Back to top

Search

2013

Displaying 21 - 23 of 23

The specific degree-of-polymerization of A-type proanthocyanidin oligomers impacts Streptococcus mutans glucan-mediated adhesion and transcriptome responses within biofilms

Posted: 
September 15, 2013
Authors: 
Feng G, Klein MI, Gregoire S, Singh AP, Vorsa N, Koo H
Journal: 
Biofouling 29(6):629-40
Abstract: 

Cranberry A-type proanthocyanidins (PACs) have been recognized for their inhibitory activity against bacterial adhesion and biofilm-derived infections. However, the precise identification of the specific classes of degree-of-polymerization (DP) conferring PACs bioactivity remains a major challenge owing to the complex chemistry of these flavonoids. In this study, chemically characterized cranberries were used in a multistep separation and structure-determination technique to isolate A-type PAC oligomers of defined DP. The influences of PACs on the 3D architecture of biofilms and Streptococcus mutans-transcriptome responses within biofilms were investigated. Treatment regimens that simulated topical exposures experienced clinically (twice-daily, 60s each) were used over a saliva-coated hydroxyapatite biofilm model. Biofilm accumulation was impaired, while specific genes involved in the adhesion of bacteria, acid stress tolerance, and glycolysis were affected by the topical treatments (vs the vehicle-control). Genes (rmpC, mepA, sdcBB, and gbpC) associated with sucrose-dependent binding of bacteria were repressed by PACs. PACs of DP 4 and particularly DP 8 to 13 were the most effective in disrupting bacterial adhesion to glucan-coated apatitic surface (>85% inhibition vs vehicle control), and gene expression (eg rmpC). This study identified putative molecular targets of A-type cranberry PACs in S. mutans while demonstrating that PAC oligomers with a specific DP may be effective in disrupting the assembly of cariogenic biofilms.

Deconvolution of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry isotope patterns to determine ratios of A-type to B-type interflavan bonds in cranberry proanthocyanidins

Posted: 
February 15, 2013
Authors: 
Feliciano RP, Krueger CG, Shanmuganayagam D, Vestling MM, Reed JD
Journal: 
Food Chem 135(3):1485-93
Abstract: 

A method to deconvolute overlapping isotope patterns in positive mode matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was developed to determine ratios of A- to B-type interflavan bonds in proanthocyanidins that were isolated from cranberry (Vaccinium macrocarpon, Ait.) press cake (c-PAC). Precision and accuracy was validated for binary mixtures of procyanidins A2 and B2. Deconvolution of c-PAC spectra indicated that oligomers with one or more A-type interflavan bonds occur in a higher proportion than oligomers with all B-type interflavan bonds. c-PAC with at least one A-type bond accounted for more than 91% of the oligomers between trimers and undecamers. The c-PAC isotope patterns are highly repeatable, suggesting that the method can be applied to authentication, standardization and efficacy of cranberry products in relationship to urinary tract health. This is the first time MALDI-TOF MS has been used for estimating ratios of A- to B-type bonds in PAC.

Prophylaxis of recurrent urinary tract infection after renal transplantation by cranberry juice and L-methionine

Posted: 
February 15, 2013
Authors: 
Pagonas N, Horstrup J, Schmidt D, Benz P, Schindler R, Reinke P, van der Giet M, Zidek W, Westhoff TH
Journal: 
Transplant Proc 44(10):3017-21
Abstract: 

BACKGROUND: Recurrent urinary tract infections (UTIs) increase mortality and reduce graft survival after renal transplantation. Strategies to prevent recurrent UTIs include L-methionine, cranberry juice, and antibiotics. Data on the efficacy of cranberry and L-methionine, however, are controversial in the general population; there are few data in renal transplant recipients.
METHODS: We performed a retrospective analysis of 82 transplant recipients with recurrent UTIs, who underwent prophylaxis with cranberry juice (2 x 50 mL/d, n = 39, 47.6%), or L-methionine (3 x 500 mg/d, n = 25, 30.5%), or both modalities (n = 18, 21.9%). Thirty patients without prophylaxis served as controls. We analyzed symptoms, pyuria/nitrituria, and incidence of UTI events during 1 year before versus after initiation of prophylaxis.
RESULTS: Prophylaxis highly significantly decreased the annual UTI incidence by 58.3% (P CONCLUSION: Cranberry juice and L-methionine successfully reduced the incidence of UTI after renal transplantation.

Pages