Anthenosides L-U, Steroidal Glycosides with Unusual Structural Features from the Starfish Anthenea aspera

Ten new polyhydroxysteroidal glycosides, anthenosides L-U (1-10), with rare positions of carbohydrate fragment attachments, were isolated from the starfish Anthenea aspera. The structures of 1-10 were established by NMR and ESIMS techniques as well as by chemical transformations. The unoxidized Δ²²-24-nor-cholestane (1), (24S)-Δ²²-24-methylcholestane (2-5), and Δ²²-cholestane (7) side chains of the steroidal aglycons, 3-O-methyl-β-d-galactofuranosyl residue (2, 8), and 5α-cholest-8(14)-ene-3α,7β,16α-trihydroxysteroidal nucleus (9, 10) have not been found previously in starfish polar steroidal compounds. The mixture of glycosides 9 and 10 showed hemolytic activity with an EC₅₀ = 8 μM. Compound 4 at a dose of 10 μM exhibited a potential immunomodulatory action, decreasing by 24% the intracellular ROS content in RAW 264.7 murine macrophages, induced by pro-inflammatory endotoxic lipopolysaccharide from E. coli.