Cayer C.,University of Ottawa |
Ahmed F.,University of Ottawa |
Filion V.,University of Ottawa |
Saleem A.,University of Ottawa |
And 5 more authors.
Planta Medica | Year: 2013
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. © Georg Thieme Verlag KG Stuttgart.
Amiguet V.T.,University of Ottawa |
Jewell L.E.,University of Ottawa |
Jewell L.E.,University of Guelph |
Mao H.,University of Ottawa |
And 6 more authors.
Canadian Journal of Microbiology | Year: 2011
This study investigated the antibacterial activity of glycolipid-rich extracts of the brown macroalga Fucus evanescens in cell culture. Accessions were collected on the Arctic coast of Ungava Bay, Nunavik, Quebec. The crude ethyl acetate extract of these accessions showed strong antibacterial activity (≥4 log10 cfu) against Hemophilus influenzae, Legionella pneumophila, Propionibacterium acnes (ATCC and clinical isolate), and Streptococcus pyogenes at 100 μg/mL. This algal extract inhibited by 3 log10 Clostridium difficile and methicillin-resistant Staphylococcus aureus, whereas Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa were not significantly affected. Further investigations of the activity of a glycolipid-rich fraction, extracted with dichloromethane, against Propionibacterium acnes showed an MIC100 of 50 μg/mL, with an inhibition of more than 99% at only 7.8 μg/mL. The main active compound, a b-D-galactosyl O-linked glycolipid, was synthesized for the bioassay and showed an MIC 100 of 50 μg/mL but lost its activity more quickly with only 50% of inhibition at 12.5 μg/mL. Therefore, the semipurified F. evanescens extract could be a good choice for future research into the development of alternative treatments for acne therapy.