The immune response is essential in the protection of our body against pathogens; however, the inflammatory response caused by the immune system can become a disease itself. In fact, anti-inflammatory and immune-suppressive drugs are applied to limit the immune response to treat inflammatory diseases. Flavonoids are plant-derived polyphenols extensively investigated for their anti-inflammatory and antioxidant properties in inflammatory diseases. Studies applying isolated compounds as well as using supplements as nutraceuticals based on flavonoids have been conducted. Our review systematically analyzed the top five studied flavonoids between 2020 and 2025: quercetin (1742 articles), kaempferol (642), luteolin (589), apigenin (419), and epicatechin (354), highlighting their major therapeutic applications in diseases affecting the liver (12%), nervous system (11%), and lungs (10%). Mechanistically, these compounds act as multi-target agents mainly by inhibiting NF-κB and inducing Nrf2-dependent antioxidant programs. Application of advanced delivery systems, which increase oral bioavailability by up to 20-fold, overcomes pharmacokinetic bottlenecks. Clinical highlights demonstrated promising therapeutic effects, including reduced intrahepatic lipid accumulation in non-alcoholic fatty liver disease patients following quercetin supplementation (11.5% to 9.6%) and accelerated SARS-CoV-2 clearance after quercetin phytosome administration. The translation of flavonoids into standardized clinical therapies remains limited by the lack of large-scale, well-controlled clinical trials.

Ultraviolet B (UVB) irradiation, with wavelengths ranging from 290 to 320 nm, represents a biologically active fraction of solar irradiation that reaches the Earth’s surface and exerts significant effects on human skin. Due to its high energy, UVB penetrates the epidermis and directly interacts with cellular components, particularly DNA, leading to the formation of photoproducts such as cyclobutane pyrimidine dimers. In parallel, UVB exposure induces the generation of reactive oxygen species, promoting oxidative stress and damage to lipids, proteins, and genetic material. These events activate key intracellular signaling pathways, including NF-κB and MAPKs, resulting in the production of pro-inflammatory mediators that amplify cutaneous inflammation. In addition to classical inflammatory and oxidative mechanisms, emerging evidence highlights the role of neuroimmune interactions in the skin, involving crosstalk between nerve endings, neuropeptides, and immune cells, which contributes to the regulation of local immune responses following UVB exposure. The integration of these processes plays a central role in the pathophysiology of UVB-induced skin damage and in the development of skin diseases. This review will discuss the molecular and cellular mechanisms underlying the cutaneous response triggered by UVB irradiation, with emphasis on inflammation, oxidative stress, and neuroimmune communication. Additionally, current and emerging therapeutic strategies based on pathophysiology mechanisms, including antioxidant agents, anti-inflammatory compounds, and photoprotective approaches, will be discussed to highlight potential avenues for improved prevention and treatment of UVB-induced skin damage.