Berkeleylactones S-T, novel 16-membered macrolides isolated from the endophytic fungus Penicillium egyptiacum.

The fungus Penicillium egyptacum has been reported as a producer of the 16-membered macrolide antibiotic A26771B. In this study, two new berkeleylactone analogues, berkeleylactones S-T (1-2), were isolated from P. egyptiacum. Their structures were determined by the analyses of 1D- and 2D-NMR data, HRESIMS, and chemical derivatization. 1 is the first example of berkeleylactone analogue possessing a glucose moiety, whose absolute configuration was elucidated by acid hydrolysis followed by derivatization and LC-MS analysis. No antibacterial activity against Bacillus subtilis and Streptococcus salivarius was found within the range of 0-100 μM for compounds 1-2.