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Theophylline metabolism in higher plants
1Department of Biology, Ochanomizu University, Faculty of Science, Tokyo, Japan.
Biochimica Et Biophysica Acta
|August 29, 1997
Summary
Plants metabolize theophylline differently than mammals, with tea and maté converting it into various compounds including caffeine. Other plants show limited theophylline breakdown, highlighting diverse plant metabolic pathways.
Area of Science:
- Plant biochemistry
- Metabolomics
- Pharmacognosy
Background:
- Theophylline, a purine alkaloid, is found in several plant species.
- Understanding its metabolism in plants is crucial for comparative biochemistry and potential applications.
Purpose of the Study:
- To investigate the metabolic fate of [8-(14)C]theophylline in various plant systems.
- To compare theophylline metabolism across different plant species and with mammalian pathways.
Main Methods:
- Incubation of plant tissues (leaf, root) and cell cultures with radiolabeled theophylline ([8-(14)C]theophylline).
- Analysis of metabolic products using techniques to identify and quantify theophylline derivatives and breakdown products.
- Comparative analysis of metabolic pathways in purine alkaloid-producing and non-producing plants.
Main Results:
- Extensive uptake and metabolism of theophylline observed in tea, Camellia irrawadiensis, and maté leaves.
- Conversion of theophylline to 3-methylxanthine, xanthine, allantoin, allantoic acid, and CO2 in purine alkaloid-containing species.
- Limited theophylline uptake and metabolism in non-purine alkaloid-producing plants (Avena sativa, Vigna mungo, Catharanthus roseus).
- No conversion of theophylline to mammalian catabolites (1-methyluric acid, 1,3-dimethyluric acid) in any tested higher plants.
- Identification of a theophylline degradation pathway: theophylline → 3-methylxanthine → xanthine → uric acid → allantoin → allantoic acid → CO2 + NH3.
- Evidence for a salvage pathway in tea and maté: theophylline → 3-methylxanthine → theobromine → caffeine.
Conclusions:
- Higher plants exhibit diverse theophylline metabolism, differing significantly from mammals.
- A common degradation pathway involving ureides exists in higher plants.
- Salvage pathways leading to caffeine synthesis are active in certain purine alkaloid-rich plants.
- Plant theophylline metabolism provides insights into secondary metabolite biosynthesis and interspecies biochemical variations.
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