Evaluation of the effects of diethyl ether and methanol extracts of carpet anemone (Sarcophyton spp.) and starfish (Pentaceraster spp.) on E. coli and Bacillus subtilis bacteria

Marine environment is the main source of natural bioactive products whose chemical-structural properties are not similar with other natural products of plants and other inland organisms. The present study was carried out to evaluate antibiotic properties of diethyl ether and methanol extracts of two marine species including starfish and carpet anemone. The samples of starfish and carpet anemone were collected from the Lark Island coasts. Extraction was done using diethyl ether and methanol solvents and antibiotic properties analysis on Escherichia coli and Bacillus subtilis were evaluated using agar diffusion method. Then tube dilution to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). According to the results, diethyl ether extract from carpet anemone had no inhibitory effect on E. coli bacteria. While, starfish methanol extract (40 mg/ml) showed a growth inhibitory effect on E. coli bacteria. The starfish methanol extract (30 and 50 mg/ml) had a growth inhibitory effect on B. subtilis bacteria. Carpet anemone methanol extract (40 mg/ml) cause a growth inhibitory effect on E. coli, but did not have a deleterious effect. Starfish methanol extract showed the highest growth inhibitory effect on B. subtilis and created a growth inhibitory circle zoon (12.1±0.8 mm diameter). The results showed that the methanolic extract of the starfish has higher growth inhibitory effect on the two studied bacterial species. In conclusion, methanolic extracts of the starfish were effective in inhibiting the growth of Bacillus subtilis bacteria and methanolic extract of carpet anemone in inhibiting E. coli bacteria growth.