Qualitative and quantitative LC-MS analysis of different Rhodiola rosea rhizome extracts

Rhodiola rosea L. (Sedum roseum (L.) Scop.) is an herbaceous plant in the family Crassulaceae, forming thick rhizomes. Ethanolic macerates of its underground parts have been used in folk medicine for a long time [ 1 ]. Adaptogenic properties were confirmed in rats and rabbits in vivo [ 2 ]-[ 4 ]. Main compounds thought to be responsible for its activities are phenylethanoid glycoside salidroside and a group of cinnamyl alcohol glycosides, rosarin, rosavin and rosin [ 5 ]. Rhodiola rosea rhizome batches collected at two mountainous habitats in Carinthia (Austria) on three time points over the vegetation period of 2015 were prepared as ethanolic macerates (38, 70, 96% V/V) and 85% methanolic ASE extracts. They were qualitatively and quantitatively analyzed by UHPLC-PDA-ESI-MS, using a C-18 column (Agilent ZORBAX SB-C18, 2.1x100mm, 1.8µm) and gradient elution with acetonitrile/water + 0.1% formic acid. It was aimed to compare characteristics and effectivity of different extraction methods. 18 compounds were identified in methanolic ASE extracts of Rhodiola rosea. Methanolic ASE of freeze-dried plant material produced highest yield in salidroside, cinnamyl alcohol glycosides and flavonols. Among macerates of fresh plant material, 96% ethanol was the preferable solvent. Macerates of higher ethanol content showed increased yield and lowered hydrolysis of glycosides during extraction. Rhodiola rosea is a great source for different substances of potential pharmacological relevance. Rhizomes of wild origins seemed to underly great variability in chemical composition dependent on growth site.