الفهرس 
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Abstract
I’ Because of their special properties, the cyanines (methines) as a class of
organic compounds are interested not only for the chemist, but also for numerous
other scientists working in the fields of biology, medical science, technology and
physics.
The cyanine structure contains two heterocyclic rings linked by a simple
methine chain containing an odd number of carbon atoms. The nature of the terminal
heterocyclic ring incorporated into cyanine dyes markedly affects the chromophoric
character (Le. colour) of the cyanine dye, as does the changing length or substituents
in the polyrnethine chain.
Classification of cyanines (Hamer, 1964):
Cyanine dyes are conveniently classified according to the number of -
CH=(methine, methylidine or methenyl) groups in the chain between the two ring
systems and according to the ring system present. If one methine group is present, the
dye is classified as monomethine or simple cyanine. If there are 3 methine groups, the
dye is classified as trimethine or carbocyanine. Dyes with 5 methine groups are known
as pentarnethines or dicarbocyanines, and dyes with 7 methine groups are known as
heptamethines or tricarbocyanines.
In the present investigation 3 types of monomethine (simple) cyanine dyes were used.
Cyanine dyes have many biological and biochemical effects. Attempts have
been made to systematically relate the electro-chernical properties of cyanine dyes with
their biological actions. Control of electrochemical potentials in biochemical reactions
could provide new ways of limiting abnormal or infectious cell growth in disease. A
strong relation was found between the reduction potential of a cyanine dye and its
ability to inhibit cell division. Some of the cyanine dyes are growth inhibitors to
bacteria, and to the mitosis of fertilized sea urchin eggs (Zigmand et aI., 1980,
Gilman et aI., 1981).