Neogrisphenol A, a Potential Ovarian Cancer Inhibitor from a New Record Fungus Neohelicosporium griseum

From the rice fermentation product of a new record fungus, , two new polyketides, neogrisphenol A ( ) and neogrisphenol B ( ), one new isochroman-1-one, ( )-6-hydroxy-7-methoxy-3,5-dimethylisochroman-1-one ( ), and four known compounds ( - ) were isolated. Their structures were determined using 1D- and 2D-NMR, mass spectrometry, and chemical calculations. The C-3~C-2' polymerization mode between the two -naphthalenone derivative moieties is uncommon in compounds and . Meanwhile, compounds - and exhibited antibacterial activity against , , , and , with MIC values ranging between 16 and 31 µg/mL. In addition, compound showed antifungal activity against and , with respective IC values of 88.14 ± 2.21 µg/mL and 52.36 ± 1.38 µg/mL. Compound showed significant cytotoxicity against A2780, PC-3, and MBA-MD-231 cell lines with respective IC values of 3.20, 10.68, and 16.30 µM, and the cytotoxicity against A2780 cells was even higher than that of cisplatin (CDDP). With an IC value of 10.13 µM, compound also exhibited cytotoxicity against A2780. The in vitro results showed that compound inhibited A2780 cell proliferation, induced apoptosis, and arrested the cell cycle at the S-phase in a concentration-dependent manner.