cyanidin-3-o-beta-glucopyranoside and protocatechuic-acid

Formation of advanced glycation end products (AGEs), which are associated with diabetes mellitus, contributes to prominent features of osteoarthritis, i.e., inflammation-mediated destruction of articular cartilage. Among the phytochemicals which play a role in anti-inflammatory effects, anthocyanins have also been demonstrated to have anti-diabetic properties. Purple corn is a source of three major anthocyanins: cyanidin-3-O-glucoside, pelargonidin-3-O-glucoside and peonidin-3-O-glucoside. Purple corn anthocyanins have been demonstrated to be involved in the reduction of diabetes-associated inflammation, suggesting that they may have a beneficial effect on diabetes-mediated inflammation of cartilage. This investigation of the chondroprotective effects of purple corn extract on cartilage degradation found a reduction in glycosaminoglycans released from AGEs induced cartilage explants, corresponding with diminishing of uronic acid loss of the cartilage matrix. Investigation of the molecular mechanisms in human articular chondrocytes showed the anti-inflammatory effect of purple corn anthocyanins and the metabolite, protocatechuic acid (PCA) on AGEs induced human articular chondrocytes via inactivation of the NFκb and MAPK signaling pathways. This finding suggests that purple corn anthocyanins and PCA may help ameliorate AGEs mediated inflammation and diabetes-mediated cartilage degradation.

Topics: Anthocyanins; Cartilage; Cell Line; Chondrocytes; Diabetes Complications; Diabetes Mellitus; Glucosides; Glycation End Products, Advanced; Glycosaminoglycans; Humans; Hydroxybenzoates; Inflammation; MAP Kinase Signaling System; NF-kappa B; Osteoarthritis; Zea mays

The aim of this study was to investigate the mechanism of action of cyanidin-3-O-glucoside (C3G) and its metabolite protocatechuic acid (PCA) mediated protection against 2-amino-3-methylimidazo[4,5-f]quinoline (IQ)-induced cytotoxicity in HepG2 cells. The effects of C3G and PCA on cell viability, LDH release and apoptosis in IQ-induced HepG2 cells were evaluated using CCK-8, LDH release and flow cytometry assays, respectively. TMT-based proteomics was utilized to characterize the proteins and pathways associated with the improvement after C3G and PCA treatment. Results showed that exposure to IQ significantly increased cytotoxicity and apoptosis in HepG2 cells, which were alleviated by C3G and PCA. C3G was more effective than PCA in protecting HepG2 cells against IQ-induced cytotoxicity and regulating the related signaling pathways. Proteomics and bioinformatics analyses and Western blot validation revealed that apoptosis-related signaling pathways played pivotal roles in protecting against the cytotoxicity of IQ by C3G, and XIAP was identified as the target protein. Molecular docking proved that C3G had strong binding affinity to XIAP and hindered the binding of IQ to the BIR3 domain of XIAP, resulting in the inhibition of apoptosis. Our findings suggested that C3G has potential as a preventive food ingredient to prevent carcinogenic risk of heterocyclic aromatic amines.

Topics: Anthocyanins; Apoptosis; Cell Survival; Computational Biology; Hep G2 Cells; Humans; Hydroxybenzoates; Molecular Docking Simulation; Protective Agents; Protein Binding; Protein Interaction Maps; Proteome; Proteomics; Quinolines; X-Linked Inhibitor of Apoptosis Protein

Previous studies indicated that cyanidin-3-O-β-glucoside (C3G) as a classical anthocyanin exerted an anti-fibrotic effect in the liver, but its bioavailability was quite low. This study was undertaken to explore the restraining effect of C3G and its metabolite protocatechuic acid (PCA) on the activation of hepatic stellate cells (HSCs). Our data demonstrated that the treatment of a carbon tetrachloride-treated mice model with C3G inhibited liver fibrosis and HSC activation. In vitro, both C3G and PCA preserved the lipid droplets and retinol in primary HSCs, and additionally inhibited the mRNA expression of α-smooth muscle actin and collagen I, but elevated the level of matrix metalloproteinase-2 and liver X receptors. Only PCA suppressed the levels of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) secreted from HSCs significantly. In addition, C3G and PCA inhibited the proliferation and migration of HSCs. In conclusion, PCA mainly explained the in vivo inhibiting effect of C3G on HSC activation and liver fibrosis.

Topics: Animals; Anthocyanins; Carbon Tetrachloride; Cell Movement; Cell Proliferation; Cells, Cultured; Drug Synergism; Glucosides; Hepatic Stellate Cells; Humans; Hydroxybenzoates; Interleukin-6; Liver Cirrhosis; Male; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Tumor Necrosis Factor-alpha

Foodstuffs of both plant and animal origin contain a wide range of bioactive compounds. Although human intervention studies are mandatory to assess the health effects of bioactives, the in vitro approach is often used to select the most promising molecules to be studied in vivo. To avoid misleading results, concentration and chemical form, exposure time, and potential cytotoxicity of the tested bioactives should be carefully set prior to any other experiments.. In this study the possible cytotoxicity of different bioactives (docosahexaenoic acid, propionate, cyanidin-3-O-glucoside, protocatechuic acid), was investigated in HepG2 cells using different methods. Bioactives were supplemented to cells at different concentrations within the physiological range in human blood, alone or in combination, considering two different exposure times.. Reported data clearly evidence that in vitro cytotoxicity is tightly related to the exposure time, and it varies among bioactives, which could exert a cytotoxic effect even at a concentration within the in vivo physiological blood concentration range. Furthermore, co-supplementation of different bioactives can increase the cytotoxic effect.. Our results underline the importance of in vitro cytotoxicity screening that should be considered mandatory before performing studies aimed to evaluate the effect of bioactives on other cellular parameters. Although this study is far from the demonstration of a toxic effect of the tested bioactives when administered to humans, it represents a starting point for future research aimed at verifying the existence of a potential hazard due to the wide use of high doses of multiple bioactives.

Topics: Anthocyanins; Biological Factors; Biomedical Research; Cell Survival; Docosahexaenoic Acids; Glucosides; Hep G2 Cells; Humans; Hydroxybenzoates; Models, Biological; Propionates; Toxicity Tests

Blueberries are a rich source of anthocyanins (ACNs) and phenolic acids (PA), which are hypothesized to protect against development of atherosclerosis. The present study examined the effect of an ACN- and PA-rich fractions, obtained from a wild blueberry powder, on the capacity to counteract lipid accumulation in macrophages derived from monocytic THP-1 cells. In addition, we tested the capacity of pure ACNs and their metabolites to alter lipid accumulation.. THP-1-derived macrophages were incubated with fatty acids (500 μM oleic/palmitic acid, 2:1 ratio) and different concentrations (from 0.05 to 10 μg mL(-1)) of ACN- and PA-rich fractions, pure ACN standards (malvidin, delphinidin and cyanidin 3-glucoside), and metabolites (syringic, gallic and protocatechuic acids). Lipid accumulation was quantified with the fluorescent dye Nile red.. Lipid accumulation was reduced at all concentrations of the ACN-rich fraction tested with a maximum reduction at 10 μg mL(-1) (-27.4%; p < 0.0001). The PA-rich fraction significantly reduced the lipid accumulation only at the low concentrations from 0.05 µg mL(-1) to 0.3 µg mL(-1), with respect to the control with fatty acids. Supplementation with pure ACN compounds (malvidin and delphinidin-3-glucoside and its metabolic products (syringic and gallic acid)) reduced lipid accumulation especially at the low concentrations, while no significant effect was observed after cyanidin-3-glucoside and protocatechuic acid supplementation.. The results demonstrated a potential role of both the ACN- and PA-rich fractions and single compounds in the lipid accumulation also at concentrations close to that achievable in vivo.

Topics: Anthocyanins; Antioxidants; Atherosclerosis; Blueberry Plants; Carotenoids; Cell Line, Tumor; Cell Survival; Dietary Fiber; Dietary Sucrose; Fatty Acids; Gallic Acid; Glucosides; Humans; Hydroxybenzoates; Lipid Metabolism; Macrophages; Plant Extracts; Powders; Protective Agents; Trace Elements; Vitamins

Cyanidin-3-glucoside (C3G) is a major anthocyanin in berries and a potential nutritional supplement for preventing retinal degeneration. However, the protective mechanism of C3G and its metabolites, protocatechuic acid (PCA) and ferulic acid (FA), remain unclear. The molecular mechanisms of C3G and its metabolites against retinal photooxidative damage in vivo are investigated.. Pigmented rabbits were orally administered C3G, PCA, and FA (0.11 mmol/kg/day) for 3 weeks. Electroretinography, histological analysis, and TUNEL assay showed that C3G and its metabolites attenuated retinal cell apoptosis. The expression of oxidative stress markers were upregulated after light exposure but attenuated by C3G and FA, which may be attributed to the elevated secretion and expression of heme oxygenase (HO-1) and nuclear factor erythroid-2 related factor 2 (Nrf2). C3G, PCA, and FA attenuated the secretion or expression of inflammation-related genes; FA suppressed nuclear factor kappa B (NF-κB) activation. The treatments attenuated the light-induced changes on certain apoptotic proteins and angiogenesis-related cytokines.. C3G and FA reduced light-induced retinal oxidative stress by activating the Nrf2/HO-1 antioxidant pathway. FA attenuated the light-induced retinal inflammation by suppressing NF-κB activation. C3G and its metabolites attenuated the photooxidation-induced apoptosis and angiogenesis in the retina.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Anthocyanins; Antioxidants; Apoptosis; Coumaric Acids; Cytokines; Deoxyguanosine; Glucosides; Heme Oxygenase-1; Hydroxybenzoates; In Situ Nick-End Labeling; Light; NF-E2-Related Factor 2; NF-kappa B; Oxidative Stress; Rabbits; Retina; Retinal Degeneration; Signal Transduction; Tyrosine; Up-Regulation

In vitro and in vivo studies suggest that dietary anthocyanins modulate cardiovascular disease risk; however, given anthocyanins extensive metabolism, it is likely that their degradation products and conjugated metabolites are responsible for this reported bioactivity.. Human vascular endothelial cells were stimulated with either oxidized LDL (oxLDL) or cluster of differentiation 40 ligand (CD40L) and cotreated with cyanidin-3-glucoside and 11 of its recently identified metabolites, at 0.1, 1, and 10 μM concentrations. Protein and gene expression of IL-6 and VCAM-1 was quantified by ELISA and RT-qPCR. In oxLDL-stimulated cells the parent anthocyanin had no effect on IL-6 production, whereas numerous anthocyanin metabolites significantly reduced IL-6 protein levels; phase II conjugates of protocatechuic acid produced the greatest effects (>75% reduction, p ≤ 0.05). In CD40L-stimulated cells the anthocyanin and its phase II metabolites reduced IL-6 protein production, where protocatechuic acid-4-sulfate induced the greatest reduction (>96% reduction, p ≤ 0.03). Similarly, the anthocyanin and its metabolites reduced VCAM-1 protein production, with ferulic acid producing the greatest effect (>65% reduction, p ≤ 0.04).. These novel data provide evidence to suggest that anthocyanin metabolites are bioactive at physiologically relevant concentrations and have the potential to modulate cardiovascular disease progression by altering the expression of inflammatory mediators.

Topics: Anthocyanins; CD40 Ligand; Coumaric Acids; Endothelial Cells; Gene Expression; Glucosides; Glucuronides; Human Umbilical Vein Endothelial Cells; Humans; Hydroxybenzoates; Interleukin-6; Lipoproteins, LDL; RNA, Messenger; Vascular Cell Adhesion Molecule-1

We and others have demonstrated that anthocyanins have antiatherogenic capability. Because intact anthocyanins are absorbed very poorly, the low level of circulating parent anthocyanins may not fully account for their beneficial effect. We found recently that protocatechuic acid (PCA), a metabolite of cyanidin-3 to 0-β-glucoside (Cy-3-G), has a remarkable antiatherogenic effect.. To investigate whether mouse gut microbiota metabolizes Cy-3-G into PCA and to determine whether and how PCA contributes to the antiatherogenic potency of its precursor, Cy-3-G.. PCA was determined as a gut microbiota metabolite of Cy-3-G in ApoE(-/-) mice, verified by the utilization of antibiotics to eliminate gut microbiota and further microbiota acquisition. PCA but not Cy-3-G at physiologically reachable concentrations promoted cholesterol efflux from macrophages and macrophage ABCA1 and ABCG1 expression. By conducting a miRNA microarray screening, we revealed that expression of miRNA-10b in macrophages can be reduced by PCA. Functional analyses demonstrated that miRNA-10b directly represses ABCA1 and ABCG1 and negatively regulates cholesterol efflux from murine- and human-derived macrophages. Further in vitro and ex vivo analyses verified that PCA accelerates macrophage cholesterol efflux, correlating with the regulation of miRNA-10b-ABCA1/ABCG1 cascade, whereas Cy-3-G consumption promoted macrophage RCT and regressed atherosclerotic lesion in a gut microbiotaendependent manner.. PCA, as the gut microbiota metabolite of Cy-3-G, exerts the antiatherogenic effect partially through this newly defined miRNA-10b-ABCA1/ABCG1-cholesterol efflux signaling cascade. Thus, gut microbiota is a potential novel target for atherosclerosis prevention and treatment.

Topics: Animals; Anthocyanins; Apolipoproteins E; Atherosclerosis; ATP Binding Cassette Transporter 1; ATP Binding Cassette Transporter, Subfamily G, Member 1; ATP-Binding Cassette Transporters; Biological Transport; Cells, Cultured; Cholesterol; Glucosides; HEK293 Cells; Humans; Hydroxybenzoates; Intestinal Absorption; Intestines; Lipoproteins; Macrophages, Peritoneal; Metagenome; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; MicroRNAs

Current research indicates that anthocyanins are primarily degraded to form phenolic acid products. However, no studies have yet demonstrated the metabolic conjugation of these anthocyanin-derived phenolic acids in humans.. Within the present study, a simulated gastrointestinal digestion model was used to evaluate the potential degradation of anthocyanins post-consumption. Subsequently, cyanidin (Cy) and pelargonidin and their degradation products, protocatechuic acid and 4-hydroxybenzoic acid, were incubated in the presence of human liver microsomes to assess their potential to form hepatic glucuronide conjugates. For structural conformation, phenolic glucuronides were chemically synthesised and compared to the microsomal metabolites. During the simulated gastric digestion, anthocyanin glycosides (200 μM) remained stable however their aglycone derivatives were significantly degraded (20% loss), while during subsequent pancreatic/intestinal digestion only pelargonidin-3-glucoside remained stable while cyanidin-3-glucoside (30% loss) and Cy and pelagonidin aglycones were significantly degraded (100% loss, respectively). Following microsomal metabolism, pelargonidin formed 4-hydroxybenzoic acid, which was further metabolised (65%) to form two additional glucuronide conjugates, while Cy formed protocatechuic acid, which was further metabolised (43%) to form three glucuronide conjugates.. We propose that following ingestion, anthocyanins may be found in the systemic circulation as free or conjugated phenolic acids, which should be a focus of future dietary interventions.

Topics: Analysis of Variance; Anthocyanins; Chromatography, High Pressure Liquid; Digestion; Glucosides; Glucuronides; Humans; Hydroxybenzoates; Intestinal Mucosa; Male; Microsomes, Liver; Parabens

Polyphenols, including anthocyanins, from various plant foods are effective in reducing the severity of atherosclerosis in animal and human studies. Due to the poor understanding of the bioavailability of anthocyanins, the potential antiatherogenic mechanisms underlying the action remain largely unknown. Herein, we found that oral gavage of cyanidin-3-O-β-glucoside (Cy-3-G) could be transformed into protocatechuic acid (PCA), and the plasma maximal levels of Cy-3-G were 3.7-fold lower than that of PCA in the apolipoprotein E (ApoE)-deficient mice. Subsequently, we observed that PCA treatment has a higher capacity than Cy-3-G treatment in decreasing CC chemokine receptor 2 (CCR2) expression in the mouse peripheral blood monocytes (PBMs), along with reducing the mouse PBMs chemokine toward CC ligand-2 (CCL2) in a Boyden chamber. Interesting, in the ApoE-deficient mouse model, orally gavaged with Cy-3-G has a higher ability than gavaged with PCA to reduce CCR2 expression in PBMs. PBMs deprived from the Cy-3-G-treated ApoE-deficient mice have a lower ability than those from PCA-treated animals to migrate toward CCL2. Furthermore, as compared with the PCA group, Cy-3-G treatment more efficiently reduced thioglycollate-induced macrophage infiltration into the abdominal cavity. Thus, we suggest that Cy-3-G may reduce the monocyte infiltration in mice via down-regulation of CCR2 expression in monocytes, at least in part, with the aid of its metabolite PCA. These above data imply that the anti-monocyte/macrophage infiltration property of Cy-3-G and its metabolite PCA may be an important antiatherogenic mechanism for anthocyanins.

Topics: Abdominal Cavity; Administration, Oral; Animals; Anthocyanins; Apolipoproteins E; Chemotaxis, Leukocyte; Down-Regulation; Glucosides; Hydroxybenzoates; Macrophages; Mice; Mice, Knockout; Monocytes; Receptors, CCR2

Insulin resistance (IR) represents an independent risk factor for metabolic, cardiovascular, and neoplastic disorders. Preventing/attenuating IR is a major objective to be reached to preserve population health. Because many insulin-sensitizing drugs have shown unwanted side effects, active harmless compounds are sought after. Dietary anthocyanins have been demonstrated to ameliorate hyperglycemia and insulin sensitivity. This study aimed at investigating whether cyanidin-3-O-β-glucoside (C3G) and its metabolite protocatechuic acid (PCA) might have a role in glucose transport activation in human omental adipocytes and 3T3-L1 cells.. In cells treated with 50 µmol/L C3G and 100 µmol/L PCA, [(3)H]-2-deoxyglucose uptake, GLUT4 translocation by immunoblotting, adiponectin secretion, and peroxisome proliferator-activated receptor-γ (PPARγ) activation by enzyme-linked immunosorbent assay kits were evaluated. Parallel experiments were carried out in murine adipocyte 3T3-L1. To define the role of PPARγ in modulating polyphenol effects, small interfering RNA technique and PPARγ antagonist were used to inhibit transcription factor activity.. C3G and PCA increased adipocyte glucose uptake (P < 0.05) and GLUT4 membrane translocation (P < 0.01). Significant increases (P < 0.05) in nuclear PPARγ activity, as well as in adiponectin and GLUT4 expressions (P < 0.01), were also shown. It is interesting that PPARγ inhibition counteracted the polyphenol-induced adiponectin and GLUT4 upregulations, suggesting a direct involvement of PPARγ in this process.. Our study provides evidence that C3G and PCA might exert insulin-like activities by PPARγ activation, evidencing a causal relationship between this transcription factor and adiponectin and GLUT4 upregulation. Dietary polyphenols could be included in the preventive/therapeutic armory against pathological conditions associated with IR.

Topics: 3T3-L1 Cells; Adipocytes; Adiponectin; Animals; Anthocyanins; Cells, Cultured; Gene Expression; Glucosides; Humans; Hydroxybenzoates; Insulin; Mice; Omentum; PPAR gamma

The anti-inflammatory effects of cyanidin-3-O-beta-D-glycoside (C3G), a major constituent of black rice (BR), and its metabolites, cyanidin and protocatechuic acid (PA), were assessed in lipopolysaccharide (LPS)-induced RAW 264.7 cells and carrageenan-induced inflammation in air pouches in BALB/c mice. BR, C3G and its metabolites suppressed the production of the proinflammatory cytokines, TNF-alpha and IL-1 beta, and the inflammatory mediators, NO and prostaglandin E2 (PGE2), as well as the gene expression of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in RAW 264.7 cells. These agents also inhibited the phosphorylation of I kappaB-alpha, the nuclear translocation of NF-kappaB, and the activation of mitogen-activated protein kinases. Furthermore, these agents significantly inhibited the leukocyte number and the levels of TNF-alpha, PGE2, and protein in the exudates of the air pouch in carrageenan-treated mice, as well as COX-2 expression and NF-kappaB activation. Among the test agents, PA most potently inhibited these inflammatory mediators in vivo and in vitro. Based on these findings, if BR is orally administered, its main constituent, C3G, may be metabolized to cyanidin and/or PA, which express potent anti-inflammatory effects by regulating NF-kappaB and MAPK activation.

Topics: Animals; Anthocyanins; Anti-Inflammatory Agents; Carrageenan; Cell Line; Cyclooxygenase 2; Cytokines; Glucosides; Hydroxybenzoates; Inflammation Mediators; Lipopolysaccharides; Macrophages; Male; MAP Kinase Signaling System; Mice; NF-kappa B; Oryza

Black-colored rice (BCR), the main constituent of which is cyanidin-3-O-beta-D-glucoside (C3G), exhibits an anti-allergic effect, and orally administered C3G is mainly metabolized to protocatechuic acid in rats. Therefore, to understand the relationship between the metabolism of C3G and its pharmacological effect, we isolated C3G from BCR, anaerobically incubated it with fecal microflora, investigated its metabolite(s) by LC-MS/MS, and measured the antiscratching behavioral effects of C3G and its metabolites. C3G was metabolized to protocatechuic acid via cyanidin. Protocatechuic acid and cyanidin were identified as the metabolites. The activities transforming C3G to protocatechuic acid and cyanidin were 28.2 +/- 11.7 and 21.8 +/- 5.2 nmol/h/mg fecal microflora, respectively. C3G and its metabolites showed inhibitory effects against histamine- or compound 48/80-induced scratching behaviors in mice. C3G more potently inhibited scratching behaviors following oral administration than following intraperitoneal administration. However, protocatechuic acid and cyanidin showed more potent inhibition when administered intraperitoneally than when administered orally. These metabolites also inhibited the expression of allergic cytokines, IL-4 and TNF-alpha, and the activation of their transcription factor, NF-kappaB, in RBL-2H3 cells stimulated with IgE-antigen. These findings suggest that C3G-rich BCR may be a beneficial food for diseases involving scratching behaviors, such as chronic dermatitis, rhinitis, and psoriasis.

Topics: Animals; Anthocyanins; Anti-Allergic Agents; Cell Degranulation; Cell Line, Tumor; Dose-Response Relationship, Drug; Glucosides; Humans; Hydroxybenzoates; Interleukin-4; Male; Mice; Mice, Inbred BALB C; Mice, Inbred ICR; NF-kappa B; Oryza; Pruritus; Rats; Seeds; Tumor Necrosis Factor-alpha

Recent in vivo studies have highlighted an important role for the neuroprotective actions of dietary anthocyanins. However, one consistent result of these studies is that the systemic bioavailability of anthocyanins, including cyanidin 3-O-glucopyranoside (Cy-3G), is very poor. Cy-3G has been demonstrated to be highly instable at physiological pH, so its in vivo metabolites, such as the aglycon cyanidin (Cy) and protocatechuic acid (PA), may be responsible for both the antioxidant activitiy and the neuroprotective effects observed in vivo. Therefore, we investigated the protective effects of Cy-3G, Cy and PA against H(2)O(2)-induced oxidative stress in a human neuronal cell line (SH-SY5Y). We determined their ability to counteract reactive oxygen species (ROS) formation and to inhibit apoptosis in terms of mitochondrial functioning loss and DNA fragmentation induced by H(2)O(2). We demonstrated that pretreatment of SH-SY5Y cells with Cy-3G, Cy and PA inhibits H(2)O(2)-induced ROS formation at different cellular levels: Cy-3G at membrane level, PA at cytosolic level and Cy at both membrane and cytosolic levels. In addition, Cy showed a higher antioxidant activity at membrane and cytosolic level than Cy-3G and PA, respectively. Interestingly, both Cy and PA, but not Cy-3G, could inhibit H(2)O(2)-induced apoptotic events, such as mitochondrial functioning loss and DNA fragmentation. These results suggest that Cy and PA may be considered as neuroprotective molecules and may play an important role in brain health promotion. These in vitro findings should encourage further research in animal models of neurological diseases to explore the potential neuroprotective effects of compounds generated during in vivo metabolism of anthocyanins.

Topics: Anthocyanins; Antioxidants; Apoptosis; Brain Diseases; Cell Line, Tumor; Cytosol; Drug Evaluation, Preclinical; Humans; Hydroxybenzoates; Mitochondria; Nerve Degeneration; Neurons; Neuroprotective Agents; Oxidative Stress; Reactive Oxygen Species

Rice has been one of the most important grains. While polished white rice is favored, colored strains of rice, red, or black, have been maintained for religious purposes in Japan. We studied whether feeding of unpolished colored rice instead of white rice ameliorates oxidative renal tubular damage in rats induced by ferric nitrilotriacetate. Whereas renal lipid peroxidation was exacerbated in white rice-fed group in comparison with standard chow group, this exacerbation was not observed in red or black rice-fed groups. These changes were dependent on the proportion of colored rice to standard chow in the diet. Cyanidin 3-O-beta-D-glucoside was detectable neither in the serum nor kidney after one week of colored rice diet, but serum protocatechuic acid was significantly increased after black rice diet. There was a generalized decrease in the renal glutathione peroxidase activity in rice diet groups. Renal enzymatic activities of superoxide dismutase, glutathione S-transferase and NAD(P)H quinone reductase were not associated with the levels of lipid peroxidation. However, renal catalase activity was significantly increased in black rice-fed groups. These may partly explain the antioxidative effect. Furthermore, colored strains of rice are rich in proteins. Thus, our data warrants further investigation of the antioxidative effect of colored rice.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Anthocyanins; Body Weight; Carcinogens; Catalase; Deoxyguanosine; Diet; Ferric Compounds; Glucosides; Glutathione Peroxidase; Glutathione Transferase; Hydrogen Peroxide; Hydroxybenzoates; Immunoenzyme Techniques; Iron; Kidney Diseases; Kidney Tubules, Proximal; Lipid Peroxidation; Male; Nitrilotriacetic Acid; Oryza; Phytotherapy; Rats; Rats, Wistar; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances