Multifunctionality of Clausena harmandiana Extract and Its Active Constituents against Alzheimer's Disease

This study was designed to investigate the effects of the root-bark extract of Clausena harmandiana (CH) and its active constituents (nordentatin and 7-methoxyheptaphylline) on pharmacological activities regarding selected targets associated with AD, namely, its antioxidant activity, inhibition of A beta aggregation, acetylcholinesterase (AChE) activity, and neuroprotective effects. The effect of the CH extract on the cognitive impairment induced by scopolamine was also evaluated in mice. The effects of the CH extract and its active constituents on radical scavenging, A beta aggregation, and AChE activity were investigated with a 2,2 '-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) assay, a thioflavin-T assay, and Ellman's method. The neuroprotective effects of the extract against hydrogen-peroxide and A beta toxicity were evaluated with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. In addition, the effects on cognitive impairment induced by scopolamine in mice were evaluated using Morris-water-maze and modified-Y-maze test models. The results of the present study demonstrate that the root-bark extract of CH shows multimodal actions relevant to the AD pathological cascade, including antioxidant effects, the inhibition of A beta aggregation, the inhibition of AChE function, and neuroprotection against oxidative stress and A beta toxicity. The extracts could improve both the short- and long-term memory deficits induced by scopolamine in mice.

Automated summary

This study investigates the effects of the root-bark extract of Clausena harmandiana and its active constituents on various pharmacological activities related to Alzheimer's disease. The extract and its compounds show antioxidant effects, inhibit A beta aggregation and AChE function, and provide neuroprotection against oxidative stress and A beta toxicity. Additionally, they improve cognitive impairment induced by scopolamine.