PURPOSE: A compound having an activity of suppressing tyrosinase, isolated from Lespedeza cyrtobotrya MIQ is provided to suppress tyrosinase and to be used as a melanogenesis inhibitor. CONSTITUTION: A cosmetic composition for skin whitening contains 0.05-10.0 weight% of compound of chemical formula 1. The composition suppresses tyrosinase. The composition is used in the form of lotion, cream, essence, cleansing foam, cleansing water, pack, body lotion, body oil, body gel, foundation, or makeup base. A method for isolating the compound from Lespedeza cyrtobotrya MIQ comprises: a step of refluxing Lespedeza cyrtobotrya MIQ with methanol and filtering to obtain methanol extract； a step of suspending the methanol extract into distilled water and shaking with ethyl acetate to obtain an ethyl acetate soluble part； a step of dissolving the ethyl acetate soluble apart in a small amount of methanol； a step of performing gel filtration chromatography to obtain an active fraction； and a step of performing HPLC(High Performance Liquid Chromatography) to obtain a single pre compound.본 발명은 콩과 식물의 일종인 참싸리(Lespedeza cyrtobotryaMIQ)로부터 분리한 타이로시네이즈 저해활성을 가지는 화합물에 관한 것으로서, 더욱 상세하게는 참싸리의 메타놀(methanol) 추출액 중 에틸아세테이트(ethyl acetate) 가용부를 분리하여 젤여과크로마토그래피(gel filtration chromatography)를 통해 단리 된 화학식1로 표시되는 화합물 및 그를 포함하는 타이로시네이즈 저해제로 사용하는 용도에 관한 것이다. 이러한 화합물이 타이로시네이즈 저해효과를 나타내므로 멜라닌 생합성 저해제로 이용될 수 있다.
