The present disclosure relates to a pharmaceutical composition, a health functional food composition, and a method for preventing or treating a brain disease or diabetes. The pharmaceutical composition, health functional food composition, and method includes at least one active ingredient that is chlorhexidine, thioguanosine, mebendazole, fenbendazole, colchicine, farnesol, trimethobenzamide hydrochloride, disulfuram, azathioprine, mebeverine hydrochloride, zaprinast, tosufloxacin hydrochloride, efavirenz, thiostrepton, probenecid, entacapone, harmine hydrochloride, flunisolide, thimerosal, hexestrol, sulfaquinoxaline sodium salt, monensin sodium salt, raloxifene hydrochloride, 2-chloropyrazine, or topotecan.
