Benzophenone synthase from cultured cells of Centaurium erythraea

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

“…7A) in which the labelling patterns of each observed multiply The symmetric labelling pattern of ring A in the experiment with [U- 13 C 6 ]glucose implies that the biosynthetic pathway must involve a c 2 symmetric moiety which is free to rotate before giving rise to ring A. This result is in full accordance with the known polyketide-type pathway of xanthone biosynthesis [7][8][9] via the benzophenone intermediate 12 [8,9] comprising a c 2 symmetric trihydroxyphenyl moiety (Fig. 2).…”

“…Briefly, the cultures were grown in medium containing glucose instead of sucrose as carbon source without significant loss of viability or xanthone productivity. In the first experiment, the cultures were supplemented with a mixture of [1][2][3][4][5][6][7][8][9][10][11][12][13] C]glucose and unlabelled glucose proffered at a ratio of 1 : 2.3 (w/w). Although this experiment could also have been performed with the labelled glucose as the only carbon source, the labelled compound was diluted with unlabelled glucose to reduce the cost.…”

“…An enzyme catalysing the condensation of 3-hydroxybenzoylCoA (11) and malonyl-CoA (10) to a benzophenone intermediate (12, Fig. 2A) has been isolated from Hypericum androsaemum [8,9].…”

“…glucose; reviewed in [1]). Using this approach, we previously showed that the biosynthetic pathways of the tannic acid precursor, gallic acid (8), and the bitter compound, amarogentin (9), produced in Swertia chirata (Gentianaceae) branch off the shikimate pathway at a level before phenylpyruvate (6) (Fig. 1) [2,3].…”

Exploiting the Biosynthetic Potential of Type III Polyketide Synthases

“…Identical replacements (L263M/F265Y/S338G) were also found in the functionally similar Garcinia mangostana L. (mangosteen) BPS [52]. In cell cultures of the medicinal herb Centaurium erythraea, 3-hydroxybenzoyl-CoA (24) is the preferred starter CoA for BPS, giving rise to 2,3 1 ,4,6-tetrahydroxybenzophenone (26, Scheme 7), the precursor of xanthones [53]. More structural studies are needed to provide insights as to why BPS is unable to utilize phenylpropanoid-CoA esters as starters.…”