Bioactivity Potential of Aesculus hippocastanum L. Flower: Phytochemical Profile, Antiradical Capacity and Protective Effects on Human Plasma Components under Oxidative/Nitrative Stress In Vitro

Horse chestnut (Aesculus hippocastanum) flower is a traditional medicine applied to alleviate symptoms of chronic venous insufficiency (CVI). However, its flavonoid-based composition has not been sufficiently recognized, and the data supporting its traditional application are lacking. In the work, 43 constituents were detected by UHPLC–PDA–ESI–TQ–MS/MS (flavonoids, phenolic acids, flavanols, and coumarins), including 31 reported in the flower for the first time. The quantitative HPLC–PDA study (developed and validated for quality control purposes) indicated the fractionated extraction as an efficient method for enhancing the total polyphenol content (TPHC) in the extracts (up to 414.06 mg/g) and kaempferol glycosides as their dominant constituents (75.05–82.14% TPHC). The activity studies showed significant scavenging properties of the extracts and their constituents towards reactive oxygen species (especially against highly reactive hydroxyl radical, with capacities up to 7.85 mmol ascorbic acid equivalents/g). Moreover, the analytes relevantly protected human plasma biomolecules from peroxynitrite-induced oxidative/nitrative damage; at 1–50 µg/mL, they hindered the protein nitration and lipid peroxidation, decreasing the levels of 3-nitrotyrosine (by up to 50%) and thiobarbituric acid reactive substances (by up to 70%), respectively. The extracts also averted the depletion of plasma thiols (by up to 67%) and improved the non-enzymatic antioxidant capacity of plasma. The demonstrated mechanisms might be partly responsible for the efficacy of the flower in CVI. Additionally, the anti-aggregatory and anticoagulant properties of the extracts were found only mild or negligible, which suggests that they may be safely applied with drugs impacting the coagulation process.

Endothelial PHD2 Deficiency Induces Nitrative Stress via Suppression of Caveolin-1 in Pulmonary Arterial Hypertension

Nitrative stress is a characteristic feature of the pathology of human pulmonary arterial hypertension (PAH). However, the role of nitrative stress in the pathogenesis of obliterative vascular remolding and severe PAH remains largely unclear. Our recent studies identified a novel mouse model (Egln1Tie2Cre, Egln1 encoding prolyl hydroxylase 2 [PHD2]) with obliterative vascular remodeling and right heart failure, which provides us an excellent model to study the role of nitrative stress in obliterative vascular remodeling. Here we show that nitrative stress was markedly elevated whereas endothelial Caveolin-1 (Cav1) expression was suppressed in the lungs of Egln1Tie2Cre mice. ROS scavenger manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin pentachloride (MnTmPyP) treatment inhibited obliterative pulmonary vascular remodeling and suppressed severe PAH in Egln1Tie2Cre mice. Genetic restoration of endothelial Cav1 expression in Egln1Tie2Cre mice normalized nitrative stress, reduced PAH and improved right heart function. These data suggest that suppression of endothelial Cav1 expression secondary to PHD2 deficiency augments nitrative stress, which contributes to obliterative vascular remodeling and severe PAH. Thus, ROS scavenger might have great therapeutic potential for the inhibition of obliterative vascular remodeling and severe PAH.

Nickel nanoparticles induce hepatotoxicity via oxidative and nitrative stress-mediated apoptosis and inflammation

Nickel nanoparticles (Ni NPs) are utilized extensively in various industrial applications. However, there are increasing concerns about potential exposure to Ni NPs and consequent health effects. The aim of this study was to assess Ni NPs-induced liver toxicity in Sprague Dawley rats. Twenty-five rats were exposed to Ni NPs via intraperitoneal injection at doses of 15, 30, and 45 mg/kg per body weight for 28 days. Results from ICP-MS analysis showed an increase in the concentration of Ni NPs in a dose-dependent manner. The liver dysfunction was indicated by considerable production of ALT, AST, ALP, LDH, and TB in Ni NPs-treated rats. Histological examination demonstrated liver injuries (inflammatory cells, congestion, necrosis, and pyknosis) in exposed rats with dose-dependent severity of pathologies by semi-quantitative histograding system. To explore the toxicological pathways, we examined oxidative stress biomarkers and detected Ni NPs significantly elevated the levels of MDA and LPO while decreasing the levels of CAT and GSH. All the changes in biomarkers were recorded in a dose-dependent relationship. In addition, we found upregulated NF-kβ indicating activation of inflammatory cytokines. ELISA results of serum revealed a remarkable increase of nitrative stress markers (iNOS and NO), ATPase activity, inflammatory cytokine (IL-6, IL-1β, and TNF-α), and apoptotic mediators (caspase-3 and caspase-9) in Ni NPs-treated groups than the control. In summary, the result of this study provided evidence of hepatotoxicity of Ni NPs and insightful information about the involved toxic pathways, which will help in health risk assessment and management, related preventive measures for the use of Ni-NPs materials.

Ellagic Acid Prevents Binge Alcohol-Induced Leaky Gut and Liver Injury through Inhibiting Gut Dysbiosis and Oxidative Stress

Alcoholic liver disease (ALD) is a major liver disease worldwide and can range from simple steatosis or inflammation to fibrosis/cirrhosis, possibly through leaky gut and systemic endotoxemia. Many patients with alcoholic steatohepatitis (ASH) die within 60 days after clinical diagnosis due to the lack of an approved drug, and thus, synthetic and/or dietary agents to prevent ASH and premature deaths are urgently needed. We recently reported that a pharmacologically high dose of pomegranate extract prevented binge alcohol-induced gut leakiness and hepatic inflammation by suppressing oxidative and nitrative stress. Herein, we investigate whether a dietary antioxidant ellagic acid (EA) contained in many fruits, including pomegranate and vegetables, can protect against binge alcohol-induced leaky gut, endotoxemia, and liver inflammation. Pretreatment with a physiologically-relevant dose of EA for 14 days significantly reduced the binge alcohol-induced gut barrier dysfunction, endotoxemia, and inflammatory liver injury in mice by inhibiting gut dysbiosis and the elevated oxidative stress and apoptosis marker proteins. Pretreatment with EA significantly prevented the decreased amounts of gut tight junction/adherent junction proteins and the elevated gut leakiness in alcohol-exposed mice. Taken together, our results suggest that EA could be used as a dietary supplement for alcoholic hepatitis patients.

Vitamin D Deficiency and Gender Alter Vasoconstrictor and Vasodilator Reactivity in Rat Carotid Artery

The vitamin-D-sensitivity of the cardiovascular system may show gender differences. The prevalence of vitamin D (VD) deficiency (VDD) is high, and it alters cardiovascular function and increases the risk of stroke. Our aim was to investigate the vascular reactivity and histological changes of isolated carotid artery of female and male rats in response to different VD supplies. A total of 48 male and female Wistar rats were divided into four groups: female VD supplemented, female VDD, male VD supplemented, male VDD. The vascular function of isolated carotid artery segments was examined by wire myography. Both vitamin D deficiency and male gender resulted in increased phenylephrine-induced contraction. Acetylcholine-induced relaxation decreased in male rats independently from VD status. Inhibition of prostanoid signaling by indomethacin reduced contraction in females, but increased relaxation ability in male rats. Functional changes were accompanied by VDD and gender-specific histological alterations. Elastic fiber density was significantly decreased by VDD in female rats, but not in males. Smooth muscle actin and endothelial nitric oxide synthase levels were significantly lowered, but the thromboxane receptor was elevated in VDD males. Decreased nitrative stress was detected in both male groups independently from VD supply. The observed interactions between vitamin D deficiency and sex may play a role in the gender difference of cardiovascular risk.

Oxidative stress parameters as biomarkers of bladder cancer development and progression

The epidemiological studies confirm that the overproduction of free radical is an important factor of cancer induction as well as development, and loss of antioxidant systems efficiency is associated with an increased risk of carcinogenesis. While bladder cancer is the fourth most common type of cancer all over the world, there is little evidence of the advancing changes in oxidative/nitrative stress during the progression of bladder cancer. Our study aimed to investigate the plasma levels of typical markers of oxidative/nitrative stress depending on the clinical classification of bladder cancer differentiation and infiltration degree. We examined 40 patients with newly diagnosed bladder cancer and 20 healthy volunteers as a control group. We analysed the plasma levels of protein carbonyls, thiol groups, 3-nitrotyrosine, lipid peroxidation, as well as non-enzymatic plasma antioxidant capacity using DPPH· and ABTS·+ radicals. We confirmed that all analysed biomarkers are higher in enrolled BC patients than in healthy subjects. Furthermore, our findings demonstrate a positive correlation between the degree of bladder cancer progression and the level of oxidative stress, but no correlation in the case of NT-3. Based on obtained results, we might conclude that during carcinogenesis of the bladder increased oxidative damage of biomolecules is manifested. This indicates the participation of oxidative stress in the development of bladder cancer, and it is important the ensure the proper antioxidant protection.