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Miscellaneous: In-Vitro

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Analysis of A-type and B-type highly polymeric proanthocyanidins and their biological activities as nutraceuticals.

Posted: 
July 25, 2014
Authors: 
Yokota K, Kimura H, Ogawa S, Akihiro T
Journal: 
J Chem DOI: 10.1155/2013/352042
Abstract: 

Proanthocyanidins have a series of heteroflavan-3-ols, (+)-catechin/(-)-epicatechin units, which are linked through a single B-type linkage and a doubly linked A-type linkage. Recently, we have performed the structural characterization of seed shells of the Japanese horse chestnut and fruits of blueberry and cranberry. The molecular sizes of them were higher in the order of blueberry > cranberry > seed shells of the Japanese horse chestnut between the respective fractions. For the analysis of terminal and extension units in those proanthocyanidins, the isolated fractions were subjected to the thiolytic cleavage of the B-type linkages using 1-dodecanethiol, and the resulting degradation products were identified by ultraperformance liquid chromatography coupled with electrospray-ionization mass spectrometry. These analyses provided fast and good resolution of the degradation products and revealed higher proportions of A-type linkages compared with B-type linkages in both isolated fractions in the order of the seed shells > cranberry > blueberry. Moreover, the isolated fractions with higher molecular sizes and those more abundant in the proportions of A-type linkages were found to be more effective in the inhibition of pancreatic lipase activity. The results suggest that A-type highly polymeric proanthocyanidins are promising for the attenuation of lipid digestion as dietary supplements.

Development and validation of a sensitive, high-throughput bioassay for the adhesion of radiolabeled E. coli to uroepithelial cells in vitro.

Posted: 
February 15, 2014
Authors: 
Mathison BD, Kimble LL, Kaspar KL, Khoo C, Chew BP
Journal: 
J Nat Prod 76(9):1605-11
Abstract: 

Vaccinium macrocarpon (cranberry) products have been used to prevent uropathogenic Escherichia (E.) coli adherence to uroepithelial cells (UEC) and may help reduce risk of urinary tract infection. Reported herein are the development and validation of an assay to assess antiadhesion activity of V. macrocarpon extracts and human urine. P-fimbriated E. coli (CFT073) was labeled with H-uridine, then co-incubated with HTB-4 UEC at a 400:1 ratio. V. macrocarpon extracts (0-17 mg proanthocyanidins/mL) were added to H-labeled E. coli before co-incubating with UEC. The assay yielded a sensitive inhibition curve: the lower limit of detection and half-maximal inhibitory concentration were 0.43 and 1.59 mg proanthocyanidins/mL for V. macrocarpon extract CEP 55; intra- and interassay coefficients of variance were

Proanthocyanidin A2 purification and quantification of American cranberry (Vaccinium macrocarpon Ait.) products.

Posted: 
February 15, 2014
Authors: 
Lee JM
Journal: 
J Funct Foods 5(1):144-153
Abstract: 

In this study, five common proanthocyanidin purification techniques were evaluated prior to phloroglucinolysis, followed by HPLC analysis. An optimized purification method was then used to identify and quantify the proanthocyanidins (extension and terminal units of epigallocatechin, catechin, epicatechin, A type trimer, and A type dimer) of commercially available cranberry products (juices, concentrates, tablets, and capsules; n=17). Two size exclusion beads (Toyopearl 4 TSK HW-40C and Sephadex LH-20) were found suitable for proanthocyanidin purification, though proanthocyanidin extension and terminal unit composition was contingent upon the cleanup procedure utilized. These data illustrate that purification methods require consideration prior to conducting any cranberry proanthocyanidin analyses, and have to be accounted for when comparing values between studies. Total proanthocyanidin levels ranged from 11.7 (juice) to 436.4 (tablet) mg/100 mL or 100 g values obtained from Sephadex LH-20 purification, while total anthocyanin levels ranged from 0.54 (juice) to 98.00 (tablet) mg/100 mL or 100 g.

Quantification by UHPLC of total individual polyphenols in fruit juices.

Posted: 
February 15, 2014
Authors: 
Diaz-Garcia MC, Obon JM, Castellar MR, Collado J, Alacid M
Journal: 
Food Chem 138(2-3):938-49
Abstract: 

The present work proposes a new UHPLC-PDA-fluorescence method able to identify and quantify the main polyphenols present in commercial fruit juices in a 28-min chromatogram. The proposed method improve the IFU method No. 71 used to evaluate anthocyanins profiles of fruit juices. Fruit juices of strawberry, American cranberry, bilberry, sour cherry, black grape, orange, and apple, were analysed identifying 70 of their main polyphenols (23 anthocyanins, 15 flavonols, 6 hydroxybenzoic acids, 14 hydroxycinnamic acids, 4 flavanones, 2 dihydrochalcones, 4 flavan-3-ols and 2 stilbenes). One standard polyphenol of each group was used to calculate individual polyphenol concentration presents in a juice. Total amount of polyphenols in a fruit juice was estimated as total individual polyphenols (TIP). A good correlation (r(2)=0.966) was observed between calculated TIP, and total polyphenols (TP) determined by the well-known colorimetric Folin-Ciocalteu method. In this work, the higher TIP value corresponded to bilberry juice (607.324 mg/100mL fruit juice) and the lower to orange juice (32.638 mg/100mL fruit juice). This method is useful for authentication analyses and for labelling total polyphenols contents of commercial fruit juices. Copyright 2012 Elsevier Ltd. All rights reserved.

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.

Comparing Procyanidins in Selected Vaccinium Species by UHPLC-MS with Regard to Authenticity and Health Effects

Posted: 
October 30, 2012
Authors: 
Jungfer E, Zimmermann BF, Ruttkat A, Galensa R
Journal: 
J Agric Food Chem 60(38):9688-96
Abstract: 

Cranberry procyanidins have been associated with an effect against urinary tract infections (UTI) for decades, and
European health claims are requested. This study compares the procyanidin profiles and concentrations of American cranberry (Vaccinium macrocarpon Ait.), European cranberry (Vaccinium oxycoccus L.), and lingonberry (Vaccinium vitis-idaea L.) analyzed using ultrahigh-performance liquid chromatoraphy coupled to a triple-quadrupole mass spectrometer with electrospray interface
(UHPLC-MS2). Concentrations of A-type trimers, procyanidin A2, catechin, epicatechin, and B-type dimers and trimers have been evaluated and compared for the first time in the three berries. The data clearly show remarkable differences in the procyanidin profiles and concentrations, especially the lack of A-type trimers in V. oxycoccus; thus, the effectiveness against UTI may vary among the Vaccinium species. These differences can be used to prove authenticity.

Comparison of Health-Relevant Flavanoids in Commonly Consumed Cranberry Products

Posted: 
October 30, 2012
Authors: 
Grace MH, Massey AR, Mbeunkui F, Yousef GG, Lila MA
Journal: 
J Food Sci 77(8):H176-83
Abstract: 

The human health benefits from consumption of cranberry products have been associated with the fruits’ unique flavonoid composition, including a complex profile of anthocyanins and proanthocyanidins. However, when
processed by techniques such as pressing, canning, concentrating, or drying, a number of these natural components may be compromised or inactivated due to physical separation, thermal degradation, or oxidation. Fresh cranberries were compared to freeze-dried berries and individual fruit tissues (skin and peeled fruit). Products examined included cranberry juices (commercial and prepared from concentrate), cranberry sauces (commercial and homemade), and sweetened-dried cranberries (commercial). Freeze-drying resulted in no detectable losses of anthocyanins or proanthocyanidins from cranberry
fruits. Anthocyanins were localized in the skin. Proanthocyanins were higher in the skin than in the flesh, with the exception of procyanidin A-2 dimer which was concentrated in the flesh. Anthocyanins were significantly higher in not-from-concentrate juice than in reconstituted juice from concentrate (8.3 mg and 4.2 mg/100 mL, respectively). Similarly, proanthocyanidins were markedly higher in not-from-concentrate juice compared to juice from concentrate (23.0 mg and 8.9 mg/100 mL, respectively). Homemade sauce contained far higher anthocyanins and proanthocyanidins (15.9 and 87.9 mg/100 g, respectively) than canned sauces processed with whole berries (9.6 and 54.4 mg/100 g, respectively) or jelled-type (1.1 and 16 mg/100 g, respectively). Sweetened-dried cranberries were quite low in anthocyanins
(7.9 mg/100 g), but they still retained considerable proanthocyanidins (64.2 mg/100 g). Commercially processed products contained significantly lower levels of polyphenols as compared to fresh and home-processed preparations. Anthocyanins were more sensitive to degradation than proanthocyanidins.

Transport of Cranberry A-type Procyanidin Dimers, Trimers, and Tetramers across Monolayers of Human Intestinal Epithelial Caco-2 Cells.

Posted: 
April 30, 2012
Authors: 
Ou K, Percival SS, Zou T, Khoo C, Gu L
Journal: 
J Agric Food Chem 15;60(6):1390-6
Abstract: 

A-type procyanidin oligomers in cranberries are known to inhibit the adhesion of uropathogenic bacteria. B-type procyanidins dimers and trimers are absorbed by humans. The absorption of A-type procyanidins from cranberries in humans has not been demonstrated. This study examined the transport of A-type cranberry procyanidin dimers, trimers, and tetramers on differentiated human intestinal
epithelial Caco-2 cell monolayers. Procyanidins were extracted from cranberries and purified using hromatographic methods. Fraction I contained predominantly A-type procyanidin dimer A2 [epicatechin-(2-O-7, 4-8)-epicatechin]. Fraction II contained primarily A-type trimers and tetramers, with B-type trimers, A-type
pentamers, and A-type hexamers being minor components. Fraction I or II in solution were added onto the apical side of the Caco-2 cell membranes. The media at the basolateral side of the membranes were analyzed using HPLC-MSn after 2 h. Data indicated that procyanidin dimer A2 in fraction I and A-type trimers and tetramers in fraction II traversed across Caco-2 cell monolayers with transport ratio of 0.6%, 0.4%, and 0.2%, respectively. This study demonstrated A-type dimers, trimers, and tetramers were transported across Caco-2 cells at low rates, suggesting they could be absorbed by humans after cranberry consumption.

Characterization by high-performance liquid chromatography with diode-array detection coupled to time-of-flight mass spectrometry of the phenolic fraction in a cranberry syrup used to prevent urinary tract diseases, together with a study of its antibacter

Posted: 
January 17, 2012
Authors: 
Iswaldi I, Gomez-Caravaca AM, Arraez-Roman D, Uberos J, Lardon M, Segura-Carretero A, Fernandez-Gutierrez A.
Journal: 
J Pharm Biomed Anal. 58:34-41
Abstract: 

The phenolic fraction of a commercial cranberry syrup, which is purported to have good properties for the prevention of urinary diseases, has been thoroughly characterized using HPLC-DAD-TOF-MS. A study of its antibacterial activity has also been carried out. For this purpose a new HPLC-DAD-TOF-MS method using negative and positive ionization modes was developed and it was thus possible to identify 34 different compounds, nine of which have been tentatively characterized for the first time in cranberry syrup. It is also important to highlight that different coumarins in this matrix were also determined, which, to our knowledge, have not been found previously in the cranberry. The phenolic fraction obtained by HPLC-DAD was found to be 5.47 mg/mL. Catechin and procyanidins belonging to flavanols were the family of compounds found at the highest concentrations (2.37 mg/mL); flavonols were at a concentration of 1.91 mg/mL and phenolic-acid derivatives were found at the lowest concentration (0.15 mg/mL). With regard to antibacterial activity, the incubation of Escherichia coli with cranberry syrup was found to reduce surface hydrophobicity as a function of the concentration of the extract.

GC-MS determination of flavonoids and phenolic and benzoic acids in human plasma after consumption of cranberry juice

Posted: 
November 5, 2010
Authors: 
Zhang K, Zuo Y
Journal: 
J Agric Food Chem 52(2):222-7
Abstract: 

A GC-MS method was developed for the determination of various flavonoids and phenolic and benzoic acids in human plasma. The procedure involved the extraction of flavonoids and phenolic and benzoic acids with ethyl acetate, followed by the derivatization of the phenolic and benzoic compounds with BSTFA (N,O-bis(trimethylsilyl) trifluoroacetamide) + TMCS (trimethylchlorosilane) reagent. The trimethylsilyl derivatives formed were separated and quantitated using GC-MS. Twenty flavonoids and phenolic and benzoic compounds have been well separated in the spiked human plasma without any interference. The average recovery was 79.3%. Several phenolic acids such as o-hydroxybenzoic, p-hydroxyphenylacetic, 2,3-dihydroxybenzoic, 2,4-dihydroxybenzoic, ferulic, sinapic, and benzoic acid were identified and quantified in human plasma after consumption of a cranberry juice. This developed method provides a simple, specific, and sensitive technique for the simultaneous determination of flavonoids and phenolic and benzoic acids in human plasma and is suitable for bioavailability and pharmacokinetic studies.

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