Antibacterial activity of Oscillatoria ethanolic extract and extracted phenolic compounds

The aim of this study is to investigate the antibacterial effect of cyanobacterium via detection of phenolic compounds with antibacterial activity, Recently, a new search for friendly to the environment alternatives to antibiotics has been explored, so there is a trend to use cyanobacteria, which are one of type of microalgae as a source for obtaining compounds that have an anti-bacterial effect. Cyanobacteria is an important source of many bioactive compounds, such as phenols, alkaloids, terpenes, fatty acids, and many other bioactive compounds. Ethanolic extract of Oscillatoria had no effect towards Gram positive Staphylococcus aureus, Bacillus subtilis) and negative bacteria (Pseudomonas aeruginosa, Escherichia coli), while the phenolic compound isolated from that ethanolic extract showed a clear effect on the above-mentioned bacteria. The Gram-positive bacteria are more sensitive to phenols compared with a negative one, according to the results of inhibition zones diameters for each treatment. The highest inhibition (20, 19 mm) for Gram positive bacteria and (10, 16 mm) for Gram negative. Many phenols have been diagnosed through the use of HPLC technology such as Quercetin (11.8%), Apigenin (11.5%), Rutin (44.4%), Kaempferol (5.2%) and Luteolin (9.4%).