Ein neuer Biosyntheseweg für Anthrachinone: Der Einbau von Shikimisäure in 1.2-Dihydroxy-anthrachinon (Alizarin) und 1.2.4-Trihydroxy-anthrachinon (Purpurin) in Rubia tinctorum L.

Abstract

The biosynthesis of the anthraquinones, alizarin I and purpurin II, in Rubia tinctorum (madder) has been investigated. Acetate- [2-14C] proved to be a precursor only of ring C and in part of the keto groups of the quinone ring. While phenylalanine- [U-14C] was not incorporated into I and II, shikimic acid was found to be a good precursor of these compounds. The radioactivity of shikimic acid-[1,2-14C] could be localized only in ring A; shikimic acid-[U-14C] however was incorporated in toto; the ring being transformed into ring A of the anthraquinone, and the carboxyl group of this acid into one of the keto groups of ring B. These findings demonstrate the existence of a biosynthetic pathway for the formation of anthraquinones in Nature, which is entirely different from the polyacetate route.