Gliovirin-like Alkaloids with Spirocyclic Skeletons from the Mangrove Endophytic Fungus Penicillium janthinellum HDN13-309

To fully explore the metabolites of the mangrove endophytic fungus Penicillium janthinellum HDN13-309, which can produce Epipolythiodioxopiperazine (ETP) compounds with noteworthy anti-tumor activities, HPLC-MS analysis was applied, and five new gliovirin-like alkaloids, penicisulfuranols G–K (1–5), were target-directed acquired. Furthermore, penicisulfuranols G (1) and H (2) were distinguished by a double bond between C-5/C-6 and ortho-hydroxylation of C-7/C-8 on the 1,2-oxazadecaline moiety. Their structures, including absolute configurations, were elucidated based on NMR spectroscopy, ECD measurements, and high-resolution mass spectrometry, as well as by comparison with the literature. Penicisulfuranols I–K (3–5) showed promising cytotoxicity against four tumor cell lines (HCT116, HeLa, HL-60, and K562) with IC50 values ranging from 0.1 to 9.9 μM.