Anxiolytic-like effects of standardized extract of Justicia pectoralis (SEJP) in mice: Involvement of GABA/benzodiazepine in receptor.

Justicia pectoralis (Acanthaceae) is used as an antiinflammatory, antimicrobial and bronchodilator, and its extract exerts an anxiolytic-like effect profile in animal models. This work presents the behavioral effects of an aqueous standardized extract of Justicia pectoralis (SEJP) in animal models, such as the elevated plus maze (EPM), light/dark, open field, rota rod and pentobarbital sleep time. The extract was administered intragastrically to male mice at single doses of 50, 100 and 200 mg/kg, while diazepam 1 or 2 mg/kg was used as a standard drug and flumazenil 2.5 mg/kg was used to evaluate the participation of benzodiazepinic receptors. The results showed that, similar to diazepam (1 mg/kg), SEJP significantly modified all the observed parameters in the EPM test, without altering the general motor activity in the open field, rota rod and pentobarbital sleep time tests. Flumazenil reversed not only the diazepam effect but also the SEJP effect. In the same way, all doses of SEJP increased the time of permanence in the light box in the light/dark test. The results showed that SEJP presented an anxiolytic-like effect, disproving sedative effects.

Antinociceptive effects of (O-methyl)-N-benzoyl tyramine (riparin I) from Aniba riparia (Nees) Mez (Lauraceae) in mice.

The present study examined the antinociceptive effects of (O-methyl) N-benzoyl-tyramine (riparin I, ripI) isolated from the unripe fruit of Aniba riparia in chemical and thermal behavioral models of pain, such as acetic acid-induced abdominal writhing, formalin, and hot-plate tests in mice. Moreover, the involvement of the nitric oxide pathway as well as the opioid system in the antinociceptive action of ripI in the formalin test was investigated. RipI was administered both orally and intraperitoneally to male mice at single doses of 25 and 50 mg/kg. In the acetic acid-induced abdominal writhing, ripI decreased the number of writhings at both doses. In addition, in the formalin test, ripI reduced the paw licking time at both phases of the test. The effect of the highest dose of ripI in mice formalin test on the early phase was not reversed by naloxone (opioid receptor antagonist) but it was reversed by l-arginine (a nitric oxide precursor) in the late phase, suggesting that ripI may not act through opioid system and possibly acts through inhibition of nitric oxide pathway. In the hot-plate test, ripI increased the reaction time in the hot-plate test at the dose of 25 mg/kg, i.p., confirming the result found in the formalin test. Based on the obtained results, it is suggested that ripI presents antinociceptive activity that may be due to peripheral mechanisms (nitric oxide pathway) and central mechanisms, discarding the involvement of opioid system.