Characterization of the anxiolytic activity of Nunavik Rhodiola rosea

Targets and underlying mechanisms related to the sedative and hypnotic activities of saponins from Rhodiola rosea L. (crassulaceae)

Rhodiola rosea L. (Crassulaceae) are popularly used as a natural supplement for the treatment of insomnia and anxiety. Here, saponin extracts from R. rosea were investigated for their roles on relieving sleeplessness. The levels of neurotransmitters, hormones, and inflammation cytokines in plasma, and the expression of 5-hydroxytryptamine (5-HT), γ-aminobutyric acid (GABA), prostaglandin D2 (PGD2), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in the hypothalamus and hippocampus were detected using ELISA, RT-PCR, and western blotting. First, the butanol fraction extracted from R. rosea was collected as the total saponins (HJT-I), then a saponin-rich fraction (HJT-II) was obtained after the further purification of HJT-I. The saponin contents of HJT-I and HJT-II were 28.92% and 65.69%, respectively. Second, behavioral tests were performed and showed that both HJT-I and HJT-II could effectively reduce the duration of immobility in the tail suspension test, and shorten sleep latency and prolong the sleep duration time in the sodium barbital-induced sleeping test, with HJT-II better than HJT-I. Third, ELLISA results showed that the concentrations of GABA, 5-HT, norepinephrine (NA), PGD2, and IL-1β in plasma were significantly increased after HJT-I and HJT-II administration, while IL-6 was decreased. HJT-I and HJT-II also exhibited differential modulation of the receptors of 5-HT, GABA, PGD2, and IL-1β expression. In hypothalamus, HJT-II was more powerful than HJT-I in regulation of the GABA_ARα2, GABA_ARα3, and glutamic acid decarboxylase (GAD) 65/67 expression, as well as 5-HT_2A and IL-1β. As for DPR and PGD2, HJT-II was more effective in the hippocampus. The efficacy of HJT-I was better than HJT-II at stimulating GABA_ARα2, GAD 65/67, 5-HT_1A, and IL-1β expression in the hippocampus. In conclusion, the potential sedative and hypnotic effects of HJT-I and HJT-II may possibly be related to the serotonergic, GABA_Aergic, and immune systems, while the underlying mechanism of HJT-I and HJT-II differed from each other.

Running out of time to smell the roseroots: Reviewing threats and trade in wild Rhodiola rosea L

ETHNOPHARMACOLOGICAL RELEVANCE

Rhodiola rosea L. has a circumpolar distribution and is used in ethnomedicines of Arctic peoples, as well as in national systems of traditional medicine. Since the late 20th century, global demand for R. rosea has increased steadily, in part due to clinical research supporting new uses in modern phytotherapy. Global supply has been largely obtained from wild populations, which face threats from poorly regulated and destructive exploitation of the rootstocks on an industrial scale.

AIM OF THE STUDY

To evaluate (i) the conservation status, harvesting and trade levels of R. rosea, in order to determine whether international trade should be monitored, (ii) the current state of experimental and commercial farming and whether cultivation may play a role to take pressure off wild stocks, and (iii) evidence of substitution of other Rhodiola species for R. rosea as an indicator of overexploitation and rarity.

MATERIALS AND METHODS

We reviewed published studies on R. rosea biology and ecology, as well as information on impacts of wild harvest, on management measures at the national and regional levels, and on the current level of cultivation from across the geographic range of this species. Production and trade data were assessed and analysed from published reports and trade databases, consultations with R. rosea farmers, processors of extracts, and trade experts, but also from government and news reports of illegal harvesting and smuggling.

RESULTS AND CONCLUSIONS

Our assessment of historical and current data from multiple disciplines shows that future monitoring and protection of R. rosea populations is of time-sensitive importance to the fields of ethnobotany, ethnopharmacology, phytochemistry and phytomedicine. We found that the global demand for R. rosea ingredients and products has been increasing in the 21st century, while wild populations in the main commercial harvesting areas continue to decrease, with conservation issues and reduced supply in some cases. The level of illegal harvesting in protected areas and cross border smuggling is increasing annually coupled with increasing incidences of adulteration and substitution of R. rosea with other wild Rhodiola species, potentially negatively impacting the conservation status of their wild populations, but also an indicator of scarcity of the genuine article. The current data suggests that the historical primary reliance on sourcing from wild populations of R. rosea should transition towards increased sourcing of R. rosea from farms that are implementing conservation oriented sustainable agricultural methods, and that sustainable wild collection standards must be implemented for sourcing from wild populations.

Twenty "must-read" research articles for primary care providers in Nunavik: scoping study and development of an information tool

While health needs in Nunavik are distinct, there is a scarcity of knowledge transfer intended for local primary care providers. We aimed to build an information tool in the form of a newsletter and a website to share with them a selection of relevant research articles. To identify such articles, a scoping study of Inuit health research published between 2012 and 2017 was conducted. Selection criteria were adapted from the framework of information mastery. After a database search yielding 2896 results, publications were screened for eligibility. Next, the 226 eligible articles were evaluated and scored for their relevance, their methods (including community participation), their local applicability and their clinical utility. The 20 highest-scored articles were selected for dissemination in a newsletter. They were summarised and presented in 6 thematic emails: Child Development, Infectious Diseases, Traditional and Modern Medicine, Metabolism, Nutrition and Contaminants, and Inuit Perspectives. The newsletter was sent to over 190 health workers and regional stakeholders in Nunavik and was also published online. We hope that this project will foster knowledge sharing and inter-sectorial collaboration between research, public health and clinical care. Trends in Inuit health research are discussed.

Extract and Active Principal of the Neotropical Vine Souroubea sympetala Gilg. Block Fear Memory Reconsolidation

Background:Souroubea sympetala Gilg. is a neotropical vine native to Central America, investigated as part of a targeted study of the plant family Marcgraviaceae. Our previous research showed that extract of S. sympetala leaf and small branch extract had anxiolytic effects in animals and acts as an agonist for the GABA_A receptor at the benzodiazepine binding site. To date, the potential effects of S. sympetala and its constituents on reconsolidation have not been assessed. Reconsolidation, the process by which formed memories are rendered labile and susceptible to change, may offer a window of opportunity for pharmacological manipulation of learned fear. Here, we assessed the effects of S. sympetala crude extract and isolated phytochemicals (orally administered) on the reconsolidation of conditioned fear. In addition, we explored whether betulin (BE), a closely related molecule to betulinic acid (BA, an active principal component of S. sympetala), has effects on reconsolidation of learned fear and whether BE may synergize with BA to enhance attenuation of learned fear.

Method: Male Sprague–Dawley rats received six 1.0-mA continuous foot shocks (contextual training). Twenty-four hours later, rats were re-exposed to the context (but in the absence of foot shocks). Immediately following memory retrieval (recall), rats received oral administration of S. sympetala extract at various doses (8–75 mg/kg) or diazepam (1 mg/kg). In separate experiments, we compared the effects of BA (2 mg/kg), BE (2 mg/kg), and BA + BE (2 mg/kg BA + 2 mg/kg BE). The freezing response was assessed either 24 h later (day 3) or 5 days later (day 7). Effects of phytochemicals on fear expression were also explored using the elevated plus maze paradigm.

Results:S. sympetala leaf extract significantly attenuated the reconsolidation of contextual fear at the 25- and 75-mg/kg doses, but not at the 8-mg/kg dose. Furthermore, BA + BE, but not BA or BE alone, attenuated the reconsolidation of learned fear and exerted an anxiolytic-like effect on fear expression.

Sacred Maya incense, copal (Protium copal - Burseraceae), has antianxiety effects in animal models

ETHNOPHARMACOLOGICAL RELEVANCE

The Maya have traditionally used copal, Protium copal, as incense during ceremonies since pre-Columbian times. Anecdotally, copal (when burned as incense), is thought to elicit mentally uplifting and calming effects. The main objective of this study was to determine whether the incense elicits anxiolytic-like behavior in animal models using rats. A second objective was to characterize active constituents and discern potential mechanism(s) of action, specifically the involvement of the GABAergic and endocannabinoid (eCB) systems. Despite the extensive Central American use of this resin, there are currently no known scientific behavioral or pharmacological studies done with the incense.

MATERIALS AND METHODS

Quantification of the triterpenes in the copal resin and cold trapped incense was achieved by HPLC MS. Behavioral effects in rats were assessed using the elevated plus maze (EPM), social interaction (SI) test, conditioned emotion response (CER) and Novel object recognition (NOR) paradigms. Rats were exposed to burning copal (200 mg) over 5 min in a smoking chamber apparatus and then immediately tested in each behavioral paradigm. Follow-up SI tests were done using two antagonists flumazenil (1 mg/kg) and AM251 (1 mg/kg) administered systemically. Inhibition of MAGL (monoacylglycerol lipase) was measured by microplate assay with recombinant human enzyme and probe substrate.

RESULTS

Phytochemical analysis revealed that copal resin and incense had high α- and β-amyrins and low lupeol triterpene content. Exposure to Protium copal incense significantly reduced anxiety-like behavior in the SI and CER tests. In contrast, no anxiolytic effects were observed in the EPM. The CER effect was time dependent. Both flumazenil and AM251 blocked the anxiolytic activity of copal revealing the involvement of GABAergic and endocannabinoid systems. Copal, as well as the identified triterpenes, potently inhibited monoacylglycerol lipase (MAGL) activity in vitro (IC₅₀ ≤ 811 ng/mL).

CONCLUSIONS

This is the first study to show that copal incense from Protium copal elicits anxiolytic-like effects in fear and social interaction models as evidenced by a reduced learned fear behavior and an increase in active social interaction. It's high α and β-amyrin content suggests behavioral effects may be mediated, in part, by the known action of these terpenes at the benzodiazepine receptor. Furthermore, P. copal's observed activity through the eCB system via MAGL offers a new potential mechanism underlying the anxiolytic activity.

Salidroside, a Bioactive Compound of Rhodiola Rosea, Ameliorates Memory and Emotional Behavior in Adult Mice

Rhodiola Rosea (R. Rosea) is a plant used in traditional popular medicine to enhance cognition and physical performance. R. Rosea medicinal properties have been related to its capability to act as an adaptogen, i.e., a substance able to increase the organism's resistance to a variety of chemical, biological, and physical stressors in a non-specific way. These adaptogen properties have been mainly attributed to the glycoside salidroside, one of the bioactive compounds present in the standardized extracts of R. Rosea. Here, we aimed to investigate whether a single dose of salidroside is able to affect memory and emotional behavior in wild type adult mice. We performed fear conditioning to assess cued and contextual memory, elevated plus maze and open field to evaluate anxiety, and tail suspension test to evaluate depression. Our results showed that a single i.p. administration of salidroside was able to enhance fear memory and exerted an anxiolytic and antidepressant effect. These data confirmed the adaptogenic effect of R. Rosea bioactive compounds in animal models and suggest that salidroside might represent an interesting pharmacological tool to ameliorate cognition and counteract mood disorders.

Anxiolytic activity and active principles of Piper amalago (Piperaceae), a medicinal plant used by the Q'eqchi' Maya to treat susto, a culture-bound illness

ETHNOPHARMACOLOGICAL RELEVANCE

The medicinal plant, Piper amalago L. (Piperaceae), is used traditionally by Q'eqchi' Maya healers for the treatment of "susto" a culture-bound syndrome. Previous research suggests that susto symptoms may be a manifestation of anxiety. The objectives were to characterize the effect of ethanolic extract of P. amalago in behavioral assays of anxiety at doses representative of traditional use and to isolate active principles.

MATERIALS AND METHODS

Rats treated orally with low dose ethanolic extracts of P. amalago leaves (8-75mg/kg) were tested in several behavioral paradigms including the elevated plus maze (EPM), social interaction (SI), and conditioned emotional response (CER) tests, and compared to diazepam, a positive control. The active anxiolytic principle was isolated by bioassay guided isolation using an in vitro GABAA competitive binding assay.

RESULTS

Extracts had significant anxiolytic activity in all behavioral tests, with the strongest activity in the SI and the CER paradigms. In an in vitro GABAA competitive binding assay, a 66.5µg/mL concentration of P. amalago ethanol extract displaced 50% of the GABAA-BZD receptor ligand [(3)H]-Flunitrazepam. Bioassay-guided fractionation identified a furofuran lignan, a molecule with structural similarity to yangambin, with high affinity for the GABAA-BZD receptor as the principle bioactive.

CONCLUSION

The results suggest that the ethnobotanical use of this plant may have a pharmacological basis in its anxiolytic activity, as demonstrated in animal behaviour tests.