Bioactivity of extracts from gonadal tissue of the edible Australian purple sea urchin Heliocidaris erythrogramma

Dichloromethane (DCM), methanol (MeOH) and aqueous extracts of male gonadal tissue from Heliocidaris erythrogramma were screened for bioactivity. None of the extracts were antibacterial against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The aqueous extract scavenged the reactive oxygen species (ROS), hydrogen peroxide (H2O2), but did not react with the hydroxyl radical (OH center dot) or with the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH center dot). No antioxidant potential was evident for the DCM and MeOH extracts. The extracts displayed various levels of anti-inflammatory action in connection with inhibition of cyclooxygenase (ovine COX-1 and COX-2), but were insignificant inhibitors of lipoxygenase (soybean 15-LO) pure enzyme. Anti-inflammatory action related to reduction of leukotriene production by stimulated porcine neutrophils was affected only by the aqueous extract. The DCM and aqueous extracts, but not the MeOH extract, showed anti-inflammatory activity in rats developing adjuvant-induced polyarthritis. Overall, the DCM extract was 75% inhibitory of arthritis symptoms, and the aqueous extract was 55% inhibitory. Suppression of growth of the mouse leukaemic lymphoblastic (P388) cell line was evident for the DCM extract only. This extract was also able to exert a cytotoxic effect on the tumour cell line. For all extracts, no general cytotoxicity against isolated rat hepatocytes was observed