β-Bisabolene is a sesquiterpene natural product exhibiting cytotoxicity towards breast cancer cell lines, inducing apoptosis in MCF-10A, MDA-MB-231, and BT474 cells.

β-Bisabolene exhibits selective cytotoxicity: for murine cells, the half-maximal inhibitory concentration (IC₅₀) is >200 μg/ml for normal cells Eph4, 65.49 μg/ml for breast cancer cells MG1361, and 48.99 μg/ml for breast cancer cells 4T1; for Homo sapiens breast cancer cells, the IC₅₀ is 114.3 μg/ml for normal mammary epithelial cells MCF-10A, 66.91 μg/ml for breast cancer cells MCF-7, 98.39 μg/ml for breast cancer cells MDA-MB-231, 70.62 μg/ml for breast cancer cells SKBR3, and 74.3 μg/ml for breast cancer cells BT474. [1]

In vivo experiments demonstrated that β-Bisabolene effectively inhibited the growth of transplanted 4T1 mammary tumors, reducing tumor volume by 37.5% at the experimental endpoint. [1]