## 3 Discussion
A number of studies have demonstrated a good correlation of intrinsic antioxidant activity in a non-cellular assay with cytoprotection against an oxidant challenge in a cellular assay, demonstrating the ability of antioxidants to act intracellularly [43; 44]. Cellular protection of _Roe_x towards H\({}_{2}\)O\({}_{2}\) pre-treatment, was evaluated against both cancer and non-cancer cell line, adenocarcinoma breast cancer cells MDA-MB-231 and mouse fibroblasts NIH3T3, respectively (Figure 4). According to data reported in literature [45], _Roe_x was able to increase significantly NIH3T3 cell viability after pre-treatment with H\({}_{2}\)O\({}_{2}\) concentrations ranging from 0.33 and 1.3 mM but not at highest values, i.e., 1.5 and 1.6 mM (Figure 4a). Human adenocarcinoma breast cells demonstrated to be more resistant to H\({}_{2}\)O\({}_{2}\) pre-treatment in comparison to NIH3T3 fibroblasts and the rosmarinic extract improved cell viability neutralizing the toxic effect of H\({}_{2}\)O\({}_{2}\) also at the highest concentrations (from 0.82 to 1.6 mM), demonstrating to be able to protect cells and to reduce cell death (Figure 4b). The importance of rosmarinic and hydrocynnamic derivative to protect cells in H\({}_{2}\)O\({}_{2}\)-induced cytotoxicity is well known. Rosmarinic acid exhibited substantial H\({}_{2}\)O\({}_{2}\) scavenging activity and inhibited H\({}_{2}\)O\({}_{2}\)-induced intracellular ROS production [44]. Caffeic acid was found to scavenge intracellular reactive oxygen species, and 1,1-diphenyl-2-picrylhydrazyl radical, and thus prevented lipid peroxidation. Chlorogenic acid protect cells against H\({}_{2}\)O\({}_{2}\)-induced oxidative stress and apoptosis [45]. Intracellular dose-dependent uptake of flavonoids has been demonstrated in various cell types in vitro and is believed to be even higher in vivo than under normal culture conditions [16]. In vitro antiproliferative activity of _Roe_x towards NIH3T3 and MDA-MB-231, noncancer and cancer cells, respectively, was evaluated by NRU test. The NRU results showed that _Roe_x exerted a weak anti-proliferative effect against both NIH3T3 and MDA-MB-231 cell lines in a concentration dependent manner, with lesser efficiency on breast adenocarcinoma cells compared to fibroblasts (Figure 3). In particular, the concentration value of 2.4 \(\times\) 10\({}^{-1}\) mg/mL reduced NIH3T3 viability by 50%, while the same effect with MDA-MB-231 was obtained at a _R_oex concentration of 4.8 \(\times\) 10\({}^{-1}\) mg/mL, a higher value in comparison to data reported in literature where MDA-MB-231 cells proliferation is inhibited in a dose-dependent manner with an IC\({}_{50}\) of about 2.04 \(\times\) 10\({}^{-2}\) mg/mL [46]. The antiproliferative effect of rosemary extracts towards cancer cells is influenced by their constituents and seems to be correlated with the presence of polyphenols, mainly caffe and rosmarinic acid [47]. On the contrary, rosmarinic and caffeic acid demonstrated low cytotoxicity against non-cancer cells [48] and this could explain the weak antiproliferative activity of rosemary extract against non-cancer NIH3T3 cells. A genotoxicity study is a key step for risk assessment during development of natural plant extracts for human applications because various genotoxic compounds can cause a DNA damage compromising human health [49]. In the bacterial reverse mutation assay (Ames test) performed on _R_oex, as expected, the positive control agents significantly induced genotoxicity but no genotoxic positive result was observed in _R_oex treated groups compared to control at any of the tested concentrations (Table 4). These results indicate that _R_oex and their phytochemical components, did not exhibit any genotoxic risk under the experimental conditions of this study. The preclinical evaluation of the antithrombotic potential of novel molecules requires the use of reliable reproducible experimental models. TT is one of the most commonly used tests to determine the efficacy of novel antithrombotic drugs.