Cytotoxic and antibacterial activities of Holothuria (Mertenssiothuria) leucospilota extracts

There are several studies on biological activities of echinoderms’ secondary metabolites. Sea cucumbers are known to contain natural products with biological activities. Different sea cucumber species exist in Iranian waters of Oman Sea. We investigated cytotoxic and anti- bacterial activities of Holothuria (Mertensiothuria) leucospilota form Chabahar Bay. We derived four methanolic, chloroformic, n-hexane and aqueous extracts of sea cucumber, H. (Mertensiothuria) leucospilota. The cytotoxic activity of these extracts were evaluated by MTT and brine shrimp lethality assays. Disc diffusion method was used to evaluate antibacterial effect of H. (Mertensiothuria) leucospilota extracts against two gram negative pathogenic bacteria: Escherichia coli (PTCC 1399) and E. coli K 12 (ATCC 23716), and two gram positive pathogenic bacteria: Staphylococcus aureus (ATCC 25923) and Listeria monocytogenes (ATCC 19117). Methanolic extract (100 mg/mL) was effective on S. aureus and L. monocytogenes while aqueous extract of H. (Mertensiothuria) leucospilota (100 mg/mL) demonstrated antibacterial effect against all tested strain. Chloroformic extract (100 mg/mL) was effective on both E. coli K 12 and S. aureus, while n-hexane extract (100 mg/mL) was just effective on E. coli. Studying brine shrimp lethality assay indicated that all experimented extracts had strong cytotoxic activity with LC50 = 1.2–2.3 µg/mL. MEHL, ChEHL and n-hEHL showed cytotoxic effect on Caco-2 with 0/6, 0/8 and 1 mg/mL LC50, respectively. Due to our results, it can be said that Holothuria (Mertensiothuria) leucospilota extracts are potential antibacterial and cytotoxic agents.