The decomposition of cardiolipin hydroperoxide generates triplet carbonyls that transfer energy to triplet oxygen and thus form singlet oxygen .
Energy transfer from (14) to triplet oxygen converts the latter to [sup.1][O.sub.2] and the former to its ground state form (16), whose reaction with hydrogen peroxide regenerates (14) and forms singlet oxygen [44, 88, 90].
The AOPs are based on oxidizing radicals, mainly hydroxyl radicals, while other radicals and active oxygen species such as superoxide radical anions (*O2 ), hydroperoxy radicals (HO2 ), triplet oxygen
(3O2) and organic peroxyl radicals (R-O-O*) are also involved .
Ideally the trapping compound should meet certain conditions such as being water soluble, highly reactive with singlet oxygen, and unreactive with other oxygen species such as triplet oxygen
([sup.3][O.sub.2]), superoxide radical anion ([O.sub.2.sup.*-]) or hydrogen peroxide ([H.sub.2][O.sub.2]) (18).
Singlet molecular oxygen due to spin multiplicity changes and transforms to triplet oxygen
through a relaxation process.
The singlet oxygen can be produced through the energy transfer process from the triplet state of the photosensitizer to the triplet oxygen
ABLADE will aim is demonstrate the efficacy of a novel photo-therapy based on the stimulation of triplet oxygen
at a cellular level which can initiate cell apotosis specifically in tumour cells.
Polyphenols are able to neutralize free radicals, scavenge singlet and triplet oxygen
, and to break down peroxides.
For example singlet oxygen can be produced by a reaction between the dissolved triplet oxygen
and the excited triplet state of erythrosine B.
is a good energy acceptor and it can be excited to its singlet state by energy transfer from a photosensitizer.
Nevertheless, both UVA and UVB as well as visible light convert various photosensitizing compounds to excited states which transfer energy to triplet oxygen, thereby generating reactive oxygen species, particularly singlet oxygen.
The triplet carbonyls can transfer energy to triplet oxygen, thereby generating singlet oxygen .