Photoprotective effects of quercetin on photoaging-induced rats

Photoaging is characterised by cutaneous changes caused by exposure to ultraviolet light over time. Quercetin is a bioflavanoid with antioxidant, antineoplastic, and anti-inflammatory effects. This study investigated the therapeutic effects of topical quercetin on photoaging, a phenomenon not previously studied in ultraviolet A (UVA)-induced photoaging.

A total of 40 rats were randomly categorised into 5 groups, each comprising 8 rats. A photoaging model was induced by applying UVA to the dorsal region of all rats, except for the negative control group. Topical 0.1% retinoic acid was applied to one UVA group, topical 0.3% quercetin to another UVA group, and both agents were applied in combination to yet another UVA group 5 days a week for 8 weeks. Subsequently, wrinkle values were measured, reactive oxygen species (ROS) and matrix metalloproteinase-1 (MMP-1) levels were analysed, and histopathological parameters were examined.

The wrinkle value of the UVA group was found to be significantly higher than that of the UVA + Quercetin group. Collagen damage was lower in the UVA + Quercetin group than in the UVA group, although this difference was not statistically significant. Compared with the UVA + Retinoic Acid group, the UVA + Quercetin group exhibited a more significant decrease in inflammation. MMP-1 values were considerably higher in the UVA + Retinoic Acid and UVA + Quercetin + Retinoic Acid groups as well as in the UVA + Quercetin group compared with the control and UVA groups.

The present study showed that quercetin can be utilised in the treatment of photoaging, especially when combined with retinoic acid.