Antibacterial and hemolytic effects of aqueous and organic extracts from different tissues of sea urchin Echinometra mathaei on pathogenic streptococci

Abstract

In this study, the antibacterial and hemolytic effects of the gonadal tissue, test, spines and Aristotle's lantern of the sea urchin (<em>Echinometra mathaei</em>) were investigated. The aerobic Gram-positive pathogenic bacteria <em>Streptococcus mutans</em> and <em>Streptococcus sobrinus</em> were selected because of their importance in oral diseases. The samples of sea urchin were collected from an intertidal zone in the Persian Gulf and then dissected. Finally, the crude extracts of the gonadal tissue, test, spines and Aristotle's lantern of the samples were separately prepared by the solvents, including phosphate-buffered saline (PBS), 96 % ethanol (Et) and 80 % acetonitrile (ACN). The antibacterial activities of the extracts were evaluated using the well diffusion method in two concentrations of 1500 and 600 µg well−1. The antibacterial effects against streptococcal species were observed in the organic extracts (Et and ACN) of the gonads and test while the extracts of spines and Aristotle's lantern showed no antibacterial activity. The hemolytic activity of the PBS, 96 % Et, and 80 % ACN extracts from the sea urchin were evaluated using horse red blood cells. Hemolytic activity was observed only in the 80 % Et and ACN extracts of the gonad and test. In conclusion, the organic extracts of gonadal tissue showed the most inhibitory activity on the growth of <em>S. mutans and S. sobrinus.</em>