Disulfated Ophiuroid Type Steroids from the Far Eastern Starfish and Their Cytotoxic Activity on the Models of 2D and 3D Cultures.

New steroidal 3β,21-disulfates (-), steroidal 3β,22-disulfate (), and the previously known related steroidal 3β,21-disulfate () were isolated from the ethanolic extract of the Far Eastern starfish , collected off Urup Island in the Sea of Okhotsk. The structures of these compounds were determined by intensive NMR and HRESIMS techniques as well as by chemical transformations. Steroids and have an oxo-group in the tetracyclic nucleus at position C-7 and differ from each other by the presence of the 5(6)-double bond. The Δ-22-sulfoxycholestane side chain of the steroid has not been found previously in the starfish or ophiuroid steroids. The cytotoxic activities of , , , and the mixture of and were determined on the models of 2D and 3D cultures of human epithelial kidney cells (HEK293), melanoma cells (SK-MEL-28), small intestine carcinoma cells (HuTu80), and breast carcinoma cells (ZR-75-1). The mixture of and revealed a significant inhibitory effect on the cell viability of human breast carcinoma ZR-75-1 cells, but other tested compounds were less effective.