CYTOTOXIC AND ANTICANCER AGENTS IN MUCUS OF GALAXEA-FASCICULARIS - PURIFICATION AND CHARACTERIZATION

Various cytotoxic components derived from the mucus of the coral Galax ea fascicularis were investigated. Chromatography of the crude mucus e xtract through CM-Sepharose separated the components into 15 peaks, ni ne of which were found to express cytotoxic activity against rat liver cells. Trypan blue dye exclusion assay indicated that peaks P4, P5, a nd P8b induced the highest level of cytopathy in normal rat liver cell s. P4 and P5 contained both proteinaceous and nonproteinaceous compone nts and had heat-labile protease activity. The cytotoxins in P4 and P5 were nonproteinaceous. Further purification of P8b using a normal-pha se silica column on HPLC yielded a nonproteinaceous and sugar-rich cyt otoxin, S2. Mass spectrometry indicated S2 to be 742 Da in size. On in cubation with endo-beta-galactosidase, S2 lost more than 50% of its ac tivity, suggesting that its active moiety is glycosylated. Further ana lysis of the carbohydrate composition revealed that S2 contained an N- linked sialylate glycan chain of NeuNAc alpha(2-6)Gal beta(1-4)GlcNAc. Of the cancer cell lines tested with the mucus components, a vincrist ine-resistant murine leukemia cell (P388/VCR) was found to be most sus ceptible, with an LD50 of 0.3 mu g/ml, thereby suggesting the potentia l of this coral mucus as a source of important compounds for anticance r drug screening and development.