Beschreibung:
<jats:p>The goal of this work was to study the possibility of the occurrence of
radical- type lipid peroxidation of the lipid constituents on biomembranes,
in compressed monolayers, having lipoidal benzophenone photosensitizers
incorporated. The triplets of the photosensitizer abstract allylic and
doubly-allylic hydrogen atoms from anticonjugated moities of the lipid
molecules. The results simultaneously confirmed the occurrence of
H-abstraction (and so the initiation of the peroxidizing chain mechanism),
and the absence of the formation of lipid peroxides. The reason lies in
"cage effect": the highly restricted spacial area of compressed lipid
monolayers limits the mobility of the created radicals (lipid radicals and
ketyl radicals) and leads to their recombination, thus preventing the
propagation step of the chain mechanism. With certain reservations it may be
concluded that these results have a clear implication on real biomembranes:
the structure of which is one of themain factors preventing the spread of
the chain reaction, and the formation of lipid peroxides.</jats:p>