Rare Ophiuroid-Type Steroid 3β,21-, 3β,22-, and 3α,22-Disulfates from the Slime Sea Star Pteraster marsippus and Their Colony-Inhibiting Effects against Human Breast Cancer Cells.

Two new steroid 3β,21-disulfates ( 1 , 2 ) and two new steroid 3β,22- and 3α,22-disulfates ( 3 , 4 ), along with the previously known monoamine alkaloid tryptamine ( 5 ) were found in the ethanolic extract of the Far Eastern slime sea star Pteraster marsippus . Their structures were determined on the basis of detailed analysis of one-dimensional and two-dimensional NMR, HRESIMS, and HRESIMS/MS data. Compounds 1 and 2 have a Δ 22 -21-sulfoxy-24-norcholestane side chain. Compounds 3 and 4 contain a Δ 24(28) -22-sulfoxy-24-methylcholestane side chain, which was first discovered in the polar steroids of starfish and brittle stars. The influence of substances 1 - 4 on cell viability, colony formation, and growth of human breast cancer T-47D, MCF-7, and MDA-MB-231 cells was investigated. It was shown that compounds 1 and 2 possess significant colony-inhibiting activity against T-47D cells, while compounds 3 and 4 were more effective against MDA-MB-231 cells.