Investigation of antibacterial effect of red algae Gracilaria gracilis extract

Today, due to increase in resistance of antibiotics, it is necessary to find suitable alternatives to natural materials. Algae also have many applications in medicine, pharmacy and the food industry.  Therefore, the present study was performed to investigate the antibacterial activity of red algae Gracilaria gracilis extract. In this study, the active compounds of methanolic extract of red algae G. gracilis were identified by gas chromatography-mass spectrometry (GC/MS). The Antimicrobial effect of algae extract on bacteria were investigated by sequential dilution method. The chemical analysis of the algae extract compounds showed that the major components of the extract were phenylethine, silacyclopntenen, phthalic acid, n-hexadecanoic acid, dibutyl phthalate, phytol and gibberellin. In the study of minimum inhibitory concentration and minimum bactericidal concentration, it was shown that Pseudomonas aeruginosa and Staphylococcus aureus with algae extract with a minimum inhibitory concentration of 6.2 and 112.5 mg/mL, respectively, compared to other studied bacteria, showed more sensitivity. Based on the results, the methanolic extract of red algae G. gracilis had good antimicrobial activity. Therefore, clinical research is necessary for the clinical applications of this extract.