卡萨霉素B 是瘦链霉菌素复合物的次要成分，该复合物是由a.Streptomyces sp。|的肉汤发酵产生的。该化合物是Leptomycin A的羟基化类似物，它是一种核输出抑制剂，且具有高度亲脂性。| 卡萨霉素B 对肿瘤L1210，P388 / S，B16，HeLa S3，L5178Y-ML或当在卡祖霉素B存在下培养72小时时，确定L929的IC 50为1.8、2.0、0.7、1.8、10.0和1.0ng / ml。该化合物在小鼠中还表现出广泛的抗肿瘤活性，其有效性比体内和体外给药浓度更依赖于给药方案。 Kazusamycin B is a minor component of the leptomycin complex produced from the fermentation of the broth of a|Streptomyces sp.|. The compound is a hydroxylated analogue of Leptomycin A , a nuclear export inhibitor, and highly lipophillic.|In vitro|antitumor activity of Kazusamycin B on tumors L1210, P388/S, B16, HeLa S3, L5178Y-ML or L929 was ascertained to have an IC|50|of 1.8, 2.0, 0.7, 1.8, 10.0 and l.0 ng/ml when cultured in the presence of Kazusamycin B for 72 hours. The compound has also displayed broad antitumor activity in mice with effectiveness being more dependent on dosing regimen than dosing concentration both|in vivo|and|in vitro|. Kazusamycin B also possesses antibacterial and antifungal activity.