Two New Steroidal Monoglycosides, Anthenosides A(1) and A(2), and Revision of the Structure of Known Anthenoside A with Unusual Monosaccharide Residue from the Starfish Anthenea aspera

Two new polyhydroxysteroidal glycosides, anthenosides A(1) (1) and A(2) (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-β-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%.