Description
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