It can render DNA non-amplifiable through the formation of cyclobutane
pyrimidine dimers and, to a lesser extent, what's known as the "6-4 photoproduct"; in either case, it's the creation of covalent bonds between adjacent bases on a DNA strand that disrupts their ability to hydrogenbond as needed to serve as a replication template.
Specifically, niacinamide is known to enhance DNA excision repair and repair of UVB-induced cyclobutane
pyrimidine dimers and UVA-induced 8-oxo-7,8-dihydro-2'-deoxyguanosine.
After UVA exposure bind with pyrimidine base to form cyclobutane
Ultraviolet (UV) solar radiation stimulates formation of DNA photoproducts--such as cyclobutane
pyrimidine dimers--that are highly mutagenic and DNA-altering.
UVB acts directly inducing the formation of cyclobutane
pyrimidine dimers and photoproducts (4-6).
It is an excellent photostabilizer, provides in-vivo SPF boosting by 50% for both organic and inorganic sunscreens and protects skin by inhibiting up-stream ROS cascade, namely, NADPH oxidase inhibitor, chelator and inhibitor of cyclobutane
pyrimidine dimers (CPDs) formation.
Direct absorption of UVB by cellular DNA leads to formation of cyclobutane
pyrimidine dimers and pyrimidine (6-4) pyrimidone products, while UVA is not readily absorbed by DNA, and its direct damage to DNA is therefore not important .
Topical application of alpha-tocopherol on mouse skin inhibits the formation of cyclobutane
The decrease in absorption at 345 nm was evident, which is attributed to the formation of cyclobutane
rings through [2p + 2p] cycloaddition of C=C double bond in the chalcone unit.
pyrimidine dimers determination after UV-irradiation preliminary points to 1 Coll .
is condensed to aromatic rings such as benzene, naphthalene, anthracene, and pyrene and may have different substituents such as alkyl, alkoxy, alkylthio, and aryl groups.
Firstly, UVR causes DNA mutations in skin cells via the formation of cyclobutane
pyrimidine dimers (Rochette et al.