Antidiabetic and Beta cell-protection activities of purple corn anthocyanins

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.

Genome-wide identification of grape ANS gene family and expression analysis at different fruit coloration stages

BACKGROUND

Anthocyanin synthase (ANS) is the enzyme downstream of the anthocyanins synthesis pathway and the rate-limiting enzyme of the synthesis pathway. It catalyzes the conversion of colorless anthocyanins to anthocyanins and plays an important role in plant color presentation and stress resistance. However, ANS gene is rarely studied in grapes.

RESULTS

In this study, 121 VvANS genes were identified and distributed on 18 chromosomes, VvANS family members were divided into 8 subgroups. Secondary structure prediction showed mainly irregular coils and α-helices, and subcellular localization indicated that VvANS gene family is mainly located in chloroplast, cytoplasm and nucleus. The promoter region of the VvANS gene family contains multiple cis-acting elements that are associated with light, abiotic stress, and hormones. Intraspecific collinearity analysis showed that there were 13 pairs of collinearity between VvANS genes. Interspecific collinearity analysis showed that there was more collinearity between grape, apple and Arabidopsis, but less collinearity between grape and rice. Microarray data analysis showed that VvANS17, VvANS23 and VvANS75 had higher expression levels in flesh and peel, while VvANS25, VvANS64 and VvANS106 had higher expression levels in flower. The results of qRT-PCR analysis showed that VvANS genes were expressed throughout the whole process of fruit coloring, such as VvANS47 and VvANS55 in the green fruit stage, VvANS3, VvANS64 and VvANS90 in the initial fruit color turning stage. The expression levels of VvANS21, VvANS79 and VvANS108 were higher at 50% coloring stage, indicating that these genes play an important role in the fruit coloring process. VvANS4, VvANS66 and VvANS113 had the highest expression levels in the full maturity stage.

CONCLUSIONS

These results indicated that different members of VvANS gene family played a role in different coloring stages, and this study laid a foundation for further research on the function of ANS gene family.

Genome-Wide Identification and Expression Analysis of ANS Family in Strawberry Fruits at Different Coloring Stages

To elucidate the structural characteristics, phylogeny and biological function of anthocyanin synthase (ANS) and its role in anthocyanin synthesis, members of the strawberry ANS gene family were obtained by whole genome retrieval, and their bioinformatic analysis and expression analysis at different developmental stages of fruit were performed. The results showed that the strawberry ANS family consisted of 141 members distributed on 7 chromosomes and could be divided into 4 subfamilies. Secondary structure prediction showed that the members of this family were mainly composed of random curls and α-helices, and were mainly located in chloroplasts, cytoplasm, nuclei and cytoskeletons. The promoter region of the FvANS gene family contains light-responsive elements, abiotic stress responsive elements and hormone responsive elements, etc. Intraspecific collinearity analysis revealed 10 pairs of FvANS genes, and interspecific collinearity analysis revealed more relationships between strawberries and apples, grapes and Arabidopsis, but fewer between strawberries and rice. Chip data analysis showed that FvANS15, FvANS41, FvANS47, FvANS48, FvANS49, FvANS67, FvANS114 and FvANS132 were higher in seed coat tissues and endosperm. FvANS16, FvANS85, FvANS90 and FvANS102 were higher in internal and fleshy tissues. Quantitative real-time PCR (qRT-PCR) showed that the ANS gene was expressed throughout the fruit coloring process. The expression levels of most genes were highest in the 50% coloring stage (S3), such as FvANS16, FvANS19, FvANS31, FvANS43, FvANS73, FvANS78 and FvANS91. The expression levels of FvANS52 were the highest in the green fruit stage (S1), and FvANS39 and FvANS109 were the highest in the 20% coloring stage (S2). These results indicate that different members of the FvANS gene family play a role in different pigmentation stages, with most genes playing a role in the expression level of the rapid accumulation of fruit coloring. This study lays a foundation for further study on the function of ANS gene family.

Anthocyanins in metabolites of purple corn

Purple corn (Zea mays L.) is a special variety of corn, rich in a large amount of anthocyanins and other functional phytochemicals, and has always ranked high in the economic benefits of the corn industry. However, most studies on the stability of agronomic traits and the interaction between genotype and environment in cereal crops focus on yield. In order to further study the accumulation and stability of special anthocyanins in the growth process of purple corn, this review starts with the elucidation of anthocyanins in purple corn, the biosynthesis process and the gene regulation mechanism behind them, points out the influence of anthocyanin metabolism on anthocyanin metabolism, and introduces the influence of environmental factors on anthocyanin accumulation in detail, so as to promote the multi-field production of purple corn, encourage the development of color corn industry and provide new opportunities for corn breeders and growers.

The Potential Roles of Dietary Anthocyanins in Inhibiting Vascular Endothelial Cell Senescence and Preventing Cardiovascular Diseases

Cardiovascular disease (CVD) is a group of diseases affecting the heart and blood vessels and is the leading cause of morbidity and mortality worldwide. Increasingly more evidence has shown that the senescence of vascular endothelial cells is the key to endothelial dysfunction and cardiovascular diseases. Anthocyanin is a type of water-soluble polyphenol pigment and secondary metabolite of plant-based food widely existing in fruits and vegetables. The gut microbiome is involved in the metabolism of anthocyanins and mediates the biological activities of anthocyanins and their metabolites, while anthocyanins also regulate the growth of specific bacteria in the microbiota and promote the proliferation of healthy anaerobic flora. Accumulating studies have shown that anthocyanins have antioxidant, anti-inflammatory, and anti-aging effects. Many animal and in vitro experiments have also proven that anthocyanins have protective effects on cardiovascular-disease-related dysfunction. However, the molecular mechanism of anthocyanin in eliminating aging endothelial cells and preventing cardiovascular diseases is very complex and is not fully understood. In this systematic review, we summarize the metabolism and activities of anthocyanins, as well as their effects on scavenging senescent cells and cardioprotection.

Cyanidin-3-rutinoside stimulated insulin secretion through activation of L-type voltage-dependent Ca2+ channels and the PLC-IP3 pathway in pancreatic β-cells

Cyanidin-3-rutinoside (C3R) is an anthocyanin with anti-diabetic properties found in red-purple fruits. However, the molecular mechanisms of C3R on Ca²⁺-dependent insulin secretion remains unknown. This study aimed to identify C3R's mechanisms of action in pancreatic β-cells. Rat INS-1 cells were used to elucidate the effects of C3R on insulin secretion, intracellular Ca²⁺ signaling, and gene expression. The results showed that C3R at 60, 100, and 300 µM concentrations significantly increased insulin secretion via intracellular Ca²⁺ signaling. The exposure of cells with C3R concentrations up to 100 μM did not affect cell viability. Pretreatment of cells with nimodipine (voltage-dependent Ca²⁺ channel (VDCC) blocker), U73122 (PLC inhibitor), and 2-APB (IP₃ receptor blocker) inhibited the intracellular Ca²⁺ signals by C3R. Interestingly, C3R increased intracellular Ca²⁺ signals and insulin secretion after depletion of endoplasmic reticulum Ca²⁺ stores by thapsigargin. However, insulin secretion was abolished under extracellular Ca²⁺-free conditions. Moreover, C3R upregulated mRNA expression for Glut2 and Kir_6.2 genes. These findings indicate that C3R stimulated insulin secretion by promoting Ca²⁺ influx via VDCCs and activating the PLC-IP₃ pathway. C3R also upregulates the expression of genes necessary for glucose-induced insulin secretion. This is the first study describing the molecular mechanisms by which C3R stimulates Ca²⁺-dependent insulin secretion from pancreatic β-cells. These findings contribute to our understanding on how anthocyanins improve hyperglycemia in diabetic patients.

Antidiabetic Medicinal Plants Used in Democratic Republic of Congo: A Critical Review of Ethnopharmacology and Bioactivity Data

Several studies have been conducted and published on medicinal plants used to manage Diabetes Mellitus worldwide. It is of great interest to review available studies from a country or a region to resort to similarities/discrepancies and data quality. Here, we examined data related to ethnopharmacology and bioactivity of antidiabetic plants used in the Democratic Republic of Congo. Data were extracted from Google Scholar, Medline/PubMed, Scopus, ScienceDirect, the Wiley Online Library, Web of Science, and other documents focusing on ethnopharmacology, pharmacology, and phytochemistry antidiabetic plants used in the Democratic Republic of Congo from 2005 to September 2021. The Kew Botanic Royal Garden and Plants of the World Online web databases were consulted to verify the taxonomic information. CAMARADES checklist was used to assess the quality of animal studies and Jadad scores for clinical trials. In total, 213 plant species belonging to 72 botanical families were reported. Only one plant, Droogmansia munamensis, is typically native to the DRC flora; 117 species are growing in the DRC and neighboring countries; 31 species are either introduced from other regions, and 64 are not specified. Alongside the treatment of Diabetes, about 78.13% of plants have multiple therapeutic uses, depending on the study sites. Experimental studies explored the antidiabetic activity of 133 plants, mainly in mice, rats, guinea pigs, and rabbits. Several chemical classes of antidiabetic compounds isolated from 67 plant species have been documented. Rare phase II clinical trials have been conducted. Critical issues included poor quality methodological protocols, author name incorrectly written (16.16%) or absent (14.25%) or confused with a synonym (4.69%), family name revised (17.26%) or missing (1.10%), voucher number not available 336(92.05%), ecological information not reported (49.59%). Most plant species have been identified and authenticated (89.32%). Hundreds of plants are used to treat Diabetes by traditional healers in DRC. However, most plants are not exclusively native to the local flora and have multiple therapeutic uses. The analysis showed the scarcity or absence of high-quality, in-depth pharmacological studies. There is a need to conduct further studies of locally specific species to fill the gap before their introduction into the national pharmacopeia.

Prevalence, knowledge, and perception about the use of herbal medicines jazan - Saudi Arabia

Aim:

This study aimed to assess the prevalence, knowledge and perception of Jazan province residents about traditional herbal medication.

Materials and Methods:

A cross-sectional study was done on 440 Saudi residents using an electronically distributed questionnaire. The questionnaire included 39 items divided into 4 parts. Data collected were about demographic characters, knowledge and perception about HM, and HM usage among participants.

Results:

Most of the participants used HM for therapeutic purposes (80.9%) and (29.5%) believed that mixing herbs together led to more effective results. The participants agreed to a very high degree that inherited culture plays an important role in HM use, however (84.5%) of them never used herbs. The participants used herbs mostly for treatment of diabetes mellitus representing (37%) and hypertension (20.5%). Age, marital status, and the job of participants had a statistically significant effect on participants’ views about HM. While, gender, educational level, income, place of residence and chronic diseases had no statistically significant effect.

Conclusion:

The highest percentage of the participants used HM for therapeutic purposes. Increasing awareness of Saudi population about instructions and restrictions when using HM is greatly needed.

Pathology, Risk Factors, and Oxidative Damage Related to Type 2 Diabetes-Mediated Alzheimer's Disease and the Rescuing Effects of the Potent Antioxidant Anthocyanin

The pathology and neurodegeneration in type 2 diabetes- (T2D-) mediated Alzheimer's disease (AD) have been reported in several studies. Despite the lack of information regarding the basic underlying mechanisms involved in the development of T2D-mediated AD, some common features of the two conditions have been reported, such as brain atrophy, reduced cerebral glucose metabolism, and insulin resistance. T2D phenotypes such as glucose dyshomeostasis, insulin resistance, impaired insulin signaling, and systemic inflammatory cytokines have been shown to be involved in the progression of AD pathology by increasing amyloid-beta accumulation, tau hyperphosphorylation, and overall neuroinflammation. Similarly, oxidative stress, mitochondrial dysfunction, and the generation of advanced glycation end products (AGEs) and their receptor (RAGE) as a result of chronic hyperglycemia may serve as critical links between diabetes and AD. The natural dietary polyflavonoid anthocyanin enhances insulin sensitivity, attenuates insulin resistance at the level of the target tissues, inhibits free fatty acid oxidation, and abrogates the release of peripheral inflammatory cytokines in obese (prediabetic) individuals, which are responsible for insulin resistance, systemic hyperglycemia, systemic inflammation, brain metabolism dyshomeostasis, amyloid-beta accumulation, and neuroinflammatory responses. In this review, we have shown that obesity may induce T2D-mediated AD and assessed the recent therapeutic advances, especially the use of anthocyanin, against T2D-mediated AD pathology. Taken together, the findings of current studies may help elucidate a new approach for the prevention and treatment of T2D-mediated AD by using the polyflavonoid anthocyanin.

Purple corn extract (PCE) alleviates cigarette smoke (CS)-induced DNA damage in rodent blood cells by activation of AMPK/Foxo3a/MnSOD pathway

Purple corn extract (PCE) is a nutraceutical, an activator of AMPK, and it has antioxidants and anticancer properties. Therefore, PCE could be a candidate for alleviating cigarette smoke (CS)-induced oxidative DNA damage. This study examined whether PCE can have a protective effect on blood cells in an animal model of cigarette smoke (CS)-induced DNA damage. PCE was orally administered to CS-inhaled Spraque-Dawley (SD) rats, followed by the target cells being examined for markers of DNA damage. The study also sought to elucidate the mechanism of PCE action in the PCE treated animals. SD rat inhalation of CS was for once a day for 30 min, repeated for 7 days. PCE was administered orally before CS inhalation. Pretreatment of the animals with oral PCE kept the numbers of white blood cells (WBC) as well as neutrophils (NE), lymphocytes (LY), monocytes (Mo), eosinophils (EO), abd jasophils (BA) from increasing as those were increased in the CS-inhaling SD rats. The amount of phosphorylated γ-H2AX, a DNA damage marker, was assayed in the circulating blood cells collected from the animals and western blot analysis with anti-Foxo3a, p-Foxo3a, p-AMPK, MnSOD antibodies were performed on those cells. PCE protected the circulating blood cells from CS inhalation-induced DNA damage by 44% as assayed by increases in γ-H2AX. PCE also increased the nuclear localization of Foxo3a by 52% over control cells. Mechanistically, PCE appears to efficiently protect various blood cell types from CS-induced DNA damage through removal of ROS via activation of the AMPK/Foxo3a/MnSOD pathway.

Plants from the genus Eugenia as promising therapeutic agents for the management of diabetes mellitus: A review

This review combined scientific data regarding the use of genus Eugenia plants for the management of diabetes. Diabetes mellitus is a chronic metabolic disease mainly characterized by hyperglycaemia, which can lead to serious health complications. Scientists have been seeking therapeutic compounds in plants, reporting the species of the genus Eugenia as a potential source of phytochemicals with antidiabetic properties. In vitro and in vivo studies have proved that the bioactive compounds in the genus Eugenia can positively affect the biomarkers of diabetes. We discussed the phytochemical profile of the genus Eugenia and its mechanism of action on diabetes, which could modulate carbohydrate metabolism, glucose homeostasis, and insulin secretion, inhibit carbohydrases and reduce oxidative stress, suppressing the formation of advanced glycation end-products and protecting/regenerating pancreatic β-cells. Therefore, plants of the genus Eugenia showed therapeutic potential to be used in the treatment of diabetes and its comorbidities.

Anthocyanin Pigments: Beyond Aesthetics

Anthocyanins are polyphenol compounds that render various hues of pink, red, purple, and blue in flowers, vegetables, and fruits. Anthocyanins also play significant roles in plant propagation, ecophysiology, and plant defense mechanisms. Structurally, anthocyanins are anthocyanidins modified by sugars and acyl acids. Anthocyanin colors are susceptible to pH, light, temperatures, and metal ions. The stability of anthocyanins is controlled by various factors, including inter and intramolecular complexations. Chromatographic and spectrometric methods have been extensively used for the extraction, isolation, and identification of anthocyanins. Anthocyanins play a major role in the pharmaceutical; nutraceutical; and food coloring, flavoring, and preserving industries. Research in these areas has not satisfied the urge for natural and sustainable colors and supplemental products. The lability of anthocyanins under various formulated conditions is the primary reason for this delay. New gene editing technologies to modify anthocyanin structures in vivo and the structural modification of anthocyanin via semi-synthetic methods offer new opportunities in this area. This review focusses on the biogenetics of anthocyanins; their colors, structural modifications, and stability; their various applications in human health and welfare; and advances in the field.

Effects of phytochemicals on cellular signaling: reviewing their recent usage approaches

Most of the previous studies in last three decades report evidence of interactions between the different phytochemicals and the proteins involved in signal transduction pathways using in silico, in vitro, ex vivo, and in vivo analyses. However, extrapolation of these findings for clinical purposes has not been that fruitful. The efficacy of the phytochemicals in vivo studies is limited by parameters such as solubility, metabolic degradation, excretion, etc. Various approaches have now been devised to circumvent these limitations. Recently, chemical modification of the phytochemicals are demonstrated to reduce some of the limitations and improve their efficacy. Similar to traditional medicines several combinatorial phytochemical formulations have shown to be more efficient. Further, phytochemicals have been reported to be even more efficient in the form of nanoparticles. However, systematic evaluation of their efficacy, mode of action in pathway modulation, usage and associated challenges is required to be done. The present review begins with basic understanding of how signaling cascades regulate cellular response and the consequences of their dysregulation further summarizing the developments and problems associated with the dietary phytochemicals and also discuss recent approaches in strengthening these compounds in pharmacological applications. Only context relevant studies have been reviewed. Considering the limitations and scope of the article, authors do not claim inclusion of all the early and recent studies.

THE EFFECT OF ADMINISTERING MANGOSTEEN RIND EXTRACT (Garnicia mangostana l) COMPARED WITH GLIMEPIRIDE TO THE BLOOD SUGAR LEVELS OF WHITE MALE RAT (Rattus norwegicus l) INDUCED BY STREPTOZOTOCIN

The purpose of this study is to prove the differential effect of administering the mangosteen Rind extract due to lowering the blood sugar levels of Winstar white male rats induced by streptozotosin (STZ). This study used a randomized design of the ramdomized posttest only control group design. The sample consisted of 4 groups with a sample size of 7 animals each group of rats. All samples were prepared STZ induction of diabetes with a single dose of 50 mg/Kg BW through intraperitoneal (IP). K0 (control group; given 1% CMC 1 cc/day), K1 (treatment group 1; given 0,054 mg glimepiride/200 grBW, K2 (treatment group 2; given mangosteen Rind extract 50 mg/Kg BW), K3 (treatment group 3; given the mangosteen Rind extract 100 mg/Kg BW). Timing of therapy in each group was for 7 days. Shapiro-Wilk normality test (a=0.05) in the BW D variable data, pre-post STZ GDP and D GDP. Testing homogeneity used Levene's test. When data distribution was normal and homogenous, it used an ANOVA deferential test. When data distribution was normal and inhomogeneous, it proceed to apply T-test with 2 free samples. The results: 1) There were significant differences between K0 D GDP with K1 (p=0.015), K0 to K2 (p=0.003) and group K0 to K3 (p=0.002), 2) Whereas no difference was shown in the K1 with K2 (p=0.442), K1 to K3 (p=0,401) and K2 to K3 (p=0.878). Conclusion: The administration of mangosteen Rind extract doses of 50 and 100 mg/kg bw/day did not differ in lowering blood sugar levels compared with glimepiride administration of a dose of 0.054 mg/200 grBW rat/day. Mangosteen Rind extract dose of 100 mg/kg bw/day and 50 mg/kg bw/day did not provide a significant difference in lowering blood sugar levels.

Interactions between antidiabetic drugs and herbs: an overview of mechanisms of action and clinical implications

Diabetes is a complex condition with a variety of causes and pathophysiologies. The current single target approach has not provided ideal clinical outcomes for the treatment of the disease and its complications. Herbal medicine has been used for the management of various diseases such as diabetes over centuries. Many diabetic patients are known to use herbal medicines with antidiabetic properties in addition to their mainstream treatments, which may present both a benefit as well as potential risk to effective management of their disease. In this review we evaluate the clinical and experimental literature on herb-drug interactions in the treatment of diabetes. Pharmacokinetic and pharmacodynamic interactions between drugs and herbs are discussed, and some commonly used herbs which can interact with antidiabetic drugs summarised. Herb-drug interactions can be a double-edged sword presenting both risks (adverse drug events) and benefits (through enhancement). There is a general lack of data on herb-drug interactions. As such, more rigorous scientific research is urgently needed to guide clinical practice as well as to safeguard the wellbeing of diabetes patients.

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.

Alcohol-free fermented blueberry-blackberry beverage phenolic extract attenuates diet-induced obesity and blood glucose in C57BL/6J mice

The aim of this study was to determine the potential of phenolic compounds from a fermented blackberry-blueberry beverage to reduce diet-induced obesity and hyperglycemia in mice fed a 60% high-fat diet (HFD) for 10weeks after 1week of pretreatment. C57BL/6J mice were randomized into six groups and allowed to drink (ad libitum) an alcohol-free blackberry-blueberry beverage [alcohol-free fermented beverage (AFFB), 8.4mg anthocyanin (ANC)/kg body weight (BW)/day]; three doses of a phenolic extract [postamberlite extract (PAE)] from AFFB at 0.1×, 1× and 2× ANC concentrations; sitagliptin (hypoglycemic positive control); or water (negative control). Weight and fat mass gain were attenuated in mice receiving the highest doses of PAE (18.9mg ANC/kg BW/day, P<.05). There were also reductions (P<.05) in percent fat mass, epididymal fat pad weights, mean adipocyte diameters and plasma triglycerides and cholesterol associated with PAE treatments. By the end of the study, fasting blood glucose for mice receiving 9mg (1×) or 18.9mg (2×) ANC/kg BW/day was significantly lower than in the water and the sitagliptin groups (P<.05). Histological and histochemical analyses revealed an unexpected change in liver of mice fed ANC at 1× or 2× doses consisting of liver enlargement and increased lipid deposition. PAE also induced the most differential gene expression changes, including highly significant downstream effects at all doses to reduce d-glucose concentrations. Overall, phenolic compounds from the fermented blueberry-blackberry beverage had an impact to attenuate the development of obesity and fasting blood glucose in C57BL/6J mice.

Anti-diabetic effect of purple corn extract on C57BL/KsJ db/db mice

BACKGROUND/OBJECTIVES

Recently, anthocyanins have been reported to have various biological activities. Furthermore, anthocyanin-rich purple corn extract (PCE) ameliorated insulin resistance and reduced diabetes-associated mesanginal fibrosis and inflammation, suggesting that it may have benefits for the prevention of diabetes and diabetes complications. In this study, we determined the anthocyanins and non-anthocyanin component of PCE by HPLC-ESI-MS and investigated its anti-diabetic activity and mechanisms using C57BL/KsJ db/db mice.

MATERIALS/METHODS

The db/db mice were divided into four groups: diabetic control group (DC), 10 or 50 mg/kg PCE (PCE 10 or PCE 50), or 10 mg/kg pinitol (pinitol 10) and treated with drugs once per day for 8 weeks. During the experiment, body weight and blood glucose levels were measured every week. At the end of treatment, we measured several diabetic parameters.

RESULTS

Compared to the DC group, Fasting blood glucose levels were 68% lower in PCE 50 group and 51% lower in the pinitol 10 group. Furthermore, the PCE 50 group showed 2- fold increased C-peptide and adiponectin levels and 20% decreased HbA1c levels, than in the DC group. In pancreatic islets morphology, the PCE- or pinitol-treated mice showed significant prevention of pancreatic β-cell damage and higher insulin content. Microarray analyses results indicating that gene and protein expressions associated with glycolysis and fatty acid metabolism in liver and fat tissues. In addition, purple corn extract increased the phosphorylation of AMP-activated protein kinase (AMPK) and decreased phosphoenolpyruvate carboxykinase (PEPCK), glucose 6-phosphatase (G6pase) genes in liver, and also increased glucose transporter 4 (GLUT4) expressions in skeletal muscle.

CONCLUSIONS

Our results suggested that PCE exerted anti-diabetic effects through protection of pancreatic β-cells, increase of insulin secretion and AMPK activation in the liver of C57BL/KsJ db/db mice.

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.