Dietary antioxidant for disease prevention corroborated by the Nrf2 pathway

Potential use of antioxidants for the treatment of chronic inflammatory diseases

The excessive production of various reactive oxidant species over endogenous antioxidant defense mechanisms leads to the development of a state of oxidative stress, with serious biological consequences. The consequences of oxidative stress depend on the balance between the generation of reactive oxidant species and the antioxidant defense and include oxidative damage of biomolecules, disruption of signal transduction, mutation, and cell apoptosis. Accumulating evidence suggests that oxidative stress is involved in the physiopathology of various debilitating illnesses associated with chronic inflammation, including cardiovascular diseases, diabetes, cancer, or neurodegenerative processes, that need continuous pharmacological treatment. Oxidative stress and chronic inflammation are tightly linked pathophysiological processes, one of which can be simply promoted by another. Although, many antioxidant trials have been unsuccessful (some of the trials showed either no effect or even harmful effects) in human patients as a preventive or curative measure, targeting oxidative stress remains an interesting therapeutic approach for the development of new agents to design novel anti-inflammatory drugs with a reliable safety profile. In this regard, several natural antioxidant compounds were explored as potential therapeutic options for the treatment of chronic inflammatory diseases. Several metalloenzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, are among the essential enzymes that maintain the low nanomolar physiological concentrations of superoxide (O2•-) and hydrogen peroxide (H2O2), the major redox signaling molecules, and thus play important roles in the alteration of the redox homeostasis. These enzymes have become a striking source of motivation to design catalytic drugs to enhance the action of these enzymes under pathological conditions related to chronic inflammation. This review is focused on several major representatives of natural and synthetic antioxidants as potential drug candidates for the treatment of chronic inflammatory diseases.

Effect of Digested Selected Food Items on Markers of Oxidative Stress and Inflammation in a Caco-2-Based Human Gut Epithelial Model

The human gut epithelium presents a crucial interface between ingested food items and the host. Understanding how different food items influence oxidative stress and inflammation in the gut is of great importance. This study assessed the impact of various digested food items on oxidative stress, inflammation, and DNA/RNA damage in human gut epithelial cells. Differentiated Caco-2 cells were exposed to food items and their combinations (n = 22) selected from a previous study, including sausage, white chocolate, soda, coffee, orange juice, and curcumin. Following stimulation with TNF-α/IFN-1β/LPS and H2O2 for 4 h, the cells were exposed to digested food items or appropriate controls (empty digesta and medium) for a further 16 h. Cell viability, antioxidant capacity (ABTS, FRAP), IL-6, IL-8, F2-isoprostanes, lipid peroxidation (MDA), and DNA/RNA oxidative damage were assessed (3 independent triplicates). The ABTS assay revealed that cells treated with "white chocolate" and "sausage + coffee" exhibited significantly reduced antioxidant capacity compared to stimulated control cells (ABTS = 52.3%, 54.8%, respectively, p < 0.05). Similar results were observed for FRAP (sausage = 34.9%; white chocolate + sausage = 35.1%). IL-6 levels increased in cells treated with "white chocolate + sausage" digesta (by 101%, p < 0.05). Moreover, MDA levels were significantly elevated in cells treated with digested "sausage" or sausage in combination with other food items. DNA/RNA oxidative damage was found to be higher in digesta containing sausage or white chocolate (up to 550%, p < 0.05) compared to stimulated control cells. This investigation provides insights into how different food items may affect gut health and underscores the complex interplay between food components and the epithelium at this critical interface of absorption.

The effect of propolis supplementation on cardiovascular risk factors in women with rheumatoid arthritis: A double-blind, placebo, controlled randomized clinical trial

Propolis has gained popularity in recent years because of its beneficial properties, which make it a possible preventative and therapeutic agent as well as a valuable food and cosmetic ingredient. The objective of this study was to evaluate the effects of propolis supplementation on cardiovascular risk factors in women with rheumatoid arthritis. This randomized, double-blind, placebo-controlled clinical trial was performed among 48 patients diagnosed with rheumatoid arthritis. Subjects were randomly assigned to placebo and intervention groups, supplemented with 1000 mg/day of propolis for 12 weeks. Cardiovascular risk factors including, high-sensitivity C-reactive protein (hs-CRP), monocyte chemoattractant protein (MCP-1), Nitric oxide, blood pressure, and lipid profile were assessed pre-and post-intervention. The atherogenic index of plasma value, as well as total cholesterol/high-density lipoprotein cholesterol (HDL-C), triglyceride/HDL-C, and non-HDL-C/HDL-C ratios, were significantly reduced in the intervention group, compared with the placebo group post-intervention (p < 0.05). Moreover, there was a significant reduction in the serum level of hs-CRP in the intervention group when compared with the placebo group (p = 0.001). Furthermore, propolis supplementation could marginally reduce MCP-1 (p = 0.051). These data indicate that propolis supplementation may be a promising treatment strategy for cardiovascular complications among rheumatoid arthritis patients.

Revisiting carotenoids as dietary antioxidants for human health and disease prevention

Humans are unique indiscriminate carotenoid accumulators, so the human body accumulates a wide range of dietary carotenoids of different types and to varying concentrations. Carotenoids were once recognized as physiological antioxidants because of their ability to quench singlet molecular oxygen (1O2). In the 1990s, large-scale intervention studies failed to demonstrate that supplementary β-carotene intake reduces the incidence of lung cancer, although its antioxidant activity was supposed to contribute to the prevention of oxidative stress-induced carcinogenesis. Nevertheless, the antioxidant activity of carotenoids has attracted renewed attention as the pathophysiological role of 1O2 has emerged, and as the ability of dietary carotenoids to induce antioxidant enzymes has been revealed. This review focuses on six major carotenoids from fruit and vegetables and revisits their physiological functions as biological antioxidants from the standpoint of health promotion and disease prevention. β-Carotene 9',10'-oxygenase-derived oxidative metabolites trigger increases in the activities of antioxidant enzymes. Lutein and zeaxanthin selectively accumulate in human macular cells to protect against light-induced macular impairment by acting as antioxidants. Lycopene accumulates exclusively and to high concentrations in the testis, where its antioxidant activity may help to eliminate oxidative damage. Dietary carotenoids appear to exert their antioxidant activity in photo-irradiated skin after their persistent deposition in the skin. An acceptable level of dietary carotenoids for disease prevention should be established because they can have deleterious effects as prooxidants if they accumulate to excess levels. Finally, it is expected that the reason why humans are indiscriminate carotenoid accumulators will be understood soon.

The Protective Effect of Nutraceuticals on Hepatic Ischemia-Reperfusion Injury in Wistar Rats

Nutraceuticals are bioactive compounds present in foods, utilized to ameliorate health, prevent diseases, and support the proper functioning of the human body. They have gained attention due to their ability to hit multiple targets and act as antioxidants, anti-inflammatory agents, and modulators of immune response and cell death. Therefore, nutraceuticals are being studied to prevent and treat liver ischemia-reperfusion injury (IRI). This study evaluated the effect of a nutraceutical solution formed by resveratrol, quercetin, omega-3 fatty acid, selenium, ginger, avocado, leucine, and niacin on liver IRI. IRI was performed with 60 min of ischemia and 4 h of reperfusion in male Wistar rats. Afterward, the animals were euthanized to study hepatocellular injury, cytokines, oxidative stress, gene expression of apoptosis-related genes, TNF-α and caspase-3 proteins, and histology. Our results show that the nutraceutical solution was able to decrease apoptosis and histologic injury. The suggested mechanisms of action are a reduction in gene expression and the caspase-3 protein and a reduction in the TNF-α protein in liver tissue. The nutraceutical solution was unable to decrease transaminases and cytokines. These findings suggest that the nutraceuticals used favored the protection of hepatocytes, and their combination represents a promising therapeutic proposal against liver IRI.

Thymoquinone enhances the antioxidant and anticancer activity of Lebanese propolis

BACKGROUND

Reactive oxygen species (ROS) are produced by multiple cellular processes and are maintained at optimal levels in normal cells by endogenous antioxidants. In recent years, the search for potential exogenous antioxidants from dietary sources has gained considerable attention to eliminate excess ROS that is associated with oxidative stress related diseases including cancer. Propolis, a resinous honeybee product, has been shown to have protective effects against oxidative stress and anticancer effects against several types of neoplasms.

AIM

To investigate the antioxidant and anticancer potential of Lebanese propolis when applied alone or in combination with the promising anticancer compound Thymoquinone (TQ) the main constituent of Nigella sativa essential oil.

METHODS

Crude extracts of Lebanese propolis collected from two locations, Rashaya and Akkar-Danniyeh, were prepared in methanol and the total phenolic content was determined by Folin–Ciocalteu method. The antioxidant activity was assessed by the ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and to inhibit H₂O₂-induced oxidative hemolysis of human erythrocytes. The anticancer activity was evaluated by [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide] MTT assay against HCT-116 human colorectal cancer cells and MDA-MB-231 human breast cancer cells.

RESULTS

The total phenolic content of propolis extract from Rashaya and Akkar-Danniyeh were 56.81 µg and 83.503 µg of gallic acid equivalent /mg of propolis, respectively. Both natural agents exhibited strong antioxidant activities as evidenced by their ability to scavenge DPPH free radical and to protect erythrocytes against H₂O₂-induced hemolysis. They also dose-dependently decreased the viability of both cancer cell lines. The IC₅₀ value of each of propolis extract from Rashaya and Akkar-Danniyeh or TQ was 22.3, 61.7, 40.44 µg/mL for breast cancer cells at 72 h and 33.3, 50.9, 33.5 µg/mL for colorectal cancer cells at the same time point, respectively. Importantly, the inhibitory effects of propolis on DPPH radicals and cancer cell viability were achieved at half its concentration when combined with TQ.

CONCLUSION

Our results indicate that Lebanese propolis extract has antioxidant and anticancer potential and its combination with TQ could possibly prevent ROS- mediated diseases.

Independent and joint associations of dietary antioxidant intake with risk of post-stroke depression and all-cause mortality

BACKGROUND

Few observational studies have investigated the association of dietary antioxidant intake with post-stroke depression (PSD) risk. We used the cross-sectional and longitudinal design to investigate the independent and joint associations between dietary antioxidant intake and PSD risk and all-cause mortality.

METHODS

Participants from the 2005-2014 National Health and Nutrition Examination Survey (NHANES) aged 20 years and older with stroke were included. Logistic and Cox regression analyses were used to assess the associations of dietary antioxidant intake, including vitamin A, vitamin C, vitamin E, zinc, selenium, and carotenoids, and composite dietary antioxidant index (CDAI) with PSD risk and all-cause mortality.

RESULTS

The highest quartile of dietary vitamin A (OR: 0.54, 95%CI: 0.32, 0.92), total carotenoids (OR: 0.56, 95%CI: 0.34, 0.94), and selenium intake (OR: 0.53, 95%CI: 0.31, 0.90) were associated with decreased PSD risk compared with those in the lowest quartile. The results showed a negative association between CDAI and PSD risk, with the lowest OR in the third quartiles (OR: 0.49, 95%CI: 0.30, 0.83). Furthermore, the highest quartile of dietary vitamin A (HR: 0.63, 95%CI: 0.45, 0.89), vitamin E (HR: 0.69, 95%CI: 0.48, 0.99), zinc (HR: 0.57, 95%CI: 0.40, 0.81), selenium (HR: 0.64, 95%CI: 0.46, 0.90), and total carotenoids (HR: 0.66, 95%CI: 0.47, 0.92) intake and CDAI (HR: 0.56, 95%CI: 0.39, 0.81) were associated with decreased all-cause mortality compared with those in the lowest quartile.

CONCLUSION

Increased intake of dietary antioxidant may protect from depressive symptoms and improve the prognosis of stroke patients.

Optimization of Ultrasound-Assisted Extraction of Polyphenols from Ilex latifolia Using Response Surface Methodology and Evaluation of Their Antioxidant Activity

The polyphenolic extract of Ilex latifolia (PEIL) exhibits a variety of biological activities. An evaluation of the parameters influencing the ultrasonic extraction process and the assessment of PEIL antioxidant activity are presented herein. Response surface methodology (RSM) was used to optimize the experimental conditions for the polyphenols ultrasonic-assisted extraction (UAE) from the leaves of Ilex latifolia. We identified the following optimal conditions of PEIL: ethanol concentration of 53%, extraction temperature of 60 °C, extraction time of 26 min and liquid−solid ratio of 60 mL/g. Using these parameters, the UAE had a yield of 35.77 ± 0.26 mg GAE/g, similar to the value we predicted using RSM (35.864 mg GAE/g). The antioxidant activity of PEIL was assessed in vitro, using various assays, as well as in vivo. We tested the effects of various doses of PEIL on D-galactose induced aging. Vitamin C (Vc) was used as positive control. After 21 days of administration, we measured superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, malondialdehyde (MDA) levels in mouse serum and liver tissue. The results demonstrated that the PEIL exhibits potent radical scavenging activity against 1,1-diphenyl-2-picrythydrazyl (DPPH∙), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+), and hydroxyl (∙OH) radicals. The serum concentrations of SOD and GSH-Px were higher, and MDA levels were lower, in the medium- and high-dose PEIL-treated groups than those in the aging group (p < 0.01), and the activity of MDA was lower than those of the model group (p < 0.01). The liver concentrations of SOD and GSH-Px were higher (p < 0.05), and MDA levels were lower, in the medium- and high-dose PEIL-treated groups than those in the aging control group (p < 0.01). These results suggest that optimizing the conditions of UAE using RSM could significantly increase the yield of PEIL extraction. PEIL possesses strong antioxidant activity and use as a medicine or functional food could be further investigated.

From Foods to Chemotherapeutics: The Antioxidant Potential of Dietary Phytochemicals

Food plants have been recognized for their medicinal properties for millennia, a concept supported by epidemiological studies indicating long-term health benefits for people consuming greater amounts of fruits and vegetables. As our technology and instrumentation advance, researchers have the ability to identify promising phytochemicals, and examine their potential benefits, or detriments, to human health. While results from trials investigating single chemical supplementation have sometimes produced negative health results, studies investigating the synergistic action of phytochemicals—either within our diet or as an adjuvant to radiation or chemotherapy—appear promising. Utilizing phytochemicals as synergistic agents may lower the chemotherapeutic doses needed to incur physiological results, while also using chemicals with fewer toxic effects. This review investigates a variety of plant-produced chemicals humans typically ingest, their impacts on overall health patterns, molecular mechanisms associated with their health impacts, and the potential of their synergistic use for therapeutic purposes.

The Impact of Diet and Exercise on Drug Responses

It is well known that lifestyle changes can alter several physiological functions in the human body. For exercise and diet, these effects are used sensibly in basic therapies, as in cardiovascular diseases. However, the physiological changes induced by exercise and a modified diet also have the capacity to influence the efficacy and toxicity of several drugs, mainly by affecting different pharmacokinetic mechanisms. This pharmacological plasticity is not clinically relevant in all cases but might play an important role in altering the effects of very common drugs, particularly drugs with a narrow therapeutic window. Therefore, with this review, we provide insights into possible food–drug and exercise–drug interactions to sharpen awareness of the potential occurrence of such effects.

Açaí (Euterpe oleracea Martius) supplementation improves oxidative stress biomarkers in liver tissue of dams fed a high-fat diet and increases antioxidant enzymes' gene expression in offspring

Lipids excess from an uterine environment can increase free radicals production of and thus induce oxidative status imbalance, a key factor for progression of non-alcoholic fatty liver disease (NAFLD) in offspring. Food antioxidant components in maternal diet may play an important role in preventing offspring metabolic disorders. The objective of the study was to evaluate the effects of açaí pulp supplementation on maternal high-fat diet, by assessing activity and expression of antioxidant enzymes and biomarkers of oxidative stress in the liver. Female Fisher rats were divided into four groups and fed a control diet (C), a high-fat diet (HF), a control diet supplemented with açaí (CA) and a high-fat diet supplemented with açaí (HFA) before mating, during gestation and lactation. The effects of açaí supplementation on oxidative stress biomarkers and antioxidant enzymes expression were evaluated in dams and male offspring after weaning. HFA diet increased body weight in dams, however reduced absolute and relative liver weight. There was a reduction in liver biomarkers of oxidative stress, malondialdehyde and carbonyl protein, as well as in catalase, glutathione peroxidase and superoxide dismutase activity. In offspring, HFA diet reduced liver weight and increased Gpx1, Gpx4 and Sod1 mRNA expression. These results suggest that açaí is able to restore redox status, preventing oxidative damage in dams by a direct mechanism and to promote beneficial effects on expression of antioxidant defences related genes in offspring.

From winery by-product to healthy product: bioavailability, redox signaling and oxidative stress modulation by wine pomace product

The wine pomace is the main winery by-products that suppose an economic and environmental problem and their use as a functional ingredient are being increasingly recognized as a good and inexpensive source of bioactive compounds. In this sense, it is known the potential health properties of wine pomace products in the prevention of disorders associated with oxidative stress and inflammation such as endothelial dysfunction, hypertension, hyperglycemia, diabetes, obesity. Those effects are due to the bioactive compounds of wine pomace and the mechanisms concern especially modulation of antioxidant/prooxidant activity, improvement of nitric oxide bioavailability, reduction of pro-inflammatory cytokines and modulation of antioxidant/inflammatory signal pathways. This review mainly summarizes the mechanisms of wine pomace products as modulators of oxidative status involved in cell pathologies as well as their potential therapeutic use for cardiovascular diseases. For this purpose, the review provides an overview of the findings related to the wine pomace bioactive compounds profile, their bioavailability and the action mechanisms for maintaining the redox cell balance involved in health benefits. The review suggests an important role for wine pomace product in cardiovascular diseases prevention and their regular food intake may attenuate the development and progression of comorbidities associated with cardiovascular diseases.

The effect of tempeh flour from tree bean (Parkia timoriana (dc) Merr.) seeds on lipid profile in protein-energy malnutrition rats

Children with protein-energy malnutrition (PEM) need a food product that can be easily absorbed by the body because they have impaired nutrient utilization and lipid profile disorder. The provision of fermented products such as tempeh is an alternative approach. Seeds of tree bean (Parkia timoriana (DC) Merr.) are a good source of various nutrients needed by children with PEM. This study aimed to prove the effectiveness of the administration of tempeh flour from tree bean (Parkia timoriana (DC) Merr.) seeds on the lipid profile in PEM rats. PEM in rats was induced by a zero-protein diet containing granulated sugar (20 g), vegetable oil (1 g), and cornstarch (24 g). The animals were categorized into a normal control group (K+), a PEM group without treatment (K−); a group fed tempeh flour from tree bean (Parkia timoriana (DC) Merr.) seeds 1.5 g.kg-1 BW (P1); and a group fed tempeh flour from tree bean (Parkia timoriana (DC) Merr.) seeds 3 g.kg-1 BW (P2). The intervention was administered for 30 days. There was a significant increase in HDL levels (p = 0.001) and significant decreases in cholesterol (p = 0.001), triglyceride (p = 0.001), LDL levels (p = 0.001), and atherogenic index of plasma (AIP) (p = 0.000) in treatment groups. In conclusion, the administration of tempeh flour from tree bean (Parkia timoriana (DC) Merr.) seeds increases HDL levels and decreases cholesterol, triglycerides, and LDL level, and atherogenic index of plasma (AIP) in rats with PEM.

Potential Interplay between Nrf2, TRPA1, and TRPV1 in Nutrients for the Control of COVID-19

In this article, we propose that differences in COVID-19 morbidity may be associated with transient receptor potential ankyrin 1 (TRPA1) and/or transient receptor potential vanilloid 1 (TRPV1) activation as well as desensitization. TRPA1 and TRPV1 induce inflammation and play a key role in the physiology of almost all organs. They may augment sensory or vagal nerve discharges to evoke pain and several symptoms of COVID-19, including cough, nasal obstruction, vomiting, diarrhea, and, at least partly, sudden and severe loss of smell and taste. TRPA1 can be activated by reactive oxygen species and may therefore be up-regulated in COVID-19. TRPA1 and TRPV1 channels can be activated by pungent compounds including many nuclear factor (erythroid-derived 2) (Nrf2)-interacting foods leading to channel desensitization. Interactions between Nrf2-associated nutrients and TRPA1/TRPV1 may be partly responsible for the severity of some of the COVID-19 symptoms. The regulation by Nrf2 of TRPA1/TRPV1 is still unclear, but suggested from very limited clinical evidence. In COVID-19, it is proposed that rapid desensitization of TRAP1/TRPV1 by some ingredients in foods could reduce symptom severity and provide new therapeutic strategies.

Alpha lipoic acid attenuates ER stress and improves glucose uptake through DNAJB3 cochaperone

Persistent ER stress, mitochondrial dysfunction and failure of the heat shock response (HSR) are fundamental hallmarks of insulin resistance (IR); one of the early core metabolic aberrations that leads to type 2 diabetes (T2D). The antioxidant α-lipoic acid (ALA) has been shown to attenuate metabolic stress and improve insulin sensitivity in part through activation of the heat shock response (HSR). However, these studies have been focused on a subset of heat shock proteins (HSPs). In the current investigation, we assessed whether ALA has an effect on modulating the expression of DNAJB3/HSP40 cochaperone; a potential therapeutic target with a novel role in mitigating metabolic stress and promoting insulin signaling. Treatment of C2C12 cells with 0.3 mM of ALA triggers a significant increase in the expression of DNAJB3 mRNA and protein. A similar increase in DNAJB3 mRNA was also observed in HepG2 cells. We next investigated the significance of such activation on endoplasmic reticulum (ER) stress and glucose uptake. ALA pre-treatment significantly reduced the expression of ER stress markers namely, GRP78, XBP1, sXBP1 and ATF4 in response to tunicamycin. In functional assays, ALA treatment abrogated significantly the tunicamycin-mediated transcriptional activation of ATF6 while it enhanced the insulin-stimulated glucose uptake and Glut4 translocation. Silencing the expression of DNAJB3 but not HSP72 abolished the protective effect of ALA on tunicamycin-induced ER stress, suggesting thus that DNAJB3 is a key mediator of ALA-alleviated tunicamycin-induced ER stress. Furthermore, the effect of ALA on insulin-stimulated glucose uptake is significantly reduced in C2C12 and HepG2 cells transfected with DNAJB3 siRNA. In summary, our results are supportive of an essential role of DNAJB3 as a molecular target through which ALA alleviates ER stress and improves glucose uptake.

Early-Life Programming and Reprogramming of Adult Kidney Disease and Hypertension: The Interplay between Maternal Nutrition and Oxidative Stress

Kidney disease and hypertension both have attained the status of a global pandemic. Altered renal programming resulting in kidney disease and hypertension can begin in utero. Maternal suboptimal nutrition and oxidative stress have important implications in renal programming, while specific antioxidant nutrient supplementations may serve as reprogramming strategies to prevent kidney disease and hypertension of developmental origins. This review aims to summarize current knowledge on the interplay of maternal nutrition and oxidative stress in response to early-life insults and its impact on developmental programming of kidney disease and hypertension, covering two aspects. Firstly, we present the evidence from animal models supporting the implication of oxidative stress on adult kidney disease and hypertension programmed by suboptimal maternal nutrition. In the second part, we document data on specific antioxidant nutrients as reprogramming strategies to protect adult offspring against kidney disease and hypertension from developmental origins. Research into the prevention of kidney disease and hypertension that begin early in life will have profound implications for future health.

Nutraceutical Boom in Cancer: Inside the Labyrinth of Reactive Oxygen Species

In recent years, epidemiological studies have shown that food is a very powerful means for maintaining a state of well-being and for health prevention. Many degenerative, autoimmune and neoplastic diseases are related to nutrition and the nutrient-organism interaction could define the balance between health and disease. Nutrients and dietary components influence epigenetic phenomena and modify drugs response; therefore, these food-host interactions can influence the individual predisposition to disease and its potential therapeutic response. Do nutraceuticals have positive or negative effects during chemotherapy? The use of nutraceutical supplements in cancer patients is a controversial debate without a definitive conclusion to date. During cancer treatment, patients take nutraceuticals to alleviate drug toxicity and improve long-term results. Some nutraceuticals may potentiate the effect of cytotoxic chemotherapy by inducing cell growth arrest, cell differentiation, and alteration of the redox state of cells, but in some cases, high levels of them may interfere with the effectiveness of chemotherapy, making cancer cells less reactive to chemotherapy. In this review, we highlighted the emerging opinions and data on the pros and cons on the use of nutraceutical supplements during chemotherapy.

MicroRNA-mediated regulation of Nrf2 signaling pathway: Implications in disease therapy and protection against oxidative stress

MicroRNAs (miRs) are small non-coding pieces of RNA that are involved in a variety of physiologic processes such as apoptosis, cell proliferation, cell differentiation, cell cycle and cell survival. These multifunctional nucleotides are also capable of preventing oxidative damages by modulating antioxidant defense systems in a variety of milieu, such as in diabetes. Although the exact molecular mechanisms by which miRs modulate the antioxidant defense elements are unclear, some evidence suggests that they may exert these effects via nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. This intracellular mechanism is crucial in the maintenance of the physiologic redox balance by regulating the expression and activity of various cellular antioxidative defense elements and thereby plays a pivotal role in the development of oxidative stress. Any impairment in the Nrf2 signaling pathway may result in oxidative damage-dependent complications such as various diabetic complications, neurological disorders and cancer. In the current review, we discuss the modulatory effects of miRs on the Nrf2 signaling pathway, which can potentially be novel therapeutic targets.

Effect of Propolis on Diet-Induced Hyperlipidemia and Atherogenic Indices in Mice

Obesity, a major health problem worldwide, is associated with increased cardiovascular risk factors, such as dyslipidemia, glucose intolerance, and hypertension. We investigated the antioxidative capacity of the ethanol extract of propolis (EEP) and its effect on the lipid profile, the hepatorenal function, and the atherogenic indices in mice fed with a high-fat diet (HFD). EEP (50 mg/kg) was given orally to mice for 30 days. After the treatments, levels of the serum total triglyceride and cholesterol, the high density lipoprotein (HDL-c) and low density lipoprotein (LDL-c) cholesterols, the serum enzymes, and the metabolites were measured, and atherogenic indices [atherogenic index of plasma (AIP); cardiac risk ratio (CRR); cardioprotective index (CPI); atherogenic coefficient (AC)] were calculated and compared with the antioxidant, the reducing power, the radical-scavenging, and the chelating activity of EEP. The HFD diet with EEP significantly reduced the negative lipid profile and lowered AIP, CRR, and AC and increased CPI in animals on a HFD. In addition, EEP reduced the weight of mice and lipid accumulation in the liver, and it had significant in vitro antioxidative activities. The EEP possesses anti-hyperlipidemic and antioxidant activity and exhibits protective action on the cardiovascular system and hepatorenal functions. Our results contribute towards the validation of the traditional use of propolis as a food supplement in aiding hyperlipidemic disorders.