Isolation and structural characterisation of five new and 14 known metabolites from the commercial starfish Archaster typicus

From the commercially available starfish Archaster typicus, five new (1–5) and 14 known (6–19) metabolites were isolated and identified. Detailed 1D and 2D NMR spectroscopic data, including 1H, 13C, DEPT, HSQC, HMBC, and NOESY, established the structures of the new metabolites as sodium 5α-cholesta-9(11),24-dien-3β,6α,20β-triol-23-one 3-sulphate (1), sodium 5α-cholesta-9(11)-en-3β,6α,20β-triol-23-one 3-sulphate (2), sodium (25R)-5α-cholestane-3β,4β,6α,8,14α,15β,26-heptaol-15-sulphate (3), sodium (25R)-5α-cholestane-3β,6α,8,14α,15β,26-hexaol 15-sulphate (4), and sodium cholest-25(27)-ene-3β,4β,5α,6α,7β,8β,14α,15α,24,26-decanol 6-sulphate (5). Other spectroscopic techniques, including IR, ESI–MS, and HR-ESI–MS, were also adopted to further confirm the structures of the metabolites. These five steroids (1–5) are reported in nature for the first time. All of the steroids found in A. typicus (1–12) were tested for anticancer activities against MDA-MB-435 and Colo205 tumour cells. However, only sodium 5α-cholesta-9(11)-en-3β,6α,20β-triol-23-one 3-sulphate (2) and 27-nor-5α-cholestane-3β,4β,5,6α,7β,8,14,15α,24α-nonaol (6) exhibited weak activities.