Two novel phenolic glycosides – citrulluside H and citrulluside T, with antioxidative activity, were recently is lated from young watermelon (Citrulluslanatus) fruits.

A new study published in Photodermatology, Photoimmunology & Photomedicine evaluated the protective effect of these compounds against UV-B-induced photo damage in normal human dermal fibroblasts (NHDFs).

In this experiment, NHDFs were exposed to UV-B irradiation at 25 mJ/cm2 . Matrix metalloproteinase (MMP)-1 and MMP-3 mRNA levels were measured by quantitative real-time PCR. MMP protein expression, as well as MAPK and NF-κB signaling was investigated by western blot analysis.

The results revealed that citrulluside H and citrulluside T significantly down regulated the protein and mRNA expression of MMP-1 and MMP-3, which are associated with the onset of skin wrinkle formation. Importantly, inhibition of UV-B-induced MMP expression in NHDFs by citrulluside H and citrulluside T was primarily due to the attenuation of MAPK/AP-1 and NF-κB signaling via scavenging of the generated ROS.

Thus, it was concluded that both, citrulluside H and citrulluside T are potential agents for alleviating UV-induced skin photoaging.

Source: Photodermatology, Photoimmunology & Photomedicine. 2021 Feb 12. doi:10.1111/phpp.12669.