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Biosynthesis of flavonoids—XXXIV. Occurrence of the “NIH-shift” in flavonoid biosynthesis

1969; Elsevier BV; Volume: 8; Issue: 1 Linguagem: Inglês

10.1016/s0031-9422(00)85801-x

1873-3700

Arne Sutter, Hans Grisebach,

Seed and Plant Biochemistry

Abstract The incorporation of p -tritio-cinnamic acid [3- 14 C] into the flavonols kaempferol and quercetin in pea seedlings ( Pisum sativum ) and into the isoflavones formononetin and biochanin A in chana seedlings ( Cicer arietinum ) was investigated. The retention of tritium found was: kaempferol, 85 per cent; quercetin, 49 per cent; formononetin, 80 per cent; and biochanin A, 81 per cent. Degradation of the labelled formononetin to 3-nitro-5-tritio-4-methoxybenzoic acid proved that the tritium had migrated to a position ortho to the 4′-hydroxyl group. The results are discussed in terms of the chronological sequence of steps during flavonoid biosynthesis, in particular when hydroxylation in ring B occurs.