NEPETALACTOL OXIDOREDUCTASE IN TRICHOMES OF THE CATMINT NEPETA-RACEMOSA

Isomers of (7S)-nepetalactone are the principal constituents of the es sential oil accumulated by plants of the genus Nepeta (catmints), with the cis,cis-isomer predominating in the catmint N. racemosa. An enzym e which catalyses the NAD(+)-dependent oxidation of cis,cis-nepetalact ol to cis,cis-nepetalactone has been identified in cell-free extracts of N. racemosa leaves. This enzyme has been partially purified and has been shown to be located within trichomes present on the surface of l eaves of this species. Because glandular trichomes have been shown to be the site of accumulation of nepetalactones in N. racemosa and N. ca taria, the presence of such activity within the trichomes suggests tha t nepetalactol may be an intermediate in the biosynthesis of nepetalac tone. (C) 1998 Elsevier Science Ltd. All rights reserved.