Abstract
Biosynthetic analysis of diterpene salvinorin A proved its formation via the DOXP pathway.
Salvia divinorum was administered [1-
13C]-
d-glucose in sterile culture of microshoots. Results were analyzed by LCMS and NMR spectroscopic techniques.
Salvinorin A, a neoclerodane diterpenoid, isolated from the Mexican hallucinogenic plant
Salvia divinorum, is a potent kappa-opioid receptor agonist. Its biosynthetic route was studied by NMR and HR-ESI-MS analysis of the products of the incorporation of [1-
13C]-glucose, [Me-
13C]-methionine, and [1-
13C;
3,4-
2H
2]-1-deoxy-
d-xylulose into its structure. While the use of cuttings and direct-stem injection were unsuccessful, incorporation of
13C into salvinorin A was achieved using
in vitro sterile culture of microshoots. NMR spectroscopic analysis of salvinorin A (2.7
mg) isolated from 200 microshoots grown in the presence of [1-
13C]-glucose established that this pharmacologically important diterpene is biosynthesized via the 1-deoxy-
d-xylulose-5-phosphate pathway, instead of the classic mevalonic acid pathway. This was confirmed further in plants grown in the presence of [1-
13C;
3,4-
2H
2]-1-deoxy-
d-xylulose. In addition, analysis of salvinorin A produced by plants grown in the presence of [Me-
13C]-methionine indicates that methylation of the C-4 carboxyl group is catalyzed by a type III
S-adenosyl-
l-methionine-dependent
O-methyltransferase.