Bioactive Oligopeptides from Ginseng (Panax ginseng Meyer) Suppress Oxidative Stress-Induced Senescence in Fibroblasts via NAD+/SIRT1/PGC-1α Signaling Pathway

The physicochemical properties and multiple bioactive effects of ginseng oligopeptides (GOPs), plant-derived small molecule bioactive peptides, suggest a positive influence on health span and longevity. Given this, cellular senescence is the initiating factor and key mechanism of aging in the organism, and thus the current study sought to explore the effects of GOPs on H₂O₂-induced cellular senescence and its potential mechanisms. Senescence was induced in mouse embryonic fibroblasts NIH/3T3 by 4 h of exposure to 200 µM H₂O₂ and confirmed using CCK-8 assay and Western blot analyses of p16^INK4A and p21^Waf1/Cip1 after 24 h of growth medium administration with or without GOPs supplementation (25, 50, and 100 µg/mL). We found that GOPs delayed oxidative stress-induced NIH/3T3 senescence by inhibiting the G1 phase arrest, increasing DNA synthesis in the S phase, decreasing the relative protein expression of p16^INK4A and p21^Waf1/Cip1, promoting cell viability, protecting DNA, and enhancing telomerase (TE) activity. Further investigation revealed that the increase in antioxidative capacity and anti-inflammation capacity might form the basis for the retarding of the senescence effects of GOPs. Furthermore, GOPs supplementation significantly improved mitochondrial function and mitochondrial biogenesis via the NAD⁺/SIRT1/PGC-1𝛼 pathway. These findings indicate that GOPs may have a positive effect on health span and lifespan extension via combating cellular senescence, oxidative stress, and inflammation, as well as modulating longevity regulating pathway NAD⁺/SIRT1/PGC-1𝛼.     

Bitter taste receptors protect against skin aging by inhibiting cellular senescence and enhancing wound healing

BACKGROUND/OBJECTIVESBitter taste receptors are taste signaling pathway mediators, and are also expressed and function in extra-gustatory organs. Skin aging affects the quality of life and may lead to medical issues. The purpose of this study was to better understand the anti-skin aging effects of bitter taste receptors in D-galactose (D-gal)-induced aged human keratinocytes, HaCaT cells.MATERIALS/METHODSExpressions of bitter taste receptors in HaCaT cells and mouse skin tissues were examined by polymerase chain reaction assay. Bitter taste receptor was overexpressed in HaCaT cells, and D-gal was treated to induce aging. We examined the effects of bitter taste receptors on aging by using β-galactosidase assay, wound healing assay, and Western blot assay.RESULTSTAS2R16 and TAS2R10 were expressed in HaCaT cells and were upregulated by D-gal treatment. TAS2R16 exerted protective effects against skin aging by regulating p53 and p21, antioxidant enzymes, the SIRT1/mechanistic target of rapamycin pathway, cell migration, and epithelial-mesenchymal transition markers. TAS2R10 was further examined to confirm a role of TAS2R16 in cellular senescence and wound healing in D-gal-induced aged HaCaT cells.CONCLUSIONSOur results suggest a novel potential preventive role of these receptors on skin aging by regulating cellular senescence and wound healing in human keratinocyte, HaCaT.     

Oligonol promotes anti-aging pathways via modulation of SIRT1-AMPK-Autophagy Pathway

BACKGROUND/OBJECTIVESOligonol, mainly found in lychee fruit, is an antioxidant polyphenolic compound which has been shown to have anti-inflammatory and anti-cancer properties. The detailed mechanisms by which oligonol may act as an anti-aging molecule have not been determined.MATERIALS/METHODSIn this study, we evaluated the ability of oligonol to modulate sirtuin (SIRT) expression in human lung epithelial (A549) cells. Oligonol was added to A549 cells and reactive oxygen species production, mitochondrial superoxide formation, and p21 protein levels were measured. Signaling pathways activated upon oligonol treatment were also determined by western blotting. Furthermore, the anti-aging effect of oligonol was evaluated ex vivo in mouse splenocytes and in vivo in Caenorhabditis elegans.RESULTSOligonol specifically induced the expression of SIRT1, whose activity is linked to gene expression, metabolic control, and healthy aging. In response to influenza virus infection of A549 cells, oligonol treatment significantly up-regulated SIRT1 expression and down-regulated viral hemagglutinin expression. Oligonol treatment also resulted in the activation of autophagy pathways and the phosphorylation of AMP-activated protein kinase (AMPK). Furthermore, oligonol-treated spleen lymphocytes from old mice showed increased cell proliferation, and mRNA levels of SIRT1 in the lungs of old mice were significantly lower than those in the lungs of young mice. Additionally, in vivo lethality assay revealed that oligonol extended the lifespan of C. elegans infected with lethal Vibrio cholerae.CONCLUSIONSThese data demonstrated that oligonol may act as an anti-aging molecule by modulating SIRT1/autophagy/AMPK pathways.     

Apple polyphenol protects against cigarette smoke-induced acute lung injury

ObjectiveChronic obstructive pulmonary disease (COPD) is a complex chronic inflammatory disease involving oxidative stress as well as a wide variety of cells activated from smoking cigarettes. There have been disappointingly few therapeutic advances in drug therapy for COPD. Plant polyphenols have been the topic of much research regarding their antioxidant activities and antiinflammatory and immunomodulatory effects. In the present study, we ask whether apple polyphenol provides protection against cigarette smoke (CS)-induced acute lung injury.MethodsICR mice were exposed to CS for 4 d with increasing exposure time for up to 6 h per day to elicit epithelial cells injury. One hour before smoke exposure, mice were treated with apple polyphenol (APP) by gavage; all examinations were performed 18 h after the last CS exposure.ResultsAPP at 30, 100, or 300 mg not only significantly dose-dependently reduced the CS-induced accumulation of inflammatory cells and gene/protein expression of proinflammatory factors both in the lung and in bronchoalveolar lavage fluid, but also significantly reversed oxidative stress in the lungs. Additionally, treatment with APP also significantly regulated the CS-induced imbalance of matrix metalloproteinases-9/tissue inhibitor of metalloproteinase-1 expression in the lungs. To investigate further the possible signaling pathway of APP effects, we examined protein expression of p-P38 MAPK by immunohistochemistry that found treatment with APP significantly decreased the CS-induced increases of p-P38 expression in the lungs.ConclusionTaken together, APP may be a potential dietary nutrient supplement agent to improve quality of life of COPD patients by inhibiting CS-exposed acute lung injury via P38 MAPK signaling pathway.     

Daily Vegetables Intake and Response to COPD Rehabilitation. The Role of Oxidative Stress,Inflammation and DNA Damage

Chronic obstructive pulmonary disease (COPD) is a respiratory disease associated with airways inflammation and lung parenchyma fibrosis. The primary goals of COPD treatment are to reduce symptoms and risk of exacerbations, therefore pulmonary rehabilitation is considered the key component of managing COPD patients. Oxidative airway damage, inflammation and reduction of endogenous antioxidant enzymes are known to play a crucial role in the pathogenesis of COPD. Recently, also natural antioxidants have been considered as they play an important role in metabolism, DNA repair and fighting the effects of oxidative stress. In this paper we evaluated the response of 105 elderly COPD patients to pulmonary rehabilitation (PR), based on high or low vegetable consumption, by analyzing clinical parameters and biological measurements at baseline and after completion of the three weeks PR. We found that daily vegetable intake in normal diet, without any specific intervention, can increase the probability to successfully respond to rehabilitation (65.4% of responders ate vegetables daily vs. 40.0% of non-responders, p = 0.033). The association was especially evident in subjects ≥ 80 year of age (OR = 17.0; p < 0.019). Three weeks of pulmonary rehabilitation are probably too short to reveal a reduction of the oxidative stress and DNA damage, but are enough to show an improvement in the patient’s inflammatory state.     

Palm Fruit Bioactive Complex (PFBc), a Source of Polyphenols,Demonstrates Potential Benefits for Inflammaging and Related Cognitive Function

Cognitive function is a key aspect of healthy aging. Inflammation associated with normal aging, also called inflammaging is a primary risk factor for cognitive decline. A diet high in fruits and vegetable and lower in calories, particularly a Mediterranean Diet, may lower the risk of age-related cognitive decline due in part to the associated high intake of antioxidants and polyphenols. A phenolic, Palm Fruit Bioactive complex (PFBc) derived from the extraction process of palm oil from oil palm fruit (Elaeis guineensis), is reported to offset inflammation due to its high antioxidant, especially vitamin E, and polyphenol content. The benefit is thought to be achieved via the influence of antioxidants on gene expression. It is the purpose of this comprehensive review to discuss the etiology, including gene expression, of mild cognitive impairment (MCI) specific to dietary intake of antioxidants and polyphenols and to focus on the potential impact of nutritional interventions specifically PFBc has on MCI. Several in vitro, in vivo and animal studies support multiple benefits of PFBc especially for improving cognitive function via anti-inflammatory and antioxidant mechanisms. While more human studies are needed, those completed thus far support the benefit of consuming PFBc to enhance cognitive function via its anti-inflammatory antioxidant functions.     

Potential of Polyphenols to Restore SIRT1 and NAD+ Metabolism in Renal Disease

SIRT1 is an NAD⁺-dependent class III histone deacetylase that is abundantly expressed in the kidney, where it modulates gene expression, apoptosis, energy homeostasis, autophagy, acute stress responses, and mitochondrial biogenesis. Alterations in SIRT1 activity and NAD⁺ metabolism are frequently observed in acute and chronic kidney diseases of diverse origins, including obesity and diabetes. Nevertheless, in vitro and in vivo studies and clinical trials with humans show that the SIRT1-activating compounds derived from natural sources, such as polyphenols found in fruits, vegetables, and plants, including resveratrol, quercetin, and isoflavones, can prevent disease and be part of treatments for a wide variety of diseases. Here, we summarize the roles of SIRT1 and NAD⁺ metabolism in renal pathophysiology and provide an overview of polyphenols that have the potential to restore SIRT1 and NAD⁺ metabolism in renal diseases.     

Hesperetin suppresses LPS/high glucose-induced inflammatory responses via TLR/MyD88/NF-κB signaling pathways in THP-1 cells

BACKGROUND/OBJECTIVESUnregulated inflammatory responses caused by hyperglycemia may induce diabetes complications. Hesperetin, a bioflavonoid, is a glycoside in citrus fruits and is known to have antioxidant and anticarcinogenic properties. However, the effect of inflammation on the diabetic environment has not been reported to date. In this study, we investigated the effect of hesperetin on proinflammatory cytokine secretion and its underlying mechanistic regulation in THP-1 macrophages with co-treatment LPS and hyperglycemic conditions.MATERIALS/METHODSTHP-1 cells differentiated by PMA (1 μM) were cultured for 48 h in the presence or absence of hesperetin under normoglycemic (5.5 mM/L glucose) or hyperglycemic (25 mM/L glucose) conditions and then treated with LPS (100 ng/mL) for 6 h before harvesting. Inflammation-related proteins and mRNA levels were evaluated by enzyme-linked immunosorbent assay, western blot, and quantitative polymerase chain reaction analyses.RESULTSHesperetin (0–100 μM, 48 h) treatment did not affect cell viability. The tumor necrosis factor-α and interleukin-6 levels increased in cells co-treated with LPS under hyperglycemic conditions compared to normoglycemic conditions, and these increases were decreased by hesperetin treatment. The TLR2/4 and MyD88 activity levels increased in cells co-treated with LPS under hyperglycemic conditions compared to normoglycemic conditions; however, hesperetin treatment inhibited the TLR2/4 and MyD88 activity increases. In addition, nuclear factor-κB (NF-κB) and Acetyl-NF-κB levels increased in response to treatment with LPS under hyperglycemic conditions compared to normoglycemic conditions, but those levels were decreased when treated with hesperetin. SIRT3 and SIRT6 expressions were increased by hesperetin treatment.CONCLUSIONSOur results suggest that hesperetin may be a potential agent for suppressing inflammation in diabetes.     

Biomarkers in obstructive respiratory diseases: an update

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation of the airways, with the involvement of many inflammatory cells and mediators. Traditionally, this inflammation is thought to spread to a systemic level, thus inducing damage of different organs. However, other pathogenetic mechanisms could take part to the above-described process, and some open questions need to be solved. Due to the burden and increasing prevalence of COPD, the opportunity to find biomarkers that can potentially be useful in identifying individuals with the disease, or better, prior to symptoms onset, to diagnose and properly manage the respiratory symptoms, as well as to evaluate the response to treatment and to select specific subtypes of patients for tailored treatments is strongly advocated. Several mediators, enzymes, hormones and cells have been claimed to adhere to this objective. Moreover, the presence of comorbid or concomitant diseases can variably influence the concentration of specific biomarkers in samples of individuals with COPD, and age-related functional and structural changes (inflammaging) can further confuse the biological pattern. Several observations have been performed in the last decades; nevertheless, no biomarker is currently considered as satisfying all the above-mentioned issues. The "Evaluation of COPD longitudinally to identify predictive surrogates and points (ECLIPSE)" study has specifically explored the possibility to identify novel biomarkers that correlate with clinically relevant COPD subtypes and with markers of disease progression. Among the thirty-four biomarkers considered, 15 resulted to be increased in COPD patients rather than in smoker and non-smoker controls. Specific lung proteins such as CC-16 and SPD are promising in detecting lung damage, exacerbation susceptibility or responsiveness to treatment. The ECLIPSE findings confirm that, to date, the use of a single biomarker is not sufficient, but the combination of novel biomarkers with the already existing tools could improve our skills in optimizing treatment of COPD patients.     

Circulating visfatin in chronic obstructive pulmonary disease

ObjectiveMalnutrition and continuous systemic inflammation occur frequently in patients with chronic obstructive pulmonary disease (COPD). Visfatin is a new adipokine, which increases in some inflammatory diseases. Its plasma level and relation with nutritional status and inflammation in COPD remain unknown. This study compared visfatin levels, nutritional status, and inflammation markers in patients with COPD and healthy controls.MethodsPlasma visfatin, tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) were measured in 35 patients with COPD and 28 healthy controls. Body composition was assessed with bioelectrical impedance analysis.ResultsSignificantly lower body mass index and percentage of body fat were observed in patients with COPD compared with control subjects. The levels of plasma visfatin were higher in the COPD group compared with healthy controls (2.07 ± 0.18 versus 1.88 ± 0.15 ng/mL, P < 0.001). Levels of TNF-α and CRP were also significantly higher in patients with COPD compared with controls. Plasma CRP and TNF-α were positively correlated with visfatin in the COPD group. No significant correlations were found between visfatin and body mass index or percentage of body fat in both groups.ConclusionPlasma visfatin levels increased in patients with COPD. This increased adipocytokine was significantly correlated with TNF-α and CRP. Visfatin may be a new proinflammatory adipocytokine in this disease.     

SIRT1通过抑制卵母细胞衰老改善卵巢储备功能的研究进展

卵母细胞衰老及卵巢储备功能降低所造成的生育力下降是生殖领域的瓶颈问题,改善卵巢储备功能是提高不孕女性自然妊娠率及辅助生殖技术(ART)成功率的重要因素。沉默信息调节因子2相关酶类1(SIRT1)是调节卵子发生和细胞应激反应关键过程的重要参与者,可通过调控卵母细胞数量、改善卵母细胞质量、抑制氧化应激、调节线粒体功能等途径抑制卵母细胞衰老,提高卵巢储备功能,延长卵巢寿命,进而增加ART过程中的获卵数、成胚率及临床妊娠率。综述SIRT1通过抑制卵母细胞衰老改善卵巢储备功能的相关机制研究进展。     

Diet and SIRT1 Genotype Interact to Modulate Aging-Related Processes in Patients with Coronary Heart Disease: From the CORDIOPREV Study

We investigated whether long-term consumption of two healthy diets (low-fat (LF) or Mediterranean (Med)) interacts with SIRT1 genotypes to modulate aging-related processes such as leucocyte telomere length (LTL), oxidative stress (OxS) and inflammation in patients with coronary heart disease (CHD). LTL, inflammation, OxS markers (at baseline and after 4 years of follow-up) and SIRT1-Single Nucleotide Polymorphisms (SNPs) (rs7069102 and rs1885472) were determined in patients from the CORDIOPREV study. We analyzed the genotype-marker interactions and the effect of diet on these interactions. Regardless of the diet, we observed LTL maintenance in GG-carriers for the rs7069102, in contrast to carriers of the minor C allele, where it decreased after follow-up (p = 0.001). The GG-carriers showed an increase in reduced/oxidized glutathione (GSH/GSSG) ratio (p = 0.003), lower lipid peroxidation products (LPO) levels (p < 0.001) and a greater decrease in tumor necrosis factor-alpha (TNF-α) levels (p < 0.001) after follow-up. After the LF diet intervention, the GG-carriers showed stabilization in LTL which was significant compared to the C allele subjects (p = 0.037), although the protective effects found for inflammation and OxS markers remained significant after follow-up with the two diets. Patients who are homozygous for the SIRT1-SNP rs7069102 (the most common genotype) may benefit from healthy diets, as suggested by improvements in OxS and inflammation in patients with CHD, which may indicate the slowing-down of the aging process and its related diseases.     

Sirtuin1功能及调控研究进展

Sirtuin1(SIRT1)是依赖于烟酰胺腺嘌呤二核苷酸辅酶(nicotinamide adenine dinucleotide,NAD+)的去乙酰化酶(Sirtuins,SIRTs)家族7个成员中最大的一个,是近年来研究最为广泛的长寿因子。SIRT1除了对组蛋白赖氨酸残基去乙酰化修饰调节表观遗传外,SIRT1还可以调节细胞其他关键蛋白活性,控制细胞增殖、分化和细胞凋亡等生理功能。最近研究发现,SIRT1调控细胞功能除了与其酶活性水平有关,也可能与其在细胞中的定位有关。SIRT1在细胞核质之间穿梭和SIRT1活性水平及其相对应的生理功能仍需深入研究.     

Identification of a complex population of chromatin-associated proteins in the European sea bass (Dicentrarchus labrax) sperm

ABSTRACT

A very common conception about the function of the spermatozoon is that its unique role is to transmit the paternal genome to the next generation. Most of the sperm genome is known to be condensed in many species by protamines, which are small and extremely positively charged proteins (50–70% arginine) with the functions of streamlining the sperm cell and protecting its DNA. However, more recently, it has been shown in mammals that 2–10% of its mature sperm chromatin is also associated to a complex population of histones and chromatin-associated proteins differentially distributed in the genome. These proteins are transferred to the oocyte upon fertilization and may be involved in the epigenetic marking of the paternal genome. However, little information is so far available on the additional potential sperm chromatin proteins present in other protamine-containing non-mammalian vertebrates detected through high-throughput mass spectrometry. Thus, we started the present work with the goal of characterizing the mature sperm proteome of the European sea bass, with a particular focus on the sperm chromatin, chosen as a representative of non-mammalian vertebrate protamine-containing species. Proteins were isolated by acidic extraction from purified sperm cells and from purified sperm nuclei, digested with trypsin, and subsequently the peptides were separated using liquid chromatography and identified through tandem mass spectrometry. A total of 296 proteins were identified. Of interest, the presence of 94 histones and other chromatin-associated proteins was detected, in addition to the protamines. These results provide phylogenetically strategic information, indicating that the coexistence of histones, additional chromatin proteins, and protamines in sperm is not exclusive of mammals, but is also present in other protamine-containing vertebrates. Thus, it indicates that the epigenetic marking of the sperm chromatin, first demonstrated in mammals, could be more fundamental and conserved than previously thought.

Abbreviations: AU-PAGE: acetic acid–urea polyacrylamide gel electrophoresis; CPC: chromosomal passenger complex; DTT: dithiothreitol; EGA: embryonic genome activation; FDR: false discovery rate; GO: Gene Ontology; IAA: iodoacetamide; LC: liquid chromatography; LC-MS/MS: liquid chromatography coupled to tandem mass spectrometry; MS: mass spectrometry; MS/MS: tandem mass spectrometry; MW: molecular weight; PAGE: polyacrylamide gel electrophoresis; PBS: phosphate buffered saline; SDS: sodium dodecyl sulfate; SDS-PAGE: sodium dodecyl sulfate polyacrylamide gel electrophoresis; TCA: trichloroacetic acid.     

Histone H4 Acetylation is Essential to Proceed from a Histone- to a Protamine-based Chromatin Structure in Spermatid Nuclei of Drosophila melanogaster

In humans, other mammals, and also in Drosophila, the paternal genome in the sperm is highly condensed and organized mainly in a protamine-based chromatin structure. However, the timing and mechanism of the switch from a histone- to the protamine-based chromatin configuration is still poorly understood. We therefore established Drosophila in vitro cultures of cysts with 64 synchronously developing spermatids genetically marked with histone H2AvD-RFP and ProtamineB-eGFP. Live cell imaging showed that the switch from H2AvD-RFP to Protamine-eGFP chromatin takes approximately five hours, with a short but clear overlap of the presence of both histones and protamines. Moreover, cultured pupal testes showed H4 hyperacetylation at the canoe stage shortly before histone removal; a feature previously observed in the intact animal. We then used TSA to inhibit histone deacetylation and found that premature hyperacetylation was already induced at the round nuclei stage of spermatids. However, this premature hyperacetylation did not lead to a premature switch to the protamine-based chromatin structure, showing that histone hyperacetylation is not the sole inducer of the histone to protamine switch. Importantly, we observed that inactivation of histone acetyltransferases by anacardic acid blocks further differentiation and thus prevents the degradation of histones and the switch to a protamine-based chromatin. Thus, we conclude that H4 hyperacetylation is an essential feature but not the sole inducer of the histone to protamine switch during spermiogenesis.     

H3K4me2 accompanies chromatin immaturity in human spermatozoa: an epigenetic marker for sperm quality assessment

ABSTRACT

Chromatin remodeling, including histone post-translational modifications, during spermatogenesis can affect sperm quality and fertility, and epigenetic marks may therefore be useful for clinical evaluations of sperm. Together with histone hyperacetylation, the dimethylation of histone H3 on lysine K4 (H3K4me2) is also required during protamination. Accordingly, we evaluated the utilization of this epigenetic mark for the identification of sperm with decrease quality and immature chromatin. In this study, 99 semen samples, including 22 normozoospermic (N), 63 asthenozoospermic (A), and 14 oligoasthenozoospermic (OA) samples, were comprehensively analyzed with respect to H3K4me2 levels, DNA damage (DNA fragmentation index, DFI), and sperm immaturity (high DNA stainability, %HDS), as determined by a sperm chromatin structure assay using flow cytometry. We detected a significant relationship between H3K4me2 and %HDS (r = 0.47; p < 0.001). Furthermore, we observed negative correlations between H3K4me2 and sperm concentration, motility, and mitochondrial activity (p < 0.05). The increase in immaturity as semen quality decreased (N > A > OA) indicates the importance of chromatin immaturity and histone code deviations in sperm evaluations. Using various approaches, our study elucidated H3K4me2 as a molecular marker of sperm quality with potential use in reproductive medicine.

Abbreviations: A: asthenozoospermic; AO: acridine orange; ART: assisted reproductive therapy; BWW: Biggers-Whitten Whittingham; DAPI: 4?,6? -diamidino-2-phenylindole; DFI: DNA fragmentation index; H3K4me2: dimethylation of lysine K4 on histones H3; HDS: high DNA stainability; HRP: horseradish peroxidase; MACS: magnetic-activated cell sorting; N: normospermic; NGS: normal goat serum; OA: oligoasthenozoospermic; PTM: post-translational modification; SCSA: sperm chromatin structure assay; SUTI: sperm ubiquitin tag assay; TBS-T: TBS with 0.5% Tween-20     

Senescence mediated redox imbalance in cardiac tissue: Antioxidant rejuvenating potential of green tea extract

ObjectiveThe activities and capacities of antioxidant systems of tissue cells are declined during aging, leading to the gradual loss of pro-oxidant/antioxidant balance and accumulation of oxidative damage. Hence, the present study evaluated the role of green tea extract (GTE), rich in polyphenols, in combating age-associated macromolecular damage in rat cardiac tissue.MethodsThe antioxidant defense system, lipid peroxidation, protein oxidation, and redox status in heart tissue were studied using young and aged rats.ResultsSignificant increases in lipid peroxidation, protein carbonyls, and marked decreases in glutathione redox status, protein thiols, and activities of enzymatic and non-enzymatic antioxidants were observed in aged rats compared with young rats. Supplementation of GTE (100 mg/kg of body weight per day) orally for 30 days ameliorated these changes significantly.ConclusionThis study accredits GTE's antioxidant rejuvenating potency and its role in the amelioration of senescence-mediated redox imbalance in aged rat cardiac tissue.     

Effect of complex polyphenols and tannins from red wine on DNA oxidative damage of rat colon mucosa in vivo

Summary Background: Dietary polyphenols have been reported to have a variety of biological actions, including anti-carcinogenic, antioxidant and anti-inflammatory activities. Aim of the study: In the present study we have evaluated the effect of an oral treatment with complex polyphenols and tannins from red wine and tea on DNA oxidative dammage in the rat colon mucosa. Methods: Isolated colonocytes were prepared from the colon mucosa of rats treated for ten days with either wine complex polyphenols (57.2 mg/kg/d) or thearubigin (40 mg/kg/d) by oral gavage. Colonocyte oxidative DNA damage was analysed at the single cell level using a modification of the comet assay technique. Results: These results show that wine complex polyphenols and tannins induce a significant decrease (−62% for pyrimidine and −57% for purine oxidation) in basal DNA oxidative damage in colon mucosal cells without affecting the basal level of single-strand breaks. On the other hand, tea polyphenols, namely a crude extract of thearubigin, did not affect either strand breaks or pyrimidine oxidation in colon mucosal cells. Conclusions Our experiments are the first demonstration that dietary polyphenols can modulate in vivo oxidative damage in the gastrointestinal tract of rodents. These data support the hypothesis that dietary polyphenols might have both a protective and a therapeutic potential in oxidative damage-related pathologies. Received: 17 April 2000, Accepted: 27 July 2000     

Antioxidant and radical scavenging properties in vitro of polyphenolic extracts from red wine

Summary Background & Aims Red wine polyphenols inhibit chemically-induced oxidative DNA damage in vivo in experimental animals through a mechanism which is still unclear. On this basis, we tried to clarify the mechanisms of inhibition of DNA oxidation in vitro by wine extracts containing monomeric and polymeric phenols (WE) and monomer-free complex polyphenols and tannins (WCPT) from red wine. Methods Oxidative DNA damage was induced by incubating DNA with GSH/Fe³⁺ or cumene hydroperoxide (CumOOH) in vitro and using 8-OH–2-deoxyguanosine (8-OHdG) levels as a measure of DNA oxidation. Levels of 8-OHdG were determined by HPLC coupled with electrochemical detector (ESA). Results and conclusions WCPT and WE, at μM concentrations, reduced concentration-dependently oxidative DNA damage induced by GSH/Fe³⁺. WCPT and WE also reduced DNA oxidation by CumOOH. In conclusion, complex polyphenols and tannin extracts from red wine, with or without small molecular phenols, prevent oxidative DNA damage through a dual mechanism, iron binding and direct free radical scavenging. Received: 27 November 2000 / Accepted: 11 April 2001