Neuroprotective effect of honokiol and magnolol, compounds from 'Magnolia officinalis', on beta-amyloid-induced toxicity in PC12 cells

Amyloid [beta] peptide (A[beta]) induced toxicity is a well-established pathway of neuronal cell death which might play a role in Alzheimer's disease. In this regard, the toxic effect of A[beta] on a cultured A[beta] -sensitive neuronal cell line was used as a primary screening tool for potential anti-Alzheimer's therapeutic agents. The effects of nine pure compounds (vitamin E, α-asarone, salidroside, baicolin, magnolol, gastrodin, bilobalide, honokiol and [beta]-asarone) from selected Chinese herbs on neuronal cell death induced by A[beta] in NGF-differentiated PC12 cells were examined. Only two of the studied compounds, honokiol and magnolol, significantly decreased A[beta]-induced cell death. Further experiments indicated that their neuroprotective effects are possibly mediated through reduced ROS production as well as suppression of intracellular calcium elevation and inhibition of caspase-3 activity. The results provide for the first time a scientific rationale for the clinical use of honokiol and magnolol in the treatment of Alzheimer's disease.