Isolation, structure elucidation, and biological evaluation of the unusual heterodimer chrysoxanthone from the ascomycete IBWF11-95A

Chrysoxanthone, an unusual heterodimer of blennolide A and 2-hydroxychrysophanol linked through a diaryl ether bridge, was isolated from mycelia of the ascomycete IBWF11-95A grown in submerged culture. Its structure was elucidated by two-dimensional NMR spectroscopy. The metabolite shows antibacterial activity against different species with MIC values between 2.5 and 20 μg/mL while also inhibiting the growth of several fungi.