title: Influence of Degree-of-Polymerization and Linkage on the Quantification of Proanthocyanidins using 4-Dimethylaminocinnamaldehyde (DMAC) Assay.
abstract: 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.
authors.affiliation: Department of Plant Biology and Pathology, Rutgers University , New Brunswick, New Jersey 08901, United States.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Plant Biology and Pathology, Rutgers University , New Brunswick, New Jersey 08901, United States.
authors.forename: Ajay P
authors.initials: AP
authors.lastname: Singh
authors.affiliation: Hershey Center of Health and Nutrition, The Hershey Company , Hershey, Pennsylvania United States.
authors.forename: William J
authors.initials: WJ
authors.lastname: Hurst
authors.affiliation: Planta Analytica, LLC. , Danbury, Connecticut 17033, United States.
authors.forename: Jan A
authors.initials: JA
authors.lastname: Glinski
authors.affiliation: Department of Orthodontics and Divisions of Pediatric Dentistry & Community Oral Health, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Hyun
authors.initials: H
authors.lastname: Koo
authors.affiliation: Department of Plant Biology and Pathology, Rutgers University , New Brunswick, New Jersey 08901, United States.|Philip E. Marucci Center for Blueberry and Cranberry Research and Extension, Rutgers University , Chatsworth, New Jersey 08019, United States.
authors.forename: Nicholi
authors.initials: N
authors.lastname: Vorsa
mesh_terms: D002099:Cacao; D002934:Cinnamates; D019281:Dimerization; D005638:Fruit / Q000737:chemistry; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry; D058105:Polymerization; D044945:Proanthocyanidins / Q000032:analysis* / Q000737:chemistry*; D012997:Solvents; D013053:Spectrophotometry / Q000379:methods*; D029799:Vaccinium macrocarpon
chemical_list: D002934:Cinnamates; D010936:Plant Extracts; D044945:Proanthocyanidins; D012997:Solvents; C018523:4-dimethylaminocinnamaldehyde
keywords: 4-dimethylaminocinnamaldehyde; DMAC; proanthocyanidin; procyanidin; spectrophotometry