Antiplasmodial, GABAA-benzodiazepine receptor binding and acetylcholinesterase inhibitory activities of plants used in traditional medicine in Mali, West Africa

Abstract

The recourse to traditional medicine and medicinal plants could be an alternative to expensive synthetic drugs for developing countries. Malaria is the leading cause of morbidity and mortality in Mali. Plants used in traditional medicine for treatment of epilepsy and convulsions are potential sources to look into in order to find substances that enhance GABA's affinity to the GABAA-receptor. An important approach in the symptomatic treatment of Alzheimer's disease (AD) involves the inhibition of acetylcholinesterase. Five medicinal plants: Boscia angustifolia A. Rich, Cissus quadrangularis L., Securidaca longepedunculata Fers, Stylosanthes erecta P. Beauv. and Trichilia emetica Vahl., used traditionally in Mali to treat malaria, old age-related memory loss, epilepsy and convulsion have been evaluated for their antiplasmodial activities, their ability to bind to the GABAA-benzodiazepine receptor [1] and acetylcholinesterase inhibitory activity on the TLC assay [2]. The strongest antiplasmodial activity was observed with dichloromethane extracts of leaf of S. longepedunculata with IC50 of 7µg/mL (95% CI: 5–9) and leaf of T. emetica IC50: 12µg/mL (95% CI: 12–14). The strongest binding to GABAA-receptor was obtained with the methanol extract of aerial part of S. erecta. No acetylcholinesterase inhibitory activity in the TLC assay was observed with any of the tested extracts. The GABAA-benzodiazepine receptor assay results suggest that the active compounds are of apolar nature. The results of this study justify some of the traditional indications of the plants investigated.