Phytochemical investigation and evaluation of the antioxidant activity of Cornus sanguinea

Cornus sanguinea L. (common dogwood) is a small tree with leaves showing a characteristic dark red colour in senescence. C. sanguinea is traditionally used for several diseases. The drupes are used as a remedy for diarrhea, stomachaches, sore eyes, sore throats, and gastrointestinal disorders, and the dried roots are used as a febrifuge. With the aim to further define the chemistry of C. sanguinea and to validate its biological activities, the methanol extract of the whole plant was investigated. The total phenolic content and the total flavonoid content of C. sanguinea extract were evaluated along with the antioxidant activity by TEAC and DPPH assays. To determine the in vitro antioxidant activity, ROS inhibition analysis was performed by DHR assay on HaCat keratinocytes cell line pre-treated with the extract. The extract displayed statistically significant activity in the range 32–125 μg/mL in the HaCat cell line stimulated with 2 mM H₂O₂. The chemical profile of the extract was investigated by an initial LC-MS analysis that guided the identification and isolation of 25 compounds, of which the structures were unambiguously elucidated by NMR analysis and LC-MS analysis as phenolic acids, flavonoids, megastigmanes, and benzofuran. This study yielded four previously unreported compounds: one megastigmane derivative and three phenolic acids. Additionally, two oxylipins were tentatively identified by LC-MS.