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.