beta-Amyloid peptide (Abeta) is the main protein components of neuritic plaques and its neurotoxicity would be exposed by formation of aggregate. The aggregation inhibitors composed of an Abeta recognition element (KLVFF) and a flexible hydrophilic disrupting element (aminoethoxy ethoxy acetate and aspartate) are designed and chemically synthesized. The inhibitory effects are examined by a pigment binding assay using Congo red or thioflavin T. The present compounds suppress the formation of aggregate, and the compound DDX3 is an especially effective inhibitor. In addition, the synthesized compounds efficiently suppress the cytotoxicity of Abeta against IMR-32 neuroblastoma cells in vitro. (C) 2002 Elsevier Science.