Themajority of the population in South Africa use traditional health care to treat various mental conditions.
In this review, we present ethnobotanical information on plants used by the traditional healers in South
Africa to treat mental illnesses, specifically epilepsy, depression, age-related dementia and debilitative
mental disorders. Details of the recent scientific studies conducted on some of these plants are reviewed.
Extracts of Searsia chirindensis, Cotelydon orbiculata and Leonotis leonurus have shown in vivo anticonvulsant
activity. Extracts from Searsia dentata and Searsia pyroides showed spontaneous epileptiform
discharge in mouse cortical slices, and acted asNMDA-receptor antagonists. Apigenin, amentoflavone and
agathisflavone with affinity to the benzodiazepine site on the GABAA-receptor were isolated from Searsia
pyroides. Naringenin with affinity to the GABAA-benzodiazepine receptor was isolated from Mentha
aquatica.
Agapanthus campanulatus, Boophone disticha, Mondia whitei and Xysmalobium undulatum exhibited
antidepressant-like activity in three in vivo models for depression. Amaryllidaceae alkaloids with activity
to the serotonin transporter were isolated from Boophone disticha. The alkaloid mesembrine, which act as
a serotonin reuptake inhibitor, was isolated from Sceletium tortuosum.
Investigations of plants used to treat age-related dementia and debilitative mental disorders lead to
the isolation of a number of Amaryllidaceae alkaloids with acetylcholinesterase inhibitory activity from
Boophone disticha and Crinum species. Extracts of Mentha aquatica, Gasteria croucheri, Ruta graveolens and
Scotia brachypetala inhibited MAO-B. Naringenin was isolated from Mentha aquatica as a MAO inhibitor.
Only a small number of the more than 300 southern African plant species reported to treat or affect
the CNS have been scientifically evaluated. Very few of the active compounds have been isolated and
identified.