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Miscellaneous: In-Vitro

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Some New Findings Regarding the Antiadhesive Activity of Cranberry Phenolic Compounds and Their Microbial-Derived Metabolites against Uropathogenic Bacteria.

Posted: 
February 19, 2019
Authors: 
González de Llano D, Liu H, Khoo C, Moreno-Arribas MV, Bartolomé B.
Journal: 
J Agric Food Chem. 2019 Feb 12. doi: 10.1021/acs.jafc.8b05625
Abstract: 

Findings concerning the antiadhesive activity of cranberry phenolic compounds and their microbial-derived metabolites against Gram-negative ( Escherichia coli ATCC 53503 and DSM 10791) and Gram-positive ( Enterococcus faecalis 04-1) bacteria in T24 cells are reported. A-Type procyanidins (A2 and cinnamtannin B-1) exhibited antiadhesive activity (at concentrations ≥250 μM), a feature that was not observed for B-type procyanidins (B2). The metabolites hippuric acid and α-hydroxyhippuric acid also showed effective results at concentrations ≥250 μM. With regard to conjugated metabolites, sulfation seemed to increase the antiadhesive activity of cranberry-derived metabolites as 3-(3,4-dihydroxyphenyl)propionic acid 3- O-sulfate presented active results, unlike its corresponding nonsulfated form. In contrast, methylation decreased antiadhesive activity as 3,4-dihydroxyphenylacetic acid was found to be active but not its corresponding methylated form (4-hydroxy-3-methoxyphenylacetic acid). As a whole, this work sustains the antiadhesive activity of cranberry-derived metabolites as one of the mechanisms involved in the beneficial effects of cranberries against urinary tract infections.

Advantages of a Validated UPLC-MS/MS Standard Addition Method for the Quantification of A-Type Dimeric and Trimeric Proanthocyanidins in Cranberry Extracts in Comparison with Well-Known Quantification Methods.

Posted: 
September 4, 2018
Authors: 
Dooren, I. van Foubert, K. Theunis, M. Naessens, T. Pieters, L. Apers, S.
Journal: 
Journal of Pharmaceutical and Biomedical Analysis;148:32-41.
Abstract: 

The berries of Vaccinium macrocarpon, cranberry, are widely used for the prevention of urinary tract infections. This species contains A-type proanthocyanidins (PACs), which intervene in the initial phase of the development of urinary tract infections by preventing the adherence of Escherichia coli by their P-type fimbriae to uroepithelial cells. Unfortunately, the existing clinical studies used different cranberry preparations, which were poorly standardized. Because of this, the results were hard to compare, which led sometimes to conflicting results. Currently, PACs are quantified using the rather non-specific spectrophotometric 4-dimethylaminocinnamaldehyde (DMAC) method. In addition, a normal phase HPTLC-densitometric method, a HPLC-UV method and three LC-MS/MS methods for quantification of procyanidin A2 were recently published. All these methods contain some shortcomings and errors. Hence, the development and validation of a fast and sensitive standard addition LC-MS/MS method for the simultaneous quantification of A-type dimers and trimers in a cranberry dry extract was carried out. A linear calibration model could be adopted for dimers and, after logarithmic transformation, for trimers. The maximal interday and interconcentration precision was found to be 4.86% and 4.28% for procyanidin A2, and 5.61% and 7.65% for trimeric PACs, which are all acceptable values for an analytical method using LC-MS/MS. In addition, twelve different cranberry extracts were analyzed by means of the newly validated method and other widely used methods. There appeared to be an enormous variation in dimeric and trimeric PAC content. Comparison of these results with LC-MS/MS analysis without standard addition showed the presence of matrix effects for some of the extracts and proved the necessity of standard addition. A comparison of the well-known and widely used DMAC method, the butanol-HCl assay and this newly developed LC-MS/MS method clearly indicated the need for a reliable method able to quantify A-type PACs, which are considered to be the pharmacologically active constituents of cranberry, since neither the DMAC or butanol-HCl assays are capable of distinguishing between A and B-type PACs and therefore cannot detect adulterations with, for example, extracts with a high B-type PAC content. Hence, the combination of the DMAC method or butanol-HCl assay with this more specific LC-MS/MS assay could overcome these shortcomings.

Determination of Flavanols by Liquid Chromatography with Fluorescence Detection. Application to the Characterization of Cranberry-Based Pharmaceuticals Through Profiling and Fingerprinting Approaches.

Posted: 
September 4, 2018
Authors: 
Bakhytkyzy, I. Nunez, O. Saurina, J.
Journal: 
Journal of Pharmaceutical and Biomedical Analysis; 2018. 156:206-213.
Abstract: 

In this work, a new method based on reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection (FLD) was established for the determination of catechins and related oligomeric proanthocyanidins (PACs) in cranberry-based pharmaceuticals. Compounds were recovered by liquid extraction using methanol/water/hydrochloric acid (60:39:1, v:v:v) as the extraction solvent. The chromatographic separation was carried out using a core-shell C18 column under an elution program based on 0.1% formic acid in water and methanol as the components of the mobile phase. The flow rate was 0.4 mL min-1 and the injection volume was 5 micro L. Chromatograms were acquired at 280 nm by UV-vis absorption and at lambda ex 280 nm and lambda em 347 nm by fluorescence spectroscopy. Compared to UV detection, FLD demonstrated both increased sensitivity and selectivity to avoid interfering signals from other phenolic compounds present in the samples. Data resulting from the analysis of cranberry-based products was exploited to tackle an exploratory characterization and classification using principal component analysis. Samples were clustered according to their compositions and those enriched with PACs with antibacterial activity were clearly distinguished from the others.

Development of a Thiolysis HPLC Method for the Analysis of Procyanidins in Cranberry Products.

Posted: 
September 4, 2018
Authors: 
Gao C; Cunningham DG; Liu H; Khoo C; Gu L.
Journal: 
Journal of Agricultural & Food Chemistry. 66(9):2159-2167
Abstract: 

The objective of this study was to develop a thiolysis HPLC method to quantify total procyanidins, the ratio of A-type linkages, and A-type procyanidin equivalents in cranberry products. Cysteamine was utilized as a low-odor substitute of toluene-alpha-thiol for thiolysis depolymerization. A reaction temperature of 70 degreeC and reaction time of 20 min, in 0.3 M of HCl, were determined to be optimum depolymerization conditions. Thiolytic products of cranberry procyanidins were separated by RP-HPLC and identified using high-resolution mass spectrometry. Standards curves of good linearity were obtained on thiolyzed procyanidin dimer A2 and B2 external standards. The detection and quantification limits, recovery, and precision of this method were validated. The new method was applied to quantitate total procyanidins, average degree of polymerization, ratio of A-type linkages, and A-type procyanidin equivalents in cranberry products. Results showed that the method was suitable for quantitative and qualitative analysis of procyanidins in cranberry products.

Evaluation of Polyphenol Anthocyanin-Enriched Extracts of Blackberry, Black Raspberry, Blueberry, Cranberry, Red Raspberry, and Strawberry for Free Radical Scavenging, Reactive Carbonyl Species Trapping, Anti-Glycation, Anti- Beta -Amyloid Aggregation.

Posted: 
September 4, 2018
Authors: 
Ma H, Johnson SL, Liu W, DaSilva NA, Meschwitz S, Dain JA, Seeram NP
Journal: 
International Journal of Molecular Sciences;19(2):461.
Abstract: 

Glycation is associated with several neurodegenerative disorders, including Alzheimer's disease (AD), where it potentiates the aggregation and toxicity of proteins such as beta -amyloid (A beta ). Published studies support the anti-glycation and neuroprotective effects of several polyphenol-rich fruits, including berries, which are rich in anthocyanins. Herein, blackberry, black raspberry, blueberry, cranberry, red raspberry, and strawberry extracts were evaluated for: (1) total phenolic and anthocyanins contents, (2) free radical (DPPH) scavenging and reactive carbonyl species (methylglyoxal; MGO) trapping, (3) anti-glycation (using BSA-fructose and BSA-MGO models), (4) anti-A beta aggregation (using thermal- and MGO-induced fibrillation models), and, (5) murine microglia (BV-2) neuroprotective properties. Berry crude extracts (CE) were fractionated to yield anthocyanins-free (ACF) and anthocyanins-enriched (ACE) extracts. The berry ACEs (at 100 micro g/mL) showed superior free radical scavenging, reactive carbonyl species trapping, and anti-glycation effects compared to their respective ACFs. The berry ACEs (at 100 micro g/mL) inhibited both thermal- and MGO-induced A beta fibrillation. In addition, the berry ACEs (at 20 micro g/mL) reduced H2O2-induced reactive oxygen species production, and lipopolysaccharide-induced nitric oxide species in BV-2 microglia as well as decreased H2O2-induced cytotoxicity and caspase-3/7 activity in BV-2 microglia. The free radical scavenging, reactive carbonyl trapping, anti-glycation, anti-A beta fibrillation, and microglial neuroprotective effects of these berry extracts warrant further in vivo studies to evaluate their potential neuroprotective effects against AD.

Regulation of Redox Status in Neuronal SH-SY5Y Cells by Blueberry (Vaccinium myrtillus L.) Juice, Cranberry (Vaccinium macrocarpon A.) Juice and Cyanidin.

Posted: 
September 4, 2018
Authors: 
Casedas G; Gonzalez-Burgos E; Smith C; Lopez V; Gomez-Serranillos MP.
Journal: 
Food & Chemical Toxicology. 118:572-580.
Abstract: 

Blueberry and cranberry are fruits with high polyphenol content, particularly anthocyanins. As cyanidin derivatives have been identified as one of the most representative polyphenols in berry juices, cyanidin has been designated for a better comparison and understanding of the potential neuroprotection of juices obtained from two Vaccinium species. Neuroblastoma SH-SY5Y cells were previously treated with different concentrations of lyophilized blueberry juice, cranberry juice or cyanidin for 24h and oxidative stress was then generated with hydrogen peroxide (100muM) for 30min. Cytoprotective properties of cranberry juice, blueberry juice or cyanidin were evaluated using different methodologies such as mitochondrial activity (MTT), TBARS and ROS production, antioxidant enzymes (CAT, SOD) and antioxidant properties (ORAC, FRAP). Results indicated that blueberry and cranberry juices as well as cyanidin increased mitochondrial activity and reduced intracellular ROS production and lipid peroxidation induced by hydrogen peroxide. Furthermore, these berry juices and cyanidin upregulated the activity of the antioxidant enzymes catalase and superoxide dismutase. Finally, in vitro antioxidant capacities were confirmed by ORAC and FRAP assays demonstrating the potential of cyanidin and cyanidin-containing products for pharmaceutical or nutritional applications to prevent oxidative stress in neuronal cells.

Single-Laboratory Validation for Determination of Total soluble Proanthocyanidins in Cranberry Using 4-Dimethylaminocinnamaldehyde.

Posted: 
September 4, 2018
Authors: 
Sintara, M. Li Lin Cunningham, D. G. Prior, R. L. Wu XianLi Chang, T.
Journal: 
Journal of AOAC International; 101(3):805-809
Abstract: 

American cranberry (Vaccinium macrocarpon) is native to Eastern North America. Recent studies have suggested that the A-type proanthocyanidins (PACs) in cranberries are effective in preventing urinary tract infection. To meet the growing interest in the cranberry market, an accurate, reliable, and simple method to determine PAC concentration is needed. In this study, a modified method using 4-dimethylaminocinnamaldehyde to quantify total PACs in cranberry products was validated. Cranberry juice extract powder, cranberry capsules containing juice extract, and cranberry juice concentrate were used as the samples in this study. With the modified method, the calibration curves for proanthocyanidin A2 had correlation coefficients (r2) of >0.99. The recoveries of two different concentrations after spiking were 97.1 and 99.1%, and the RSDs for repeatability and reproducibility were <2.7 and <1.6%, respectively.

Effect of Proanthocyanidin-Enriched Extracts on the inhibition of Wear and Degradation of Dentin Demineralized Organic Matrix.

Posted: 
April 4, 2018
Authors: 
Boteon AP; Kato MT; Buzalaf MAR; Prakki A; Wang L; Rios D; Honorio HM.
Journal: 
Archives of Oral Biology. 84:118-124
Abstract: 

OBJECTIVES: The aim of this study was to evaluate the effect of Cranberry and Grape seed-enriched extract gels in inhibiting wear and degradation of demineralized organic matrix (DOM). DESIGN: 225 dentin specimens obtained from bovine incisors were randomly allocated into 5 groups (n=45): 10% Grape seed extract gel (GSE), 10% Cranberry extract gel (CE), 0.012% Chlorhexidine gel (CX), 1.23% NaF gel (F), and no active compound gel (P, placebo). Before the treatments, samples were demineralized by immersion in 0.87M citric acid, pH 2.3 (36h). Then, the studied gels were applied once over dentin for 1min. Next, the samples were immersed in artificial saliva containing collagenase obtained from Clostridium histolyticum for 5days. The response variable for dentin wear was depth of dentin loss measured by profilometry and for collagen degradation was hydroxyproline determination. Data were analyzed by ANOVA followed by Tukey's test and Pearson Correlation Test (p<0.05). RESULTS: Grape seed extract significantly reduced dentin wear compared to the other groups (p<0.05). Cranberry extract and Chlorhexidine did not differ statistically and were able to reduce wear when compared to NaF and placebo treatments. The hydroxyproline analysis showed that there was no significant difference among groups for all treatments (p<0.05). Correlation analysis showed a significant correlation between the amount of degraded DOM evaluated by profilometry and the determination of hydroxyproline. CONCLUSION: Cranberry extract was able to reduce the dentin wear and collagen degradation, likely due to the proanthocyanidin content and its action. Therefore, Cranberry could be suggested as an interesting natural-based agent to prevent dentin erosion.

Inhibitory Activity of Chokeberry, Bilberry, Raspberry and Cranberry Polyphenol-Rich Extract Towards Adipogenesis and Oxidative Stress in Differentiated 3T3-L1 Adipose Cells.

Posted: 
April 4, 2018
Authors: 
Kowalska K, Olejnik A, Szwajgier D, Olkowicz M.
Journal: 
PLoS ONE 12(11):e0188583
Abstract: 

Berries are a rich source of antioxidants and phytochemicals that have received considerable interest for their possible relations to human health. In this study, the anti-adipogenic effect of polyphenol-rich extract obtained from chokeberry Aronia melanocarpa (Michx.) Elliot, raspberry Rubus idaeus L., bilberry Vaccinium myrtillus L. and cranberry Vaccinium macrocarpon Aiton fruits and its underlying molecular mechanisms were investigated in differentiated 3T3-L1 adipose cells. Treatment with the extract (25-100 mug/mL) significantly decreased lipid accumulation and reactive oxygen species generation in adipocytes without showing cytotoxicity. Real-time PCR analysis revealed that the extract at a concentration of 100 mug/mL suppressed adipogenesis and lipogenesis via the down-regulation of PPARgamma (67%), C/EBPalpha (72%), SREBP1 (62%), aP2 (24%), FAS (32%), LPL (40%), HSL (39%), and PLIN1 (32%) gene expression. Moreover, the extract significantly increased the expression of adiponectin (4.4-fold) and decreased leptin expression (90%) and respectively regulated the production of these adipokines in 3T3-L1 adipocytes. The obtained results suggest that the analyzed extract may be a promising source of bioactive compounds that support long-term weight maintenance and promote the effective management of obesity.

5-(3',4'-dihydroxyphenyl)- Gamma -Valerolactone and its Sulphate Conjugates, Representative Circulating Metabolites of Flavan-3-ols, Exhibit Anti-Adhesive Activity Against Uropathogenic Escherichia Coli in Bladder Epithelial Cells.

Posted: 
August 15, 2017
Authors: 
Mena, P. Llano, D. G. de Brindani, N. Esteban-Fernandez, A. Curti, C. Moreno-Arribas, M. V. Rio, D. del Bartolome, B.
Journal: 
Journal of Functional Foods 29:275-280
Abstract: 

Urinary tract infections (UTI) are mostly caused by uropathogenic Escherichia coli (UPEC). Cranberry-based products have shown preventive effects against UTI, and this has been partially attributed to their A-type proanthocyanidin content. However, recent evidence reports phenyl- gamma -valerolactones as the most relevant urinary metabolites of cranberry procyanidins, and candidates these compounds as plausible responsible for the protective effects of cranberries against UTI. This paper studied the inhibition of the adherence of UPEC ATCCReg. 53503TM to T24 bladder epithelial cells by physiological concentrations of differently sulphated dihydroxyphenyl- gamma -valerolactones. Moreover, the transformations of these molecules in the cell media were evaluated by UHPLC-MSn. All dihydroxyphenyl- gamma -valerolactone derivatives showed anti-adhesive activity at 100 micro M, while 5-(3'-hydroxyphenyl)- gamma -valerolactone-4-O-sulphate also showed neuro-protective effects at 50 micro M. Some compounds underwent extensive metabolism during cell incubation, mainly deconjugation of sulphate moieties and opening of the lactone ring. These results shed light on the flavan-3-ol metabolites behind the prophylactic effect of cranberries against UTI.

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