Two New 7/7/6/5-Tetracyclic C25 Steroids From the Marine-Derived Fungus Lodderomyces sp. Z-1.

Lodderomyces is recognized as a yeast genus with important applications in both food fermentation and medical research. In the present study, two new C25 steroids with a 7/7/6/5-tetracyclic scaffold, named (11R,20R)-11-hydroxy-24-oxocyclocitrinol (1) and (11R)-11-hydroxy-erythro-23-O-methylneocyclocitrinol D (2), together with nine known analogues (3-11), were isolated and characterized from the marine-derived fungus Lodderomyces sp. Z-1, which was obtained from the starfish Culcita novaeguineae collected from the South China Sea. The structures and absolute configurations of new compounds were established through extensive spectroscopic analyses, quantum chemical calculations, and comparison of spectral data with those of related analogues reported in the literature. Additionally, the single-crystal x-ray crystallographic structure of the known compound 4 is reported here for the first time. In the anti-inflammatory assay, compound 10 exhibited weak inhibitory activity against LPS-induced NO production in RAW264.7 macrophages with an IC50 value of 41.72 ± 1.81 µM.