Cytotoxic Dibohemamines D–F from a <i>Streptomyces</i> Species

Three dimeric analogues of bohemamines, dibohemamines D–F (<b>1</b>–<b>3</b>), together with dibohemamine A (<b>4</b>), were isolated from <i>Streptomyces</i> sp. CPCC 200497. Their structures were solved using a combination of mass spectrometry, 1D and 2D NMR spectroscopy, and CD. Dibohemamines D and E were new dimeric analogues of bohemamines, and dibohemamine F was a known compound obtained previously by semisynthesis. Dibohemamine F displayed potent cytotoxicity against cancer cell lines A549 and HepG2 with IC<sub>50</sub> values of 1.1 and 0.3 μM, respectively. Dibohemamines D and E showed moderate cytotoxicity against cancer cell lines A549 and HepG2.