## 1 Introduction  
Deciphering the existing links between oro-dental diseases and those that evolve at a distance from the oral cavity is very important. The understanding of these phenomena opens new perspectives in identifying the most effective means of treatment both for oro-dental affections and for those at a distance from this area. Thus, clinical studies have revealed that periodontal disease is correlated with atherosclerosis and cardiovascular diseases, with statistics showing that there is a high risk of acute myocardial infarction in patients with periodontitis [1; 2]. The common element in the etiopathogenesis of these diseases is oxidative stress, as well as the consecutive production of large amounts of reactive oxygen species (ROS), which are the basis of functional changes and systemic inflammatory processes. _Lysimachia nummularia_ L. is part of the _Primulaceae_ family, _Myrsinaceae_ subkingdom, and is a perennial herbaceous plant (common name: coin plant) that has proven to be a valuable source of bioactive compounds with therapeutic potential, including phenolic compounds [3; 4]. The literature mentions the use of plants belonging to the _Primula_ family in traditional medicine for various ailments, without specifying exactly the bioactive compounds responsible for the amelioration or healing effects on the disease. Thus, the use of these plants is recommended in different illnesses, such as stomatitis, gingivitis, periodontitis, rheumatic pain, gastro-intestinal diseases [5], hepato-biliary stones, urination [6], nephritis edema, damp jaundice [6; 7; 8], swelling and edema [9] and viral infections with hepatitis E virus [10], due to their anthelmintic [5], diuretic, detoxifying [6], analgesic [11], antibacterial, antitumor [12; 13] and antioxidant [6; 14; 15] effects. According to the specialized literature, the antioxidant properties of the species _Lysimachia nummularia_ L. are attributed to secondary metabolites, namely phenolic compounds, especially flavonic glycosides [5; 9] and triterpen saponins [11; 16], which were detected in the chemical composition of species, as well as flavonoids [5; 8; 17] and other phenolic compounds, with the exception of caffeic acid derivatives, ferulic acid, chlorogenic acid, p-coumaric acid [18] and gallic acid [19]. Polyphenols are organic compounds that have intense antioxidant activity; therefore, they are used to combat oxidative stress, to detoxify the body, to reduce degenerative phenomena, to prevent tumor processes, neuroprotection, etc. [20; 21]. Although they can be obtained synthetically, polyphenolic compounds obtained from plants have higher bioavailability and better activity. Phenolic compounds represent the largest group of natural polyphenols. They are mainly found in the leaves, seeds, stems, fruits, bark, flowers and other parts of plants. Specialists discuss their anticancer potential via inhibiting the activity of enzymes involved in the neovascularization process. Phenolic compounds are associated with estrogen secretion in the female body, prevent infections, have antialergic properties and are characterized by hepatoprotective, cholertic and antiulcer properties [22; 23]. The antioxidant activity of various plant products that belong to the species _Lysimachia nummularia_ L. has also been investigated by in vitro methods, namely with 1,1-diphenyl-2-picrylhydrazyl (DPPH) [5]; with 2,2\({}^{2}\)-azinobis-(3-ethylbenzothazoline-6-sulfonate) (ABTS) from the aerial parts, flowers and roots [5; 9]; the DPPH and ferric reducing antioxidant power assay (FRAP) from the aerial parts of _Lysimachia verticillaris_[19]; and the DPPH and Trolox equivalent antioxidant capacity (TEAC) assay in the aerial parts of _Lysimachia nummularia_ L. [18]. The presence of phenolic acids such as _trans_-resveratrol or 3-\(O\)-methylgallic acid has not been mentioned in the specialized literature.