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Cellular antioxidant activity (CAA) assay for assessing antioxidants, foods, and dietary supplements.

Posted
Authors
Wolfe KL, Liu RH
Journal
J Agric Food Chem 55(22):8896-907
Abstract

A cellular antioxidant activity (CAA) assay for quantifying the antioxidant activity of phytochemicals, food extracts, and dietary supplements has been developed. Dichlorofluorescin is a probe that is trapped within cells and is easily oxidized to fluorescent dichlorofluorescein (DCF). The method measures the ability of compounds to prevent the formation of DCF by 2,2′-azobis(2-amidinopropane)
dihydrochloride (ABAP)-generated peroxyl radicals in human hepatocarcinoma HepG2 cells. The decrease in cellular fluorescence when compared to the control cells indicates the antioxidant capacity of the compounds. The antioxidant activities of selected phytochemicals and fruit extracts were evaluated using the CAA assay, and the results were expressed in micromoles of quercetin equivalents per 100 μmol of phytochemical or micromoles of quercetin equivalents per 100 g of fresh fruit. Quercetin had the highest CAA value, followed by kaempferol, epigallocatechin gallate (EGCG), myricetin, and luteolin among the pure compounds tested. Among the selected fruits tested, blueberry had the highest CAA value, followed by cranberry > apple ) red grape > green grape. The CAA
assay is a more biologically relevant method than the popular chemistry antioxidant activity assays because it accounts for some aspects of uptake, metabolism, and location of antioxidant compounds within cells.

Chitosomes loaded with cranberry proanthocyanidins attenuate the bacterial lipopolysaccharide-induced expression of iNOS and COX-2 in raw 264.7 macrophages

Posted
Authors
Madrigal-Carballo S, Rodriguez G, Sibaja M, Reed JD, Vila AO, Molina F
Journal
J Liposome Res 19(3):189-96
Abstract

Chitosan binds to negatively charged soy lecithin liposomes by an electrostatic interaction driven by its positively charged amino group. This interaction allows stable covered vesicles (chitosomes) to be developed as a suitable targeted carrier and controlled release system. This study investigated the effect of chitosomes on the activation of cranberry proanthocyanidins (PAC) in Raw 264.7 macrophages. Chitosomes were characterized according to size, zeta potential, PAC-loading, and release properties. Results showed an increase in the net positive charge and size of the liposomes as the concentration of chitosan was increased, suggesting an effective covering of the vesicles by means of electrostatic interactions, as shown by transmission electron microscopy and fluorescence microscopy. About 85% of the PAC that was loaded remained in the chitosomes after release studies for 4 hours in phosphate-buffered saline. Cyclo-oxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) are associated with inflammation. Activated RAW 264.7 macrophages increase the expression of COX-2 and iNOS in response to bacterial infection and inflammation; we, therefore, tested the ability of the PAC-loaded chitosomes to attenuate COX-2 and iNOS expression in LPS (lipopolysaccharide)-stimulated macrophages. Increasing the amount of PAC loaded into the chitosomes caused a dose-dependent attenuation of iNOS and COX-2 expression in LPS-stimulated macrophages. A 2% v/v PAC-loaded chitosomes formulation almost completely attenuated the LPS-induced expression of iNOS and COX-2. PAC-loaded chitosomes were more active than PAC alone, suggesting that the macrophage response to LPS occurs after endocytosis of the PAC-loaded chitosomes.

Cranberry derived proanthocyanidins can prevent pathogen invasion of kidney epithelial cells

Posted
Authors
Tufenkji N, Rifai OJ, Harmidy K, Eydelnant IA
Journal
Food Res Int 43 (3):922-924
Abstract

The in vitro effectivity of cranberry derived proanthocyanidins (PACs) for the mitigation of kidney cell
infection by selected uro- and entero-pathogens is examined with an adhesion/invasion assay and confocal
microscopy. This study demonstrates that PACs effectively reduce invasion of canine kidney cells by
pathogenic bacteria: Escherichia coli CFT073 and O157:H7, Enterococcus faecalis 29212, and Pseudomonas
aeruginosa 10145. These effects demonstrate the potential for cranberry derived PACs as a useful tool in
the prevention of kidney infection

Cranberry Juice and Warfarin: When Bad Publicity Trumps Science

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Authors
Zikria J, Goldman R, Ansell J
Journal
Am J Med 123(5):384-92
Abstract

Based on anecdotal reports, the question of whether cranberry juice interacts with warfarin has been raised. This article discusses the potential mechanism, and systematically reviews case reports as well as clinical trials examining the possible interaction. We systematically searched MEDLINE via PubMed, and the Cochrane Library database. Fifteen case reports were summarized, including the initial unpublished brief reports to the Committee on Safety of Medicines and the subsequent 6 published case reports. Seven clinical trials were analyzed, including 3 studies using warfarin and 4 surrogate drugs. Only 2 cases had a validation scale suggesting a "probable" interaction, but even in these patients there were many reasons to question the validity of a relevant drug interaction. Randomized clinical trials and surrogate markers found no evidence to support the interaction between cranberry juice and warfarin. Because the moderate consumption of cranberry juice does not affect anticoagulation, we encourage the reexamination of initial warnings based on scientific evidence. We conclude that the initial precautionary warnings by administrating bodies are limited to anecdotal case reports and represent misleading conclusions.

Cranberry juice inhibits metal and non-metal initiated oxidation of human low density lipoproteins in vitro

Posted
Authors
Wilson T, Porcari JP, Maher MA
Journal
J Nutraceut Function Med Foods 2(2):5-14
Abstract

Flavonoids can bind the divalent cations frequently used to evaluate LDL antioxidant capacity in vitro. Flavonoids in cranberry juice (CBJ) may serve as antioxidants and promote cardiovascular health. This in vitro study characterizes CBJ effects on metal and non-metal based oxidation of human LDL. For cupric ion-initiated oxidation of LDL, thiobarbituric acid reactive substances (TBARS) formation and relative electrophoretic mobility (REM) were significantly inhibited by CBJ at a dilution of 1:10,000. Diene formation during LDL oxidation was evaluated by continuous measurement of absorbance at 234 nm. The time required for cupric ion-initiated LDL oxidations to reach maximum reaction velocity was significantly delayed by 1:10,000 dilutions of CBJ. Non-metal initiated LDL oxidation by 2,2'-azobis-amidinopropane was significantly inhibited by CBJ at dilutions of 1:10,000 and 1:5,000 for REM and TBARS tests, respectively. Protection of LDL from both metal and non-metal based oxidative injury confirms that the effects of CBJ are not due to flavonoid chelation of oxidants but due to a true and potent antioxidant capacity.

Cranberry proanthocyanidins associate with low-density lipoprotein and inhibit Cu2+ -induced oxidation

Posted
Authors
Porter ML, Krueger CG, Wiebe DA, Cunningham DG, Reed JD
Journal
J Sci Food Agr 81(14):1306-1313
Abstract

Abstract: Antioxidant activity of six fractions of cranberry phenolic compounds was determined by
inhibition of Cu2+-induced low-density lipoprotein (LDL) oxidation. The phenolic composition of each fraction was determined by high-performance liquid chromatography. The phenolic fractions were mixed with aliquots of modified human serum prior to LDL isolation. The serum was modified to remove very-low-density lipoprotein and chylomicrons that may bind phenolic compounds. Only fractions 5 and 6 that contained proanthocyanidins (PAs) significantly increased the lag time of LDL oxidation, and the lag time for fraction 6 was significantly higher than for fraction 5. The mass distribution of PAs in these fractions was obtained by matrix-assisted laser desorption/ionisation time- of-flight mass spectrometry, a technique that allows rapid characterisation of the molecular weight distribution in mixtures of oligomeric compounds. Fraction 5 contained trimers through heptamers, whereas fraction 6 contained pentamers through nonamers. In addition, fraction 6 contained PA oligomers with more doubly linked, A-type interflavan bonds. Results indicate that PAs specifically associate with LDL in modified serum and increase the lag time of Cu2+-induced oxidation. Differences between fractions 5 and 6 in PA structure and effects on LDL oxidation suggest that the degree of polymerisation and the nature of the interflavan bond influence antioxidant properties

First-time urinary tract infection and sexual behavior

Posted
Authors
Foxman B, Geiger AM, Palin K, Gillespie B and Koopman JS.
Journal
Epidemiology 6(2):162-8
Abstract

We studied the relation between sexual and health behaviors of women and first-time urinary tract infection (UTI). The study population was women using a university health service who were unmarried, had no UTI history, and who had engaged in sexual activity at least once. We found 86 cases of UTI, defined as one or more urinary symptoms and ^1,000colony-forming units per ml urine of a known pathogen. We randomly sampled 288 controls from the student body. Vaginal intercourse increased the risk of UTI; this risk was further increased with condom use. After adjusting for vaginal intercourse with other birth control methods and recentness of current sexual partnership, a single sex act with a condom in the past 2 weeks increased UTI risk by 43%. Having a sex partner for less than 1 year vs 1 year or more, after adjustment for frequency of vaginal intercourse and birth control method, was associated with about twice the risk of UTI [odds ratio (OR) = 1.97; 95% confidence interval (CI) = 1.04-3.74].After adjusting for frequency of vaginal intercourse, regular drinking of cranberry juice was protective against UTI (OR =
0.48; 95% CI = 0.19-1.02), whereas drinking carbonated soft
drinks appeared to be associated with increased risk (OR =
2.37; 95% CI = 0.75-7.81). Using deodorant sanitary napkins
or tampons was associated with a slight increase in risk of UTI (OR = 1.51; 95% CI = 0.74-3.06). Blacks had five times
greater risk of UTI than whites after adjusting for frequency of vaginal intercourse (OR = 5.2; 95% CI = 1.89-24.63). We
observed only modest differences in health behavior between racial groups.

In vitro activity of cranberry extract against etiological agents of urinary tract infections

Posted
Authors
Rahbar M, Diba K
Journal
Afr J Pharm Pharmacol 4(5):286-288
Abstract

Cranberries have long been the focus of interest for their beneficial effects in preventing urinary tract infections (UTIs). The objective of this study was to determine in vitro activity of cranberry extract on common etiologic agents of urinary tract infections isolated from patients. Filter sterilized methanol extract of cranberry was prepared and used in the present study. The minimum inhibitory concentration (MIC) was evaluated for active crude extract. The MIC value of methanol extract were 0.391 mg/ml for
Enterobacter aerogenes and Staphylococcus aureus whereas the MIC of methanol extract of cranberry were 1.2500 and 0.0195 mg/ml for Escherichia coli and Klebsiella pneumoniae respectively. The lower MIC value of cranberry extract against K. pneumoniae in comparison to other three organisms suggests that K. pneumoniae showed greater sensitivity towards the extracts of the cranberry extract.

MALDI-TOF MS characterization of proanthocyanidins from cranberry fruit (Vaccinium macrocarpon) that inhibit tumor cell growth and matrix metalloproteinase expression in vitro.

Posted
Authors
Neto CC, Krueger CG, Lamoureaux TL, Kondo M, Vaisberg AJ, Hurta RAR, Curtis S, et al
Journal
J Sci Food Agr 86(1):18-25
Abstract

Abstract:Proanthocyanidin-rich extracts were prepared by fractionation of the fruit of theNorthAmerican cranberry (Vaccinium macrocarpon). In vitro growth inhibition assays in eight tumor cell lines showed that selected fractions inhibited the growth of H460 lung tumors, HT-29 colon and K562 leukemia cells at GI50 values ranging from 20 to 80 μgml−1. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of one of these fractions found it to be composed of polyflavan-3-ols, which are primarily tetramers through heptamers of epicatechin containing one or two A-type linkages. Whole cranberry extract and the proanthocyanidin fractions were screened for effect on the expression of matrix metalloproteinases in DU 145 prostate carcinoma cells. The expression of MMP-2 and MMP-9 was inhibited in response to whole cranberry extract and to a lesser degree by the proanthocyanidin fractions

Potential role of dietary flavonoids in reducing microvascular endothelium vulnerability to oxidative and inflammatory insults

Posted
Authors
Youdim KA, McDonald J, Kalt W, Joseph JA
Journal
J Nutr Biochem 13(5):282-288
Abstract

Although antioxidant systems help control the level of reactive oxygen species they may be overwhelmed during periods of oxidative stress. Evidence suggests that oxidative stress components as well as inflammatory mediators may be involved in the pathogenesis of vascular disorders, where localized markers of oxidative damage have been found. In this regard we investigated the putative antioxidant and anti-inflammatory effects of blueberry and cranberry anthocyanins and hydroxycinnamic acids against H2O2 and TNF induced damage to human microvascular endothelial cells. Polyphenols from both berries were able to localize into endothelial cells subsequently reducing
endothelial cells vulnerability to increased oxidative stress at both the membrane and cytosol level. Furthermore, berry polyphenols also reduced TNF induced up-regulation of various inflammatory mediators (IL-8, MCP-1 and ICAM-1) involved in the recruitment of leukocytes to sites of damage or inflammation along the endothelium. In conclusion, polyphenols isolated from both blueberry and cranberry were able to afford protection to endothelial cells against stressor induced up-regulation of oxidative and inflammatory insults. This may have beneficial actions against the initiation and development of vascular diseases and be a contributing factor in the reduction of age-related
deficits in neurological impairments previously reported by us