consumption of a healthy diet rich in polyphenols has been inversely associated with the development of CVD. This study evaluated the effects of green coffee bean extract (GCBE) and yerba mate phenolic extract (YMPE), the main phenolic and methylxanthine constituents (5-caffeoylquinic acid, 3,5-dicaffeoylquinic acid, caffeine, and theobromine), and their main metabolites (caffeic acid, ferulic acid, dihydrocaffeic acid (DHCA) and dihydroferulic acid (DHFA)) on platelet activation in vitro. Upon incubation with different doses (0.01-100 µg mL-1 or µM) of each compound, adenosine 5'-diphosphate-induced P-selectin expression and fibrinogen binding were determined using whole blood flow cytometry. Platelet P-selectin expression was significantly decreased by YMPE and all phenolic and methylxanthine constituents at physiological concentrations, compared with control, whereas fibrinogen binding on platelets was significantly increased. The colonic metabolites (DHCA and DHFA) had stronger inhibitory effects on P-selectin expression than their phenolic precursors, suggesting an increase in the efficacy to modulate platelet activation with the metabolism of the phenolic compounds.

Exhaustive Qualitative LC-DAD-MSn Analysis of Arabica Green Coffee Beans: Cinnamoyl-glycosides and Cinnamoylshikimic Acids as New Polyphenols in Green Coffee.

Coffee is one of the most consumed beverages in the world, due to its unique aroma and stimulant properties. Although its health effects are controversial, moderate intake seems to be beneficial. The present work deals with the characterization and quantification of polyphenols and methylxanthines in four Arabica green coffee beans from different geographical origins. The antioxidant activity was also evaluated. Forty-three polyphenols (cinnamic acid, cinnamoyl-amide, 5 cinammoyl-glycosides, and 36 cinnamate esters) were identified using LC-MSn. Among these, cinnamate esters of six different chemical groups (including two dimethoxycinnamoylquinic acid isomers, three caffeoyl-feruloylquinic acid isomers, caffeoyl-sinapoylquinic acid, p-coumaroyl-feruloylquinic acid, two caffeoylshikimic acid isomers, and trimethoxycinnamoylshikimic acid) in addition to five isomers of cinnamoyl-glycosides called caffeoyl-2,7-anhydro-3-deoxy-2-octulopyranosic acid (CDOA) are described for the first time in Arabica green coffee beans. Moreover, 38 polyphenols (6-7% w/w) and 2 methylxanthines (1.3% w/w) were quantified by HPLC-DAD. Caffeoylquinic was the most abundant group of compounds (up to 85.5%) followed by dicaffeoylquinic and feruloylquinic acids (up to 8 and 7%, respectively) and the newly identified cinnamoyl-glycosides (CDOA) (up to 2.5%). Caffeine was the main methylxanthine (99.8%), with minimal amounts of theobromine (0.2%). African coffees (from Kenya and Ethiopia) showed higher polyphenolic content than American beans (from Brazil and Colombia), whereas methylxanthine contents varied randomly. Both phenols and methylxanthines contributed to the antioxidant capacity associated with green coffee, with a higher contribution of polyphenols. We conclude that green coffee represents an important source of polyphenols and methylxanthines, with high antioxidant capacity.

Dihydrocaffeic acid, a major microbial metabolite of chlorogenic acids, shows similar protective effect than a yerba mate phenolic extract against oxidative stress in HepG2 cells.

The hepatoprotective effect of a yerba mate phenolic extract (YMPE), rich in chlorogenic acids, and its main circulating metabolites dihydrocaffeic (DHCA) and dihydroferulic (DHFA) acids were assessed in human hepatoma HepG2 cells subjected to oxidative damage induced by tert-butylhydroperoxide (t-BOOH). Direct treatment of HepG2 cells with realistic concentrations of YMPE (1, 10 and 50µg/mL), DHCA or DHFA (0.2, 1, 10µM) for 20h was not cytotoxic and significantly decreased ROS generation. Pre-treatment with YMPE and DHCA prevented the cytotoxicity and macromolecular damage induced by t-BOOH. Moreover, decreased levels of reduced glutathione (GSH), and increased ROS levels and antioxidant enzyme activity induced by t-BOOH were dose-dependently recovered. DHFA only showed a slight protection against cell cytotoxicity, lipid oxidation and GSH depletion. In conclusion, YMPE and one of its major microbial metabolites, DHCA, confer significant protection against oxidative damage, adding evidences to the beneficial health effects associated with mate intake.

Hypocholesterolaemic and antioxidant effects of yerba mate (Ilex paraguariensis) in high-cholesterol fed rats.

OBJECTIVE: To study the effect of mate (Ilex paraguariensis) on serum lipids and antioxidant status in normocholesterolaemic and hypercholesterolaemic rats. METHODS: Triglycerides (TG), total, LDL- and HDL-cholesterol levels, total antioxidant capacity (FRAP and ABTS assays), malondialdehyde (MDA) and protein carbonyls were analysed in serum, and MDA, glutathione and antioxidant enzyme activity in livers of rats drinking water or mate fed normal or cholesterol-cholic supplemented diets. RESULTS: ABTS, glutathione and antioxidant enzymes were not affected by any treatment. In normocholesterolaemic animals, mate had no effect on serum lipids or antioxidant status, yet it increased serum carbonyls and liver MDA concentrations. In hypercholesterolaemic rats, mate consumption had no effect on HDL-cholesterol or protein carbonyls, yet it showed a marked hypolipidaemic action, decreasing TG, total and LDL-cholesterol, and serum MDA levels that had been increased after consuming the high-cholesterol diet. CONCLUSION: Potential beneficial effect of mate on markers of cardiovascular risk seems to be restricted to hyperlipaemic animals.

Pharmacokinetics of caffeine and its metabolites in plasma and urine after consuming a soluble green/roasted coffee blend by healthy subjects.

Coffee is widely consumed worldwide; therefore, the methylxanthines contained in coffee, mainly caffeine (CF), are among the most abundant bioactive compounds in our diet. In the present work, the bioavailability and metabolism of methylxanthines in a commercial soluble green/roasted coffee blend was studied. After a 3-day restriction of methylxanthine-containing foods, fasting healthy subjects (12 men and women) consumed the coffee product containing 70.69mg CF and 0.119mg theobromine (TB). Plasma samples were taken before (t=0h) and after coffee consumption at different time points (0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 9, 10 and 12h). Urine was collected at baseline (-2-0h) and at different intervals (0-2, 2-5, 5-8, 8-12 and 12-24h). Samples were analyzed by HPLC-DAD and LC-MS-QToF, and pharmacokinetic parameters were calculated. CF was the main methylxanthine found in plasma (Cmax=10.50µM, Tmax=1.2h). In addition, seven methylxanthines and methyluric acids were detected between 0.5 and 12h after coffee intake, paraxanthine (PX) being the major metabolite (Cmax=3.36µM), followed by 1-methyluric acid (1-MU; Cmax=1.44µM) and 1-methylxanthine (1-MX; Cmax=1.27µM), identified in plasma samples for the first time. In 24h urine, eleven methylxanthines and methyluric acids were detected, 1-MU being the major metabolite (Cmax=150.52µM, Tmax=12h) amounting to 67.7% of the total urinary metabolites. In conclusion, a rapid absorption, metabolization and excretion of caffeine and its derived methylxanthines and methyluric acids have been observed after consumption of a green/roasted coffee product.

An aqueous pomegranate seed extract ameliorates oxidative stress of human hepatoma HepG2 cells.

BACKGROUND: Aqueous pomegranate seed extract (PSE), a by-product of the pomegranate juice industry, was recently identified as a potential antiglycative ingredient. Ellagic acid was proposed as the major polyphenol responsible for the antiglycative activity as exerted in in vitro models. However, there is no information on safety aspects of this extract in biological systems before its application as ingredient. The cytotoxicity of PSE (1-100 µg mL(-1) ) was evaluated by determining its effect on cell viability and redox status of cultured HepG2 cells. The protective effect of the PSE against oxidative stress induced by tert-butyl hydroperoxide (t-BOOH) was also investigated. RESULTS: No changes in cell integrity or intrinsic antioxidant status resulted from a direct treatment with aqueous PSE, even at high dosage. In addition, reactive oxygen species (ROS) induced by t-BOOH were reduced by 21% when cells were pretreated with 100 µg mL(-1) of aqueous PSE at 180 min. The range of concentrations investigated was effective in decreasing the ROS formation but not in a dose-dependent manner. CONCLUSION: Aqueous pomegranate seed extract enhances human hepatoma cells integrity and resistance to cope with a stressful situation at concentration up to 100 µg mL(-1) .

Hipertensión portal: desarrollo de una respuesta inflamatoria sistémica asociada a síndrome metabólico / Portal hypertension: Development of a systemic inflammatory response associated with metabolic syndrome

La hipertensión portal se caracteriza por un aumento de la presión venosa portal como resultado de la obstrucción del flujo sanguíneo portal. Una de las consecuencias de dicha obstrucción es el desarrollo de circulación colateral, la cual deriva una parte importante del flujo portal a la circulación sistémica. Entre las diferentes complicaciones que se asocian a la hipertensión portal en la rata destaca la esteatosis hepática, que a su vez se asocia a diferentes factores de riesgo como la obesidad, la diabetes, la hipercolesterolemia y la hipertrigliceridemia. Diversos mecanismos como la resistencia a la insulina, la liberación de citoquinas y el estrés oxidativo participan en el desarrollo de esta patología. El modelo experimental de hipertensión portal en la rata por triple ligadura parcial de la vena porta permite estudiar las complicaciones que se producen tanto a corto plazo o agudas, como a largo plazo o crónicas. La mayoría de las alteraciones esplácnicas y sistémicas que se producen en este modelo experimental son de naturaleza inflamatoria, y por esta razón el estudio de los mecanismos fisiopatológicos implicados tiene gran interés para la investigación de nuevas terapias antiinflamatorias (AU)

Portal hypertension (PH) is characterised by increase in portal venous pressure by obstruction of portal flow. As a consequence of PH, a collateral circulation is developed, which shifts an important part of portal flow to the systemic circulation. Furthermore, hepatic steatosis is another feature of PH in the rat, which is also, associated which different risk factors such as, obesity, diabetes, hypercholesterolemia and hypertrygliceridemia. Several mechanisms such as insulin resistance, cytokine production and oxidative stress participate in the development of this clinical pathology. An experimental model of pre-hepatic portal hypertension by triple partial portal vein ligation enables complications produced both short-term or acute and long-term or chronic outcome to be studied. Most of the splanchnic and systemic alterations produced in this experimental model are of an inflammatory nature, and for this reason the study of the physiological mechanisms involved are of great interest to the research of new anti-inflammatory therapies (AU)