Abstract
Considering that approximately a third of all drugs currently on the
market is derived from natural products, curcumin attracted attention due to
its anticancer, antioxidative, antiinflammatory and antimicrobial properties.
Unfortunately, its low solubility and depending on that a poor bioavailability
are limiting factors for its clinical application. It was shown that the
administration of curcumin with piperin, the main component of black pepper,
increased the bioavailability of curcumin. In addition, piperine increased the
plasma concentration and delayed the elimination of drugs like phenytoin and
rifampin, and has antiinflammatory and antifungal properties among others.
Considering the literature has shown that for extracting curcumin and piperine,
respectively, Soxhlet, microwave-assisted extraction, supercritical carbon
dioxide extraction and concentional extraction with ethanol as solvent were
used among others. According to the concentional extraction of curcumin with
ethanol important parameter like the ethanol concentration was not
investigated. In addition the maximum extraction time in this case was only 50
minutes, too short in our opinion. Due to these facts the optimum extraction
parameters for the conventional extraction of curcumin from turmeric and of
piperine from black pepper, respectively, were investigted in this study, with
respect to extraction time of 7-21 hours, ethanol concentration of 10-90 % and drug
to solvent ratio of 1:10-1:30. Response
surface methodology was used as a tool to determine the optimum conditions for
the extraction of curcumin and piperine, with help of an experimental design, central
composite design. The ideal parameter for this conventional extraction of curcumin
from turmeric and of piperine from black pepper, respectively, were an
extraction time of 15 hours, an ethanol concentration of 70 % (v/v) and a drug
to solvent ratio of 1:20.