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.
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