Synthesis and Analysis of the Dietary Relevant Isomers of Chlorogenic Acids, Their Derivatives and Hydroxycinnamates

  • Abstract Chlorogenic acids (CGAs) are phenolic natural products, widely present in food materials and plants. Coffee is one of the richest sources of CGAs and one of the most consumed beverages in the world. The LC-MSn methods have been used to detect and characterize CGAs in green Robusta and Arabica coffee beans. During this study, 40 samples of green Robusta and Arabica coffee beans discriminated by their origin and type were investigated for their chlorogenic acid contents. Twenty-one novel CGAs and eight novel classes of CGAs were reported in green coffee beans. An LC-MSn hierarchical scheme was developed for the identification, structure elucidation, and assignment of regiochemistry of triacyl CGAs. The high resolution LC-MS-TOF data of chlorogenic acids was used to discriminate between the Arabica and Robusta coffee beans by the principal component analysis (PCA) approach. In another study on roasted coffee 20 samples of Robusta and Arabica coffee were analyzed by LC-MSn for their content of CGAs, lactones, and shikimates. Fifteen novel CGAs completely absent in green coffee samples were identified in roasted coffee samples. The CGAs of maté were investigated by LC-MSn. Forty-two CGAs were detected and characterized, twenty-four of them for the first time from this source. This was the first time when an LC-MSn method was used for the identification and structure assignment of shikimates. By these LC-MSn methods it became easy to discriminate between the shikimates and CGA lactones. Methyl quinates of CGAs are present in many food materials (including maté) and they are the most common artifacts during the methanolic extraction of chlorogenic acids. In this study an LC-MSn method was developed for their identification and characterization. This is the first time when an LC-MSn method was developed for the identification of hydroxycinnamates. Arnica (Arnica montana) flowers and Burdock (Arctium lappa) roots from the Asteraceae family and Gardeniae Fructus (Gardeniae jasminoids fruit) from the Rubiaceae family were analyzed for their chlorogenic acid contents and chlorogenic acids containing alkoyl residues such as fumaroyl, maloyl, methoxyoxaloyl, hydroxyl-methylglutaroyl, and succinoyl were identified. These chlorogenic acids show different tandem mass spectral behavior compared to previous studies. An LC-MSn method was also developed to discriminate between the feruloylquinic acids and isoferuloylquinic acids. Both classes of polyphenols are possibly present in food materials (nature) and as metabolites. A new protecting group strategy was developed by using allyl ether for the selective synthesis of CGAs and epimers of CGAs. A number of chlorogenic acids and epimers of chlorogenic acids containing muco-quinic acid moiety were synthesized by this approach. This was the first time when caffeoyl- and feruloyl-muco-quinic acids were synthesized efficiently in excellent yield. The epimers of CGAs showed promising enzyme inhibition activity against DnMT3a enzyme.

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Publishing Institution:IRC-Library, Information Resource Center der Jacobs University Bremen
Granting Institution:Jacobs Univ.
Author:Rakesh Jaiswal
Referee:Nikolai Kuhnert, Gerd-Volker Röschenthaler, Michael Clifford
Advisor:Nikolai Kuhnert
Persistent Identifier (URN):urn:nbn:de:101:1-2013052812448
Document Type:PhD Thesis
Date of Successful Oral Defense:2011/03/10
Date of First Publication:2011/05/19
PhD Degree:Chemistry
School:SES School of Engineering and Science
Library of Congress Classification:T Technology / TP Chemical technology / TP500-660 Fermentation industries. Beverages. Alcohol / TP620-660 Nonalcoholic beverages / TP638-650 Chocolate, coffee, tea, etc. / TP645 Coffee
Call No:Thesis 2011/14

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