Evening primrose (Oenothera L.) is a plant belonging to the family Onagraceae, in which the most numerous species is Oenothera biennis. Some plants belonging to the genus Oenothera L. are characterized by biological activity. Therefore, studies were conducted to determine the dependence of biological activity on the chemical composition of various parts of the evening primrose, mainly leaves, stems, and seeds. Common components of all parts of the Oenothera biennis plants are fatty acids, phenolic acids, and flavonoids. In contrast, primrose seeds also contain proteins, carbohydrates, minerals, and vitamins. Therefore, it is believed that the most interesting sources of biologically active compounds are the seeds and, above all, evening primrose seed oil. This oil contains mainly aliphatic alcohols, fatty acids, sterols, and polyphenols. Evening primrose oil (EPO) is extremely high in linoleic acid (LA) (70–74%) and γ-linolenic acid (GLA) (8–10%), which may contribute to the proper functioning of human tissues because they are precursors of anti-inflammatory eicosanoids. EPO supplementation results in an increase in plasma levels of γ-linolenic acid and its metabolite dihomo-γ-linolenic acid (DGLA). This compound is oxidized by lipoxygenase (15-LOX) to 15-hydroxyeicosatrienoic acid (15-HETrE) or, under the influence of cyclooxygenase (COX), DGLA is metabolized to series 1 prostaglandins. These compounds have anti-inflammatory and anti-proliferative properties. Furthermore, 15-HETrE blocks the conversion of arachidonic acid (AA) to leukotriene A₄ (LTA₄) by direct inhibition of 5-LOX. In addition, γ-linolenic acid suppresses inflammation mediators such as interleukin 1β (IL-1β), interleukin 6 (IL-6), and cytokine - tumor necrosis factor α (TNF-α). The beneficial effects of EPO have been demonstrated in the case of atopic dermatitis, psoriasis, Sjögren’s syndrome, asthma, and anti-cancer therapy.

Chronic exposure of the skin to solar UV radiation induces a number of biological alterations, including a redox imbalance; therefore, there is an urgent need for skin cells protective compounds. The aim of this study was to determine the effects of natural, previously extensively examined, polyphenol with antioxidant properties - rutin, on UV-induced skin fibroblasts membrane disruption. Accordingly, fibroblasts exposed to UVA and UVB irradiation were incubated with rutin (12h before and/or up to 24h after irradiation), and the structural and metabolic changes were examined. Rutin penetration through the fibroblast phospholipid bilayer was aided by UVA-induced bilitranslocase activity 2-4h after irradiation, while UVB irradiation led to enhanced phospholipid peroxidation and higher membrane permeability to facilitate the interaction of rutin with phospholipids. Lipidomic analysis revealed that 4h of rutin treatment also partially prevented UVA/B-induced increase in phosphatidylethanolamine and phosphatidylcholine level, as well as their membrane localization, which resulted in an enhanced zeta potential in the cells and liposomes. Moreover, rutin 2h following irradiation, in a various degree, prevented the increased in phospholipase A2 activity and ROS generation, and partially protected against the reduction of arachidonic and linoleic acids level and the lipid peroxidation product 4-hydroxynonenal level increase. Rutin effectively prevented against decrease in glutathione peroxidase, glutathione and vitamins E and C activities/levels, particularly 2h following UVA irradiation. In conclusion, highest skin fibroblasts membrane level of rutin occurred in 2-4h following UVA/B-radiation results in its strongest effect on biomembrane structure and functions and cellular antioxidant system irrespective of the radiation type.

Proximal mechanisms describing the evolution of high levels of basal metabolic rate (BMR) in endotherms are one of the most intriguing problems of evolutionary physiology. Because BMR mostly reflects metabolic activity of internal organs, evolutionary increase in BMR could have been realized by an increase in relative organ size and/or mass-specific cellular metabolic rate. According to the "membrane pacemaker" theory of metabolism, the latter is mediated by an increase in the average number of double bonds (unsaturation index) in cell membrane fatty acids. To test this, we investigated the effect of divergent artificial selection for body-mass-corrected BMR on the mass of internal organs and the fatty acid composition of cell membranes in laboratory mice (Mus musculus). Mice from the high-BMR line had considerably larger liver, kidneys, heart, and intestines. In contrast, the unsaturation index of liver cell membranes was significantly higher in low-BMR mice, mainly because of the significantly higher content of highly polyunsaturated 22 : 6 docosahexanoic fatty acid. Thus, divergent selection for BMR did not affect fatty acyl composition of liver and kidney phospholipids in the direction predicted by the membrane pacemaker theory. We conclude that an intraspecific increase in BMR may rapidly evolve mainly as a result of the changes in size of internal organs, without simultaneous increase of the unsaturation index in cell membrane lipids.

Primary and secondary hypertension is associated with kidney redox imbalance resulting in enhanced reactive oxygen species (ROS) and enzymes dependent phospholipid metabolism. The fatty acid amide hydrolase inhibitor, URB597, modulates the levels of endocannabinoids, particularly of anandamide, which is responsible for controlling blood pressure and regulating redox balance. Therefore, this study aimed to compare the effects of chronic URB597 administration to spontaneously hypertensive rats (SHR) and rats with secondary hypertension (DOCA-salt rats) on the kidney metabolism associated with the redox and endocannabinoid systems. It was shown fatty acid amide hydrolase (FAAH) inhibitor decreased the activity of ROS-generated enzymes what resulted in a reduction of ROS level. Moreover varied changes in antioxidant parameters were observed with tendency to improve antioxidant defense in SHR kidney. Moreover, URB597 administration to hypertensive rats decreased pro-inflammatory response, particularly in the kidneys of DOCA-salt hypertensive rats. URB597 had tendency to enhance ROS-dependent phospholipid oxidation, estimated by changes in neuroprostanes in the kidney of SHR and reactive aldehydes (4-hydroxynonenal and malondialdehyde) in DOCA-salt rats, in particular. The administration of FAAH inhibitor resulted in increased level of endocannabinoids in kidney of both groups of hypertensive rats led to enhanced expression of the cannabinoid receptors type 1 and 2 in SHR as well as vanilloid receptor 1 receptors in DOCA-salt rats. URB597 given to normotensive rats also affected kidney oxidative metabolism, resulting in enhanced level of neuroprostanes in Wistar Kyoto rats and reactive aldehydes in Wistar rats. Moreover, the level of endocannabinoids and cannabinoid receptors were significantly higher in both control groups of rats after URB597 administration. In conclusion, because URB597 disturbed the kidney redox system and phospholipid ROS-dependent and enzymatic-dependent metabolism, the administration of this inhibitor may enhance kidney disorders depending on model of hypertension, but may also cause kidney disturbances in control rats. Therefore, further studies are warranted.

The mechanisms of biological activity of commonly used natural compounds are constantly examined. Therefore, the aim of this study was to compare ascorbic acid efficacy in counteracting the consequences of UV and hydrogen peroxide treatment on lipid mediators and their regulative action on antioxidant abilities. Skin fibroblasts exposed to UVA and UVB irradiation, treated with hydrogen peroxide and ascorbic acid. The redox system was estimated through reactive oxygen species (ROS) generation (electron spin resonance spectrometer) and antioxidants level/activity (HPLC/spectrometry) which activity was evaluated by the level of phospholipid metabolites: 4-hydroxynonenal, malondialdehyde, 8-isoprostanes and endocannabinoids (GC/LC-MS) in the human skin fibroblasts. Protein and DNA oxidative modifications were also determined (LC). The expression of nuclear factor erythroid 2-related factor 2 (Nrf2), its activators and inhibitors as well as pro/anti-apoptotic proteins and endocannabinoid receptors was examined (Western blot) and collagen metabolism was evaluated by collagen biosynthesis and prolidase activity (spectrometry). UVA and UVB irradiation and hydrogen peroxide treatment enhanced activity of xanthine and NADPH oxidases resulting in ROS generation as well as diminution of antioxidant phospholipid protection (glutathione peroxidase-glutathione-vitamin E), what led to increased lipid peroxidation and decreased endocannabinoids level. Dysregulation of cannabinoid receptors expression and environment of transcription factor Nrf2 caused apoptosis induction. Ascorbic acid partially prevented ROS generation, antioxidant capacity diminution and endocannabinoid systems disturbances but only slightly protected macromolecules such as phospholipid, protein and DNA against oxidative modifications. However, ascorbic acid significantly prevented decrease in collagen type I biosynthesis. Ascorbic acid in similar degree prevents UV (UVA and UVB) and hydrogen peroxide-dependent redox imbalance. However, this antioxidant cannot efficiently protect cellular macromolecules and avert metabolic dysregulation leading to apoptosis.

Fatty acids participate in different metabolic mechanisms, but their key role is connected with their participation in membrane phospholipid organizations. This review introduces the current knowledge of fatty acid analysis with an emphasis on the analysis of these compounds in biological samples. Therefore this manuscript is focused on various aspects of biological sample preparation methods, such as lipid extraction, lipid and phospholipid fractionation (TLC and SPE), derivatization, and on the methodologies of fatty acid analysis by gas chromatography (GC) and high-performance liquid chromatography (HPLC). The wide spectrum of columns and detectors used in these techniques for selective separation and determination of bioactive fatty acids are discussed. The abilities of using a sensitive tandem LC/MS and GC/MS assay are also shown.