Cytotoxic effects on tumour cell lines of fatty acids from the marine sponge S copalina ruetzleri

Objectives Marine sponges are among the most promising sources of chemically diversified fatty acids (FAs). In addition, several studies have shown the effect of polyunsaturated FAs on cancer therapy. This research carried out a biological and chemical evaluation of the sponge Scopalina ruetzleri collected on the South Brazilian coastline. Methods Bioassay-guided fractionation of S. ruetzleri was performed in human glioma (U87) and neuroblastoma (SH-SY5Y) cell lines, and the in-vitro effects on free radicals were evaluated. Key findings The ethyl acetate fraction of S. ruetzleri showed promising cytotoxic effects in cancer cell lines, with IC50 < 20 μg/ml. Fingerprint 1H Nuclear Magnetic Resonance (NMR) analysis showed that this fraction is mainly constituted of FAs. Through FA methyl ester analysis, it was possible to identify 32 FAs. In addition, some minor unusual FAs for the marine biosphere were identified. The results of conjugated dienes method showed that FAs fraction, at concentrations above 50 μg/ml, has a pro-oxidant effect, indicating that lipid peroxidation may be partially responsible for the mechanism of cytotoxicity on cancer cells. Conclusion This work also contributes to studies that focus on the application of FAs on cancer therapy as a new adjuvant to radio or chemotherapy, or as a chemotherapeutic agent.