pH-dependent cytotoxic effects of extracts of the marine sponge Polymastia janeirensis on cancer cell lines

Abstract

The purpose of this work was to study the cytotoxic effects of marine sponge Polymastia janeirensis, which has been observed in the field to release an orange substance that is toxic to fish. The result showed that aqueous extract (pH 7.0) was highly cytotoxic to glioma (U87) and neuroblastoma (SHSY5Y) cancer cell lines (IC₅₀ < 1.0 μg/mL). In addition, this extract showed potent antioxidant and procoagulant (decreased the clotting time by 1.7-fold) activities. Interestingly, the cytotoxic effects were pH-dependent since the viability of the cancer cells was not affected with the extract (pH 5.5). The close similarity between the aqueous extract (pH 7.0) and the orange liquid that is released by the sponge indicates that this potential chemical defence of P. janeirensis deserves further investigation.

Keywords:

• Polymastia janeirensis
• chemical defence
• cytotoxic
• pH-dependent activity

Acknowledgements

We are grateful to CNPq and FAPERGS for their financial support and Hospital de Clínicas de Porto Alegre (HCPA) for providing the plasma samples.