In vitro Neuroprotective Activity of Vigna radiata L. and Vigna pilosa L. on Amyloid Beta-induced Cytotoxicity

Background Alzheimer’s disease (AD) is considered to be the most common form of dementia. The drugs that are available for the treatment of AD provide only partial improvement of the condition. In recent years, natural ingredients have received increased attention in generating novel medications for treating various neurological disorders, including AD. Vigna radiata and Vigna pilosa are plants that are routinely included in many Ayurvedic formulations used to manage memory impairment. Objectives The present study was conducted to evaluate the in vitro anticholinesterase and neuroprotective activities of the plants V. radiata and V. pilosa. Materials and Methods A modified 96-well microplate assay according to Ellman’s method was employed to measure acetyl choline esterase (AChE) inhibitory activity. In vitro neuroprotective effect was measured by the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay using the SHSY-5Y (neuroblastoma cells) cell line against β-amyloid induced neurotoxicity. The ethyl acetate extract of V. radiata and the ethanolic extract of V. pilosa, which showed maximum AChE inhibitory activity, were selected for the MTT assay. The cell viability was evaluated by direct observation of cells with the help of an inverted phase contrast microscope, followed by the MTT assay method. Results Maximum AChE inhibitory activity was exhibited by an ethyl acetate extract of V. radiata. It showed AChE activity with a half-maximal inhibitory concentration (IC 50 ) value of 286.40 µg/mL, while the ethanol extract of V. pilosa showed an IC 50 value of 160.19 µg/mL. Extracts of both plants, V. radiata and V. pilosa, significantly ( p ≤ 0.001) improved the percentage of cell viability in a dose-dependent manner. Conclusion The plants V. radiata and V. pilosa showed potent anti-Alzheimer activity when tested using in vitro AChE inhibitory activity and by MTT assay using an β-amyloid-induced in vivo cytotoxicity model. These findings demand the need for further studies using in vivo models.