Purple corn anthocyanins retard diabetes-associated glomerulosclerosis in mesangial cells and db/db mice

Efficacy and Tolerability of a Food Supplement Based on Zea mays L., Gymnema sylvestre (Retz.) R.br.ex Sm, Zinc and Chromium for the Maintenance of Normal Carbohydrate Metabolism: A Monocentric, Randomized, Double-Blind, Placebo-Controlled Clinical Trial

A study on 81 individuals (18-75 years old) with mildly impaired fasting blood glucose (FBG) concentrations (98-125 mg/dL) was undertaken to investigate the tolerability of a food supplement (FS) based on Zea mays and Gymnema sylvestre extracts, zinc, and chromium and its efficacy on glucose and lipid metabolism. The subjects were randomized into three groups (27 in each group) and supplemented with one or two tablet(s)/day of FS (groups 1 and 2, respectively), or two tablets/day of placebo (group 3). Blood sampling was carried out at baseline (t0) and after a 3-month treatment (t1), and biochemical parameters associated with glucose and lipid metabolism and kidney and liver toxicity were evaluated. Compared to the placebo, FBG and glycated haemoglobin (HbA1c) were significantly (p < 0.001) reduced in group 1 subjects. In contrast, at the doses of one and two tablet(s)/day, the FS exerted no effect on the other parameters examined. We conclude that in subjects with slightly impaired FBG, ingestion of a FS based on Z. mays and G. sylvestre extracts, zinc, and chromium over 3 months lowers FBG and modulates glucose homeostasis by improving glucose metabolism. These beneficial effects occur in the absence of biochemical evidence of kidney and liver toxicity.

Anthocyanins' effects on diabetes mellitus and islet transplantation

The incidence of diabetes mellitus is dramatically increasing every year, causing a huge global burden. Moreover, existing anti-diabetic drugs inevitably bring adverse reactions, and the application of islet transplantation is often limited by the damage caused by oxidative stress after transplantation. Thus, new approaches are needed to combat the growing burden of diabetes mellitus. Anthocyanins are of great nutritional interest and have been documented that have beneficial effects on chronic diseases, including diabetes mellitus. Here, we describe the health effects of anthocyanins on diabetes mellitus and islet transplantation. Epidemiological studies demonstrated that moderate intake of anthocyanins leading to a reduction in risk of diabetes mellitus. Numerous experiments both animal and clinical studies also showed positive effects of anthocyanins on prevention and treatment of diabetes and diabetic complications. These effects of anthocyanins may be related to mechanisms of improving glucose and lipid metabolism and insulin resistance, antioxidant, and anti-inflammatory activities. In addition, damage and function of pancreatic islets after transplantation are also improved by anthocyanins. These findings suggest that daily intake of anthocyanins may not only improve nutritional metabolism in healthy individuals to prevent from diabetes, but also as a supplementary treatment of diabetes mellitus and islet transplantation. Thus, more evidence is needed to better understand the potential health benefits of anthocyanins.

Anthocyanins: Potential Therapeutic Approaches towards Obesity and Diabetes Mellitus Type 2

Overweight and obesity are present in about three-quarters of the adult population in Mexico. The inflammatory mechanisms subjacent to visceral white adipose tissue are accountable for the initiation and development of cardiometabolic alterations, including type 2 diabetes. Lifestyle changes are pillars within its therapeutics and, thus, current dietary modifications should include not only hypocaloric prescriptions with balanced macronutrient intake, preferably by increasing the amount of whole grains, fruits, vegetables, nuts and legumes, but in concomitance, bioactive substances, such as anthocyanins, have been correlated with lower incidence of this disease.

Does Plant Breeding for Antioxidant-Rich Foods Have an Impact on Human Health?

Given the general beneficial effects of antioxidants-rich foods on human health and disease prevention, there is a continuous interest in plant secondary metabolites conferring attractive colors to fruits and grains and responsible, together with others, for nutraceutical properties. Cereals and Solanaceae are important components of the human diet, thus, they are the main targets for functional food development by exploitation of genetic resources and metabolic engineering. In this review, we focus on the impact of antioxidants-rich cereal and Solanaceae derived foods on human health by analyzing natural biodiversity and biotechnological strategies aiming at increasing the antioxidant level of grains and fruits, the impact of agronomic practices and food processing on antioxidant properties combined with a focus on the current state of pre-clinical and clinical studies. Despite the strong evidence in in vitro and animal studies supporting the beneficial effects of antioxidants-rich diets in preventing diseases, clinical studies are still not sufficient to prove the impact of antioxidant rich cereal and Solanaceae derived foods on human

Nephroprotective Effects of Synthetic Flavonoid Hidrosmin in Experimental Diabetic Nephropathy

Diabetes mellitus (DM) is a high-impact disease commonly characterized by hyperglycemia, inflammation, and oxidative stress. Diabetic nephropathy (DN) is a common diabetic microvascular complication and the leading cause of chronic kidney disease worldwide. This study investigates the protective effects of the synthetic flavonoid hidrosmin (5-O-(beta-hydroxyethyl) diosmin) in experimental DN induced by streptozotocin injection in apolipoprotein E deficient mice. Oral administration of hidrosmin (300 mg/kg/day, n = 11) to diabetic mice for 7 weeks markedly reduced albuminuria (albumin-to-creatinine ratio: 47 ± 11% vs. control) and ameliorated renal pathological damage and expression of kidney injury markers. Kidneys of hidrosmin-treated mice exhibited lower content of macrophages and T cells, reduced expression of cytokines and chemokines, and attenuated inflammatory signaling pathways. Hidrosmin treatment improved the redox balance by reducing prooxidant enzymes and enhancing antioxidant genes, and also decreased senescence markers in diabetic kidneys. In vitro, hidrosmin dose-dependently reduced the expression of inflammatory and oxidative genes in tubuloepithelial cells exposed to either high-glucose or cytokines, with no evidence of cytotoxicity at effective concentrations. In conclusion, the synthetic flavonoid hidrosmin exerts a beneficial effect against DN by reducing inflammation, oxidative stress, and senescence pathways. Hidrosmin could have a potential role as a coadjutant therapy for the chronic complications of DM.

Anthocyanins: From Mechanisms of Regulation in Plants to Health Benefits in Foods

Anthocyanins represent the major red, purple, and blue pigments in many flowers, fruits, vegetables, and cereals. They are also recognized as important health-promoting components in the human diet with protective effects against many chronic diseases, including cardiovascular diseases, obesity, and cancer. Anthocyanin biosynthesis has been studied extensively, and both biosynthetic and key regulatory genes have been isolated in many plant species. Here, we will provide an overview of recent progress in understanding the anthocyanin biosynthetic pathway in plants, focusing on the transcription factors controlling activation or repression of anthocyanin accumulation in cereals and fruits of different plant species, with special emphasis on the differences in molecular mechanisms between monocot and dicot plants. Recently, new insight into the transcriptional regulation of the anthocyanin biosynthesis, including positive and negative feedback control as well as epigenetic and post-translational regulation of MYB-bHLH-WD40 complexes, has been gained. We will consider how knowledge of regulatory mechanisms has helped to produce anthocyanin-enriched foods through conventional breeding and metabolic engineering. Additionally, we will briefly discuss the biological activities of anthocyanins as components of the human diet and recent findings demonstrating the important health benefits of anthocyanin-rich foods against chronic diseases.

Therapeutic and delivery strategies of phytoconstituents for renal fibrosis

Chronic kidney disease (CKD) is one of the most common diseases endangering human health and life. By 2030, 14 per 100,000 people may die from CKD. Renal fibrosis (RF) is an important intermediate link and the final pathological change during CKD progression to the terminal stage. Therefore, identifying safe and effective treatment methods for RF has become an important goal. In 2018, the World Health Organization introduced traditional Chinese medicine into its effective global medical program. Various phytoconstituents that affect the RF process have been extracted from different plants. Here, we review the potential therapeutic capabilities of active phytoconstituents in RF treatment and discuss how phytoconstituents can be structurally modified or combined with other ingredients to enhance efficiency and reduce toxicity. We also summarize phytoconstituent delivery strategies to overcome renal barriers and improve bioavailability and targeting.

Chondroprotective effects of purple corn anthocyanins on advanced glycation end products induction through suppression of NF-κB and MAPK signaling

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.

Genetic characterization and association mapping in near-isogenic lines of waxy maize using seed characteristics and SSR markers

BACKGROUND

Association mapping has been advocated as the method of choice for identifying loci involved in the inheritance of complex traits in crop species. This method involves identifying markers with significant differences in allele frequency between individuals with a phenotype of interest and a set of unrelated control individuals.

OBJECTIVE

The purpose of our study is not only to investigate the genetic diversity and relationships of the basic molecular markers of near-isogenic lines (NILs) of waxy maize, but it is also to identify molecular markers related to interesting seed characteristics including 4 seed quantity traits and 4 seed phenotypic traits using association analysis with population structure.

METHODS

We performed association mapping of 200 SSR markers and 8 seed characteristics among 10 NILs of waxy maize and two parental lines (HW3, HW9) (recurrent parent) of "Mibaek 2" variety.

RESULTS

In population structure and cluster analysis, the 10 NILs and two parental lines were divided into two groups. Seven inbred lines, including HW3, were assigned to Group I. Group II contained 5 inbred lines, including HW9. In addition, we found that 32 SSR markers associate with 8 seed characteristics in 10 NILs. In particular, five SSR markers (umc1986, umc1747, umc2275, phi078, umc1366) were together associated with more than one seed characteristics such as EL, 100 KW, SCC, R, L*, and V.

CONCLUSION

This study demonstrated the utility of SSR analysis for studying GD, population structure, and association mapping in 10 NILs and two parental lines (HW3, HW9) of "Mibaek 2" variety.

Eucalyptol Ameliorates Dysfunction of Actin Cytoskeleton Formation and Focal Adhesion Assembly in Glucose-Loaded Podocytes and Diabetic Kidney

SCOPE

Podocytes are a component of glomerular filtration barrier with interdigitating foot processes. The podocyte function depends on the dynamics of actin cytoskeletal and focal adhesion crucial for foot process structure. This study investigates the renoprotective effects of eucalyptol on the F-actin cytoskeleton formation and focal adhesion assembly in glucose-loaded podocytes and diabetic kidneys.

METHODS AND RESULTS

Eucalyptol at 1-20 µm reverses the reduction of cellular level of F-actin, ezrin, cortactin, and Arp2/3 in 33 mm glucose-loaded mouse podocytes, and oral administration of 10 mg kg^-1 eucalyptol elevates tissue levels of actin cytoskeletal proteins reduced in db/db mouse kidneys. Eucalyptol inhibits podocyte morphological changes, showing F-actin cytoskeleton formation in cortical regions and agminated F-actin along the cell periphery. Eucalyptol induces focal adhesion proteins of paxillin, vinculin, talin1, FAK, and Src in glucose-exposed podocytes and diabetic kidneys. Additionally, GTP-binding Rac1, Cdc42, Rho A, and ROCK are upregulated in glucose-stimulated podocytes and diabetic kidneys, which is attenuated by supplying eucalyptol. Rho A gene depletion partially diminishes GSK3β induction of podocytes by glucose.

CONCLUSION

Eucalyptol ameliorates F-actin cytoskeleton formation and focal adhesion assembly through blockade of the Rho signaling pathway, entailing partial involvement of GSK3β, which may inhibit barrier dysfunction of podocytes and resultant proteinuria.

Comparative transcriptome analysis reveals differentially expressed genes related to the tissue-specific accumulation of anthocyanins in pericarp and aleurone layer for maize

Purple corn is a rich source of anthocyanins. In the experiment, two anthocyanins-enriched purple corn lines Ha0414 and Ha6130 were identified. The anthocyanins were respectively accumulated in the pericarp of Ha0414 and the aleurone layer of Ha6130 with different composition and content. Transcriptome analysis of the two tissues in both lines identified 16 and 14 differentially expressed genes belonging to anthocyanin metabolism pathway in pericarp and the aleurone layer, individually. Of these genes, two genes encoding 2-oxoglutarate (2OG) and Fe (II)-dependent oxygenase superfamily proteins, and one gene annotated as UDP-glycosyltransferase superfamily protein exhibited increased transcript abundance in both the colored pericarp and aleurone layer. Otherwise, one gene annotated as flavonoid 3′, 5′-hydroxylase, and another gene encoding flavonoid 3′-monooxygenase displayed increased transcript abundance in the aleurone layer of Ha6130. Moreover, 36 transcription factors were identified with increased transcript abundance in the pericarp of Ha0414, such as bHLH transcription factors, WRKY transcription factors, and HB transcription factors. And 79 transcription factors were isolated with an increased expression level in the aleurone layer of Ha6130, including MYB transcription factors, MYB-related transcription factors, and bHLH transcription factors. These genes expression may result in the tissue-specific accumulation of anthocyanins in pericarp and aleurone layer.

Dietary Chrysin Suppresses Formation of Actin Cytoskeleton and Focal Adhesion in AGE-Exposed Mesangial Cells and Diabetic Kidney: Role of Autophagy

Advanced glycation end products (AGE) play a causative role in the development of aberrant phenotypes of intraglomerular mesangial cells, contributing to acute/chronic glomerulonephritis. The aim of this study was to explore mechanistic effects of the flavonoid chrysin present in bee propolis and herbs on actin dynamics, focal adhesion, and the migration of AGE-exposed mesangial cells. The in vitro study cultured human mesangial cells exposed to 33 mM glucose and 100 μg/mL AGE-bovine serum albumin (AGE-BSA) for up to 5 days in the absence and presence of 1⁻20 μM chrysin. The in vivo study employed db/db mice orally administrated for 10 weeks with 10 mg/kg chrysin. The presence of ≥10 μM chrysin attenuated mesangial F-actin induction and bundle formation enhanced by AGE. Chrysin reduced the mesangial induction of α-smooth muscle actin (α-SMA) by glucose, and diminished the tissue α-SMA level in diabetic kidneys, indicating its blockade of mesangial proliferation. The treatment of chrysin inhibited the activation of vinculin and paxillin and the induction of cortactin, ARP2/3, fascin-1, and Ena/VASP-like protein in AGE-exposed mesangial cells. Oral administration of chrysin diminished tissue levels of cortactin and fascin-1 elevated in diabetic mouse kidneys. Mesangial cell motility was enhanced by AGE, which was markedly attenuated by adding chrysin to cells. On the other hand, chrysin dampened the induction of autophagy-related genes of beclin-1, LC3 I/II, Atg3, and Atg7 in mesangial cells exposed to AGE and in diabetic kidneys. Furthermore, chrysin reduced the mTOR activation in AGE-exposed mesangial cells and diabetic kidneys. The induction of mesangial F-actin, cortactin, and fascin-1 by AGE was deterred by the inhibition of autophagy and mTOR. Thus, chrysin may encumber diabetes-associated formation of actin bundling and focal adhesion and mesangial cell motility through disturbing autophagy and mTOR pathway.

Chrysin Inhibits Advanced Glycation End Products-Induced Kidney Fibrosis in Renal Mesangial Cells and Diabetic Kidneys

Advanced glycation end products (AGEs) play a causative role in the development of diabetic nephropathy via induction of matrix protein deposition in kidneys. This study investigated inhibitory effects of chrysin, present in bee propolis and herbs, on glomerulosclerosis in db/db mice and AGEs-exposed renal mesangial cells. The in vivo study explored the demoting effects of 10 mg/kg chrysin on glomerular fibrosis in a type 2 diabetic model. Oral supplementation of chrysin inhibited the collagen fiber accumulation and &alpha;-smooth muscle actin (&alpha;-SMA) induction in periodic acid schiff-positive renal tissues of db/db mice. Moreover, treating db/db mice with chrysin diminished the level of AGEs increased in diabetic glomeruli. The in vitro study employed human mesangial cells exposed to 100 &mu;g/mL AGE-BSA for 72 h in the presence of 1⁻20 &mu;M chrysin. Glucose increased mesangial AGE production via induction of receptor for AGEs. Chrysin suppressed the induction of collagens, &alpha;-SMA, fibroblast-specific protein-1 and matrix metalloproteinases enhanced by AGE-bovine serum albumin. Furthermore, chrysin blunted transforming growth factor-&beta;1 induction and Smad 2/3 activation in AGEs-exposed mesangial cells. These results demonstrate that chrysin attenuated accumulation of myofibroblast-like cells and matrix proteins in AGEs-laden diabetic glomeruli. Therefore, chrysin may be a potential renoprotective agent targeting glucose-mediated AGEs-associated glomerulosclerosis and fibrosis.

Phenolic Composition and Evaluation of the Antimicrobial Activity of Free and Bound Phenolic Fractions from a Peruvian Purple Corn (Zea mays L.) Accession

Beneficial effects on overall gut health by phenolic bioactives-rich foods are potentially due to their modulation of probiotic gut bacteria and antimicrobial activity against pathogenic bacteria. Based on this rationale, the effect of the free and bound phenolic fractions from a Peruvian purple corn accession AREQ-084 on probiotic lactic acid bacteria such as Lactobacillus helveticus and Bifidobacterium longum and the gastric cancer-related pathogen Helicobacter pylori was evaluated. The free and bound phenolic composition was also determined by ultra-performance liquid chromatography. Anthocyanins were the major phenolic compounds (310.04 mg cyanidin-3-glucoside equivalents/100 g dry weight, DW) in the free phenolic fraction along with hydroxycinnamic acids such as p-coumaric acid derivatives, followed by caffeic and ferulic acid derivatives. The bound phenolic form had only hydroxycinnamic acids such as ferulic acid, p-coumaric acid, and a ferulic acid derivative with ferulic acid being the major phenolic compound (156.30 mg/100 g DW). These phenolic compounds were compatible with beneficial probiotic lactic acid bacteria such as L. helveticus and B. longum as these bacteria were not inhibited by the free and bound phenolic fractions at 10 to 50 mg/mL and 10 mg/mL of sample doses, respectively. However, the pathogenic H. pylori was also not inhibited by both purple corn phenolic forms at same above sample doses. This study provides the preliminary base for the characterization of phenolic compounds of Peruvian purple corn biodiversity and its potential health benefits relevant to improving human gut health.

PRACTICAL APPLICATION

This study provides insights that Peruvian purple corn accession AREQ-084 can be targeted as a potential source of health-relevant phenolic compounds such as anthocyanins along with hydroxycinnamic acids linked to its dietary fiber fraction. Additionally, these phenolic fractions did not affect the gut health associated beneficial bacteria nor the pathogenic H. pylori. Purple corn can be targeted for design of probiotic functional foods integrated with their anthocyanin linked-coloring properties.

Daily Intake of Grape Powder Prevents the Progression of Kidney Disease in Obese Type 2 Diabetic ZSF1 Rats

Individuals living with metabolic syndrome (MetS) such as diabetes and obesity are at high risk for developing chronic kidney disease (CKD). This study investigated the beneficial effect of whole grape powder (WGP) diet on MetS-associated CKD. Obese diabetic ZSF1 rats, a kidney disease model with MetS, were fed WGP (5%, w/w) diet for six months. Kidney disease was determined using blood and urine chemical analyses, and histology. When compared to Vehicle controls, WGP intake did not change the rat bodyweight, but lowered their kidney, liver and spleen weight, which were in parallel with the lower serum glucose and the higher albumin or albumin/globin ratio. More importantly, WGP intake improved the renal function as urination and proteinuria decreased, or it prevented kidney tissue damage in these diabetic rats. The renal protection of WGP diet was associated with up-regulation of antioxidants (Dhcr24, Gstk1, Prdx2, Sod2, Gpx1 and Gpx4) and downregulation of Txnip (for ROS production) in the kidneys. Furthermore, addition of grape extract reduced H₂O₂-induced cell death of cultured podocytes. In conclusion, daily intake of WGP reduces the progression of kidney disease in obese diabetic rats, suggesting a protective function of antioxidant-rich grape diet against CKD in the setting of MetS.

Health Benefits of Purple Corn (Zea mays L.) Phenolic Compounds

Purple corn (Zea mays L.), a grain with one of the deepest shades in the plant kingdom, has caught the attention of the food industry as it could serve as a source for alternatives to synthetic colorants. Also being rich in phenolic compounds with potential health-promoting properties, purple corn is becoming a rising star in the novel ingredients market. Although having been widely advertised as a "healthy" food, the available information on purple corn health benefits has not yet been well reviewed and summarized. In this review, we present compositional information focused on the potential functional phenolic compounds correlated to health-promoting effects. Studies evaluating potential health-benefitting properties, including in vitro tests, cell models, animal and human trials, are also discussed. This paper emphasizes research using purple corn, or its extracts, but some other plant sources with similar phenolic composition to purple corn are also mentioned. Dosage and toxicity of purple corn studies are also reviewed. Purple corn phenolic compounds have been shown in numerous studies to have potent antioxidant, anti-inflammatory, antimutagenic, anticarcinogenic, and anti-angiogenesis properties. They were also found to ameliorate lifestyle diseases, such as obesity, diabetes, hyperglycemia, hypertension, and cardiovascular diseases, based on their strong antioxidant power involving biochemical regulation amelioration. With promising evidence from cell and animal studies, this rich source of health-promoting compounds warrants additional attention to better understand its potential contributions to human health.

Cooked common beans (Phaseolus vulgaris L.) modulate renal genes in streptozotocin-induced diabetic rats

Food consumption with different bioactive compounds could reduce the risk of diabetic complications. This study was designed to evaluate the effect of cooked common beans on differentially expressed genes in whole kidney homogenates of streptozotocin-induced diabetic rats. After 4weeks of treatment with a cooked bean supplemented (10%) diet, animals fed with Flor de Mayo bean (FMB) exerted the greatest protective effect, since they presented the lowest blood glucose levels, consistent with an increase in blood insulin levels, a decrease in urine albumin and urea levels and an increase in creatinine clearance (P≤.05). Regarding the gene expression of kidneys evaluated using expressed sequence tag, consumption of cooked beans improved the expression of Glu1, Cps1, Ipmk, Cacna1c, Camk1, Pdhb, Ptbp3 and Pim1, which are related to the elimination of ammonium groups, the regulation of inflammatory and oxidative response, as well as cell signaling and apoptosis. In addition, the beneficial effects observed were not related to their polyphenolic and saponin profile, suggesting the activity of other bioactive compounds or the synergistic interaction of these compounds. These results suggest that the consumption of cooked common beans (FMB) might be used as an alternative for the regulation of genes related to renal alterations.

Potential Renoprotective Agents through Inhibiting CTGF/CCN2 in Diabetic Nephropathy

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease (ESRD). The development and progression of DN might involve multiple factors. Connective tissue growth factor (CCN2, originally known as CTGF) is the one which plays a pivotal role. Therefore, increasing attention is being paid to CCN2 as a potential therapeutic target for DN. Up to date, there are also many drugs or agents which have been shown for their protective effects against DN via different mechanisms. In this review, we only focus on the potential renoprotective therapeutic agents which can specifically abolish CCN2 expression or nonspecifically inhibit CCN2 expression for retarding the development and progression of DN.

Anthocyanins in corn: a wealth of genes for human health

Different epidemiological and preclinical studies have demonstrated that regular consumption of anthocyanin-rich foods is associated to a reduced risk of chronic diseases, such as cardiovascular diseases, cancer and obesity. However, assigning a health property to anthocyanins or other classes of flavonoids may be limited by the influence of other metabolites of plant-based food consumed in the diet, acting as possible confounding factors. The development of model foods essentially isogenic and nutritionally identical except that in the type and quantity of plant bioactives to be studied represents an important tool in nutritional studies. The extensive knowledge of the regulation of flavonoid pathway in maize can be exploited to obtain 'near-isogenic' model foods, which differ only in the content of specific classes of flavonoids. Being obtainable by breeding strategies, maize model foods can provide functional foods that can be used for both animal feeding studies and human intervention trials for assessing the role of flavonoids or other bioactives in preventing chronic diseases. This review will be focused on recent advances regarding the anthocyanin biosynthesis in maize, the role of anthocyanins from corn in preventing chronic diseases and finally on the breeding activities to produce maize functional foods with increased anthocyanin content.

Anthocyanin-rich purple corn extract inhibit diabetes-associated glomerular angiogenesis

Diabetic nephropathy (DN) is one of the major diabetic complications and the leading cause of end-stage renal disease. Abnormal angiogenesis results in new vessels that are often immature and play a pathological role in DN, contributing to renal fibrosis and disrupting glomerular failure. Purple corn has been utilized as a daily food and exerts disease-preventive activities. This study was designed to investigate whether anthocyanin-rich purple corn extract (PCE) prevented glomerular angiogenesis under hyperglycemic conditions. Human endothelial cells were cultured in conditioned media of mesangial cells exposed to 33 mM high glucose (HG-HRMC-CM). PCE decreased endothelial expression of vascular endothelial growth factor (VEGF) and hypoxia inducible factor (HIF)-1α induced by HG-HRMC-CM. Additionally, PCE attenuated the induction of the endothelial marker of platelet endothelial cell adhesion molecule (PECAM)-1 and integrin β3 enhanced in HG-HRMC-CM. Endothelial tube formation promoted by HG-HRMC-CM was disrupted in the presence of PCE. In the in vivo study employing db/db mice treated with 10 mg/kg PCE for 8 weeks, PCE alleviated glomerular angiogenesis of diabetic kidneys by attenuating the induction of VEGF and HIF-1α. Oral administration of PCE retarded the endothelial proliferation in db/db mouse kidneys, evidenced by its inhibition of the induction of vascular endothelium-cadherin, PECAM-1 and Ki-67. PCE diminished the mesangial and endothelial induction of angiopoietin (Angpt) proteins under hypeglycemic conditions. The induction and activation of VEGF receptor 2 (VEGFR2) were dampened by treating PCE to db/db mice. These results demonstrate that PCE antagonized glomerular angiogenesis due to chronic hyperglycemia and diabetes through disturbing the Angpt-Tie-2 ligand-receptor system linked to renal VEGFR2 signaling pathway. Therefore, PCE may be a potent therapeutic agent targeting abnormal angiogenesis in DN leading to kidney failure.