Anxiolytic‐like effect of Carvacrol (5‐isopropyl‐2‐methylphenol) in mice: involvement with GABAergic transmission

Abstract

Carvacrol (5-isopropyl-2-methylphenol) is a monoterpenic phenol present in the essencial oil of many plants. It is the major component of the essential oil fraction of oregano and thyme. This work presents the behavioral effects of carvacrol in animal models of elevated plus maze (EPM), open field, Rotarod and barbiturate-induced sleeping time tests in mice. Carvacrol (CVC) was administered orally, in male mice, at single doses of 12.5; 25 and 50 mg/kg while diazepam 1 or 2 mg/kg was used as standard drug and flumazenil (2.5 mg/kg) was used to elucidate the possible anxiolytic mechanism of CVC on the plus maze test. The results showed that CVC, at three doses, had no effect on the spontaneous motor activity in the Rotarod test nor in the number of squares crossed in the open-field test. However, CVC decreased the number of groomings in the open-field test. In the plus maze test, CVC, at three doses significantly increased all the observed parameters in the EPM test and flumazenil was able to reverse the effects of diazepam and CVC. Therefore, CVC did not alter the sleep latency and sleeping time in the barbiturate-induced sleeping time test. These results show that CVC presents anxiolytic effects in the plus maze test which are not influenced by the locomotor activity in the open-field test.

Carvacrol attenuates mechanical hypernociception and inflammatory response

“…Although this indicates a central depressant effect of carvacrol, it was observed only the highest dose used and the first time point investigated in spontaneous locomotor test, while the antihypernociceptive effect of this compound was also demonstrated at the lower doses used in this study. Of interest, our previous study demonstrated that carvacrol does not promote alteration of performance in the Rotarod test and neither on open field (Melo et al 2010b). Taken altogether, these observations confirm that the anti-hypernociceptive actions of carvacrol observed in this study are not entirely due to an inhibitory effect on the CNS.…”

“…This monoterpene has also presented an anticonvulsant property , besides anxiolytic (Melo et al 2010b) and antidepressant (Melo et al 2011a) effects with involvement of GABAergic transmission and the dopaminergic system, respectively. Furthermore, local application of carvacrol gel is able to protect against tissue damage in ligature-induced periodontitis in rats, probably by its inhibitory effect on periodontal pathogens (Botelho et al 2009).…”

Chemical composition of hydroethanolic extracts from Siparuna guianensis, medicinal plant used as anxiolytics in Amazon region

“…Type A α-aminobutyric acid (GABAA) receptors are the major inhibitory neurotransmitter receptors in the Central Nervous System, which is involved in epilepsy, sedation and anxiolysis, producing these effects through binding to GABAA receptors (Melo et al, 2010). Anxiolytics facilitate the coupling of GABAergic receptors to GABAA and produce their pharmacological effect by binding to a benzodiazepine recognition site on the GABAA receptor complex (Harris et al, 2008;Ennaceur et al, 2008).…”

Anxiolytic effects of orcinol glucoside and orcinol monohydrate in mice

“…Our interest in the activity of orcinol is not only as an aglycone of OG, but also based on the findings of our review on the bioactivity of some small-molecule natural phenols (constructed only with C, H, and O; M w 5300). These small phenols, including but not limited to sesamol (Kumar et al, 2013), carvacrol (Melo et al, 2010), gallic acid (Dhingra et al, 2012), 4-hydroxybenzaldehyde (Jung et al, 2006), paeonol (Mi et al, 2005), and caffeic acid (Takeda et al, 2003), have been reported to have anxiolytic properties. The conservative hydroxyl group in diverse structures indicates that phenol moiety undertakes a pharmacological role.…”