Two New Steroidal Monoglycosides, Anthenosides A1 and A2, and Revision of the Structure of Known Anthenoside A with Unusual Monosaccharide Residue from the Starfish Anthenea aspera.

Two new polyhydroxysteroidal glycosides, anthenosides A1 (1) and A2 (2), and one previously known steroidal glycoside anthenoside A (3) were isolated from extract of the tropical starfish Anthenea aspera. Structures of 1⁻3 were determined by analysis of the spectroscopic data as well as chemical transformations. As a result, the structure of anthenoside A has been revised and the structures of 1 and 2 were established. Glycosides 1⁻3 contain a 2-acetamido-2-deoxy-4-O-methyl-ß-d-glucopyranosyl residue, found in the starfish steroidal glycosides for the first time. All the isolated compounds slightly inhibited cell viability of human cancer T-47D cells and did not show cytotoxic effects against RPMI-7951 cells. Glycoside 1 slightly inhibited colony formation of human cancer RPMI-7951 cells by 16% while compound 2 decreased the number of colonies of T-47D cells by 40%.

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-ß-d-galactofuranosyl residue (2, 8), and 5α-cholest-8(14)-ene-3α,7ß,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.

Synaptosides A and A1, triterpene glycosides from the sea cucumber Synapta maculata containing 3-O-methylglucuronic acid and their cytotoxic activity against tumor cells.

Two novel triterpene holostane glycosides, synaptosides A ( 1) and A 1 ( 2), have been isolated from the Vietnamese sea cucumber Synapta maculata (Synaptida, Apodida). Their structures were elucidated by spectroscopic methods (NMR and MS) and chemical transformations. Glycosides 1 and 2 have rare branched pentasaccharide carbohydrate chains featuring a 3- O-methylglucuronic acid residue not previously reported in glycosides from sea cucumbers and a 6- O-sulfated glucose. Glycoside 2 has an oxo group at C-7 and a 8(9)-double bond. All these structural features are unknown in glycosides from sea cucumbers. Glycoside 1 has moderate cytotoxic activity (IC 50 8.6 microg/mL) and glycoside 2 is inactive against HeLa tumor cells.