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Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines
Published on: June 23, 2019
Pyrazines: occurrence, formation and biodegradation
Rudolf Müller1, Sugima Rappert
1Institute of Technical Biocatalysis, Technical University Hamburg-Harburg, 21073 Hamburg, Germany. ru.mueller@tu-harburg.de
Applied Microbiology and Biotechnology
|December 4, 2009
Summary
Pyrazines, ubiquitous natural compounds used as food additives, are poorly understood regarding their degradation. While humans and animals excrete them, specific bacterial degradation pathways and ring cleavage mechanisms remain largely unknown.
Area of Science:
- Biochemistry
- Microbiology
- Food Chemistry
Background:
- Pyrazines are naturally occurring compounds found ubiquitously.
- They are synthesized chemically or biologically and widely used as food flavoring additives.
- Pyrazine formation significantly increases during the heating of food.
Purpose of the Study:
- To review the limited information on pyrazine degradation.
- To highlight the known metabolic pathways in humans and animals.
- To identify knowledge gaps in bacterial degradation mechanisms and ring cleavage.
Main Methods:
- Literature review of existing studies on pyrazine metabolism and degradation.
- Analysis of known excretion pathways in mammals.
- Examination of bacterial degradation capabilities and identified metabolites.
Main Results:
- Pyrazines are primarily excreted in humans and animals as glucuronates or bound to glutathione after hydroxylation.
- The pyrazine ring is not cleaved during mammalian metabolism.
- Certain bacteria can utilize substituted pyrazines as a sole carbon and energy source, with initial metabolites identified in some cases.
Conclusions:
- Mammalian pyrazine metabolism involves excretion but not ring cleavage.
- Bacterial degradation offers a potential route for pyrazine ring cleavage.
- Further research is crucial to elucidate the mechanisms of pyrazine ring cleavage and complete degradation pathways by bacteria.
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