Three alkaloids were isolated from the aerial parts of Gnaphalium polycaulon Pers., Asteraceae, collected from San Juan Huancollo, Ingavi Province, La Paz, Bolivia. The chemical structures of these compounds were elucidated through NMR and HRMS spectroscopic analyses as 2-[4-(1H-tetrazol-1-yl)phenyl]-2-aminopropanoic acid, N-phenyl-4-(3-phenyl-1,2,4-thiadiazol-5-yl)piperazine-1-carboxamide, and N-(4-ethoxyphenyl)-4-(2-methylimidazo[1,2-alpha]pyridin-3-yl)thiazol-2-amine. All compounds showed in vitro anti-Alzheimer activity at concentrations of 44.24 +/- 0.15 mu M, 0.016 +/- 0.002 mu M. and 0.0073 +/- 0.0002 mu M, respectively. This pharmacological potential was higher than that of the positive controls, galantamine (11.70 +/- 0.17 mu M), and curcumin (10 +/- 0.14 mu M).