Abstract
Seven new polyoxygenated steroids belonging to a new structural group of sponge steroids, gracilosulfates A-G (1-7), possessing 3β-O-sulfonato, 5β,6β epoxy (or 5(6)-dehydro), and 4β,23-dihydroxy substitution patterns as a common structural motif, were isolated from the marine sponge Haliclona gracilis. Their structures were determined by NMR and MS methods. The compounds 1, 2, 4, 6, and 7 inhibited the expression of prostate-specific antigen (PSA) in 22Rv1 tumor cells.