Polar steroid compounds from the Arctic starfish Asterias microdiscus and their cytotoxic properties against normal and tumor cells in vitro

Abstract

Two new natural compounds, sulfated polyhydroxysteroid, microdiscusol G (1), and polyhydroxysteroid bioside, microdiscusoside A (2), along with eight previously known polar steroid substances 3–10, were isolated from the Arctic starfish Asterias microdiscus. The structures of 1 and 2 have been elucidated by extensive 1D and 2D NMR spectroscopy and HRESIMS techniques. The 28-sulfooxy-24-methylcholestane side chain in 1 has been found among starfish steroid metabolites for the first time. Steroid saponins 9 and 10 exhibited cytotoxic effects against normal cells JB6 Cl41 and cancer cells HT-29, MDA-MB-231, THP-1, and Raji and effectively suppressed cell proliferation and colony formation of cancer cells HT-29 and MDA-MB-231 in non-toxic concentrations. Compounds 5, 7, and 8 were inactive or less active in the same experiments.

Keywords:

• Polyhydroxysteroids
• asterosaponins
• starfish
• Asterias microdiscus
• cytotoxicity
• cell proliferation
• clonogenic assay

Acknowledgments

The study was carried out on the equipment of the Collective Facilities Center «The Far Eastern Center for Structural Molecular Research (NMR/MS) PIBOC FEB RAS». The authors are grateful to B.B. Grebnev (G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Vladivostok, Russia) for species identification of the starfish.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The study was partly supported by Grant No. 20-14-00040 from the RSF (Russian Science Foundation).