A new diphenyl ether from the endophytic fungus Verticillium sp. isolated from Rehmannia glutinosa

To investigate the chemical constituents of the endophytic fungus Verticillium sp. isolated from Rehmannia glutinosa.

The compounds were isolated and purified by repeated column chromatography, and their structures were determined on the basis of physicochemical properties and spectral analysis. Their cytotoxic and antifungal activities were evaluated.

Ten compounds were obtained and their structures were identified as 2, 4-dihydroxy-2', 6-diacetoxy-3'-methoxy-5'-methyl-diphenyl ether (1), paecilospirone (2), α-acetylorcinol (3), 2-methoxy-1,8-dimethyl-xanthen-9-one (4), 4-hydroxy-α-lapachone (5), enalin A (6), 2,3,4-trimethyl-5,7-dihydroxy-2,3-dihydrobenzofuran (7), 4-hydroxyethyl-phenol (8), 2,4-dihydroxy-3,5,6-trimethyl- methylbenzoate (9), and 3-isopropenyl-(Z)-monomethyl maleate (10).

Compound 1 is a new diphenyl ether, and showed cytotoxic activity against HL-60 cells (IC50 2.24 μg · mL(-1)), and antifungal activities against Candida albicans (MIC 8 μg · mL(-1)) and Aspergillus fumigatus (MIC 16 μg · mL(-1)).