New Pyrrolobenzoxazine Sesquiterpenoid Derivatives from the Fungus Talaromyces trachyspermus

Abstract

Three new pyrrolobenzoxazine sesquiterpenoids, talatrachyoxazines A-C (1-3), together with fourteen known compounds (4-17), were isolated from the fungus Talaromyces trachyspermus EU23. Their structures were identified by spectroscopic evidence and mass spectrometry. The absolute configurations of 1-3 were determined by NOESY data and comparison of their calculated and experimental electronic circular dichroism (ECD) spectra. Compound 1 showed cytotoxic activity against HelaS3, KB, HT-29, MCF-7, and HepG2 cell lines with IC50 values of 7, 11, 10, 12, and 10 μM, respectively. Compounds 1 and 14 showed weak antibacterial activity against the gram-positive bacteria Bacillus cereus and Bacillus subtilis, while 1-3 and 14 showed weak antibacterial activity against the gram-negative bacterium Pseudomonas aeruginosa. In addition, compound 1 showed weak antibacterial activity against Escherichia coli.