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					Summary                                                                 III

                                  Summary
This thesis includes four chapters:
      Chapter one is an introduction to Phytochemistry with a general
literature survey about the natural pigments. It also deals with a survey for
the sweet cherry (Prunus avium L.) fruit.
      Chapter two deals with the extraction of pigments (quercetin) and
(cyanidin-3-glucoside) with ultrasound assistance (for 1 hour) from the
Iraqi Kurdistan cherry fruit. Different solvents were used during 24 hours
at room temperature, the best solvent was found to be 80% methanol which
gave the highest extract yield (15.95%). The extracted pigments were
purified using chemical and physical methods including different
chromatographic techniques (TLC, PTLC, and column chromatography).
The pure extracted pigments were identified using HPLC and different
spectroscopic    techniques       such     as   infrared,   ultraviolet-visible
                     1            13
spectrophotometry,       H-NMR,        C-NMR and elemental analysis. The
purified pigments were hydrolyzed to identify attached sugar.
      The biological activity of the extracted pigments were determined
against two common types of bacteria which were Staphylococcus aureus
(gram +ve) and Escherichia coli (gram –ve), the results indicates that the
anthocyanin compound (cyanidin-3-glucoside) has inhibited each types of
bacteria.
      Chapter three describes the stability of the extracted pigment
(cyanidin-3-glucoside) towards the solvents, temperature and pH effects
and this pigment was applied as a very useful indicator in visual acid-base
titration in aqueous medium. Double detection devices; spectrophotometer
and potentiometer were simultaneously used in this titration. This indicator
was accurate and precise for three types of neutralization titration: strong
acid-strong base, strong acid-weak base and weak acid-weak base titration,
Summary                                                                 IV

while for the titration of weak acid against strong base the value of relative
error was more than 30%.

      Chapter four deals with a new and simple flow injection analysis
with chemiluminescence (CL) system for determination of quercetin
through the reverse flow injection technique. The method was based on the
inhibition of the CL of H2O2–luminal-permanganate with quercetin which
is systematically decreased the CL-intensity with increasing the
concentration of quercetin. The reverse flow was used to avoid continuous
monitors of CL which leads to unstable baseline. Various parameters
associated with this flow system were studied and essential optimizations
were carried out. Two calibration graphs were constructed for
determination of quercetin in the range (6.0–12 μg/ml) with correlation
coefficient (0.9994) for low concentration level and (20–190 μg/ml) with
correlation coefficient (0.9962) for high concentration and a sampling
frequency 80 samples/h. Possible interferences were studied and the results
showed that the interferences caused less than 5% error. The method was
applied successfully for the determination of quercetin in various natural
products.

				
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posted:5/10/2010
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