Effect of solvents on aniseed aerial plant extraction using soxhlet and ultrasound methods, regarding antimicrobial activity and total phenolic content

Pimpinella anisum, commonly known as aniseed or anise, is a flowering plant whose fruits, characterized by distinct aroma and flavor, are widely used in Mediterranean gastronomy. This study aimed to evaluate the effect of the extraction method and solvent on the antimicrobial properties of aniseed extracts. For this purpose, hexane, diethyl ether, ethanol and aqueous extracts of aniseed aerial parts were obtained through Soxhlet and Ultrasound-Assisted Extraction (UAE) methods. The extraction yield was calculated and the antimicrobial activity against food spoilage non-pathogenic microorganisms was measured through Disc Diffusion Assay (Kirby Bauer Test). The study indicated that the Soxhlet extraction method results in higher yield and lower total phenolic content than Ultrasound-Assisted Extraction. All the extracts exhibited antimicrobial activity against certain strains, however, the activity of UAE samples were more significant. In contrast, the ethanolic extract delivered by UAE was the only one that inhibited the growth of all the tested microorganisms (bacteria, yeast and fungi). The analysis of phytochemicals revealed that ethanolic extracts contained petroselinic acid. Finally, regarding the antioxidant activity, water extract with UAE presented the strongest, that was similar with that of ascorbic acid. The observed effects provided a good starting point for further studies on Pimpinella anisum extracts for future applications in the food industry.