BD is a major active quassinoid in Brucea javanica (L.)Merr., which has anti-cancer properties such as anti-proliferative and pro-apoptotic effects via c-Jun N-terminal kinase (JNK), mitogen-activated protein kinases (MAPK), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of Rapamycin (mTOR), and canonical Wnt signaling pathways against many cancers including BC [33,34]. Here, MAPK8 is linked to breast cancer.