Characterization and Antimicrobial Activity of Spice Extract-Loaded Algal Microcomposites Based on the Microemulsion Technique

In recent years, with the increase in knowledge and awareness, people's efforts to return to nature have increased in the field of medical science and cosmetics industry. Spices, sumac and coriander, grown and frequently used in Turkey, have different bioactive effects. Microalgae are preferred in the treatment of skin problems. The aim of this study was to synthesize algae microcomposites that were effective against bacterial infections, prepared based on microemulsion technique and loaded with spice extract. Microemulsion formulations were prepared by the titration method. Aqueous and ethanolic extractions of sumac/coriander were carried out using the ultrasonic-assisted extraction method. Twenty-four different algal microcomposites loaded with extracts were synthesized. The disk diffusion method was used to determine the antimicrobial activity. The DPPH free radical scavenging activities, the total phenolic content (TPSC), and the characteristics (FT-IR) of the microcomposites were investigated. In addition, the chemical contents of extracts were determined by the GC/MS method. Aqueous extracts of both sumac and coriander were highly effective against Escherichia coli (ES DII). The highest antimicrobial activity against Staphylococcus aureus (F6 III) was obtained with M9 (microcomposite containing ethanolic extract of sumac) and M15 (microcomposite containing aqueous extract of coriander). The highest TPSC value (6.025 mg GAE/gr) was detected in the aqueous extract of coriander. The DPPH radical scavenging activities of coriander extracts were lower than those of sumac extracts. It has been determined that the spices contain organic (propanoic, butanoic, malic and benzoic) acids and fatty (palmitic, oleic and myristic) acids. According to the results of FT-IR spectroscopy, microcomposites prepared with sumac and coriander extracts were successfully synthesized. The synthesized algae-based microcomposites have properties that could be in the green-labeled bio-based category.