Abstract
The bicyclic monoterpene ketone (+)-camphor undergoes lactonization to 1,2-campholide in mature sage (Salvia officinalis L.) leaves followed by conversion to the β-d-glucoside-6-O-glucose ester of the corresponding hydroxy acid (1-carboxymethyl-3-hydroxy-2,2,3-trimethyl cyclopentane). Analysis of the disposition of (+)-[G-3H]camphor applied to midstem leaves of intact flowering plants allowed the kinetics of synthesis of the bis-glucose derivative and its transport from leaf to root to be determined, and gave strong indication that the transport derivative was subsequently metabolized in the root. Root extracts were shown to possess β-glucosidase and acyl glucose esterase activities, and studies with (+)-1,2[U-14C]campholide as substrate, using excised root segments, revealed that the terpenoid was converted to lipid materials. Localization studies confirmed the radiolabeled lipids to reside in the membranous fractions of root extracts, and analysis of this material indicated the presence of labeled phytosterols and labeled fatty acids (C14 to C20) of acyl lipids. Although it was not possible to detail the metabolic steps between 1,2-campholide and the acyl lipids and phytosterols derived therefrom because of the lack of readily detectable intermediates, it seemed likely that the monoterpene lactone was degraded to acetyl CoA which was reincorporated into root membrane components via standard acyl lipid and isoprenoid biosynthetic pathways. Monoterpene catabolism thus appears to represent a salvage mechanism for recycling mobile carbon from senescing oil glands on the leaves to the roots.
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Selected References
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- Burbott A. J., Loomis W. D. Evidence for metabolic turnover of monoterpenes in peppermint. Plant Physiol. 1969 Feb;44(2):173–179. doi: 10.1104/pp.44.2.173. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Croteau R., El-Bialy H., El-Hindawi S. Metabolism of monoterpenes: lactonization of (+)-camphor and conversion of the corresponding hydroxy acid to the glucoside-glucose ester in sage (Salvia officinalis). Arch Biochem Biophys. 1984 Feb 1;228(2):667–680. doi: 10.1016/0003-9861(84)90037-7. [DOI] [PubMed] [Google Scholar]
- Croteau R., El-Hindawi S., El-Bialy H. Purification of monoterpenyl glycosides by gel-permeation and hydrophobic-interaction chromatography on polyacrylamide (Bio-Gel P-2). Anal Biochem. 1984 Mar;137(2):389–393. doi: 10.1016/0003-2697(84)90102-7. [DOI] [PubMed] [Google Scholar]
- Croteau R., Felton M., Karp F., Kjonaas R. Relationship of Camphor Biosynthesis to Leaf Development in Sage (Salvia officinalis). Plant Physiol. 1981 Apr;67(4):820–824. doi: 10.1104/pp.67.4.820. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Croteau R., Karp F. Biosynthesis of monoterpenes: enzymatic concersion of neryl pyrophosphate to 1,8-cineole, alpha-terpineol, and cyclic monoterpene hydrocarbons by a cell-free preparation from sage (Salvia officinalis). Arch Biochem Biophys. 1976 Oct;176(2):734–746. doi: 10.1016/0003-9861(76)90217-4. [DOI] [PubMed] [Google Scholar]
- Croteau R., Karp F. Demonstration of a cyclic pyrophosphate intermediate in the enzymatic conversion of neryl pyrophosphate to borneol. Arch Biochem Biophys. 1977 Nov;184(1):77–86. doi: 10.1016/0003-9861(77)90328-9. [DOI] [PubMed] [Google Scholar]
- Croteau R., Martinkus C. Metabolism of Monoterpenes: Demonstration of (+)-Neomenthyl-beta-d-Glucoside as a Major Metabolite of (-)-Menthone in Peppermint (Mentha Piperita). Plant Physiol. 1979 Aug;64(2):169–175. doi: 10.1104/pp.64.2.169. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Croteau R., Sood V. K. Metabolism of Monoterpenes : Evidence for the Function of Monoterpene Catabolism in Peppermint (Mentha piperita) Rhizomes. Plant Physiol. 1985 Apr;77(4):801–806. doi: 10.1104/pp.77.4.801. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Croteau R., Sood V. K., Renstrøm B., Bhushan R. Metabolism of Monoterpenes : Early Steps in the Metabolism of d-Neomenthyl-beta-d-Glucoside in Peppermint (Mentha piperita) Rhizomes. Plant Physiol. 1984 Nov;76(3):647–653. doi: 10.1104/pp.76.3.647. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Loomis W. D. Overcoming problems of phenolics and quinones in the isolation of plant enzymes and organelles. Methods Enzymol. 1974;31:528–544. doi: 10.1016/0076-6879(74)31057-9. [DOI] [PubMed] [Google Scholar]
- Ougham H. J., Taylor D. G., Trudgill P. W. Camphor revisited: involvement of a unique monooxygenase in metabolism of 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid by Pseudomonas putida. J Bacteriol. 1983 Jan;153(1):140–152. doi: 10.1128/jb.153.1.140-152.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tang C. S., Young C. C. Collection and Identification of Allelopathic Compounds from the Undisturbed Root System of Bigalta Limpograss (Hemarthria altissima). Plant Physiol. 1982 Jan;69(1):155–160. doi: 10.1104/pp.69.1.155. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yu C. A., Gunsalus I. C. Monoxygenases. VII. Camphor ketolactonase I and the role of three protein components. J Biol Chem. 1969 Nov 25;244(22):6149–6152. [PubMed] [Google Scholar]
