Supercritical carbon dioxide extraction of chamomile flowers: extraction efficiency, stability, and in-line inclusion of chamomile-carbon dioxide extract in beta-cyclodextrin.
The extraction of chamomile flowers using supercritical carbon dioxide was investigated with respect to extraction efficiency and compared with solvent extraction. The stability of matricine, a sensitive constituent of the essential oil of chamomile, in these extracts was studied during storage at different temperatures over 6 months. Matricine was stable at -30 degrees C. A slight decrease (80-90% recovery) occurred at +5 degrees C, whereas complete decomposition of matricine took place within 3-4 months at room temperature and at +30 degrees C, respectively. An in-line inclusion of chamomile constituents in beta-cyclodextrin (beta-CD) during the extraction process was assessed and inclusion rates between 40 and 95% were obtained depending on the amount of beta-CD and the type of chamomile constituent. No further stabilization of matricine in the carbon dioxide extract/beta-CD complexes was achieved. High residual water contents in the complexes even after freeze-drying were identified as accelerating the decomposition. In addition, the extractability of flavonoids, such as apigenin and apigenin-7-glucoside, was determined. Apigenin-7-glucoside, the more hydrophilic substance, was not extractable with pure carbon dioxide and showed a recovery of 11% using methanol modified carbon dioxide (18%, w/w) at 60 degrees C and 380 bar. Extraction conditions in the two-phase region of the binary mixture carbon dioxide-methanol (70 degrees C, 100 bar) led to a drastic change in fluid polarity and hence extractability increased to 92-95%.
Department of Pharmaceutical Technology. Auf der Morgenstelle 8. D-72076 Tübingen, Germany.
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Kaiser
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Römpp
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Schmidt
D000893:Anti-Inflammatory Agents / Q000737:chemistry / Q000302:isolation & purification; D047310:Apigenin; D002245:Carbon Dioxide / Q000737:chemistry; D020843:Chamomile / Q000737:chemistry*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D003505:Cyclodextrins / Q000737:chemistry*; D005419:Flavonoids / Q000302:isolation & purification; D035264:Flowers / Q000737:chemistry; D007783:Lactones / Q000737:chemistry / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification*; D045789:Sesquiterpenes, Guaiane; D047392:beta-Cyclodextrins
D000893:Anti-Inflammatory Agents; D003505:Cyclodextrins; D005419:Flavonoids; D007783:Lactones; D010936:Plant Extracts; D012717:Sesquiterpenes; D045789:Sesquiterpenes, Guaiane; D047392:beta-Cyclodextrins; D002245:Carbon Dioxide; C057792:apigetrin; D047310:Apigenin; C031215:betadex; C039959:matricin