Application of ultrasound-assisted extraction to obtain antioxidant compounds from leaves of Echinodorus macrophyllus

The objective of this study was to evaluate the effectiveness of ultrasound-assisted extraction (UAE) in obtaining the extract from the leaves of Echinodorus macrophyllus using ethanol as a solvent. The influence of temperature, ultrasound power, and sample/solvent ratio on extraction yield were analyzed, as well as squalene content, phenolic compound content, antioxidant activity, and antimicrobial activity. A higher extraction yield (10.93 wt%) was obtained at 40 °C, amplitude percentage of 70% (525 W), and a solvent/sample ratio of 30 mL g−1. The extract obtained at 40 °C, ultrasound power at 525 W and solvent/sample ratio of 10 mL g−1, presenting 52.95 mg gallic acid equivalent (GAE) 100 g−1 of extract and concentration of 0.56 mg mL−1 required to inhibit the DPPH• radical by 50%. All extracts contained the chemical compound squalene in their composition, with the highest recorded concentration being 0.3795 g squalene 100 g−1 of extract. Antimicrobial analysis revealed that the extracts showed weak potential against strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. [Display omitted] •Higher extraction yield (10.93 wt%) was obtained at 40 °C, amplitude percentage of 70% and a solvent/sample ratio of 30 mL g−1.•Squalene was detected in the chemical composition of all extracts and the highest concentrations was 0.3795 g squalene 100 g−1 of extract.•The lowest temperature tested indicated obtaining higher levels of phenolic compounds and higher antioxidant activity.•Extracts showed weak potential against strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa.