Trifolium pratense: Friable calli, cell culture protocol and isoflavones content in wild plants, in vitro and cell cultures analyzed by UPLC

ABSTRACT

Abstract Trifolium pratense L., Fabaceae, is a rich source of isoflavones and has become the focus of several studies related to its phytoestrogenic activity. The aim of this study was to establish germination and cell cultures protocol for T. pratense and quantify isoflavones content in cell cultures, in vitro cultured and wild plants harvested in two different seasons. Murashige Skoog medium supplemented with naphthalene acetic acid and kinetin was able to produce the highest formation of friable calli. Calli cultures were analyzed qualitatively after 60 days of culture, and in vitro plants after 30, 45 and 60 days of cultivation. The chemical analysis was performed by ultra performance liquid chromatography, using the linearity curves of daidzein, genistein, formononetin and biochanin A as standards. The concentrations of isoflavones detected in wild plants were different in the two harvest periods and contrasted in content when compared to the in vitro plants. Cell cultures exhibited diverse profiles and concentration of isoflavones, none of which presented the isoflavonoid biochanin A. Pectinase was used to promote reduction of clumps and ended up altering the characteristics of secondary metabolites production in some cultures. Formononetin showed higher concentration in wild red clover samples (15.407 mg g-1), and in the in vitro grown plants the highest concentration was daidzein (17.591 mg g-1) at 60 days. The methods used for this research were effective, and the red clover plants of the analyzed variety can be cultivated in vitro aiming the commercial productivity by having contents greater than or equal to the wild plants in the periods studied, even without the use of elicitors during the cultivation.