Rat for Evolution\

Paul Schlosser SCHLOSSER at ciit.org
Mon Jun 20 07:39:48 EST 1994


In <2tva52$a87 at panix.com>
cybrlnk at panix.com (Pietro Cappello) writes:

>Vitamin C, along with about ten thousand other molecules (vitamin E, 
>polyphenols, anti-oxidants) reacts with potential mutagens (mainly 
>electrophiles which react with the negatively charges center of DNA 
>causing base-pair mutations) and deactivates the electrophilic center, 
yes

>for example adding a hydrogen to an oxygen bonded to two adjoining C's onh 
>benzene, creating an inert alcohol. Alors, if your diet consists of none 
>of the above, your risk for mutation would sky rocket.

      C====C                                    C====C
     /      \         			       /      \
    /        \                   \            /        \ 
   C          C           -------->          C          C----OH 
   \\        / \                 /           \\        //
    \\      /   \                             \\      //
      C----C-----O                              C----C
    benzene oxide
     (putative)                                 phenol

In the case of benzene itself, the rearangement is extremely fast
(benzene oxide has never been directly observed), BUT the product
is *not* an inert alcohol.  Phenol is acutely toxic in its own right
and may be partly responsible for the hematotoxicy and subsequent incidence
of acut myelogenous leukemia that is associated with benzene exposure in
humans.
We use ascorbic acid in our incubations (benzene metabolism in suspensions
of hepatic microsomes) to suppress the auto-oxidation of phenol and,
especially, hydroqinone (a subsequent P450 metabolite)--the 1,4
hydroxy.  Otherwise, hydroquinone reacts spontaneously to semiquinone,
a free radical, which then binds irreversibly to proteins, etc.

In combination, phenol and hydroquinone are fairly hematotoxic and mutagenic.

In some cases, the alcohol is inert, but not here.

>--                        \O/ \\
>                           |  | |  <inline at maestro.com>
>Pietro Cappello           _(\_/  | <cybrlnk at panix.com>
>-----------------------------/    \--------------------
>

Paul
schlosser at beta.ciit.org



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