Grape Seed Procyanidins Attenuates Cisplatin-induced Human Embryonic Renal Cell Cytotoxicity by Modulating Heme Oxygenase-1 in Vitro

Proanthocyanidin alleviates testicular torsion/detorsion-induced ischemia/reperfusion injury in rats

Testicular torsion is an urological emergency and can lead to ischemia damage and testicular loss if not diagnosed in time. Proanthocyanidin is reported to have anti-inflammatory and antioxidant properties. The current study aimed to examine the possible effects of proanthocyanidin (P) on the testis in torsion/detorsion (T/D)-induced testicular ischemia/reperfusion (I/R) injury in rats. Forty rats were divided into four groups (n=10 for each): sham-operated (sham), I/R, I/R + P100 (100 mg/kg, 30 min before torsion), and I/R + P200 (200 mg/kg, 30 min before torsion). Testicular T/D was performed on the left testicle by 3 hours of torsion at 720° clockwise, followed by 3 hours of detorsion. In the I/R group, an increase in malondialdehyde (MDA) levels and a decrease in glutathione (GSH), vitamin C (Vit C), glutathione peroxidase (GPx), glucose-6-phosphate dehydrogenase (G6PD) values were determined compared to the sham group (p<0.001). Moreover, an increase in the expression of cleaved caspase-3 and Bcl2-associated X protein (Bax), a decrease in the expression of B-cell lymphoma 2 (Bcl-2) and proliferating cell nuclear antigen (PCNA) were detected in the I/R group (p<0.001). Histopathologically, it was determined that the Johnsen and Cosentino scores of the testicles were irregular in the I/R group (p<0.001). Proanthocyanidin treatment caused a decrease in MDA, cleaved caspase-3 and Bax levels and an increase in GSH, Vit C, GPx, G6PD, Bcl-2 and PCNA values. Additionally, Johnsen and Cosentino rearranged the scores. The present findings revealed the protective and curative effects of proanthocyanidin in organ damage due to testicular torsion/detorsion-induced ischemia/reperfusion with their antioxidative and antiapoptotic properties.

Selected Seeds as Sources of Bioactive Compounds with Diverse Biological Activities

Seeds contain a variety of phytochemicals that exhibit a wide range of biological activities. Plant-derived compounds are often investigated for their antioxidant, anti-inflammatory, immunomodulatory, hypoglycemic, anti-hypercholesterolemic, anti-hypertensive, anti-platelet, anti-apoptotic, anti-nociceptive, antibacterial, antiviral, anticancer, hepatoprotective, or neuroprotective properties. In this review, we have described the chemical content and biological activity of seeds from eight selected plant species-blackberry (Rubus fruticosus L.), black raspberry (Rubus coreanus Miq.), grape (Vitis vinifera L.), Moringa oleifera Lam., sea buckthorn (Hippophae rhamnoides L.), Gac (Momordica cochinchinensis Sprenger), hemp (Cannabis sativa L.), and sacha inchi (Plukenetia volubilis L). This review is based on studies identified in electronic databases, including PubMed, ScienceDirect, and SCOPUS. Numerous preclinical, and some clinical studies have found that extracts, fractions, oil, flour, proteins, polysaccharides, or purified chemical compounds isolated from the seeds of these plants display promising, health-promoting effects, and could be utilized in drug development, or to make nutraceuticals and functional foods. Despite that, many of these properties have been studied only in vitro, and it's unsure if their effects would be relevant in vivo as well, so there is a need for more animal studies and clinical trials that would help determine if they could be applied in disease prevention or treatment.

Oxidative Stress and NRF2/KEAP1/ARE Pathway in Diabetic Kidney Disease (DKD): New Perspectives

Diabetes mellitus (DM) is one of the most debilitating chronic diseases worldwide, with increased prevalence and incidence. In addition to its macrovascular damage, through its microvascular complications, such as Diabetic Kidney Disease (DKD), DM further compounds the quality of life of these patients. Considering DKD is the main cause of end-stage renal disease (ESRD) in developed countries, extensive research is currently investigating the matrix of DKD pathophysiology. Hyperglycemia, inflammation and oxidative stress (OS) are the main mechanisms behind this disease. By generating pro-inflammatory factors (e.g., IL-1,6,18, TNF-α, TGF-β, NF-κB, MCP-1, VCAM-1, ICAM-1) and the activation of diverse pathways (e.g., PKC, ROCK, AGE/RAGE, JAK-STAT), they promote a pro-oxidant state with impairment of the antioxidant system (NRF2/KEAP1/ARE pathway) and, finally, alterations in the renal filtration unit. Hitherto, a wide spectrum of pre-clinical and clinical studies shows the beneficial use of NRF2-inducing strategies, such as NRF2 activators (e.g., Bardoxolone methyl, Curcumin, Sulforaphane and their analogues), and other natural compounds with antioxidant properties in DKD treatment. However, limitations regarding the lack of larger clinical trials, solubility or delivery hamper their implementation for clinical use. Therefore, in this review, we will discuss DKD mechanisms, especially oxidative stress (OS) and NRF2/KEAP1/ARE involvement, while highlighting the potential of therapeutic approaches that target DKD via OS.

Proanthocyanidins Activate Nrf2/ARE Signaling Pathway in Intestinal Epithelial Cells by Inhibiting the Ubiquitinated Degradation of Nrf2

Nrf2 plays a key role in the antioxidant system, and many antioxidants can activate the Nrf2/ARE signaling pathway and alleviate oxidative stress. However, the underlying mechanisms of antioxidants, such as proanthocyanidin- (PC-) induced Nrf2 activation, remain poorly understood. In this study, PC was used on MODE-K cells at different concentrations (0, 1, 2.5, and 5 μg/mL) and different times (0, 3, 6, 12, and 24 h); then, immunoprecipitation, immunofluorescence, and Western blotting were performed to test Nrf2, Bach1, Keap1, HO-1, and NQO1 protein expressions in MODE-K cells. Results showed that PC increased Nrf2, HO-1, and NQO1 protein expressions, decreased Keap1 and Bach1 protein expressions, and enhanced ARE gene activity. PC also decreased the ubiquitinated degradation of the Nrf2 protein, increased Nrf2 protein stability, and increased Nrf2 protein expression by inhibiting Keap1-dependent Nrf2 protein degradation, promoted Nrf2 entry into the nucleus, competed with Bach1, and activated ARE elements, which in turn initiated the Nrf2/ARE signaling pathway. Thus, we conclude that PC activates the Nrf2/ARE signaling pathway in intestinal epithelial cells by inhibiting the ubiquitinated degradation of Nrf2, increasing Nrf2 protein stability and expression, and then regulating key antioxidant enzymes such as HO-1 and NQO1 to initiate cytoprotective effects.

Antioxidant and Neuroprotective Effect of a Grape Pomace Extract on Oxaliplatin-Induced Peripheral Neuropathy in Rats: Biochemical, Behavioral and Histopathological Evaluation

Oxaliplatin is a widely used chemotherapeutic agent. Despite its many beneficial aspects in fighting many malignancies, it shares an aversive effect of neuropathy. Many substances have been used to limit this oxaliplatin-driven neuropathy in patients. This study evaluates the neuroprotective role of a grape pomace extract (GPE) into an oxaliplatin induced neuropathy in rats. For this reason, following the delivery of the substance into the animals prior to or simultaneously with oxaliplatin, their performance was evaluated by behavioral tests. Blood tests were also performed for the antioxidant activity of the extract, along with a histological and pathological evaluation of dorsal root ganglion (DRG) cells as the major components of the neuropathy. All behavioral tests were corrected following the use of the grape pomace. Oxidative stressors were also limited with the use of the extract. Additionally, the morphometrical analysis of the DRG cells and their immunohistochemical phenotype revealed the fidelity of the animal model and the changes into the parvalbumin and GFAP concentration indicative of the neuroprotective role of the pomace. In conclusion, the grape pomace extract with its antioxidant properties alleviates the harmful effects of the oxaliplatin induced chronic neuropathy in rats.

Grape Seed Extract Positively Modulates Blood Pressure and Perceived Stress: A Randomized, Double-Blind, Placebo-Controlled Study in Healthy Volunteers

It is well established that maintaining healthy blood pressure is fundamental in order to avoid disorders to the heart and blood vessels. In prevention, and alongside pharmacological therapy, the use of natural substances has been proven to be extremely helpful for pre- and mild hypertensive subjects. Our study was therefore focused on the effects, both in vitro and in humans, of a grape seed extract, Enovita (GSEe), a highly standardized extract in polyphenols of Vitis vinifera L. The in vitro human umbilical vein endothelial cells (HUVEC) model was chosen to explore the extract properties related to vascular inflammation/vasodilation. A significant reduction of both soluble Inter-Cellular Adhesion Molecule-1 (sICAM) and endothelin-1 secretion/release was induced by GSEe in HUVEC cells. A randomized, double-blind, placebo-controlled clinical study in healthy volunteers was further performed to investigate GSEe benefits. In healthy volunteers, both supplementations significantly modulated blood pressure, with a pronounced effect after GSEe tablets (300 mg/day for 16 weeks) in respect to placebo. In the male gender subgroup, no placebo effect was observed as it was for the female group. As an additional outcome, an overall GSEe positive modulation emerged on mood related to stress perception. Thus, GSEe resulted in a benefit of modulating endothelial functionality and blood pressure. It was noteworthy that GSEe relieved the perceived stress, promising new future perspectives on mood comfort.

Natural Antioxidants Improve the Vulnerability of Cardiomyocytes and Vascular Endothelial Cells under Stress Conditions: A Focus on Mitochondrial Quality Control

Cardiovascular disease has become one of the main causes of human death. In addition, many cardiovascular diseases are accompanied by a series of irreversible damages that lead to organ and vascular complications. In recent years, the potential therapeutic strategy of natural antioxidants in the treatment of cardiovascular diseases through mitochondrial quality control has received extensive attention. Mitochondria are the main site of energy metabolism in eukaryotic cells, including myocardial and vascular endothelial cells. Mitochondrial quality control processes ensure normal activities of mitochondria and cells by maintaining stable mitochondrial quantity and quality, thus protecting myocardial and endothelial cells against stress. Various stresses can affect mitochondrial morphology and function. Natural antioxidants extracted from plants and natural medicines are becoming increasingly common in the clinical treatment of diseases, especially in the treatment of cardiovascular diseases. Natural antioxidants can effectively protect myocardial and endothelial cells from stress-induced injury by regulating mitochondrial quality control, and their safety and effectiveness have been preliminarily verified. This review summarises the damage mechanisms of various stresses in cardiomyocytes and vascular endothelial cells and the mechanisms of natural antioxidants in improving the vulnerability of these cell types to stress by regulating mitochondrial quality control. This review is aimed at paving the way for novel treatments for cardiovascular diseases and the development of natural antioxidant drugs.

Grape seed proanthocyanidins improves mitochondrial function and reduces oxidative stress through an increase in sirtuin 3 expression in EA.hy926 cells in high glucose condition

Proanthocyanidins are phenolic compounds abundant in the diet, commonly found in grapes and derivatives, foods known for their health-promoting benefits. There is previous evidence showing the antidiabetic activity of proanthocyanidins, however, their mechanisms of action have not been fully elucidated. This study evaluated the capacity of grape seed proanthocyanidins extract (GSPE) to modulate oxidative stress, nitric oxide levels, mitochondrial dysfunction, apoptosis, and sirtuin expression in endothelial cells EA.hy926 under high glucose condition. In addition, the possible toxic effects of GSPE was evaluated in a zebrafish embryos model. The results showed that GSPE was able to enhance cell viability and avoid the disturbance in redox metabolism induced by high glucose. Moreover, GSPE was able to avoid mitochondria dysfunction and the increased in p53 and poly-(ADP-ribose) polymerase expression induced by high glucose exposition. These effects were attributed to the increase in expression of sirtuin 3, a protein able to regulate mitochondrial function. GSPE in an effective concentration did not show toxic effects in zebrafish embryos model. Taken together, these data elucidate the key molecular target of GSPE for future pharmacological interventions in diabetic patients.

Protective Effect of Astaxanthin on Ochratoxin A-Induced Kidney Injury to Mice by Regulating Oxidative Stress-Related NRF2/KEAP1 Pathway

The present study aimed to investigate the effects of astaxanthin (ASX) on ochratoxin A (OTA)-induced renal oxidative stress and its mechanism of action. Serum kidney markers, histomorphology, ultrastructural observation, and oxidative stress indicators were assessed. Meanwhile, quantitative real-time reverse transcription PCR and western blotting detection of NRF2 (encoding nuclear factor, erythroid 2 like) and members of the NRF2/KEAP1 signaling pathway (KEAP1 (encoding Kelch-like ECH-associated protein), NQO1 (encoding NAD(P)H quinone dehydrogenase), HO-1 (encoding heme oxygenase 1), γ-GCS (gamma-glutamylcysteine synthetase), and GSH-Px (glutathione peroxidase 1)) were performed. Compared with the control group, the OTA-treated group showed significantly increased levels of serum UA (uric acid) and BUN (blood urea nitrogen), tubular epithelial cells were swollen and degenerated, and the levels of antioxidant enzymes decreased significantly, and the expression of NRF2 (cytoplasm), NQO1, HO-1, γ-GCS, and GSH-Px decreased significantly. More importantly, after ASX pretreatment, compared with the OTA group, serum markers were decreased, epithelial cells appeared normal; the expression of antioxidant enzymes increased significantly, NQO1, HO-1, γ-GCS and GSH-Px levels increased significantly, and ASX promoted the transfer of NRF2 from the cytoplasm to the nucleus. These results highlight the protective ability of ASX in renal injury caused by OTA exposure, and provide theoretical support for ASX’s role in other mycotoxin-induced damage.