Use of pressurized liquid extraction technique to obtain extracts with biological and antioxidant activity from Mentha pulegium, Equisetum giganteum and Sida cordifolia

Bioactive compounds from plant extracts can be sensitive to extraction conditions, especially at high temperatures, so extraction techniques that use milder processing conditions are intensively studied and applied. Among these techniques, extraction with pressurized liquids (PLE) stands out as an efficient method widely used to obtain biocompounds of interest. In this work, the objective was to prepare extracts of M. pulegium , E. giganteum and S . cordifolia using pressurized liquids, water, ethanol and hydroethanolic solution and to evaluate yield, phenols and flavonoids content, antioxidant activity by radical scavenging method and antimicrobial capacity of the extracts, as well as modeling the kinetic extraction curves, using the Weibull and power law models. Hydroethanolic and aqueous extracts of M. pulegium showed the best yield, 40.89 and 35.09%, respectively. Weibull model was fitted to experimental kinetic curves of extraction. Hydroethanolic extract of M. pulegium showed the highest amount of phenolic compounds (323.46 mgGA/g). However, for flavonoids it was ethanolic extract of E. giganteum (291.14 mgQE/g). Antioxidant activity was better for ethanolic extract of M. pulegium (0.02 mg/mL). As for minimum inhibitory concentration, the lowest concentration was found for ethanolic extract of M. pulegium , with a value of 0.63 mg/mL, for the bacteria tested.