Two new alkaloids from Penicillium oxalicum EN-201, an endophytic fungus derived from the marine mangrove plant Rhizophora stylosa

- Penicillium oxalicum EN-201, an endophyte of mangrove Rhizophora stylosa, was studied.
- Two new alkaloids, penioxamide A (1) and 18-hydroxydecaturin B (2), were identified.
- Compounds 1 and 2 showed potent brine shrimp lethality against Artemia salina.

Two new alkaloids including a new prenylated indole derivative possessing a piperidine moiety, penioxamide A (1), and a new decaturin analogue, 18-hydroxydecaturin B (2), were isolated and identified from Penicillium oxalicum EN-201, an endophytic fungus obtained from the inner tissue of the fresh leaves of marine mangrove plant Rhizophora stylosa. Their structures and absolute configurations were elucidated on the basis of the spectral data and CD analysis. Compound 1 bears the rare anti relative configuration in the bicyclo[2.2.2]diazaoctane ring, while compound 2 has a pyridinyl-α-pyrone substructure which is rare among natural products. Compounds 1 and 2 showed potent brine shrimp lethality with LD50 values of 5.6 and 2.3 μM, respectively.