Anxiolytic-like effects of Brickellia cavanillesii and their bioactive compounds nicotiflorin and acacetin in experimental models in mice

Anxiety disorders are one of the most prevalent classes of mental disorders among people of all ages [1]. Currently drugs for controlling anxiety have many adverse side effects; however, medicines from plant sources have played a vital role as an alternative treatment. In this context there are individual testimonies about the use of Brickellia cavanillesii (Cass.) A. Gray (Asteraceae) to treat anxiety [2,3]. Despite its use as a tranquilizer, there are no formal studies demonstrating the anxiolytic effect of this plant and the possible responsible bioactive compounds. Pharmacological evidence of the central nervous system effects of B. cavanillesii is introduced. A methanol extract from B. cavanillesii (MEBc) was evaluated in several experimental models of anxiety and sedation; diazepam (0.1 mg/kg) was used as a positive control, and vehicle as a negative control. Ambulatory activity (open-field-test) of mice was significantly decreased in the presence of different doses (1 to 100 mg/kg, i.p.) of MEBc. A similar profile was observed in the hole-board test, where significant diminution in head dips was obtained at all doses. Sedative-like effects were determined in mice on cylinder exploration and elevated plus-maze test, with significant activity only at 30 and 100 mg/kg doses. A phytochemical study of the methanol extract allowed us to isolate two major compounds nicotiflorin and acacetin, which were identified by 1D and 2D NMR experiments. A decrease in ambulatory activity (open-field-test), diminution in head dips in hole-board test, and a reduction of the exploratory rearing on a cylinder of explorations test were significantly decreased by acacetin in a dose-dependent manner. Both compounds presented significant activity when tested in elevated plus-maze indicating anti-anxiety response. In conclusion, the overall results provide data that support the anxiolytic-like effect of B. cavanillesii and the metabolites acacetin and nicotiflorin.

Keywords: Brickellia cavanillesii, acacetin, nicotiflorin, anxiolytic-like effect.

References:

[1] Kessler RC, Berglund P, Demler O, Jin R, Merikangas KR, Walters EE. Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry 2005; 62: 593 – 602

[2] Monroy OC, Castillo EP. Plantas medicinales utilizadas en el estado de Morelos. Cuernavaca, Mor. Universidad Autónoma del Estado de Morelos, 2007

[3] Eshiet E, Zhu J, Smith EE. Lyophilized tea extracts of Brickellia cavanillesii (Asteraceae): in vitro characterization of biological activity. J Food Sci 2014; 79: 1454 – 1461