Calycosin (Cyclosin) is a natural active compound with anti-oxidative and anti-inflammation activity. IC50 value: Target: in vitro: calycosin had obvious anti-proliferation effects on SKOV3 cells in a dose- and time-dependent manner. calycosin up-regulated the Bax/Bcl-2 ratio and cleaved caspase-3, cleaved caspase-9 expression in a dose-dependent manner. In summary, calycosin might exert anti-growth and induce-apoptosis activity against ovarian cancer SKOV3 cells through activating caspases and Bcl-2 family proteins, therefore presenting as a promising therapeutic agent for the treatment of ovarian cancer [1]. Both calycosin and genistein inhibited proliferation and induced apoptosis in MCF-7 breast cancer cells, especially after treatment with calycosin. Treatment of MCF-7 cells with calycosin or genistein resulted in decreased phosphorylation of Akt, and decreased expression of its downstream target, HOTAIR [2]. incubation of calycosin resulted in enhanced expression ERβ in MCF-7 and T-47D cells, rather than MDA-231 and MDA-435 cells. Moreover, with the upregulation of ERβ, successive changes in downstream signaling pathways were found, including inactivation of insulin-like growth factor 1 receptor (IGF-1R), then stimulation of p38 MAPK and suppression of the serine/threonine kinase (Akt), and finally poly(ADP-ribose) polymerase 1 (PARP-1) cleavage [3]. in vivo: calycosin stimulated a dramatic increase in uterine weight and downregulated the level of ERα protein in OVX mice [4].