One new ten-membered macrolide and one new pyridinone derivative from the mangrove endophytic fungus <i>Alternaria porri #</i> 25

One new ten-membered macrolide derivative, porriolide (<b>1</b>), and one new 2(1H)-pyridinone derivative (±)-porripyridone (<b>2</b>), together with seven known compounds alternariol 4-methyl ether (<b>3</b>), alternariol (<b>4</b>), 5'-methoxy-6-methylbiphenyl-3,4,3'-triol (<b>5</b>), altenusinoide A (<b>6</b>), harziano pyridone (<b>7</b>), penicilloxalone A (<b>8</b>), and cytosporin D (<b>9</b>) were obtained from mangrove endophytic fungus <i>Alternaria porri</i> #25. Their structures were elucidated using comprehensive spectroscopic methods, and the absolute configuration of the new compounds were further confirmed by ECD spectra and single-crystal X-ray diffraction analysis, respectively. Compounds <b>2</b> and <b>7</b> exhibited cytotoxic activities against prostate cancer VCap and PC-3 cells with IC₅₀ values ranging from 22.94 ± 0.53 μmol/L to 38.13 ± 0.93 μmol/L, while compound <b>1</b> showed no cytotoxic activity.