ABSTRACT The combination of 1 H‐nuclear magnetic resonance‐based metabolomics tracking coupled with ultraviolet analysis facilitated the targeted isolation of ten meroterpenoids ( 1–10 ), including three previously undescribed ones ( 1 , 2 , and 5 ), from the culture broth of an endophytic fungus, Penicillium oxalicum . The chemical structures of these meroterpenoids were elucidated based on comprehensive spectroscopic analysis and mass spectrometry. All isolates were identified as members of the decaturins/oxalicines family, which features a naturally unique pyridinyl‐α‐pyrone polyketide subunit. To facilitate the development of novel antitumor agents, the in vitro cytotoxic activities of all isolates were evaluated. MTT assay results revealed that compounds 1 – 5 , 9 , and 10 exhibited weak to moderate cytotoxic effects against tumor cell lines, with half‐maximal inhibitory concentration values from 8.74 ± 1.09 to 39.92 ± 0.47 µM, respectively.
Wu et al. (2026) studied this question.