Flavonoids
Oral genistein has also been shown to reduce carcinogenesis
induced by UV-B radiation in animal models.28 Furthermore,
oral administration of quercetin reduces the systemic
oxidative stress produced when the animals are exposed to
either UV-B79 or UV-A80 radiation.
P leucotomos Extract
In humans, consumption of single doses of P leucotomos
extract not only has an antioxidant effect and inhibits the
lipid peroxidation of cutaneous cell membranes,81 but it
also reduces UV-induced inflammation,82,83 prevents the
isomerization of trans-urocanic acid to its cis form,49 and
protects against radiation-induced immunosuppression.84 A
particularly important effect of oral P leucotomos extract is
the induction and activation of the p53 gene, which directly
accelerates removal of DNA photoproducts, especially the
highly mutagenic thymine dimers. P leucotomos extract
has also been shown to prevent DNA oxidative damage,
inhibiting the conversion of guanosine to 8-deoxyguanosine
and reducing UV-induced mutagenesis.81