Effect of acute treatment with a water-alcohol extract of Erythrina mulungu on anxiety-related responses in rats

Abstract

We investigated the effect of acute oral treatment with a water-alcohol extract of the inflorescence of Erythrina mulungu (EM, LeguminosaePapilionaceae) (100, 200 and 400 mg/kg) on rats submitted to different anxiety models: the elevated T-maze (for inhibitory avoidance and escape measurements), the light/dark transition, and the cat odor test. These models were selected for their presumed capacity to demonstrate specific subtypes of anxiety disorders as recognized in clinical practice. Treatment with 200 mg/kg EM impaired avoidance latencies (avoidance 1 -200 mg/kg EM: 18 ± 7 s, control group: 40 ± 9 s; avoidance 2 -200 mg/kg EM: 15 ± 4 s, control group: 110.33 ± 38 s) in a way similar to the reference drug diazepam (avoidance 1: 3 ± 0.79 s; avoidance 2: 3 ± 0.76 s), without altering escape. Additionally, the same treatments increased the number of transitions (200 mg/kg EM: 6.33 ± 0.90, diazepam: 10 ± 1.54, control group: 2.78 ± 0.60) between the two compartments and the time spent in the lighted compartment in the light/dark transition model (200 mg/kg EM: 39 ± 7 s; diazepam: 61 ± 9 s; control group: 14 ± 4 s). The dose of 400 mg/kg EM also increased this last measurement (38 ± 8 s). These results were not due to motor alterations since no significant effects were detected in the number of crossings or rearings in the arena. Furthermore, neither EM nor diazepam altered the behavioral responses of rats to a cloth impregnated with cat odor. These observations suggest that EM exerts anxiolytic-like effects on a specific subset of defensive behaviors, particularly those that have been shown to be sensitive to low doses of benzodiazepines.

Effects of Chronic Treatment with a Water-Alcohol Extract from Erythrina mulungu on Anxiety-Related Responses in Rats

“…16) The absence of significant results with EM or DZP in the cat odor test agrees with previous data obtained in our laboratory after acute treatment with the compounds. 10) Measurements performed in the cat odor test appear to be resistant to numerous pharmacologic treatments leading to the proposition that the model is representative of phobic disorders. [20][21][22] Anxiolytic effects of EM in ETM inhibitory avoidance and in the light/dark transition model were also seen after the acute administration of the extract.…”

“…[20][21][22] Anxiolytic effects of EM in ETM inhibitory avoidance and in the light/dark transition model were also seen after the acute administration of the extract. 10) Since both the inhibitory avoidance task and the measurements performed in the light/dark transition model have been related in terms of psychopathology to generalized anxiety, we previously suggested that EM would most likely have therapeutic benefit in this subtype of anxiety disorder. It was further hypothesized that this selective effect of EM was possibly related to the mechanism of action of some of its constituents, i.e., alkaloids.…”

“…2) Recently, the supposed therapeutic properties of EM have begun to be evaluated in preclinical studies. Thus, in a previous study performed in our laboratory, 10) the effects of acute treatment with a water-alcohol extract from the inflorescence of EM were investigated in rats submitted to models specifically related to different types of anxiety disorder: the elevated T-maze (ETM), the light/dark transition, and the cat odor test. Results showed that acute treatment with EM altered both inhibitory avoidance latencies in the ETM and the behavior of rats in the light/dark transition model, in a way similar to DZP.…”

Ansiedade: aspectos gerais e tratamento com enfoque nas plantas com potencial ansiolítico

“…Além disso, tanto no tratamento agudo (ONUSIC et al, 2002), quanto no tratamento crônico (ONUSIC et al, 2003), o extrato hidroalcoólico da inflorescência de E. mulungu, mostrou efeito ansiolítico, relacionado com um comportamento defensivo, associado ao tratamento da ansiedade generalizada (SOUSA et al, 2008).…”

Seed Germination and Production of <i>Erythrina mulungu</i> and <i>Erythrina velutina</i> Plantlets

“…The sedative action of the Erythrina tea that is popularly consumed in Brazil has been reported in ethnobotanical studies [6] [7]. Moreover, numerous pharmacological studies carried out with animals validated the anxiolytic, anticonvulsant and antinociceptive effects of the hydroalcoholic extract of E. velutina and E. mulungu stem bark and flowers [8]- [17] However, even being a species relevant to the development of scientific researches, especially considering its diversity of use and validated therapeutic efficacy, only a few studies on Erythrina seed germination characteristics and production of seedlings have been carried out and those works are restricted to seed physical dormancy caused by its water-impermeable seed coat [18]- [21].…”