Polyphenolic compounds, antioxidant capacity, and quinone reductase activity of an aqueous extract of Ardisia compressa in comparison to mate (Ilex paraguariensis) and green (Camellia sinensis) teas

The role of antioxidant versus pro-oxidant effects of green tea polyphenols in cancer prevention

Consumption of green tea (Camellia sinensis) may provide protection against chronic diseases, including cancer. Green tea polyphenols are believed to be responsible for this cancer preventive effect, and the antioxidant activity of the green tea polyphenols has been implicated as a potential mechanism. This hypothesis has been difficult to study in vivo due to metabolism of these compounds and poor understanding of the redox environment in vivo. Green tea polyphenols can be direct antioxidants by scavenging reactive oxygen species or chelating transition metals as has been demonstrated in vitro. Alternatively, they may act indirectly by upregulating phase II antioxidant enzymes. Evidence of this latter effect has been observed in vivo, yet more work is required to determine under which conditions these mechanisms occur. Green tea polyphenols can also be potent pro-oxidants, both in vitro and in vivo, leading to the formation of hydrogen peroxide, the hydroxyl radical, and superoxide anion. The potential role of these pro-oxidant effects in the cancer preventive activity of green tea is not well understood. The evidence for not only the antioxidant, but also pro-oxidant, properties of green tea is discussed in the present review.

Technological characterization and stability of Ilex paraguariensis St. Hil. Aquifoliaceae (Maté) spray-dried powder

The present work was designed to produce an Ilex paraguariensis spray-dried powder (SDP), in semi-industrial scale, in order to characterize its technological and chemical properties as well as to evaluate the thermal stability and photostability of the main polyphenol constituents. The yield of the spray-drying process was satisfactory (67%). The resulting SDP showed to be a material presenting spherical particles with a mean size of 19.6 μm, smooth surface, and good flow properties. The four polyphenol compounds previously reported for the species--neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, and rutin--were identified. Regarding the photostability test, the polyphenols present in the SDP proved to be stable against ultraviolet C radiation for 48 hours, independently of the packaging material. In the thermal stability test, the polyphenols were demonstrated to be hygroscopic and responsive to temperature (40°C) under an atmosphere of high relative humidity (75%) for 4 months, especially when the SDP was conditioned in permeable flasks. These findings demonstrate that heat and residual moisture content play an important role in the stability of the polyphenols and reinforce the relevance of conditioning SDP in humid tight packages under low temperatures.

Habitual intake of guaraná and metabolic morbidities: an epidemiological study of an elderly Amazonian population

The aim of the present study was to evaluate the associations of metabolic disorders and anthropometric and biochemical biomarkers of lipid, glucose and oxidative metabolism and the habitual ingestion of guaraná (Paullinia cupana, Mart. Var. sorbilis) by an elderly population residing in the Amazon Riverine region of the Maués municipality (Brazil). A case-controlled study was performed that included 637 elderly (≥60 years of age) patients classified as either those who habitually drank guaraná (GI, n = 421) or those who never drank guaraná (NG, n = 239) based upon their self-reported intake of guaraná. Indeed, the prevalence of various metabolic disorders was associated with guaraná ingestion. The prevalence of hypertension, obesity and metabolic syndrome in the GI group was lower than the prevalence found in the NG group. The NG group exhibited lower systolic and diastolic blood pressure values. The males in the GI group exhibited a lower waist circumference, on average, than the circumference found in the NG group, whereas the females in the GI group had lower cholesterol (total and LDL-c) levels than the control cohort. Additionally, a significant association was found between lower levels of advanced oxidative protein product (AOPP) and habitual guaraná consumption. The results constitute the first epidemiological study to suggest a potentially protective effect of habitual guaraná ingestion against metabolic disorders in elderly subjects.

Evaluation of the potential protective effects of ad libitum black grape juice against liver oxidative damage in whole-body acute X-irradiated rats

AIMS

The aim of this study was to evaluate the potential protective effects of ad libitum black grape (Vitis labrusca) juice against liver oxidative damage in whole-body acute X-irradiated rats.

MAIN METHODS

Animals were fed ad libitum and drank voluntarily black grape juice or placebo (isocaloric glucose and fructose solution) for 6 days before and 15 days following a 6 Gy X-irradiation from a 200 kV machine.

KEY FINDINGS

Irradiated animals receiving placebo showed a significant increase in the concentration of thiobarbituric acid-reactive substances (TBARS), a marker of lipid peroxidation, as well as a significant decrease in both Cu/Zn superoxide dismutase (Cu/ZnSOD) and glutathione peroxidase (GPx) activity and reduced glutathione concentration (GSH). Black grape juice supplementation resulted in a reversal of lipid peroxidation, Cu/ZnSOD activity, and GSH concentration, towards values not significantly differing from those in non-irradiated, placebo-supplemented rats. Poly(ADP-ribose) polymerase (PARP-1) and Cu/ZnSOD changes in protein expression were observed for irradiated rats. No change in p53 expression or DNA fragmentation was found.

SIGNIFICANCE

Ad libitum black grape juice intake is able to restore the liver primary antioxidant system against adverse effects due to whole-body acute X-irradiation in rats after 15 days post-irradiation. The results support using antioxidant supplements as a preventive tool against radiation-induced harm.

Antioxidant capacity and in vitro inhibition of adipogenesis and inflammation by phenolic extracts of Vaccinium floribundum and Aristotelia chilensis

Interest in berries from South America has increased due to their potential health benefits. The objective of this study was to characterize the anthocyanins and proanthocyanidins of Vaccinium floribundum and Aristotelia chilensis , total phenolics, and antioxidant capacity and to evaluate, in vitro, the ability of their phenolic extracts to reduce adipogenesis and lipid accumulation in 3T3-L1 adipocytes. The anti-inflammatory property of these extracts on RAW 264.7 macrophages was also investigated. Antioxidant capacity, measured as oxygen radical scavenging capacity and expressed as Trolox equivalents, was higher in the berries of A. chilensis. Phenolic extracts inhibited lipid accumulation by 4.0-10.8% when adipocytes were treated at maturity and by 5.9-37.9% when treated throughout differentiation. Furthermore, a proanthocyanidin-enriched fraction from V. floribundum significantly increased Pref-1 expression in preadipocytes. Phenolic extracts decreased the production of nitric oxide (3.7-25.5%) and prostaglandin E2 (9.1-89.1%) and the expression of inducible nitric oxide synthase (9.8-61.8%) and cycloxygenase-2 (16.6-62.0%) in lipopolysaccharide-stimulated RAW 264.7 macrophages. V. floribundum and A. chilensis phytochemicals limit adipogenesis and inflammatory pathways in vitro, warranting further in vivo studies.

Comparative in vitro bioactivities of tea extracts from six species of Ardisia and their effect on growth inhibition of HepG2 cells

AIM OF THE STUDY

Ardisia species, notably A. compressa, are used in some regions of the world as food or in traditional medicine for prevention and treatment of certain health conditions including liver disease. We investigated the chemical composition and relative anticancer potential of six Ardisia species [A. japonica (AJ), A. escallonioides (AES), A. mamillata (AM), A. compressa (AC), A. crenata (ACR), and A. elliptica (AE)].

MATERIALS AND METHODS

Antioxidant capacity, DNA human topoisomerase II catalytic inhibition, and cytotoxicity on human liver cancer cells (HepG2) were determined in vitro in tea extracts of the 6 Ardisia species evaluated. Selected pure phenolic compounds present in Ardisia species were also evaluated.

RESULTS

AC showed the highest topoisomerase II catalytic inhibition (IC(50)=12 microg/ml) and cytotoxicity (IC(50)=117 microg/ml) against HepG2 cells, followed by ACR and AJ. Total polyphenols ranged from 21 to 72 mg equivalents of gallic acid (GA)/g solid extract (SE). LC-MS analysis revealed the presence of GA, quercetin derivatives, ardisenone, ardisiaquinone, ardisianone, bergenin, norbergenin, and embelin. However, neither total polyphenol concentration nor antioxidant capacity correlated with anticancer capacity. Significant HepG2 cytotoxicity was also achieved by bergenin (IC(50)=18 microM) and embelin (IC(50)=120 microM). AC, bergenin, embelin, and quercetin showed a tendency to accumulate cells in the G1 phase and reduced G2/M leading to apoptosis.

CONCLUSIONS

Although the mechanism is not entirely clear, AC, ACR, and AJ are the Ardisia species with the greatest anticancer potential against liver cancer cells in vitro and deserve further investigation.

Profiling and characterization by LC-MSn of the chlorogenic acids and hydroxycinnamoylshikimate esters in maté (Ilex paraguariensis)

The chlorogenic acids of mate (Ilex paraguariensis) have been investigated qualitatively by LC-MS(n). Forty-two chlorogenic acids were detected and all characterized to regioisomeric level on the basis of their fragmentation pattern in tandem MS spectra, 24 of them for the first time from this source. Both chlorogenic acids based on trans- and cis-cinnamic acid substituents were identified. Assignment to the level of individual regioisomers was possible for eight caffeoylquinic acids (1-8), five dicaffeoylquinic acids (20-24), six feruloylquinic acids (9-14), two diferuloyl quinic acids (25 and 26), five p-coumaroylquinic acids (15-19), four caffeoyl-p-coumaroylquinic acids (34-37), seven caffeoyl-feruloylquinic acids (27-33), three caffeoyl-sinapoylquinic acids (38-40), one tricaffeoylquinic acid (41), and one dicaffeoyl-feruloylquinic acid (42). Furthermore, four caffeoylshikimates (43-46), three dicaffeoylshikimates (47-49), one tricaffeoylshikimate (51), and one feruloylshikimate (50) have been detected and shown to possess characteristic tandem MS spectra and were assigned by comparison to reference standards.

Energy Drinks: An Assessment of Their Market Size, Consumer Demographics, Ingredient Profile, Functionality, and Regulations in the United States

  The consumption of energy drinks is rapidly increasing, as demonstrated by their large market growth. The targeted demographic group is teenagers, young adults, 18 to 34 y old; although expansion into nontraditional markets is also occurring. It is claimed that energy drinks can offer an increased energy boost related to their ingredient profile of caffeine, taurine, herbal extracts, and vitamins. Research suggests that energy drink formulations, in addition to increasing energy utilization, may also improve mood, enhance physical endurance, reduce mental fatigue, and increase reaction time. However, in most cases, the corresponding mechanisms of action are not clear. In addition, concerns have been raised over their safety and with a currently weak regulatory environment, efforts need to be made to ensure consumer safety. The objective of this article is to review the current U.S. energy drink market with emphasis on its market size, target demographic, active ingredients, potential benefits, safety, and regulations.

Toxicological effects of ultraviolet radiation on lymphocyte cells with different manganese superoxide dismutase Ala16Val polymorphism genotypes

The aim of this study was to investigate whether there is a differential response of lymphocytes from healthy MnSOD genotype subjects to oxidative stress. We used UV radiation as a toxic agent due to its genotoxic effects associated with chromosome aberrations caused by breaks in the DNA strands. Cellular growth rate, cell viability, mitotic index, chromosomal instability and biomarkers of oxidative metabolism were analysed in lymphocyte cells from healthy adults with different Ala16Val MnSOD polymorphisms that produce tree genotypes: AA, VV and AV. We found a differential response to UV exposure in cultures of lymphocyte cells from Ala16Val genotype donors. In general, AA cell cultures presented higher viability and mitotic index and lower TBARS levels than VV and AV cells for both the control and UV exposure groups. However, when we compared the DNA damage among the three genotypes, AA lymphocyte cells presented the highest damage from UV exposure. These data suggest that the Ala16Val polymorphism affects the response of cellular oxidative metabolism in different ways.

Isoalantolactone from Inula helenium caused Nrf2-mediated induction of detoxifying enzymes

Our previous study demonstrated that methanolic extract of Inula helenium (Elecampane) has the potential to induce detoxifying enzymes such as NAD(P)H:(quinone acceptor) oxidoreductase 1 (EC 1.6.99.2) (NQO1, QR) activity and glutathione S-transferase (GST) and found isoalantolactone and alantolactone as the active components. In this study we investigated the detoxifying enzyme-inducing potential of isoalantolactone, which is present in I. helenium and has a structure similar to that of alantolactone. The compound induced QR in a dose-dependent manner in both Hepa1c1c7 cells and its mutant BPRc1 cells lacking the arylhydrocarbon receptor translocator. Like with most phase 2 enzyme inducers, other phase 2 detoxifying enzymes, including GST, glutathione reductase, gamma-glutamylcysteine synthetase, and heme oxygenase-1, were also induced by isoalantolactone in a dose-dependent manner in the cultured cells. Furthermore, isoalantolactone caused a proportionate increase in luciferase activity depending upon concentration and exposure time in the reporter assay in which HepG2-C8 cells, transfectants carrying antioxidant response element-luciferase gene, were used. The nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) was stimulated by the compound and attenuated by phosphatidylinositol 3-kinase inhibitors such as LY294002 and wortmannin. In conclusion, isoalantolactone is a candidate for chemoprevention and acts as potent phase 2 enzyme inducer by stimulating the accumulation of Nrf2 in the nucleus.

Antioxidant activities of flavonol derivatives from the leaves and stem bark of Scutia buxifolia Reiss

This study evaluated the antioxidant activities in the leaves and stem bark fractions of Scutia buxifolia. Cerebral lipid peroxidation (TBARS) was induced by Fe(II) and radical-scavenging activity was determined by DPPH method. Folin-Ciocalteu was used to determine phenolic contents. Quercetin, quercitrin, isoquercitrin and rutin were isolated from leaf ethyl acetate fraction and their levels were measured by high performance liquid chromatography-photodiode array detector. IC(50) (DPPH) varied from 4.35+/-1.30 to 29.55+/-0.54 microg/mL for stem bark and from 6.50+/-0.40 to 30.54+/-1.14 in the leaves. Ethyl acetate and butanolic fractions caused a sharp fall in TBARS production with IC(50) from 2.93+/-2.17 to 40.46+/-2.51 microg/mL for the leaves and 0.66+/-0.17 to 27.3+/-1.23 for the stem bark. Results obtained indicated that S. buxifolia has a great potential to prevent disease caused by the overproduction of free radicals and also it might be used as a potential source of natural antioxidant agents.

Dietary phenolics: chemistry, bioavailability and effects on health

There is much epidemiological evidence that diets rich in fruit and vegetables can reduce the incidence of non-communicable diseases such as cardiovascular diseases, diabetes, cancer and stroke. These protective effects are attributed, in part, to phenolic secondary metabolites. This review summarizes the chemistry, biosynthesis and occurrence of the compounds involved, namely the C6-C3-C6 flavonoids-anthocyanins, dihydrochalcones, flavan-3-ols, flavanones, flavones, flavonols and isoflavones. It also includes tannins, phenolic acids, hydroxycinnamates and stilbenes and the transformation of plant phenols associated with food processing (for example, production of black tea, roasted coffee and matured wines), these latter often being the major dietary sources. Events that occur following ingestion are discussed, in particular, the deglycosylation, glucuronidation, sulfation and methylation steps that occur at various points during passage through the wall of the small intestine into the circulatory system and subsequent transport to the liver in the portal vein.We also summarise the fate of compounds that are not absorbed in the small intestine, but which pass into the large intestine where they are degraded by the colonic microflora to phenolic acids, which can be absorbed into the circulatory system and subjected to phase II metabolism prior to excretion. Initially, the protective effect of dietary phenolics was thought to be due to their antioxidant properties which resulted in a lowering of the levels of free radicals within the body.However, there is now emerging evidence that themetabolites of dietary phenolics,which appear in the circulatory systemin nmol/L to low mmol/L concentrations, exertmodulatory effects in cells through selective actions on different components of the intracellular signalling cascades vital for cellular functions such as growth, proliferation and apoptosis. In addition, the intracellular concentrations required to affect cell signalling pathways are considerably lower than those required to impact on antioxidant capacity. The mechanisms underlying these processes are discussed.

Comparative study of antioxidant properties and total phenolic content of 30 plant extracts of industrial interest using DPPH, ABTS, FRAP, SOD, and ORAC assays

Aqueous extracts of 30 plants were investigated for their antioxidant properties using DPPH and ABTS radical scavenging capacity assay, oxygen radical absorbance capacity (ORAC) assay, superoxide dismutase (SOD) assay, and ferric reducing antioxidant potential (FRAP) assay. Total phenolic content was also determined by the Folin-Ciocalteu method. Antioxidant properties and total phenolic content differed significantly among selected plants. It was found that oak (Quercus robur), pine (Pinus maritima), and cinnamon (Cinnamomum zeylanicum) aqueous extracts possessed the highest antioxidant capacities in most of the methods used, and thus could be potential rich sources of natural antioxidants. These extracts presented the highest phenolic content (300-400 mg GAE/g). Mate (Ilex paraguariensis) and clove (Eugenia caryophyllus clovis) aqueous extracts also showed strong antioxidant properties and a high phenolic content (about 200 mg GAE/g). A significant relationship between antioxidant capacity and total phenolic content was found, indicating that phenolic compounds are the major contributors to the antioxidant properties of these plants.

Yerba Maté (Ilex paraguariensis) aqueous extract decreases intestinal SGLT1 gene expression but does not affect other biochemical parameters in alloxan-diabetic Wistar rats

Yerba maté (Ilex paraguariensis) is rich in polyphenols, especially chlorogenic acids. Evidence suggests that dietary polyphenols could play a role in glucose absorption and metabolism. The aim of this study was to evaluate the antidiabetic properties of yerba maté extract in alloxan-induced diabetic Wistar rats. Animals (n = 41) were divided in four groups: nondiabetic control (NDC, n = 10), nondiabetic yerba maté (NDY, n = 10), diabetic control (DC, n = 11), and diabetic yerba maté (DY, n = 10). The intervention consisted in the administration of yerba maté extract in a 1 g extract/kg body weight dose for 28 days; controls received saline solution only. There were no significant differences in serum glucose, insulin, and hepatic glucose-6-phosphatase activity between the groups that ingested yerba maté extract (NDY and DY) and the controls (NDC and DC). However, the intestinal SGLT1 gene expression was significantly lower in animals that received yerba maté both in upper (p = 0.007) and middle (p < 0.001) small intestine. These results indicate that bioactive compounds present in yerba maté might be capable of interfering in glucose absorption, by decreasing SGLT1 expression.

Effect of growing and drying conditions on the phenolic composition of mate teas (Ilex paraguariensis)

Mate tea ( Ilex paraguariensis) has been used for centuries and is widely consumed in Brazil, Argentina, Paraguay, and Uruguay. The aim of the present study was to determine how growing and drying conditions affect the phenolic concentration and antioxidant capacity of 15 Mate teas from forest or plantation cultivations, dried either with hot air or wood smoke. The total polyphenol concentration determined with Folin-Ciocalteu ranged from 100.3 +/- 5.5 to 179.7 +/- 3.6 mg equiv chlorogenic acid/g dry leaves. The antioxidant capacity according to the oxygen radical absorbance capacity assay ranged from 1.5 +/- 0.3 to 4.1 +/- 0.1 mmol Trolox equiv/g dry leaves. Ten phenolic compounds were identified and correlated with antioxidant capacity ( R (2) = 0.80). Principle component analysis and multivariate linear regression were conducted to assess the effect of growing and drying conditions. Sun-exposed (plantation grown) Mate teas exhibited higher levels of all polyphenols as compared to shaded (forest grown) Mate teas ( P < 0.05). Lower rainfall, temperature, and drying conditions had varying effects on the phenolics. On average, plantation grown Mate teas had a greater concentration of phenolics than forest grown teas. Thus, plantation grown Mate teas represent better potential sources for their commercial extraction.

Consumption of mate tea (Ilex paraguariensis) decreases the oxidation of unsaturated fatty acids in mouse liver

Mate (Ilex paraguariensis) is rich in polyphenolic compounds, which are thought to contribute to the health benefits of tea. Mate tea was administered orally to mice at a dose of 0·5, 1·0 or 2·0 g/kg for 60 d, and changes both in serum lipid concentration and fatty acid composition of liver and kidney were examined. The effects of mate tea on serum and tissue lipid peroxidation were assessed by the evaluation of thiobarbituric acid-reactive substances (TBARS). In tea-consuming mice, both MUFA (18 : 1n-9) and PUFA (18 : 2n-6 and 20 : 4n-6) were increased (P < 0·05) in the liver lipid (approximately 90 and 60 %, respectively), whereas only MUFA (approximately 20 %) were increased in the kidney lipid. The most altered PUFA class wasn-6 PUFA, which increased by approximately 60–75 % (P < 0·05). This difference in the fatty acid profile in the liver is reflected in the increased PUFA:SFA ratio. Consistent with these results, mice fed with mate tea had much lower TBARS in the liver. No differences (P>0·05) were found in the levels of serum cholesterol, HDL-cholesterol and TAG under the conditions of the present study. These results suggest that treatment with mate tea was able to protect unsaturated fatty acids from oxidation and may have selective protective effects within the body, especially on the liver.

Cancer chemoprevention and chemotherapy: dietary polyphenols and signalling pathways

Prevention of cancer through dietary intervention recently has received an increasing interest, and dietary polyphenols have become not only important potential chemopreventive, but also therapeutic, natural agents. Polyphenols have been reported to interfere at the initiation, promotion and progression of cancer. They might lead to the modulation of proteins in diverse pathways and require the integration of different signals for the final chemopreventive or therapeutic effect. Polyphenols have been demonstrated to act on multiple key elements in signal transduction pathways related to cellular proliferation, differentiation, apoptosis, inflammation, angiogenesis and metastasis; however, these molecular mechanisms of action are not completely characterized and many features remain to be elucidated. The aim of this review is to provide insights into the molecular basis of potential chemopreventive and therapeutic activities of dietary polyphenols with emphasis in their ability to control intracellular signalling cascades considered as relevant targets in a cancer preventive approach.

Yerba Mate Tea (Ilex paraguariensis): a comprehensive review on chemistry, health implications, and technological considerations

Yerba Mate tea, an infusion made from the leaves of the tree Ilex paraguariensis, is a widely consumed nonalcoholic beverage in South America which is gaining rapid introduction into the world market, either as tea itself or as ingredient in formulated foods or dietary supplements. The indigenous people have used it for centuries as a social and medicinal beverage. Yerba Mate has been shown to be hypocholesterolemic, hepatoprotective, central nervous system stimulant, diuretic, and to benefit the cardiovascular system. It has also been suggested for obesity management. Yerba Mate protects DNA from oxidation and in vitro low-density lipoprotein lipoperoxidation and has a high antioxidant capacity. It has also been reported that Yerba Mate tea is associated to both the prevention and the cause of some types of cancers. Yerba Mate has gained public attention outside of South America, namely the United States and Europe, and research on this tea has been expanding. This review presents the usage, chemistry, biological activities, health effects, and some technological considerations for processing of Yerba Mate tea. Furthermore, it assesses in a concise and comprehensive way the potential of Ilex paraguariensis as a source of biological compounds for the nutraceutical industry.

Protective effects of mate tea (Ilex paraguariensis) on H2O2-induced DNA damage and DNA repair in mice

Yerba mate (Ilex paraguariensis) is rich in several bioactive compounds that can act as free radical scavengers. Since oxidative DNA damage is involved in various pathological states such as cancer, the aim of this study was to evaluate the antioxidant activity of mate tea as well as the ability to influence DNA repair in male Swiss mice. Forty animals were randomly assigned to four groups. The animals received three different doses of mate tea aqueous extract, 0.5, 1.0 or 2.0 g/kg, for 60 days. After intervention, the liver, kidney and bladder cells were isolated and the DNA damage induced by H(2)O(2) was investigated by the comet assay. The DNA repair process was also investigated for its potential to protect the cells from damage by the same methodology. The data presented here show that mate tea is not genotoxic in liver, kidney and bladder cells. The regular ingestion of mate tea increased the resistance of DNA to H(2)O(2)-induced DNA strand breaks and improved the DNA repair after H(2)O(2) challenge in liver cells, irrespective of the dose ingested. These results suggest that mate tea could protect against DNA damage and enhance the DNA repair activity. Protection may be afforded by the antioxidant activity of the mate tea's bioactive compounds.

Dietary fiber content and associated antioxidant compounds in Roselle flower (Hibiscus sabdariffa L.) beverage

The beverage of Hibiscus sabdariffa flowers is widely consumed in Mexico. Polyphenols contained in plant foods are frequently associated with dietary fiber. The aim of this work is to quantify the dietary fiber, associated polyphenols, and antioxidant capacity of the Roselle flower and the beverage traditionally prepared from it and its contribution to the Mexican diet. Roselle flower contained dietary fiber as the largest component (33.9%) and was rich in phenolic compounds (6.13%). Soluble dietary fiber was 0.66 g/L in beverage, and 66% of total extractable polyphenols contained in Roselle flower passed to the beverage and showed an antioxidant capacity of 335 micromoL trolox equivalents/100 mL beverage measured by ABTS. These data suggest that Roselle flower beverage intake in the Mexican diet may contribute around 166 and 165 mg/per serving to the intake of dietary fiber and polyphenols, respectively. The health benefits from consumption of Hibiscus beverage could be of considerable benefit to the whole population.

Phenolic antioxidants identified by ESI-MS from Yerba maté (Ilex paraguariensis) and green tea (Camelia sinensis) extracts

Aqueous extracts of green yerba maté (Ilex paraguariensis) and green tea (Camellia sinensis) are good sources of phenolic antioxidants, as already described in the literature. The subject of this study were organic extracts from yerba maté, both green and roasted, and from green tea. Their phenolic profiles were characterized by direct infusion electrospray insertion mass spectrometry (ESI-MS) and their free radical scavenging activity was determined by the DPPH assay. Organic extracts containing phenolic antioxidants might be used as natural antioxidants by the food industry, replacing the synthetic phenolic additives used nowadays. Ethanolic and aqueous extracts from green yerba maté, roasted yerba maté and green tea showed excellent DPPH scavenging activity (>89%). The ether extracts from green and roasted yerba maté displayed a weak scavenging activity, different from the behavior observed for the green tea ether extract. The main phenolic compounds identified in green yerba maté water and ethanolic extracts were: caffeic acid, quinic acid, caffeoyl glucose, caffeoylquinic acid, feruloylquinic acid, dicaffeoylquinic acid and rutin. After the roasting process two new compounds were formed: caffeoylshikimic acid and dicaffeoylshikimic acid. The ethanolic extracts from yerba maté, both roasted and green, with lower content of phenolic compounds (3.80 and 2.83 mg/mL) presented high antioxidant activity and even at very low phenolic concentrations, ether extract from GT (0.07 mg/mL) inhibited DPPH over 90%.

Synthesis and properties of lanthanide(III) complexes with 4-hydroxy-3,5-dimethoxybenzoic acid

Complexes of yttrium(III) and lanthanides(III) with 4-hydroxy-3,5-dimethoxybenzoic (syringic) acid were obtained as solids with metal to ligand mole ratio of 1: 3. The compounds were characterized by elemental analysis, IR spectroscopy, X-ray diffraction patterns, solubility, and thermal studies. The complexes are sparingly soluble in water and stable at room temperature. Compounds of light lanthanides (from La to Nd) are hydrated and they crystallize in a triclinic system. When heated, they lose water molecules in one step and in the next step they decompose to oxides. Complexes of yttrium and other lanthanides are anhydrous and crystallize in a monoclinic system. They are stable up to 300°C and then decompose to oxides. As the coordination number of lanthanide ions is usually equal to 9 or 8, one can suppose that hydroxy or methoxy groups take part in the coordination of these metal ions.

Determination of trace elements in herbal tea products and their infusions consumed in Thailand

Nineteen elements, Mg, Al, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Sr, Sb, Ba, As, Cd, Hg, and Pb, were determined in three types of popular herbal tea products, Gynostemma pentaphyllum, Camellia sinensis, and Morus alba. These herbal tea products, both imported and locally made products, are widely consumed in Thailand and worldwide. Microwave-assisted acid digestion was used for all of the samples, and the element contents were determined by ICP-MS. The concentrations of all elements varied among these herbal teas. Ca and Mg were the most abundant elements in all herbal samples (1384-34070 and 783-7739 mg/kg, respectively). Most elements in these herbal tea powders were also released into the infusions at different percentages depending on types of herbs. G. pentaphyllum infusion contained essential elements (Mg, Ca, V, and Fe) at higher levels than C. sinensis and M.alba infusions. Al and Ni were present at high levels in C. sinensis infusion, and Cd level was high in M. alba infusion. The daily intake of all elements from these herbal tea infusions (three cups/day) is still within the average daily intake. Therefore, it may not produce any health risks for human consumption, if other sources of toxic metal contaminated food are not taken at the same time.

When quinones meet amino acids: chemical, physical and biological consequences

Quinones and amino acids are usually compartmentally separated in living systems, however there are several junctions in which they meet, react and influence. It occurs mainly in wounded, cut or crushed plant material during harvest, ensiling or disintegrating cells. Diffusing polyphenols are oxidized by polyphenol oxidases (PPOs) to quinonic compounds, which associate reversibly or irreversibly with amino acids and proteins. The reaction takes place with the free nucleophilic functional groups such as sulfhydryl, amine, amide, indole and imidazole substituents. It results in imine formation, in 1,4-Michael addition via nitrogen or sulphur and in Strecker degradation forming aldehydes. The formation and activity of quinone-amino acids conjugates influences the colour, taste, and aroma of foods. Physical and physiological phenomena such as browning of foods, discoloration of plants during processing, alteration of solubility and digestibility, formation of humic substances, germicidal activity, cytotoxicity and more occur when quinones from disintegrating cells meet amino acids. The mechanisms of toxicity and the pathways by which PCBs may be activated and act as a cancer initiator include oxidation to the corresponding quinones and reaction with amino acids or peptides. Sclerotization of insect cuticle is a biochemical process involving also the reaction between quinones and amino acid derivatives.

Catalytic inhibition of human DNA topoisomerase by phenolic compounds in Ardisia compressa extracts and their effect on human colon cancer cells

Plant polyphenols, as those present in teas, have been associated with several health benefits. In this study, the main objectives were to identify and characterize the phenolic compounds in Ardisia compressa tea (AC) responsible for topoisomerase inhibition using a bioassay directed approach and modern analytical techniques, and to determine the cytotoxicity against human colon carcinoma cells. Inhibition of topoisomerase was determined by yeast and human topoisomerase biochemical assays. Identification and characterization of AC phenolic compounds were carried out using combined HPLC, MS and NMR techniques. Cytotoxicity studies were conducted using two human colorectal adenocarcinoma cell lines, HT-29 and Caco-2. LC-MS analysis of AC confirmed the presence of gallic acid, epicatechin gallate, several proanthocyanidin dimers, kaempferol, naringenin and ardisin derivatives. Topoisomerase II catalytic inhibitory activity of AC was due mainly to phenolic compounds extracted in the butanolic fraction (IC50: 1.33 microg/ml). Purification of this fraction resulted in the isolation of several compounds: peak 10 (IC50: 8.32 microg/ml), peaks 12/14 (IC75: 2.85 microg/ml) and peak 15 (IC50: 7.16 microg/ml). Characterization of peak 15, the most active fraction, led to the isolation of a naringenin isomer (C15H12O5), which had a significantly higher catalytic anti-topoisomerase II activity (IC50: 7.16 microg/ml) than commercial naringenin (IC50: 88.1 microg/ml). AC was cytotoxic to HT-29 (IC50: 57.9+/-11.6 microg/ml) and Caco-2 cells (IC50: 81.0+/-27.5 microg/ml). These findings provide basic information and suggest the potential use of active flavonoids in Ardisia compressa tea as chemopreventive agents.

Aqueous extract of Ilex paraguariensis attenuates the progression of atherosclerosis in cholesterol-fed rabbits

Ilex paraguariensis aqueous extract (mate) is an antioxidant-rich beverage widely consumed in South American countries. Here we questioned whether mate could reduce the progression of atherosclerosis in 1% cholesterol-fed rabbits. New Zealand White male rabbits (n = 32) were divided into four groups: control (C, n = 5), control-mate (CM, n = 5), hypercholesterolemic (HC, n = 11) and hypercholesterolemic-mate (HCM, n = 11). The daily water and mate extract consumption was approximately 400 ml. After 2 months of treatment, mate intake did not change the lipid profile or hepatic cholesterol content of control or hypercholesterolemic rabbits (p < 0.05). However, the atherosclerotic lesion area was considerably smaller in the hypercholesterolemic-mate group (HCM, 35.4% vs. HC, 60.1%; p < 0.05). In addition, the aortic cholesterol content was around half that of the HC group (HCM, 36.8 vs. HC, 73.9 microg/mg of protein, p < 0.05). In spite of this, the thiobarbituric acid-reactive substances (TBARS) in the atherosclerotic aorta, liver and serum, and the activity of the antioxidant enzymes in liver and aorta did not differ among groups (p > 0.05). The results showed that Ilex paraguariensis extract can inhibit the progression of atherosclerosis in cholesterol-fed rabbits, although it did not decrease the serum cholesterol or aortic TBARS and antioxidant enzymes.

Correlation between theIn Vitro antioxidant activity and polyphenol content of aqueous extracts from bulgarian herbs

The water phase antioxidant activity of extracts from 23 Bulgarian medicinal plants was studied in relation to their polyphenol content in comparison with mate, black tea, honeybush and rooibos foreign species. Antioxidant activity was measured by the ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)) cation radical decolorization assay, and the total polyphenol content was assayed according to the Folin-Ciocalteu method. Five Bulgarian plant extracts exhibited higher antioxidant activity than that of mate, which is 21.7% of all Bulgarian herbs included in this study. These were Alchemilla vulgaris L. (4.79 +/- 0.14 mm), Sambucus ebulus L. (4.03 +/- 0.07 mm), Mentha spicata L. (3.90 +/- 0.03 mm), Fragaria vesca L. (3.74 +/- 0.06 mm), Crataegus monogyna Jacq. (3.63 +/- 0.05 mm). Another eight Bulgarian medicinal plant extracts exhibited an intermediate antioxidant activity - lower than that of mate and higher than that of honeybush, which makes 34.8% of all Bulgarian herbs included in the study. More than half of the herbal extracts included in the present study exhibited antioxidant activity higher than or comparable to the reference foreign plants. A positive correlation (r = 0.92) between antioxidant activity and polyphenol content was found, suggesting that the antioxidant capacity of the aqueous plant extracts is due to a great extent to their polyphenols.

Oral magnetic resonance imaging contrast agent based onIlex paraguayensis herbal extract

In this article we demonstrate the potential of herbal extracts from yerba mate (Ilex paraguayensis) as an oral contrast agent for MRI. At typical drinking concentrations, yerba mate acts as a "biphasic" contrast agent with T1 weighting at short echo times and T2 weighting at echo times greater than about 40 ms. Based on data obtained from X-ray fluorescence elemental analysis, NMR relaxometry, and ESR we identify the relaxation agent in the extract as a low-molecular-weight manganese complex. Yerba mate exhibits an unusually high manganese content that is readily available for hot water extraction. Despite the high elemental manganese levels in I. paraguayensis extract, no manganese-related toxicity of yerba mate has been observed even among heavy yerba mate drinkers, indicating that the manganese in the extract has only a very low bioavailability. Imaging results on staff and patient volunteers demonstrate good contrasting of the GI tract. The relaxation studies of the contrast agent show a sensitivity to pH that is consistent with imaging results from stomach and small bowel.

Ilex paraguariensis extracts inhibit AGE formation more efficiently than green tea

Glycation, the nonenzymatic adduct formation between sugar dicarbonyls and proteins, is one key molecular basis of diabetic complications due to hyperglycemia. Given the link between glycation and oxidation, we hypothesized that herbal extracts with a high concentration of antioxidant phenolics might possess significant in vitro antiglycation activities as well. The aim of the present study was to address the hypothesis that polyphenol-rich Ilex paraguariensis (IP) extracts are capable of inhibiting advanced glycation end-products (AGEs) formation and to compare the potency of these extracts with green tea and with the standard antiglycation agent aminoguanidine. When we studied the effects of IP extract on AGE fluorescence generated on bovine serum albumin (BSA) by glycation with methylglyoxal, a dose-dependent effect that reaches 40% at 20 mul/ml of extract was demonstrated. Green tea did not display any significant effect. IP polyphenols are about 2- to 2.5-fold higher in our preparations compared with green tea. The effect of IP, therefore, may be due not only to the higher concentrations but to the different composition in phenolics of the two botanical preparations as well. To better discriminate between an antioxidant or a carbonyl quenching mechanism of action, we explored tryptophan fluorescence and cross-linking by sodium dodecyl sulfate polyacrylamide gel (SDS-PAGE) electrophoresis. The conformational changes induced by glycation and substitution of positive charges in arginine and/or lysine produce a decrease in tryptophan fluorescence. We show that incubation of BSA with methylglyoxal produces dramatic changes in tryptophan fluorescence that are prevented by aminoguanidine. This also prevents the downstream effect of AGE formation. Neither green tea nor IP extracts displayed any significant effect which rules out any significant participation as inhibitors in the first phase of the glycation cascade. The results from the SDS-PAGE serve to confirm the above-mentioned data. The effect is therefore due mainly to an inhibition of the second phase of the glycation reactions, namely the free-radical mediated conversion of the Amadori products to AGE. Taken together our results demonstrate a significant, dose-dependent effect of water extracts of I. paraguensis on AGE adducts formation on a protein model in vitro, whereas green tea displays no significant effect. The inhibition of AGE formation was comparable to that obtained by using millimolar concentrations of the standard antiglycation agent aminoguanidine.

Antioxidant activities of extracts from Barkleyanthus salicifolius (Asteraceae) and Penstemon gentianoides (Scrophulariaceae)

Various extracts of the aerial parts of Barkleyanthus salicifolius (Asteraceae) and Penstemon gentianoides (Scrophulariaceae) have been used in folk medicine to treat many ailments, particularly inflammation and migraine. Neither the bioactive components responsible nor the mechanisms involved have been evaluated. Here are reported antioxidant activities of their methanol, dichloromethane, and ethyl acetate extracts. Samples were evaluated for oxygen radical absorption capacity (ORAC), ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, and inhibition of the formation of thiobarbituric acid reactive species (TBARS), a measure of lipid peroxidation. Antioxidant activities were strongly correlated with total polyphenol content. The most active extracts from P. gentianoides in scavenging DPPH radicals and inhibiting TBARS formation were the methanol extract (A) and a further ethyl acetate extract of this (E). Partition E was further divided into eight fractions, and both E and the fractions were compared for activity against butylated hydroxytoluene, quercetin, and tocopherol. Partition E and the most active fractions, 5 and 6, were found to have I(50) values of 14.1, 38.6, and 41.8 ppm, respectively, against DPPH and 18.5, 26.0, and 12.7 ppm, respectively, against TBARS formation. Consistent with this finding, partition E and fractions 4-6 had the greatest ORAC and FRAP values. These results show that these plants could be useful antioxidant sources.

Investigations of the antioxidant properties of plant extracts using a DNA-electrochemical biosensor

In this work, the results of a method based on an electrochemical biosensor to detect DNA damage in vitro for the evaluation of the antioxidant properties of plant extracts are reported. The biosensor consisted of a dsDNA immobilized on a screen-printed electrode surface (SPE). DNA damage was promoted by the generation of the *OH radicals via Fenton-type reaction. The interaction of the radical species with immobilised DNA in the absence and presence of antioxidants was evaluated by means of changes in the guanine oxidation peak obtained by square wave voltammetry. The results demonstrated that the DNA-based biosensor is suitable as a rapid screening test for the evaluation of antioxidant properties of samples.

Ilex paraguariensis extracts are potent inhibitors of nitrosative stress: A comparative study with green tea and wines using a protein nitration model and mammalian cell cytotoxicity

Due to the increasing importance of nitrosative stress in pathology and the efficacy displayed by flavonoids in cancelling the effects of peroxynitrite, we decided to conduct a comparative study of three commonly used beverages with the highest polyphenol contents and proven antioxidant properties: mate (Ilex paraguariensis); green tea (Camelia sinensis) extracts and white and red wines of the main varietals. We directly evaluated and compared the extracts and wines as protein nitration inhibitors using 3-nitrotyrosine as a biomarker, we studied the extracts as protectors from OONO-induced cytotoxicity in two mammalian cell lines. Both green tea and mate extracts have a high polyphenol content, in the case of Ip, its higher concentration and higher free radical quenching activity on the DPPH assay may be mainly due to the sui generis extraction procedure. When BSA was incubated in the presence of SIN-1, a time and dose dependent nitration of the protein is clearly shown. Co-incubation of BSA with Ip, green tea or red wines led to a dose dependent inhibition of the effect. Ip displayed the highest inhibitory activity, followed by red wines and the green tea. Dilutions as low as 1/1500 produced more than 80% inhibition of albumin nitration. When we studied peroxynitrite-induced cytotoxicity in murine RAW 264.7 macrophages and 31EG4 mammary cells., we found a potent, dose-dependent protective effect that was Ilex paraguariensis > red wines > green tea. Taken together, our results indicate that when the herbal preparations studied here are prepared the way they are usually drunk, Ip displays the highest inhibition of protein nitration, and the highest promotion of cell survival, whereas green tea or red wines display significant but lesser effects at the same concentrations. Further studies aiming at isolation of the active principles and assessment of their bioavailability are warranted.

Analysis of natural flavonoids by microchip-micellar electrokinetic chromatography with pulsed amperometric detection

Catechins (catechin and other derivatives) are naturally occurring flavonoids present in a number of plants and foods. They are also part of numerous nutraceutical formulations because they are believed to have antioxidant, cancer chemo-preventative, anti-inflammatory and antimicrobial properties. The determination of catechins has traditionally been performed by HPLC. However, this methodology is both time and sample intensive and generates large amounts of organic solvent waste. In the current report, an application of MEKC using a PDMS microchip is presented for the analysis of catechins. The system uses pulsed amperometric detection for direct analysis of important naturally occurring catechins. The effect of pH, surfactant concentration, detection potential and signal stability were analyzed. Linear relationships were found between the concentration and peak current, with good stability and limits of detection of 8 [micro sign]M for catechin, epigallocatechin gallate and epicatechin, and 14 [micro sign]M for epicatechin gallate. Optimum conditions were applied to the detection of selected catechins in a commercially available green tea extract nutraceutical and the results were compared to HPLC analysis. The analysis using microchip micellar electrokinetic chromatography and pulsed amperometric detection was completed in 4.5 min, 10 times faster than the HPLC analysis.

Effects of grape cell culture extracts on human topoisomerase II catalytic activity and characterization of active fractions

Grape and its cell culture extracts are rich in flavonoids and stilbenes that are biologically active. The objective of this study was to evaluate possible inhibitory effects of grape (a Vitis hybrid Bailey Alicant A) cell culture extract and subfractions on human DNA topoisomerase II catalytic activity and to characterize constituents in the most potent fractions. At 5 microg/mL, grape cell crude extract and Toyopearl (TP) fractions 2-6 provided significantly greater inhibition of topoisomerase II catalytic activity than quercetin, a chemopreventive agent previously known as a topoisomerase catalytic inhibitor. The most potent topoisomerase II catalytic inhibitors from grape cell culture extracts in descending order of potency were TP fractions 4 and 6 (IC(50) = 0.28-0.29 microg/mL), TP-3 (IC(50) = 0.74 microg/mL), and crude extract (IC(50) = 1.02 microg/mL); each was significantly more potent than resveratrol (IC(50) = 18.0 microg/mL), another well-known chemopreventive topoisomerase II catalytic inhibitor. Using both high-performance liquid chromatography and liquid chromatography electrospray ionization mass spectrometry, constituents in TP-4 and TP-6 were characterized. These constituents included cyanidin-3,5-diglucoside, malvidin-3-acetylglucoside, peonidin-3-coumaryl-5-diglucoside, procyanidin B(1), procyanidin B(2), procyanidin B(5), procyanidin dimer digallate, procyanidin C(1), myricetin, and rutin, none of which have been previously characterized from grape cell cultures. The significant potency especially of TP-4 and TP-6 from grape cell cultures suggests that these fractions may have potential as chemopreventive agents.

Alcohol and liver cancer

Hepatocellular carcinoma is the eighth most frequent cancer in the world, accounting for approximately 500,000 deaths per year. Unlike many malignancies, hepatocellular carcinoma occurs predominantly within the context of known risk factors, with hepatic cirrhosis being the most common precursor to the development of hepatocellular carcinoma. After ethanol ingestion, the liver represents the major site of metabolism. Ethanol metabolism by alcohol dehydrogenase leads to the generation of acetaldehyde and free radicals that bind rapidly to numerous cellular targets, including components of cell signaling pathways and DNA. In addition to direct DNA damage, acetaldehyde depletes glutathione, an antioxidant involved in detoxification. Chronic ethanol abuse leads to induction of hepatocyte microsomal cytochrome P450 2E1, an enzyme that metabolizes ethanol to acetaldehyde and, in doing so, causes further free radical production and aberrant cell function. Cytochrome P450 2E1-dependent ethanol metabolism is also associated with activation of procarcinogens, changes in cell cycle, nutritional deficiencies, and altered immune system responses. The identification of oxidative stress in mediating many deleterious effects of ethanol in the liver has led to renewed interest in the use of dietary antioxidants as therapeutic agents. Included in this group are S-adenosyl-L-methionine and plant-derived flavanoids.