Biologically active lignans from caulomas (stems) and leaves of Schisandra chinensis were extracted with supercritical carbon dioxide at the pressures 20–27MPa, temperatures 40, 50 and 60°C, and solvent-to-feed ratio 36–43. Six major lignans were determined by means of HPLC: schizandrin, gomisin A, deoxyschizandrin, γ-schizandrin, gomisin N and wuweizisu C. At the optimum conditions 27MPa and 50°C, the extraction yield of lignans from caulomas was 1.3% dry weight and their content in the extract was higher than 32wt.%. At the optimum conditions for CO2 extraction from S. chinensis leaves, 27MPa and 60°C, the yield of lignans was 0.22% d.w. and the yield of (E)-cinnamic acid was 0.18% d.w. Addition of 2–4% ethanol to CO2 increased the extraction rate but not the final yield of lignans. The solubility of extracted substances in supercritical CO2 was estimated from their extraction rates.

β-Sitosterol (22,23-dihydrostigmasterol) and scopoletin (7-hydroxy-6-methoxycoumarin) were extracted from roots of stinging nettle (Urtica dioica L.) with supercritical and liquid CO2. Extraction rates were measured for both oleoresin and the individual substances in dependence on extraction conditions. The solvent modified with ethanol (0–9.4wt.%) was applied at the pressures of 100, 200, 250 and 280bar and the temperatures of 25, 40 and 60°C. Extracts were analysed by means of HPLC method. The maximum yields of β-sitosterol and scopoletin were 0.63 and 0.058mg/g dry mass, respectively. In comparison with the extract obtained with diethyl ether, the maximum yields obtained with CO2 were at least two times higher for both investigated substances. A model describing the extraction of a solute that is present in two forms, free and interacting with matrix, was applied to interpret the experimental extraction curves.

The drug Wuweizi (dried fruits of Schisandra chinensis or S. sphenantherd) is one of important medicinal means used in the Oriental medicine. The lignans of dibenzo[a,c]cyklooctadiene type are major constituents, a volatile oil with mono- and ses-quiterpens, an oil, organic acids and small amounts of additional compounds are also present. The content of major lignans (schizandrin, deoxyschizandrin, gomisin A, gomisin N, γ-schizandrin, wuweizisu C) in commercially available drugs ranges usually between 3 and 5%. The present paper biefly comments the isolation and biological activity of the lignans and is especially concerned with analytical methods (TLC and HPLC) for the determination of the drug fingerprint and methods for the determination of constituents in drugs, mixtures and biological materials. HPLC methods using RP-silica bonded phases and diluted methanol, acetonitrile (or a mixture of both), are most important for these purposes. Electromigration methods are less suitable and the importance of hyphenation procedures is practically negligible.

Chlorophylls and carotenoids were extracted from leaves of stinging nettle (Urtica dioica L.) with supercritical and liquid CO2. The solvent modified with ethanol (0–7wt.%) was applied at the pressures of 200, 250 and 280bar and the temperatures of 25, 40 and 60°C. Extracts were analysed by means of HPLC and RP-HPLC methods. The maximum yields of chlorophyll a, chlorophyll b, β-carotene and lutein obtained with CO2 were 73, 100, 24 and 39mg/100g dry matter, respectively. In comparison with the extract obtained using conventional solvents, the maximum yields obtained with CO2 were similar for carotenoids, higher for chlorophyll b and lower for chlorophyll a. Chlorophyll a partially degraded in the extractor to the more soluble pheophytin a; the extent of carotenoid degradation was much lower than that of chlorophylls. The degradation was substantially reduced by addition of a small amount of antioxidant to the solvent. Extraction rates in dependence on extraction conditions were measured both for individual pigments and for oleoresin. A model describing the extraction of a solute that is present in two forms, free and interacting with matrix, was applied to interpret the experimental extraction curves. A loss of volatile substances from the ground nettle leaves and a decrease in β-carotene content from 24 to 18mg/100g dry matter was observed during the period of 155 days between the first and last experimental run.

Six major lignans (schizandrin, gomisin A, deoxyschizandrin, γ-schizandrin, gomisin N, wuweizisu C) in the caulomas and leaves of Schizandra chinensis (Turcz.) Baill., and cinnamic acid in the leaves of the plant, were quantitatively analysed by high-performance liquid chromatography in reversed-phase mode with UV detection. Resolution of the determined lignans was evaluated for two multistep gradients applied. Samples for HPLC analysis were prepared by extraction with supercritical carbon dioxide at pressures of 20–27 MPa and temperatures of 40–60°C. Kinetics of the extraction of individual components was measured and simulated with a model.

Oil from the seed and pulp of sea buckthorn berries (Hippophaë rhamnoides L.) was extracted with carbon dioxide at pressures 9.6–27 MPa and temperatures 25–60°C. Influence of extraction conditions on solubility and mass transfer rate was studied. No marked changes in composition of extracted oil in the course of extraction were observed. Experimental extraction curves were evaluated using a model with grinding efficiency, volume mass transfer coefficients in solid and fluid phases, and parameter of flow asymmetry as adjustable parameters. The solid-phase mass transfer coefficient was increasing with rising temperature.

Oleoresin was extracted from ground black pepper with carbon dioxide at 28 MPa and 24 to 60 degrees C. The yield and contents of piperine in the extract were determined as a function of extraction time and the solvent amount. The concentration profile of piperine inside the fixed bed of pepper was also measured. The total extract contained piperine and essential oil in the proper ratio to be used directly in food industry.The experimental results showed a strong variation of extract composition during the extraction. They were simulated using the extended Lack's model with mass transfer coefficients in the solvent and solid phase and with grinding efficiency as parameters. The parameters were determined individually for each of the three extract components, representing essential oil, piperine, and other nonpolar substances.