The Influence of Different Oregano Species on the Antioxidant Activity Determined Using HPLC Postcolumn DPPH Method and Anticancer Activity of Carvacrol and Rosmarinic Acid

The aim of this study was to evaluate concentration-dependent antioxidant and anticancer activities of CA and RA in ethanol extracts of three different Oregano species (Origanum onites L., Origanum vulgare L., and Origanum vulgare ssp. hirtum). The study revealed the highest RA antioxidant activity in O. vulgare ssp. hirtum (9550 ± 95 mmol/g) and the lowest in O. vulgare L. (2605 ± 52 mmol/g) (p < 0.05). The highest CA amount was present in O. onites L., which was 1.8 and 4.7 times higher (p < 0.05) than in O. vulgare ssp. hirtum and O. vulgare L., respectively. The anticancer activity was evaluated on human glioblastoma (U87) and triple-negative breast cancer (MDA-MB231) cell lines in vitro. RA anticancer activity was negligible. CA and the extracts were about 1.5–2 times more active against MDA-MB231 cell line (p < 0.05) compared to U87 cell line. The anticancer activities of three tested extracts were similar against U87 cell line (p > 0.05) but they had different activities against MDA-MB231 cell line.