Comparison of Various Techniques for the Extraction, Analysis of Compounds and Determination of Antioxidant Activities of Rhodiola Spp.-A Review

This review presents an overview of the current knowledge regarding the techniques for the extraction of selected Rhodiola species, their bioactive compounds and their underlying mechanisms of action with particular emphasis on free radical scavenging properties. Rhodiola genus (Crassulaceae) is a perennial, which grows naturally in eastern Siberia, Scandinavia, Alaska and northern Europe that has been traditionally used in folk Asian medicine. In this review, we have done a critical evaluation of available literature on Rhodiola species roots and rhizomes, especially R. rosea (L.), R. imbricata (Edgew.), R. crenulata (Hook.f. & Thomson), R. kirilowii (Regel) and R. heterodonta (Hook.f. & Thomson), that have been most thoroughly investigated and described so far. Databases, including Scopus, PubMed and Google Scholar were applied to obtain relevant literature, based on reports mainly in the last 20 years. Here, we improved the list of the most important chemical compounds of Rhodiola spp. - mainly phenolic compounds and essential oils, taking into account their detection methods. In addition, we compared qualitatively and quantitatively different kind of extraction methods and analyzed the results regarding the antioxidant effects of Rhodiola species in vitro and in vivo on mouse and rat.