A new class of dimeric product isolated from the fungus Chaetomium globosum: evaluation of chemical structure and biological activity.

Chaetomium globosum is a filamentous fungus from which we have previously isolated a series of interesting natural products. Here, we isolated a previously unknown natural product from the culture of C. globosum. Through spectroscopic and crystallographic characterization, we determined the compound to be a new dimerized azaphilone-type product which we termed cochliodone J (1). Furthermore, our investigation into the biological activity of the natural product determined that 1 was cytotoxic to human cervix carcinoma HeLa cells with an IC50 of 17.3 µM. Lastly, a plausible biosynthetic mechanism for 1 is suggested based on our previous study on the biosynthesis of a closely related compound, cochliodone A (2).