Utilization of gallic acid to inhibit some toxic activities caused by Bothrops jararaca or B. jararacussu snake venoms

Snake bite envenoming is a serious public health issue, affecting thousands of people worldwide every year, especially in rural communities of tropical and subtropical countries. Injection of venom into victims may cause hemorrhaging, blood coagulation imbalance, inflammation, pain, edema, muscle necrosis, and eventually, death. The official validated treatment recommended by governments is the administration of antivenom that efficiently prevents morbidity and mortality. However, this therapy does not effectively neutralize the local effects of Viperidae venoms which constitute one of the leading causes of disability or amputation of the affected limb. Thus, bioprospecting studies seeking for alternative therapies to complement antivenom should be encouraged, especially those investigating the blockage of local venomic toxicity. Plants produce a great diversity of metabolites with a wide range of pharmacological and biological properties. Therefore, the objective of this study was to assess the utilization of gallic acid, which is widely found in plants, against some toxic in vitro (coagulation, proteolytic, and hemolytic) or in vivo (edematogenic, hemorrhagic, and lethal) activities of Bothrops jararaca or B. jararacussu venom. Gallic acid was incubated with B. jararaca or B. jararacussu venom (incubation protocol), after which, in vitro or in vivo assays were performed. Additionally, a gel containing gallic acid was developed and topically applied over the skin of mice after injection of B. jararaca or B. jararacussu venom (treatment protocol), and then, a hemorrhagic assay was carried out. As a result, gallic acid inhibited the toxic activities, with variable efficacy, and the gallic acid gel neutralized B. jararaca or B. jararacussu venom-induced hemorrhagic activity. Gallic acid was devoid of in vitro toxicity as shown through a hemocompatibility test. Thus, these findings demonstrate the potential of gallic acid in the development of an alternative agent to treat victims of snake bites inflicted by Bothrops species.

Toxicological implications of amplifying the antibacterial activity of gallic acid by immobilisation on silica particles: A study on C. elegans

Immobilisation of natural compounds on solid supports to amplify antimicrobial properties has reported successful results, but modifications to physico-chemical properties can also imply modifications from a toxicological viewpoint. This work aimed to study the immobilising process of gallic acid in the antibacterial activity of L. innocua and its toxicological properties in vivo using Caenorhabditis elegans. The experiment was based on obtaining the minimum bactericidal concentration for free and immobilised gallic acid by comparing lethality, locomotion behaviour, chemotaxis and thermal stress resistance on C.elegans at those concentrations. The results showed a lowering minimum bactericidal concentration and modifications to nematode responses. Increased lethality and velocity of movements was observed. Immobilisation increased the repellent effect of gallic acid with a negative chemotaxis index. Thermal stress resistance was also affected, with higher mortality for immobilised gallic acid compared to bare particles and free gallic acid. Thus despite evidencing a generalised increase in the toxicity of gallic acid in vivo, lowering the minimum bactericidal concentration allowed a bacterial reduction of 99 % with less than one third of mortality for the nematodes exposed to free gallic acid.

Are Supplements Safe? Effects of Gallic and Ferulic Acids on In Vitro Cell Models

Polyphenols display health-promoting properties linked to their biological activities. They are initially absorbed in the small intestine, then they are largely metabolized in the colon, whereupon they are able to exert systemic effects. The health-promoting properties of polyphenols have led to the development of food supplements, which are also largely consumed by healthy people, even if data on their safety are still yet lacking. In the present paper, the content of gallic acid and ferulic acid was analyzed in two supplements, and shown to be higher than the relative contents found in fruit and flour. To evaluate the effects of these phenolic compounds on epithelial intestinal tissue, gallic and ferulic acids were added to a new in vitro model of the intestinal wall at different concentrations. The effects on viability, proliferation and migration of these compounds were respectively tested on three different cell lines (Caco2, L929 and U937), as well as on a tridimensional intestinal model, composed of a mucosal layer and a submucosa with fibroblasts and monocytes. Results indicated that gallic and ferulic acids can exert toxic effects on in vitro cell models at high concentrations, suggesting that an excessive and uncontrolled consumption of polyphenols may induce negative effects on the intestinal wall.

The toxic effect of gallic acid on biochemical factors, viability and proliferation of rat bone marrow mesenchymal stem cells was compensated by boric acid

OBJECTIVE

Gallic acid (GA) and boron are found in many plants. Our previous studies showed 6 ng/ml boric acid (BA) had positive effect on biochemistry of rat bone marrow mesenchymal stem cells (MSCs) and their osteogenic differentiation. Therefore, we investigate the effect of different doses of GA alone and in the presence of BA on MSCs.

MATERIALS AND METHODS

the viability of MSCs was assayed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and trypan blue at 12, 24 and 36 h in presence of different concentration of GA. Then 30 and 120 μM of GA as well as 6 ng/ml of BA in 36 h were selected for further study. The proliferation, Morphology, sodium and potassium level, concentration of calcium, activity of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) as well as malondialdehyde (MDA) concentration, total antioxidant capacity (FRAP) and activity of superoxide dismutase (SOD) and catalase (CAT) were estimated.

RESULT

Results showed GA alone reduced viability, proliferation, nuclear diameter and cytoplasm area. In addition, GA showed anaerobic metabolic shift but no change in MDA and scavenging enzymes. Both concentration of GA caused elevation of FRAP, whereas only at 120 μM increased the sodium-potassium and reduced calcium. The co-treatment of GA and BA improves the viability, proliferation and morphology of the cells. In addition, co-treatment compensated the metabolic shift caused by GA and could balance the potassium level and FRAP as it was raised by GA.

CONCLUSION

Although GA content of tea is harmful to the cells but simultaneous consumption of fruits and vegetables as a rich source of boron might compensate the damaging effect of GA.

Identification of Ellagic Acid from Plant Rhodiola rosea L. as an Anti-Ebola Virus Entry Inhibitor

The recent 2014-2016 West African Ebola virus epidemic underscores the need for the development of novel anti-Ebola therapeutics, due to the high mortality rates of Ebola virus infections and the lack of FDA-approved vaccine or therapy that is available for the prevention and treatment. Traditional Chinese medicines (TCMs) represent a huge reservoir of bioactive chemicals and many TCMs have been shown to have antiviral activities. 373 extracts from 128 TCMs were evaluated using a high throughput assay to screen for inhibitors of Ebola virus cell entry. Extract of Rhodiola rosea displayed specific and potent inhibition against cell entry of both Ebola virus and Marburg virus. In addition, twenty commercial compounds that were isolated from Rhodiola rosea were evaluated using the pseudotyped Ebola virus entry assay, and it was found that ellagic acid and gallic acid, which are two structurally related compounds, are the most effective ones. The activity of the extract and the two pure compounds were validated using infectious Ebola virus. The time-of-addition experiments suggest that, mechanistically, the Rhodiola rosea extract and the effective compounds act at an early step in the infection cycle following initial cell attachment, but prior to viral/cell membrane fusion. Our findings provide evidence that Rhodiola rosea has potent anti-filovirus properties that may be developed as a novel anti-Ebola treatment.

Influence of waterborne gallic and pelargonic acid exposures on biochemical and reproductive parameters in the zebrafish (Danio rerio)

Gallic and pelargonic acids are biologically derived substances receiving a growing interest as eco-friendly biocides with potential applications in freshwater system management. However, some data gaps remain to address their chronic ecotoxicity issue, particularly for fish. This work aimed at investigating the sublethal effects of a long-term waterborne exposure of zebrafish to these compounds. Mature fish were exposed to gallic or pelargonic acid at the concentrations of 0, 0.05, 0.5 and 5 mg/L during one month under semi-static conditions. Fecundity, hatching rate and median hatching time were regularly evaluated. Circulating sex hormone levels (11 ketotestosterone -11 KT, 17 βestradiol -E2-), plasma vitellogenin (Vtg), and gonad histology were monitored in males and females after exposure. Lactate dehydrogenase (LDH), total glutathione peroxydase (GPx) and glutathione-S transferase (GST) activities were assessed as enzymatic biomarkers of exposure in fish liver. Significant increases of GPx activity were reported in females exposed to both type of chemicals regardless the contamination level. Moreover, 5 mg/L gallic acid induced a decrease in 11-KT levels for males. For fish exposed to pelargonic acid, decreases in circulating hormone levels were reported respectively at 0.05 and 5 mg/L for 11-KT in males, and at 0.5 mg/L for E2 in females. However, no histological alteration in gonads neither significant variation in reproductive performances were detected following zebrafish exposure to gallic or pelargonic acid. Additional investigations concerning the mode of application and the environmental fate of these substances may warrant their further use in freshwater systems at concentrations compatible with biocidal/allelochemical effects. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 227-240, 2017.

Layered Double Hydroxide as a Vehicle to Increase Toxicity of Gallate Ions against Adenocarcinoma Cells

The antineoplasic activity of gallic acid has been reported. This compound induces apoptosis and inhibits the growth of several neoplasic cells. However, this molecule is easily oxidized and degraded in the body. The aim of this work was to intercalate gallate ions into layered double hydroxide (LDH) nanoparticles under controlled conditions to reduce oxidation of gallate and to evaluate its toxicity against the A549 adenocarcinoma cell line. An isopropanol medium under nitrogen atmosphere was adequate to intercalate gallate ions with a lesser oxidation degree as detected by electron spin resonance spectroscopy. Concentrations of the hybrid LDH-gallate nanoparticles between 0.39 and 25 µg/mL reduced the cell viability to 67%, while the value reached with the pure gallic acid and LDH was 90% and 78%, respectively, thus proving that the combination of gallate ions with the inorganic nanoparticles increases the toxicity potential within this dose range.

Allelopathic potential and ecotoxicity evaluation of gallic and nonanoic acids to prevent cyanobacterial growth in lentic systems: A preliminary mesocosm study

The increase in anthropogenic nutrient loading affecting many freshwater ecosystems combined with global warming may lead to cyanobacterial blooms on an increasingly frequent basis. Among the various physicochemical and biological methods which have been proposed to rapidly control blue-green algae growth, the use of plant-derived substances such as allelochemicals has gained great interest as an environment-friendly approach. The primary aim of this work was to evaluate the efficiency of gallic and nonanoic acid application to preemptively inhibit cyanobacterial growth in lentic hydrosystems. In order to address the process feasibility under realistic exposure scenarios, thirteen outdoor freshwater mesocosms (unit volume: 3m(3)) were designed, each containing phytoplankton (including local blue-green algae species) and various non-target organisms from higher trophic levels (Physa, Lymnaea, Gammarus, and Scardinius erythrophthalmus). After an 8-week mesocosm stabilization period, a full factorial design based on the presence/absence of gallic acid (GA) and nonanoic acid (NA) (including a control group) was implemented into the exposure tanks. Regular monitoring of major phytoplankton taxa was conducted during a 28-day experiment using an on-line fluorometer. The main results suggested that gallic acid was more efficient than nonanoic acid at limiting cyanobacterial growth at concentrations as low as 1 mg L(-1). Successive gallic acid applications (at 1, 2 and 4 mg L(-1)) at the early stages of cyanobacterial growth did not allow the complete elimination of blue-green algae from the mesocosms. However, the specificity of the allelopathic effect of gallic acid towards cyanobacteria was compatible with the maintenance of a primary productivity in the treated tanks as indicated by the photoautotrophic growth of other algal taxa. Finally, no biomarker induction signal could be reported in non-target species. Further gallic acid application trials in lentic systems such as small freshwater ponds may help to design innovative allelopathy-based aquatic ecotechnologies.

Acute toxicity and sublethal effects of gallic and pelargonic acids on the zebrafish Danio rerio

Gallic and pelargonic acids are naturally found in a variety of plants and food products. Despite their extensive use in man-made applications, little is known regarding their potential risks to aquatic vertebrates. The aim of this work was to assess the acute toxicity of these polyphenolic and fatty acid compounds to the zebrafish. In order to get insights into sublethal effects, the enzyme activity of usual biomarkers related to oxidative stress and biotransformation were also assessed in fish. These latter included total superoxide dismutase, catalase as well as total glutathione peroxidase for antioxidant defence mechanisms and glutathione S-transferase for biotransformation related enzyme. Gallic acid was practically non-toxic (96-h lethal concentration (LC50) > 100 mg/L) whereas pelargonic acid was slightly toxic (96-h LC50 of 81.2 mg/L). Moreover, biomarker analyses indicated enhanced superoxide dismutase activity in fish exposed to 20, 40 and 100 mg/L of gallic acid compared to control. A dose-dependent induction of glutathione peroxidase and glutathione S-transferase was reported following gallic acid exposure at the tested concentrations of 10, 20 and 40 mg/L, with the exception of 100 mg/L of substance where basal activity levels were reported. In the case of pelargonic acid, there was no change in antioxidant enzyme activity while an inhibition of glutathione S-transferase was observed from organisms exposed to 45, 58 and 76 mg/L of test solution. The results concerning sublethal effects on biological parameters of zebrafish highlighted thereby the need for further investigations following chronic exposure to both organic acids.

Antiviral activity of theaflavin digallate against herpes simplex virus type 1

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Black tea theaflavins show significant anti-herpes simplex virus type 1 (HSV-1) effect on both A549 and Vero cells.

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Theaflavin is able to inhibit the entry of HSV-1 to its host by blocking the adsorption and penetration processes.

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Application of these agents as natural topical remedy to prevent and treat HSV-1 infection and spreading is promising.

Tea is the second most consumed drink in the world. The beneficial effects of tea have been mostly attributed to its catechin content. Black tea is derived from the leaves of Camellia sinensis plant, and it is rich in theaflavin polyphenols, in particular theaflavin (TF1), theaflavin-3-monogallate (TF2A), theaflavin-3′-monogallate (TF2B), and theaflavin-3,3′-digallate (TF3). Vero and A549 cells were used to evaluate the effect of purified individual black tea theaflavins as anti-herpes simplex virus 1 agents. With the rise of HSV resistant strains, there is a critical need to develop novel antiherpesviral treatments. Results of the cytotoxicity assay tested by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium] showed that TF1, TF2, and TF3 are not toxic to Vero and A549 cells at a concentration up to 75 μM. The antiviral activity of the individual theaflavins was tested by plaque reduction assay, MTS assay, flow cytometric analysis and confocal microscopy observations. The results showed that TF1, TF2, and TF3 exhibit potent, dose-dependent anti-HSV-1 effect, with TF3 being the most efficient in both Vero and A549 cells. A concentration of 50 μM TF3 and above was sufficient to inhibit >99% of the production of HSV-1 viral particles. The anti-HSV-1 effect of TF3 is due to a direct effect on the virions, and treating Vero or A549 cells with TF3 for 1 h prior to infection, or treating the cells at different times post infection does not inhibit HSV-1 production. TF3 is stable at vaginal pH, indicating its potential to be a promising natural and affordable remedy against herpes simplex viral infections.

In vitro protection of biological macromolecules against oxidative stress and in vivo toxicity evaluation of Acacia nilotica (L.) and ethyl gallate in rats

BACKGROUND

Recently, enormous research has been focused on natural bioactive compounds possessing potential antioxidant and anticancer properties using cell lines and animal models. Acacia nilotica (L.) is widely distributed in Asia, Africa, Australia and Kenya. The plant is traditionally used to treat mouth, ear and bone cancer. However, reports on Acacia nilotica (L.) Wild. Ex. Delile subsp. indica (Benth.) Brenan regarding its toxicity profile is limited. Hence in this study, we investigated the antioxidant capacity and acute toxicity of ethyl gallate, a phenolic antioxidant present in the A. nilotica (L.) leaf extract.

METHODS

The antioxidant activity of ethyl gallate against Fenton's system (Fe3+/H2O2/ascorbic acid) generated oxidative damage to pBR322 DNA and BSA was investigated. We also studied the interaction of ethyl gallate to CT-DNA by wave scan and FTIR analysis. The amount of ethyl gallate present in the A. nilotica (L.) leaf extract was calculated using HPLC and represented in gram equivalence of ethyl gallate. The acute toxicity profile of ethyl gallate in the A. nilotica (L.) leaf extract was analyzed in albino Wistar rats. Measurement of liver and kidney function markers, total proteins and glucose were determined in the serum. Statistical analysis was done using statistical package for social sciences (SPSS) tool version 16.0.

RESULTS

Ethyl gallate was found to be effective at 100 μg/mL concentration by inhibiting the free radical mediated damage to BSA and pBR322 DNA. We also found that the interaction of ethyl gallate and A. nilotica (L.) leaf extract to CT-DNA occurs through intercalation. One gram of A. nilotica (L.) leaf extract was found to be equivalent to 20 mg of ethyl gallate through HPLC analysis. Based on the acute toxicity results, A. nilotica (L.) leaf extract and ethyl gallate as well was found to be non-toxic and safe.

CONCLUSIONS

Results revealed no mortality or abnormal biochemical changes in vivo and the protective effect of A. nilotica (L.) leaf extract and ethyl gallate on DNA and protein against oxidative stress in vitro. Hence, A. nilotica (L.) leaf extract or ethyl gallate could be used as potential antioxidants with safe therapeutic application in cancer chemotherapy.

Toxicity of aqueous C70-gallic acid suspension in Daphnia magna

The present study assessed the toxic effects of stable aqueous colloidal suspensions of gallic-acid-stabilized C(70) fullerene on Daphnia magna. The suspensions were stabilized through noncovalent surface modification with gallic acid. In addition to whole-organism responses, changes in antioxidative processes in D. magna were quantified. Acute toxicity was observed with 96LC50 for C(70) -gallic acid of 0.4 ± 0.1 mg/L C(70) . Daphnia magna fecundity was significantly reduced in 21-d bioassays at C(70) -gallic aqcid concentrations below quantifiable limits. Antioxidant enzyme activities of glutathione peroxidase and superoxide dismutase as well as lipid peroxidation suggested that exposed organisms experienced oxidative stress. Microscopic techniques used to determine cellular toxicity via apoptosis proved unsuccessful.

In vitro and in vivo skin anti-aging evaluation of gel containing niosomes loaded with a semi-purified fraction containing gallic acid from Terminalia chebula galls

CONTEXT

The galls of Terminalia chebula Retz. (Combretaceae) frequently appear in many Thai Lanna medicinal plant recipes for promotion of longevity.

OBJECTIVE

The objective of this study was to evaluate the skin anti-aging of gel containing niosomes loaded with a semi-purified fraction containing gallic acid from T. chebula galls.

METHOD

The semi-purified fraction containing phenolic compounds including gallic acid isolated from T. chebula galls loaded in non-elastic or elastic niosomes, and its developed gel, were evaluated for rabbit skin irritation by the closed patch test and skin anti-aging in human volunteers by measuring skin elasticity and roughness.

RESULTS

Gel containing the fraction unloaded (SS) or loaded in non-elastic (SN) or elastic (SE) niosomes and gallic acid loaded in non-elastic (GN) or elastic (GE) niosomes showed no skin irritation, whereas the unloaded gallic acid (GS) gave the irritation in rabbit's skin by the closed patch test. The % parameter changes of skin elastic recovery and skin elastic extension when applied with SN and SE gels were +28.73 and +32.57; -21.25 and -22.63%, respectively. SN and SE gel also showed a significant decrease of the maximum and average roughness values with the parameter changes of -29.43 and -32.38; -39.47 and -35.28%, respectively.

CONCLUSION

The semi-purified fraction loaded in niosomes indicated not only higher chemical stability of gallic acid containing in the fraction, but also more in vivo anti-aging activities than the unloaded fraction when incorporated in gel.

[Chemical constituents from the roots of Pithecellobium lucidum and their cytotoxic activity]

Six compounds were isolated from the roots of Pithecellobium lucidum by various chromatograhic techniques such as column chromatography on silica gel and Sephadex LH-20, and preparative HPLC, and their structures were elucidated as julibroside A2 (1), 3-[ (2-acetamido-2-deoxy-beta-D-glucopyranosyl) oxy] -16alpha-hydroxyolean-12-en-28-oic acid (2), galloyl acid (3), ethyl gallate (4), (+)-catechin (5), (-)-gallocatechin gallate (6) on the basis of spectrascopic data analysis. Compounds 1-6 were isolated from Pithecellobium lucidum for the first time. Compound 2 showed selective cytoxic activity against the human cell lines A2780 with an IC50 value of 1.72 micromol x L(-1).

Biodegradability of kraft mill TCF biobleaching effluents: application of enzymatic laccase-mediator system

The great amount of pollutants released from kraft pulp processes, mainly from cooking and bleaching stages, is one of the most relevant environmental problems in this type of industry. New bleaching sequences are being studied based on the use of oxidative enzymes from fungal cultures. In this study, the bleaching systems consisting of Laccase and different mediators such as 1-hydroxybenzotriazole, violuric acid, syringaldehyde and methyl syringate in the bleaching sequence of Eucalyptus globulus kraft pulp were applied. The main objective of this study is to evaluate the aerobic and anaerobic biodegradability and toxicity to Vibrium fischeri of generated L-stage and total bleaching sequence effluents. The highest levels of aerobic and anaerobic degradation of the generated effluents were achieved for treatments with laccase plus violuric acid, with 80% of aerobic degradation and 68% of anaerobic biodegradation. V. fischeri toxicity was remarkably reduced for all the effluents after aerobic degradation.

Oral dose-ranging developmental toxicity study of an herbal supplement (NT) and gallic acid in rats

OBJECTIVE

To evaluate the combination of rhubarb, astragalus, red sage, ginger, and turmeric (mixture referred to as "NT") together with gallic acid for evidence of reproductive toxicity in rats.

METHODS

Fifty virgin female rats were cohabited with male rats. Day 0 of potential pregnancy was evidence of spermatozoa on vaginal smear. The presumably pregnant rats were randomized to five groups of 10 individuals and were fed by daily gavage on days 6-20 of presumed gestation with one of the following: deionized water placebo, 21.6 mg/kg per day, 215 mg/kg per day, 430 mg/kg per day, or 860 mg/kg per day of a mixture of NT (20%) and gallic acid (80%). Cesarean section was performed on day 21.

RESULTS

All 50 rats had one or more live fetuses and survived until they were killed. Body weight was reduced in the 860 mg/kg per day group compared with placebo: mean (SD), 406.8 (23.0) vs. 430.1 (27.7) g, P<0.05. There were no dose-related adverse events or differences between groups in uterine size, food intake, corpora lutea, implantations, litter size, number of live fetuses, and gender distribution of fetuses or fetal resorptions. There were no dead fetuses, and all placentae appeared normal. All rats and tissues were normal at necropsy. Fetal weights did not differ between groups, and there were no fetal abnormalities.

CONCLUSION

The combination of NT and gallic acid gave no evidence of reproductive toxicity at 430 mg/kg per day or below, which is reassuring should this combination be used in the future as a dietary herbal supplement for the treatment of obesity.

[Dynamic change of phenolic acids in soils around rhizosphere of replanted Rehmannia glutinosa]

OBJECTIVE

To determine 5 phenolic acids in the soils around rhizosphere of Rehmannia glutinosa in the field under normal rotation and successive cropping.

METHOD

Phenolic acids related to allelopathy effect in the soils around rhizosphere of R. glutinosa were determined by HPLC.

RESULT

The growth of R. glutinosa under normal rotation was strong. During harvest, the dry weight of the root tube and the volume of the R. glutinosa under normal rotation were 6.02 and 7.71 times of the ones under successive cropping.

CONCLUSION

The seeding stage and elongating stage are the crucial periods for the autotoxic effect of the R. glutinosa under continuous cropping. During these periods, the content of coumaric acid, 4-hydroxybenzoic acid, syringic acid, and ferulic acid of R. glutinosa under successive cropping are notably negative correlation with the growth of the leaf and root tuber of R. glutinosa under successive cropping. Among them, ferulic acid plays a major role in the restriction effect on R. glutinosa under successive cropping.

Performance of a fungal based SBR under pH extreme and shock phenolic exposure

An investigation was performed to explore the capabilities of a filamentous fungal biomass to grow non-aseptically in a glucose-fed Sequencing Batch Reactor system in very extreme environment (pH 3.5) conditions. Trichoderma viride Pers: Fr. Isolate 8/90 was used as inoculum. Microscopic investigations were carried out to confirm fungal dominance in the open culture. In batch tests, the fungal biomass showed a significant ability to grow and remove the applied organic load (2000 mg(Glucose) L(-1) d(-1)), with high biomass yields. Furthermore, the biomass showed an ability to resist gallic acid toxicity at high concentraions (1 g L(-1)) without any pre- exposure acclimation of the biomass. The biomass (about 2.5 g(VSS) L(-1)) demonstrated significant aerobic removal of gallic acid in a timeframe of 20 h from initial exposure. The robust characteristics of this SBR system demonstrate potential for future development of fungal based treatment for recalcitrant feedstocks or operation under extreme environmental conditions.

Assessment of the genotoxicity of olive mill waste water (OMWW) with the Vicia faba micronucleus test

The present study concerns the genotoxicity of olive mill waste water (OMWW) generated in mills producing olive oil in Morocco. The Vicia faba micronucleus test was used to evaluate the genotoxicity of OMWW and the six major phenolic compounds identified by HPLC in this effluent. Five dilutions of OMWW were tested: 0.1, 1, 5, 10 and 20%. Maleic hydrazide was used as a positive control. The results showed that OMWW was genotoxic at 10% dilution. In order to investigate the components involved in this genotoxicity, the six major phenols present in this effluent, oleuropein, gallic acid, 4-hydroxyphenyl acetic acid, caffeic acid, paracoumaric acid and veratric acid, were studied at concentrations corresponding to the genotoxic concentration of the OMWW itself. Two phenols, gallic acid and oleuropein induced a significant increase in micronucleus frequency in Vicia faba; the four other phenols had no significant genotoxic effect. These results suggest that under the experimental conditions of our assay, OMWW genotoxicity was associated with gallic acid and oleuropein.

Response of digestive gland cells of freshwater mussel Unio tumidus to phenolic compound exposure in vivo

The exposure of freshwater mussels Unio tumidus to phenolic compounds (tannic, ellagic and gallic acid) in vivo caused changes in proteins and DNA function of digestive gland cells. The mussels were exposed to various concentrations of tested polyphenols (60, 200 and 500 microM) for 24 and 48 h and their antioxidant and pro-oxidant effects were determined. The number of SH-groups was quantified spectrophotometrically using Ellman's reagent. Oxidative modification of proteins increased in the digestive gland cells in a dose- and time-dependent manner. The level of nuclear DNA damage was investigated using the comet assay. The results revealed that polyphenolic acids induce single and double-strand breaks in DNA. The highest changes were observed for tannic and gallic acids and the smallest ones for ellagic acid. 1h of DNA repair process was also studied using the same method. The data obtained in this experiment demonstrate that the most effective DNA repair occurs in the cells exposed to phenolic compounds for 24h. A longer incubation (up to 48 h) does not decrease the capacity of the repair mechanism. The antioxidant activity of the tested phenols was analyzed spectrofluorimetrically using a fluorescence probe DCFH-DA (dichlorofluorescein-diacetate). The experimental data showed that the tested acids can act as antioxidants when used at higher doses (200 and 500 microM) against the reactive oxygen species present in the digestive gland cells. The most effective was ellagic acid, also applied at the smallest dose of 60 microM, in comparison with tannic and gallic acids. In conclusion, our results demonstrate that chosen water-soluble polyphenols, which are located in various plant tissues and are also found in the aquatic environment, can influence organisms living in the water. They can be exposed to these chemicals that cause morphological alterations and changes in certain physiological processes in their organs (i.e. digestive gland cells of bivalve molluscs).

Antioxidative and oxidative changes in the digestive gland cells of freshwater mussels Unio tumidus caused by selected phenolic compounds in the presence of H2O2 or Cu2+ ions

Research on biomarkers as early bioindicators of perturbation in populations and individuals has received increasing interest during recent decades. These ecotoxicity studies allow us to measure the impact of environmental stressors and to monitor and evaluate the degradation or restoration of systems. In the present study we used bivalve molluscs (mussels), which are sensitive biomarkers of aquatic ecosystem pollution, to assess the effects of three polyphenols: tannic acid, ellagic acid and gallic acid. These compounds were used in the 1-60 microM concentration range, alone and in the presence of H(2)O(2) (40 and 100 microM) or Cu(2+) ions (50 microM). The fluorescence probe dichlorofluorescein-diacetate (DCFH-DA) was used to measure reactive oxygen species (ROS). The oxidation of DCFH-DA to the fluorescent DCF (dichlorofluorescein) by the phenolic compounds was investigated spectrofluorimetrically. The results showed that the polyphenols tested can act as antioxidants against the ROS present in the digestive gland cells, but their activity is decreased after incubation with hydrogen peroxide or copper ions. SH-groups were determined spectrophotometrically using Ellman's reagent. The results showed that oxidative modification of proteins increased in a concentration-dependent manner in cells incubated with polyphenols (above 15 microM) alone. Incubation of the cells with phenolic acids and H(2)O(2) or Cu(2+) ions revealed that the phenolic acids had prooxidant properties in all concentrations used except for 1 microM tannic and ellagic acid and 40 microM H(2)O(2). DNA fragmentation was estimated by a fluorescence method using Hoechst 33258/propidium iodine binding. The data showed that the phenolic acids alone and in the presence of hydrogen peroxide or copper ions can induce apoptosis and necrosis. The methods used and results obtained indicate that the polyphenols selected can act not only as antioxidants but also as prooxidants in digestive gland cells of Unio tumidus.

Mutagenic activity promoted by amentoflavone and methanolic extract of Byrsonima crassa Niedenzu

Byrsonima crassa is a plant pertaining to the Brazilian central savannah-like belt of vegetation and popularly used for the treatment of gastric dysfunctions and diarrhoea. The methanol extract contains catechin, tannins, terpenes and flavonoids; both mutagenic potential and antioxidant properties have been ascribed to flavonoids. The mutagenicity of some flavonoids is believed to be associated with the formation of reactive oxygen species and seems to depend on the number and position of hydroxyl groups. In the present study the mutagenic activity of the methanol, chloroform and 80% aqueous methanol extracts, as well as acetate and aqueous sub-fractions, of this medicinal plant were evaluated by Salmonella typhimurium assay, using strains TA100, TA98, TA102 and TA97a, and in mouse reticulocytes. The results showed mutagenic activity of the methanolic extract in the TA98 strain without S9, but no mutagenicity to mouse cells in any of the extracts. The acetate fraction showed strong signs of mutagenicity without S9, suggesting that in this enriched fraction were concentrated the compounds that induced mutagenic activity. The aqueous fraction showed no mutagenic activity. The TLC and HSCCC analyses of the acetate fraction with some standard compounds permitted the isolation of the quercetin-3-O-beta-D-galactopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, amentoflavone, methyl gallate and (+)-catechin, of which only the amentoflavone exhibited positive mutagenicity to TA98 (+S9, -S9).

Cellular and in vivo hepatotoxicity caused by green tea phenolic acids and catechins

Tea phenolic acids and catechins containing gallic acid moieties are most abundant in green tea, and various medical benefits have been proposed from their consumption. In the following, the cytotoxicities of these major tea phenolics toward isolated rat hepatocytes have been ranked and the mechanisms of cytotoxicity evaluated. The order of cytotoxic effectiveness found was epigallocatechin-3-gallate>propyl gallate>epicatechin-3-gallate>gallic acid, epigallocatechin>epicatechin. Using gallic acid as a model tea phenolic and comparing it with the tea catechins and gallic acid-derivative food supplements, the major cytotoxic mechanism found with hepatocytes was mitochondrial membrane potential collapse and ROS formation. Epigallocatechin-3-gallate was also the most effective at collapsing the mitochondrial membrane potential and inducing ROS formation. Liver injury was also observed in vivo when these tea phenolics were administered ip to mice, as plasma alanine aminotransferase levels were significantly increased. In contrast, GSH conjugation, methylation, metabolism by NAD(P)H:quinone oxidoreductase 1, and formation of an iron complex were important in detoxifying the gallic acid. In addition, for the first time, the GSH conjugates of gallic acid and epigallocatechin-3-gallate have been identified using mass spectrometry. These results add insight into the cytotoxic and cytoprotective mechanisms of the simple tea phenolic acids and the more complex tea catechins.

Oxidatively modified proteins and DNA in digestive gland cells of the fresh-water mussel Unio tumidus in the presence of tannic acid and its derivatives

The oxidative effect of tannic acid and its two derivatives (ellagic and gallic acid), naturally occurring plant polyphenols, has been studied on digestive gland cells of the fresh-water mussel Unio tumidus. A spectrophotometric method was used to determine the protein thiol groups after incubation of the cells with the polyphenols at concentrations of 1, 15 and 60 microM. The results showed that the oxidative modification of proteins increased in a concentration-dependent manner but no changes were observed at the concentration of 1 microM. The comet assay (single-cell gel electrophoresis assay) with the formamido-pyrimidine glycosylase (FPG) protein was used to assess oxidative DNA base damage. The cells were treated with polyphenols at the concentrations of 30 and 60 microM and post-incubated with FPG. FPG strongly enhanced DNA damage induced by the polyphenols, indicating that N-7 guanine oxidation is responsible for the observed effect. Using the comet assay in combination with proteinase K we were able to demonstrate the presence of DNA-protein cross-links as the probable cause of the decrease in DNA migration. After treatment of the cells with tannic acid and its metabolites at concentrations of 120, 180 and 240 microM, they were post-incubated with proteinase K. After this treatment an increased DNA migration was observed, indicating the presence of DNA-protein cross-links. We have also used a fluorescence method with Hoechst 33258/propidium iodide DNA-binding dyes to study the extent of DNA fragmentation after exposure of the cells to polyphenols at concentrations of 1, 5 and 60 microM. The results demonstrate that the polyphenols can induce apoptosis and necrosis at higher concentrations (5 and 60 microM). All experimental data suggest that tannic, ellagic and gallic acids at concentrations above 1 microM are able to interact with proteins and DNA, which leads to their degradation or changes in their function.

Mechanism of action of the suppression of herpes simplex virus type 2 replication by pterocarnin A

The purpose of this study was to investigate the in vitro antiviral properties of pterocarnin A, extracted from the bark of Pterocarya stenoptera (Juylandaceae). Results showed that pterocarnin A exhibited anti-herpes simplex virus (HSV) activity. It had a low selectivity index (SI) value and only possessed some level of cell cytotoxic effect at high antiviral concentrations. Mechanism studies demonstrated that pterocarnin A inhibited herpes simplex virus type 2 (HSV-2) from attaching and penetrating into cells. It also actively suppressed HSV-2 multiplication in Vero cells even when added 12 h after infection. This observation indicated that pterocarnin A affected the late stage(s) of HSV-2 infection cycle. Pterocarnin A also significantly reduced viral infectivity at high concentrations. From these observations, it was concluded that pterocarnin A suppressed both early and late in the replication cycle of HSV-2. The various modes of action of pterocarnin A in interfering with certain steps of viral infection thus merit further investigation.

Antioxidant and pro-oxidant effects of tannins in digestive cells of the freshwater mussel Unio tumidus

Bivalve molluscs, particularly mussels, are sensitive biomarkers of aquatic ecosystem pollution. The tannins, water-soluble plant polyphenols, may play an important role in this environment and, mainly as a consequence of interaction with pollutants, their toxicity may change. We studied three naturally occurring compounds, tannic acid, ellagic acid and gallic acid, for their ability to modulate DNA damage produced by these tannins alone and in the presence of the oxidative stress inducer H(2)O(2), in cells of the digestive gland of mussels (Unio tumidus). After the treatment of the cells with polyphenols at different concentrations (1, 5, 15, 30, 60, 80, 100, 120, 180, 240 microM) and with hydrogen peroxide in the range of 0.04 and 0.1mM, single-strand breaks (ssb) in DNA were investigated, using the comet assay. The ability of phenolic acids to decrease DNA damage through their antioxidant properties was also assessed. The results show that the phenols, which are known as antioxidative agents, could also act as pro-oxidants. They induced ssb in DNA of the digestive gland at concentrations higher that 10 microM, but lower doses (1 and 5 microM) did not contribute to the DNA damage. This study was also designed to evaluate the protective effect of these tannins against H(2)O(2)-mediated DNA damage in the cells. In this treatment, the two concentrations (1 and 5 microM) significantly decreased the amount of lesions induced by H(2)O(2) (0.04 and 0.1mM). In conclusion, our results demonstrate that antioxidative properties of tannins may change to pro-oxidative activities at the higher concentrations. This suggests that the biologic actions of these compounds may be rather complicated.

Effects of tannins on Chinese hamster cell line B14

Tannins, naturally occurring plant phenols, have been recognized as antioxidants, but toxic effects have also been observed. In the current investigation, the interaction of this type of compounds with Chinese hamster cells (cell line B14) has been examined. This study reports on the results of experiments in which B14 cells were exposed to tannins: tannic, ellagic and gallic acids in the concentration range 15-240 microM. The cytotoxic and genotoxic effects of these compounds were studied. The colorimetric MTT assay to assess cytotoxicity and the Comet assay for detection of DNA damage were used. In this paper, we also demonstrated the influence of tannins on the fluidity of the plasma membrane. This experiment was carried out by a spectrofluorometric method using two fluorescent probes: 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) and 12-(9-anthroyloxy)stearic acid (12-AS). The tannins increased the fluidity in the internal region of the lipid bilayer, but no changes at the surface of the plasma membrane were observed. The results of the MTT assay showed that tannins could decrease the viability of cells and that their cytotoxicity was highest at the concentration of 60 microM. The degree of toxicity of these compounds was not correlated with the concentration used. The data obtained from the Comet assay showed that the tannins could also contribute to formation of DNA single-strand breaks.

Genotoxic and antigenotoxic effects of catechin and tannins from the bark of Hamamelis virginiana L. in metabolically competent, human hepatoma cells (Hep G2) using single cell gel electrophoresis

The genotoxic and antigenotoxic activities of catechin, hamamelitannin and two proanthocyanidin fractions prepared from the bark of Hamamelis virginiana L. were investigated in a human derived, metabolically competent hepatoma cell line (Hep G2) using single cell gel electrophoresis (SCGE) for the detection of DNA-damage. DNA-migration was calculated as Olive tail moment (OTM). Catechin and a low-molecular weight proanthocyandin fraction (W(M)) caused only slight increases of OTM up to concentrations of 166 microg/ml whereas hamamelitannin and the proanthocyandin fraction with higher molecular weight (W(A)) led to a two-fold enhancement of OTM at the same concentrations. These effects were dose-independent. Treatment of the cells with the test compounds in a dose-range of 2-166 microg/ml prior to the exposure to benzo(a)pyrene (B(a)P, 10 microM, 2.5 microg/ml) led to a significant reduction of induced DNA damage which was dose-dependent for all test compounds, except for hamamelitannin. The inhibitory effects of proanthocyanidins were stronger than those of catechin and hamamelitannin; the lowest effective concentrations were about 2 microg/ml. In order to clarify the mechanisms of protection, possible effects of the test compounds on enzymes involved in toxification and detoxification of B(a)P were investigated. While B(a)P toxification by cytochrome P450 was not inhibited by the test compounds, detoxification by glutathion-S-transferase (GST) was induced by catechin and W(M). Combination experiments with the ultimate metabolite of B(a)P, (+/-)-anti-benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE; 5 microM, 1.5 microg/ml), revealed strong inhibitory effects, indicating that the observed protective effects were caused by scavenging of the ultimate mutagen by the test compounds. Exposure of Hep G2 cells to the test compounds after B(a)P treatment did not influence B(a)P induced DNA damage, demonstrating that repair mechanisms were not affected.

Effect of lignins and their precursors on nitric oxide, citrulline and asparagine production by mouse macrophage-like Raw 264.7 cells

Lignins, tannins and flavonoids are commonly found polyphenols. Among these polyphenols, lignins, polymers of phenylpropenoids complexed with polysaccharides, were the least cytotoxic and most potently stimulated the production of nitric oxide (NO), citrulline and asparagine by mouse macrophage-like Raw 264.7 cells. The maximum production of these substances reached the level attained by lipopolysaccharide (LPS). However, epigallocatechin gallate, phenylpropenoid monomers (ferulic acid, caffeic acid) and gallic acid (component unit of tannin) were inactive. These data suggest that the macrophage-stimulation activity of polyphenols depends, at least in part, on their molecular weight or structural configuration. There was a positive relationship between the extent of asparagine production and that of NO or citrulline. Western blot analysis demonstrated that both lignins and LPS elevated the cellular level of asparagine synthetase. The present study suggests the possible link between the stimulated asparagine production and macrophage activation.

Flavonoids uptake and their effect on cell cycle of human colon adenocarcinoma cells (Caco2)

Green tea, mainly through its constituents epigallocatechin gallate, epigallocatechin, epicatechin gallate and epicatechin, has demonstrated anticarcinogenic activity in several animal models, including those for skin, lung and gastro-intestinal tract cancer, although less is known about colorectal cancer. Quercetin, the major flavonoid present in vegetables and fruit, exerts potential anticarcinogenic effects in animal models and cell cultures, but less is known about quercetin glucosides. The objectives of this study were to investigate (i) the antioxidant activity of the phenolic compounds epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside; (ii) the cytotoxicity of different concentrations of epicatechin, epigallocatechin gallate, and gallic acid; (iii) the cellular uptake of epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside and (iv) their effect on the cell cycle. Human colon adenocarcinoma cells were used as experimental model. The results of this study indicate that all dietary flavonoids studied (epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside) show a significant antioxidant effect in a chemical model system, but only epigallocatechin gallate or gallic acid are able to interfere with the cell cycle in Caco2 cell lines. These data suggest that the antioxidant activity of flavonoids is not related to the inhibition of cellular growth. From a structural point of view, the galloyl moiety appears to be required for both the antioxidant and the antiproliferative effects.

Isolation, identification, and characterization of compounds from acer rubrum capable of oxidizing equine erythrocytes

OBJECTIVE

To identify compounds in Acer rubrum that cause hemolysis or oxidation of equine erythrocytes and determine whether these toxins are found in other Acer spp.

SAMPLE POPULATION

Equine erythrocytes.

PROCEDURE

Washed erythrocytes were incubated with extracts and fractions of Acer spp that were separated by thin layer chromatography. Methemoglobin and hemolysis were measured spectrophotometrically. Compounds within Acer spp fractions associated with cell oxidation or hemolysis were identified by gas chromatography-mass spectrometry.

RESULTS

Erythrocytes incubated separately with either A. rubrum, A. saccharum, or A. saccharinum extracts had increased methemoglobin formation, compared with extract-free control samples. Two Acer spp fractions had toxic effects on erythrocytes in vitro. A major component of the Acer fraction that caused a significant amount of methemoglobin formation was identified as gallic acid. An amount of gallic acid equivalent to that found in A. rubrum extract significantly increased methemoglobin, compared with extract-free control erythrocytes, but caused less methemoglobin formation than A. rubrum extracts did. A potential co-oxidant, 2,3-dihydro-3,5-dihydroxy-6-methoxy-4H-pyran-4-one, was found in the A. rubrum extract and may have been responsible for increasing methemoglobin formation. A second A. rubrum fraction caused methemoglobin formation and significant hemolysis. A. saccharum and A. saccharinum extracts caused hemolysis but less than the A. rubrum extracts did.

CONCLUSION AND CLINICAL RELEVANCE

Oxidants in A. rubrum are also found in A. saccharum and A. saccharinum, and the ingestion of A. saccharum and A. saccharinum poses a potential threat to horses.

Cytogenetic effects of propyl gallate in CHO-K1 cells

We investigated whether propyl gallate (PG) can induce sister-chromatid exchanges (SCEs) and chromosomal aberrations (CAs) in CHO-K1 cells. In the absence of an exogeneous metabolizing system, treatments with 0.25-1.5mM PG in plugged flasks for 3h resulted in increases in SCEs, CAs, and endoreduplications (ERDs), which were followed by an increase in the percentage of cells showing cell-cycle delay. At the end of the treatment, a decrease in PG concentration and production of PG dimer and ellagic acid (EA) in the medium were detected, indicating that PG had autoxidized. EA, an oxide of PG, was not genotoxic even at 0.3mM, the maximum concentration soluble in the medium. Several oxygen radical scavengers (superoxide dismutase (SOD), catalase, glutathione and o-phenanthroline (OP)) and an inhibitor of catalase activity (3-amino-1,2,4-triazole (AT)), did not significantly influence PG genotoxicity. When PG autoxidation was suppressed by low pH (6.8) or a 5% CO(2) atmosphere, cell-cycle delay intensified and induction of SCEs and CAs occurred even at the lowest PG dose (0.1mM). When PG (0.5mM) was assayed in the presence of S9 (1.5-9%), gallic acid (GA), a metabolite of PG, was generated in direct proportion to the S9 concentration, while cell-cycle delay and genotoxic effects varied inversely with S9 concentration at the levels over 3%. GA also autoxidized and at >or=0.5mM it induced SCEs. Both catalase and AT suppressed the induction of SCEs by GA or inhibited cell proliferation, indicating that H(2)O(2) participated in the effects. In conclusion, PG in the presence or absence of S9 can induce SCEs, CAs, and ERDs, and the oxides, metabolites and oxygen-free radicals generated during the treatment are partly responsible for these effects.

Subchronic toxicity study of gallic acid by oral administration in F344 rats

Subchronic toxicity of gallic acid (GA) was investigated in F344 rats by feeding diet containing 0, 0.2, 0.6, 1.7 and 5% GA for 13 weeks. Each group consisted of 10 rats of each sex. Toxicological parameters included clinical signs, body weight, food consumption, hematology, blood biochemistry, organ weights and histopathological assessment. Body weight gain in the 5% GA-treated animals of both sexes from week 1 to the end of the experiment was significantly lower than that of the untreated controls. Toxic effects following administration of 0.6% or more in males and 5% in females included reduction of hemoglobin concentration, hematocrit and red blood cell counts and increase in reticulocytes. Histopathologically, extramedullary hematopoiesis, hemosiderin deposition and congestion appeared in the spleens of 5% GA-treated animals, suggesting development of hemolytic anemia. In addition, centrilobular liver cell hypertrophy, reflected in increase in liver weight, was observed in animals of both sexes from 1.7%. In the kidney, Berlin blue-negative brown pigment deposition in the proximal tubular epithelium was observed at 5% GA. However, the severity of these pathological changes was weak. Based on the present toxicology data, 0.2% was determined to be a no-observed-adverse-effect level (NOAEL) in rats. This level was translated into 119 and 128 mg/kg/day, respectively for male and female rats.

Cytotoxic activity of gallic acid against liver metastasis of mastocytoma cells P-815

Gallic acid (3,4,5-trihydroxy benzoic acid), a naturally occurring plant phenol, inhibited the proliferation of metastatic tumor cells, such as P815 murine mastocytoma, B16 murine melanoma and L5178 murine lymphoma cells at IC50s of 6.5, 8.0 and 3.6 microg/ml, respectively. P815 mastocytoma cells are known to metastasize specifically to the liver. When DBA/2 mice, injected intravenously with P815 cells, were treated with gallic acid at a concentration of 50 mg/kg, the number of nodules in the liver and serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT), which had increased as liver metastasis progressed, decreased. However, gallic acid itself did not show a liver protective effect though the life span of DBA/2 mice was extended by gallic acid treatment. These results suggest that gallic acid is able to inhibit liver metastasis, by killing P815 cells metastasized to the liver.

Assessment of the no-observed-adverse-effect level (NOAEL) of gallic acid in mice

Gallic acid is a naturally occurring plant phenol obtained by the hydrolysis of tannins and is known to show some pharmacological activities. The purpose of this paper is to establish the safety of gallic acid in mice. In this study, acute administration of gallic acid even at a dose as high as 5 g/kg body weight did not produce any signs of toxicity or mortality. In the subacute study, gallic acid at a dose of 1000 mg/kg body weight did not significantly alter the hematological parameters. Further, no appreciable change was noted in the various biochemical parameters such as SGOT and SGPT, as well as many serum constituents such as protein, cholesterol, urea and bilirubin. Therefore, from this study, it may be concluded that gallic acid is non-toxic up to a level of 5000 mg/kg body weight, when given orally. In addition, the subacute study indicated the absence of cumulative toxicity, as reflected by the non-significant alterations in the parameters investigated. The NOAEL was 5000 mg/kg body weight, the highest dose tested.

Biological characterization of eugeniin as an anti-herpes simplex virus type 1 compound in vitro and in vivo

Eugeniin exhibits antiviral activity against acyclovir and phosphonoacetic acid (PAA)-resistant herpes simplex virus type 1 (HSV-1) as well as the wild-type HSV-1 in vitro. In this study, we characterized the biological activity of eugeniin in cutaneously HSV-1-infected mice and its interaction with HSV-1 DNA polymerase. The oral and intraperitoneal administrations of eugeniin at 0.3 mg/kg showed similar therapeutic efficacy in retarding the development of skin lesions of HSV-1-infected mice. The two routes of administration at 6 or 50 mg/kg significantly prolonged the mean survival times and/or reduced mortality without toxicity. The oral administration of eugeniin at 50 mg/kg reduced virus yields in the skin and brain of infected mice. Thus, the therapeutic efficacy of oral administration at the various doses of eugeniin was similar to that of intraperitoneal administration, suggesting that the oral bioavailability of eugeniin was high with respect to absorption. Furthermore, the anti-HSV-1 activity of eugeniin was characterized by isobolograms analyzing its combined effects with acyclovir or PAA in HSV-1-infected Vero cells. Eugeniin enhanced the anti-HSV-1 activity of acyclovir but was suggested to be antagonistic with PAA. The interaction of eugeniin and PAA on the activity of partially purified HSV-1 DNA polymerase suggested that eugeniin interacted with the polymerase in the vicinity of PAA-binding site. Thus, eugeniin showed different anti-HSV-1 action from acyclovir and PAA and therapeutic anti-HSV-1 activity in mice.

Derivatives of gallic acid induce apoptosis in tumoral cell lines and inhibit lymphocyte proliferation

The effect of gallic acid (3,4,5-trihydroxybenzoic acid) and its alkyl esters (methyl, propyl, octyl, and lauryl) has been studied on several tumoral and nontumoral cells. Three types of behavior have been observed; the first type is represented by the mouse B cell lymphoma Wehi 231 cell line in which death occurs according to the biochemical characteristics of classical apoptosis showing the DNA ladder fragmentation pattern. The second type is represented by the mouse fibroblast L929 cell line in which morphological characteristics such as cell shrinkage, chromatin condensation, and appearance of apoptotic bodies can be evidenced by microscopical observation. However, the typical DNA fragmentation is absent. Peripheral blood lymphocytes are representative of a third type of behavior. In a resting state they can withstand higher concentrations of these compounds. If the drug is washed, they proliferate normally upon the addition of the mitogen phytohemagglutinin (PHA). However, if the drug is added in the presence of PHA, a clear antiproliferative effect can be demonstrated. A special interest for these compounds stems from the fact that some of them are currently used as antioxidant food additives with the European Community codes E-310 (propylgallate), E-311 (octylgallate), and E-312 (laurylgallate).

Effect of cysteine, N-acetyl-L-cysteine and glutathione on cytotoxic activity of antioxidants

The effect of twenty amino acids on the radical intensity of four antioxidants (sodium L-ascorbate, sodium 5,6-benzylidene-L-ascorbate, gallic acid, caffeic acid) was investigated, using ESR spectroscopy. Methionine and methional did not significantly affect the radical intensity of these antioxidants. Methionine sulfoxide slightly enhanced the radical intensity of sodium ascorbate and sodium 5,6-benzylidene-L-ascorbate, but did not that of gallic acid and caffeic acid. Cysteine, N-acetyl cysteine and glutathione significantly reduced the radical intensity and cytotoxic activity of these antioxidants except for sodium 5,6-benzylidene-L-ascorbate. The other amino acids were inactive. The present study further supports that these antioxidants induce cytotoxicity via their pro-oxidant action.

Effect of alpha-tocopherol on cytotoxicity induced by UV irradiation and antioxidants

The addition of DL-alpha-tocopherol (vitamin E) at the time of UV irradiation only marginally protects cells from UV-induced cytotoxicity. However, a protective effect of alpha-tocopherol emerged when it was added to the cells before UV irradiation, alpha-Tocopherol was progressively and dose-dependently incorporated into the cells. Washout experiments showed that the intracellular concentration of alpha-tocopherol decreased with an approximate half-life of 14-20 hours, due to the release from the cells and dilution by cell proliferation. Pretreatment of the cells with alpha-tocopherol significantly increased the resistancy against the cytotoxic action of UV irradiation and antioxidants such as sodium ascorbate, gallic acid, n-propyl gallate and caffeic acid. ESR spectroscopy showed that alpha-tocopherol enhanced the ascorbyl radical intensity, whereas it reduced caffeic acid radical intensity, without affecting the radical intensity of gallic acid and n-propyl gallate. Both control and treated cell lysates scavenged superoxide anion (generated by xanthine-xanthine oxidase reaction) and hydroxyl radical (generated by Fenton reaction) to a comparable extent. The present study suggests that the protective effect of alpha-tocopherol might be derived from its incorporation into the cell membranes rather than its scavenging activity.

Effect of copper and iron ions on cytotoxicity induced by ascorbate, gallate and caffeate

Four antioxidants, sodium ascorbate, gallic acid, n-propyl gallate and caffeic acid, induced apoptotic cell death in human promyelocytic leukemic HL-60 cells. The effects of all these compounds were enhanced by CuCl2 or deferoxamine mesylate, an iron chelator, but were reduced by FeCl3. ESR spectroscopy showed that both CuCl2 and FeCl3 enhanced the ascorbyl radical intensity, but reduced the gallate and caffeate radical intensity. The present data demonstrate that copper and iron ions modify the cytotoxic activity of these antioxidants differently and their radical intensity is not the sole determinant of cytotoxic activity.

Neutrophil degranulation and superoxide production induced by polychlorinated biphenyls are calcium dependent

2,2',4,4'-Tetrachlorobiphenyl (TCB), a polychlorinated biphenyl (PCB), alters neutrophil functions in vitro by unknown mechanisms. The role of calcium in mediating PCB stimulation of neutrophil function was investigated. Peritoneal neutrophils were isolated from retired breeder, male, Sprague-Dawley rats. Neutrophils were incubated with 10 micrograms/ml 2,2',4,4'-TCB prior to stimulation with phorbol myristate acetate (PMA), and superoxide anion (O2-) production was measured. 2,2',4,4'-TCB alone elicited O2- production and potentiated the response to PMA. When neutrophils were incubated in calcium-free medium, the ability of TCB to stimulate O2- production and to potentiate the response to PMA was abolished. The absence of extracellular calcium did not alter the response to PMA alone. TMB-8, an antagonist of the mobilization of intracellular calcium, inhibited O2- production in response to 2,2',4,4'-TCB stimulation but not to PMA. Degranulation of neutrophils, measured by release of myeloperoxidase, occurred upon exposure to 10 micrograms/ml 2,2',4,4'-TCB alone. This response was increased by cotreatment with the calcium ionophore A23187. 2,3,4,5-TCB, a mono-ortho-substituted PCB congener, potentiated O2- production in response to PMA stimulation by a mechanism that was partly dependent on the presence of extracellular calcium. This congener also stimulated neutrophils to release myeloperoxidase. 3,3',4,4'-TCB, a coplanar congener with high affinity for the Ah receptor, did not elicit neutrophil degranulation. These results indicate that TCBs affect neutrophil function in vitro through signal transduction pathways that appear to be calcium dependent.

Induction of aneuploidy in Chinese hamster oocytes following in vivo treatments with trimethoxybenzoic compounds and their analogues

Many inhibitors of tubulin polymerization have a trimethoxybenzene ring in their molecules. Such trimethoxybenzoic compounds and their analogues may therefore have a potency to induce meiotic nondisjunction of oocytes. In this study, a single dose of reserpine (0.5 microgram/g body weight), podophyllotoxin (20.0 micrograms/g b.w.), trimethoxybenzoic acid (500.0 micrograms/g b.w.) or vinblastine sulfate (3.0 micrograms/g b.w.) was injected intraperitoneally to mature female Chinese hamsters at the onset of the first meiotic spindle formation of oocytes. Within 6 h after spontaneous ovulation, MII oocytes were collected from the oviducts for morphological examination and cytogenetic analysis. The incidence of morphologically abnormal oocytes with unusually large first polar body or bodies increased significantly after the treatment with reserpine (18/202; 8.9%), podophyllotoxin (28/172; 16.3%) and vinblastine sulfate (63/197; 32.0%), as compared with the control (3/214; 1.4%). Chromosome analysis of oocytes revealed that podophyllotoxin and vinblastine sulfate were effective in inducing aneuploidy (62/154; 40.3% and 128/156; 82.1% vs. 3/198; 1.5% of the control) by inhibiting the formation of spindle microtubules at the first meiosis. Aneuploids were found more frequently in morphologically abnormal oocytes than in normal oocytes. No aneugenic activity of reserpine and trimethoxybenzoic acid was observed. These results indicate that trimethoxybenzoic compounds do not necessarily exhibit aneugenic activity.

Effects of various calcium antagonists in isolated perfused hearts from diabetic and age-matched control rats

The purpose of this study was to examine the effects of several calcium antagonistic drugs on left ventricular contraction (isovolumetric) and coronary flow in isolated perfused hearts from streptozotocin diabetic rats compared to age-matched controls, thereby hoping to throw further light on the changes in Ca2+ handling that occur in the diabetic heart. In the presence of Ca2+ (0.9-9.9 mM) left ventricular pressure (LVP) was not significantly different in either type of heart. From cumulative dose-response curves, pD2 values of various calcium antagonists for the negative inotropic activity were determined in diabetic and control hearts. The pD2 values for several calcium antagonists were significantly greater in diabetic hearts than in controls: 5.72 vs. 4.99 for diltiazem, 6.88 vs. 6.60 for verapamil, and 8.42 vs. 8.04 for (-)-devapamil. In hearts from diabetic rats, LVP was also more sensitive to TMB-8 compared with controls: a higher pEC20 value (instead of the pD2 value) was found (5.47 vs. 5.16). The pD2 values for (+)-devapamil, nifedipine, and ryanodine were not significantly different in either type of heart. Calcium-entry blockers increased the coronary flow in control hearts (range 60-80% of the initial flow). However, the increase in flow was significantly greater in diabetic hearts than in the controls (95-128%). TMB-8 and ryanodine had no effect on coronary flow in both types of hearts. In conclusion, the changes in sensitivity of LVP to several calcium antagonists may support a different Ca2+ handling in diabetic hearts compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Methyl gallate, methyl-3,4,5-trihydoxybenzoate, is a potent and highly specific inhibitor of herpes simplex virus in vitro. II. Antiviral activity of methyl gallate and its derivatives

Methyl gallate (MG), methyl-3,4,5-trihydroxybenzoate, was highly active against herpes viruses as determined by plaque reduction assay. Herpes simplex virus type 2, MS strain, was sensitive to MG at a mean 50% inhibitory concentration (IC50) of 0.224 micrograms/ml in monkey kidney cells. MG was specific for herpes viruses with the relative sensitivity HSV-2 greater than HSV-1 greater than CMV. Two RNA viruses tested were significantly less sensitive to MG. The structural components of MG which modulate the anti-herpetic activity were identified by analysis of chemical analogues. Our structural analyses indicated that three hydroxyl groups were required but were not sufficient for the anti-herpetic action of MG. The presence and chain length of the alkyl ester were also important to the anti-herpetic activity of MG. Methyl gallate may interact with virus proteins and alter the adsorption and penetration of the virion.

Induction of forestomach lesions in rats by oral administrations of naturally occurring antioxidants for 4 weeks

The effects of naturally occurring antioxidants on rat forestomach epithelium were compared with those of synthetic antioxidants, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), of which the former is a known forestomach carcinogen. Groups of five F344 male rats were given diet containing BHA, BHT, gallic acid, syringic acid, sesamol, caffeic acid, chlorogenic acid, ferulic acid, eugenol or esculin for 4 weeks at a level of 0.7% for BHT or 2% for other compounds. Histological examination of the forestomach showed that BHA induced hyperplasia mainly in the prefundic region near the esophageal orifice, caffeic acid induced pronounced hyperplasia throughout the forestomach epithelium, and sesamol induced large ulcers and hyperplasia in the central region. Thus, these naturally occurring antioxidants showed different toxicities and abilities to induce hyperplasia in the rat forestomach.

Toxicology of gallates: a review and evaluation

The propyl, octyl and dodecyl esters of gallic acid have been studied extensively in a large number of animal experiments involving oral dosing. Experimental data on general toxicity and studies on reproduction, teratogenicity and mutagenicity are also available. Most of the key toxicity studies, however, date back to the 1950s, do not meet current standards of toxicity testing and do not provide evidence for carcinogenic or mutagenic action of the gallates. Mutagenicity studies with octyl gallate and dodecyl gallate are lacking. The biokinetics of propyl gallate apparently differ from those of octyl and dodecyl gallate, the octyl and dodecyl esters being absorbed and hydrolysed to a lesser degree than the propyl ester. In toxicity studies with propyl gallate, growth retardation, anaemia, kidney and liver changes and hyperplasia of the forestomach were the most prominent effects at dose levels above 10,000 mg/kg feed. At 5000 mg/kg feed, liver enzyme induction was seen. In the available studies with octyl gallate or dodecyl gallate as the test compound, effects were found at 3000 mg/kg feed or higher levels. In studies performed with the various gallates, no effects were observed at a dose level of 1000 mg/kg feed, a level that was adopted as the no-effect level by the FAO/WHO Joint Expert Committee on Food Additives (JECFA) in 1976. This committee established an acceptable daily intake (ADI) for man of 0.2 mg/kg body weight (as a sum of propyl, octyl and dodecyl gallates). A re-evaluation of the toxicity of gallates indicates that a 'classic' long-term toxicity study of propyl gallate meeting current standards is required. As yet, the available toxicological evidence indicates that gallates may be used safely as antioxidants.

[Toxicological study of the long-term effects of the antioxidant dodecyl gallate on albino rats]

Toxicity of the antioxidant dodecyl gallate was studied in 150-day experiments on male white rats. The antioxidant was administered intragastrically in doses of 250, 50 and 10 mg/kg bw. The general status and behavior of the animals, the survival rate, weight gain, peripheral blood, the amount of urea, total serum protein, soluble proteins of the liver and kidneys, and activity of enzymes (AST, ALT, LDH, SDH, glucose-6-phosphate dehydrogenase, alkaline and acid phosphatase of the serum, liver and kidneys, the weight of the internal organs) were studied over time, followed by morbid anatomy studies. Quantitative determination of serum lipids (total fats, total cholesterol, esterified cholesterol, free cholesterol, triglycerides, free fatty acids, triglycerides plus free fatty acids, and phospholipids) was made on the 150th day after the onset of experiments. When administered in a dose of 250 mg/kg, dodecyl gallate produced death of the animals and an increase in the content of triglycerides plus free fatty acids, a decrease in the weight of the spleen and morphological alterations in the liver, kidneys and spleen. The dose 50 mg/kg was also toxic. It brought about changes in the activity of serum and liver AST, an increase in the content of TF, TG, FFA, TG plus FFA and phospholipids, a reduction in the weight of the spleen and pathological changes in the liver, kidneys and spleen. The dose 10 mg/kg is regarded as liminal.