Comparative analysis of phenolic acids and flavonoids in shoot cultures of Eryngium alpinum L. : an endangered and protected species with medicinal value

Phenolic acids and flavonoids, important bioactive compounds of polyphenols, play a significant role in plants; their impact, mainly as antioxidants, on human health have been of great interest in recent years. The genetically uniform shoots of Eryngium alpinum L. cultured in vitro, developed via axillary buds and regenerated from callus tissue, maintained on the media supplemented with various plant growth regulators, were subjected to the phenolic acids and flavonoids quantitative analysis applying HPLC-DAD technique. In vitro cultures give the opportunity to perform the phytochemical studies on the protected species without harvesting the plant material from natural environment. Depending on the hormonal supplementation, the biomass from the shoot cultures accumulated from 11.41 to 25 times more phenolic acids [the total content ranged from 158.66 to 1817.96 mg/100 g of dry weight (DW)] and from 6.8 to 11.8 times more flavonoids (the total content ranged from 29.30 to 51.30 mg/100 g DW) than the shoots from the soil-grown plant. The polyphenols present in the shoot cultures include two phenolic acids: 3,4-dihydroxyphenylacetic and caffeic, four depsides: caftaric, neochlorogenic, chlorogenic, isochlorogenic, and rosmarinic acids, and flavonoids: aglycone-isoquercetin and glucoside-quercitrin. Most of them (apart from chlorogenic and rosmarinic acids) were detected for the first time in this species cultured in vitro. To our best knowledge, the present report is the first one that discusses establishment of Eryngium alpinum L. in vitro cultures and the shoot and callus biomass capacity to produce two subgroups of polyphenols i.e. phenolic acids and flavonoids.