Phenylalanine‐independent biosynthesis of 1,3,5,8‐tetrahydroxyxanthone

Abstract

Root cultures of Swertia chirata (Gentianaceae) were grown with supplements of [1‐13C]glucose, [U‐13C6]glucose or [carboxy‐13C]shikimic acid. 1,3,5,8‐Tetrahydroxyxanthone was isolated and analysed by quantitative NMR analysis. The observed isotopomer distribution shows that 1,3,5,8‐tetrahydroxyxanthone is biosynthesized via a polyketide‐type pathway. The starter unit, 3‐hydroxybenzoyl‐CoA, is obtained from an early shikimate pathway intermediate. Phenylalanine, cinnamic acid and benzoic acid were ruled out as intermediates.

Constituintes químicos de Parmotrema lichexanthonicum Eliasaro & Adler: isolamento, modificações estruturais e avaliação das atividades antibiótica e citotóxica

“…No caso de plantas superiores, a rota biossintética para produção de xantonas é mista, sendo uma parte da estrutura produzida a partir da via do chiquimato, e outra a partir da via policetídica. 2 Uma possibilidade interessante é que xantonas sejam precursoras de depsidonas em plantas, através de reações de hidroperoxilação, por rearranjos de Baeyer-Villiger. 3 Em fungos e liquens, substâncias das duas classes são biossintetizadas totalmente pela via policetídica.…”

“…Produtos (10) e (11) produzidos a partir de reações de desmetilação da liquexantona(2), e (11'), não obtido…”

Secondary Metabolite Profile of Transgenic Centaury (Centaurium erythraea Rafn.) Plants, Potential Producers of Anticancer Compounds

“…The initial molecules in the biosynthesis of xanthones are benzoic acid and 3-hydroxybenzoic acid, originated directly from the shikimate pathway [66]. In centaury plants 3-hydroxybenzoic acid is used as the initial compound for tetrahydroxyxanthone biosynthesis [67]. The xanthone biosynthesis is obtained via conversion of 3-hydroxybenzoic acid to 3-hydroxybenzoyl-CoA and tetrahydroxybenzophenone, further converted to trihydroxyxanthone.…”

Biosynthesis of biphenyls and benzophenones – Evolution of benzoic acid-specific type III polyketide synthases in plants

“…Two full-length BPS cDNAs were isolated, however, both heterologously expressed enzymes were inactive, despite the presence of the conserved CysHis-Asn catalytic triad (Liu and Beerhues, unpublished results). 3-Hydroxybenzoic acid is directly derived from the shikimic acid pathway, whereas benzoic acid originates from cinnamic acid by side-chain degradation (Abd El-Mawla et al, 2001;Abd El-Mawla and Beerhues, 2002;Wang et al, 2003).…”