Boerechalasins A–G, cytochalasans from the fungus Boeremia exigua with anti-inflammatory and cytotoxic activities.

Seven previously undescribed cytochalasans, namely, boerechalasins A–G, together with one analogue, were characterized from the solid culture of the fungus Boeremia exigua. Their structures and absolute configurations were elucidated on the basis of extensive spectroscopic analysis as well as electronic circular dichroism calculations. Remarkably, boerechalasin F possessed an unusual sulfoxide moiety that might be derived from methionine, while boerechalasin G had an unusual 5-methylcyclohexane-1,2,3-triol substituent at N-2 position. Boerechalasins A and E exhibited inhibitory activities against nitric oxide production in LPS-induced RAW264.7 macrophages with IC 50 values of 21.9 and 5.7 μM, respectively. Boerechalasin F displayed cytotoxicity against human MCF‒7 cells with an IC 50 value of 22.8 μM. Eight previously unreported cytochasans have been isolated from the fungus Boeremia exigua. Some of them exhibited anti-inflammatory activity or cytotoxicity. [Display omitted] • Seven previously undescribed cytochalasans were isolated from Boeremia exigua. • Compound 6 represented the first example of cytochalasan originated from methionine. • Compound 7 contained an interesting 5-methylcyclohexane-1,2,3-triol substituent. • Two compounds displayed anti-inflammatory activity. • One compound displayed cytotoxicity. [ABSTRACT FROM AUTHOR]