Rational Parameters for Ultrasonic Extraction of Bioactive Compounds from Hypericum perforatum

Abstract

A study was conducted to determine the optimal parameters for ultrasonic extraction of biologically active compounds (BAC) from St. John's wort (Hypericum perforatum L.). The selected variable factors included extractant temperature (X1), solid-to-liquid ratio (X2), and exposure time (X3). The experimental design was based on a central composite rotatable uniform design and a full factorial experiment with a total of 20 runs. The collected experimental data were processed using mathematical methods, resulting in second-order nonlinear regression models describing the dry matter yield (Y1) and antioxidant activity (Y2) of the extracts. An analysis of the regression coefficients revealed that extractant temperature had the strongest influence on both output parameters, while exposure time had the weakest. The optimal parameter ranges were identified as follows: X1 = 47–50.8 °C, X2 = 1:19.8–1:21 g/cm³, X3 = 14.7–21.6 minutes. Under these conditions, the yield of dry matter ranged from 49.362 to 50.5 g/kg and antioxidant activity from 387.89 to 410.50 mg/dm³. A direct-flow extractor design was proposed, enabling a continuous extraction process with ultrasonic treatment. The implementation of this equipment improves the efficiency of BAC extraction, reduces extraction time and solvent consumption, and preserves the biological properties of the extract. The results obtained are suitable for scaling up and can be applied in the development of industrial technologies for producing herbal medicinal products and functional food ingredients based on St. John’s wort.