Intensification of the Extraction Yield of Eucalyptus globulus Phenolic Compounds with Pulsed Electric Field

Abstract

Eucalyptus extract-based pharmaceutical products are widely used because of their medicinal properties and their rich content of secondary metabolites, mainly phenolic compounds. This study aimed to maximise the extraction yield of these compounds and reduce the extraction duration by using a pulsed electric field (PEF) level of 6 kV/cm. The pulse width (T), number of pulses (n), and solvent concentration [C] were analysed. Several ethanolic extracts were obtained from the leaves of Eucalyptus globulus, and the content of total phenols, total flavonoids, and condensed tannins was measured through spectrophotometry. The results, obtained immediately after PEF treatment, revealed that for optimal values of the analysed factors, the total phenol content doubled and the flavonoid content increased significantly. However, PEF pre-treatment had no effect on the tannin yield. Moreover, optimisation was performed using the design of experiments methodology for identifying optimal values of the analysed factors.