Pesimquinolones I-S, eleven new quinolone alkaloids produced by Penicillium simplicissimum and their inhibitory activity on NO production

Eleven undescribed quinolone alkaloids, pesimquinolones I-S (1-4 and 6-12), as well as eleven known congeners (5 and 13-22), were isolated from the solid culture broth of the fungus Penicillium simplicissimum. Their chemical structures with absolute configurations were established by a combination of NMR spectroscopy, single-crystal X-ray crystallography, and modified Mosher's methods. Pesimquinolones I-K (1-3) represent the first examples of natural occurring quinolone alkaloids that possess a 6/6/6/6 tetracyclic ring system. The anti-inflammatory activities of selected compounds on LPS-induced nitric oxide (NO) production in adherent cells were evaluated. Compounds 1 and 2 showed suppressive effects on the production of NO, with IC50 values of 10.13 and 8.10 mu M, respectively.

Automated summary

Eleven undescribed quinolone alkaloids, pesimquinolones I-S, as well as eleven known congeners were isolated from the fungus Penicillium simplicissimum. Pesimquinolones I-K are the first examples of natural occurring quinolone alkaloids possessing a 6/6/6/6 tetracyclic ring system. Some compounds showed suppressive effects on LPS-induced NO production, indicating potential anti-inflammatory activities.