Dietary oxidative stress and antioxidant defense with an emphasis on plant extract administration

Beneficial role of virgin coconut oil supplementation against acute methotrexate chemotherapy-induced oxidative toxicity and inflammation in rats

Background

Methotrexate (MTX) is a commonly used antineoplastic and anti-rheumatoid agent whose efficacy is limited by marked organ toxicities associated with oxidative stress. The study investigated beneficial effect of virgin coconut oil (VCO) supplementation on MTX-induced oxidative stress and inflammation in rats.

Methods

Rats were divided into 4 groups (n = 6): Control, MTX (20 mg/kg bw), VCO (5%) + MTX and VCO (15%) + MTX. The pre-treatment with VCO for 14 days was followed by single intraperitoneal injection of MTX and the rats were sacrificed after 3 days. Serum activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and levels of reduced glutathione (GSH) and malondialdehyde (MDA) were determined. Interleukin-6 (IL-6), C-reactive protein (CRP) and nitric oxide (NO) levels were also evaluated.

Results

MTX induced a distinct diminution in serum activities of oxidative stress markers (SOD, CAT, GPx and GSH), while lipid peroxidation considerably increased demonstrated by MDA level. Similarly, levels of IL-6, CRP and NO increased prominently in MTX control rats. The VCO supplementation markedly enhanced resistance to the MTX-induced biochemical alterations in rats.

Conclusion

VCO can be a useful adjuvant natural product in MTX chemotherapy by reducing oxidative stress and pro-inflammatory responses.

Oxidative stress in female cancers

Breast, cervical and ovarian cancers are highly prevalent in women worldwide. Environmental, hormonal and viral-related factors are especially relevant in the development of these tumors. These factors are strongly related to oxidative stress (OS) through the generation of reactive oxygen species (ROS). The OS is caused by an imbalance in the redox status of the organism and is literally defined as "an imbalance between ROS generation and its detoxification by biological system leading to impairment of damage repair by cell/tissue". The multistep progression of cancer suggests that OS is involved in cancer initiation, promotion and progression. In this review, we described the role of OS and the interplay with environmental, host and viral factors related to breast, cervical and ovarian cancers initiation, promotion and progression. In addition, the role of the natural antioxidant compound curcumin and other compounds for breast, cervical and ovarian cancers prevention/treatment is discussed.

Six months exposure to a real life mixture of 13 chemicals' below individual NOAELs induced non monotonic sex-dependent biochemical and redox status changes in rats

This study assessed the potential adverse health effects of long-term low-dose exposure to chemical mixtures simulating complex real-life human exposures. Four groups of Sprague Dawley rats were administered mixtures containing carbaryl, dimethoate, glyphosate, methomyl, methyl parathion, triadimefon, aspartame, sodium benzoate, calcium disodium ethylene diamine tetra-acetate, ethylparaben, butylparaben, bisphenol A, and acacia gum at doses of 0, 0.25, 1 or 5 times the respective Toxicological Reference Values (TRV): acceptable daily intake (ADI) or tolerable daily intake (TDI) in a 24 weeks toxicity study. Body weight gain, feed and water consumption were evaluated weekly. At 24 weeks blood was collected and biochemistry parameters and redox status markers were assessed. Adverse effects were observed on body weight gain and in hepatotoxic parameters such as the total bilirubin, alanine aminotransferase (ALT) and alkaline phosphatase (ALP), especially in low dose and affecting mainly male rats. The low dose group showed increased catalase activity both in females and males, whereas the high dose group exhibited decreased protein carbonyl and total antioxidant capacity (TAC) levels in both sex groups. Non-monotonic effects and adaptive responses on liver function tests and redox status, leading to non-linear dose-responses curves, are probably produced by modulation of different mechanisms.

Administration of exercise-conditioned plasma alters muscle catalase kinetics in rat: An argument for in vivo-like Km instead of in vitro-like Vmax

Maximal velocity (V_max) is a well established biomarker for the assessment of tissue redox status. There is scarce evidence, though, that it does not probably reflect sufficiently in vivo tissue redox profile. Instead, the Michaelis constant (K_m) could more adequately image tissue oxidative stress and, thus, be a more physiologically relevant redox biomarker. Therefore, the aim of the present study was to side-by-side compare V_max and K_m of an antioxidant enzyme after implementing an in vivo set up that induces alterations in tissue redox status. Forty rats were divided into two groups including rats injected with blood plasma originating from rats that had previously swam until exhaustion and rats injected with blood plasma originating from sedentary rats. Tail-vein injections were performed daily for 21 days. Catalase V_max and K_m measured in gastrocnemius muscle were increased after administration of the exercise-conditioned plasma, denoting enhancement of the enzyme activity but impairment of its affinity for the substrate, respectively. These alterations are potential adaptations stimulated by the administered plasma pointing out that blood is an active fluid capable of regulating tissue homeostasis. Our findings suggest that K_m adequately reflects in vivo modifications of skeletal muscle catalase and seems to surpass V_max regarding its physiological relevance and biological interpretation. In conclusion, K_m can be regarded as an in vivo-like biomarker that satisfactorily images the intracellular environment, as compared to V_max that could be aptly parallelized with a biomarker that describes tissue oxidative stress in an in vitro manner.

Biological activity and chemical profile of Lavatera thuringiaca L. extracts obtained by different extraction approaches

BACKGROUND

Lavatera thuringiaca L. is herbaceous perennial plant from Malvaceae family, which is known for its biological activity and richness in polyphenolic compounds. Despite this, the information regarding the biological activity and chemical profile is still insufficient.

PURPOSE

Aim of this study was to investigate biological potential and chemical profile of Lavatera thuringiaca L., as well as influence of applied extraction technique on them.

STUDY DESIGN AND METHODS

Two conventional and four non-conventional extraction techniques were applied in order to obtain extracts rich in bioactive compound. Extracts were further tested for total phenolics, flavonoids, condensed tannins, gallotannins and anthocyanins contents using spectrophotometric assays. Polyphenolic profile was established using HPLC-DAD analysis. Biological activity was investigated regarding antioxidant, cytotoxic and antibacterial activities. Four antioxidant assays were applied as well as three different cell lines for cytotoxic and fifteen bacterial strain for antibacterial activity.

RESULTS AND CONCLUSION

Results showed that subcritical water extraction (SCW) dominated over the other extraction techniques, where SCW extract exhibited the highest biological activity. Study indicates that plant Lavatera thuringiaca L. may be used as a potential source of biologically compounds.

Lesion complexity drives age related cancer susceptibility in human mammary epithelial cells

Exposures to various DNA damaging agents can deregulate a wide array of critical mechanisms that maintain genome integrity. It is unclear how these processes are impacted by one's age at the time of exposure and the complexity of the DNA lesion. To clarify this, we employed radiation as a tool to generate simple and complex lesions in normal primary human mammary epithelial cells derived from women of various ages. We hypothesized that genomic instability in the progeny of older cells exposed to complex damages will be exacerbated by age-associated deterioration in function and accentuate age-related cancer predisposition. Centrosome aberrations and changes in stem cell numbers were examined to assess cancer susceptibility. Our data show that the frequency of centrosome aberrations proportionately increases with age following complex damage causing exposures. However, a dose-dependent increase in stem cell numbers was independent of both age and the nature of the insult. Phospho-protein signatures provide mechanistic clues to signaling networks implicated in these effects. Together these studies suggest that complex damage can threaten the genome stability of the stem cell population in older people. Propagation of this instability is subject to influence by the microenvironment and will ultimately define cancer risk in the older population.

Caveolin-1: An Oxidative Stress-Related Target for Cancer Prevention

Aberrant oxidative metabolism is one of the hallmarks of cancer. Reactive species overproduction could promote carcinogenesis via inducing genetic mutations and activating oncogenic pathways, and thus, antioxidant therapy was considered as an important strategy for cancer prevention and treatment. Caveolin-1 (Cav-1), a constituent protein of caveolae, has been shown to mediate tumorigenesis and progression through oxidative stress modulation recently. Reactive species could modulate the expression, degradation, posttranslational modifications, and membrane trafficking of Cav-1, while Cav-1-targeted treatments could scavenge the reactive species. More importantly, emerging evidences have indicated that multiple antioxidants could exert antitumor activities in cancer cells and protective activities in normal cells by modulating the Cav-1 pathway. Altogether, these findings indicate that Cav-1 may be a promising oxidative stress-related target for cancer antioxidant prevention. Elucidating the underlying interaction mechanisms between oxidative stress and Cav-1 is helpful for enhancing the preventive effects of antioxidants on cancer, for improving clinical outcomes of antioxidant-related therapeutics in cancer patients, and for developing Cav-1 targeted drugs. Herein, we summarize the available evidence of the roles of Cav-1 and oxidative stress in tumorigenesis and development and shed novel light on designing strategies for cancer prevention or treatment by utilizing the interaction mode between Cav-1 and oxidative stress.

Oxidation of human serum albumin exhibits inter-individual variability after an ultra-marathon mountain race

The aim of this study was to examine the oxidation of human serum albumin (HSA) caused by oxidative stress following exhaustive and demanding exercise, such as an ultra-marathon race. For this purpose, blood samples from 12 adult runners who underwent a 103 km mountain ultra-marathon race were collected before the race, and also at 24, 48 and 72 h post-race. HSA was partially purified using affinity chromatography and consequently subjected to western blot analysis in order to determine the levels of disulfide dimers indicating oxidation. For reasons of comparison, the results were correlated with those from a previous study, in which the same samples were analyzed using different oxidative stress markers. The results revealed a good correlation between albumin dimers and protein carbonyls at all time points, while there was also a significant correlation with static oxidation reduction potential at 24 h, and a negative correlation with capacity oxidation reduction potential at 24 and 48 h. In addition, an individual analysis of albumin dimers exhibited great inter-individual differences, indicating the variation of HSA oxidation between different athletes. Namely, in some athletes, HSA seemed to be the main oxidation target of serum proteins, while in other athletes, there was even a reduction of HSA. This inter-individual variability in the oxidation of HSA may suggest that different interventions (e.g., through diet) may be required in order to confront the effects on athletes following strenuous exercise. On the whole, this study suggests the importance of the assessment of albumin dimers as a predictive marker for exercise-induced oxidative stress.

The antidiabetic compound 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione, isolated from Averrhoa carambola L., demonstrates significant antitumor potential against human breast cancer cells

2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) is a cyclohexanedione found in the roots of Averrhoa carambola L., commonly known as starfruit. Researchers have shown that DMDD has significant therapeutic potential for the treatment of diabetes; however, the effects of DMDD on human cancers have never been reported. We investigated the cytotoxic effects of DMDD against human breast, lung and bone cancer cells in vitro and further examined the molecular mechanisms of DMDD-induced apoptosis in human breast cancer cells. DMDD suppressed the growth of breast carcinoma cells, but not normal mammary epithelial cells, via induction of G1 phase cell cycle arrest, oxidative stress and apoptosis. DMDD increased the level of intracellular reactive oxygen species (ROS) and DMDD-induced ROS generation was found to be associated with the mitochondrial activity. The cytotoxicity that was induced by DMDD was attenuated by co-treatment with the antioxidant N-acetyl-L-cysteine (NAC). DMDD-induced cell apoptosis involved the activation of both the intrinsic mitochondrial pathway and the extrinsic receptor pathway. In addition, DMDD inhibited the canonical NF-κB signaling pathway at all steps, including TNF-α production, phosphorylation of NF-κB p65 and IκBα, as well as TNF-α activated NF-κB p65 nuclear translocation. Collectively, our studies indicate that DMDD has significant potential as a safe and efficient therapeutic agent for the treatment of breast cancer.

Impacto da suplementação de vitamina C sobre níveis de peroxidação lipídica e glutationa reduzida em tecido hepático de camundongos com imunossupressão induzida por ciclofosfamida

RESUMO Objetivo: Investigar os efeitos da vitamina C sobre níveis de peroxidação lipídica e glutationa reduzida em tecido hepático de camundongos imunossuprimidos por ciclofosfamida. Métodos: O estudo foi realizado em camundongos Swiss, fêmeas, com 45 dias de idade, separados em quatro grupos com oito animais cada. Grupos: controle (água destilada), vitamina C (50 mg/kg), ciclofosfamida (100 + 150 mg/kg) e tratamento (vitamina C 50 mg/kg + ciclofosfamida 100 +150 mg/kg). Todas as aplicações foram via intraperitoneal. O ensaio biológico teve duração de seis dias, sendo o sétimo a eutanásia dos animais. As análises bioquímicas de peroxidação lipídica (quantificação de substâncias reativas ao ácido tiobarbitúrico) e glutationa reduzida (estimativa de tiois não proteicos) foram realizadas em tecido hepático. Resultados: A ciclofosfamida causou aumento significativo (p<0,0001) nos níveis de peroxidação lipídica. Não foram observadas alterações significativas nos grupos tratados com vitamina C. A ciclofosfamida por si só, não alterou níveis de glutationa reduzida. A vitamina C causou a redução do nível de glutationa reduzida em relação ao controle tanto nos animais que receberam ciclofosfamida quanto nos que não receberam. No entanto, nos grupos tratados com o quimioterápico houve uma interação entre a droga e a vitamina, ou seja, o quimioterápico intensificou a diminuição da glutationa reduzida provocada pela vitamina C. Conclusão: A ciclofosfamida, na dose e período utilizados, foi capaz de induzir o dano oxidativo verificado pelo aumento da peroxidação lipídica. A vitamina C, na dose de 50 mg/kg de peso, não apresentou potencial para proteger contra o dano oxidativo provocado pelo quimioterápico.

Amelioration of Benzo[a]pyrene-induced oxidative stress and pulmonary toxicity by Naringenin in Wistar rats: A plausible role of COX-2 and NF-κB

Naringenin is a naturally occurring flavanones and has been found to exhibit free radical scavenging, enzyme inhibition, antioxidants, anti-inflammatory, and anticancer activities. Present study was designed to evaluate the protective role of naringenin against benzo[a]pyrene (B[a]P)-induced oxidative stress and pulmonary toxicity. Rats were treated with naringenin at a dose of 100 mg/kg body weight (b. wt.), by oral gavage. B[a]P in a single dose of 50 mg/kg b. wt. was given intraperitoneally. Total protein, total cell counts, lactate dehydrogenase, lipid peroxidation, reduced glutathione, antioxidant enzymes activities, lung histology and expression of nuclear factor kappa B (NF-κB), and cyclo-oxygenase-2 (COX-2) was assessed to evaluate protective effects of naringenin. Histopathological and immunohistochemical studies were also carried out to observe lung toxicity and inflammation. B[a]P administration enhanced the levels of lung injury markers and reduced antioxidant enzymes activities. Naringenin treatment attenuated the levels of oxidative stress by restoring antioxidant enzymes, further improved lung histological damage and significant decrease in inflammatory responses. Naringenin also effectively decreased the expression of NF-κB, and COX-2 induced by B[a]P. These findings suggest that naringenin supplementation is beneficial in maintaining the integrity of alveoli and the epithelium that may be used as a protective agent in B[a]P-induced oxidative stress and lung damage. However, further studies are warranted to elucidate the potential mechanism of action of naringenin.

Dietary arginine and N-carbamylglutamate supplementation enhances the antioxidant statuses of the liver and plasma against oxidative stress in rats

N-Carbamylglutamate (NCG), an effective precursor of arginine (ARG), can enhance ARG synthesis, increase intestinal growth, and improve reproductive performance. However, the antioxidant effect of NCG remains largely unknown. This study aims to survey the effects of ARG and NCG supplementation on the antioxidant statuses of the liver and plasma in rats under oxidative stress. Rats were fed for 30 days with one of the three iso-nitrogenous diets: basal diet (BD), BD plus 1% ARG, and BD plus 0.1% NCG. On day 28, half of the rats fed with BD were intraperitoneally injected with 12 mg per kg body weight of diquat (diquat group) and the other half was injected intraperitoneally with sterile 0.9% NaCl solution (control group). The other diet groups also received an intraperitoneal injection of 12 mg per kg body weight of diquat, as follows: diquat + 1% ARG (DT + ARG), and diquat + 0.1% NCG (DT + NCG). Rat liver and plasma samples obtained 48 h after diquat injection were analyzed. Results indicated that diquat significantly affected the plasma conventional biochemical components (relative to the controls), which were partially alleviated in both the DT + ARG and DT + NCG groups (P < 0.05). Diquat also significantly decreased the glutathione (GSH) content (by 30.0%), and decreased anti-superoxide anion (ASA; by 13.8%) and anti-hydroxyl radical (AHR; by 38.9%) abilities in the plasma, and also decreased catalase (CAT) activity both in the liver (by 17.5%) and plasma (by 33.4%) compared with the control group. By contrast, diquat increased the malondialdehyde (MDA) content (by 23.0%) in the plasma (P < 0.05) compared with the control group. Relative to those of the diquat group, higher CAT activity and GSH content were noted in the plasma of the DT + ARG group and in the liver of both DT + ARG and DT + NCG groups (P < 0.05). Furthermore, the DT + ARG group exhibited significantly enhanced plasma ASA activity (P < 0.05). The DT + NCG group showed significantly improved total antioxidant capacity (T-AOC) in the liver and plasma (P < 0.05). Increased GSH content and elevated ASA and AHR activities were also found, but the MDA content in the plasma was depleted (P < 0.05). Compared with the DT + ARG group, the DT + NCG group showed increased liver and plasma T-AOC, enhanced plasma AHR activity, increased liver ASA activity, and decreased plasma MDA content (P < 0.05). Overall, supplementation of 1% ARG and 0.1% NCG can partially protect the liver and plasma from oxidative stress. Furthermore, compared with 1% ARG, 0.1% NCG more effectively alleviated oxidative stress.

Arginine, N-carbamylglutamate, and glutamine exert protective effects against oxidative stress in rat intestine

The objective of the current study is to evaluate the effects of dietary supplementation with arginine (ARG), N-carbamylglutamate (NCG), and glutamine (GLN) on rat intestinal morphology and antioxidant status under oxidative stress. Rats were fed for 30 d with one of the following iso-nitrogenous diets: basal diet (BD), BD plus 1% ARG, BD plus 0.1% NCG, and BD plus 1% GLN. On day 28, half of the rats fed BD were intraperitoneally injected with 12 mg/kg body weight of diquat (DT; i.e., the DT group) and the other half was intraperitoneally injected with sterile solution (i.e., the control group). The other diet groups were intraperitoneally injected with 12 mg/kg body weight of DT (i.e., DT + 1% GLN [DT + GLN], DT + 1% ARG [DT + ARG], and DT + 0.1% NCG [DT + NCG]). Rat jejunum samples obtained at 48 h after DT injection were analyzed. Results showed that DT significantly decreased catalase (CAT) activity and glutathione (GSH) content by 58.25% and 56.57%, respectively, and elevated malondialdehyde (MDA) content and crypt depth (CD) by 19.39% and 22.13%, respectively, in the jejunum (P < 0.05, relative to the control group). Compared with the DT group, the DT + GLN group exhibited significantly improved villus height (VH), villus width (VW), villus surface area (VSA), CD and total antioxidant capacity (T-AOC) activity (P < 0.05); the DT + ARG group exhibited significantly increased the ratio of VH to CD (H:D) and T-AOC activity (P < 0.05); the DT + GLN, DT + ARG and DT + NCG groups exhibited significantly enhanced CAT activity and GSH content as well as decreased MDA content (P < 0.05). Moreover, VH, VW, VSA, CD and GSH content in the DT + GLN group were higher whereas MDA content was lower compared with the corresponding values observed in both the DT + ARG and the DT + NCG groups (P < 0.05). The H:D ratio in the DT + ARG group significantly increased compared with that in the DT + NCG and DT + GLN groups (P < 0.05). Collectively, this study suggested that dietary supplementation with 1% GLN, 0.1% NCG, and 1% ARG was effective in enhancing the antioxidant status and maintaining the morphological structure of rat jejunum under oxidative stress; of these supplements, 1% GLN exerted the greatest effects on mitigating oxidative stress.

Stachytarpheta jamaicensis (L.) Vahl: From Traditional Usage to Pharmacological Evidence

Introduction. Stachytarpheta jamaicensis (L.) Vahl belongs to the family of Verbenaceae and is commonly known as Gervao, Brazilian tea, verbena cimarrona, rooter comb, or blue porter weed. It is one of the important plants with high medicinal and nutraceutical benefits. S. jamaicensis contains various medicinal properties in traditional and folk medicinal systems, with cures for several diseases. Objective. The objective of this review paper is to collect information concerning the morphology, distribution, traditional usage, phytochemical compositions, biological activities, and safety data of S. jamaicensis. Materials and Methods. The information was obtained from literature search through electronic databases such as PubMed and Google Scholar on S. jamaicensis. Results and Conclusion. The high medicinal properties of this plant, for instance, antimicrobial and antifungal effect as the main activities, but verbascoside as the main active chemical component, make it a valuable source of the medicinal compound. This review paper summarizes all information concerning the morphology, distribution, traditional usage, phytochemical compositions, pharmacological activities, and toxicological studies of S. jamaicensis.

Involvement of Cytochrome P450 in Reactive Oxygen Species Formation and Cancer

This review examines the involvement of cytochrome P450 (CYP) enzymes in the formation of reactive oxygen species in biological systems and discusses the possible involvement of reactive oxygen species and CYP enzymes in cancer. Reactive oxygen species are formed in biological systems as byproducts of the reduction of molecular oxygen and include the superoxide radical anion (∙O2-), hydrogen peroxide (H2O2), hydroxyl radical (∙OH), hydroperoxyl radical (HOO∙), singlet oxygen ((1)O2), and peroxyl radical (ROO∙). Two endogenous sources of reactive oxygen species are the mammalian CYP-dependent microsomal electron transport system and the mitochondrial electron transport chain. CYP enzymes catalyze the oxygenation of an organic substrate and the simultaneous reduction of molecular oxygen. If the transfer of oxygen to a substrate is not tightly controlled, uncoupling occurs and leads to the formation of reactive oxygen species. Reactive oxygen species are capable of causing oxidative damage to cellular membranes and macromolecules that can lead to the development of human diseases such as cancer. In normal cells, intracellular levels of reactive oxygen species are maintained in balance with intracellular biochemical antioxidants to prevent cellular damage. Oxidative stress occurs when this critical balance is disrupted. Topics covered in this review include the role of reactive oxygen species in intracellular cell signaling and the relationship between CYP enzymes and cancer. Outlines of CYP expression in neoplastic tissues, CYP enzyme polymorphism and cancer risk, CYP enzymes in cancer therapy and the metabolic activation of chemical procarcinogens by CYP enzymes are also provided.

Aging and radiation: bad companions

Aging involves a deterioration of cell functions and changes that may predispose the cell to undergo an oncogenic transformation. The carcinogenic risks following radiation exposure rise with age among adults. Increasing inflammatory response, loss of oxidant/antioxidant equilibrium, ongoing telomere attrition, decline in the DNA damage response efficiency, and deleterious nuclear organization are age-related cellular changes that trigger a serious threat to genomic integrity. In this review, we discuss the mechanistic interplay between all these factors, providing an integrated view of how they contribute to the observed age-related increase in radiation sensitivity. As life expectancy increases and so it does the medical intervention, it is important to highlight the benefits of radiation protection in the elderly. Thus, a deep understanding of the mechanistic processes confining the threat of aging-related radiosensitivity is currently of foremost relevance.

Understanding cancer and the anticancer activities of naphthoquinones – a review

Naphthoquinone moieties are present in drugs such as doxorubicin which are used clinically to treat solid cancers.

Reactive oxygen species modulator 1 (Romo1) overexpression is an independent predictor of poor survival in NSCLC patients who undergo surgical resection

OBJECTIVES

Reactive oxygen species modulator 1 (Romo1) is a novel protein that plays an important role in intracellular reactive oxygen species generation. Romo1 is overexpressed in most cancer cell lines and related to invasiveness and chemoresistance in vitro. However, little information is available on its clinical implications. We investigated the association between Romo1 expression and the clinical outcomes of non-small cell lung cancer (NSCLC) patients who underwent surgical resection.

MATERIALS AND METHODS

Romo1 protein expressions were evaluated immunohistochemically in resected tumor specimens. Survival analyses for overall population (n=110) and early-stage patients (n=97) were performed according to clinical parameters including level of Romo1 expression.

RESULTS

Multivariate analyses showed that high Romo1 expression in tumor tissues was significantly associated with short disease-free survival (hazard ratio [HR]=3.16, 95% confidence interval [CI]: 1.21-8.22), and with short overall survival (HR=3.22, 95% CI: 1.02-10.21). Stronger associations were observed between Romo1 expression and disease-free survival (HR=3.69, 95% CI: 1.39-9.97) and overall survival (HR=4.21, 95% CI: 1.12-14.67) in stage I and II patients than in the overall population. Romo1 expression was not associated with any clinical parameter including age, gender, smoking status, stage, differentiation, or tumor histology.

CONCLUSIONS

Increased Romo1 expression in surgically resected NSCLC was found to be significantly associated with early recurrence and poor survival. Romo1 overexpression could be a potential adverse prognostic marker in this setting.

Protective effect of coconut water concentrate and its active component shikimic acid against hydroperoxide mediated oxidative stress through suppression of NF-κB and activation of Nrf2 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Conventionally coconut water has been used as an 'excellent hydrating' drink that maintain the electrolyte balance and help in treating diverse ailments related to oxidative stress including liver function. The present study was aimed to elucidate whether and how the coconut water concentrate (CWC) and its major active phytoconstituent shikimic acid (SA) can effectively protect murine hepatocytes from the deleterious effect of hydroperoxide-mediated oxidative stress.

MATERIALS AND METHODS

Bioactivity guided fractionation of CWC resulted in the isolation of a couple of known compounds. Freshly isolated murine hepatocytes were exposed to hydrogen peroxide (H2O2) (1 and 3mM) in the presence or absence of CWC (200 and 400 μg/ml) and SA (40 μM) for the determination of antioxidative, DNA protective, cellular ROS level by modern methods, including immunoblot and flowcytometry to find out the possible mechanism of action.

RESULTS

Pre-treatment of hepatocyte with CWC and SA showed significant prevention of H2O2-induced intracellular ROS generation, nuclear DNA damage along with the formation of hepatic TBARS and cellular nitrite. Further, the H2O2 induced cell death was arrested in the presence of CWC through the inhibition of CDC42 mediated SAPK/JNK pathways and activation of other molecules of apoptotic pathways, including Bax and caspase3. Moreover, CWC and SA help in maintaining the GSH level and endogenous antioxidants like Mn-SOD, to support intracellular defense mechanisms, probably through the transcriptional activation of Nrf2; and inhibition of nuclear translocation of NF-κB.

CONCLUSION

CWC and its active components SA reversed the H2O2 induced oxidative damage in hepatocytes, probably through the inhibition of NF-κB, with the activation of PI3K/Akt/Nrf2 pathway and reduction of apoptosis by interfering the SAPK/JNK/Bax pathway.

The protective effect of Smilax glabra extract on advanced glycation end products-induced endothelial dysfunction in HUVECs via RAGE-ERK1/2-NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Smilax glabra Roxb. (SGR) is a traditional Chinese herb that has been used in folk for the treatment of diabetic vascular complications. Advanced glycation end products (AGEs)-induced endothelial dysfunction has been thought to be a major cause of diabetic vascular complications. The present study was conducted to investigate the protective effect of SGR extract on AGEs-induced endothelial dysfunction and its underlying mechanisms.

MATERIALS AND METHODS

Human umbilical vein endothelial cells (HUVECs) were exposed to 200 μg/ml AGEs to induce endothelial dysfunction. Acridine orange/ethidium bromide (AO/EB) fluorescence assay and Annexin-V/PI double-staining were performed to determine endothelium apoptosis. Dihydroethidium (DHE) fluorescence probe, SOD and MDA kits were used to evaluate oxidative stress. The effect of SGR extract on AGEs-induced TGF-beta1 expression was determined by immunocytochemistry and western blotting. Attenuations of SGR extract on receptor for AGEs (RAGE) expression, extracellular regulated protein kinases (ERK1/2) activation and NF-κB phosphorylation were determined by immunofluorescence assay and western blotting. The blockade assays for RAGE and ERK1/2 were carried out using a specific RAGE-antibody (RAGE-Ab) or a selective ERK1/2 inhibitor PD98059 in immunofluorescence assay.

RESULTS

The pretreatment of SGR extract (0.125, 0.25 and 0.5 mg crude drug/ml) significantly attenuated AGEs-induced endothelium apoptosis, and down-regulated TGF-beta1 protein expression in HUVECs. It was also well shown that SGR extract could down-regulate dose-dependently ROS over-generation, MDA content, TGF-beta1 expression, ERK1/2 and NF-κB activation whereas increase significantly SOD activity. Furthermore, the AGEs-induced ERK1/2 activation could be attenuated by the blockade of RAGE-Ab (5 μg/ml) while the NF-κB activation was ameliorated by ERK1/2 inhibitor PD98059 (10 μM).

CONCLUSION

These results indicated that SGR extract could attenuate AGEs-induced endothelial dysfunction via RAGE-ERK1/2-NF-κB pathways. Our findings suggest that SGR extract may be beneficial for attenuating endothelial dysfunction in diabetic vascular complications.

Short communication: antiviral activity of subcritical water extract of Brassica juncea against influenza virus A/H1N1 in nonfat milk

Subcritical water extract (SWE) of Brassica juncea was studied for antiviral effects against influenza virus A/H1N1 and for the possibility of application as a nonfat milk supplement for use as an "antiviral food." At maximum nontoxic concentrations, SWE had higher antiviral activity against influenza virus A/H1N1 than n-hexane, ethanol, or hot water (80°C) extracts. Addition of 0.5mg/mL of B. juncea SWE to culture medium led to 50.35% cell viability (% antiviral activity) for Madin-Darby canine kidney cells infected with influenza virus A/H1N1. Nonfat milk supplemented with 0.28mg/mL of B. juncea SWE showed 39.62% antiviral activity against influenza virus A/H1N1. Thus, the use of B. juncea SWE as a food supplement might aid in protection from influenza viral infection.

Serum reactive oxygen species modulator 1 (Romo1) as a potential diagnostic biomarker for non-small cell lung cancer

OBJECTIVES

Reactive oxygen species modulator 1 (Romo1) is a novel protein that localizes in the mitochondrial membrane and induces mitochondrial reactive oxygen species (ROS) generation. Romo1 is increased in most cancer cell lines and is related with resistance to chemotherapy in vitro. However, data on its expression in patients with malignancy is very limited. We evaluated the usefulness of serum Romo1 as a potential diagnostic biomarker in non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

We initially assessed the expression of Romo1 using Western blotting and enzyme-linked immunosorbent assay in paired lung tissue and serum specimen from NSCLC patients who underwent surgical resection. Then we evaluated and compared serum Romo1 level in a healthy population (n=55), patients with benign lung diseases (n=63) and NSCLC patients (n=58). We explored the correlation between Romo1 expression and clinical parameters and assessed diagnostic performance of serum Romo1 for NSCLC using receiver operating characteristic (ROC) curve analysis.

RESULTS

Romo1 expression in lung cancer tissues was significantly increased compared with non-tumorous tissues (p<0.001). Romo1 expression in cancer tissues positively correlated with that in serum (r=0.68, p=0.009). Serum Romo1 level in NSCLC patients significantly increased compared with that of healthy population or patients with benign lung diseases (both p<0.001). ROC curve analysis using an optimal cutoff value of 329.7 pg/mL revealed sensitivity and specificity for the diagnosis of NSCLC of 81.9% and 89.8%, respectively, with an area under the curve of 0.847 (95% confidence interval: 0.789-0.892, p<0.001). Serum Romo1 level was not related with age, gender, smoking status, tumor differentiation, histological type or stage.

CONCLUSIONS

Serum Romo1 discriminated NSCLC patients from the population without cancer with considerable sensitivity and specificity. Serum Romo1 could be a potential diagnostic biomarker for NSCLC.

Alzheimer's disease treated patients showed different patterns for oxidative stress and inflammation markers

Alzheimer's disease (AD) is the most common type of dementia accounting for 60-80% of the reported cases. The aim of this study was to evaluate levels of certain parameters of oxidative stress and markers of endothelial dysfunction in the blood of 21 AD patients under standard treatment compared with 10 controls, in an attempt to elucidate the contribution of AD to the total oxidative stress status of the patients. Results indicate that IL-6, TNF-α, ADMA and homocysteine levels were significantly elevated in AD patients. Protein carbonyls levels were higher in AD group, while glutathione reductase and total antioxidant capacity were lower, depicting decreased defense ability against reactive oxygen species. Besides, a higher level of advanced glycation end-products was observed in AD patients. Depending on the treatment received, a distinct inflammatory and oxidative stress profile was observed: in Rivastigmine-treated group, IL6 levels were 47% lower than the average value of the remaining AD patients; homocysteine and glutathione reductase were statistically unchanged in the Rivastigmine and Donepezil-Memantine, respectively Donepezil group. Although the study is based on a limited population, the results could constitute the basis for further studies regarding the effect of medication and diet on AD patients.

Membranar effects exerted in vitro by polyphenols - quercetin, epigallocatechin gallate and curcumin - on HUVEC and Jurkat cells, relevant for diabetes mellitus

Polyphenols are largely studied for their beneficial action in various pathologies, but the correlation with their effects on cell membranes is still elusive. In the present study we assessed the effects exerted in vitro by quercetin, epigallocatechin gallate and curcumin on membrane fluidity and transmembrane potential of human umbilical vein endothelial cells and Jurkat T lymphoblasts, in experimental conditions mimicking diabetes mellitus, i.e. high glucose conditions or increased concentration of advanced glycation end products. Results showed that the investigated polyphenols had beneficial effects on cell membranes altered in diabetic conditions, by restoring transmembrane potential and by membrane "stiffening". Moreover, they limited the release of pro-inflammatory factors, like monocyte chemotactic protein-1. These effects were more obvious for cells exposed to advanced glycation end products specific for the late stages of diabetes. Apparently, the inhibitory action of polyphenols on lipid peroxidation was associated with a decrease of membrane fluidity. Concluding, our in vitro study highlighted the potential beneficial action of polyphenols mainly in the late stages of diabetes, exerted at the level of membrane fluidity and transmembrane potential, accompanied by an anti-inflammatory effect on endothelial and immune cells.

Oxidative stress and cancer: an overview

Reactive species, which mainly include reactive oxygen species (ROS), are products generated as a consequence of metabolic reactions in the mitochondria of eukaryotic cells. In normal cells, low-level concentrations of these compounds are required for signal transduction before their elimination. However, cancer cells, which exhibit an accelerated metabolism, demand high ROS concentrations to maintain their high proliferation rate. Different ways of developing ROS resistance include the execution of alternative pathways, which can avoid large amounts of ROS accumulation without compromising the energy demand required by cancer cells. Examples of these processes include the guidance of the glycolytic pathway into the pentose phosphate pathway (PPP) and/or the generation of lactate instead of employing aerobic respiration in the mitochondria. Importantly, ROS levels can be used as a thermostat to monitor the damage that cells can bear. The implications for ROS regulation are highly significant for cancer therapy because commonly used radio- and chemotherapeutic drugs influence tumor outcome through ROS modulation. Moreover, the discovery of novel biomarkers that are able to predict the clinical response to pro-oxidant therapies is a crucial challenge to overcome to allow for the personalization of cancer therapies.

Phenylalanine ammonia lyase (PAL) enzyme activity and antioxidant properties of some cyanobacteria isolates

In the present study, six cyanobacteria isolates were evaluated for the PAL enzyme activity, and their methanol extracts were assessed for the total phenolic amount and other antioxidant parameters. Synechocystis sp. BASO444 and Synechocystis sp. BASO673 isolates with high levels of total phenols (66.0±1.2μg/mg, 78.1±1.8μg/mg, respectively) also showed high levels of PAL activities (20.5±3.1U/mg protein, 17.2±2.3U/mg protein, respectively) and strong antioxidant activities. To understand the effect of l-phenylalanine (l-phe) on the PAL activity, total phenolic amount, and phenolic constituents, isolates were evaluated with 100mg/l l-phe. While PAL activities exhibited no significant change with l-phe addition, total phenolic amount of the isolates significantly increased. HPLC analysis revealed gallic acid, trans-cinnamic acid, p-coumaric acid, and ferulic acid as the main compounds. Results suggested that the two isolate mights be an important source for the l-phe inducible phenolic compounds.

Quercetin and epigallocatechin gallate induce in vitro a dose-dependent stiffening and hyperpolarizing effect on the cell membrane of human mononuclear blood cells

The bioactivity of polyphenols is closely linked to their ability to interact with biological membranes. The study evaluates the in vitro effect of quercetin and epigallocatechin on the membrane anisotropy and transmembrane potential of peripheral blood mononuclear cells (PBMCs) isolated from 26 type 2 diabetes mellitus patients compared to 25 age matched controls. The in vitro assays were analyzed in correlation with the biochemical and inflammatory profile of the subjects and with insulin resistance parameters (HOMA-IR, plasma resistin) as well. For type 2 diabetes patients, the increase of HOMA-IR and resistin concentration was associated with a significant decrease of the PBMCs membrane anisotropy. The two tested polyphenols induced a dose-dependent hyperpolarizing effect and stiffening of the cell membranes for all tested subjects. Physiological levels of quercetin and epigallocatechin gallate had the tendency to normalize the PBMCs membrane anisotropy of the cells isolated from diabetes patients, bringing it to the level of cells isolated from normoglycemic ones. Epigallocatechin gallate induced higher effects compared to quercetin on the membranes isolated from subjects with higher cardiovascular risk. The decrease of membrane fluidity and the hyperpolarizing effect could explain the cardiovascular protective action of the tested compounds.