Rhodiola rosea is a medicinal plant used by the indigenous Inuit people of Nunavik and Nunatsiavut, Eastern Canada, as a mental and physical rejuvenating agent. This traditional use led to the present investigation of R. rosea in the context of anxiety disorders. An alcohol extract of R. rosea roots was characterized phytochemically and orally administered for three consecutive days to Sprague-Dawley rats at 8 mg/kg, 25 mg/kg, and 75 mg/kg body weight. The rats were subjected to three behavioral paradigms of anxiety, including the elevated plus maze, social interaction, and contextual conditioned emotional response tests. Rhodiola rosea showed dose-dependent anxiolytic activity in the elevated plus maze and conditioned emotional response tests, with moderate effects in the higher-anxiety SI test. The active dose varied according to the anxiety test. In order to elucidate a mechanism, the extract was further tested in an in vitro GABAA-benzodiazepine receptor-binding assay, where it demonstrated low activity. This study provides the first comparative assessment of the anxiolytic activity of Nunavik R. rosea in several behaviour models and suggests that anxiolytic effects may be primarily mediated via pathways other than the GABAA-benzodiazepine site of the GABAA receptor.
This is the first report on the phytochemistry of Nunavik (Québec, Canada) populations of Rhodiola rosea L., a medicinal plant widely used in Eurasia as a tonic and adaptogen. The wild harvested rhizome of the Nunavik populations contained the marker phytochemicals (salidroside, rosarin, rosavin and rosin) reported in authentic Eurasian material, although in lesser amount. Phytochemical profiling by HPLC of the Nunavik populations also showed the presence of new marker compounds not found in the Eurasian material. For quantitative analysis of the phytochemicals, method validation was undertaken, and the marker phytochemicals were measured in the rhizome, leaf, stem, and seeds. The rhizome showed the highest amount of salidroside and rosavins, as well as the highest total phytochemical content. Consequently, the rhizome remains the most medicinally valuable part of R. rosea.
The eriophyid mite Aceria rhodiolae (G. Canestrini) is known to induce galls on the flowers and leaves of roseroot, Rhodiola rosea L., in subarctic and alpine regions of Europe. After discovering galls on the inflorescences of roseroot in Nunavik (Québec), northeastern Canada, we examined the mites extracted from the galls and compared them with specimens of A. rhodiolae from Europe. Through morphological analyses, we demonstrate that the mites from galls in Nunavik are conspecific with A. rhodiolae from Europe. We then provide a detailed redescription of the mite species based on the morphology of adult females and males from Canada and Europe, using a combination of standard light microscopy, confocal microscopy and scanning electron microscopy. Because roseroot is wellknown for its medicinal properties, we tested the hypothesis that roseroot galled by the mite had altered phytochemistry, by using salidroside and rosavins as indicators. Our results show a significant reduction of almost half in salidroside content (45.8%), but not in rosavins. Moreover, because the mite sometimes affects most or all of the inflorescence of R. rosea, it can considerably reduce the production of seeds. We also show that A. rhodiolae is widespread along the Ungava Bay (Nunavik), with 31.5% of 92 sites surveyed having at least a few to numerous plants galled. Given the importance of roseroot as a crop for Inuit communities and as medicinal products used by them and other Canadians, and also in view of the commonness of A. rhodiolae in the Canadian Arctic and its broad distribution in Europe, the impact of the mite and its relationship with roseroot should be examined further in Nunavik and elsewhere.
An HPLC method permitting the simultaneous determination of fourteen analytes (phenylalkanoids and monoterpenoids) from the roots of Rhodiola rosea was developed. A separation was achieved within 35 min using C(18) column material and a water-acetonitrile mobile phase, both containing a 0.05% phosphoric acid gradient system and a temperature of 53 degrees C. The method was validated for linearity, repeatability, limits of detection and limits of quantification. The limits of detection and limits of quantification of 14 phenylalkanoids and monoterpenoids were found to be 0.20-1.0 and 0.5-3.5 microg/mL, respectively. The wavelengths used for quantification of phenylalkanoids and monoterpenoids with a diode array detector were 205, 220 and 251 nm. The method was used to analyze the roots of two species of Rhodiola and commercial extracts of R. rosea and provides preliminary evidence of phytochemical differences between North American and Eurasian populations of R. rosea. LC-mass spectrometry coupled with electrospray ionization (ESI) interface method is described for the identification of phenylalkanoids and monoterpenoids in various Rhodiola samples. This method involved the use of the [M + H](+), [M + NH(4)](+) and [M + Na](+) ions in the positive ion mode with extractive ion monitoring (EIM).
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