Antibacterial activity of phlorotannin extract of brown algae Sargassum tenerrimum and its enriched cream against acne-related bacteria

Consideration of marine organisms as potential sources of bioactive compounds and drug agents has increased in recent years. Skin is considered to be the largest and fastest growing organ in the human body and it plays the most important role in protecting of diseases and environmental factors. Due to the large surface area of the skin, it is sensitive to various diseases, including acne, dermatitis, and so on. Therefore, the present study was performed to evaluate the effect of brown algae phlorotannin extract and emulsion containing the extract against 6 pathogenic bacteria. Phlorotannin content was measured using phluoroglucinol reagent. Then, the antibacterial activity of the extract and its emulsion against 6 bacterial strains including Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Propionibacterium acnes and Staphylococcus epidermidis were evaluated. The phlorotannin content was 13.94±0.29. The results showed MIC and MBC levels were lower in S. aureus, P. aeruginosa and P. acnes than in E. coli, B. subtilis and S. epidermidis, indicating the better performance of phlorotannin extract against them. Also, the emulsion containing the extract had a diameter of inhibition zone against P. acnes, E. coli, P. aeruginosa, B. subtilis. The results show that the formulation containing phlorotannin extract has potentials in the treatment of bacterial skin infections.