In vitro antioxidant properties of herb decoction extracts derived from Epirus, Greece

For thousands of years, medicinal herbs have been an integral part of traditional medicine, since a number of them exhibit potent antioxidant properties, mainly associated with their rich content in bioactive compounds. Based on these attributes, nowadays, medicinal herbs are used for industrial purposes (e.g., as natural food additives) and are also evaluated as chemopreventive strategies for diseases associated with the disruption of redox homeostasis. In that frame, the aim of the present study was to appraise the redox properties of various medicinal or edible herbs originating from the region of Epirus in Greece. The antioxidant, reducing and antigenotoxic effects of herb decoction extracts were evaluated using a series of in vitro cell‑free assays. Whereupon, non‑cytotoxic concentrations of the four most potent herb decoction extracts (i.e., Origanum vulgare, Salvia officinalis, Aloysia citrodora and Rosmarinus officinalis) were used to treat EA.hy926 endothelial cells, and the glutathione (GSH) and reactive oxygen species (ROS) levels were determined using flow cytometry in order to detect the potential changes induced in the intracellular redox equilibrium. The results indicated that apart from the Rosmarinus officinalis decoction extract, which did not induce any changes following treatment, the decoction extracts of Origanum vulgare (50 µg/ml) and Salvia officinalis (10 and 20 µg/ml) induced a significant decrease in GSH levels compared with the controls, while the decoction extract of Aloysia citrodora was the most bioactive, inducing a significant decrease in GSH levels at all concentrations used (5, 10 and 20 µg/ml). On the whole, the tested herb decoction extracts exhibited a potent antioxidant capacity. In addition, the most robust of these were able to disrupt the antioxidant mechanisms of the EA.hy926 cell line, as revealed by the depletion of the intracellular GSH levels, rendering them promising contenders for further studies.