The 10 basic requirements for a scientific paper reporting antioxidant, antimutagenic or anticarcinogenic potential of test substances in in vitro experiments and animal studies in vivo

Antioxidant Synergy in a Mixture of Powder Plant Leaves and Effects on Metabolic Profile, Oxidative Status and Intestinal Morpho-Histochemical Features of Laying Hens

Phenolic antioxidant intake is encouraged to prevent oxidative damage, and antioxidant synergy is considered an advantage in adding polyphenols from varied plants. This study investigated the antioxidant and synergistic interactions among olive leaf (OL), bay laurel (BL), and rosemary (RL) leaf powder mixture (LPM: OL + BL + RL), using in vitro chemical tests [TPC, ORAC, TEAC-ABTS, FRAP; combination index (CI)], and in vivo validation on blood oxidative status, metabolic profile, and intestinal histomorphology in laying hens. The in vitro study indicated a whole higher antioxidant capacity for the LPM than respective single/double-leave combinations. The LPM CI value (IC50, 0.60) indicated a synergistic effect compared to the binary combinations. Thus, the LPM was validated in vivo through dietary supplementation on sixty Lohmann Brown hens (30 weeks old), reared in an indoor-outdoor rearing system divided. The hens were allocated into two experimental groups (n. 30): basal control diet group; and diet supplemented group with 6 g/kg feed of LPM) containing OL, BL, and RL (respectively, at 65.7%:18.9%:15.4%), for 60 days. The LPM improved (p < 0.05) the oxidative status (TAS, FRAP; ROMs, TBARs) and vitamin E level, metabolic and immunological profiles, and it induced region-specific changes in the morphology and carbohydrate composition of mucins along intestinal tracts of the animals. These findings could provide a valuable strategy for identifying synergistic combinations in functional feed formulations for laying hens.

CRIME-Q-a unifying tool for critical appraisal of methodological (technical) quality, quality of reporting and risk of bias in animal research

BACKGROUND

Systematic reviews within the field of animal research are becoming more common. However, in animal translational research, issues related to methodological quality and quality of reporting continue to arise, potentially leading to underestimation or overestimation of the effects of interventions or prevent studies from being replicated. The various tools and checklists available to ensure good-quality studies and proper reporting include both unique and/or overlapping items and/or simply lack necessary elements or are too situational to certain conditions or diseases. Currently, there is no tool available, which covers all aspects of animal models, from bench-top activities to animal facilities, hence a new tool is needed. This tool should be designed to be able to assess all kinds of animal studies such as old, new, low quality, high quality, interventional and noninterventional on. It should do this on multiple levels through items on quality of reporting, methodological (technical) quality, and risk of bias, for use in assessing the overall quality of studies involving animal research.

METHODS

During a systematic review of meningioma models in animals, we developed a novel unifying tool that can assess all types of animal studies from multiple perspectives. The tool was inspired by the Collaborative Approach to Meta Analysis and Review of Animal Data from Experimental Studies (CAMARADES) checklist, the ARRIVE 2.0 guidelines, and SYRCLE's risk of bias tool, while also incorporating unique items. We used the interrater agreement percentage and Cohen's kappa index to test the interrater agreement between two independent reviewers for the items in the tool.

RESULTS

There was high interrater agreement across all items (92.9%, 95% CI 91.0-94.8). Cohen's kappa index showed quality of reporting had the best mean index of 0.86 (95%-CI 0.78-0.94), methodological quality had a mean index of 0.83 (95%-CI 0.78-0.94) and finally the items from SYRCLE's risk of bias had a mean kappa index of 0.68 (95%-CI 0.57-0.79).

CONCLUSIONS

The Critical Appraisal of Methodological (technical) Quality, Quality of Reporting and Risk of Bias in Animal Research (CRIME-Q) tool unifies a broad spectrum of information (both unique items and items inspired by other methods) about the quality of reporting and methodological (technical) quality, and contains items from SYRCLE's risk of bias. The tool is intended for use in assessing overall study quality across multiple domains and items and is not, unlike other tools, restricted to any particular model or study design (whether interventional or noninterventional). It is also easy to apply when designing and conducting animal experiments to ensure proper reporting and design in terms of replicability, transparency, and validity.

Antidiabetic and in vitro antioxidant potential of Mormodica charantia L. fruit in Experimentally Induced Wistar Rat Model of Type 2 Diabetes

BACKGROUND: The liver is a vital organ responsible for regulating the normal glucose homeostasis in the body system, and hepatic glucose metabolic dysregulation is one of the most critical elements in the pathogenesis of DM. METHOD: Twenty-five healthy rats aged seven weeks were divided into the following main groups; non-diabetic, diabetic untreated, diabetic treated with 250 mg/kg and 500 mg/kg of MC fruit, and diabetic treated with Metformin (500 mg/kg). Different models of in vitro antioxidant assays of MC fruit were also determined. RESULTS: The results showed that MC fruit has high antioxidant potential against DPPH, hydrogen peroxide, hydroxyl radicals, good reducing ferric power, significant Inhibition of lipid peroxidation and total antioxidant activities. The FBG levels decreased significantly in MC fruit treatment groups compared to diabetes control (DC) rats. The histology of the hepatic tissue of the diabetic untreated rats revealed a marked depletion in glycogen granules and hepatic DNA. These negative features were ameliorated in the MC fruit treated rats, as consistent glycogen granule storage and improved hepatic DNA presence were observed in the MC fruit treated rats. CONCLUSION: MC fruit reduces blood glucose levels in a diabetic rat model, and it also preserves the hepatic DNA and glycogen granules. MC fruit has a significant in vitro antioxidant activity.

Systematic review of guidelines for internal validity in the design, conduct and analysis of preclinical biomedical experiments involving laboratory animals

Over the last two decades, awareness of the negative repercussions of flaws in the planning, conduct and reporting of preclinical research involving experimental animals has been growing. Several initiatives have set out to increase transparency and internal validity of preclinical studies, mostly publishing expert consensus and experience. While many of the points raised in these various guidelines are identical or similar, they differ in detail and rigour. Most of them focus on reporting, only few of them cover the planning and conduct of studies. The aim of this systematic review is to identify existing experimental design, conduct, analysis and reporting guidelines relating to preclinical animal research. A systematic search in PubMed, Embase and Web of Science retrieved 13 863 unique results. After screening these on title and abstract, 613 papers entered the full-text assessment stage, from which 60 papers were retained. From these, we extracted unique 58 recommendations on the planning, conduct and reporting of preclinical animal studies. Sample size calculations, adequate statistical methods, concealed and randomised allocation of animals to treatment, blinded outcome assessment and recording of animal flow through the experiment were recommended in more than half of the publications. While we consider these recommendations to be valuable, there is a striking lack of experimental evidence on their importance and relative effect on experiments and effect sizes.

Good Laboratory Practice in the Academic Setting: Fundamental Principles for Nonclinical Safety Assessment and GLP-Compliant Pathology Support When Developing Innovative Biomedical Products

Development of new biomedical products necessitates nonclinical safety assessment in animals as a means of assessing potential risk to human patients. Pivotal nonclinical safety studies that support human clinical trials are performed according to Good Laboratory Practice (GLP) guidelines, which are designed to ensure that the study was conducted under carefully controlled conditions using standardized and validated procedures that will yield a reliable, reproducible, and traceable data set. The GLP guidelines established by different regulatory agencies address organizational structure, personnel responsibilities, personnel training practices, quality assurance (ensuring compliance), facilities, equipment, standard operating procedures, study documentation (record keeping), and record and sample retention. Academic institutions engaging in nonclinical safety assessment on-site have multiple options for implementing a GLP quality system. This article outlines the rationale supporting the use of a GLP-compliant or GLP-like quality system in academia and reviews key concepts needed to efficiently and effectively implement GLP in the academic setting. Emphasis is given to provision of GLP-compliant pathology support as (1) pathology data are an essential component of GLP nonclinical safety testing, (2) familiarity with pathology-related GLP procedures typically is gained first outside the academic setting, and (3) microscopic pathology diagnoses and interpretations require special accommodations to ensure that they are undertaken in a GLP-compliant fashion.

A whole-food approach to the in vitro assessment of the antitumor activity of gazpacho

Gazpacho is a traditional cold soup of the Mediterranean diet consisting of a main base of fresh pureed tomato and other vegetables. Tomato and tomato products have demonstrated chemopreventive activity against several types of cancer through in vitro studies, and in animal and clinical research. Here we have applied a whole-food approach for the preclinical assessment of the antitumor potential of gazpacho. Colon cancer cells (HT-29) were exposed to growing concentrations of gazpacho previously digested in vitro to simulate the delivery of bioactive molecules to colon cells after food consumption. The cytotoxicity of gazpacho ingredients was also tested in independent experiments. Programmed cell death by apoptosis was detected by using a multiparametric analysis that combines image-based bright-field and fluorescence cytometry, intracellular ATP level determination and enzymatic activity of caspase-3/7. Modulation of gene expression of key regulatory genes (p53, Bcl-2, BAX, and cyclin D1) was also investigated. Our cytotoxicity data showed that in vitro digestion of samples allowed the delivery of bioactive levels of antitumor phytochemicals to cultured cells. Controlled experiments showed significant repetitive dose and time-response cytotoxicity of gazpacho. Gazpacho digestates caused net cell death of cultures suggesting synergic activity among phytochemicals from its vegetable ingredients. Multiparametric and genetic analyses showed that gazpacho digestates can trigger colon cancer cells death by apoptosis through the activation of caspase cascade. Our results show that coupled in vitro methodology employed can be applied to investigate the antitumor potential of complex food matrixes or combinations of foods in the diet.

Preclinical efficacy in therapeutic area guidelines from the U.S. Food and Drug Administration and the European Medicines Agency: a cross-sectional study

BACKGROUND AND PURPOSE

Therapeutic area guidelines (TAGs) published by the EMA and the FDA offer guidance in planning the launch of a trial in a certain indication. We assessed and compared the guidance on preclinical efficacy of all available TAGs from EMA and FDA.

EXPERIMENTAL APPROACH

EMA and FDA websites and databases were searched for all TAGs. A mixed deductive and inductive approach was applied to analyse and cluster content for preclinical efficacy.

KEY RESULTS

A total of 114 EMA and 120 FDA TAGs were identified, covering 126 indications. Our core finding is that 75% of EMA TAGs and 58% from the FDA TAGs do not offer any guidance on preclinical efficacy. TAGs varied widely on the extent, nature and detail of guidance.

CONCLUSIONS AND IMPLICATIONS

Guidance on preclinical efficacy in a consistent, comprehensive and explicit way that still allows for justified deviations is an important but neglected aspect of transparency for drug development. This transparency would help sponsors in designing preclinical studies and in negotiating more efficiently with regulators.

Medicinally important aromatic plants with radioprotective activity

Aromatic plants are often used as natural medicines because of their remedial and inherent pharmacological properties. Looking into natural resources, particularly products of plant origin, has become an exciting area of research in drug discovery and development. Aromatic plants are mainly exploited for essential oil extraction for applications in industries, for example, in cosmetics, flavoring and fragrance, spices, pesticides, repellents and herbal beverages. Although several medicinal plants have been studied to treat various conventional ailments only a handful studies are available on aromatic plants, especially for radioprotection. Many plant extracts have been reported to contain antioxidants that scavenge free radicals produced due to radiation exposure, thus imparting radioprotective efficacy. The present review focuses on a subset of medicinally important aromatic plants with radioprotective activity.

Implementation of Good Laboratory Practices (GLP) in basic scientific research: Translating the concept beyond regulatory compliance

The principles of Good Laboratory Practices (GLPs) are mainly intended for the laboratories performing studies for regulatory compliances. However, today GLP can be applied to broad disciplines of science to cater to the needs of the experimental objectives, generation of quality data and assay reproducibility. Considering its significance, it can now be applied in academics; industries as well as government set ups throughout the world. GLP is the best way to promote the reliability, reproducibility of the test data and hence facilitates the international acceptability. Now it is high time to translate and implement the concept of GLP beyond regulatory studies. Thus, it can pave the way for better understanding of scientific problems and help to maintain a good human and environmental health. Through this review, we have made an attempt to explore the uses of GLP principles in different fields of science and its acceptability as well as looking for its future perspectives.

Utilization of cytogenetic biomarkers as a tool for assessment of radiation injury and evaluation of radiomodulatory effects of various medicinal plants - a review

Systematic biological measurement of “cytogenetic endpoints” has helped phenomenally in assessment of risks associated with radiation exposure. There has been a surge in recent times for the usage of radioactive materials in health care, agriculture, industrial, and nuclear power sectors. The likelihood of radiation exposure from accidental or occupational means is always higher in an overburdened ecosystem that is continuously challenged to meet the population demands. Risks associated with radiation exposure in this era of modern industrial growth are minimal as international regulations for maintaining the safety standards are stringent and strictly adhered to, however, a recent disaster like “Fukushima” impels us to think beyond. The major objective of radiobiology is the development of an orally effective radio-modifier that provides protection from radiation exposure. Once available for mass usage, these compounds will not only be useful for providing selective protection against accidental and occupational radiation exposure but also help to permit use of higher doses of radiation during treatment of various malignancies curtailing unwarranted adverse effects imposed on normal tissues. Bio-active compounds isolated from natural sources enriched with antioxidants possess unique immune-modulating properties, thus providing a double edged benefit over synthetic radioprotectors. We aim to provide here a comprehensive overview of the various agents originating from plant sources that portrayed promising radioprotection in various experimental models with special emphasis on studies that used cytogenetic biomarkers. The agents will include crude extracts of various medicinal plants, purified fractions, and herbal preparations.

Antidiabetic and in vitro antioxidant potential of Hybanthus enneaspermus (Linn) F. Muell in streptozotocin-induced diabetic rats

OBJECTIVE

To evaluate antidiabetic and antioxidant potential of Hybanthus enneaspermus in different models.

METHODS

The oral glucose tolerance test (OGTT) and normoglycemic effect of alcoholic extract of Hybanthus enneaspermus (AHE) were evaluated at a dose of 125, 250 and 500 mg/kg p.o. while hypoglycemic activity and effect on body weight were tested at 250 and 500 mg/kg p.o. per day for 21 days in Streptozotocin (STZ) induced diabetic rats. Further, glucose uptake by hemidiaphram was also evaluated. The total polyphenolic and flavonoid were determined and their correlation with various antioxidant assays was also determined.

RESULTS

The results showed high level of phenolic content in AHE. AHE also exhibited higher total antioxidant capacity, good reducing power and a significant scavenger of reactive oxygen species like DPPH radical, nitric oxide, hydrogen peroxide and deoxyribose. Furthermore there was a significant increase in the body weight and decrease in the blood glucose level on treatment with the AHE. AHE increased glucose uptake on isolated rat hemi-diaphragm compared to control group.

CONCLUSIONS

AHE reduce blood glucose level in STZ-induced diabetic model. It does not show significant effect in normoglycemic study but showes significant effect in OGT. AHE has significant antioxidant activity, which may be attributed to high phenolic content.

Instruments for assessing risk of bias and other methodological criteria of published animal studies: a systematic review

BACKGROUND

Results from animal toxicology studies are critical to evaluating the potential harm from exposure to environmental chemicals or the safety of drugs prior to human testing. However, there is significant debate about how to evaluate the methodology and potential biases of the animal studies. There is no agreed-upon approach, and a systematic evaluation of current best practices is lacking.

OBJECTIVE

We performed a systematic review to identify and evaluate instruments for assessing the risk of bias and/or other methodological criteria of animal studies.

METHOD

We searched Medline (January 1966-November 2011) to identify all relevant articles. We extracted data on risk of bias criteria (e.g., randomization, blinding, allocation concealment) and other study design features included in each assessment instrument.

DISCUSSION

Thirty distinct instruments were identified, with the total number of assessed risk of bias, methodological, and/or reporting criteria ranging from 2 to 25. The most common criteria assessed were randomization (25/30, 83%), investigator blinding (23/30, 77%), and sample size calculation (18/30, 60%). In general, authors failed to empirically justify why these or other criteria were included. Nearly all (28/30, 93%) of the instruments have not been rigorously tested for validity or reliability.

CONCLUSION

Our review highlights a number of risk of bias assessment criteria that have been empirically tested for animal research, including randomization, concealment of allocation, blinding, and accounting for all animals. In addition, there is a need for empirically testing additional methodological criteria and assessing the validity and reliability of a standard risk of bias assessment instrument.

Threats to validity in the design and conduct of preclinical efficacy studies: a systematic review of guidelines for in vivo animal experiments

BACKGROUND

The vast majority of medical interventions introduced into clinical development prove unsafe or ineffective. One prominent explanation for the dismal success rate is flawed preclinical research. We conducted a systematic review of preclinical research guidelines and organized recommendations according to the type of validity threat (internal, construct, or external) or programmatic research activity they primarily address.

METHODS AND FINDINGS

We searched MEDLINE, Google Scholar, Google, and the EQUATOR Network website for all preclinical guideline documents published up to April 9, 2013 that addressed the design and conduct of in vivo animal experiments aimed at supporting clinical translation. To be eligible, documents had to provide guidance on the design or execution of preclinical animal experiments and represent the aggregated consensus of four or more investigators. Data from included guidelines were independently extracted by two individuals for discrete recommendations on the design and implementation of preclinical efficacy studies. These recommendations were then organized according to the type of validity threat they addressed. A total of 2,029 citations were identified through our search strategy. From these, we identified 26 guidelines that met our eligibility criteria--most of which were directed at neurological or cerebrovascular drug development. Together, these guidelines offered 55 different recommendations. Some of the most common recommendations included performance of a power calculation to determine sample size, randomized treatment allocation, and characterization of disease phenotype in the animal model prior to experimentation.

CONCLUSIONS

By identifying the most recurrent recommendations among preclinical guidelines, we provide a starting point for developing preclinical guidelines in other disease domains. We also provide a basis for the study and evaluation of preclinical research practice. Please see later in the article for the Editors' Summary.

Inhibition or enhancement by 4 Pacific Island food plants against cancers induced by 2 amino-3-methylimidazo[4,5-f]quinoline in male Fischer 344 rats

A 1-yr carcinogenicity bioassay was conducted in rats fed 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), simultaneously with AIN-76/ high-fat (HF) diet alone, or with 10% starch replaced with kumara, pineapple, coconut, or taro, prepared as for a human diet. All of the non-IQ treated control, kumara, pineapple, or taro but not coconut-fed rats survived to 1 yr. None of the IQ-fed animals survived to 1 yr and although there were minor survival time differences among the groups, none was statistically significant. At sacrifice, IQ/HF controls had tumors in the skin, Zymbal's gland, ear canal, oral cavity, liver, and small intestine, totaling 32 among 20 animals. Kumara-fed rats had a similar tumor distribution but no tumors in the ear or oral cavity, and a total of 27 tumors among 20 animals, whereas pineapple-fed rats showed a somewhat lower tumor incidence (23/20 animals), including no small intestine lesions. Unexpectedly, a higher tumor incidence, especially of skin tumors, was seen in coconut and taro-fed animals (35/20 and 41/20 animals, respectively). In particular, the incidence of malignant liver tumors and gastrointestinal tumors were significantly increased in the taro-fed group in comparison with the kumara group.

Synergistic, additive, and antagonistic effects of food mixtures on total antioxidant capacities

Different foods possess different bioactive compounds with varied antioxidant capacities. When foods are consumed together, the total antioxidant capacity of food mixtures may be modified via synergistic, additive, or antagonistic interactions among these components, which may in turn alter their physiological impacts. The main objective of this study was to investigate these interactions and identify any synergistic combinations. Eleven foods from three categories, including fruits (raspberry, blackberry, and apple), vegetables (broccoli, tomato, mushroom, and purple cauliflower), and legumes (soybean, adzuki bean, red kidney bean, and black bean) were combined in pairs. Four assays (total phenolic content, ferric reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl, radical scavenging capacity, and oxygen radical absorbance capacity) were used to evaluate the antioxidant capacities of individual foods and their combinations. The results indicated that within the same food category, 13, 68, and 21% of the combinations produced synergistic, additive, and antagonistic interactions, respectively, while the combinations produced 21, 54, and 25% synergistic, additive, and antagonistic effects, respectively, across food categories. Combining specific foods across categories (e.g., fruit and legume) was more likely to result in synergistic antioxidant capacity than combinations within a food group. Combining raspberry and adzuki bean extracts demonstrated synergistic interactions in all four chemical-based assays. Compositional changes did not seem to have occurred in the mixture. Results in this study suggest the importance of strategically selecting foods or diets to maximum synergisms as well as to minimum antagonisms in antioxidant activity.

Antioxidant activities of leaf extract of Salvia miltiorrhiza Bunge and related phenolic constituents

Leaf of Salvia miltiorrhiza Bunge, the waste part during the root harvest, is rich in health-promoting phenolics and is a novel resource of natural antioxidants. The acetone and methanol extracts of leaves (AL and ML, respectively) of S. miltiorrhiza were evaluated by various in vitro antioxidant assays. The total phenolic contents of AL and ML were 39.0+/-1.13 and 54.3 +/-1.1mg gallic acid equivalents/g extract tested, respectively. EC(50) of ML was 7.0+/-0.28 microg/mL in DPPH radical scavenging assay and 246.5 +/-10.35 microg/mL in superoxide radical quenching assay. It was also found that ML has prominent effects on the inhibition of linoleic acid oxidation (93.2%), which was equivalent to the positive control, butylated hydroxytoluene (BHT, p>0.05), and was significantly higher than α-tocopherol (VE, p<0.05). The reducing power of leaf extracts was as strong as roots (p>0.05). HPLC and correlation analysis show that salvianolic acid B and rosmarinic acid constitute the most abundant phenolic compounds. They are the major contributors to antioxidant activities. The results suggested that S. miltiorrhiza leaves could be considered as a new potential source of natural phenolic antioxidants for food, pharmaceutical, cosmetics or nutraceutical industries.

Alpinia pricei Hayata rhizome extracts have suppressive and preventive potencies against hypercholesterolemia

The aim of this study was to investigate the effects of 70% ethanol extracts of Alpinia pricei (APE) on lipid profiles and lipid peroxidation. Syrian hamsters were fed a chow-based hypercholesterolemic diet (HCD) for 2 weeks to induce hypercholesterolemia (>250 mg/dl). To evaluate the potency of APE in suppressing hypercholesterolemia, hamsters were then fed HCD plus a high dose (500 mg/kg body weight) or a low dose (250 mg/kg body weight) of APE, or only HCD for another 4 weeks. We found that hypercholesterolemic hamsters fed a high dose of APE had lower serum total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) levels, lower thiobarbituric acid reactive substances (TBARS) and alanine aminotransferase (ALT) activities, lower atherogenic indices (LDL-C/HDL-C and TC/HDL-C ratios), and lower hepatic protein expression of peroxisome proliferators activated receptor gamma (PPARgamma) than hamsters fed a HCD diet. In addition, we also determined the preventive effects of APE on hamsters fed a HCD for 6 weeks. The hypocholesterolemic effects were also found in hamsters co-fed a high dose of APE and HCD for 6weeks. These results suggest that APE has both suppressive and preventive potencies against hypercholesterolemia and has the potency to protect against lipid peroxidation.

Evolution of oxidative stress parameters and response to oral vitamins E and C in streptozotocin-induced diabetic rats

Type I diabetes in humans and streptozotocin (STZ)-induced diabetes in rats has been associated with oxidative stress, but antioxidant therapy has given contradictory results, in part related to the absence of common conditions used to evaluate in-vivo antioxidant properties. This prompted the study of an experimental model of antioxidant therapy in STZ-treated rats. Adult female rats received STZ (50 mgkg(-1)) and were studied 7 or 14 days later. Adipose tissue weight progressively decreased with the time of treatment, whereas plasma triglycerides increased at 7 days, before returning to control values at 14 days after STZ treatment. STZ diabetic rats had increased plasma thiobarbituric acid reacting substances and alpha-tocopherol levels, but the latter variable was decreased when corrected for total lipids. STZ diabetic rats showed a higher GSSG/GSH ratio at Day 14 and lower GSH + GSSG at Day 7 in liver. To evaluate the effect of short-term antioxidant therapy, rats received 5 doses of vitamins C and E over 3 days before being killed on Day 14. Treatment with antioxidants decreased plasma lactic acid and thiobarbituric acid reacting substances, as well as urine 8-isoprostane, and decreased plasma uric acid in controls. Vitamins increased the plasma alpha-tocopherol/lipids ratio only in control rats, although the plasma and liver alpha-tocopherol concentration increased in both groups. STZ diabetic rats showed moderate oxidative stress and treatment with antioxidant vitamins caused a significant change in a selected group of oxidative stress markers, which reflected an improvement in some of the complications associated with this disease. The present experimental conditions can be used as a sensitive experimental model to study the responsiveness of diabetes to other antioxidant interventions.

Toxicity and antioxidant activity in vitro and in vivo of two Fucus vesiculosus extracts

The consumption of seaweeds has increased in recent years. However, their adverse and beneficial effects have scarcely been studied. Two extracts from the brown seaweed Fucus vesiculosus containing 28.8% polyphenols or 18% polyphenols plus 0.0012% fucoxanthin have been obtained and studied to determine their toxicity in mice and rats and also their antioxidant activity. Both extracts were shown to lack any relevant toxic effects in an acute toxicity test following a 4 week daily treatment in rats. The extracts exhibited antioxidant activity in noncellular systems and in activated RAW 264.7 macrophages, as well as in ex vivo assays in plasma and erythrocytes, after the 4 week treatment in rats. Our ex vivo results indicated that compounds from extract 2 may be more easily absorbed and that the antioxidants in their parent or metabolized form are more active. These findings support the view that the daily consumption of F. vesiculosus extract 2 (Healsea) would have potential benefits to humans.

Correlative and quantitative 1H NMR-based metabolomics reveals specific metabolic pathway disturbances in diabetic rats

Type 1 diabetes was induced in Sprague-Dawley rats using streptozotocin. Rat urine samples (8 diabetic and 10 control) were analyzed by 1H nuclear magnetic resonance (NMR) spectroscopy. The derived metabolites using univariate and multivariate statistical analysis were subjected to correlative analysis. Plasma metabolites were measured by a series of bioassays. A total of 17 urinary metabolites were identified in the 1H NMR spectra and the loadings plots after principal components analysis. Diabetic rats showed significantly increased levels of glucose (P < 0.00001), alanine (P < 0.0002), lactate (P < 0.05), ethanol (P < 0.05), acetate (P < 0.05), and fumarate (P < 0.05) compared with controls. Plasma assays showed higher amounts of glucose, urea, triglycerides, and thiobarbituric acid-reacting substances in diabetic rats. Striking differences in the Pearson's correlation of the 17 NMR-detected metabolites were observed between control and diabetic rats. Detailed analysis of the altered metabolite levels and their correlations indicate a significant disturbance in the glucose metabolism and tricarboxylic acid (TCA) cycle and a contribution from gut microbial metabolism. Specific perturbed metabolic pathways include the glucose-alanine and Cori cycles, the acetate switch, and choline metabolism. Detection of the altered metabolic pathways and bacterial metabolites using this correlative and quantitative NMR-based metabolomics approach should help to further the understanding of diabetes-related mechanisms.

How to standardize the multiplicity of methods to evaluate natural antioxidants

A great multiplicity of methods has been used to evaluate the activity of natural antioxidants by using different techniques of inducing and catalyzing oxidation and measuring the end point of oxidation for foods and biological systems. Antioxidant in vitro protocols for foods should be based on analyses at relatively low levels of oxidation under mild conditions and on the formation and decomposition of hydroperoxides. For antioxidant in vivo protocols, widely different methods have been used to test the biological protective activity of phenolic compounds. Unfortunately, many of these protocols have been based on questionable methodology to accurately measure oxidative damage and to assess relevant changes in biological targets. Many studies testing the ex vivo activity of phenolic compounds to inhibit human low-density lilpoprotein (LDL) oxidation have been difficult to evaluate because of the structural complexity of LDL particles and because a multitude of markers of oxidative damage have been used. Although studies with animal models of atherosclerosis have demonstrated the antioxidant effect of phenolic compounds in delaying the progress of this disease, human clinical trials of antioxidants have reported inconsistent and mixed results. Complex mixtures of plant polyphenols have been shown to be absorbed to varying degrees as metabolites in the intestine, but little is known about their interactions, bioavailability, and their in vivo antioxidant activity. Several metabolites identified in human plasma after consuming flavonoids need to be tested for possible nonantioxidant activities. More research and better-designed human studies are required to clarify the complex questions of bioavailability of polyphenols and the factors affecting their in vivo activities. Until we know what relevant in vivo activities to measure, any claims on the biological and health protective effects of natural polyphenolic compounds in our diet are premature.

Bread enriched with green coffee extract has chemoprotective and antigenotoxic activities in human cells

Recent studies have shown that bread supplemented with functional ingredients was more chemoprotective than nonsupplemented bread. Here we investigated components of a German wheat bread supplemented with green coffee antioxidants (GC) to assess basic biological activities in human cells in culture. We analyzed chlorogenic acid (ChA) in the bread and determined antioxidative activities. Human colon (HT29) and liver (HepG2) cells were incubated with GC and with aqueous extracts of freeze-dried breads, after which cell survival (4' ,6-diamino-2- phenylindole dihydrochloride assay) and H(2)O(2)-induced DNA damage (comet assay) were determined. GC and supplemented bread contained 7- and 880-fold more ChA than normal bread and were significantly more antioxidative (ferric reducing ability of plasma assay, 2.9- and 265-fold; Trolox equivalent antioxidant capacity assay, 1.3- and 24-fold, respectively). Treatment of cells for 24 to 72 h with the samples resulted in a significant inhibition of cell survival in a dose-dependent manner. HepG2 liver cells were more susceptible than HT29 colon cells. No genotoxicity or cytotoxicity was observed after treatment of cells with GC, ChA, or the bread samples. H(2)O(2)-induced DNA damage was reduced significantly after treatment with GC, ChA, and supplemented bread. In conclusion, the supplementation of bread with GC improves the chemoprotective property of normal bread under these in vitro cell culture conditions. Supplementation also increases ChA content and antioxidative capacity. The treatment of the cells with supplemented bread increases resistance of colon and liver cells against H(2)O(2), a source of oxidative stress.

Blood mononucleocytes are sensitive to the DNA damaging effects of iron overload--in vitro and ex vivo results with human and rat cells

Iron exposure enhances colorectal carcinogeneis, by producing reactive oxygen species, which damage lipids, proteins and DNA. We recently demonstrated that ferric-nitrilotriacetate (Fe-NTA) damages DNA of human colon cells in different stages of malignant transformation. Opposed to this, little is known on systemic effects of iron and it is still difficult to determine the border between essential iron supplementation and iron overload in humans. The aim of this study was to determine whether Fe-NTA causes global and specific DNA damage in peripheral leucocytes. Human leucocytes were treated in vitro with Fe-NTA for 30 min at 37 degrees C. Male Sprague Dawley rats were fed (6 weeks) with an iron-overload diet (9.9 g Fe/kg DM) and whole blood was collected. DNA damage was measured in human and rat blood cells using the alkaline version of the Comet Assay with repair specific enzymes. In human cells the distribution of TP53 in the comet images was detected using fluorescence in situ hybridization (Comet FISH) to measure DNA damage in the region of the TP53 gene. Fe-NTA (10-500 microM) was clearly genotoxic in human leucocytes in vitro, and also in leucocytes of rats fed the iron overload diet. The induced damage in human leucocytes was approximately two-fold that observed previously in human colon cells. Oxidized bases were induced by iron in rat leucocytes in vivo, while they were not induced in human leucocytes in vitro. Fe-NTA enhanced the migration of TP53 signals into the comet tail of human leucocytes, indicating a high susceptibility of this tumour-relevant gene towards DNA damage induced by iron overload. In conclusion, iron markedly induced DNA damage in human and rat leucocytes, which shows that these white blood cells are sufficiently sensitive to assess exposure to iron. The measurement of DNA damage in human leucocytes could be used as a sensitive biomarker to study iron overload in vivo in humans and thus to determine whether supplementation results in genotoxic risk.

Antimutagenic effect of polysaccharide ginsan extracted from Panax ginseng

Ginsan is a polysaccharide extracted from the roots of Panax ginseng, and it has earlier been reported to have an immunostimulatory effect. In the present study, the frequency of micronucleated polychromatic erythrocytes (MNPCE) was assessed in the bone marrow of C57BL/6 male mice treated with ginsan [100, 200 or 300 mg/kg body weight (b.w.)] or amifostine (200mg/kg b.w.) 30 min before as well as 15 min after 1.5 Gy of gamma-irradiation. Ginsan and amifostine did not alter the frequency of MNPCE of control mice (P>0.05), showing that they are non-mutagenic per se; gamma-irradiation induced a statistically significant (P<0.001) increase of MNPCE and decrease of PCE/NCE ratio (P<0.001) compared to control group. However, ginsan applied 30 min before or 15 min after irradiation reduced MNPCE in a dose-dependent manner. Amifostine (200mg/kg b.w.) did not reduce radiation-induced MNPCE, but stimulated erythropoiesis, when administered before irradiation. Based on the above results, radioprotective effect of ginsan can be partially attributed to reduction of radiation-induced genotoxicity.

Modified 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (abts) method to measure antioxidant capacity of Selected small fruits and comparison to ferric reducing antioxidant power (FRAP) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) methods

The measurement of antioxidant capacity in fruits differs from that of other biological samples due to their low pH and very low lipophilic antioxidant capacity. In this report, we present a modified 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method for fruits and compare its performance with the other commonly used antioxidant methods of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The antioxidant capacity and reaction kinetics of four phenolic compounds, two antioxidant standards, and five fruits were also investigated. The modified ABTS method prepared at a pH of 4.5 with sodium acetate buffer is highly stable and easily applied to fruit samples as compared to the standard (pH 7.4) version. The measured antioxidant capacity of samples varied with the assay method used, pH, and time of reaction. Traditional antioxidant standards (trolox, ascorbic acid) displayed stable, simple reaction kinetics, which allowed end point analysis with all of assays. Of the phenolic compounds examined, chlorogenic and caffeic acids exhibited the most complex reaction kinetics and reaction rates that precluded end point analysis while gallic acid and quercetin reached stable end points. All fruit extracts exhibited complex and varied kinetics and required long reaction times to approach an end point. Because the antioxidant capacity of fruit extracts is a function of the array of individual antioxidants present, accurate comparisons among fruit samples require that reaction times be standardized and of sufficient length to reach steady state conditions and that more than one assay be used to describe the total antioxidant activity of fruit samples.

Antioxidant activity of Crataegus aronia aqueous extract used in traditional Arab medicine in Israel

BACKGROUND

The medicinal use of extracts prepared from plant parts of the genus Crataegus dates back to ancient times. Furthermore, it has been proposed that its antioxidant constituents account for its beneficial therapeutic effects. A decoction of leaves and unripe fruits from Crataegus aronia syn. azarolus (L) (Rosaceae), the indigenous Israeli hawthorn, is used to treat cardiovascular diseases, cancer, diabetes and sexual weakness in Arab traditional medicine.

PURPOSE

Because laboratory data on the bioactivity of extracts prepared from the indigenous Israeli hawthorn is lacking, we evaluated the antioxidant and cytotoxic potentials of an extract prepared from leaves and unripe fruits in a variety of cell and cell-free in vitro assays.

METHODS

The antioxidant assays measured: (a) its ability to inhibit (i) oxidation of beta-carotene, (ii) 2,2'-azobis(2-amidino-propan) dihydrochloride (AAPH)-induced plasma oxidation and (iii) iron-induced lipid peroxidation in rat liver homogenates; (b) its ability to scavenge the superoxide (O2-) radical; (c) its effects on the enzyme xanthine oxidase (XO) activity; (d) its effect on the redox state of glutathione (GSH) in cultured Hep G2 cells. In addition, we also evaluated the effects of the extract on cell membrane integrity and mitochondrial respiration in cultured Hep G2 cells.

RESULTS AND CONCLUSIONS

Water-soluble extracts inhibited (1) oxidation of beta-carotene, (2) AAPH-induced plasma oxidation and (3) Fe(2+)-induced lipid peroxidation in rat liver homogenates. In addition, the extract (4) is an efficient scavenger of the O2- (5) increases intracellular GSH levels and (6) is not cytotoxic. Accordingly, we propose that the therapeutic benefit of Crataegus aronia can be, at least in part, attributed to its effective inhibition of oxidative processes, efficient scavenging of O2- and possible increasing GSH biosynthesis.

The main catechin of green tea, (-)-epigallocatechin-3-gallate (EGCG), reduces bleomycin-induced DNA damage in human leucocytes

Interest in the beneficial effects of green tea has led to investigations on activities by the main catechin (-)-epigallocatechin-3-gallate (EGCG). This antioxidative compound could contribute to cancer chemoprevention by acting antigenotoxic. To further explore this hypothesis we investigated antigenotoxic potentials of low EGCG concentrations in human peripheral leucocytes. Leucocytes isolated from whole blood were (1) stimulated with phytohaemagglutinin, (2) damaged with genotoxic bleomycin, and (3) post-incubated to allow DNA repair. After each phase DNA integrity was measured with the comet assay. EGCG (2, 20, 100 microM) was added either during phases 1, 2 or 3 or during the whole process (1-3), to delineate mechanisms of antigenotoxicity reflecting induction of detoxification (phase 1), scavenging of radicals (phase 2), stimulation of repair (phase 3), respectively. Bleomycin induced breaks and endonuclease III specific damage, but EGCG did not affect damage or repair of these lesions when added during phases 1, 2 or 3. However, the application of EGCG during phases 1 and 2 significantly reduced both bleomycin-induced breaks and endonuclease III sensitive sites. EGCG added during all phases impaired persistence of damage. Our studies show that the continuous presence of EGCG can reduce radical-induced DNA damage in primary leucocytes, possibly due to a combination of different mechanisms. Together the findings support the hypotheses that EGCG acts protective in human cells.

Which polyphenolic compounds contribute to the total antioxidant activities of apple?

The antioxidant activities of eight apple cultivars were studied by using the ferric reducing/antioxidant power (FRAP), the beta-carotene-linoleic acid model system (beta-CLAMS), and the photochemiluminescent (PCL) assays. The antioxidant activity of apples is highly correlated to the total phenolic content (TPC) measured by the Folin-Ciocalteu method and the total polyphenolic index (TPI) obtained by HPLC. Extracts of the peel and flesh were analyzed and assayed separately. The FRAP activities of both peel and flesh extracts correlate well with the TPC (r = 0.95 and 0.99, respectively) and the TPI (r = 0.82 and 0.99, respectively). Similar results were found in the beta-CLAMS activities, showing correlation coefficients of r = 0.90 and 0.91 with the TPC for the peel and flesh extracts and of r = 0.90 and 0.84 with the TPI for the peel and flesh extracts, respectively. The antioxidant activity measured by the PCL assay was not correlated with TPC or TPI due to the lack of integratable lag phase in this method with the flavan-3-ols/procyanidins. Among the five major polyphenolic groups, flavan-3-ols/procyanidins had the highest positive correlation with the FRAP and beta-CLAMS activities: r = 0.84 and 0.88 for the peel extracts, respectively; and r = 0.98 and 0.87 for the flesh extracts, respectively. At individual compound level, epicatechin and procyanidin B2 were the major contributors to the antioxidant activity of apple. Hydroxycinnamic acids may have a significant role in the flesh.

Butyrate may enhance toxicological defence in primary, adenoma and tumor human colon cells by favourably modulating expression of glutathione S-transferases genes, an approach in nutrigenomics

Butyrate, formed by bacterial fermentation of plant foods, has been suggested to reduce colon cancer risks by suppressing the proliferation of tumor cells. In addition, butyrate has been shown to induce glutathione S-transferases (GSTs) in tumor cell lines, which may contribute to the detoxification of dietary carcinogens. We hypothesize that butyrate also affects biotransformation in non-transformed colon cells. Thus, we have investigated the gene expression of drug metabolism genes in primary human colon tissue, premalignant LT97 adenoma and HT29 tumor cells cultured in an appropriate medium+/-butyrate. A total of 96 drug metabolism genes (including 12 GSTs) spotted on cDNA macroarrays (Superarray; n = 3) were hybridized with biotin-labeled cDNA probes. To validate the expression detected with Superarray, samples of LT97 cells were also analyzed with high density microarrays (Affymetrix U133A), which include biotransformation genes that overlap with the set of genes represented on the Superarray. Relative expression levels were compared across colon samples and for each colon sample+/-butyrate. Compared with fresh tissue, 13 genes were downregulated in primary cells cultivated ex vivo, whereas 8 genes were upregulated. Several genes were less expressed in LT97 (40 genes) or in HT29 (41 and 17 genes, grown for 72 and 48 h, respectively) compared with primary colon tissue. Butyrate induced GSTP1, GSTM2, and GSTA4 in HT29 as previously confirmed by other methods (northern blot/qPCR). We detected an upregulation of GSTs (GSTA2, GSTT2) that are known to be involved in the defence against oxidative stress in primary cells upon incubation with butyrate. The changes in expression detected in LT97 by Superarray and Affymetrix were similar, confirming the validity of the results. We conclude that low GST expression levels were favourably altered by butyrate. An induction of the toxicological defence system possibly contributes to reported chemopreventive properties of butyrate, a product of dietary fibre fermentation in the gut.

Fenvalerate-induced oxidative damage in rat tissues and its attenuation by dietary sesame oil

The primary objective of this study was to investigate the propensity of Fenvalerate (FEN), a synthetic pyrethroid to induce oxidative stress (OS) in various tissues of growing male rats following a short-term (28 days) dietary regimen and its possible attenuation by dietary (10%) sesame oil (SO). FEN incorporated diet was fed to weanling male rats at the dosages of 0, 250, 500 and 1000 ppm. Terminally, significant induction of OS in liver, thymus, spleen and erythrocytes was noticed at higher doses as evidenced by the elevated levels of lipid peroxidation (LPO). Significant dose-dependent depletion of GSH levels, perturbations in antioxidant enzymes, and enhanced protein carbonyls further confirmed the potential of FEN to induce OS in hepatic tissue. In addition, FEN also caused significant increases in activities of hepatic transaminases, ALP and LDH. Interestingly, dietary SO significantly attenuated FEN-induced oxidative damage in liver and other tissues. The degree of protection was remarkably high, since LPO and GSH status, protein carbonyl content and antioxidant defenses in liver and other tissues were brought down to basal levels in the SO + FEN1ooo group. These results clearly indicate the potential of FEN to induce oxidative damage in vivo and also suggest the ability of SO, a dietary fat to significantly offset the oxidative damage which may related to the presence of antioxidant compounds in the oil.

Extract of Toxicodendron quercifolium caused genotoxicity and antigenotoxicity in bone marrow cells of CD1 mice

As has been shown in numerous studies, naturally occurring compounds can have protective effects towards mutagens and carcinogens. In the present study, the genotoxic/antigenotoxic effect of Toxicodendron quercifolium (poison ivy) extract, which has been identified as antigenotoxic in human HepG2 cells in former studies, was examined in the in vivo micronucleus assay using polychromatic erythrocytes (PCE) of bone marrow of CD1-mice. For this, D0 (1:10), D0 (1:25), D0 (1:50), D1 (1:50), D2 (1:50), and D4 (1:50) dilutions of ethanolic plant extract prepared on the basis of the "Hömoopathisches Arzneimittelbuch (HAB 2000)" were administered orally to CD1 mice over a period of two days. A significant increase (p < 0.05) in micronucleus frequencies was found after administration of D0 (1:10), the highest tolerated dose. Additionally, antigenotoxic effects of T. quercifolium towards benzo(a)pyrene-induced micronucleus formation were studied. For that, four dilutions of the plant extract [D0, D2, D4, D6, each 1:50] were administered orally to CD1 mice for five days prior to the administration of benzo(a)pyrene (250 mg/kg b.w.) for another two days. It was found that the administration of the dilutions D0 (1:50) and D2 (1:50) of T. quercifolium extract significantly inhibited benzo(a)pyrene-induced micronucleus formation (p < 0.0001). The results of this study indicated that T. quercifolium extract has the character of a so-called "Janus"-genotoxin: High doses led to a weak but significant increase of micronucleus frequencies whereas low doses showed chemopreventive effects towards benzo(a)pyrene-induced DNA damage. The constituents of T. quercifolium responsible for the genotoxic and antigenotoxic effects may be flavonoids, which are known to have prooxidative and scavenging effects and identified by HPLC-MS/MS.

Assessment of the efficacy of functional food ingredients-introducing the concept "kinetics of biomarkers"

Functional foods are "foods and beverages with claimed health benefits based on scientific evidence". Health claims need to be substantiated scientifically. The future of functional foods will heavily rely on proven efficacy in well-controlled intervention studies with human volunteers. In order to have the maximum output of human trials, improvements are needed with respect to study design and optimization of study protocols. Efficacy at realistic intake levels needs to be established in studies with humans via the use of suitable biomarkers, unless the endpoint can be measured directly. The human body is able to deal with chemical entities irrespective of their origin, and the pharmaceutical terms "absorption, distribution, metabolism and excretion" have their equivalent when biomarkers are concerned. Whereas only "diurnal variation" or "circadian rhythm" is sometimes considered, little attention is paid to "kinetics of biomarkers". "Kinetics of biomarkers" comprises "formation, distribution, metabolism and excretion". However, this is at present neither an established science nor common practice in nutrition research on functional foods. As a consequence, sampling times and matrices, for example, are chosen on the basis of historical practice and convenience (for volunteers and scientists) but not on the basis of in depth insight. The concept of kinetics of biomarkers is illustrated by a variety of readily comprehensible examples, such as malaria, cholesterol, polyphenols, glutathione-S-transferase alpha, F2-isoprostanes, interleukin-6, and plasma triacylglycerides.

The grape and wine polyphenol piceatannol is a potent inducer of apoptosis in human SK-Mel-28 melanoma cells

BACKGROUND & AIM

The resveratrol analogue piceatannol (3,5,3',4'-tetrahydroxy- trans-stilbene; PICE) is a polyphenol present in grapes and wine. PICE is a protein kinase inhibitor that modifies multiple cellular targets exerting immunosuppressive, antileukemic and antitumorigenic activities in several cell lines and animal models. The present work aims to evaluate the antimelanoma effect of PICE on human melanoma cells for the first time. To this purpose, the pro-apoptotic capacity, uptake and metabolism of PICE as well as its effect on cell cycle and cyclins A, E and B1 expression will be studied.

METHODS

. Human SK-Mel-28 melanoma cells were incubated with PICE (1-200 microM) for 72 hours. Cell cycle and viability were examined using flow cytometry analysis. Apoptosis was determined using the annexin V assay and also by fluorescence microscopy. Cyclins A, E and B1 were detected by Western blotting. Stability, cellular uptake and metabolism of PICE were evaluated using HPLC-DAD-MS-MS.

RESULTS

The lowest PICE concentration assayed (1 microM) increased about 6-fold over the control the apoptotic population of melanoma cells (10.2% at 8 hours which remained constant during 48 h). 100 microM PICE induced 13% apoptosis at 8 h increasing up to 41.5% at 48 h. The decrease in cell viability was highly correlated with the increase of apoptotic cells ( R = 0.996; P < 0.0001) revealing that significant cytotoxic, unspecific effects did not occur in melanoma cells upon incubation with PICE. Cell cycle was arrested at G(2) phase which was supported by the down-regulation of cyclins A, E and B1. Two methyl-PICE derived metabolites, 3,5,4'-trihydroxy-3'-methoxy- trans-stilbene and 3,5,3'-trihydroxy-4'-methoxy- trans-stilbene (corresponding to 36% of the initially PICE added) were excreted by cells to the medium. The same methyl-PICE derivatives were also found inside the cells (0.01% of the initially PICE added; 0.0183 picograms/cell).

CONCLUSION

The antimelanoma properties of dietary piceatannol cannot be ruled out taking into account its fast and potent pro-apoptotic capacity at low concentration (1 microM).