PURPOSE: A pharmaceutical composition containing Paeonia lactiflora seed extract, fraction thereof, or compound isolated from the same is provided to suppress BACE-1 activity and to treat and prevent neurodegenerative diseases. CONSTITUTION: A pharmaceutical composition for preventing or treating neurodegenerative diseases contains Paeonia lactiflora seed extract as an active ingredient. The neurodegenerative diseases include Alzheimer's dieses, Parkinsons's disease, progressive supranuclear palsy. The extract is prepared using water, alcohol of C1-C4, or mixture solvent thereof. The pharmaceutical composition contains Paeonia lactiflora seed fraction as an active ingredient. The pharmaceutical composition also contains compounds as an active ingredient. The method for preparing the compounds comprises: a step of adding water, C1-C3 alcohol, or mixture thereof to the Paeonia lactiflora seeds to prepare Paeonia lactiflora seed extract； a step of fractioning the extract with water, dichloromethane, and ethyl acetate to prepare a fraction； a step of performing silicagel column chromatography of the fraction.본 발명에 따른 작약 종자의 추출물, 이의 분획물 또는 이로부터 분리한 화합물은 BACE-1 활성을 저해시켜 알츠하이머형 치매, 파킨슨 병, 진행성 핵상마비 등 퇴행성 뇌질환의 예방 또는 치료에 유용하게 사용될 수 있다.
