Determination of in vitro photoprotection on human skin fibroblasts and keratinocytes after UVA and UVB radiation by aqueous and ethanolic extracts from Stellaria media herb

There is a growing need for substances exhibiting antioxidant activity, which may protect the skin against UV-induced cellular damage and photoageing. Stellaria media (Linn.) Vill. (Caryophyllaceae) is common weed used as food and medicinal plant. Extracts are applied topically onto the skin, to treat dermatological diseases. Because of that, and the presence of polyphenols in the herb, we evaluated the protective effect of water and ethanol extracts (most commonly used in medicine) derived from the Stellaria media herb on skin fibroblasts and keratinocytes against UVA and UVB radiation.

Cells were pre-incubated with tested extracts (25 – 200 µg/mL) and then irradiated with UVA (25 and 50J/cm²) or UVB (250 and 500 mJ/cm²). Intracellular ROS production, proliferative activity, lactate dehydrogenase release and apoptosis after UV-irradiation were measured.

The results showed that the aqueous extracts from Stellaria herb decreased intracellular ROS production in a concentration-dependent manner. However, extract only moderately increased cell proliferation inhibited by UV and decreased cytotoxicity. Moreover, aqueous extract decreased the number of cells in late apoptosis (annexin V-FITC and propidium iodide positive). In contrary, ethanolic extract increased UV-induced cytotoxicity, despite of the similar antioxidative activity as aqueous extract.

Our results show, that aqueous extract of Stellaria media may be effective as photoprotector, because of ROS generation inhibiting activity, and partially explain the use of extract in skin diseases, such as sunburns.