The condensed extractor
drips into the thimble containing the turmeric
rhizomes powder, and extracts it by
contact. When the level of liquid in chamber
rises to the top of siphon tube, the liquid contents
of chamber flood into flask. This
process is continuous and is carried out until
a drop of solvent from the siphon tube does
not leave residue when evaporated. After 3
days, the solvent is evaporated by rotary apparatus.
Then, it is dissolved in 100 mL toluene.
The solution is poured into separatory
funnel. Then, 100 mL NaOH 0.2 M is added
to the solution and shaked for minutes. The
aqueous phase is collected and acidified to
pH 3 by HCl 0.2 M. The brown extract undergoes
a clarification in this step and turns
yellow. The filtrate is extracted with diethyl
ether (3 × 100 mL). In the final extraction,
the ether turns to a very pale yellow, indicating
the end of the extraction. The combined
ethereal phases are washed with 30 mL water
and dried over MgSO4. The ether is removed
completely in vacuum to leave a yellow solid
as crude curcuminoid products (Scheme 1)
[16]. The crude curcumin (Scheme 1C) is
purified by thin layer chromatography (208
mg). The product (Figure 2) was chromatographed