Effects of South Africa traditional medicine in animal models of depression

In the search for new therapeutics for the treatment of depression, ethanolic extracts from South African medicinal plants Agapanthus campanulatus F.M. Leighton (Alliaceae) (AC), Boophane distica (L.f.) herb (Amarylliaceae), (BD), Mondia whitei (Hook.f.) Skeels (Asclepiadeace) (MW) and Xysmalobium undulatum (L.) Aiton.f. (Asclepiadeace) (XU) used in traditional medicine to treat mental illnesses related to depression were investigated. Extracts were tested in in vitro and in vivo models for depression. The extracts were screened for affinity for the serotonin transporter (SERT) in the [³H]-citalopram binding assay. Functional characterization of the extracts was conducted using cloned human SERT, norepinephrine uptake (NET) and dopamineuptake (DAT). Antidepressant-like effects of the extracts were investigated using the tail suspension test (TST) and the forced swim test in both rats (rFST) and mice (mFST). All four plants showed affinity for SERT in the binding assay (figure 1). AC and BD showed functional inhibition of SERT, NET and DAT while MW affected SERT and XU showed no effect. BD showed significant effect in the TST (125mg/kg) and in the rFST/mFST (250–500mg/kg), AC showed significant effect in mFST (250–500mg/kg), MW showed significant effect in the rFST (250mg/kg) and XU showed significant effect in the mFST (250–500mg/kg). In conclusion, all four plants exhibited in vitro and in vivo antidepressant-like effects, which supports their traditional use.

Fig.1. AC: squares; BD: circles; MW: triangles; XU: diamonds