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

Abstract

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.

Effects of boric acid and potassium metaborate on cytokine levels and redox stress parameters in a wound model infected with methicillin‑resistant Staphylococcus aureus

“…Geyikoglu et al ( 40 ) demonstrated that boric acid decreased the 8-OHdG expression level in ischemia reperfusion injury by acting as an antioxidant, anti-inflammatory and antiapoptotic agent. The results of TAC, TOS and LDH assays supported the results from the 8-OHdG staining assay ( 41 , 42 ).…”

Evaluation of the antioxidant potency of Greek honey from the Taygetos and Pindos mountains using a combination of cellular and molecular methods

“…Cell-free methods are reliable as a preliminary screening of the effectiveness of the tested samples; therefore, further investigations using cell lines may provide information regarding the bioavailability, the metabolism and the uptake of the antioxidants constituents of the honey ( 69 ). The use of cell-based methods can also be used to examine the potential toxic or protective mechanisms ( 48 ). In the present study, a liver cancer cell line (HepG2) was used for several reasons.…”

“…GSH is the most abundant endogenous antioxidant, playing crucial roles in the detoxification and metabolic processes ( 71 ). GSH has the ability to donate a hydrogen atom from its sulfhydryl group, thus scavenging the free radicals and other electrophiles either directly or indirectly used as a substrate by antioxidant enzymes ( 48 , 72 ). In the present study, the honey samples did not induce the production of GSH in HepG2 cells, apart from the oak honey.…”

“…For the measurement of intracellular ROS levels, the cells stained were with the DCF-DA fluorescent dye. Esterases found inside of the cells deacetylate DCF-DA, which is then further transformed into fluorescent DCF by the oxidative action of ROS ( 48 ). The cells were incubated in the presence of DCF-DA 10 µM (of 400 µM stock), at 37°C for 30 min under dark conditions, followed by trypsinization and centrifugation (300 × g, 5 min, 4°C) to wash the excessive fluorescent and resuspension in PBS.…”

Evaluation of the effects of a honey‑based gel on blood redox biomarkers and the physiological profile of healthy adults: A pilot study

“…Additionally, evidence in the literature has also widely debated the chemo-preventive, immunoregulatory, antioxidant and antiatherogenic properties of honey (58)(59)(60)(61). Nevertheless, information regarding the properties of Greek honey in literature and notably from in vivo studies are scarce even though Greece is part of the eastern Mediterranean, creating a rich and diversified flora habitat (62,63). This rich flora biodiversity combined with the overflowing sunshine, creates an ideal environment resulting in a variety of honey types originating from pine, thyme, fir and other conifers (64,65).…”