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Supercritical carbon dioxide extraction of chamomile flowers: extraction efficiency, stability, and in‐line inclusion of chamomile–carbon dioxide extract in β ‐cyclodextrin
Author(s) -
Kaiser C. S.,
Römpp H.,
Schmidt P. C.
Publication year - 2004
Publication title -
phytochemical analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 72
eISSN - 1099-1565
pISSN - 0958-0344
DOI - 10.1002/pca.775
Subject(s) - chemistry , supercritical carbon dioxide , carbon dioxide , extraction (chemistry) , chromatography , methanol , supercritical fluid extraction , solvent , nuclear chemistry , organic chemistry
The extraction of chamomile owers using supercritical carbon dioxide was investigated with respect to extraction efciency 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°C. A slight decrease (80–90% recovery) occurred at +5°C, whereas complete decomposition of matricine took place within 3–4 months at room temperature and at +30°C, respectively. An in‐line inclusion of chamomile constituents in β ‐cyclodextrin ( β ‐CD) during the extraction process was assessed and inclusion rates between 40 and 95% were obtained depending on the amount of β ‐CD and the type of chamomile constituent. No further stabilization of matricine in the carbon dioxide extract/ β ‐CD complexes was achieved. High residual water contents in the complexes even after freeze‐drying were identied as accelerating the decomposition. In addition, the extractability of avonoids, 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 modied carbon dioxide (18%, w/w) at 60°C and 380 bar. Extraction conditions in the two‐phase region of the binary mixture carbon dioxide–methanol (70°C, 100 bar) led to a drastic change in uid polarity and hence extractability increased to 92–95%. Copyright © 2004 John Wiley & Sons, Ltd.