PURPOSE: A Paeonia lactiflora seed extract, a fraction thereof, or a compound isolated therefrom, and a pharmaceutical composition containing the same are provided to suppress the activation of beta-secretase (BECE-1) and to prevent or treat neurodegenerative diseases. CONSTITUTION: A pharmaceutical composition for preventing or treating neurodegenerative diseases contains one or more kinds of compounds selected among compounds of chemical formulas 1-8, as active ingredients. A method for preparing the compounds of chemical formulas 1-8 comprises the steps of: adding water, C1-C4 alcohols, or a mixture thereof to Paeonia lactiflora seeds and obtaining a Paeonia lactiflora seed extract； fractioning the extract with water, dichloromethane, and ethyl acetate and obtaining a fraction； and isolating compounds by performing silicagel column chromatography of the fraction and purifying the compounds.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.
