ABSTRACT
To obtain water-soluble holothurian glycosides with high tumor suppressing activities from Apostichopus japonicus, macroporous resin, silica gel and gel-filtration column chromatograghy were used to purify the water-soluble holothurian glycosides, and their tumor suppressing activity and inducing apoptosis of tumor cells were examined in this study. The 70% ethanol fraction of macroporous resin column, the pSC-2 and pSC-3 fractions from silica gel column showed very strong tumor suppressing activity towards HeLa cells, A-549 lung cancer cells, SGC-7901 stomach cancer cells and Bel-7402 liver cancer cells. SC-2 and SC-3 fraction purified from Sephadex LH-20 gel-filtration column chromatography, with a purity above 99.6%, all had the properties of triterpenoid glycosides. Purified SC-2 fraction had remarkable tumor suppressing activity on HeLa cells in a dose- and time-dependent manner, and had prominent tumor suppressing activity to mouse S180 solid tumors in a dose-dependent manner. Besides, the SC-2 fraction also had remarkable ability in elevating mouse thymus index and spleen index. The purified SC-2 fraction could induce apoptosis of HeLa cells in a dose-dependent manner, and DNA fragmentation of HeLa cells occurred after treated 12 h with 10 mg x L(-1) and 50 mg x L(-1) of SC-2 fractions. From the results, it can be concluded that the purified SC-2 fraction of water-soluble holothurian glycosides has extremely strong tumor suppressing activity, and the suppression is realized by inducing tumor cells to undergo apoptosis. This study lays solid foundation for development of highly effective new natural anticancer agents from sea cucumbers.