Anti-genotoxic effects in mice after the interaction between coffee and dietary constituents

Caffeic acid, a dietary polyphenol, as a promising candidate for combination therapy

Increased effectiveness and decreasing toxicity are prime objectives in drug research. Overwhelming evidence suggests the use of appropriate combination therapy for the better efficacy of drugs owing to their synergistic profile. Dietary active constituents play a major role in health outcomes. Therefore, it is possible to increase the effectiveness of the drug by combining contemporary medication with active natural/semi-synthetic constituents. One such dietary constituent, caffeic acid (CA), is a by-product of the shikimate pathway in plants and is a polyphenol of hydroxycinnamic acid class. Extensive research on CA has proposed its efficacy against inflammatory, neurodegenerative, oncologic, and metabolic disorders. The synergistic/additive effects of CA in combination with drugs like caffeine, metformin, pioglitazone, and quercetin have been reported in several experimental models and thus the present review is an attempt to consolidate outcomes of this research. Multi-target-based mechanistic studies will facilitate the development of effective combination regimens of CA.

CHEMICAL CONSTITUENTS OF GEUM RIVALE L. AND THEIR BIOLOGICAL ACTIVITY

The aim of the study is to review the literature data on the chemical constituents of arial and underground parts of Geum rivale L. (Rosaceae) and the pharmacological activity of its extracts and individual compounds.

Materials and methods. The study was carried out using Internet resources (Google Scholar, PubMed) and library databases (e-Library, Scopus, Web of Science). The main research methods were a review and analysis of the literature data on the topic for the period from 1958 up to the present.

Results. For the period from 1958 up to the present more than 80 components in the arial and underground parts of G. rivale have been identified.  Among them there were components of the essential oil, phenolic acids and coumarins, aglycones of flavonoids, including luteolin, apigenin, quercetin and kaempferol, as well as a number of their glycosides and glucuronides, ellagitannins (hemin A, B, C, D, pedunculagin, stachiurin/casuarinin, tellimagrandin I). Some aspects of the pharmacological activity of total extracts and individual secondary metabolites of G. rivale have been studied, anti-inflammatory, antioxidant, antimicrobial, antiviral activities have been experimentally confirmed.

Conclusion. The analysis of the literature data showed that a further study of the composition of metabolites of G. rivale and their pharmacological activity is an urgent task, the solution of which will expand the range of use of this plant in medical practice and consider G. rivale as a promising source of pharmaceutical substances for the creation of new drugs and biologically active additives.

Comparative Susceptibility Study Against Pathogens Using Fermented Cranberry Juice and Antibiotics

In the present study, unfermented and fermented cranberry juice in combination with the Antibiotics vancomycin and tigecycline were tested for their antimicrobial activity. Cranberry juice was fermented with a recently isolated potentially probiotic Lactobacillus paracasei K5. The tested strains selected for this purpose were Enterococcus faecalis, E. faecium, Enterobacter cloacae and Staphylococcus aureus. The methods followed were the determination of zones inhibition, Minimum Inhibitory Concentration (MIC) and Fractional Inhibitory Concentration Index (FICI). Tigecycline together with fermented juice exhibited larger Zones of Inhibition (ZOI) in strains of E. faecium (65 ± 4.8 mm) compared to the respective ZOI with tigecycline and unfermented juice (no zone). The same outcome was also obtained with E. cloacae. Vancomycin together with fermented juice exhibited larger ZOI in strains of E. faecium (28 ± 2.2 mm) compared to the respective ZOI with vancomycin and unfermented juice (24 ± 2.3 mm). The lowest MIC values were recorded when tigecycline was combined with fermented cranberry juice against S. aureus strains, followed by the same combination of juice and antibiotic against E. cloacae strains. FICI revealed synergistic effects between fermented juice and tigecycline against a strain of E. faecium (A2020) and a strain of E. faecalis (A1940). Such effects were also observed in the case of fermented juice in combination with vancomycin against a strain of S. aureus (S18), as well as between fermented juice and tigecycline against E. cloacae (E1005 and E1007) strains. The results indicate that the antibacterial activity of juice fermented with the potentially probiotic L. paracasei K5 may be due to synergistic effects between some end fermentation products and the antibiotic agents examined.

Assessment of Cellular Mutagenicity of Americano Coffees from Popular Coffee Chains

Coffee is a popular beverage worldwide, but coffee beans can be contaminated with carcinogens. The Ames Salmonella mutagenicity test is often used for analysis of carcinogens for mutagenicity. However, previous studies have provided controversial data about the direct mutagenicity of coffee beans based on Ames test results. This study was conducted to determine the mutagenicity of popular Americano coffee based on results from the Ames test. Coffee samples without additives that were served by five international coffee chain restaurants were subjected to the analysis using Salmonella Typhimurium tester strains TA98, TA100, and TA1535. The levels of bacterial revertants in samples from coffee chains were lower than the twofold criterion of the control sets, and no significant dose-response effect was observed with or without rat liver enzyme activation. These data indicate that Americano coffees from the selected coffee chains possessed no direct mutagenic activity with or without enzyme activation. These findings suggest a low mutagenic risk from Americano coffees served by the selected coffee chains and support the use of other methods to confirm the nonmutagenicity of coffee products. These results are consistent with most recent epidemiological reports.

Polyphenols as possible bioprotectors against cytotoxicity and DNA damage induced by ochratoxin A

The present study aimed to investigate the protective effects of luteolin (L), chlorogenic acid (ChlA) and caffeic acid (CafA) against cyto-genotoxic effects caused by OTA. Vero cells and rat lymphocytes were used and viability was measured by neutral red uptake, MTT and trypan blue dye exclusion method. L (50 and 100μg/mL), ChlA (100 and 200μg/mL) and CafA (10-50μg/mL) reduced the damage induced by OTA (10μg/mL) on both cells type shown a good protective effect. The comet and micronucleus tests in Balb/c mice were performed. ChlA (10mg/kg bw) reduced OTA (0.85mg/kg bw)-induced DNA damage on blood and bone marrow cells, CafA (10mg/kg bw) showed protective effect only in blood cells and luteolin (2.5mg/kg bw) failed to protect DNA integrity on cells. In conclusion, polyphenols tested reduced the toxicity caused by OTA on different target cells with good protective effect, being ChlA the compound that showed the best effects.

Genotoxic, antigenotoxic and phytochemical assessment of Terminalia actinophylla ethanolic extract

Terminalia actinophylla has been used for anti-diarrheic and haemostatic purposes in Brazil. The fly spot data obtained after exposure of marker-heterozygous Drosophila melanogaster larvae to T. actinophylla ethanolic extract (TAE) in the standard (ST) and high bioactivation (HB) crosses revealed that TAE did not induce any statistically significant increment in any spot categories. Differences between the two crosses are related to cytochrome P450 (CYPs) levels. In this sense, our data pointed out the absence of TAE-direct and indirect mutagenic and recombinagenic action in the Somatic Mutation and Recombination Test (SMART). When the anti-genotoxicity of TAE was analyzed, neither mitomycin C (MMC) nor ethylmethanesulfonate (EMS) genotoxicity was modified by the post-exposure to TAE, which suggests that TAE has no effect on the mechanisms involved in the processing of the lesions induced by both genotoxins. In the mwh/flr(3) genotype, co-treatment with TAE may lead to a significant protection against the genotoxicity of MMC and a weak but significant effect in the toxic genetic action of EMS. The overall findings suggested that the favorable modulations by TAE could be, at least in part, due to its antioxidative potential.

Genoprotective effects of lignin isolated from oil palm black liquor waste

Black liquor waste (BLW), a major by-product of palm oil extraction process contains lignin as one of the constituents. Lignin isolated from BLW was evaluated for antioxidant and genoprotective properties and was compared with the commercial lignin for overall efficacy. Antioxidant compounds (phenolics and tannins) and antioxidant activities (phosphomolybdenum assay, ABTS(+) and FRAP assays) of lignin isolated from BLW were compared with commercial lignin. Bone marrow micronucleus (MN) test was employed for evaluating the dose-yield protective effect against cyclophosphamide (CP, 50mg/kg b.w.) induced genotoxicity in mouse. Results revealed isolated lignin to exhibit rich antioxidant activities. A decrease in MN frequency and recovery of P/N ratio (P: polychromatic erythrocytes, N: normochromatic erhythocytes) indicated protective effects of lignin against cyclophosphamide induced genotoxicity and cytotoxicity. The efficacy of BLW-derived lignin as an antioxidant and genoprotective agent was comparable to commercial lignin. Results on lignin isolated from BLW are envisaged to find potential applications in food and/or pharmaceutical industries.

The effects of coffee on enzymes involved in metabolism of the dietary carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in rats

The effects of coffee on the metabolism and genotoxicity of the dietary carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were investigated. Coffee diminished the bacterial mutagenicity of PhIP in the Ames reversion assay through inhibition of cytochrome P450 1A2 (CYP1A2), a key enzyme involved in the metabolic activation of PhIP. When given as part of the diet (0, 1 or 5% w/w) to male Fischer-344 rats for 2 weeks, coffee affected the expression of hepatic enzymes involved in PhIP metabolism. Coffee increased the expression of CYP1A2 by 16-fold in the 5% coffee-treated group, and approximately half of this inductive effect was attributed to caffeine. Coffee also increased the expression of enzymes involved in the detoxication of PhIP. A 2-fold increase in expression of glutathione S-transferase alpha was observed, UDP-glucuronosyl transferase (UGTs) activities of p-nitrophenol increased 2-fold, while N(2)-and N3-glucuronidation of the genotoxic metabolite 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (HONH-PhIP) increased by 1.3-fold in the 5% coffee-treated over the control group. The amount of PhIP (0.75 mg/kg, 24 h) eliminated in urine as the N(2)-and N3-glucuronide conjugates of HONH-PhIP increased by 1.8- and 2.5-fold, respectively, in the 5% coffee-treated group over control rats, suggesting either increased rates of N-oxidation of PhIP or N-glucuronidation of HONH-PhIP. Despite the strong induction of CYP1A2, there was no increase in PhIP-DNA adduct formation in colon and pancreas while liver adducts decreased by 50% over control animals. These data suggest that the effect of coffee on inhibition of PhIP N-oxidation and ensuing DNA damage is more important in vivo than its effect on induction of PhIP N-hydroxylation.

Dicinnamoylquinides in roasted coffee inhibit the human adenosine transporter

Preliminary screening of a minor, non-xanthine constituent of roasted coffee, 3,4-diferuloyl-1,5-quinolactone (DIFEQ), showed inhibition of the adenosine transporter at low micromolar concentration. DIFEQ is a neutral derivative of the chlorogenic acids, i.e. isomeric mono- and di-substituted coumaroyl-, caffeoyl-, and feruloyl-esters of quinic acid, formed in the roasting process of coffee. Displacement of the adenosine transporter antagonist [(3)H](S)-(nitrobenzyl)-6-thioinosine binding by DIFEQ in cultured U-937 cell preparations, expressing the human adenosine transporter protein (hENT1), showed a K(i) of 0.96+/-0.13 microM. Extracts of regular and decaffeinated coffee showed binding activities equivalent to 30-40 mg DIFEQ per three cups of coffee. Acute administration of a high dose of DIFEQ (100 mg/kg i.p.) reduced open field locomotion in mice for 20 min in correlation with brain levels of DIFEQ. Both 3,4-dicaffeoyl-1,5-quinide and 3,4-dicoumaroyl-1,5-quinide, two close structural analogs of DIFEQ also present in roasted coffee, showed similar affinities for the adenosine transporter, while the corresponding 3- and 4-mono caffeoyl- and feruloyl-quinides were one to two orders of magnitudes less active. This suggests that 3,4-dicinnamoyl-1,5-quinides in coffee could have the potential to raise extra-cellular adenosine levels, thereby counteracting the stimulant effect of caffeine.

The FEMA GRAS assessment of trans-anethole used as a flavouring substance. Flavour and Extract Manufacturer's Association

This publication is the fourth in a series of safety evaluations performed by the Expert Panel of the Flavour and Extract Manufacturers' Association (FEMA). In 1993, the Panel initiated a comprehensive program to re-evaluate the safety of more than 1700 GRAS flavouring substances under conditions of intended use. In this review, scientific data relevant to the safety evaluation of trans-anethole (i.e. 4-methoxypropenylbenzene) as a flavouring substance is critically evaluated by the FEMA Expert Panel. The evaluation uses a mechanism-based approach in which production of the hepatotoxic metabolite anethole epoxide (AE) is used to interpret the pathological changes observed in different species and sexes of laboratory rodents in chronic and subchronic dietary studies. Female Sprague Dawley rats metabolize more trans-anethole to AE than mice or humans and, therefore, are the most conservative model for evaluating the potential for AE-induced hepatotoxicity in humans exposed to trans-anethole from use as a flavouring substance. At low levels of exposure, trans-anethole is efficiently detoxicated in rodents and humans primarily by O-demethylation and omega-oxidation, respectively, while epoxidation is only a minor pathway. At high dose levels in rats, particularly females, a metabolic shift occurs resulting in increased epoxidation and formation of AE. Lower activity of the "fast" acting detoxication enzyme epoxide hydrolase in the female is associated with more pronounced hepatotoxicity compared to that in the male. The continuous intake of high dose levels of trans-anethole (i.e. cumulative exposure) has been shown in dietary studies to induce a continuum of cytotoxicity, cell necrosis and cell proliferation. In chronic dietary studies in rats, hepatotoxicity was observed when the estimated daily hepatic production of AE exceeded 30 mg AE/kg body weight. In female rats, chronic hepatotoxicity and a low incidence of liver tumours were reported at a dietary intake of 550 mg trans-anethole/kg body weight/day. Under these conditions, daily hepatic production of AE exceeded 120 mg/kg body weight. Additionally, neither trans-anethole nor AE show any evidence of genotoxicity. Therefore, the weight of evidence supports the conclusion that hepatocarcinogenic effects in the female rat occur via a non-genotoxic mechanism and are secondary to hepatotoxicity caused by continuous exposure to high hepatocellular concentrations of AE. trans-Anethole was reaffirmed as GRAS (GRASr) based on (1) its low level of flavour intake (54 microg/kg body weight/day); (2) its metabolic detoxication pathway in humans at levels of exposure from use as a flavouring substance; (3) the lack of mutagenic or genotoxic potential; (4) the NOAEL of 120 mg trans-anethole/kg body weight/day in the female rat reported in a 2 + -year study which produces a level of AE (i.e. 22 mg AE/kg body weight/day) at least 10,000 times the level (0.002 mg AE/kg body weight day) produced from the intake of trans-anethole from use as a flavouring substance; and (5) the conclusion that a slight increase in the incidence of hepatocellular tumours in the high dose group (550 mg trans-anethole/kg body weight/day) of female rats was the only significant neoplastic finding in a 2+ -year dietary study. This finding is concluded to be secondary to hepatotoxicity induced by high hepatocellular concentrations of AE generated under conditions of the study. Because trans-anethole undergoes efficient metabolic detoxication in humans at low levels of exposure, the neoplastic effects in rats associated with dose-dependent hepatotoxicity are not indicative of any significant risk to human health from the use of trans-anethole as a flavouring substance.

Antimutagenic activity of carotenoids in green peppers against some nitroarenes

In Mexico, as well as in Central and South American countries, the consumption of peppers (Capsicum annuum) has been tradition for thousands of years; the per capita dietary intake of peppers is about 40 g/day. Peppers are an important source of beta-carotene and vitamin A, which have antimutagenic and/or anticarcinogenic properties. In the present study, Salmonella typhimurium tester strain YG1024 in the plate-incorporation test was used to examine the antimutagenicity of carotenois extracted from five different types of Capsicum spp. ('Chilaca', 'Poblano', 'Serrano', 'Jalapeño' and 'Pimiento') which were chosen, based on their consumption and availability on the local market. Extracts from these peppers were tested against 1-6-dinitropyrene (1,6-DNP) and 1,8-dinitropyrene (1,8-DNP) mutagenicity. Dose-response mutagenicity curves of 1-NP; 1,6-DNP and 1,8-DNP were obtained. For the antimutagenicity studies, doses of 0.05 microgram/plate, 0.20 ng/plate and 0.06 ng/plate for 1-NP, 1,6-DPN and 1,8-DNP respectively were chosen, and the number of net revertants/plate were 1008 for 1-NP, 512 for 1,6-DNP, and 712 for 1,8-DPN. Trans-beta-carotene and the extracts were not toxic to the bacteria at the concentrations tested. The extracts obtained from the peppers showed more inhibition than pure trans-beta-carotene on 1-NP; 1,6-DNP and 1,8-DNP mutagenicity. Chilaca pepper extract required 0.36 g (34 nmol expressed as trans-beta-carotene equivalents) of fresh pepper to inhibit 94% on 1-NP mutagenicity, 78% on 1,6-DNP mutagenicity and 84% on 1,8-DNP mutagenicity. Bell pepper ('Pimiento') extract required 1.53 g (50 nmol expressed as trans-beta-carotene) to obtain 87%, 79% and 73% inhibition on 1-NP; 1,6-DNP and 1,8-DNP mutagenicity respectively. Since pure beta-carotene inhibited only approximately 50% the mutagenicity of nitroarenes, these results suggest that each one of the pepper extracts have more than one antimutagenic compound (e.g., beta-carotene and xanthophylls) and those functional nutrients apparently have a synergistic effect.

Modulation of metal-induced genotoxicity by Maillard reaction products isolated from coffee

PM2 bacteriophage DNA was exposed to non-dialysable Maillard reaction products (MRPs) isolated from brewed (Br), boiled (Bo) and instant (I) coffee brew extracts in a Fe2+ catalysed Fenton reaction at four pH conditions (i.e. 7.5, 4.0, 3.2, 2.6). MRPs were incubated with DNA either directly with Fe2+, or following a short preincubation period conducted with Fe2+ in an atmosphere of oxygen or argon. Damage to supercoiled DNA resulting in strand scissions as characterized by both nicked circular and linear forms were found to occur either with coffee MRPs or Fe2+ alone, in a dose-dependent manner at all pH conditions tested. At low MRP concentrations, damage to DNA with respect to Fe2+ was lowered only when MRPs were preincubated with Fe2+ in argon or oxygen before incubating with DNA. The addition of MRPs and Fe2+ to DNA without preincubation, had no effects in protecting DNA damage. This finding showed that a preincubation step is necessary for MRPs to chelate Fe2+ in order to mitigate the Fenton reaction. In contrast, the protective effects against Fe2+-induced DNA breakage by MRPs were lost at high coffee MRP concentrations, irrespective of the incubation method used. Increasingly higher concentrations of MRPs in combination with Fe2+ actually enhanced the breakage of DNA with respect to the control. These results indicate that MRPs at high concentrations do not improve Fe2+ ion chelation, but rather accelerate the DNA breakage by possibly changing the redox state of the transition element.

In vivo antigenotoxic effects of dietary agents and beverages co-administered with urethane: assessment of the role of glutathione S-transferase activity

Antigenotoxic effects and changes in glutathione S-transferase (GST) activity were assessed in mice after oral co-administration of urethane (URE) with aqueous extracts of dietary vegetables (carrot, spinach and cabbage), spices (cinnamon, pepper, cumin, clove and cardamom), tea and coffee. The results of the genotoxicity assay (micronucleus test) demonstrated dose-related antigenotoxic effects after URE was co-administered with aqueous extracts of vegetables, spices, tea and coffee. Inhibition of GST activity was observed 4 h after treatment with URE alone. Co-administration of URE with extracts of vegetables, coffee and spices resulted in dose-related attenuation of the inhibitory effect of URE on GST activity. However, tea had no effect on inhibition of GST activity by URE. Hence an association between antigenotoxicity and GST activity could not be established.