Morphogenesis-dependent accumulation of phytoestrogenes in Genista tinctoria in vitro cultures

Abstract

Liquid root, shoot, embryo and suspension cultures of Genista tinctoria were established in SH-modified media to accumulate large amounts of isoflavones of phytoestrogenic activity. In comparison with the herb of G. tinctoria, shoot, embryo and suspension cultures had much higher isoflavone content (six to nine times). The isoflavone group accumulated by the above cultures was composed of 14 compounds with the clear domination of genistin. None of the cultures produced simple flavones; possible causes are discussed. The relations between the compounds, which belong to the metabolic pathway of genistein and daidzein during the growth of all culture types are presented. Root cultures accumulated large amounts of a single metabolite, isoliquiritigenin (978.4 mg/100 g DW), an isoflavone precursor, which is absent in the intact plant. In all culture types, isoflavones were accumulated as intracellular metabolites. The ratio of isoflavone accumulation was influenced greatly by tissue differentiation. Shoot, embryo and suspension cultures showed a negative relation between the process of organogenesis and the accumulation of aglycones and glucosides. The highest isoflavone accumulation was observed in suspension cultures in which HPLC analysis identified 9414.7 mg of genistin per 100 g DW. However, there was a positive relation between the amount of genistin esters produced and the process of morphogenesis. The highest concentration of genistin malonate (1008.2 mg/100 g DW) and genistin acetate (118.95 mg/100 g DW) was observed in shoot cultures.