Differential accumulation of xanthones in methyl-jasmonate- and yeast-extract-treated cell cultures of Centaurium erythraea and Centaurium littorale

Abstract

Cell-suspension cultures of Centaurium erythraea and Centaurium littorale (Gentianaceae) respond to methyl jasmonate and yeast extract with a differential accumulation of xanthones. Methyl jasmonate induced the formation of 1-hydroxy-3,5,6,7-tetramethoxyxanthone, the amount of which increased in both cell cultures around 10 h after addition. A substantial increase in the activity of phenylalanine ammonia-lyase (PAL) was not observed. When challenged with yeast extract the cell cultures accumulated 1,5-dihydroxy-3-methoxyxanthone. This appeared rapidly after addition of yeast extract in C. erythraea but its amount in C. littorale increased only after a lag phase of 25 h. While PAL activity in C. erythraea was strongly suppressed a fourfold increase in its activity was found in C. littorale. Both elicited xanthones accumulated intracellularly. A scheme for xanthone biosynthesis in the two cell cultures is proposed.

Benzophenone synthase from cultured cells of Centaurium erythraea

“…Similarly, benzophenone synthase activity is also not stimulated by addition of methyl jasmohate, indicating that this potential signal molecule in the elicitation process [19] affects only peripheral reactions of the constitutive xanthone biosynthetic pathway in C. erythraea, as discussed earlier [6].…”

“…When cultured C. erythraea cells were treated with methyl jasmonate 1-hydroxy-3,5,6,7-tetramethoxyxanthone accumulated but the activity of phenylalanine ammonia lyase did not appreciably increase [6]. Similarly, benzophenone synthase activity is also not stimulated by addition of methyl jasmohate, indicating that this potential signal molecule in the elicitation process [19] affects only peripheral reactions of the constitutive xanthone biosynthetic pathway in C. erythraea, as discussed earlier [6].…”

“…A central step in the proposed biosynthetic pathway of this constituent is the formation of the Cla skeleton, i.e. an intermediate benzophenone [6].…”

Indução de metabólitos secundários em plântulas de Hypericum brasiliense Choisy crescendo in vitro

“…Xantonas, tal como 1,5-diihidroxixantona, são formadas no metabolismo do ácido chiquímico, assim como rutina e quercetina (Beerhues & Berger, 1995;Vermerris & Nicholson, 2006). No entanto, aqui não se observou variação no sentido de que o aumento de uma substância deve ser acompanhado do Indução de metabólitos secundários em plântulas de Hypericum brasiliense Choisy crescendo in vitro aumento de outras substâncias da mesma rota, mostrando que o controle do nível dessas substâncias são independentes.…”

“…Porém, o estresse causado pelo tratamento com ácido metiljasmônico não levou a aumentos relevantes nos níveis dos compostos fenólicos aqui estudados, mesmo para a xantona 1,5-diihidroxixantona, como já havia sido observado em Hypericum androsaemum (Beerhues & Berger, 1995). Resultados com ácido metiljasmônico também já foram obtidos com suspensões celulares e calos de H. perforatum cultivados no escuro, induzindo a produção de hipericina (Walker et al, 2002).…”