Thesis-Final 03 June 2011 pdf - Jacobs University

Background Chapter 2
THE CHLOROGENIC ACIDS
Esters formed between hydroxycinnamates and quinic acid represent a major family
of plant phenolics. Chlorogenic acid (5-CQA) is the most widespread of all
monoesters formed between caffeic and quinic acids (CQA). 57 It is commonly
considered to be a storage form of cinnamic acid derivatives and has been suggested
to be an intermediate in the lignin pathway. 58
Classically, chlorogenic acids (CGA) are a family of esters formed between certain
trans-cinnamic acids and quinic acid (1L-1(OH),3,4/5-tetrahydroxycyclohexane
carboxylic acid) which has axial hydroxyls on carbons 1 and 3, and equatorial
hydroxyls on carbons 4 and 5.
Using the preferred IUPAC numbering, 59 the commonest individual chlorogenic acid
is 5-O-caffeoylquinic acid (5-CQA). It is the only one commercially available and is
still often called chlorogenic acid, although this term should be discouraged.
Figure 8 : (-) Quinic acid
Figure 9: Chlorogenic acid
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