A 13,14-seco-13,14-Epoxycholestane and Other Cholestane Derivatives from the Northern Pacific Sea Star Asterias amurensis

The Northern Pacific sea star Asterias amurensis (Asteroidea, Echinodermata), a common species along China’s Yellow Sea coast, has undergone recurrent outbreaks in recent years, with associated ecological and economic impacts. Chemical investigation of specimens collected from the Yellow Sea afforded one new 13,14-seco-13,14-epoxycholestane astamuhemiketal A (1), one new cholestane derivative (20Z)-6α-hydroxy-5α-cholesta-9(11),20(22)-dien-23-one-3β-O-sulfate sodium salt (2), and one new asterosaponin astamurensoside D (5), together with three known cholestanes 24,25-dihydromarthasteron-3-sulfate sodium salt (3), (20E)-6α-hydroxy-5α-cholesta-9(11),20(22)-dien-23-one-3β-O-sulfate sodium salt (4), and 3β-hydroxy-5α-cholest-8-en-7-one (6) from the ethyl acetate extract. Structures were established by comprehensive spectroscopic analyses (1D/2D NMR and HRESIMS), in combination with TDDFT-ECD calculations. This study provides data support for exploring the chemical diversity of secondary metabolites produced by the explosive sea star population in the Yellow Sea and for the subsequent value-added utilization of these substances.