The influence of cytokinins on proliferation and polyphenol accumulation in shoot cultures of Scutellaria altissima L.

Abstract

S. altissima shoots were cultivated on MS (Murashige and Skoog) solid medium supplemented with IAA (indole-3-acetic acid, 0.57μM) and various concentrations of cytokinin: zeatin, kinetin, BAP (6-benzylaminopurine) (1, 2, 4, 8μM) or TDZ (thidiazuron) (0.2, 0.5, 1μM). The effects on shoot proliferation and their accumulation of pharmacologically valuable phenolic compounds (baicalin, wogonoside, luteolin, luteolin-7-O-glucoside, verbascoside) were evaluated. Ultra-high performance liquid chromatography (UHPLC) was used for quantitative analysis of the compounds accumulated in the plant biomass. The metabolites were identified by comparing their retention time, UV spectra and mass spectra with those of the standard compounds and published data. The highest metabolite contents were recorded in shoots treated with TDZ at a concentration of 1μM; under these conditions, the total level of all evaluated flavones expressed as the sum of baicalin, wogonoside, luteolin and luteolin-7-O-glucoside (17.35mg/g dry wt) was more than twice that of those grown on MS cytokinin-free medium (7.55mg/g dry wt). Verbascoside accumulation was also stimulated by 1μM TDZ; its level was about six times higher than that found on the control medium (6.2mg/g dry wt vs. 1.03mg/g dry wt). The highest number of shoots (5.5–6.4 per explant within five weeks) was achieved with 2–8μM BAP.