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Cardiovascular Health & Anti-inflammatory Benefits: In-Vitro

Displaying 21 - 30 of 38

Protective effects of the phenolic extracts of fruits against oxidative stress in human lung cells.

Posted: 
July 31, 2012
Authors: 
Boateng J, Verghese M
Journal: 
Int J Pharmacol 8(3):152-60
Abstract: 

Consumption of fruits and the other dietary antioxidants are considered beneficial due to the protection they afford in the pathogenesis associated with oxidative stress. The aim of this study was to evaluate the antioxidative effects of selected fruit extracts (Plums, Apples, Grapes and Cranberries) on human lung fibroblasts (CCD-25LU) exposed to tert-butyl hydroperoxide (tBHP) oxidative stress. Lactate Dehydrogenase (LDH) was used to assess cytotoxicity (cell integrity) and antioxidant enzymes catalase (CAT), glutathione-s-transferase (GST), glutathione peroxidases (GPx) and concentrations of reduced glutathione (GSH) were determined. Results showed that LDH release by cells pretreated with fruits extracts were significantly (p

Free Radical-Scavenging Properties and Antioxidant Activity of Fractions from Cranberry Products

Posted: 
April 30, 2012
Authors: 
Caillet S, Lorenzo G, Côté J, Sylvain JF, Lacroix M
Journal: 
Food Nutr Sci 3;337-347
Abstract: 

Lipid peroxidation inhibition capacity and antiradical activity were evaluated in HPLC fractions of different polarity obtained from two cranberry juices and three extracts isolated from frozen cranberries and pomace containing antho- cyanins, water-soluble and apolar phenolic compounds, respectively. Compounds with close polarities were collected to obtain between three and four fractions from each juice or extract. The cranberry phenols are good free radical-scav- engers, but they were less efficient at inhibiting the lipid peroxidation. Of all the samples tested, the intermediate pola- rity fraction of extract rich in apolar phenolic compounds of fruit presented the highest antiradical activity while the most hydrophobic fractions of the anthocyanin-rich extract from fruit and pomace appeared to be the most efficient at inhibiting the lipid peroxidation. The antioxidant or pro-oxidant activity of fractions increased with the concentration. The phenol polarity and the technological process to manufacture cranberry juice can influence the antioxidant and an- tiradical activities of fractions.

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

Posted: 
January 11, 2011
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: 
January 11, 2011
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 juice inhibits metal and non-metal initiated oxidation of human low density lipoproteins in vitro

Posted: 
January 11, 2011
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: 
January 11, 2011
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

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

Posted: 
January 11, 2011
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: 
January 11, 2011
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

Regulation of vascular endothelial function by procyanidin-rich foods and beverages

Posted: 
January 11, 2011
Authors: 
Caton PW, Pothecary MR, Lees DM, Khan NQ, Wood EG, Shoji T, Kanda T, Rull G and Corder R
Journal: 
J Agric Food Chem 58(7):4008-13
Abstract: 

Flavonoid-rich diets are associated with a lower mortality from cardiovascular disease. This has been linked to improvements in endothelial function. However, the specific flavonoids, or biologically active metabolites, conferring these beneficial effects have yet to be fully defined. In this experimental study of the effect of flavonoids on endothelial function cultured endothelial cells have been used as a bioassay with endothelin-1 (ET-1) synthesis being measured an index of the response.
Evaluation of the relative effects of extracts of cranberry juice compared to apple, cocoa, red wine, and green tea showed inhibition of ET-1 synthesis was dependent primarily on their oligomeric procyanidin content. Procyanidin-rich extracts of cranberry juice triggered morphological changes in endothelial cells with reorganization of the actin cytoskeleton and increased immunostaining for phosphotyrosine residues. These actions were independent of antioxidant activity. Comparison of the effects of apple procyanidin monomers through heptamer showed a clear structure-activity
relationship. Although monomer, dimer, and trimer had little effect on ET-1 synthesis, procyanidin tetramer, pentamer, hexamer, and heptamer produced concentration-dependent decreases with IC50 values of 5.4, 1.6, 0.9, and 0.7 μM, respectively. Levels of ET-1 mRNA showed a similar
pattern of decreases, which were inversely correlated with increased expression of Kruppel-like factor 2 (KLF2), a key endothelial transcription factor with a broad range of antiatherosclerotic actions including suppression of ET-1 synthesis. Future investigations of procyanidin-rich products should assess the role KLF2 induction plays in the beneficial vascular effects of high flavonoid consumption.

Antioxidant levels of common fruits, vegetables, and juices versus protective activity against in vitro ischemia/reperfusion.

Posted: 
November 19, 2010
Authors: 
Bean H, Schuler C, Leggett RE and Levin RM
Journal: 
Int Urol Nephrol 42(2):409-15
Abstract: 

It is well known that antioxidants present in various fruits, vegetables, and juices have the potential to protect the urinary bladder from free radical damage. What is not well understood, however, is how well antioxidant activities detected by chemical methods such as the CUPRAC assay for total antioxidant activity (TAA) predict the level of physiological protection available. It is hypothesized that the level of antioxidant reactivity found by the CUPRAC assay will positively correlate with increased protection in a model of in vitro ischemia/reperfusion. To test this hypothesis, the CUPRAC assay was utilized to determine the antioxidant reactivity of a series of fruits, vegetables, and juices, and the results were compared to the protective ability of selected juices in an established in vitro rabbit bladder model of ischemia/reperfusion. The results of the CUPRAC test showed that cranberry juice had the highest level of antioxidant reactivity, blueberry juice had an intermediate activity, and orange juice had the lowest. It was determined, however, that contrary to the hypothesis, the orange juice was significantly more potent in protecting the bladder against ischemia/reperfusion damage than either blueberry or cranberry juice. Thus, it is concluded that chemical tests for TAA do not necessarily correlate with their physiological activity.

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