Synergy research: vitamins and secondary plant components in the maintenance of the redox-homeostasis and in cell signaling

Review and Chemoinformatic Analysis of Ferroptosis Modulators with a Focus on Natural Plant Products

Ferroptosis is a regular cell death pathway that has been proposed as a suitable therapeutic target in cancer and neurodegenerative diseases. Since its definition in 2012, a few hundred ferroptosis modulators have been reported. Based on a literature search, we collected a set of diverse ferroptosis modulators and analyzed them in terms of their structural features and physicochemical and drug-likeness properties. Ferroptosis modulators are mostly natural products or semisynthetic derivatives. In this review, we focused on the abundant subgroup of polyphenolic modulators, primarily phenylpropanoids. Many natural polyphenolic antioxidants have antiferroptotic activities acting through at least one of the following effects: ROS scavenging and/or iron chelation activities, increased GPX4 and NRF2 expression, and LOX inhibition. Some polyphenols are described as ferroptosis inducers acting through the generation of ROS, intracellular accumulation of iron (II), or the inhibition of GPX4. However, some molecules have a dual mode of action depending on the cell type (cancer versus neural cells) and the (micro)environment. The latter enables their successful use (e.g., apigenin, resveratrol, curcumin, and EGCG) in rationally designed, multifunctional nanoparticles that selectively target cancer cells through ferroptosis induction.

The Impact of Natural Antioxidants on the Regenerative Potential of Vascular Cells

With advances in technology, the impact of natural antioxidants on vascular cell regeneration is attracting enormous attention as many current studies are now exploring the clinical potential of antioxidants in regenerative medicine. Natural antioxidants are an important step for improving future treatment and prevention of various diseases such as cardiovascular, cancer, neurodegenerative, and diabetes. The use of natural antioxidants which have effects on several types of stem cells with the potential to differentiate into functional endothelium and smooth muscle cells (known as vascular progenitors) for vascular regeneration might override pharmaceutical and surgical treatments. The natural antioxidant systems comprise of several components present in fruits, vegetables, legumes, medicinal plants, and other animal-derived products that interact with reactive free radicals such as oxygen and nitrogen species to neutralize their oxidative damaging effects on vascular cells. Neutralization by antioxidants involves the breaking down of the oxidative cascade chain reactions in the cell membranes in order to fine-tune the free radical levels. The effect of natural antioxidants on vascular regeneration includes restoration or establishment of new vascular structures and functions. In this review, we highlight the significant effects of natural antioxidants on modulating vascular cells to regenerate vessels, as well as possible mechanisms of action and the potential therapeutic benefits on health. The role of antioxidants in regenerating vessels may be critical for the future of regenerative medicine in terms of the maintenance of the normal functioning of vessels and the prevention of multiple vascular diseases.

Implication of the Significance of Dietary Compatibility: Based on the Antioxidant and Anti-Inflammatory Interactions with Different Ratios of Hydrophilic and Lipophilic Antioxidants among Four Daily Agricultural Crops

The hydrophilic extracts of eggplant peel (HEEP) and purple sweet potato (HEPP) and lipophilic extracts of tomato (LET) and carrot (LEC) were mixed in different ratios to assess the significance of the compatibility of aliments, based on their antioxidant and anti-inflammatory interactions in H9c2 cells. The results indicated that groups of some combinational extracts (HEPP-HEEP F1/10, LEC-HEEP F3/10, LEC-HEPP F3/10) showed stronger synergistic antioxidant and anti-inflammatory effects than individual groups. For example, the glutathione peroxidase (GPx) activity of the LEC-HEEP (F3/10) group (86.71 ± 1.88) was higher than that in the HEEP (79.97 ± 1.68) and LEC (77.31 ± 1.85) groups. The level of reactive oxygen species (ROS) was 30.37 ± 0.25 in the LEC-HEEP (F3/10) group while the levels were 34.34 ± 0.36 and 46.23 ± 0.51 in the HEEP and LEC groups, respectively. And the level of malondialdehyde (MDA) was 1.82 ± 0.24 in the LEC-HEEP (F3/10) group while the levels were 2.48 ± 0.13 and 3.01 ± 0.24 in the HEEP and LEC groups, respectively. The expressions of inflammatory mediators (IL-1β, IL-6, IL-8) and cell adhesion molecules (VCAM-1, ICAM-1) showed similar tendencies. However, some groups (LET-LEC F5/10, LET-LEC F9/10, LET-HEPP F7/10) showed antagonistic effects based on these indicators. The principal component analysis showed that samples could be defined by two principal components: PC1, the main phenolic acids and flavonoids; PC2, carotenoids. Moreover, phenolics and anthoyanins were in the majority in synergistic groups, and carotenoids were in the majority in antagonistic groups. These results indicated that there exist synergistic or antagonistic interactions of aliments on antioxidation and anti-inflammation, which implied the significance of food compatibility.

Antioxidant and anti-inflammatory activities of freeze-dried grapefruit phenolics as affected by gum arabic and bamboo fibre addition and microwave pretreatment

BACKGROUND

Recent epidemiological studies have suggested that phenolic compounds present in grapefruit play an important role in the bioactive properties of this fruit. However, the consumption of fresh grapefruit is low. Freeze-dried powdered grapefruit can be an alternative to promote this fruit consumption. To improve the quality and stability of the powdered fruit, encapsulating and anticaking agents can be added. In the present study, different grapefruit powders obtained by freeze-drying with the addition of gum arabic (1.27 g per 100 g) and bamboo fibre (0.76 g per 100 g) with and without a pre-drying microwave treatment were compared with the fresh and freeze-dried fruit with no carriers added, aiming to evaluate the effect of these preservation processes on phenolics content and on its antioxidant [1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and ferric reducing ability of plasma (FRAP)] and anti-inflamatory (evaluated in RAW 264.7 macrophages) capacities.

RESULTS

Freeze-drying and gum arabic and bamboo fibre addition significantly increased total phenolics, as well as the antioxidant and anti-inflammatory activities (by inhibiting nitric oxide production of lipopolysaccharide activated RAW 264.7 macrophages), of grapefruit. An additional increase in these parameters was obtained with microwave pretreatment before freeze-drying.

CONCLUSIONS

The combined addition of gum arabic and bamboo fibre to grapefruit puree and the application of a microwave pretreatment improve the functional properties of the fruit without showing cytotoxicity in vitro. © 2017 Society of Chemical Industry.

Anthropometric and Dietary Factors as Predictors of DNA Damage in Obese Women

Enhanced DNA damage and disturbances in DNA repair mechanisms are reported to be involved in the pathogenesis of chronic diseases like obesity, atherosclerosis, metabolic syndrome, diabetes, and cancer. The aim of the present study was to evaluate whether anthropometric factors and dietary habits are related to endogenous DNA damage. One hundred and fourteen premenopausal, apparently healthy women were included in the study: 88 obese individuals and 26 controls. The comet assay was used to measure basal DNA damage. Biochemical measurements included lipids, apolipoproteinAI, fasting insulin, glucose, and C-reactive protein high sensitivity (CRP-hs). Dietary intakes were assessed by 3-day food records. The mean level of DNA damage was almost two times higher in obese than in non-obese women (p < 0.001). Regression modeling showed that body mass index (BMI), daily intakes of energy, and vitamin C are key predictors of variance in basal DNA damage. Our data demonstrate the impact of obesity-associated inflammation on DNA damage and indicate that regardless of obesity, the level of DNA damage can be reduced by adequate intakes of vitamins C and E. It suggests that particular attention should be paid to the content of antioxidants in the diet of obese people and further studies are needed to modify dietary guidelines to prevent DNA damage in obese individuals.

Cav-1 deficiency promotes liver fibrosis in carbon tetrachloride (CCl4)-induced mice by regulation of oxidative stress and inflammation responses

Caveolin-1 (Cav-1), as a membrane protein involved in the formation of caveolae, binds steroid receptors and endothelial nitric oxide synthase, limiting its translocation and activation. In the present study, we investigated the role of Cav-1 in the progression of hepatic fibrosis induced by carbon tetrachloride (CCl₄) in murine animals. Therefore, the wild type (WT) and Cav-1-knockout (Cav-1^-/-) mice were used in our study and subjected to CCl₄. The results indicated that CCl₄ induced the decrease of Cav-1 expression in liver tissue samples. And Cav-1^-/- intensified CCl₄-triggered hepatic injury, evidenced by the stronger hepatic histological alterations, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and liver terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells. CCl₄ led to oxidative stress, supported by the reduced superoxide dismutase (SOD) activity and glutathione (GSH) levels, as well as enhanced malondialdehyde (MDA) and O₂^- levels in liver samples. And the process was intensified by Cav-1^-/-. Additionally, CCl₄-caused hepatic inflammation was aggregated by Cav-1^-/- via further increasing the secretion of pro-inflammatory cytokines. Moreover, CCl₄-caused fibrosis was strengthened by Cav-1^-/-, which was evidenced by the up-regulation of α-smooth muscle actin (α-SMA), collagen alpha 1 type 1 (Col1A1), lysyl oxidase (Lox) and transforming growth factor-β1 (TGF-β1) in liver tissues. Similar results were observed in TGF-β1-stimulated hepatic stellate cells (HSCs) and LX-2 cells without Cav-1 expressions that in vitro, suppressing Cav-1 further accelerated TGF-β1-induced oxidative stress, inflammation and fibrosis development. In conclusion, our results indicated that Cav-1 played an important role in CCl₄-induced hepatic injury, which may be used as potential therapeutic target for hepatic fibrosis treatment.

Avaliação da ingestão de nutrientes antioxidantes pela população brasileira e sua relação com o estado nutricional

RESUMO: Introdução: O estudo dos antioxidantes dietéticos tem ganhado destaque em função da elucidação dos efeitos deletérios do estresse oxidativo ao organismo. Objetivo: Avaliar a ingestão de nutrientes antioxidantes pela população brasileira e sua relação com o estado nutricional. Métodos: Realizou-se um estudo transversal com coleta de dados secundários do consumo alimentar de 33.459 indivíduos de ambos os sexos, de 10 ou mais anos, de todas as regiões do Brasil, a partir dos microdados da Pesquisa de Orçamentos Familiares (2008 - 2009), Inquérito Nacional de Alimentação. Foram analisados os teores das vitaminas E, A e C, zinco, manganês, cobre e selênio de 188 itens alimentares, divididos em 12 grupos, conforme a forma habitual de consumo. As médias de ingestão dos nutrientes antioxidantes de acordo com o estado nutricional foram comparadas por meio do teste t de Bonferroni. Resultados: Foram observados maiores percentuais de ingestão insuficiente para as vitaminas do que para os minerais antioxidantes. Notou-se diferença significativa na ingestão da vitamina E em relação ao estado nutricional, sendo que a ingestão por indivíduos com excesso de peso foi inferior em relação aos com peso adequado. Verificou-se que os indivíduos com baixo peso apresentaram menor ingestão de quase todos os minerais antioxidantes, exceto o cobre, em que a ingestão por indivíduos com baixo peso foi igual à ingestão por aqueles com peso adequado. Conclusão: Elevados percentuais de ingestão insuficiente de nutrientes antioxidantes foram observados na população estudada, especialmente para as vitaminas. Além disso, a ingestão de nutrientes antioxidantes variou conforme o estado nutricional, o sexo e o estágio de vida.

The effect of weight reduction on antioxidant enzymes and their association with dietary intake of vitamins A, C and E

OBJECTIVE

Our goal was to assess the effects of weight loss on antioxidant enzymes of red blood cells and it's relation with vitamins A, E and C intake in 30 obese women.

SUBJECTS AND METHODS

General information, anthropometric measurements, 3-day food recall, and fasting blood samples were collected from 30 obese women at the beginning of the study and after 3 months intervention. Weight loss was set at about 10% of their weight before the intervention.

RESULTS

Glutathione reductase and catalase activities showed a significant increase (P < 0.01) after weight reduction, but no significant changes were seen in the superoxide dismutase and glutathione peroxidase activities. There was a positive linear correlation between daily vitamin C intake with superoxide dismutase enzyme after intervention (P = 0.004, r = 0.507). There was a negative linear correlation between vitamin E intake and glutathione peroxidase activity before intervention (P = 0.005, r = -0.5). A negative correlation was found between daily vitamin A intake and glutathione reductase enzyme before and after intervention (r = -0.385, r = -0.397, P < 0.05) respectively. No significant correlation was observed between vitamins A, C, E amounts and catalase activity.

CONCLUSIONS

Ten percent weight reduction can have a significant role in increasing antioxidant enzymes activities, especially glutathione reductase, and catalase enzymes in obese women. However, it is important to take into consideration a balanced amount of certain nutrients while administering a diet with limited energy.

Silymarin and hepatocellular carcinoma: a systematic, comprehensive, and critical review

The blessed milk thistle (Silybum marianum L.), a flowering plant native to Mediterranean Europe, has been consumed and extensively used as a cure for various chronic liver ailments over several centuries. Milk thistle extract, known as silymarin, is a complex mixture of seven major flavonolignans and one flavonoid. The phytoconstituents of silymarin owe their therapeutic and hepatoprotective effects to their strong antioxidant and anti-inflammatory properties. Primary liver cancer, also known as hepatocellular carcinoma (HCC), occurs in a milieu of oxidative stress and inflammation. The etiology of HCC includes chronic infection with hepatitis B and C viruses, cirrhosis, and exposure to dietary and environmental hepatocarcinogens. Current therapeutic options for HCC, including surgical resection and liver transplantation, have limited benefits and are essentially ineffective. Chemoprevention, using phytochemicals with potent antioxidant and anti-inflammatory properties, represents a fascinating strategy, which has been a subject of intense investigation in the recent years. In this review, we explore the potential role of silymarin as a chemopreventive and therapeutic agent for HCC. The review systematically evaluates the preclinical in-vitro and in-vivo studies investigating the effects of silymarin and its constituents on HCC. The biochemical mechanisms involved in the anti-liver-cancer effects of silymarin have been presented. The current status of clinical studies evaluating the potential of role of silymarin in liver cancer, especially that caused by hepatitis C virus, has also been examined. Potential challenges and future directions of research involved in the 'bench-to-bedside' transition of silymarin phytoconstituents for the chemoprevention and treatment of HCC have also been discussed.

Number of Hydroxyl Groups on the B-Ring of Flavonoids Affects Their Antioxidant Activity and Interaction with Phorbol Ester Binding Site of PKCδ C1B Domain: In Vitro and in Silico Studies

Although flavonoids have been reported for their benefits and nutraceutical potential use, the importance of their structure on their beneficial effects, especially on signal transduction mechanisms, has not been well clarified. In this study, three flavonoids, pinocembrin, naringenin, and eriodictyol, were chosen to determine the effect of hydroxyl groups on the B-ring of flavonoid structure on their antioxidant activity. In vitro assays, including DPPH scavenging activity, ROS quantification by flow cytometer, and proteins immunoblotting, and in silico analysis by molecular docking between the flavonoids and C1B domain of PKCδ phorbol ester binding site were both used to complete this study. Eriodictyol (10 μM), containing two hydroxyl groups on the B-ring, exhibited significantly higher (p < 0.05) antioxidant activity than pinocembrin and naringenin. The IC50 values of eriodictyol, naringenin, and pinocembrin were 17.4 ± 0.40, 30.2 ± 0.61, and 44.9 ± 0.57 μM, respectively. In addition, eriodictyol at 10 μM remarkably inhibited the phosphorylation of PKCδ at 63.4% compared with PMA-activated RAW264.7, whereas pinocembrin and naringenin performed inhibition activity at 76.8 and 72.6%, respectively. According to the molecular docking analysis, pinocembrin, naringenin, and eriodictyol showed -CDOCKER_energy values of 15.22, 16.95, and 21.49, respectively, reflecting that eriodictyol could bind with the binding site better than the other two flavonoids. Interestingly, eriodictyol had a remarkably different pose to bind with the kinase as a result of the two hydroxyl groups on its B-ring, which consequently contributed to greater antioxidant activity over pinocembrin and naringenin.

The Evaluation of Antioxidant Interactions among 4 Common Vegetables using Isobolographic Analysis

Isobolographic analysis was used to assess the antioxidant interactions (synergism, addition, and antagonism) of 4 common vegetables (tomato [T], carrot [C], eggplant [E], and purple potato [P]). The lipophilic (L) extracts of T and C (main carotenoids), the hydrophilic (H) extracts of E and P (main phenolics) were mixed by the certain ratios (1:9, 3:7, 1:1, 7:3, 9:1, w/w) and their antioxidant activities were investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical scavenging assays, respectively. Most of the binary mixtures (LC-HE, LC-HP, HE-HP, LT-HE, and LT-HP combinations) showed the synergistic antioxidant effects. In DPPH assay, the greatest antioxidant activity of vegetable combinations was 1:9 LT-HP (EC50 : 2.45 ± 0.13 mg/mL), followed by 9:1 HE-HP (EC50 : 3.62 ± 0.12 mg/mL) and 1:9 LC-HE (EC50 : 3.74 ± 0.47 mg/mL). In ABTS assay, the greatest antioxidant activity of vegetable combinations was 9:1 HE-HP (EC50 : 4.20 ± 0.10 mg/mL), followed by 7:3 HE-HP (EC50 : 4.41 ± 0.63 mg/mL) and 1:1 HE-HP (EC50 : 5.35 ± 0.85 mg/mL). Among these combinations, 1:1 LC-HE combination showed the highest synergistic antioxidant effects in DPPH assay (synergistic rate: 87.4%), and 7:3 LC-HE combination showed the highest synergistic antioxidant effects in ABTS assay (synergistic rate: 87.0%). The mixtures of phenolics and carotenoids with suitable ratios in vegetables effectively enhanced the synergistic antioxidant effects.

Saponins from Panax japonicus attenuate D-galactose-induced cognitive impairment through its anti-oxidative and anti-apoptotic effects in rats

OBJECTIVE

To investigate the neuroprotective effects of saponins from Panax japonicus (SPJ) on D-galactose (D-gal)-induced brain ageing, and further explore the underlying mechanisms.

METHODS

SPJ were analysed using high-pressure liquid chromatography. Male Wistar rats weighing 200 ± 20 g were randomly divided into four groups: control group (saline), D-gal-treated group (400 mg/kg, subcutaneously), D-gal + SPJ groups (50, 100 and 200 mg/kg, orally) and vitamin E group (100 mg/kg). Rats were injected corresponding drugs once daily for 8 weeks. Neuroprotective effects of SPJ were evaluated by Morris water maze, histopathological observations, biochemical assays, western blot analysis and quantitative real-time polymerase chain reaction (PCR) analysis in vivo as well as reactive oxygen species (ROS) measurement and apoptosis assay in vitro.

KEY FINDINGS

Our present study showed that D-gal had a neurotoxic effect in rats and in SH-SY5Y cells due to oxidative stress induction, including decreased total anti-oxidant capacity, superoxide dismutase (SOD) and glutathione peroxidase activity, ultimately leading to spatial learning and memory impairment in rats and ROS accumulation in SH-SY5Y cells. SPJ improved spatial learning and memory deficits, attenuated hippocampus histopathological injury and restored impaired anti-oxidative as well as anti-apoptotic capacities in D-gal-induced ageing rats. In addition, SPJ remarkably decreased lipofuscin levels, increased hippocampus nuclear factor erythroid 2-related factor 2 (Nrf2) and silent mating type information regulation 2 homologue (SIRT1) protein levels and anti-oxidant genes expression such as manganese superoxide dismutase (Mn-SOD), heme oxygenase (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1) and cysteine ligase catalytic (GCLC) in D-gal-induced brain ageing.

CONCLUSIONS

Our data suggested that D-gal induced multiple molecular and functional changes in brain similar to natural ageing process. SPJ protected brain from D-gal-induced neuronal injury through decreasing oxidative stress and apoptosis, and ultimately improving cognitive performance in D-gal-induced brain ageing. It is possibly related to Nrf2 and SIRT1-mediated anti-oxidant signalling pathways.

Oxidative stress, insulin resistance, dyslipidemia and type 2 diabetes mellitus

Oxidative stress is increased in metabolic syndrome and type 2 diabetes mellitus (T2DM) and this appears to underlie the development of cardiovascular disease, T2DM and diabetic complications. Increased oxidative stress appears to be a deleterious factor leading to insulin resistance, dyslipidemia, β-cell dysfunction, impaired glucose tolerance and ultimately leading to T2DM. Chronic oxidative stress, hyperglycemia and dyslipidemia are particularly dangerous for β-cells from lowest levels of antioxidant, have high oxidative energy requirements, decrease the gene expression of key β-cell genes and induce cell death. If β-cell functioning is impaired, it results in an under production of insulin, impairs glucose stimulated insulin secretion, fasting hyperglycemia and eventually the development of T2DM.

Oleanane triterpenoids in the prevention and therapy of breast cancer: current evidence and future perspectives

Breast cancer is one of the most frequently diagnosed cancers and major cause of death in women in the world. Emerging evidence underscores the value of dietary and non-dietary phytochemicals, including triterpenoids, in the prevention and treatment of breast cancer. Oleanolic acid, an oleanane-type pentacyclic triterpenoid, is present in a large number of dietary and medicinal plants. Oleanolic acid and its derivatives exhibit several promising pharmacological activities, including antioxidant, anti-inflammatory, hepatoprotective, cardioprotective, antipruritic, spasmolytic, antiallergic, antimicrobial and antiviral effects. Numerous studies indicate that oleanolic acid and other oleanane triterpenoids modulate multiple intracellular signaling pathways and exert chemopreventive and antitumor activities in various in vitro and in vivo model systems. A series of novel synthetic oleanane triterpenoids have been prepared by chemical modifications of oleanolic acid and some of these compounds are considered to be the most potent anti-inflammatory and anticarcinogenic triterpenoids. Accumulating studies provide extensive evidence that synthetic oleanane derivatives inhibit proliferation and induce apoptosis of various cancer cells in vitro and demonstrate cancer preventive or antitumor efficacy in animal models of blood, breast, colon, connective tissue, liver, lung, pancreas, prostate and skin cancer. This review critically examines the potential role of oleanolic acid, oleanane triterpenoids and related synthetic compounds in the chemoprevention and treatment of mammary neoplasia. Both in vitro and in vivo studies on these agents and related molecular mechanisms are presented. Several challenges and future directions of research to translate already available impressive preclinical knowledge to clinical practice of breast cancer prevention and therapy are also presented.

Protective Effects of Crocin on Ischemia-reperfusion Induced Oxidative Stress in Comparison With Vitamin E in Isolated Rat Hearts

Background:

Myocardial Injury caused by ischemia-reperfusion leads to cardiac dysfunction, tissue injury and metabolic changes. The production of reactive oxygen species (ROS) and lipid peroxidation are accompanied by ischemia-reperfusion injury.

Objectives:

The aim of this study was to assess the cardio protective potential effects of crocin in comparison with vitamin E on antioxidant capacity in ischemia-reperfusion of isolated rat hearts.

Materials and Methods:

Seventy male Sprague-Dawley rats were randomly divided into seven groups, including: sham, control and experimental groups treated with different doses of crocin (10, 20 and 40 mg/kg) or vitamin E (100 mg/kg) and a combination of crocin (40 mg/kg) with vitamin E (100 mg/kg) that were administrated orally for 21 days. The heart was quickly excised, transferred to a Langendorff apparatus at constant pressure and subjected to 30 minutes of global ischemia followed by 60 minutes of reperfusion. Cardiac damage markers and antioxidant enzymes were measured.

Results:

The results showed that superoxide dismutase and catalase enzyme activities increased and Mallon de aldehyde (MDA) decreased in animals pretreated by crocin (40 mg/kg) and vitamin E (100 mg/kg). Moreover, there was a significant improvement in post ischemic recovery of antioxidant capacity during reperfusion in rats receiving a combination of crocin (40 mg/kg) and vitamin E (100 mg/kg).

Conclusions:

The results demonstrated the protective role of crocin on antioxidant capacity, which may partially be related to stability or amplification of antioxidant systems. Like vitamin E, crocin may be beneficial for prevention or treatment of cardiac dysfunction and myocardial infarction in patients with ischemic heart disease.

Mate tea prevents oxidative stress in the blood and hippocampus of rats with acute or chronic ethanol administration

OBJECTIVE

The aim of this study was to evaluate the influence of acute and chronic intake of mate tea on the effects elicited by acute and chronic administration of ethanol.

METHODS

Oxidative stress was evaluated by measuring thiobarbituric acid-reactive substances (TBARS), as well as the activities of the antioxidant enzymes, catalase (CAT), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) in the hippocampus and blood of rats. Male Wistar rats were randomly assigned to four groups, for both acute and chronic treatment: (1) control group, (2) treated group, (3) intoxicated group, (4) and intoxicated group treated with mate tea.

RESULTS

Both ethanol administrations significantly increased TBARS in plasma and hippocampus of rats and altered antioxidant enzyme activities, changes which were reverted by mate tea administration.

CONCLUSIONS

Data indicate that acute and chronic ethanol administration induced oxidative stress in hippocampus and blood and that mate tea treatment was able to prevent this situation.

Hydrolysis influence on phytochemical composition, antioxidant activity, plasma concentration, and tissue distribution of hydroethanolic Ilex paraguariensis extract components

The infusion of aerial parts of Ilex paraguariensis is widely consumed. Its antioxidant activity suggests an important role of this plant in the treatment/prevention of oxidative stress related diseases. Plant extract active compounds are frequently found in esterified form that may be poorly absorbed. Hydrolysis of the extract is a possible approach to increase its bioavailability. The aim of this study was to perform a phytochemical analysis and evaluate in rats the plasma concentration and tissue distribution of antioxidant compounds in the hydroethanolic extract of Ilex paraguariensis, before and after enzymatic hydrolysis. Both extracts presented high antioxidant activity and phenolic content. Rats given single or repeated doses of the hydrolyzed extract showed increased plasma antioxidant activity and higher plasma levels of caffeic acid. However, no changes of endogenous antioxidants were observed. In conclusion, hydrolysis of the extract of Ilex paraguariensis is a strategy to improve its bioavailability and in vivo antioxidant activity.

Consumption of green tea or green tea products: is there an evidence for antioxidant effects from controlled interventional studies?

PURPOSE

Epidemiological data suggest that green tea (GT) consumption may protect against cardiovascular diseases (CVDs) and different types of cancer. This effect is attributed primarily to the antioxidant properties of flavanols from GT. This review provides an overview of controlled intervention studies investigating the effect of GT consumption on antioxidant effects ex vivo and in vivo.

METHODS

The Medline and Cochrane databases were searched independently by two investigators for controlled intervention studies (English) on GT consumption and antioxidant effects published up to June 2010. Thirty-one studies investigating antioxidant effects ex vivo [plasma antioxidant capacity (AC), DNA's resistance against oxidative induced damage) or in vivo (lipid and protein oxidation, DNA damage] met the criteria. Results were compared by considering the participants, the dose of GT, the amount of ingested flavanols, the duration of supplementation and the investigated biomarkers.

RESULTS

The comparison between the studies was difficult as relevant data, e.g., on flavanol concentration in plasma (10 of 31 studies) or on major antioxidants contributing to AC, were often missing. Lipid peroxidation and DNA damage were commonly investigated. Data on protein oxidation are scarce. An antioxidant effect of at least one parameter (increase in AC or reduction of oxidative stress marker) was observed in 15 out of 22 studies by daily consumption of GT, primarily in participants exposed to oxidative stress (smokers or mixed collectives of smokers and non-smokers and physical activity) and in 6 out of 9 studies investigating the bolus consumption of GT.

CONCLUSION

There is limited evidence that regular consumption of GT in amounts of at least 0.6-1.5 l/day may increase AC and reduce lipid peroxidation (especially oxidation of LDL). This may contribute to the protection against CVDs and different types of cancer. Beneficial effects seem to be more likely in participants exposed to oxidative challenge.

Antioxidant and cytotoxic properties of an aqueous extract from the Argentinean plant Hedeoma multiflorum

CONTEXT

Hedeoma multiflorum Benth. (Lamiaceae) is widely used in Argentinean popular medicine for digestive and anti-spasmodic purposes. However, knowledge about its pharmacological properties has been poorly investigated.

OBJECTIVE

The antioxidant and cytotoxic properties of an aqueous extract from the plant were investigated for the first time.

MATERIAL AND METHODS

Scavenging of stable free radicals of 2,2-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS(+)) and 2,2-diphenyl-1-picryl hydrazyl (DPPH), reducing of ferric (III) iron of ferric reducing ability of plasma (FRAP) reagent, and inhibition of lipid peroxidation (LP) of human plasma and rat brain homogenates were assessed. Cytotoxicity was tested on human polymorphonuclear (PMN) cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cytotoxicity was assessed by flow cytometric techniques.

RESULTS

Extract scavenged ABTS(+) and DPPH (1.78 and 0.78 µmol Trolox equivalent/mg dry extract, respectively) and reduced FRAP reagent (0.66 µmol ascorbic acid equivalent/mg dry extract). LP of human plasma and rat brain was also inhibited in a dose-dependent way (inhibitory concentration 50%=27.0 and 86.0 µg/mL, respectively). Extract is rich in polyphenol compounds (0.96 ± 0.08 µmol equivalent caffeic acid/mg dry matter). Treatment of PMN decreased significantly the cell ability to reduce the MTT salt and increased the hypodiploid nuclei from 4 to 18% quantified using propidium iodide (PI). In the annexin V-Fluorescein isothiocyanate (annexin V-FITC) assay, 26% of treated cells were annexin V-FITC positive and PI negative. Using the 3,3'-dihexyloxacarbocyanine iodide uptake method, the negative fraction of cells was calculated as 29%.

DISCUSSION AND CONCLUSION

H. multiflorum extract was found to have a significant antioxidant and pro-apoptotic activities, and a great potential as a source of healthy products.

Naringenin more effectively inhibits inducible nitric oxide synthase and cyclooxygenase-2 expression in macrophages than in microglia

Macrophages and microglia are thought to account for initial disease progression in acute myocardial infarction and acute ischemic stroke. Before our study, the inhibitory effects of naringenin, a flavonoid, on lipopolysaccharide (LPS)-induced inflammation in macrophages and microglia have not been fully reported and compared. We hypothesized that naringenin can effectively inhibit LPS-induced inflammation of macrophages and microglia at different concentrations, the range of which is broader, with the lowest concentration more easily achieved in macrophages. In this study, we compared the anti-inflammatory effects of naringenin on LPS-stimulated RAW 274.6 macrophages and BV2 microglia and the suppression effects of naringenin and vitamin C (a well-known anti-inflammatory agent) on LPS-induced nitrite production. The results show that macrophages could maintain cell viability at higher naringenin concentrations and were more easily activated by LPS in comparison to microglia (200 vs 100 μmol/L; 0.1 vs 1 μg/mL). Under LPS (1 μg/mL) stimulation in both cell types, naringenin (up to 200 μmol/L in macrophages and 100 μmol/L in microglia) inhibited nitrite production and inducible nitric oxide synthase and cyclooxygenase-2 expression in a dose-dependent manner. The range of naringenin concentrations for inhibition was broader, and the lowest concentration was more easily achieved in macrophages; the lowest effective concentrations of naringenin to achieve constant suppression effect were 50 μmol/L in macrophages and 100 μmol/L in microglia, respectively. Vitamin C (100 μmol/L), compared with naringenin (100 μmol/L), had less and no suppression effect on LPS (1 μg/mL)-induced nitrite production in macrophages and microglia, respectively. In conclusion, naringenin more effectively inhibits the LPS-induced inflammatory status, including nitrite production and inducible nitric oxide synthase and cyclooxygenase-2 expression, in macrophages than in microglia. The findings of the present study suggest that consumption of naringenin-containing flavonoids might be beneficial to the cardiovascular and cerebrovascular inflammatory process.

Continuous administration of polyphenols from aqueous rooibos (Aspalathus linearis) extract ameliorates dietary-induced metabolic disturbances in hyperlipidemic mice

The incidence of obesity and related metabolic diseases is increasing globally. Current medical treatments often fail to halt the progress of such disturbances, and plant-derived polyphenols are increasingly being investigated as a possible way to provide safe and effective complementary therapy. Rooibos (Aspalathus linearis) is a rich source of polyphenols without caloric and/or stimulant components. We have tentatively characterized 25 phenolic compounds in rooibos extract and studied the effects of continuous aqueous rooibos extract consumption in mice. The effects of this extract, which contained 25% w/w of total polyphenol content, were negligible in animals with no metabolic disturbance but were significant in hyperlipemic mice, especially in those in which energy intake was increased via a Western-type diet that increased the risk of developing metabolic complications. In these mice, we found hypolipemiant activity when given rooibos extract, with significant reductions in serum cholesterol, triglyceride and free fatty acid concentrations. Additionally, we found changes in adipocyte size and number as well as complete prevention of dietary-induced hepatic steatosis. These effects were not related to changes in insulin resistance. Among other possible mechanisms, we present data indicating that the activation of AMP-activated protein kinase (AMPK) and the resulting regulation of cellular energy homeostasis may play a significant role in these effects of rooibos extract. Our findings suggest that adding polyphenols to the daily diet is likely to help in the overall management of metabolic diseases.

Novel chemotherapeutic and renal protective effects for the green tea (EGCG): role of oxidative stress and inflammatory-cytokine signaling

BACKGROUND

The green tea catechin, epigallocatechin-gallate (EGCG) is a superb nature's medicine candidate. We evaluated the chemotherapeutic/chemoenhancing effects of EGCG in mice bearing the solid Ehrlich ascites carcinoma (EAC) tumor, and jointly monitored levels of serum C-reactive protein (CRP), lipid peroxidation (as malondialdehyde: MDA) and leukocytosis (LC). Besides, we verified whether; and how then, EGCG would protect against a devastating CP-induced nephrotoxicity in rats. In particular, renal proinflammatory (TNF-α) and oxidant stress signals have been investigated.

RESULTS

(EAC)-bearing mice displayed elevated serum-LC (2-fold), -CRP (11-fold) and -MDA levels (2.7-fold). EGCG (20, 40 mg/kg) significantly shrank tumors (by 48% and 92%, respectively), and reduced LC, CRP and MDA levels. Such responses for CP were less prominent than those of EGCG (40 mg/kg). Further, EGCG (20 mg/kg) markedly augmented such functional and biochemical responses to CP. Correlation studies showed positive association between tumor size and each of CRP (r=0.97) and LC (r=0.83). Additionally; in rats, CP (10 mg/kg) caused a prominent nephrotoxicity that was manifested as deteriorated glomerular filtration rate (GFR, 2-5-fold rise in serum creatinine/urea levels) after 4 days, and unanimous animal fatalities after 7 days. Kidney homogenates from CP-treated rats showed significantly higher MDA- and TNF-α-, and -depleted GSH levels. Rats treated with EGCG (50 mg/kg, but not 25 mg/kg) devoid the nephrotoxic effects of CP and their consequences; while their homogenates had appreciably lower MDA and TNF-α, and higher GSH levels. Notable correlation was detected between serum creatinine level and each of MDA (r=0.85), TNF-α (r=0.85) and GSH (r=-0.81).

CONCLUSION

This study shows remarkable cytotoxic/chemoenhancing effects for EGCG and introduces CRP as a predictor of both tumor's progression and responsiveness to chemotherapy. Further, this study is the first to reveal that EGCG can obliterate the lethal CP-induced nephrotoxicity. Mechanistically, EGCG acts by suppressing leukocytosis, systemic inflammation, oxidative stress, and their sequelae.

Grape seed extract ameliorates tumor necrosis factor-α-induced inflammatory status of human umbilical vein endothelial cells

BACKGROUND

Inflammation has played a key role in the causation of atherosclerosis. However, the effects of grape seed extract (GSE) on the pro-inflammatory intracellular signaling, enzyme activity, and inflammatory mediators of endothelial cells have not been sufficiently studied, and less information exists on the comparison between GSE and vitamin C, a well-known antioxidant compound, on their anti-inflammatory properties.

PURPOSE

We investigated the effects of GSE and vitamin C on the cell viability, oxidative stress, monocyte adhesion, the expression of nuclear factor-κB inhibitor (IκB), intercellular adhesion molecule-1 (ICAM-1) and cyclooxygenase-2 (COX-2), and the production of prostaglandin E(2) (PG E(2)) in TNF-α-treated human umbilical vein endothelial cells (HUVECs).

METHODS

Cell viability was measured by MTT assay. The adhesion of THP-1 to HUVECs was evaluated by cell adhesion assay. The oxidized nucleoside 8-hydroxydeoxyguanosine (8-OHdG) (an indicator of oxidative damage to DNA), ICAM-1, and PG E(2) were measured by ELISA. IκB and COX-2 expression were evaluated by western blot analysis.

RESULTS

TNF-α (10, 20, and 50 ng/mL), GSE (50 and 200 μg/mL), or vitamin C (100 μM) did not affect cell viability. GSE (50-100 μg/mL) attenuated TNF-α (20 ng/mL)-induced 8-OHdG production, THP-1 adhesion, the expression of IκB degradation, ICAM-1 and COX-2, and the production of PGE(2) in a dose-dependent manner. Vitamin C (100 μM) also showed significant antioxidative and anti-inflammatory effects.

CONCLUSIONS

GSE effectively ameliorates TNF-α-induced inflammatory status of HUVECs. The findings of the present study suggest that consumption of GSE may be beneficial to inflammatory atherosclerosis.

Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples

Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.

Preventive effect of crocin of Crocus sativus on hemodynamic, biochemical, histopathological and ultrastuctural alterations in isoproterenol-induced cardiotoxicity in rats

We investigated the effects of crocin, a pharmacologically active constituent of Crocus sativus L., in isoproterenol (ISO)-induced cardiotoxicity with reference to hemodynamic, antioxidant, histopathological and ultrastructural parameters. Rats were administered crocin (5, 10 and 20mg/kg/day) or vehicle orally for 21 days along with ISO (85mg/kg, subcutaneously, at 24h interval) on 20th and 21st day. On 22nd day ISO-control rats showed cardiac dysfunction as indicated by lowering of systolic, diastolic and mean arterial blood pressures. In addition, a significant decrease in maximum positive and negative rate of developed left ventricular pressure (+/-LVdp/dt(max)) and an increase in left ventricular end-diastolic pressure (LVEDP) were observed. Furthermore, a marked reduction in the activities of myocardial creatine kinase-MB (CK-MB) isoenzyme, lactate dehydrogenase (LDH), superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) levels along with an increase in content of malondialdehyde (MDA) were observed. Myocardial necrosis, edema and inflammation were evident from the light microscopic and ultrastructural changes. Crocin at the dose of 20mg/kg/day significantly modulated hemodynamic and antioxidant derangements. The preventive role of crocin on ISO-induced MI was reconfirmed by histopathological and ultrastructural examinations. The effect at the dose of 20mg/kg/day of crocin was more pronounced than that of other two doses (5 and 10mg/kg/day). The results suggest that crocin may have cardioprotective effect in ISO-induced cardiac toxicity through modulation of oxidative stress in such a way that maintains the redox status of the cell.

Effects of total glucosides of paeony on oxidative stress in the kidney from diabetic rats

TGP, extracted from the traditional Chinese herb root of Paeonia lactiflora pall, has been shown to have therapeutic effect in experimental diabetic nephropathy. However, its mechanism is not fully understood. In this study, the effects of TGP on oxidative stress were investigated in the kidney of diabetic rats induced by streptozotocin. TGP (50, 100, 200mg/kg) was orally administered once a day for 8 weeks. TGP treatment in all three doses significantly lowered 24 h urinary albumin excretion rate in diabetic rats and attenuated glomerular volume. TGP treatment with 100 and 200mg/kg significantly reduced indices for tubulointerstitial injury in diabetic rats. The level of MDA was significantly increased in the kidney of diabetic rats and attenuated by TGP treatment at the dose of 200mg/kg. TGP treatment in a dose-dependent manner decreased the level of 3-NT protein of the kidney which increased under diabetes. T-AOC was significantly reduced in diabetic rat kidney and remarkably increased by TGP treatment at the dose of 100 and 200mg/kg. Activity of antioxidant enzyme such as SOD, CAT was markedly elevated by TGP treatment with 200mg/kg. Western blot analysis showed that p-p38 MAPK and NF-kappaB p65 protein expression increased in diabetic rat kidney, which were significantly decreased by TGP treatment. It seems likely that oxidative stress is increased in the diabetic rat kidneys, while TGP can prevent diabetes-associated renal damage against oxidative stress.

New perspectives for synergy research with the "omic"-technologies

Synergistic effects, understood as true overadditive effects, are often observed in experimental and clinical studies using phytopharmaceuticals. The introduction of the "omic"-technologies is now opening new perspectives in rationalizing these effects and making use of them in the development of a new generation of phytopharmaceuticals. This review describes possible mechanism of synergistic actions of herbal drugs by mono- and multitargeting and by the activation of signal cascades. It examines the possibilities of the standardization of single and multi component plant extracts and the prediction and assessment of the toxicity and safety of plant extracts with the support of the "omic"-technologies. It further discusses the use of phytopharmaceuticals in the context of an "individualized medicine". It makes proposals how to use the "omic"-technologies to rationalize and develop combination therapies of phytopharmaceuticals and synthetic drugs to minimize adverse reactions (ARs) or improve the therapeutic efficacy. Examples of clinical studies are given which explore already the potential of such co-medications. Modern medical therapy has acknowledged for quite some time the usefulness of combination therapies in the treatment of multifactorial diseases like cancer, cardiovascular or rheumatic diseases. The term "synergy" is rarely used in this context, the combinatory mechanisms of actions seldom completely understood and the potentially occurring adverse reactions feared. A systematic exploitation of synergy effects of phytomedical interventions alone or in combination with synthetic drugs should lead in a long term perspective to the discovery and development of more rational evidence-based interventions in the prevention and therapy of multifactorial diseases and should thereby enrich modern pharmacotherapy.