Abstract
In this study, the antibacterial and hemolytic effects of the gonadal tissue, test, spines and Aristotle’s lantern of the sea urchin (Echinometra mathaei) were investigated. The aerobic Gram-positive pathogenic bacteria Streptococcus mutans and Streptococcus sobrinus 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 S. mutans and S. sobrinus.
Highlights
Microbial populations in seawater and sediments may be as high as 106 and 109 per milliliter, respectively (Austin 1988)
Histological sections of the gonads showed that the studied samples were female gender (Fig. 4)
The results showed that antibacterial activities were found in some tissues of the echinoderm species Echinometra mathaei tested against streptococci
Summary
Microbial populations in seawater and sediments may be as high as 106 and 109 per milliliter, respectively (Austin 1988). Marine invertebrates are constantly exposed to high concentrations of bacteria, fungi and viruses, many of which may be pathogenic. The survival of these organisms depends on efficient antimicrobial mechanisms to protect themselves against microbial infections. There has been an increment in research on marine crustaceans, sponges, jellyfish, sea anemones, corals, bryozoans, molluscs, tunicates and echinoderms with particular interest on their secondary metabolites containing desirable antimicrobial properties (Bhakuni and Rawat 2005; Casas et al 2011; Haug et al 2002).
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