Solid phase concentration of phenolic compounds from the aqueous medicinal raw plant material extracts on the example of St. John’s wort (Hypericum perforatum L.)

The investigation of the phenolic compounds solid-phase extraction from the medicinal raw plant material extracts using several concentrating materials of various compositions was carried out. The sorbents based on the octadecylsilane (Strata C18-E), styrene-divinylbenzene copolymer (Strata X) and graphitized carbon (Supelclean ENVI-Carb) were studied. The comparative evaluation of their sorption parameters under the competitive dynamic sorption conditions of various phenolic compounds from their extracts was performed. On the basis of the sorption parameters ("breakthrough volumes" and dynamic sorbent capacities), the desorption conditions of 9 phenolic substances were optimized; recoveries and concentration factors for each compound were established. It was shown that the flavonoids and their glycosides can be selectively extracted by C18 sorbents, and it was expedient to use a polymeric type of sorbent for the simultaneous extraction of both flavonoids and phenolic acids. In that case the high recoveries of phenolic components were observed, despite the different plant matrix of the following objects: St. John's Wort ( Hypericum perforatum L.), thyme ( Thumus serpullum L.), nettle ( Urtica dioica L.), linden ( Tilia cordata Mill.). The recoveries for the phenolcarboxylic and cinnamic acid derivatives ranged from 92 to 107%, and for flavonoids – 87 to 122% respectively. The perspective of using graphitized carbon sorbent for the various phenolic compounds' extracting and concentrating were discussed. Key words : solid phase extraction (SPE), flavonoids, phenolic acids, medicinal raw material, HPLC DOI: http://dx.doi.org/10.15826/analitika.2018.22.3.013 (Russian) Е . А . Shil'ko, V.V. Milevskaya, Z.A. Temerdashev, N V. Kiseleva, Kuban State University» (KubSU), ul. Stavropolskaia, 149, Krasnodar, 350040, Russian Federation