Biosynthesis of santiaguine in Adenocarpus foliosus. Part II

Abstract

Lysine is shown, by tracer studies on intact Adenocarpus foliosus plants, to be incorporated unsymmetrically into the αβ′-bipyridyl unit of the cyclobutane-1,3-dicarbonylbis(decahydrobipyridyl) derivative santiaguine (I). The incorporation proceeds via 2,3,4,5-tetrahydropyridine. The acidic portion of santiaguine, α-truxillic acid (trans-2,cis-4-diphenylcycobutane-1,trans-3-dicarboxylic acid), is shown to be present in A. foliosus from feeding experiments with labelled cinnamic acid and is shown to be incorporated into santiaguine. The dimerization of adenocarpine[1-cinnamoyl-1,2,3,4-tetrahydro-5-(2-piperidyl)pyridine] to santiaguine is shown to be enzymically controlled.