Alkaloids from Boophane disticha with affinity to the serotonin transporter in rat brain.

Bulbs and leaves of Boophane disticha are used in South African traditional medicine in the treatment of anxiety. Crude extracts of the leaves have shown affinity to the SSRI site on the serotonin transporter in a radioligand binding assay. In this study, two compounds, buphanadrine and buphanamine, were isolated by bioassay-guided fractionation on VLC and preparative TLC. The structures of the compounds were determined by (1)H and (13)C NMR. Fractions were tested for affinity to the serotonin transporter in a binding assay using [(3)H]-citalopram as ligand. The IC(50) values of buphanidrine and buphanamine were 274 microM (K(i)=132 microM) and 1799 microM (K(i)=868 microM), respectively. The two alkaloids were also tested for affinity to the 5HT(1A) receptor, but only showed slight affinity.