Evaluation of Effects of N-(2-Hydroxybenzoyl) Tyramine (Riparin II) from Aniba riparia (NEES) MEZ (Lauracea) in Anxiety Models in Mice

Abstract

Aniba riparia (NEES) MEZ, from the Lauraceae family, is popularly named "louro" in Brazil. It belongs to a genus mainly found in Central Amazonia and Guiana comprising approximately 40 species of lowland shrubs and trees. 1,2) From the green fruit of Aniba riparia, collected from the Amazonas state of Brazil, were isolated three substances with broad spectrum antimicrobial activity: methyl ethers of N-benzoyl tyramine (riparin I), N-(2-hydroxybenzoyl) tyramine (riparin II) and N-(2,6-dihydroxybenzoyl) tyramine (riparin III) 1) which were later synthesized.3)It was previously reported that (O-methyl)-N-(2,6-dihydroxybenzoyl) tyramine (riparin III) has potent smooth muscle relaxant activity 4,5) and this spasmolytic effect was possibly related to a reduction of intracellular Ca 2ϩ concentration. 6)Recently, it was reported by us that riparin I 7) and III 8,9) presented antianxiety effects in mice treated with the doses of 25 and 50 mg/kg. As far as we know, there are no studies in the literature on the central actions of riparin II. However, this substance is an N-(2-hydroxybenzoyl) tyramine, and previous data showed that the spectrum of tyramine actions are similar to those of norepinephrine. In fact, some reports related that tyramine-rich foods when ingested by individuals taking antidepressant drugs, such as monoamino oxidase inhibitors, might result in a prolonged increase in blood pressure. 10)Hereby, these findings led us to investigate the behavioral effects of riparin II on animals models of locomotion, anxiolytic and myorelaxant activities. MATERIALS AND METHODS AnimalsMale Swiss mice weighing 25-30 g were used in these experiments. The animals were housed in plastic cages, 30 to cage, under a 12 h light/dark cycle (light on at 7:00 a.m.) at constant temperature of 23Ϯ1°C with free access to food and water, except during the experiments. Animals were treated in accordance to the current law and the NIH Guide for Care and Use of Laboratory Animals.Drugs Riparin II was emulsified with 3% Tween 80 (Sigma-U.S.A.) and dissolved in distilled water. Animals were treated with the compound in doses of 25, 50 and 75 mg/kg, once, 30 or 60 min before the experiments when administered by intraperitoneal or oral routes, respectively. Controls received vehicle at the same volume (10 ml/kg) and the same route as the treated groups. Diazepam (DZP), União Química Brazil, (1, 2 mg/kg) was used as standard.Experimental Protocol The animals were tested during the light period and were observed in a closed room at constant temperature (23Ϯ1°C) and poorly illuminated with a 15-V red light. One hour after the treatment, the open field and rota rod tests were performed with the same animals in the manner described below: Firstly, the animal was placed in the open field area for 5 min. Immediately after the open field test, the animal was removed to the rota rod where it was evaluated for 1 min. All the other tests were performed in different days with other groups of animals. Physiology and Pharmacology, Faculty of Medicine, Fe...

Antidepressant‐like effect of riparin II from Aniba riparia in mice: evidence for the involvement of the monoaminergic system

“…In the present study, our results demonstrate that the acute treatment with riparin II produced a significant antidepressant-like response, evidenced by a decrease in the immobility of animals in both FST and TST. The reduction of this parameter was not accompanied by changes in the locomotor activity assessed in the openfield test in previous study conducted by our group [9]. Taken together, these results suggest that the anti-immobility effect of riparin II cannot be attributable to a psychostimulant effect.…”

“…In a previous study carried out by our group, riparin III exhibited antianxiety and antidepressant activities in mice [8]. Recently, we have reported that riparin II presented antianxiety effect similar to that observed from riparian III in mice treated with the doses of 25 and 50 mg/kg [9]. However, as far as we know, antidepressant‐like properties from riparin II are still unknown in literature.…”

Evidence for the involvement of the serotonergic, noradrenergic, and dopaminergic systems in the antidepressant‐like action of riparin III obtained from Aniba riparia (Nees) Mez (Lauraceae) in mice

“…These results lead to the reduction in intracellular Ca 2+ concentration and possibly contribute to the drug spasmolytic effect [22]. Recently, our group has reported that ripI [23], ripII [24], and ripIII [14,25] present anxiolytic‐like effects in rodent models of anxiety.…”

Central depressant activity of butanol fraction of Securinega virosa root bark in mice

“…The standard agent, diazepam, increased the number of central square crossed without a significant increase in the total ambulation, thus confirming its anxiolytic activity (Sousa et al, 2007).…”