EXTRACTION OF HERBAL DRUGS: COMPRATIVE EXTRACTION OF CIRCULAR AND EXTRACTION WITH SUPERCRITICAL CARBON DIOXIDE

The most commonly used methods of isolation and concentration of certain constituents from herbal drugs with selected solvents are maceration, doubled maceration, digestion, turboextraction, percolation, repercolation, ultrasonic-assisted extraction and counter-current extraction. According to their consistency, extracts can be classified as liquid, soft and dry extracts. Circular extraction is the process in which the solvent at the increased temperature continuously circulates through the column of plant material. Extraction by supercritical fluids (SFE), which uses compressed fluids heated over their critical temperatures, in last years, is becoming more and more the part of the common practice. In this article comparative analysis of extracts of thyme obtained by circular and SFE extraction with carbon dioxide was carried out. Analysis was focused to determination yields of total extracts and the content of thymol in the samples obtained by two different extraction techniques. The yield of the extract obtained by SFE was lower in comparison to that obtained by circular extraction. Simultaneously, content of thymol in the SFE extract was significantly higher