## 4 Discussion
Similar results have been obtained by [PERSON] et al. [83], who showed that umbelliferon exhibits a pronounced antiulcerogenic effect in ethanol gastropathy. According to these authors, the umbelliferon gastoprotective effect is attributed to its antioxidant action. In other experimental studies, the conjugate of diclofenac with umbelliferon (which has fewer ulcerogenic side effects) showed pronounced anti-inflammatory and antioxidant properties [84]. Numerous studies indicate that various coumarins have pronounced antiradical properties with respect to the 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl stable free radical (DPPH\({}^{\bullet}\)), superoxide anion (O\({}_{2}^{-}\)), hydroxyl radical (OH\({}^{\bullet}\)), and ABTS\({}^{\bullet+}\) radical. Umbelliferon prevents \(\beta\)-carotene oxidation in a model system with linoleic acid, and it can inhibit peroxidation induced by 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH), which is a producer of free radicals. Some coumarins also exhibit their antioxidant activity through iron ion chelation. Iron is an essential element and cofactor responsible for the electron transport chain function and catalytic processes. However, excessive iron accumulation can lead to the overproduction of reactive oxygen species (ROS), which can lead to cell membrane damage, necrosis, and possibly cell death. Among the coumarin derivatives, umbelliferone and scopoletin are iron-binding chelators that inhibit iron-catalyzed ROS formation and protect cells from damage [85; 86; 87; 88]. Owing to the coumarin antioxidant properties, vascular endothelium cell membrane integrity is preserved, which prevents the desquamation of endothelicocytes, their fragments, and cell layers. In addition, coumarins (which exhibit antiaggregatory properties owing to the inhibition of thromboxane A2 and B2 synthesis [89; 90]) can inhibit the adhesion and aggregation of platelets and erythrocytes in places where the endothelium base membrane is exposed [88; 91; 92; 93]. By influencing the reduction of intracellular calcium concentration in the smooth myocytes of microvasculature vessels, coumarins have a vasodilating effect [89]. The ability of coumarins to inhibit platelet aggregation and improve blood rheological properties [94], in combination with its vasodilating effect, prevents angiospasm and increases local blood supply [88; 94]. In turn, effective microcirculation is an important condition for the normal functioning of the gastric mucosa's protective factors. Thus, an increase in blood flow in the gastric mucosa is accompanied by a parallel increase in acidity, and the gastric mucosa is more resistant to acid in the acid production zone than in other locations [95; 96; 97; 98]. Coumarins affect vascular endothelial growth factor expression and fibroblast growth factors, thereby controlling growth and new vessel formation, and affecting proliferation and fibroblast migration for synthesizing collagen and glycosaminoglycans in the extracellular matrix; this leads to increased regeneration and the accelerated formation of granulation tissue [99]. In accordance with the literature, scopoletin and umbelliferone (which exhibit a dual inhibitory activity against COX-2 and 5-LO [100]) suppress the synthesis of inflammatory mediators (histamine and serotonin), pro-inflammatory cytokines (IL-1\(\beta\), TNF-\(\alpha\)), leukotrienes, and other biological substances, which decreases the microvasculature vessel permeability and prevents blood plasma exudation, local edema development, blood cell migration, and infiltrated cell development [88; 89; 101; 102; 103]. In addition, coumarins reduce myeloperoxidase concentration and suppress neutrophil chemotaxis [92; 104]. The reduced gastric mucosa inflammation is accompanied by an increase in somatostatin secretion and a reduction in gastrin secretion. By controlling the level of gastrin, somatostatin also regulates hydrochloric acid secretion [105], accelerating ulcer healing and reducing relapse risk. Thus, skimmin and peuencidin from _F.