A new isoalloxazine alkaloid, named bupleurine A (1), along with five known compounds (2-6), were isolated from the aerial parts of Bupleurum chinense DC. The structure elucidation of the new alkaloid (1) was employed by combining NMR and HR-MS data with comparison of reference in the literature. Five known compounds (2-6) were isolated from Bupleurum genus for the first time. Additionally, their antiproliferative activities on HeLa cells were evaluated by MTT assay and IC(50) of compounds 1 and 4-6 were below 10 mum after treatment for 24 h. CI - (c) 2020 Wiley-VHCA AG, Zurich, Switzerland.