Folipastatin

Four new di-Ph ethers, aspergillusethers G-J (1-4), and one new depsidone, emeguisin D (7), together with eighteen known compounds have been isolated and characterized from the endophytic fungus Aspergillus unguis BCC54176.The chem. structures were established based on spectroscopic evidence in conjunction with a chem. transformation.Furthermore, the chem. structure of compound 7 was verified by single-crystal X-ray diffraction data.The isolated compounds were evaluated for biol. activity.Compound 7, emeguisin C (10), and nidulin (14) showed antibacterial activity against Bacillus cereus with an equal MIC value of 1.56μg/mL, while emeguisin A (8), nornidulin (13), 2-chlorounguinol (16), and aspergillusidone C (21) displayed anti-phytopathogenic activity against Colletotrichum acutatum with the equal MIC value of 3.13μg/mL.Compound 7 was also active against Staphylococcus aureus with an MIC value of 1.56μg/mL.However, none of the tested compounds had cytotoxicity against cancerous (MCF-7 and NCI-H187) and non-cancerous (Vero) cells.

Seven new polyketides including a phenol (1), two diphenyl ethers (2 and 3), two depsidones (4 and 5), and two phthalides (6 and 7) were isolated from the fungus Aspergillus unguis PSU-MF16 along with 27 known compounds. Their structures were determined by extensive spectroscopic analysis. The absolute configurations of 1 and 4-7 were established using comparative analyses of calculated and experimental ECD spectra. Among the new metabolites, 2 exhibited the best antimicrobial activity against Staphylococcus aureus, methicillin-resistant S. aureus, and Microsporum gypseum with equal MIC values of 16 μg/mL. In addition, known emeguisin A displayed potent antimicrobial activity against S. aureus, methicillin-resistant S. aureus, and Cryptococcus neoformans with equal MIC values of 0.5 μg/mL, compared with the standard drugs, vancomycin and amphotericin B. The structure-activity relationship study of the isolated compounds for antimicrobial activity is discussed.