Cytotoxic Synergism and Target Prediction of Chemical Constituents from the South China Sea Sponge Pseudoceratina sp.

Based on the screening of tumor cytotoxicity, fractions and compounds from the South China Sea sponge Pseudoceratina sp. were isolated and purified by silica gel column and HPLC. The structures were identified by ESI-MS and NMR spectroscopy. The anti-proliferation of fractions and compounds against A549, HepG2 and HeLa cell lines had been investigated by SRB method. The targets in the cell were calculated and predicted by Chemmapper Server. The results showed that two bromotyrosine alkaloids were obtained and identified as hemifistularin-3(1) and 11, 19-dideoxyfistularin 3(2). Their IC₅₀ values were higher than 91.76 μmol/L against three tumor cells. While the combination of the two compounds at a certain ratio showed good cytotoxicity, the IC₅₀ value against A549 cells was as low as 8.71 μmol/L, which indicated that the two compounds had significant synergistic effect on three tested tumor cells. Their targets might focus on Hsf1 protein and Vanilloid Receptor 1 and the synergistic effect might be associated with multi-target of compounds. [ABSTRACT FROM AUTHOR]