Activity of traditional South African sedative and potentially CNS-acting plants in the GABA-benzodiazepine receptor assay.

Several plants are traditionally used to treat mental diseases in South Africa. Forty-six ethanol extracts from 35 species, both indigenous and exotic that are traditionally used predominantly as sedatives or to treat various CNS-related ailments were tested in the GABAA-benzodiazepine receptor-binding assay. In this assay, the binding of 3H-Ro 15-1788 (flumazenil) to the benzodiazepine site is measured. The GABAA-benzodiazepine receptor complex is involved in sedation, epilepsy and convulsions. Out of the 46 extracts tested, seven showed good activity and 10 showed moderate activity. The most active extracts were the ethanolic leaf extracts of Arctopus echinatus, Artemisa afra, four Helichrysum species and Mentha aquatica which all showed good dose-dependent activity.