Alzheimer's disease drug discovery from herbs: neuroprotectivity from beta-amyloid (1-42) insult.

OBJECTIVE To comparatively evaluate selected herbs for their ability to protect neuronal cells from direct betaA(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 betaA(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 betaA(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 (approximately 150 microg/mL), whereas other extracts did not at all protect cells from betaA(1-42) insult. CONCLUSION Selective herbs may be potentially important resources to discover drug candidates against the onset of Alzheimer's disease.