Kinetics of Extraction of Biologically Active Substances from Medicinal Plant Raw Materials using Different Techniques

Resumo

The problems and peculiarities of obtaining the kinetic characteristics of extraction of biologically active substances (BAS) from a plant matrix are discussed. The establishment of kinetic characteristics of the extraction of BAS under various extraction conditions is studied on the example of samples of Hypericum perforatum and Salvia officinalis. The lowest value of the average rate constant of the extraction of BAS from the materials examined is characteristic of a variant of static extraction with an aqueous alcohol extractant under heating. The methods of static extraction under heating (according to the requirements of pharmacopoeia articles) and ultrasonication, as well as using double ultrasonication differ little from each other in their kinetic efficiency. The method of dynamic extraction of BAS at an elevated temperature and pressure is characterized by the highest values of the rate constant, which leads to an acceleration of the diffusion of the BAS into the extractant’s medium. It is noted that the extraction processes and chemical transformations of some BAS (hyperforin, carnosic acid, etc.) occur simultaneously as confirmed by the decrease in their concentrations in the extractant during the extraction from plant samples.