Cytoglobosins H and I, New Antiproliferative Cytochalasans from Deep-Sea-Derived Fungus Chaetomium globosum.

Cytoglobosins H (1) and I (2), together with seven known cytochalasan alkaloids (3-9), were isolated from the deep-sea-derived fungus Chaetomium globosum. The structures of new compounds 1 and 2 were elucidated by extensive 1D and 2D NMR and mass spectroscopic data. All the compounds were evaluated for their antiproliferative activities against MDA-MB-231 human breast cancer cells, LNCaP human prostate cancer cells, and B16F10 mouse melanoma cells. Compound 6 showed significant antiproliferative activity against LNCaP and B16F10 cell lines with IC50 values of 0.62 and 2.78 μM, respectively. Further testing confirmed that compound 6 inhibited the growth of LNCaP cells by inducing apoptosis.