Purification of Phenylalkanoids and Monoterpene Glycosides from Rhodiola rosea L. Roots by High‐speed Counter‐current Chromatography

Abstract

Rhodiola rosea L. is a medicinal herb used for its adaptogenic properties. The main active components are the phenylpropanoids collectively referred to as rosavins. To develop an isolation method for phytochemicals present in Rhodiola rosea roots using high-speed counter-current chromatography (HSCCC). The roots of Rhodiola rosea were extracted with methanol and fractionated using liquid-liquid partition and polyamide column clean-up. The purified fraction (100 mg) was subjected to semi-preparative HSCCC using the two-phase solvent system ethyl acetate:butanol:water (3:2:5). The head-to-tail elution mode was employed with a flow rate of 1.5 mL/min and a rotary speed of 1000 rpm. The separation yielded six main fractions with four components more than 90% pure. The sixth fraction was further purified using semi-preparative HPLC with a Synergi-hydro RP C₁₈ -column to obtain rosin and geranyl 1-O-α-l-arabinopyranosyl(1 → 6)-β-d-glucopyranoside. The main components isolated were rosavin (3.4 mg, 97% purity), salidroside (0.5 mg, 90% purity), benzyl-O-β-d-glucopyranoside (1.2 mg, 85% purity), rosarin (1.3 mg, 99% purity), rosiridin (1.8 mg, 92% purity), rosin (1.2 mg, 95% purity) and geranyl 1-O-α-l-arabinopyranosyl(1 → 6)-β-d-glucopyranoside (6.5 mg, 97% purity). The identity and purity of these components were confirmed using ultrafast liquid chromatography-diode-array detector-MS/MS analysis, ¹H- and ¹³C-NMR spectroscopy. High-speed counter-current chromatography was successful in the isolation of several phytochemicals present in Rhodiola rosea roots, including two components that are not commercially available.