Hypericum olympicum L. recovers DNA damage and prevents MMP–9 activation induced by UVB in human dermal fibroblasts

Ethnopharmacological relevance: Hypericum olympicum L. (Hypericaceae) flowering aerial parts has been utilized in Turkish folk medicine as a remedy against inflamed skin problems. Aim of the study: This study was designed to state the effect of H. olympicum on dermatological problems. For this purpose effect of the plant extract on the DNA strand break and matrix metalloproteinase (MMP)–9 activity of human dermal fibroblast (HDFs) cells irradiated with UVB as well as antioxidant activity potential were studied. Materials and methods: The methanolic extract of Hypericum olympicum (HOM) was prepared by maceration at room temperature. DNA damage and increased MMP–9 activity in HDFs were induced by UVB irradiation. The cell viability was measured by water–soluble tetrazolium salt (WST)–1 assay. The effects on DNA strand break was investigated by single gel electrophoresis (commonly known as Comet assay), while MMP–9 activity was observed by gelatin zymography assay. In vitro antioxidant tests were performed to indicate the effect on reactive oxygen species (ROS). The major metabolites were identified and their concentrations were measured by high performance thin layer chromatography (HPTLC). Results: HOM was found to recover DNA damage dose–dependently. The enzymatic activity of MMP–9 was inhibited almost 100% by the treatment of 1.5 mg/mL of the extract. It also enhanced cell proliferation in those cells, and also it was shown to possess antioxidant activity. The major metabolites of HOM were identified as chlorogenic acid and quercetin glycosides (rutin, hyperoside, isoquercitrin). Conclusion: Experimental studies have proven the traditional use of Hypericum olympicum in inflamed skin problems acting by inhibition of the inflammatory pathway and recovery of DNA damage induced experimentally.