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 Δ22-21-sulfoxy-24-norcholestane side chain. Compounds 3 and 4 contain a Δ24(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.

For the first time tetravalent palladium is detected, coordinated exclusively by simple oxoanions. Stabilization was achieved by formation of the [Pd(S2 O7 )3 ](2-) complex in which three chelating disulfate groups surround the metal atom. The salt K2 [Pd(S2 O7 )3 ] could only be obtained if the reaction of K2 [PdCl6 ] and neat SO3 was performed in the presence of XeF2 .