Proanthocyanidins (PACs) are naturally occurring flavonoids possessing health beneficial bioactivities. Their quantification often utilizes the 4-dimethylaminocinnamaldehyde (DMAC) spectrophotometric assay with the assumption that molar absorption coefficients (MACs) are similar across the various PAC species. To assess the validity of this assumption, individual PAC monomers and oligomers were examined for their absorbance response with DMAC. Our results have shown that PAC dimers and trimers with interflavan linkage variations exhibited differential absorbance response. Absence of A-type linkage between the terminal and second units in PAC molecule not only impacts absorbance intensity at 640 nm but also elicits a prominent secondary 440 nm absorbance peak. Cranberry (A-type) and cocoa (B-type) oligomeric PACs exhibited differential absorbance (MACs) relationship with degree-of-polymerization. Thus, PAC structural variations have considerable impact on the resulting MAC. The use of DMAC assay in PAC quantification, especially in comparing across specific oligomers and compositions, should not assume MACs are similar.
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http://dx.doi.org/10.1021/acs.jafc.5b05408 | DOI Listing |
Eur J Pharm Sci
December 2023
School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, FI-70210 Kuopio, Finland.
Aldehyde oxidase (AOX) is a cytosolic drug-metabolizing enzyme which has attracted increasing attention in drug development due to its high hepatic expression, broad substrate profile and species differences. In contrast, there is limited information on the presence and activity of AOX in extrahepatic tissues including ocular tissues. Because several ocular drugs are potential substrates for AOX, we performed a comprehensive analysis of the AOX1 expression and activity profile in seven ocular tissues from humans, rabbits, and pigs.
View Article and Find Full Text PDFJ Food Sci
August 2019
Dept. of Food Science and Technology, Virginia Polytechnic Inst. and State Univ., 360 Duck Pond Dr., Blacksburg, VA, 24061, USA.
Multiple analytical methods are used for quantification of total polyphenols and total flavanols in fruit juices and beverages. Four methods were evaluated in this study: Folin-Ciocalteu (F-C), Lowenthal permanganate (L-P), 4-dimethylaminocinnamaldehyde (DMAC), and the bovine serum albumin (BSA) precipitation method. Method validation parameters, including working range, limit of detection, limit of quantitation, precision (repeatability), accuracy, and specificity, were assessed and compared.
View Article and Find Full Text PDFJ Chromatogr A
August 2019
Department of Food Chemistry, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia. Electronic address:
We developed the first four HPTLC methods for the separation of proanthocyanidins according to degree of polymerization on HPTLC diol F plates. Acetonitrile, ethyl acetate, ethyl acetate-formic acid (9:0.1, v/v) and toluene-acetone-formic acid (3:6:1, v/v) were used as developing solvents and 4-dimethylaminocinnamaldehyde (DMACA) as the detection reagent.
View Article and Find Full Text PDFForensic Sci Int Genet
January 2019
Division of Legal Medicine, Graduate School of Medicine, Kobe University, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
We developed an acid-free p-dimethylaminocinnamaldehyde (DMAC) solution containing silicone oil that was suitable for spraying on clothing for analysis of biological samples such as touch DNA. We investigated the effect of this solution and irradiation with blue light emitting diode (LED) light on short tandem repeat (STR) analysis. To examine the effect of adding acid to the DMAC solution on visualizing biological samples, saliva sample was deposited on T-shirt.
View Article and Find Full Text PDFJ Pharm Biomed Anal
January 2018
Natural Products & Food Research and Analysis, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium.
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.
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