Fisetin-d5 is a deuterium-labeled form of Fisetin. Found naturally in various fruits and vegetables, Fisetin is a flavonol known for its beneficial properties, including antioxidant, anticancer, and neuroprotective effects.

Treating UVB-exposed mice with Fisetin leads to a reduction in hyperplasia and a decrease in the infiltration of inflammatory cells. Fisetin treatment also reduces inflammatory mediators such as COX-2, PGE2, and its receptors (EP1-EP4), as well as MPO activity. Furthermore, Fisetin lowers the levels of inflammatory cytokines TNFα, IL-1β, and IL-6 in UVB-exposed skin. It also diminishes cell proliferation markers and DNA damage, as evidenced by increased expression of p53 and p21 proteins.