Photochemiluminescent detection of antiradical activity: II. Testing of nonenzymic water-soluble antioxidants

Evaluation of antioxidant status and lipid peroxidation in dogs with myxomatous mitral valve degeneration stage B1

Myxomatous mitral valve degeneration (MMVD) is the most common naturally occurring heart disease in dogs. There is a lack of data on antioxidant status and oxidative damage in dogs with MMVD stage B1 according to the American College of Veterinary Internal Medicine (ACVIM B1). The aim of this study was to investigate antioxidant status (plasma vitamin E, lipid-standardized vitamin E (LS-VitE), antioxidant capacity of lipid-(ACL) and water-soluble antioxidants, whole blood glutathione peroxidase and erythrocyte superoxide dismutase), and lipid peroxidation [malondialdehyde (MDA)] in dogs with MMVD ACVIM B1. Serum cholesterol and triglyceride concentrations were measured to calculate LS-VitE. Fourteen dogs with MMVD ACVIM B1 and 12 control dogs were included in the study. Dogs with MMVD had significantly higher vitamin E, ACL, MDA, and cholesterol concentrations and significantly higher LS-VitE values than control dogs. No significant correlations between MDA and antioxidant parameters were determined in either group. In conclusion, oxidative damage to lipids is already present and the antioxidant status is altered but not depleted in dogs with MMVD ACVIM B1. The antioxidant response to increased oxidative damage consists mainly of the activation of fat-soluble antioxidants. Further research is needed to evaluate the efficacy and targets of early antioxidant supplementation to prevent or ameliorate oxidative stress and mitigate disease progression in dogs with early-stage MMVD.

Comprehensive Characterization of Chemical Composition and Antioxidant Activity of Lignan-Rich Coniferous Knotwood Extractives

A knotwood of coniferous trees containing large amounts of polyphenolic extractives is considered a promising industrial-scale source of lignans possessing antioxidant properties and other bioactivities. The present study is aimed at a detailed characterization of the chemical composition and antioxidant activity of lignan-rich extractives obtained from the knotwood of the Norway spruce, Scotch pine, Siberian fir, and Siberian larch growing in the European North of Russia as a region with a highly developed forest industry. To achieve this, a comprehensive approach based on a combination of two-dimensional NMR spectroscopy with high-performance liquid chromatography-high-resolution Orbitrap mass spectrometry, and the determination of antioxidant activity by the three complementary methods were proposed. The studied knotwood samples contained from 3.9 to 17% of extractive substances and were comparable to Trolox's antioxidant activity in the single-electron transfer processes and superoxide radical scavenging, which is associated with the predominance of polyphenolic compounds. The latter was represented by 12 tentatively identified monolignans and 27 oligolignans containing 3-5 phenylpropane units in their structure. The extracts were characterized by an identical set of lignans and differed only in the ratios of their individual compounds. Other components of the knotwood were flavonoids taxifolin, quercetin (Siberian larch), and three stilbenes (pinosylvin, its methyl ester, and pterostilbene), which were identified in the Scotch pine extractives. Sesquiterpene juvabione and its derivatives were found in extracts of Siberian larch knotwood.

In silico study of natural antioxidants

Antioxidants are the body's defense system against the damage of reactive oxygen species, which are usually produced in the body through various physiological processes. There are various sources of these antioxidants such as endogenous antioxidants in the body and exogenous food sources. This chapter provides important information on methods used to investigate antioxidant activity and sources of plant antioxidants. Over the past two decades, numerous studies have demonstrated the importance of in silico research in the development of novel natural and synthesized antioxidants. In silico methods such as quantitative structure-activity relationships (QSAR), pharmacophore, docking, and virtual screenings are play critical roles in designing effective antioxidants that may be synthesized and tested later. This chapter introduces the available in silico approaches for different classes of antioxidants. Many successful applications of in silico methods in the development and design of novel antioxidants are thoroughly discussed. The QSAR, pharmacophore, molecular docking techniques, and virtual screenings process summarized here would help readers to find out the proper mechanism for the interaction between the free radicals and antioxidant compounds. Furthermore, this chapter focuses on introducing new QSAR models in combination with other in silico methods to predict antioxidants activity and design more active antioxidants. In silico studies are essential to explore largely unknown plant tissue, food sources for antioxidant synthesis, as well as saving time and money in such studies.

Bisoactive metabolite profile and antioxidant properties of brown juice, a processed Alfalfa (Medicago sativa) by-product

Recently, leaf protein concentrate (LPC) has gained increased attention in response to the constantly growing protein demand. Green biorefineries can become more economical by valorizing their by-products and reducing environmental risks. The current study describes the variations in the antioxidant capacity and phytochemical composition of a liquid by-product (referred to as brown juice (BJ)) obtained during the extraction of leaf protein concentrate (LPC) from the fresh biomass of alfalfa (Medicago sativa L.). Four varieties of alfalfa were investigated during three harvest times, i.e., August 2017 (first harvest), September 2017 (second harvest), and June 2018 (third harvest). Also, the fresh BJ was lacto-fermented to extend its preservation period but also modifying its composition. The results of different general phytochemical composition analyses and antioxidant assays revealed similar tendencies across different alfalfa varieties and harvest times. Most of the phytochemicals in the BJ identified by HPLC-MS/MS can be classified as flavonoids/flavonoid derivatives, e.g., apigenin, naringenin, luteolin, formononetin. Substantially, the lacto-fermentation process induced a switch into aglycones, e.g., apigenin content increased by an order of magnitude, while apigenin-7-O-glucuronide content was halved after lacto-fermentation. Additionally, several B vitamins were detected, including B2, B3, and B7. These results could provide a basis for various ways of industrial valorization but need to be strengthened by data generated from large-scale production.

A mini-review of the effects of inhalational and intravenous anesthetics on oxidative stress in dogs

General anesthesia increases the production of reactive oxygen species (ROS), which can exacerbate or increase oxidative stress and thus affect the prognosis of surgical procedures. Oxidative stress has been implicated in the development of cardiovascular, dermatologic, oncologic, and other diseases in dogs, as well as ischemia and reperfusion injury. Some anesthetics, such as halogenated anesthetics, have been shown to stimulate the production of ROS, while others, such as propofol, have antioxidant properties. However, the antioxidant effects of these anesthetics may not be sufficient to counteract oxidative damage at the doses used clinically. Nevertheless, the effects of anesthetics should be considered to minimize oxidative damage during anesthesia in dogs to improve the outcome of procedures requiring general anesthesia. This mini-review addresses the current knowledge on oxidative stress during inhalational and intravenous anesthesia in dogs. There is still a lack of information on the management of anesthesia in dogs with respect to oxidative stress. Further research, including comprehensive clinical studies is needed to better understand oxidative injury mechanisms and improve perioperative protocols during anesthesia in dogs.

Comparative life cycle assessment of a mesh ultra-thin layer photobioreactor and a tubular glass photobioreactor for the production of bioactive algae extracts

This study aimed at the comparison of two different photobioreactors with focus on technology and sustainability. The mesh ultra-thin layer photobioreactor (MUTL-PBR) exhibited around 3-fold biomass based space-time-yield and an around 10-fold specific antioxidant capacity than the traditional reference photobioreactor. Life cycle assessment (LCA) was done under autotrophic conditions in both pilot scale reactors with focus on biomass production and on antioxidant capacity of the biomass, respectively. Biomass production within the reference reactor showed a lower environmental impact in most categories. A significantly higher energy demand for mixing and cooling of the cell suspension within the MUTL-PBR is the major reason for its environmental burden. This relates to high impacts in the categories "non-renewable energy" and "global warming potential" per kg biomass. Comparing algal antioxidant capacity, environmental impact of the MUTL cultivation was 5-10 times lower. This clearly illustrates the potential of MUTL-PBR for sustainable production of bioactive substances.

Antioxidant capacity of lipid- and water-soluble antioxidants in dogs with subclinical myxomatous mitral valve degeneration anaesthetised with propofol or sevoflurane

Background

Antioxidants located in both the hydrophilic and lipophilic compartments of plasma act as a defence system against reactive oxygen species (ROS). Excessive production of ROS during anaesthesia affects the antioxidant capacity of plasma and may result in oxidative stress. The aim of this study was to evaluate the antioxidant capacity of lipid- (ACL) and water-soluble (ACW) antioxidants in client-owned dogs diagnosed with periodontal disease and early-stage myxomatous mitral valve degeneration (MMVD) and anaesthetised for a dental procedure with propofol and sevoflurane or with propofol only.

Results

Dogs with MMVD were anaesthetised with propofol and sevoflurane (MMVD/PS, n = 8) or with propofol only (MMVD/P, n = 10). Dogs with no evidence of MMVD (PS, n = 12) were anaesthetised with propofol and sevoflurane. Blood samples for determination of ACL and ACW were collected before and 5 min, 60 min and 6 h after induction to anaesthesia. In MMVD/PS dogs, ACL was significantly higher at all sampling times when compared to PS dogs. Compared to basal values, only anaesthesia maintained with propofol significantly increased ACL at 60 min in dogs with MMVD. In MMVD/P dogs, ACW increased after induction to anaesthesia and remained elevated up to 6 h after anaesthesia. Compared to basal values, anaesthesia maintained with sevoflurane significantly increased ACW only at 60 min in both dogs with and without MMVD. The only difference between propofol and propofol/sevoflurane anaesthesia in dogs with MMVD was significantly higher ACW at 60 min after induction to anaesthesia in the propofol group.

Conclusions

Regarding antioxidant capacity, propofol could be a better choice than sevoflurane for anaesthesia of dogs with early-stage MMVD, although further studies are necessary to clarify the advantage of this antioxidant capacity.

Effect of Anthocyanin-Rich Tart Cherry Extract on Inflammatory Mediators and Adipokines Involved in Type 2 Diabetes in a High Fat Diet Induced Obesity Mouse Model

Male C57BL/6J mice were used to determine the possible therapeutic effects of our previously described tart cherry extract in a chronic obesity mouse model on metabolic parameters, glucose tolerance, inflammatory mediators, and antioxidant capacity. The control group received standard mouse chow, and the high fat control group was switched to a high fat diet and tap water supplemented with 5% sucrose. The high fat + anthocyanin group received the high fat and sucrose diet, but received the anthocyanin-rich tart cherry extract dissolved in their drinking water. After six weeks, an oral glucose tolerance test was performed, and the water-soluble antioxidant capacity (ACW), superoxide dismutase (SOD) activity, and the plasma levels of insulin, C-peptide, leptin, IL-6, MCP-1, adiponectin and resistin were measured. The high fat diet increased body weight, reduced glucose tolerance, and caused an elevation in leptin, IL-6, MCP-1, and resistin levels. Furthermore, antioxidant capacity was decreased with a significant elevation of SOD activity. Anthocyanin treatment failed to reverse the effects of the high fat diet on body weight and glucose tolerance, but significantly reduced the leptin and IL-6 levels. The tart cherry extract also made a significant enhancement in antioxidant capacity and SOD activity. Our results show that chronic anthocyanin intake has a potential to enhance redox status and alleviate inflammation associated with obesity.

Natural antioxidants of plant origin

Interest in the content of natural antioxidants in plant-based foods can be from the human health perspective, in terms of how these compounds might help promote one's health and wellness, or from the storage point-of-view, as the endogenous antioxidant constituents aid to extend a foodstuff's shelf-life. This chapter reports essential information about the mechanism of antioxidant action and methods employed for determination of their activity, classes of phenolic compounds (phenolic acids, flavonoids, lignans, stilbenes, tannins), sources of plant antioxidants (oil seeds, cereals, legumes, plants of the Lamiaceae family, tea and coffee, tree nuts, fruits, and berries), extraction strategies of phenolic compounds from plant material, and the influence of processing and storage on the content of natural antioxidants in foods and their antioxidant activity. Thermal processing, if not releasing bound phenolics from the structural matrices of the food, tends to decrease the antioxidant potential or, in the best case scenario, has no significant negative impact. Gentler sterilization processes such as high-pressure processing tend to better retain the antioxidant potential of a foodstuff than thermal treatments such as steaming, boiling, or frying. The impact of processing can be assessed by determining the antioxidant potential of foodstuffs either at the point of formulation or after different periods of storage under specified conditions.

Determination of Flavonoid and Proanthocyanidin Profile of Hungarian Sour Cherry

Hungarian sour cherries (SC) are excellent source of anthocyanin (concentrations (100–300 mg in 100 g fresh fruit) and melatonin (0.15 mg in 100 g fresh fruit), but other flavonoid derivatives also can be isolated by aqueous alcoholic extraction. We have developed a new process for extracting non-extractable procyanidines bound to the membrane, proteins, and fibers. These compounds were seperated with UHPLC-MS methods, and the structure of individual components were identified on the basis of their mass fragmentation spectra. The antioxidant capacity of soluble and non-soluble antioxidants were measured with ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (DPPH), trolox equivalent antioxidant capacity (TEAC) assays, and compared to the new measurement methods of water-soluble antioxidant capacity (ACW), lipid-soluble antioxidant capacity (ACL). Furthermore, total phenolic content (TPC) and total procyanidin content (PAC) were determinated. As a result of our investigation, we found that the solvent combination, where in the first step is water–ethanol (1:1), then 100% ethanol were suitable for the extraction of the extractable antioxidants. However, the chemiluminescence method that is based on the elimination of the superoxide radical is more accurate than other colorimetric methods which measure antioxidant capacity.

Control of cell morphology of probiotic Lactobacillus acidophilus for enhanced cell stability during industrial processing

The viability of bacteria during industrial processing is an essential quality criterion for bacterial preparations, such as probiotics and starter cultures. Therefore, producing stable microbial cultures during proliferation is of great interest. A strong correlation between the culture medium and cellular morphology was observed for the lactic acid bacterium Lactobacillus acidophilus NCFM, which is commonly used in the dairy industry as a probiotic supplement and as a starter culture. The cell shapes ranged from single short rods to long filamentous rods. The culture medium composition could control this phenomenon of pleomorphism, especially the use of peptone in combination with an adequate heating of the medium during preparation. Furthermore, we observed a correlation between the cell size and stability of the microorganisms during industrial processing steps, such as freeze-drying, extrusion encapsulation and storage following dried preparations. The results revealed that short cells are more stable than long cells during each of the industrially relevant processing steps. As demonstrated for L. acidophilus NCFM, the adaptation of the medium composition and optimized medium preparation offer the possibility to increase the concentration of viable cells during up- and survival rate during down-stream processing.

Use of photochemiluminescence for the determination of antioxidant activities of carotenoids and antioxidant capacities of selected tomato products

The purpose of this study was to compare the antioxidant activity of carotenoids to that of α-tocopherol by using a photochemiluminescence method (PCL). Comparisons to results obtained by using other established methods (α-TEAC, FRAP, DPPH, LPSC) were carried out. A relationship between the chemical structure of carotenoids and their antioxidant activity could be discussed. The number of conjugated double bonds and functional groups had a positive influence. Additionally, the lipophilic antioxidant capacities of selected tomato products were analyzed using PCL and α-TEAC. HPLC was used to identify and quantify contents of carotenoids, tocopherols, and tocotrienols. The raw material fresh tomatoes had the lowest antioxidant effect in both assays due to the lower carotenoid content. Tomato ketchup had the highest AOC in PCL, and tomato puree, in α-TEAC. The antioxidant capacities were mainly dependent on the water content of the samples. Furthermore, a concentration-dependent effect could be observed in both assays.

Comparison of the antioxidant potential in urine, saliva and skin

AIM

Free radicals, oxidative stress and their possible consequences for health are becoming increasingly important in modern medicine. Reactive species influence the organism, potentially causing oxidative cell damage. They can be produced by exogenous sources, or be a product of a variety of not only physiological metabolic processes, such as immune response, but also pathological processes. The antioxidant protection system protects the organism from oxidative damage caused by reactions producing an excess of free radicals. The analysis of antioxidant potential (AOP) is therefore becoming increasingly important for the diagnosis of individual vitality.

METHOD

The photochemoluminescence method was used to measure the AOP in urine and saliva, spectrometry was employed to measure the β-carotene content of the skin. In addition, it was investigated whether the AOP(saliva) correlated with the AOPU(urine) (uric-acid independent AOP) as well as the β-carotene content of the skin.

RESULTS

The AOP was significantly higher in urine than in saliva, and both values were significantly positively correlated with each other. However, there was no significant correlation to the β-carotene content of the skin.

DISCUSSION

The components of the AOPU(urine) are accumulated over time (night), whereas AOP measurement in saliva is like a snapshot, which explains why AOPU(urine) was significantly higher than AOP(saliva), although the two parameters are correlated with each other. β-carotene is a fat-soluble antioxidant, whereas in our study, only water-soluble antioxidants were determined in the urine. This explains why there is no positive correlation between β-carotene of the skin and AOP.

CONCLUSION

For the characterization of the AOP in epidemiological studies, we recommend determining the AOPU(urine) and parallel to this, the β-carotene content of the skin.

Diversity of polyphenol action in Caenorhabditis elegans: between toxicity and longevity

The model organism Caenorhabditis elegans was utilized to determine, in vivo, the mode(s) of action of four plant polyphenols, namely, tannic acid (TA), gallic acid (GA), ellagic acid (EA), and catechin (CT). The determination of lifespan, stress resistance, growth, reproduction, eating-related behaviors, antioxidative capacities, and lifespan assays with the mev-1 and the eat-2 mutants as well as in the presence of dead bacteria provided new insights into their action. All four compounds prolonged lifespan, but only TA and CT mediated distinct stress protection. Longevity is unlikely the result of antioxidant capacities but rather due to calorie restriction imitating and hormetic properties in the case of TA and EA or antimicrobial capacities of GA and EA. Furthermore, the prominent "disposable soma theory" is only partly reflected by these polyphenols. In summary, this study underlines the diversity of polyphenolic phytochemicals and their mechanistic background.

Study of the polyphenolic composition and antioxidant activity of new sherry vinegar-derived products by maceration with fruits

Several experiments of maceration of a sherry wine vinegar with different fruits (orange, lemon, strawberry, grapefruit, and lime) have been carried out. After optimization (only peel, no heating and seven days as maximum time of maceration), parameters such as polyphenolic content, superoxide anion scavenging ability (related to antioxidant activity) and ascorbic acid content were determined in sherry wine vinegars macerated with two amounts of peel and for two maceration times (3 and 7 days). The analysis of variance pointed to a clear relationship (p<0.01) between type of fruit and amount of peel and polyphenolic content. The factor "time" was practically not significant for any polyphenol. Sherry wine vinegars macerated with different fruits exhibited higher superoxide anion scavenger ability, with the maximum values found for the vinegar macerated with lemon peel. The correlation analysis showed that the superoxide anion scavenger ability of the vinegars macerated, and thus their antioxidant activity, was highly correlated (p<0.01) with several polyphenols, especially with naringin, hesperidin, neohesperidin and gentisic acid and not with the ascorbic acid content.

Phytic acid, phytase, minerals, and antioxidant activity in Canadian dry bean ( Phaseolus vulgaris L.) cultivars

Ten bean cultivars grown in southern Manitoba in 2006 were evaluated for variability in phytate, phenolic, and mineral contents, phytase activity, and antioxidant properties to elucidate the relationship of these components. Phytic acid content and phytase activity varied significantly among cultivars and market classes, ranging from 16.7 to 25.1 g/kg and from 224 to 361 phytase activity unit/kg of sample, respectively. The bean cultivars with total phenolic content ranging from 2.2 to 5.6 g of catechin equiv/kg of sample exhibited significant variation in antioxidant capacity [1.6-11.2 microM Trolox equiv (TE)/g of dry matter] and peroxyl radical scavenging activity (72-158 microM TE/g) using photochemiluminescence and fluorescence assays, respectively. Multivariate data analysis performed on 22 components analyzed in this study using principal component analysis and cluster methods demonstrate that differences in phytase, antioxidant activity, mineral contents, and bioavailability are much larger within market class than among bean cultivars.

Antimutagenic in vitro activity of plant polyphenols: Pycnogenol and Ginkgo biloba extract (EGb 761)

Ofloxacin (15 microg/mL) and acridine orange (5 microg/mL) induce mutagenicity by different mechanisms in the photosynthetic flagellate Euglena gracilis. The present study examined whether Pycnogenol (PYC; 5-100 microg/mL) or Ginkgo biloba extract (EGb 761; 5-100 microg/mL) could protect against the mutagenic effects of each of the mutagens and the potential mechanisms underlying such protection. The highest concentration of PYC and EGb 761 effectively reduced the mutagenic activity of both ofloxacin and acridine orange by more than 99% (p < 0.001). Using luminol-dependent photochemical methodology it was demonstrated that EGb 761 and PYC were effective antioxidants. In addition, as determined by spectrophotometry, PYC and EGb 761 bound acridine orange. Both PYC and EGb 761 have been shown to produce dual antimutagenic effects, as evidenced by both antioxidant and physicochemical properties. The findings suggest that EGb 761 and PYC would thus be suitable for future study, not only as antioxidants, but also as antimutagenic agents.

Major phenolic acids and total antioxidant activity in Mamaki leaves, Pipturus albidus

Three phenolic acids, (+)catechins, chlorogenic acid, and rutin, were identified and quantified in Mamaki leaves using a liquid chromatograph-mass spectrometer technique. Concentrations of (+)catechins, chlorogenic acid, and rutin varied from 1.1 to 5.0 mg/g of Mamaki leaves as determined in the extract using 0.5% acetic acid in 90% aqueous methanol. This study also quantified total antioxidant capacity using the photochemiluminescence method, which was expressed in equivalents to ascorbic acid (AA). Mamaki teas brewed for 30 min contained total antioxidant activity (TAA) between 238 and 259 mg AA/g of tea. Mamaki teas brewed for 1 h and stored at 4 h, 1 d, and 3 d at 4 degrees C had available TAA 293, 271, 172, and 163 mg AA/g of tea leaves, respectively. The concentrations of (+)catechins and rutin in Mamaki leaves are compared to other types of popular teas. Mamaki teas contained relatively low amounts of TAA compared to green teas and Lipton teas.

Assessment of the oxidant–antioxidant blood balance in a field exercise test in Standardbredand eventing horses

The aim of this study was to determine which oxidant–antioxidant blood markers are of interest for a field exercise test (ET) performed on a racetrack. Healthy Standardbred horses (S:n= 12) and healthy eventing horses (E:n=12) were investigated. Exercise was monitored by measuring velocity (V), heart rate (HR), and plasma lactate (LA). Whilst maximal LA did not differ (11.8±0.88 mmol l−1), maximalV(S: 12.3±0.17 m s−1versusE: 11.1±0.24 m s−1,P<0.05) and final HR (S: 222±1versusE: 203±8 beats min−1,P<0.05) were significantly different between groups. Venous blood was collected at rest (R) prior to ET and the following oxidant–antioxidant markers were determined: uric acid (UA), ascorbic acid (AA), α-tocopherol (Vit E), vitamin A (Vit A), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione (reduced: GSH and oxidized: GSSG), glutathione redox ratio (GRR), copper (Cu), zinc (Zn) and selenium (Se), oxidized proteins (Protox), lipid peroxides (Pool), antioxidant capacity of water-soluble components (ACW) and antioxidant capacity of lipid-soluble components (ACL). The following markers were further determined 15 min (E15) after the ET: UA, ACW, AA, GSH, Protox, Pool, ACL. Standardbreds had significantly higher concentrations of ACW, GSH, ACL and Protox, whilst Se, Zn and SOD were significantly lower than in eventing horses. Exercise induced a significant increase in ACW and UA. GSH decreased in eventing horses and Pool significantly decreased in both horse groups. This study describes a field ET of high intensity for Standardbred and eventing horses, which could be performed by all animals tested. By sampling blood at rest and at E15, changes of the hydrophilic antioxidant defence were partially assessed, whereas no interpretable changes of the lipophilic antioxidants and of oxidation markers (Protox, Pool) could be detected.

High-amylose corn exhibits better antioxidant activity than typical and waxy genotypes

The consumption of fruits, vegetables, and whole grains rich in antioxidative phytochemicals is associated with a reduced risk of chronic diseases such as cancer, coronary heart disease, diabetes, Alzheimer's disease, cataract, and aged-related functional decline. For example, phenolic acids are among the main antioxidative phytochemicals in grains that have been shown to be beneficial to human health. Corn (Zea mays L.) is a major staple food in several parts of the world; thus, the antioxidant activity of several corn types was evaluated. The 2,2-Diphenyl-1-picryhydrazyl free radical (DPPH*) scavenging activity, total phenolic content (TPC), antioxidant capacity of lipid-soluble substances (ACL), oxygen radical absorbance capacity (ORAC), and phenolic acid compositions of typical and mutant genotypes (typical-1, waxy, typical-2, and high-amylose) were investigated. The DPPH* scavenging activity at 60 min was 34.39-44.51% in methanol extracts and 60.41-67.26% in HCl/methanol (1/99, v/v) extracts of corn. The DPPH* scavenging activity of alkaline hydrolysates of corn ranged from 48.63 to 64.85%. The TPC ranged from 0.67 to 1.02 g and from 0.91 to 2.15 g of ferulic acid equiv/kg of corn in methanol and HCl/methanol extracts, respectively. The TPC of alkaline hydrolysates ranged from 2.74 to 6.27 g of ferulic acid equiv/kg of corn. The ACL values were 0.41-0.80 and 0.84-1.59 g of Trolox equiv/kg of corn in methanol and HCl/methanol extracts, respectively. The ORAC values were 10.57-12.47 and 18.76-24.92 g of Trolox equiv/kg of corn in methanol and HCl/methanol extracts, respectively. ORAC values of alkaline hydrolysates ranged from 42.85 to 68.31 g of Trolox equiv/kg of corn. The composition of phenolic acids in alkaline hydrolysates of corn was p-hydroxybenzoic acid (5.08-10.6 mg/kg), vanillic acid (3.25-14.71 mg/kg), caffeic acid (2.32-25.73 mg/kg), syringic acid (12.37-24.48 mg/kg), p-coumaric acid (97.87-211.03 mg/kg), ferulic acid (1552.48-2969.10 mg/kg), and o-coumaric acid (126.53-575.87 mg/kg). Levels of DPPH* scavenging activity, TPC, ACL, and ORAC in HCl/methanol extracts were obviously higher than those present in methanol extracts. There was no significant loss of antioxidant capacity when corn was dried at relatively high temperatures (65 and 93 degrees C) postharvest as compared to drying at ambient temperatures (27 degrees C). Alkaline hydrolysates showed very high TPC, ACL, and ORAC values when compared to methanol and HCl/methanol extracts. High-amylose corn had a better antioxidant capacity than did typical (nonmutant) corn genotypes.

Antimutagenic, antioxidant and antimicrobial properties of Maytenus krukovii bark

The hydroalcoholic extract of Maytenus krukovii bark was investigated for its in vitro mutageno-protective activities by means of the Ames Salmonella/microsome assay. The extract showed an inhibitory effect in both T98 and T100 strains against the mutagenic activity of promutagen 2-aminoanthracene but was not protective against directly acting mutagens sodium azide and 2-nitrofluorene. When tested as a radical scavenger and antioxidant it produced a dose-dependent inhibition. The extract did not show significant antibacterial properties, and was weakly active against dermatophyte and phytopathogenic fungi, but inhibited the growth of phytopathogen Pithyum ultimum.

Polyphenolic profiles and antioxidant activities of heartnut (Juglans ailanthifolia Var. cordiformis) and Persian walnut (Juglans regia L.)

The polyphenolic compositions of three heartnut (Juglans ailanthifolia var. cordiformis) varieties (Imshu, Campbell CW1, and Campbell CW3) were examined and compared with those of two Persian walnut (Juglans regia L.) varieties (Combe and Lake). The nuts were defatted, extracted, and separated into three different fractions, the free phenolic acid (FPA), acid-hydrolyzable phenolic acid (AHPA), and bound phenolic acid (BPA) fractions. The total phenolic contents (TPCs) in both FPA and AHPA of the Persian walnuts were significantly higher (P < 0.001) than those of the heartnuts, but not in the BPA (P = 0.20). LC-ESI-MS(n)() studies revealed that except for the FPA fraction, the major polyphenolics in both heartnut and Persian walnut were ellagic acid and valoneic acid dilactone. Persian walnuts contained an average of 0.29 and 1.31 mg of ellagic acid/g nut in the 80% methanol extractable fractions FPA and AHPA, respectively. Heartnuts contained an average of 0.16 and 0.60 mg of ellagic acid/g nut in the respective fractions. Bound ellagic acid in the residue was 0.93 and 0.70 mg/g of nut in the Persian walnut and in the heartnut, respectively. Valoneic acid dilactone was tentatively identified and quantified as milligrams of ellagic acid equivalent per gram of nut. These components were found to contribute to the strong total antioxidant activities measured using ferric reducing antioxidant power and photochemiluminescence methods.

Antioxidant properties of wheat as affected by pearling

The effects of pearling on the content of phenolics and antioxidant capacity of two Canadian wheat classes, namely, Canada Western Amber Durum; Triticum turgidum L. var. durum; CWAD) and Canada Western Red Spring; Triticum aestivum L.; CWRS) were examined. The antioxidant activity of wheat phenolics was evaluated using oxygen radical absorbance capacity (ORAC), inhibition of photochemiluminescence (PCL), Rancimat method, inhibition of oxidation of low-density lipoprotein, and DNA. The phenolic composition of wheat extracts was determined using high-performance liquid chromatography. The antioxidant capacity of both pearled grains and byproducts significantly decreased as the degree of pearling increased. Among grains, the unprocessed whole grains demonstrated the highest antioxidant capacity. The byproducts always demonstrated higher antioxidant capacity compared to the pearled grains, regardless of the wheat class. The resultant byproducts from 10-20% pearling possessed the highest antioxidant capacity. Processing of cereals may thus exert a significant effect on their antioxidant activity. The concentration of grain antioxidants is drastically reduced during the refining process. As phenolic compounds are concentrated in the outermost layers, the bran fractions resulting from pearling may be used as a natural source of antioxidants and as value-added products in the preparation of functional food ingredients or for enrichment of certain products.

Importance of insoluble-bound phenolics to antioxidant properties of wheat

Two commercial samples of soft (70% Canadian Eastern soft red spring and 30% Canadian Eastern soft white winter) and hard (90% Canadian western hard red spring and 10% Canadian Eastern hard red winter) wheats were used to obtain different milling fractions. Phenolics extracted belonged to free, soluble esters and insoluble-bound fractions. Soluble esters of phenolics and insoluble-bound phenolics were extracted into diethyl ether after alkaline hydrolysis of samples. The content of phenolics was determined using Folin-Ciocalteu's reagent and expressed as ferulic acid equivalents (FAE). The antioxidant activity of phenolic fractions was evaluated using Trolox equivalent antioxidant capacity, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, reducing power, oxygen radical absorbance capacity, inhibition of oxidation of human low-density lipoprotein cholesterol and DNA, Rancimat, inhibition of photochemilumenescence, and iron(II) chelation activity. The bound phenolic content in the bran fraction was 11.3 +/- 0.13 and 12.2 +/- 0.15 mg FAE/g defatted material for hard and soft wheats, respectively. The corresponding values for flour were 0.33 +/- 0.01 and 0.46 +/- 0.02 mg FAE/g defatted sample. The bound phenolic content of hard and soft whole wheats was 2.1 (+/-0.004 or +/-0.005) mg FAE/g defatted material. The free phenolic content ranged from 0.14 +/- 0.004 to 0.98 +/- 0.05 mg FAE/g defatted milling fractions of hard and soft wheats examined. The contribution of bound phenolics to the total phenolic content was significantly higher than that of free and esterified fractions. In wheat, phenolic compounds were concentrated mainly in the bran tissues. In the numerous in vitro antioxidant assays carried out, the bound phenolic fraction demonstrated a significantly higher antioxidant capacity than free and esterified phenolics. Thus, inclusion of bound phenolics in studies related to quantification and antioxidant activity evaluation of grains and cereals is essential.

Evaluation of the Antioxidant Capacity and Preventive Effects of a Topical Emulsion and Its Vehicle Control on the Skin Response to UV Exposure

Supplying topical exogenous antioxidants to the skin may prevent or minimize free radical-induced damaging. This study determines antioxidative capacity of a topical skin care emulsion (an oil-in-water vitamin E-containing formulation) versus its vehicle on human skin that was exposed to ultraviolet radiation (UVR) by utilizing a photochemiluminescence device and biophysical methods. Ten healthy Caucasians (3 male and 7 female; mean age 47 +/- 10 years) were enrolled. In a randomized and double-blind manner, a pH-balanced vitamin E emulsion or its vehicle control was applied onto predesignated forearm prior to UVR exposure. Thirty minutes after application, these test sites were exposed to a UV light to induce the minimal erythema dose. One untreated site served as a blank control. Visual scoring and instrumental measurements were recorded at baseline and at 24 h and 48 h thereafter. At day 3, after completing instrumental measurements, each test site was stripped three times in a consecutive manner with a proprietary adhesive tape disc. These tapes were quantified for antioxidant capacity using a photochemiluminescence device. Vitamin E emulsion and vehicle control significantly (p < 0.05) suppressed visual scores when compared with blank control at day 2 and day 3 after UV exposure. However, vitamin E emulsion showed significantly (p < 0.05) lower visual scores when compared with vehicle control at day 2 and day 3 after UV exposure.Also,vitamin E emulsion and its vehicle control significantly (p < 0.05) diminished skin color measurement (a*) values when compared with blank control at day 2 and day 3 after UV exposure. At day 2 after UV exposure, only vitamin E emulsion significantly (p < 0.05) reduced skin blood flow volume when compared with blank control. Vitamin E emulsion and its vehicle control showed significant (p < 0.05) reduction of blood flow volume when compared with blank control at day 3 after UV exposure. Vitamin E emulsion and its vehicle control proved effective in preventing induction of erythema and reducing inflammatory damage caused by UV exposure. The effect of vitamin E emulsion exceeded that of an 'active control'.

Standardized methods for the determination of antioxidant capacity and phenolics in foods and dietary supplements

Methods available for the measurement of antioxidant capacity are reviewed, presenting the general chemistry underlying the assays, the types of molecules detected, and the most important advantages and shortcomings of each method. This overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical, and dietary supplement industries. From evaluation of data presented at the First International Congress on Antioxidant Methods in 2004 and in the literature, as well as consideration of potential end uses of antioxidants, it is proposed that procedures and applications for three assays be considered for standardization: the oxygen radical absorbance capacity (ORAC) assay, the Folin-Ciocalteu method, and possibly the Trolox equivalent antioxidant capacity (TEAC) assay. ORAC represent a hydrogen atom transfer (HAT) reaction mechanism, which is most relevant to human biology. The Folin-Ciocalteu method is an electron transfer (ET) based assay and gives reducing capacity, which has normally been expressed as phenolic contents. The TEAC assay represents a second ET-based method. Other assays may need to be considered in the future as more is learned about some of the other radical sources and their importance to human biology.

Effect of oral antioxidant supplementation on blood antioxidant status in trained thoroughbred horses

The oxidant/antioxidant equilibrium of trained thoroughbred horses (n = 40) was assessed on three occasions during a period of three months under field conditions by blood antioxidant markers analysis, i.e. plasma ascorbic acid (AA), plasma antioxidant capacity of water-soluble components (ACW), whole blood (GSH) and oxidised (GSSG) glutathione, plasma alpha-tocopherol and beta-carotene, plasma antioxidant capacity of lipid-soluble components (ACL), red blood cell superoxide dismutase (SOD) and glutathione-peroxidase activity (GPx) and plasma trace-elements, i.e. selenium (Se), copper (Cu), zinc (Zn). A control group of ten horses receiving a placebo and an antioxidant group of 30 horses orally supplemented with an antioxidant mixture were randomly formed. An antioxidant imbalance was observed after three months in the control group, reflected by a significant decrease in GSH, SOD, GPx, Se (P < 0.05) and a significant increase in GSSG (P < 0.05). The antioxidant supplement prevented GPx and Se decrease and significantly increased ACW, alpha-tocopherol, beta-carotene and ACL (P < 0.05). Significant sex- or age-related differences were found for AA, ACW, alpha-tocopherol, SOD, GPx and Se, and there were significant correlations between ACW-AA, ACL-alpha-tocopherol, GPx-Se, CPK-Se, CPK-alpha-tocopherol and CPK-Cu. This field study has shown that trained thoroughbred horses undergo significant changes of several blood antioxidant markers and that oral antioxidant supplementation might partially counterbalance these changes by improving the hydrophilic, lipophilic and enzymatic antioxidant blood capacity.

Photochemiluminescent detection of antiradical activity. VII. Comparison with a modified method of thermo-initiated free radical generation with chemiluminescent detection

The method of photosensitized chemiluminescence (PCL) allows the quantification of water- and lipid-soluble antioxidants and activity of superoxide dismutase (SOD) in the same measuring system. However, it needs a special device, which we have described in a previous paper in this series. Another method suitable for the assay of water- and lipid-soluble antioxidants is the thermo-initiated decay of azo-compounds combined with the measurement of O2 consumption (Niki, 1985; Wayner et al., 1985). Its long duration and the complicated measuring procedure is not acceptable for routine medical applications. We show that a modification using CL detection of free radicals with luminol, has results comparable with PCL for the determination of non-enzymic water- and lipid-soluble antioxidants, SOD activity and oxidative modification of proteins. In contrast to PCL, it is possible to use any luminometer with a heatable measuring cell and to investigate coloured samples. While the new method has an overall higher sensitivity and is scalable to microtitre plates, PCL measurements can be made at different pH. The advantages and analytical information content of certain components of the integral antioxidative capacity of blood plasma are discussed in comparison with other methods.

Antioxidant properties of phenolic compounds from Pelargonium reniforme

Flavonoids and hydrolyzable tannins isolated from Pelargonium reniforme were evaluated for their antioxidant ability using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical generating system and a luminol-dependent chemiluminescence assay. In both assays, the polyphenols tested showed higher radical scavenging activities than the reference antioxidant, ascorbic acid (IC50 2.6-32.9 microM vs 40.9 microM in the DPPH test, and 2-25 times stronger effects in the chemiluminescence assay). A comparison of the flavonoids and the tannins showed that the latter have more potential than the former. Structural requirements for marked antioxidant activities of hydrolyzable tannins were the presence of galloyl and hexahydroxydiphenoyl groups, and apparently carbonyl (ester) functionalities in oxidatively modified dehydrohexa-hydroxydiphenoyl moieties. For flavonoids, it appeared that a catechol (3',4'-dihydroxy) element in the B-ring were important determinants and that O-glycosides were more effective than flavone-based C-glucosyls. Conspicuously, introduction of a galloyl group significantly enhanced their potentials. The demonstrated marked antioxidant effects of the polyphenols provide a clue for beneficial effects of P. reniforme in the treatment of liver disorders among several ethnic groups in areas of southern Africa.

Isoflavone characterization and antioxidant activity of ohio soybeans

Seventeen Ohio soybeans were screened for isoflavone content and antioxidant activity. Isoflavone content was determined by C(18) reversed phase high-performance liquid chromatography coupled with a photodiode array detector. Antioxidant activities of soybean extracts were measured using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical and photochemiluminescence (PCL) methods. The highest and lowest total isoflavone contents were 11.75 and 4.20 micromol/g soy, respectively, while the average was 7.12 micromol/g soy. Antioxidant activities of soybean extracts ranged from 7.51 to 12.18 micromol butylated hydroxytoluene (BHT) equivalent/g soy using the DPPH method. Lipid and water soluble antioxidant activities of soybean extracts ranged from 2.40 to 4.44 micromol Trolox equivalent/g soy and from 174.24 to 430.86 micromol ascorbic acid equivalent/g soy, respectively, using the PCL method.

A rapid, accurate, and facile method to quantify the antioxidative capacity of topical formulations

BACKGROUND/AIMS

Various methodologies have been developed to quantify antioxidant activity. A simple, rapid and accurate method is demanded. This study examined the antioxidative status of a pH balanced vitamin E containing formulation versus its vehicle control utilizing a photochemiluminescence device.

METHODS/RESULTS

A pH balanced 5% Vitamin E containing formulation and its vehicle control were tested. The quantity of antioxidant capacity for the pH balanced vitamin E formulation and its vehicle control were 2.28 +/- 0.05 and 0.16 +/- 0.03, respectively. The pH balanced vitamin E formulation showed a significant (P < 0.001) higher antioxidant capacity compared to its vehicle control.

CONCLUSIONS

This method not only provides quantitative data, but also is rapid, accurate, and facile in performance. The in vitro data obtained in this study require validation by in vivo studies to properly place them in context to alternate methods.

Generation of hydroxyl radicals mediated by streptozotocin in pancreatic islets of mice in vitro

Type I diabetes is considered a multifactorial autoimmune process initiated by an environmental factor. There is evidence that reactive oxygen species are involved in destructing insulin-producing beta-cells. In mice, reactive oxygen species and nitric monoxide contribute to beta-cell damage in the non-obese diabetic strain developing spontaneously diabetes and in diabetes induced with multiple low doses of streptozotocin. Previously, we found that zinc sulfate induced metallothionein in pancreatic islets, protected beta-cells against streptozotocin toxicity in vitro, and prevented diabetes induced with multiple low doses of streptozotocin. Since metallothionein is known to scavenge hydroxyl radicals in cell-free systems, we hypothesize that the protective effect of zinc sulfate results from metallothionein induction scavenging hydroxyl radicals generated by multiple low doses of streptozotocin. Therefore, we studied whether levels of hydroxyl radicals are increased by streptozotocin in isolated islets in vitro. Here, we demonstrate basal and streptozotocin-stimulated hydroxyl radicals by electron spin resonance spectroscopy in combination with hydroxyl radical-specific spin trapping in islet homogenates. Furthermore, in islet cultures, streptozotocin augmented generation of reactive oxygen species as determined by fluorescence. Of the group of reactive oxygen species, the streptozotocin-augmented generation of hydrogen peroxide was also specifically determined. We conclude that streptozotocin-mediated hydroxyl radicals and generation of reactive oxygen species may be crucial effectors in beta-cell damage.

Evaluation of 3-nitrotyrosine as a marker for 3-nitropropionic acid-induced oxidative stress in Lewis and Wistar rats and strain-specific whole brain spheroid cultures

The present study investigated whether 3-nitrotyrosine is an early marker for neurodegenerative processes involving oxidative stress. We characterized the 3-nitrotyrosine formation after 3-nitropropionic acid (3-NP) exposure in the whole brain spheroid culture model and in a rat model, using Lewis and Wistar rats. Increased 3-nitrotyrosine concentration in spheroid cultures from Lewis rats was observed at lower dose of and shorter exposure time to 3-NP as compared to alterations in glial fibrillary acidic protein concentration, decrease in glutamine synthetase activity or cell loss. Five days of exposure to 3-NP (5 mM) resulted in decreased staining of GABAergic processes, while neuronal nitric oxide synthase staining was preserved. In addition, staining of EAAC1, anti-2',3'-cyclic nucleotide 3'-phosphohydrolase and ED1 was diminished after treatment of spheroid cultures with 3-nitropropionic acid (5 mM), while isolectin B4 staining was increased. Dithiothreitol and vitamin E inhibited the increased formation of 3-nitrotyrosine. Interestingly, N(G)-nitro-L-arginine methyl ester increased the 3-nitrotyrosine formation. No increased 3-nitrotyrosine concentration was shown after exposure to 3-nitropropionic acid during 5 days in spheroid cultures obtained from Wistar rats. In the striatum of 3-NP-exposed Lewis and Wistar rats, no change in 3-nitrotyrosine concentration was observed, whereas only in Wistar rats the glial fibrillary acidic protein concentration was increased in addition to activation of microglial cells. It is concluded that 3-nitrotyrosine was a more sensitive marker for oxidative stress-induced neurodegeneration than glial fibrillary acidic protein and glutamine synthase in spheroid cell cultures of Lewis rats. Finally, the similarities between the 3-NP spheroid model and the vivo model indicate that the spheroid cultures provide a good alternative for chronic exposure of animals to neurotoxins.

Amperometric biosensor based on a functionalized gold electrode for the detection of antioxidants

A method for the electrochemical detection of antioxidants has been developed, which is based on a radical measurement with a cytochrome c modified electrode. A controlled enzymatic production system for superoxide radicals based on xanthine oxidase was used. The addition of antioxidants facilitated the decomposition of the radical in addition to the spontaneous dismutation. The steady-state of superoxide generation and decomposition was thus shifted to a new situation due to the higher decomposition rate after antioxidant addition. This resulted in a decreased current level at the electrode. Antioxidant activity could be quantified from the response of the sensor electrode by the percentage of the signal decrease. The 50% inhibition value (IC(50)) for different antioxidants was calculated and the antioxidant activity of numerous substances was compared. Thus, a hierarchy of superoxide radical scavenging abilities of flavonoids was established: flavanols>flavonols>flavones>flavonones>isoflavonones.

Antioxidative and antimutagenic activity of yeast cell wall mannans in vitro

Antioxidative and antimutagenic effect of yeast cell wall mannans, in particular, extracellular glucomannan (EC-GM) and glucomannan (GM-C.u.) both from Candida utilis, mannan from Saccharomyces cerevisiae (M-S.c.) and mannan from Candida albicans (M-C.a.) was evaluated. Luminol-dependent photochemical method using trolox as a standard showed that EC-GM, GM-C.u., M-S.c. and M-C.a. have relatively good antioxidative properties. EC-GM exhibited the highest antioxidative activity, followed by GM-C.u. and M-S.c. M-C.a. showed the least antioxidative activity. These mannans were experimentally confirmed to exhibit different, statistically significant antimutagenic activity in reducing damage of chloroplast DNA of the flagellate Euglena gracilis induced by ofloxacin and acridine orange (AO). We suggest that the antimutagenic effect of EC-GM, GM-C.u., M-S.c. and M-C.a. against ofloxacin is based on their ability to scavenge reactive oxygen radicals. With AO, the reduction of the chloroplast DNA lession could be a result of the absorptive capacity of the mannans. The important characteristics of mannans isolated from the yeast cell walls, such as good water solubility, relatively small molecular weight (15-30kDa), and antimutagenic effect exerted through different mode of action, appear to be a promising features for their prospective use as a natural protective (antimutagenic) agents.

Photochemiluminescent detection of antiradical activity. V. Application in combination with the hydrogen peroxide-initiated chemiluminescence of blood plasma proteins to evaluate antioxidant homeostasis in humans

Disturbance of the steady state between pro- and antioxidants in tissues is an important aetiopathogenetic factor. Two method--(i) photosensitized chemiluminescence for detection of antiradical activity and (ii) hydrogen peroxide-initiated chemiluminescence of plasma proteins (CLP) and erythrocytes (CLE)--were tested in 136 healthy donors and 82 patients with untreated breast tumours for their applicability to detecting disturbances in antioxidant homeostasis in humans. The total antiradical capacity of water-soluble substances (ACW) and its urate-independent proportion (ACU) were lower (P <0.05) and CLP higher (P <0.001) in smokers in comparison to non-smokers. A significant negative correlation was found between the content of ascorbate in plasma and the intensity of CLP: r = -0.39, P <0.001. A significant reduction in ACU and increased values of CLP and CLE were seen according to the stage of disease in breast cancer patients. On the basis of these observations and model experiments we suggest that hydrogen peroxide-initiated chemiluminescence can serve as a parameter of oxidative modification of blood components and, in combination with the antioxidant parameters, can be used to describe the antioxidant homeostasis in humans and possibly to have value as a predictor of disease states.