Abstract:
Alzheimer's disease (AD) is the most common type of dementia in the aging population. Enhancement of acetylcholine levels in the brain is
one means of treating the disease. However, the drugs presently used in the management of the disease have various drawbacks. New treatments
are required and in this study, extracts of Salvia tiliifolia Vahl. (whole plant), Chamaecrista mimosoides L. Greene (roots), Buddleja salviifolia
(L.) Lam. (whole plant) and Schotia brachypetala Sond. (root and bark) were evaluated to determine their polyphenolic content, antioxidant and
acetylcholinesterase inhibitory (AChEI) activity. The DPPH and ABTS assays were used to determine antioxidant activity and Ellman
colorimetric method to quantify AChEI activity. Although all four plants showed activity in both assays, the organic extracts of C. mimosoides
root was found to contain the highest AChEI activity (IC50=0.03±0.08 mg/ml) and B. salviifolia whole plant had the highest antioxidant activity
(ABTS; IC50=0.14±0.08 mg/ml and DPPH; IC50=0.23±0.01 mg/ml). The results suggest that the tested plant species may provide a substantial
source of secondary metabolites, which act as natural antioxidants and acetylcholinesterase inhibitors, and may be beneficial in the treatment of
AD.
