## 4 Discussion
Due to the increased activity of various antioxidant enzymes, the possibility of blocking the oxidation process was also confirmed in living models [39]. Little is known about the bioactivity of juniper leaf extracts. During investigations performed by [PERSON] et al. [4], solvents of increasing polarity such as methanol, petroleum ether, chloroform, ethyl acetate, and water (MeE, PEE, ChIE, EtAE, and AqE) were used for preparation extracts from the leaves of _J. thurifera_ L. The antiradical activity of MeE, ChIE, EtAE, and AqE extracts was assessed by the DPPH assay. The three extracts of EtAE, AqE, and MeE showed high scavenging potential (IC50 = 29.348 ug/mL, 37.538 ug/mL, and 52.573 ug/mL, respectively), while the lowest antiradical activity was demonstrated by the ChIE (IC\({}_{50}\) = 70.096 ug/mL) [13]. The EtOH extract from _J. communis_ ssp. nana leaves showed the best antiradical activity against DPPH (91.40 \(\pm\) 0.54%), which was followed by the leaf EtOH extract of _J. foetidissima_ (91.21 \(\pm\) 0.45%). All of the extracts demonstrated ferric ion-chelating effect below 50% [1]. In our study, the activity antiradical activity (against ABTS free radicals; expressed as EC\({}_{50}\)) ranged from 331.64 \(\pm\) 5 (_J. ahei_) to 798.71 \(\pm\) 10 ug DE/mL (_J. sabina_) (Figure 2A). The higher chelating power was observed in the case of _J. sibrica_ (0.83 mg DE/mL) whereas the lowest was observed for _J. communis_ (3.2 mg DE/mL) (Figure 2B). The mechanisms of inflammation mediated by metabolites of lipoxygenase and nitric oxide play key roles in physiological immune response [40]. Lipoxygenases (LOXs) are enzymes involved in the production of inflammatory mediators such leukotrienes and prostaglandlandins [41]. Human LOX isoenzymes (5-, 12-, and 15-lipoxygenases) are extremely unstable at physiological temperature in the cell-free lipoxygenase assay; therefore, a good solution is to use commercially available and the physiological temperature-stable LOX derived from _Glycine max_ L. for the LOX inhibitory assay [42]. LOX inhibition is a prospective method for the treatment of inflammation [43]. Furthermore, the additional advantage of this type of experiment is avoidance of the undesirable in vivo tests on experimental animals (carrageenan-induced paw edema in rats) [44]. The LOX-inhibitory potential of pure chemicals and plant extracts is well known and extensively studied [45; 46]. Samples tested in our study are able to inhibit LOX. EC\({}_{50}\) values ranged from 1.77 to 2.44 mg DE/mL. The most effective inhibitors were extracts from _J. [PERSON]_ and _J. formozana_, whereas the lowest activity was observed in the case of _J. communis_ extract (Figure 2C). Extracts from _J. pinchotii_ and _J. excelsa_ demonstrated a non-competitive mode of action, whereas the weakest inhibitor--extract from _J. communis_--acted as a competitive LOX inhibitor (Figure 3). The extracts from _J. sibrica_ Burgsdorf. extracts demonstrated 12-LOX inhibitory activity (IC50 = 4.85 mg/mL for needles and 1.34 mg/mL for cones). The cones extract showed a better anti-inflammatory activity compared to the needles [44]. Our results indicate that all tested species exhibit a strong antioxidant activity and sufficient ability to inhibit the LOX enzyme included in inflammation processes. No correlation was found between the total phenolics content and the anti-inflammatory capacity, which suggests a synergistic effect of compounds contained in the extracts. The literature data also suggest a synergistic action of various compounds and do not attribute the biological effects (antioxidant, antifungal, or anti-inflammatory) to a single compound [6]. In the group of all assayed juniper species, the leaf extract of _Juniperus ashei_ [PERSON]. [PERSON] (mountain cedar) was distinguished as the representative with highest total polyphenol content and best antioxidant properties. To our knowledge, this is the first determination of _J. ashei_ as a juniper representative with superior antioxidant activity in the genus _Juniperus_.