Alzheimer's Disease Drug Discovery from Herbs: Neuroprotectivity from β-Amyloid (1-42) Insult

Objective: To comparatively evaluate selected herbs for their ability to protect neuronal cells from direct βA(1-42) insult. Design: Twenty-seven (27) herbs were selected, extracted with aqueous methanol (90%) and chloroform, and the extracts were evaluated for their ability to protect PC12 rat pheochromocytoma and primary neuronal cells from βA(1-42) insult using both 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide reduction assay and lactate dehydrogenase efflux assay. Results: Curcuma aromatia (ul-keum) and Zingiber officinale (ginger) extracts effectively protected cells from βA(1-42) insult, followed by Ginkgo biloba (ginkgo), Polygonatum sp. (King Solomon's seal), Cinnamum cassia (Chinese cinnamon), Rheum coreanum (Korean rhubarb), Gastrodia elata (gastrodia), and Scutellaria baicalensis (skullcap). Several extracts showed cytotoxicity at high concentration (∼150 μg/mL), whereas other extracts did not at all protect cells from βA(1-42) insult. Conclusion: Selective herbs may be potentially important resources to discover drug candidates against the onset of Alzheimer's disease.