BIOSYNTHESIS OF THE COUMARINS. VI. FURTHER STUDIES ON HERNIARIN FORMATION IN LAVENDER,
Abstract
Analyses of lavender plants, with careful precautions to avoid enzymic hydrolysis, have shown that herniarin exists in the plant at least 99% in a bound form, presumably cis-2-glucosyloxy-4-methoxycinnamic acid (cis-GMC). Traces of a glycoside of 2-hydroxy-4methoxycinnamic acid (HMC), which appears identical with trans-GMC, have also been identified. Several pieces of evidence, principally the failure to demonstrate conversion of p-coumaric acid to p-methoxycinnamic acid by a trapping technique, now indicate that the latter compound, although an efficient precursor of herniarin when administered, may not be a natural intermediate in herniarin formation. O-Methylation, therefore, may occur at a later stage. Feedings of C(14)-labelled HMC have shown that it is converted to herniarin about onefifth as efficiently as trans-GMC, the best herniarin precursor yet found. Trapping experiments with C(14)labelled p-coumaric or p-methoxycinnamic acid and nonradioactive HMC demonstrated conversion of both labelled compounds to free HMC and to a bound form hydrolyzable with emulsin, presumably trans-GMC. The consistently higher specific activity of the bound HMC in these experiments suggests that free HMC, contrary to earlier assumptions, may not be an intermediate in the formation of bound HMC. Syntheses of herniarin-1C(14) and HMC-carboxy-C(14) are described. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 03, 1964
- Accession Number
- AD0614511
Entities
People
- Stewart A. Brown
Organizations
- National Research Council Canada