Antidepressant and Anxiolytic Effects and Subacute Toxicity of the Aerial Parts of Psychotria ankasensis JBHall (Rubiaceae) in Murine Models

Background. The present study aimed at validating the traditional use and toxicity profile of a methanolic extract of the aerial parts of Psychotria ankasensis in alleviating depression and anxiety disorders. Method. The antidepressant effect of methanolic extract of Psychotria ankasensis (PAE 30, 100, and 300 mg/kg, p.o.) was assessed in mice using the forced swim test (FST) and the tail suspension test (TST). The plant's anxiolytic potential was also evaluated in mice using the elevated plus-maze (EPM) and the open field tests (OFT). The subacute toxicity was assessed via oral administration of PAE at doses of 100, 300, and 1000 mg/kg in rats for 28 days. Results. PAE 100 and 300 mg/kg showed antidepressant-like properties by significantly (at least p<0.05) decreasing the frequency and duration of immobility in FST and TST. PAE (100 and 300 mg/kg) also showed a significant (at least p<0.05) anxiolytic effect in both EPM and OFT. In the EPM test, E-max for PAE and diazepam were 92.52 +/- 40.11% and 85.95 +/- 45.92%, respectively, whereas E-max was approximately 100% for both test drugs in the OFT. Subacute administration of PAE did not reveal any toxic effects with respect to organ weight index, haematological, serum biochemical, and histopathological parameters. Conclusions. Methanolic extract of P. ankasensis exhibited antidepressant-like and anxiolytic-like effects devoid of significant toxicity at the doses tested in murine models.