Marine organisms are prolific sources of novel biologically active organic molecules with diverse structures. The antimicrobial and in vitro cytotoxic activity of methanolic extracts of Holothuria cinerascens and Stomopneustes variolaris were examined. The antimicrobial activity against various pathogens such as Aeromonas hydrophila, Edwardsiella tarda, Enterobacter ludwigii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Vibrio cholerae, and V. parahaemolyticus was also evaluated. The in vitro cytotoxicity was tested in Ehrlich Ascites Carcinoma cells. Results of the study highlighted that the methanolic extract of S. variolaris had high antimicrobial and cytotoxic activities compared to that of H. cinerascens. E. coli and K. pneumoniae were highly sensitive to these extracts

Cytotoxicity, antibacterial activity, trypan blue dye exclusion assay, broth microdilution assay, Holothuria cinerascens, Stomopneustes variolaris