Acetylcholinesterase inhibitory activity of plants used as memory- enhancers in traditional South African medicine

In traditional South African medicine there are a few plants used to improve memory and to treat Alzheimer's disease. Aqueous and ethanol extracts of five of these plants: Malva parviflora (leaves), Boophane disticha (leaves and bulbs), Albizia adianthifolia (stem bark), Albizia suluensis (root bark) and Crinum moorei (bulbs) were investigated. They were screened for acetylcholinesterase (AChE) inhibiting activity using thin- layer chromatography (TLC) and microtitre plate assays. Inhibition of AChE is an important approach in treating Alzheimer's disease. Promising results were obtained with bulbs of B. disticha and C. moorei. The aqueous and ethanol extracts of B. disticha (0.1mgml−1) yielded 38% and 27% inhibition in the microplate assay, respectively, while the ethanol extract of C. moorei had good dose-dependent inhibiting activity with 67% inhibition at the highest concentration. Aqueous and ethanol extracts of C. moorei and B. disticha showed AChE inhibiting activity in the TLC assay