Role Of Natural Antioxidants Research Articles

The role of natural anti-oxidants in gut microbiota alteration subsequent to high fat diet (HFD)

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): PON-MIUR 000_78 Evidence exists that the gut microbiota contributes to the alterations of lipid metabolism associated with high-fat diet (HFD). Moreover, the gut microbiota has been found to modulate the metabolism and absorption of dietary lipids, thereby affecting the formation of lipoproteins occurring at the intestinal level as well as systemically, though the pathophysiological implication of altered microbiota composition in HFD and its role in the development of atherosclerotic vascular disease (ATVD) remain to be better clarified. Recently, evidence has been collected indicating that supplementation with natural polyphenols and fibres accounts for an improvement of HFD-associated intestinal dysbiosis, thereby leading to improved lipidaemic profile. This study aimed to investigate the protective effect of a bergamot polyphenolic extract (BPE) containing 48% polyphenols enriched with albedo and pulp-derived micronized fibres (BMF) in the gut microbiota of HFD-induced dyslipidaemia. In particular, rats that received an HFD over a period of four consecutive weeks showed a significant increase in plasma cholesterol, triglycerides and plasma glucose compared to a normal-fat diet (NFD) group. This effect was accompanied by body weight increase and alteration of lipoprotein size and concentration, followed by high levels of MDA, a biomarker of lipid peroxidation. Treatment with a combination of BPE plus BMF (50/50%) resulted in a significant reduction in alterations of the metabolic parameters found in HFD-fed rats, an effect associated with increased size of lipoproteins. Furthermore, the effect of BPE plus BMF treatment on metabolic balance and lipoprotein size re-arrangement was associated with reduced gut-derived lipopolysaccharide (LPS) levels, an effect subsequent to improved gut microbiota as expressed by modulation of the Gram-negative bacteria Proteobacteria, as well as Firmicutes and Bacteroidetes. This study suggests that nutraceutical supplementation of HFD-fed rats with BPE and BMP or with their combination product leads to restored gut microbiota, an effect associated with lipoprotein size re-arrangement and better lipidaemic and metabolic profiles.

Antioxidative and Cytoprotective Effects of Ganoderma applanatum and Fomitopsis pinicola in PC12 Adrenal Phaeochromocytoma Cells.

Considering the impact of oxidative stress on the development of many diseases, together with the role of natural antioxidants in maintaining physiological balance in humans, medicinal mushrooms are potential sources of bioactive compounds against many diseases. In the present work, in vitro evaluation of the biological activities of the alcoholic extracts of two wild tree mushrooms, namely, Ganoderma applanatum and Fomitopsis pinicola, has been performed. Extraction of G. applanatum (GAE) and F. pinicola (FPE) was conducted with 60% ethanol and 100% ethanol sequentially. UPLC-MS/MS identification was conducted on the two mushrooms extracts. A total of 15 substances were identified in GAE, including 3 spiro meroterpenoids and 12 triterpenoids; a total of 14 chemical constituents were iden¬tified in FPE, including 8 triterpenoids, 4 triterpene glycosides, 1 lanosterol, and 1 lanostanoid. The resulting extracts were examined for their in vitro antioxidative and cytoprotective effects against AAPH-induced oxidative damage. Our results demonstrated that both extracts have potent antioxidative activities, when GAE was 0.2 mg/mL, the clearance rates of DPPH and ABTS have reached 93.34% and 99.93%, respectively. When FPE was 1.4 mg/mL and 0.6 mg/mL, the scavenging rates of DPPH and ABTS have reached 91.76% and 100%, respectively. Both the alcoholic extracts of G. applanatum and F. pinicola were able to protect the AAPH-induced damage and could effectively inhibit cell aging via β-galactosidase (SA β-gal) staining activity test and scanning electron microscopy analysis.

Oxidative Status and Insulin Resistance in Diabetic Retinopathy: Effect of Natural Antioxidants

The homeostatic model assessment (HOMA) Index was found to be increased both in uncomplicated diabetes mellitus and in diabetic retinopathy indicating the degrees of insulin resistance. Malondialdehyde as a biomarker for oxidative stress has also been found in these groups with a decreased tolerance to glucose load. When these groups were further analyzed and compared according to their insulin status, it was observed that hyperinsulinemia in diabetic retinopathy enhanced the level of oxidative stress with a decrease in plasma ascorbic acid and an increase of plasma dehydroascorbic acid level, paralleling the levels of malondialdehyde in these patients. The role of natural antioxidants e.g. ascorbic acid, Vitamin E and mixed carotenoids in lessening insulin has been discussed. It seems that ascorbic acid is a better antioxidant in comparison to other antioxidants in normalization of insulin resistance and glucose utilization. A persistent long-standing insulin resistance has been suggested as one of the responsible factors for vascular complications in diabetic retinopathy. Dehydroascorbic acid seems to be a better sensitive biomarker for oxidative stress.

Regulation of miRNAs by Natural Antioxidants in Cardiovascular Diseases: Focus on SIRT1 and eNOS.

Cardiovascular diseases (CVDs) are the most common cause of morbidity and mortality worldwide. The potential benefits of natural antioxidants derived from supplemental nutrients against CVDs are well known. Remarkably, natural antioxidants exert cardioprotective effects by reducing oxidative stress, increasing vasodilation, and normalizing endothelial dysfunction. Recently, considerable evidence has highlighted an important role played by the synergistic interaction between endothelial nitric oxide synthase (eNOS) and sirtuin 1 (SIRT1) in the maintenance of endothelial function. To provide a new perspective on the role of natural antioxidants against CVDs, we focused on microRNAs (miRNAs), which are important posttranscriptional modulators in human diseases. Several miRNAs are regulated via the consumption of natural antioxidants and are related to the regulation of oxidative stress by targeting eNOS and/or SIRT1. In this review, we have discussed the specific molecular regulation of eNOS/SIRT1-related endothelial dysfunction and its contribution to CVD pathologies; furthermore, we selected nine different miRNAs that target the expression of eNOS and SIRT1 in CVDs. Additionally, we have summarized the alteration of miRNA expression and regulation of activities of miRNA through natural antioxidant consumption.

Antioxidant effect of ethanolic onion (Allium cepa) husk extract in ageing rats.

The role of natural antioxidants in preventing of age-relating diseases is evident. The vegetable industry generates a large amount of waste, which is a good source of antioxidants.The aim of the study was the investigation of the antioxidant effect of long-term consumption of ethanolic yellow onion husk extract in ageing laboratory rodents.Twenty male Wistar albino rats were divided randomly into two groups (n = 10): a control group and an experimental group that received ethanolic yellow onion husk extract (2 mL/rat diluted with distilled water; activity of 4.44 µmol-equiv. quercetin) for 188 days. Oxygen radical absorbance capacity and ferric reducing antioxidant power assays were used to determine the total antioxidant capacity of the extract, which amounted to 941.4 ± 32.7 µmol equiv. Trolox/g raw material and 167.4 ± 16.4 µmol-equiv. quercetin/g raw material, respectively. Oral intake of the onion husk extract affected the indicators of the antioxidant system of the liver and the brain but not of the blood and plasma, mainly due to elevations in the activity of catalase and superoxide dismutase in the liver by 44.4% and 79.1%, respectively, and in the brain by three-fold and 79.1%, respectively.The availability, cheapness and high antioxidant potential of onion waste qualifies it a good source of functional ingredients and bioactive substances applicable in the food and pharmaceutical industries.

The Role of Natural Antioxidants in the Prevention of Dementia-Where Do We Stand and Future Perspectives.

Dementia, and especially Alzheimer’s disease (AD), puts significant burden on global healthcare expenditure through its increasing prevalence. Research has convincingly demonstrated the implication of oxidative stress in the pathogenesis of dementia as well as of the conditions which increase the risk of developing dementia. However, drugs which target single pathways have so far failed in providing significant neuroprotection. Natural antioxidants, due to their effects in multiple pathways through which oxidative stress leads to neurodegeneration and triggers neuroinflammation, could prove valuable weapons in our fight against dementia. Although efficient in vitro and in animal models of AD, natural antioxidants in human trials have many drawbacks related to the limited bioavailability, unknown optimal dose, or proper timing of the treatment. Nonetheless, trials evaluating several of these natural compounds are ongoing, as are attempts to modify these compounds to achieve improved bioavailability.

Natural Antioxidants Beneficial Effects on Anion Exchange through Band 3 Protein in Human Erythrocytes.

Band 3 protein (B3p) exchanging Cl− and HCO3− through erythrocyte membranes is responsible for acid balance, ion distribution and gas exchange, thus accounting for homeostasis of both erythrocytes and entire organisms. Moreover, since B3p cross links with the cytoskeleton and the proteins underlying the erythrocyte membrane, its function also impacts cell shape and deformability, essential to adaptation of erythrocyte size to capillaries for pulmonary circulation. As growing attention has been directed toward this protein in recent years, the present review was conceived to report the most recent knowledge regarding B3p, with specific regard to its anion exchange capability under in vitro oxidative conditions. Most importantly, the role of natural antioxidants, i.e., curcumin, melatonin and Mg2+, in preventing detrimental oxidant effects on B3p is considered.

Jussara berry (Euterpe edulis M.) oil-in-water emulsions are highly stable: the role of natural antioxidants in the fruit oil.

Antioxidants help prevent lipid oxidation, and therefore are critical to maintain sensory quality and chemical characteristics of edible oils. Jussara berry (Euterpe edulis M.) oil is a source of minor compounds with potential antioxidant activity. The aim of this work was to investigate the role of such compounds on the effectiveness to prevent or delay oxidation of oil present in oil-in-water emulsions, and how the emulsions' physical stability would be affected. Jussara berry oil extracted by ethanol extraction, its stripped variations (partially stripped, highly stripped and highly stripped with added butylhydroxytoluene), and expeller-pressed oil were used to prepare oil-in-water emulsions. Jussara berry oils were analyzed before emulsions preparation to ensure their initial quality and composition, and oil-in-water emulsions were analyzed regarding their oxidative and physical stability. Ethanol extracted oil emulsion presented higher oxidative stability than highly stripped oil emulsion with added synthetic antioxidant butylahydroxytoluene (oxidative stability index 45% lower, after 60 days, and reached undetectable levels after 90 days). All emulsions remained physically stable for up to 120 days of storage. Our results indicate that natural antioxidants in jussara berry oil protect emulsions from oxidation while keeping physical stability unchanged. © 2018 Society of Chemical Industry.

The Role of the MAPK Signaling, Topoisomerase and Dietary Bioactives in Controlling Cancer Incidence.

Reactive oxygen species (ROS) are common products of mitochondrial oxidative phosphorylation, xenobiotics metabolism and are generated in response to several environmental stress conditions. Some of them play important biochemical roles in cellular signal transduction and gene transcription. On the other hand, ROS are known to be involved in a wide range of human diseases, including cancer. The excessive production of such ROS together with disruption of homeostasis detoxifying mechanisms can mediate a series of cellular oxidative stresses. The oxidative stress of redundant free radicals production can lead to oxidative denaturation of cellular macromolecules including proteins, lipids and DNA. Moreover, oxidative damage is one of the major causes of DNA mutations, replication errors and genomic abnormalities which result in either inhibition or induction of transcription, and end with the disturbance of signal transduction pathways. Among affected signaling pathways are redox-sensitive kinases. The stimulation of these kinases induces several transcription factors through the phosphorylation of their module proteins. The activation of such pathways induces proliferation and cellular transformation. A diet rich in antioxidant compounds has potential health benefits, and there is a growing interest in the role of natural antioxidants in nutrition for prevention and cure of cancer diseases. A controversy has risen regarding the relation between antioxidants and the significant decrease in the risk of cancer incidence. In this review, we will focus on redox-sensitive kinases signaling pathways, highlighting the effects of dietary antioxidant on the prevention, incidence, prognosis or even treatment of human cancers. In addition, we will place emphasis on the chemical classes of pterocarpans as natural anti-oxidants/cancers as well as their underlying mechanisms of action, including their effects on MAPKs and topoisomerase activities.

Protective Effects of Green tea, Clove and Thyme against Mullet (Mugil cephalus) Lipid Hydrolysis and Oxidation: Role of Natural Antioxidants

Protective Effects of Green tea, Clove and Thyme against Mullet (Mugil cephalus) Lipid Hydrolysis and Oxidation: Role of Natural Antioxidants

Role of natural antioxidants in the therapeutic management of hepatocellular carcinoma

Hepatoma Research is an open access journal and focuses on all topics related to hepatoma. The following articles are especially welcome: pathogenesis, clinical examination and early diagnosis of hepatoma, complications of hepatoma, and their preventions and treatments, etc.

Role of Natural Antioxidants in the Modulation of Plasma Amino Acid Pattern in Rats Exposed to Hemic Hypoxia

The aim of this work was to investigate whether the free radical scavengers, L-arginine (L-arg) and/or carnosine, either alone, or in combination would modulate tissue injury induced by hypoxia by measuring Fischer's ratio [concentrations of branched chain amino acids (BCAAs)/aromatic amino acids]. Decreased Fischer's ratios and increased malondialdehyde (MDA) led to pathogeneses of many diseases. Rats were injected with sodium nitrite (60 mg/kg) to establish hypoxia. They were treated with L-arg, (200 mg/ kg) and/or carnosine (200 mg/ kg) and their combination 24 and 1 h prior to sodium nitrite intoxication. The results revealed that hypoxia significantly decreased hemoglobin, arginine, citrulline and proline and increased sLDH, MDA , ammonia , urea, BCAAs (valine, leucine and isoleucine) and aromatic amino acids (phenylalanine and tyrosine ). The Fischer's ratio was decreased compared with the control; the administration of the aforementioned antioxidants ameliorated most of the previously altered parameters. It was concluded that Fischer's ratio was a valuable tool for understanding the pathology of hemic hypoxia, evaluating the degree of the modulatory effect of various natural antioxidants and the synergy between L-arg and carnosine in ameliorating the effect of sodium nitrite on amino acids pattern. Thus, it could be recommended to administer the combination of L-arg and carnosine in the areas of high altitudes to combat the hazard effect of hypoxia on hemoglobin concentration and MDA level.

Cytoprotective effects of geraniin against peroxynitrite- and peroxyl radical-induced cell death via free radical scavenging activity

The role of natural antioxidants in combating the deleterious effects of free radicals has received much attention. In the present study, the cytoprotective effects and the free radical scavenging activity of geraniin, a hydrolysable ellagitannin from Nephelium lappaceum rind, were evaluated by using various approaches. Addition of geraniin to the culture media resulted in a profound cytoprotective effect against damages induced by the peroxynitrite generator 3-morpholinosydnonimine (SIN-1), and the peroxyl radical generator 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH). Geraniin exhibits more potent cytoprotective activity than that of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox). Geraniin exhibited potent antioxidant activity against reactive species, such as nitric oxide, superoxide anion, and chemically synthesized peroxynitrite. Kinetic analysis of reactivity against peroxyl radicals generated by AAPH revealed that geraniin possesses potent reactivity against peroxyl radicals with higher stoichiometric number than Trolox. The cytoprotective effect of geraniin was only observed when geraniin and these toxic compounds were co-existing, suggesting that geraninn exhibits cytoprotective effects via free radical scavenging activity in the extracellular fluid.

Antioxidant Research in Asia in the Period from 2000-2008

Problem statement: Plant antioxidants are natural plant products that inhibit the adverse effects of the Reactive Oxygen Species (ROS) produced in plants. Thus, antioxidants enable plants to survive. Depending on this principle, human beings started using some plants’ parts to cure from diseases many centuries ago, even before the discovery of microbes or disclosing the etiology of many human diseases. Shed light on the importance of diet and natural products that have proved of great health impact on human traditionally and scientifically, disclosing the central role of natural antioxidants in this matter. Moreover, this review tried to give an overview on the research has so far done in Asian countries particularly in the field of natural antioxidants during the period 2000-2008. Therefore, the aim of this review is to present a comprehensive index for the antioxidant property of herbs and plants that have been traditionally used as well as experimentally proved beneficial in these countries. Approach: We had compared Asian and other nation's diet in the popularity of the traditional medicine and the type of daily meal in respect to their antioxidants contents and valuable health promoting effects. Many literatures had been collected using online search engines and the main library of University Putra Malaysia. The gathered data had been arranged alphabetically in a table depending on the plant’s scientific name, common name, the used part(s) and the family name. Results: The research had shown that there were seventy-six plants with proved antioxidant activity which had been well studied by Asian scientists in the chosen period of time. Conclusion: The antioxidant components of the natural products constitute the major source of human health promotion and maintenance. The nature is still the perfect source for health promotion and for the supplementation of safe drugs. Great attention is mandatory from all the scientists around the world to explore many underestimated plants with highly effective antioxidant activity.

Antioxidant potential of synthetic and natural antioxidants and its effect on warmed-over-flavour in different species of meat

The role of natural antioxidants, e.g. Maillard reaction products (MRPs 60 mM/2 h), ascorbic acid (500 ppm), cloves ( Eugenia caryophyllata) (250 mg/100 g), cinnamon ( Cinnamomum zeylanicum) (250 mg/100 g) and synthetic antioxidants, e.g. tertiary butyl hydroxy quinone (TBHQ), butylated hydroxy anisole (BHA) and propyl gallate (PG), at 0.02% level each, in controlling the warmed-over-flavour (WOF), and non-haem iron release, as well as their potential in cooked and refrigerated stored meats from three common domestic species (sheep, beef and pork) has been investigated. MRPs and TBHQ showed good antioxidant activity (82–91%) and were significantly different ( P < 0.05) from the other treatments in all three species. Significantly ( P < 0.05) lower values of hexanal and non-haem iron were obtained for MRPs and TBHQ treated samples, which showed ability to control WOF during refrigerated storage. Non-linear correlation regression analysis was performed between non-haem iron, WOF values and antioxidant activity in all three species. Exponential fit equations were established for beef and pork, while for sheep, the relationship was found to be polynomial with correlation coefficients ranging from 0.90 to 0.97 for non-haem iron and WOF, respectively. The susceptibility of these species to lipid oxidation was in the order, pork > beef > sheep, and the order of antioxidant activity for the natural antioxidants was MRPs > cloves > ascorbic acid > cinnamon; for synthetics it was TBHQ > BHA > PG.

Free radical lipid peroxidation inhibits enzymatic conversion of beta-carotene into vitamin A.

Free radical oxidation of arachidonic acid with soybean lipoxygenase was accompanied by inhibition of retinal synthesis from beta-carotene catalyzed by enzyme preparation from rabbit intestinal mucosa. Lipoxygenase inhibitor salicylhydroxamic acid and antioxidants suppressing free radical reactions (ethyl gallate, alpha-tocopherol, astaxanthine, and quercetin) promoted conversion of beta-carotene into retinal catalyzed by beta-carotene-15,15'-dioxygenase. These results indicate that lipoperoxides and/or products of their homolysis attenuate enzymatic conversion of beta-carotene and confirm the important role of natural antioxidants in the maintenance of stable vitamin A content in mammals.

The role of natural antioxidants in preserving the biological activity of endothelium-derived nitric oxide

Endothelium-derived nitric oxide (EDNO) is a pivotal molecule in the regulation of vascular tone via the stimulation of vascular smooth muscle cell relaxation and concomitant vasodilation. In addition, EDNO exerts a number of other potent antiatherogenic effects, including inhibition of leukocyte-endothelial interactions, smooth muscle cell proliferation, and platelet aggregation. Endothelial vasodilator dysfunction has been observed in patients with CAD or coronary risk factors such as hypercholesterolemia, hyperhomocysteinemia, essential hypertension, diabetes mellitus, smoking, and aging. Most of these conditions are associated with increased oxidative stress, particularly increased production of superoxide radicals and elevated levels of oxidized LDL, both of which can attenuate the biological activity of EDNO. The levels of superoxide and oxidized LDL can be decreased by administering the small molecule antioxidants vitamins E and C. Vitamin C also spares intracellular thiols, which in turn can stabilize EDNO through the formation of biologically active S-nitrosothiols. Here we review the role that vitamins E and C and thiol compounds play in endothelium-dependent vasodilation. Understanding the mechanisms of the reversal of endothelial dysfunction by natural antioxidants will lead to successful therapeutic interventions of CAD and its clinical sequelae.

Free radicals and oxidative modification of LDL. Role of natural antioxidants

Free radicals and oxidative modification of LDL. Role of natural antioxidants