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Odor Qualities and Thresholds of Physiological Metabolites of 1,8‐Cineole as an Example for StructureActivity Relationships Considering Chirality Aspects
Author(s) -
Kirsch Frauke,
Buettner Andrea
Publication year - 2013
Publication title -
chemistry and biodiversity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 70
eISSN - 1612-1880
pISSN - 1612-1872
DOI - 10.1002/cbdv.201300097
Subject(s) - odor , chemistry , enantiomer , chirality (physics) , ionone , gas chromatography , stereochemistry , chromatography , organic chemistry , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
The present study aimed at analyzing the odor properties of a group of physiological human metabolites of the odorant 1,8‐cineole: 2,3‐dehydro‐, α 2,3‐epoxy‐, α / β 2‐hydroxy‐, α 3‐hydroxy‐, 4‐hydroxy‐, 7‐hydroxy‐, 9‐hydroxy‐, 2‐oxo‐, and 3‐oxo‐1,8‐cineole. These metabolites constitute a group of structurally closely related molecules, which differ mainly in nature and position of O‐containing functional groups. They thus offer the possibility to correlate odor properties with molecular structure, i.e. , to establish structureodor relationships of compounds that are biologically generated from a potent odorant as parent substance. Generally, the metabolites preserved the eucalyptus‐like odor quality of 1,8‐cineole but showed additional odor notes such as sweet, citrus‐like, plastic‐like, earthy, musty , and faecal , which made them distinguishable. The individual enantiomers of chiral molecules also exhibited different odors. With the exception of 2,3‐dehydro‐1,8‐cineole, all metabolites showed a highly decreased odor threshold in comparison to 1,8‐cineole. The determination of odor qualities and odor thresholds was accomplished by gas chromatography/olfactometry (GC/O) on achiral and chiral GC capillaries. The results were correlated with common theories on structureodor relationships.