Supercritical carbon dioxide extraction of selected medicinal plants—effects of high pressure and added ethanol on yield of extracted substances

Abstract

The possibilities and limitations of supercritical fluid extraction of natural products of low, medium and high polarity under very high pressure and with polar modifiers has been investigated. The medicinal herbs marigold (Calendula officinalis), hawthorn (Crataegus sp.) and chamomile (Matricaria recutita) were used as models in this study. Extraction profiles and the spectra of extractable metabolites were recorded following extraction with mixtures of carbon dioxide:ethanol of varying proportions (0-20% ethanol) and at various pressures in the range 300-689 bar. Components were identified by HPLC-PAD-MS or GC-MS and quantified by HPLC or GC as appropriate. Extraction yields under the varying conditions depended to a large extent on the profiles of secondary metabolites present in the three drugs. Whereas the extractability of lipophilic compounds increased substantially at pressures above 300 bar, the yields of polyphenolic and glycosidic compounds remained low even at 689 bar and with 20% modifier in the extraction fluid.

Extraction of Apigenin and Luteolin from Leaves of Alfalfa (<i>Medicago sativa</i> L.) Using Mixtures of Liquid Carbon Dioxide and Ethanol

“…This result shows that the yields of luteolin and apigenin are insensitive to the liquid CO 2 operating pressure. The effects of operating temperature and pressure on the extraction yield are similar to the results from other liquid CO 2 extractions [7,16,19,20]. Under this extraction condition (temperature = 20 ºC, pressure = 8.5, 10, and 14 MPa), the gas phase and the liquid phase coexist in the extraction vessel.…”

Extraction of Luteolin and Apigenin from Leaves of <i>Perilla frutescens</i> (L.) Britt. with Liquid Carbon Dioxide

“…The pressure was set at 8.5, 10 and 14 MPa. The temperature was set at 20 ºC because the temperature at which unstable phases of gas and liquid exist near the critical temperature of extractions [16,17]. Under this extraction condition (temperature = 20 ºC, pressure = 8.5, 10, and 14 MPa), the gas phase and the liquid phase coexist in the extraction vessel.…”

Optimization of Extraction Condition for Supercritical Carbon Dioxide (SCCO 2) Extraction of Strobhilantes crispus (Pecah Kaca) Leaves by Response Surface Methodology

“…Among all the polar co-solvents including methanol, ethanol, acetonitrile, acetone, water, ethyl ether and dichloromethane, methanol is the most commonly used because it is an effective polar co-solvent and is up to 20% miscible with CO 2 . However, ethanol may be a better choice in SFE of nutraceuticals because of its lower toxicity [3,4].…”