Accumulation of valuable secondary metabolites: phenolic acids and flavonoids in different in vitro systems of shoot cultures of the endangered plant species—Eryngium alpinum L.

In vitro cultures give the opportunity to perform the phytochemical studies on the protected species without harvesting the plant material from the natural environment. Shoots of Eryngium alpinum L. were multiplied on Murashige and Skoog (MS) medium in various systems, namely on the solid media and in two liquid cultures—stationary and agitated, as well as via regeneration from callus. The biomass increments were closely correlated with the number of shoots arising from one explant, which was connected with the supplementation of the culture media with the studied plant growth regulators. The methanolic extracts from shoots grown in the tested systems were subjected to phenolic acids and flavonoids qualitative and quantitative analysis. Biomass from in vitro shoot cultures accumulated from 19.59 to 32.95 times more phenolic acids [the total content ranged from 272.52 to 458.38 mg/100 g dry weight (DW)] and from 3.02 to 4.43 times more flavonoids (the total content ranged from 100.03 to 146.98 mg/100 g DW), depending on the culture system, than the extracts from basal leaves from the intact plant (13.91 and 33.16 mg/100 g DW, respectively). The phenolics present in shoot cultures include seven phenolic acids—3,4-dihydroxyphenylacetic, caftaric, caffeic, neochlorogenic, chlorogenic, isochlorogenic, and rosmarinic acids, and three flavonoids—isoquercetin, quercitrin and robinin. The best system for shoot proliferation resulting in the highest biomass growth and phenolic acids and flavonoids accumulation was solid culture on MS medium with BAP, IAA, and GA3 (each 1.0 mg/l). The aim of this work was to check the effect of various culture systems (stationary and agitated, on solidified and in liquid media) on the production of phenolic compounds in E. alpinum shoots cultured in vitro.