Black Soybean Seed Coat Extract Research Articles

Anti-Inflammatory Effects of Anthocyanin-Enriched Black Soybean Seed Coat (BSSC) Crude Extract on LPS-Induced Acute Liver Injury in Mice.

Soybeans rank among the top five globally produced crops. Black soybeans contain anthocyanins in their seed coat, offering strong antioxidant and anti-inflammatory benefits. This study explores the protective effects of black soybean seed coat (BSSC) against acute liver injury (ALI) in mice. Mice pretreated with BSSC crude extract showed reduced liver damage, inflammation, and apoptosis. High doses (300 mg/kg) of the extract decreased levels of proinflammatory cytokines (IL-6, IFN-γ) and increased levels of anti-inflammatory ones (IL-4, IL-10), alongside mitigating liver pathological damage. Additionally, it influenced the Nrf2/HO-1 pathway and reduced levels of apoptosis-related proteins. In vitro, the compounds delphinidin-3-O-glucoside (D3G) and cyanidin-3-O-glucoside (C3G) in BSSC were found to modulate cytokine levels, suggesting their role in ALI protection. The study concludes that BSSC extract, particularly due to D3G and C3G, effectively protects against LPS-induced ALI in mice by inhibiting inflammation, oxidative stress, and apoptosis.

Black Soybean Seed Coat Extract Improves Endothelial Function and Upregulates Oxidative Stress Marker Expression in Healthy Volunteers by Stimulating Nitric Oxide Production in Endothelial Cells.

Black soybean seed coat extract (BE) contains multiple bioactive polyphenols, including flavan-3-ols and anthocyanins. BE improves endothelial function; however, it is unclear whether BE protects endothelial cells from senescence. In this study, we examined the effects of BE on endothelial cell senescence and vascular function in healthy individuals. High concentrations of glucose were used to induce senescence in bovine aortic endothelial cells incubated with BE. Senescence, vascular function, and oxidative stress markers were measured. Incubation with BE remarkably inhibited senescence-associated β-galactosidase and lactate dehydrogenase activities and dose dependently reduced intracellular reactive oxygen species levels in bovine aortic endothelial cells. BE treatment increased the levels of endothelial nitric oxide synthase (eNOS) mRNA and endothelial nitric oxide (NO) metabolites and increased the mRNA expression of klotho, a gene associated with an antiaging phenotype. To examine the effects of BE in humans, we conducted a clinical study using the second derivative of the fingertip photoplethysmogram to investigate vascular function and aging in 24 healthy volunteers. The participants consumed BE supplements (100 mg/day) or a placebo for 2 weeks. When compared with the placebo group, the BE group showed considerably improved vascular function, NO metabolite levels, and oxidative stress. These results suggest that BE supplementation improves endothelial function, possibly through antioxidant activity and NO production, and may consequently reduce the cardiovascular risk associated with aging. BE supplementation may be an effective and safe approach to reduce the risk of atherosclerosis and cardiovascular disease; however, additional studies investigating chronic vascular inflammation are needed.

Black soybean seed coat polyphenols have different effects on glucose and lipid metabolism in growing and young adult mice.

Black soybean contains flavan-3-ols and cyanidin 3-O-glucoside in its seed coat. Polyphenol-rich black soybean seed coat extract (BE) possesses various health benefits, such as antioxidant, anti-obesity, and anti-hyperglycemic effects. However, these functions have been evaluated mainly in the growing stage of animals, and there is no comparison data for different life stages. In this present study, we compared the effect of BE in growing (5-week old) and young adult (22-week old) ICR male mice. These mice were given an AIN 93M diet containing 2.0% BE for 4 weeks. BE did not affect body weight gain in both growing and young adult mice, but it suppressed mesenteric and subcutaneous white adipose tissue weights and decreased the cell size. BE also significantly suppressed plasma free-fatty acid levels. The effect of both BE and life stages were observed in the protein expression of adipogenesis-related transcription factors; in particular, BE suppressed the expression of C/EBPα and PPARγ. No significant change was observed in lipolysis and lipogenesis factors in the white adipose tissue and liver. Alternatively, BE showed low glucose tolerance without affecting plasma insulin levels after glucose loading in young adult mice, as seen from the results of the oral glucose tolerance test. However, plasma glucose and insulin levels remained unchanged at the end of the experimental period. In conclusion, these results strongly suggest that the health-beneficial effects of BE may alter in mice at different life stages.

Abstract 4244: Black soybean seed coat extract suppress intestinal tumorigenesis in APCmin mice

Abstract Background: Colorectal cancer (CRC) is a major cause of cancer-related deaths in Japan and worldwide. Since CRC has been reported to have close relationship with diet, it seems significant to identify dietary constituents that might suppress occurrence of CRC. Recently, an epidemiological investigation for cancer incidence in Japan revealed that consumptions of black soybeans seem to reduce incidence of several cancers, especially colorectal cancer. Black soybeans coat extract (BE) is known to contain rich procyanidins which have many beneficial physiological activities such as anticancer effects. Therefore, we hypothesized that BE may have inhibitory effects to intestinal tumorigenesis and investigated using APCmin/+ mice models. Materials and Methods: APCmin/+ male mice in the C57BL/6 genetic background were obtained from Jackson Laboratories. APCmin/+ genotypes of each mouse were confirmed by polymerase chain reaction analysis (PCR) using DNA extracted from the tip of mouse tails. Mice were weighed weekly once and monitored regularly for any signs of weight loss. APC min/+ mice at 4 weeks of age were randomly divided into three groups with 5 mice, and fed by either AIN-76A diet, AIN-76A diet containing 0.05% or 0.05% BE for 8 weeks. At 12 weeks of age, intestines were removed from each mouse and then sliced longitudinally. The small intestine was cut into three equally parts: proximal, middle, and distal. Numbers and sizes of intestinal polyps in each portion were evaluated under Video-Zoom-microscope XV-440. Intestinal polyps were categorized by size into 1-2 mm, 2-3 mm and >3 mm. Other parts of the intestines were placed in 10% phosphate-buffered formalin for histopathology and immunohistochemical (PCNA, β-catenin, and MUC2) analyses. Results: Numbers of polyps in mice fed with containing 0.05% or 0.5% BE diet were significantly smaller than in mice fed without BE (P < 0.05). As for size of polyps, the number of polyps of 1 to 3 mm in size was decreased in mice with BE, however, there were no significant difference for numbers of polyps more than 3 mm in size regarding diets with or without BE. With 0.05% BE diet, reduction rates for occurrence of polyps were 81% for proximal, 48% for middle, and 47% for distal positions, while in with 0.5% BE diet, those reduction rates were 71% for proximal, 59% for middle, and 58% for distal positions, respectively. From these results, the BE, either 0.05% or 0.05% concentration, showed inhibitory effects for tumorigeneses in the small intestine of APC min/+ mice. In histological analyses, the BE was induced higher expression of MUC2-positive cells in normal intestinal lesions and lower expression of β-catenin in tumor sites Conclusions: The BE showed inhibitory effects in occurrence and growth of intestinal polyps in APCmin/+ mice models. With further evaluation of mechanisms, the BE could be a promising nutrition for prevention of CRC in human. Citation Format: Yasuyuki Shimizu, Shunta Hirano, Yoko Yamashita, Tsuyoshi Fukumoto, Naritoshi Mukumoto, Ai Nakaoka, Namiko Hoshi, Takeaki Ishihara, Daisuke Miyawaki, Ashida Hitoshi, Ryohei Sasaki. Black soybean seed coat extract suppress intestinal tumorigenesis in APCmin mice. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4244.

Formation and characterization of hydrogenated soybean lecithin/TPGS nano-dispersions as a potential carrier for active herbal agents

The goal of this study was to examine the effects of lipid composition on physicochemical characteristics of hydrogenated soybean lecithin (HL)/d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) dispersions using dynamic light scattering, transmission electron microscopy, differential scanning calorimetry, and fluorescence polarization spectroscopy. Our results showed that HL-rich nano-dispersions exhibited larger size, narrower size distribution, higher negative zeta potential, more obvious phase transition regions, and lower membrane fluidity than did the TPGS-rich ones. The membrane packing order, intermolecular attraction interaction, and molecular cooperativity in the phase transition region of the HL dispersions could be reduced by the incorporation of a large amount of TPGS. Furthermore, chemical stability, a drug release profile, and free radical-scavenging capacity of HL/TPGS nano-dispersions encapsulating black soybean seed coat extract (BE) were analyzed. HL/TPGS nano-dispersions improved the stability and radical-scavenging capacity of phytochemicals, such as BE. Nano-dispersions with the molar ratio of HL/TPGS = 9/1 exhibited good storage stability, a slow BE release rate, good free radical-scavenging capacity, and high in vitro biocompatibility; thus, they could be a high-potential vehicle for carrying active herbal agents.

Black soybean seed coat extract protects Drosophila melanogaster against Pb toxicity by promoting iron absorption

Black soybean seed coat extract (BSSCE) is a rich source of anthocyanins. This study was aimed at investigating the effects of BSSCE on Lead (Pb) toxicity. Here using Drosophila melanogaster, we show that defects caused by Pb was significantly ameliorated by BSSCE supplementation. Further studies showed that BSSCE attenuated Pb-induced systemic iron deficiency by modulating genes involved in iron absorption in the midgut. Additionally, BSSCE eliminated the reactive oxygen species (ROS) generated by Pb in the midgut through improving the antioxidant defense system. The protection of BSSCE against Pb was suppressed when dietary iron was restricted. These results suggest that promotion of iron absorption plays a dominant role in protective effects of BSSCE against Pb. The findings indicated that black soybean might be a promising functional food for preventing Pb toxicity or other iron deficiency related diseases, providing novel insight into mechanisms of antioxidants in protecting against heavy metal induced impairment.

Daily consumption of black soybean (Glycine max L.) seed coat polyphenols attenuates dyslipidemia in apolipoprotein E-deficient mice

Daily consumption of black soybean seed coat polyphenols attenuates dyslipidemia in apolipoprotein E-deficient mice. • Black soybean seed coat extract (BE) rich in polyphenols, such as cyanidin glucoside. • Apolipoprotein E-deficient (ApoE −/− ) mice spontaneously develop dyslipidemia. • BE lowered serum and hepatic total cholesterol and triglyceride levels in ApoE −/− mice. • These were characteristic in ApoE −/− mice, but not in their corresponding wild-type. Black soybean ( Glycine max L.) seed coat extract (BE) is rich in polyphenols, including epicatechin, procyanidin, and cyanidin-3-glucoside. We evaluated the effects of daily consumption of BE in apolipoprotein E-deficient (ApoE −/− ) mice. ApoE −/− and wild-type BALB/c mice were fed a 20% fat diet with or without 1% BE for 8 weeks. Bodyweight was unaffected by BE. BE supplementation significantly lowered serum and hepatic total cholesterol and hepatic triglyceride levels. Hepatic mRNA expression of cholesterol 7α-hydroxylase ( Cyp7a1 ) and peroxisome proliferator-activated receptor α ( Pparα ) were significantly stimulated in ApoE −/− mice consuming the BE diet. These effects were characteristic in ApoE −/− mice, but not in their corresponding wild type. In conclusion, it is clear that dietary consumption of BE affected blood and hepatic levels of cholesterol and triglyceride in ApoE −/− mice, and consequently exerted preventive effects for dyslipidemia. Putative mechanisms include the upregulation of hepatic Cyp7a1 and Pparα mRNA expression.

The Seed Coat Extract of Black Soybean Decreases Nicotine-Induced Vascular Fiber Degradation by Suppressing Matrix Metalloproteinase 2 Expression.

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by weakening of vascular walls and progressive dilation of the abdominal aorta. Nicotine, the main component of tobacco, is reportedly associated with the development and rupture of AAA. It is desirable to attenuate the destructive effect of nicotine on vascular walls, using dietary food components. However, effective methods for preventing AAA progression using dietary food components remain unestablished. This study focuses on proanthocyanidins, well known for their potent antioxidant activity. We speculated that proanthocyanidins can suppress nicotine-induced weakening of vascular walls. To estimate the effect of black soybean seed coat extract (BSSCE), rich in proanthocyanidins, on nicotine-induced weakening of the aortic wall, mice were divided into four groups: the control diet and distilled water group (named C), BSSCE solution diet and distilled water group (named B), control diet and 0.5 mg/mL nicotine solution group (named CN), and BSSCE solution diet and 0.5 mg/mL nicotine solution group (named BN). Nicotine-induced degradation of elastin and collagen fibers were significantly suppressed in BN group. The positive areas for matrix metalloproteinase (MMP)-2 and oxidative stress in BN group were significantly decreased compared to those in CN group. These results suggest that proanthocyanidins-rich BSSCE can prevent the weakening of the aortic wall via inhibiting MMP-2 upregulation.

Insights into the potential benefits of black soybean (Glycine max L.) polyphenols in lifestyle diseases.

Black soybean (Glycine max L.), a cultivar containing abundant polyphenols in its seed coat such as anthocyanins and flavan-3-ols, has been reported to possess various health benefits toward lifestyle diseases. In this review article, the safety evaluation of polyphenol-rich black soybean seed coat extract (BE) and absorption of BE polyphenols are summarized. Additionally, we describe the antioxidant activity of BE polyphenols and their ability to induce antioxidant enzymes. The health benefits of BE and its polyphenols, such as anti-obesity and anti-hyperglycemic activities through the activation of AMP-activated protein kinase and translocation of glucose transporter 4, respectively, are also discussed. Furthermore, we found that black soybean polyphenols were involved in the improvement of vascular function. These emerging data require further investigation in scientific studies and human trials to evaluate the prevention of lifestyle diseases using black soybean polyphenols.

Suppressive effects of black soybean seed coat extract (Chrono-Care ® ) supplementation on N-methyl-N-nitrosourea-induced retinal degen eration in rats

Suppressive effects of black soybean seed coat extract (Chrono-Care ^®) supplementation on <i>N</i>-methyl-<i>N</i>-nitrosourea-induced retinal degen eration in rats

Preparation and characterization of shrimp shell waste protein-based films modified with oolong tea, corn silk and black soybean seed coat extracts

Shrimp shell wastes protein (SSWP, P) mixed with chitosan (C) were used as the sources of biopolymers to prepare active films, and different concentrations (1%, 3% and 5% w/w) of oolong tea extract (OTE), corn silk extract (CSE) and black soybean seed coat extract (BSSCE) were added as active constituents. The physicochemical properties of films, as observed by scanning electron microscopic (SEM), differential scanning calorimeter (DSC), fourier transform infrared (FT-IR) and X-ray diffraction (XRD), were strongly affected by the addition of OTE, CSE and BSSCE. The thermal stability was improved with increased concentration of the extracts. The films incorporated with 5% w/w BSSCE improved the barrier of film against the UV light with the transparency value of 15.97 mm−1. The OTE, CSE and BSSCE also enhanced the antioxidant activity of all films, especially incorporation of 5% w/w OTE. The study indicated that incorporating natural extracts with SSWP film was a feasible way to develop new biodegradable film for active packaging.

Anthocyanins from dietary black soybean potentiate glucose uptake in L6 rat skeletal muscle cells via up-regulating phosphorylated Akt and GLUT4

In order to illustrate the hypoglycemic mechanism of the dietary anthocyanins from black soybean, the effects of black soybean seed coat extract (BSSCE) and cyanidin-3-O-glucoside (Cy3G), the major anthocyanins of BSSCE on regulation of Akt and GLUT4 in L6 rat skeletal muscle cells were studied. BSSCE and Cy3G significantly augmented the glucose uptake in L6 myotubes in comparison to the normal control (p < 0.05). Especially, at 150 μg/mL of BSSCE and 40 μM of Cy3G treatment, the 2-NBDG uptake level were increased by 1.81-fold and 1.90-fold with that of normal control, respectively. Furthermore, the expressions of p-Akt and GLUT4 were also increased and the GLUT4 translocation was promoted by BSSCE and Cy3G, which indicated the involvement of the Akt/GLUT4 signal pathway in the hypoglycemic mechanism of BSSCE. Overall findings revealed that Cy3G-enriched BSSCE might be a promising functional food or medicine for the treatment of T2DM and its associated metabolic disorder.

Preparation and characterization of antioxidant and pH-sensitive films based on chitosan and black soybean seed coat extract

Antioxidant and pH-sensitive chitosan based films were developed by incorporating different amounts of black soybean seed coat extract (BSSCE). Spectroscopic analysis showed the main anthocyanins in BSSCE were cyanidin-3-O-galactoside (21.38%), cyanidin-3-O-glucoside (63.30%) and peonidin-3-O-glucoside (11.92%). Incorporation of BSSCE could greatly alter the barrier, optical and mechanical properties of chitosan film. Notably, chitosan-BSSCE films presented better water vapor and UV–vis light barrier properties and higher mechanical strength than chitosan film. However, chitosan-BSSCE films exhibited lower moisture content and transparency than chitosan film. Among all films tested, chitosan-BSSCE film containing 15 wt% of BSSCE on chitosan basis exhibited the best performance. Scanning electron microscopy showed BSSCE was uniformly distributed in chitosan-BSSCE films. Fourier transform infrared spectra of chitosan-BSSCE films further revealed chitosan could interact with BSSCE through non-covalent bonds. Importantly, chitosan-BSSCE films showed dose- and time-dependent 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. Moreover, color variations were observed in chitosan-BSSCE films by changing pH. Results suggested chitosan-BSSCE films could be used as promising antioxidant and visible pH-sensing food packing materials.

Interaction characterization of preheated soy protein isolate with cyanidin-3-O-glucoside and their effects on the stability of black soybean seed coat anthocyanins extracts

The interactions of soy protein isolate with cyanidin-3-O-glucoside were investigated to study the protective effect of protein on anthocyanin’s stability by UV–Vis spectrophotometry, Fourier transform infrared spectroscopy, circular dichroism and fluorescence spectroscopy. Preheat treatment and binding of cyanidin-3-O-glucoside effectively changed the secondary structure of soy protein isolate, with a decrease in α-helix, random coil structure and an increase in β-sheet and β-turn. The soy protein isolate preheated at 121 °C exhibited a strong binding affinity towards cyanidin-3-O-glucoside with strong Ks of 147.40 × 104 M−1 and also effectively increased the thermal and oxidation stabilities of black soybean seed coat extract via decreasing the degradation rate by 67% and 23%, respectively. Soy protein isolate interacted with cyanidin-3-O-glucoside mainly through hydrophobic interactions and static quenching process. Altogether, the results suggested that preheated soy protein isolate-cyanidin-3-O-glucoside interaction could effectively protect anthocyanins’ stability through strong binding affinity influenced by the systematic alterations in the secondary structure.

Effects of thermal sterilization on soy protein isolate/polyphenol complexes: Aspects of structure, in vitro digestibility and antioxidant activity

The main purpose of this work was to investigate the influence of typical thermal sterilization approaches (pasteurization, high-temperature sterilization) on the structure, in vitro digestibility, and antioxidant activity of soy protein isolate (SPI)/black soybean seed coat extract (BE) complexes at pH 7.0. The results of zeta potential and particle size demonstrated that the addition of BE was contributed to inhibit protein thermal aggregation. Heat sterilization resulted in protein unfolding revealed by UV–Vis, circular dichroism, and fluorescence spectroscopy analysis. The increase of BE led to the reduction of fluorescence intensity and surface hydrophobicity of SPI. Moreover, the formation of SPI/BE complexes inhibited protein digestion in vitro, while thermal sterilization promoted protein digestion. The SPI/BE complexes showed a strong radical scavenging ability both before and after thermal treatment.

Absorption, metabolism, distribution and faecal excretion of B-type procyanidin oligomers in mice after a single oral administration of black soybean seed coat extract.

We investigated the absorption, metabolism, distribution and faecal excretion of 3 B-type procyanidin oligomers, including procyanidin B2, procyanidin C1 and cinnamtannin A2, and their monomeric unit (-)-epicatechin after a single oral administration of black soybean seed coat extract (BE) to male ICR mice at 250 mg per kg body weight. Plasma, tissues and faeces samples were collected within 24 h for the determination of (-)-epicatechin, procyandidin B2, procyanidin C1 and cinnamtannin A2 with or without β-glucuronidase and sulfatase treatment by the high-performance liquid chromatography method. A portion of the B-type procyanidin oligomers and (-)-epicatechin in BE was absorbed from the small intestine after the oral administration of BE. In the plasma, absorbed procyanidins and (-)-epicatechin existed mainly as conjugates. In the tissues, procyanidin B2, procyandin C1 and cinnamtannin A2, in addition to (-)-epicatechin distributed widely, primarily in their free forms. Their conjugation occurred mainly in the small intestine, rather than in the liver. Monomeric unit (-)-epicatechin had the highest bioavailability, followed by procyanidin B2, procyanidin C1 and cinnamtannin A2.

An analysis method for flavan-3-ols using high performance liquid chromatography coupled with a fluorescence detector

Procyanidins belong to a family of flavan-3-ols, which consist of monomers, (+)-catechin and (−)-epicatechin, and their oligomers and polymers, and are distributed in many plant-derived foods. Procyanidins are reported to have many beneficial physiological activities, such as antihypertensive and anticancer effects. However, the bioavailability of procyanidins is not well understood owing to a lack of convenient and high-sensitive analysis methods. The aim of this study was to develop an improved method for determining procyanidin content in both food materials and biological samples. High performance liquid chromatography (HPLC) coupled with a fluorescence detector was used in this study. The limits of detection (LODs) of (+)-catechin, (−)-epicatechin, procyanidin B2, procyanidin C1, and cinnamtannin A2 were 3.0×10−3 ng, 4.0×10−3 ng, 14.0×10−3 ng, 18.5×10−3 ng, and 23.0×10−3 ng, respectively; the limits of quantification (LOQs) were 10.0×10−3 ng, 29.0×10−3 ng, 28.5×10−3 ng, 54.1×10−3 ng, and 115.0×10−3 ng, respectively. The LOD and LOQ values indicated that the sensitivity of the fluorescence detector method was around 1000 times higher than that of conventional HPLC coupled with a UV-detector. We applied the developed method to measure procyanidins in black soybean seed coat extract (BE) prepared from soybeans grown under three different fertilization conditions, namely, conventional farming, basal manure application, and intertillage. The amount of flavan-3-ols in these BEs decreased in the order intertillage > basal manure application > conventional farming. Commercially available BE was orally administered to mice at a dose of 250 mg/kg body weight, and we measured the blood flavan-3-ol content. Data from plasma analysis indicated that up to the tetramer oligomerization, procyanidins were detectable and flavan-3-ols mainly existed in conjugated forms in the plasma. In conclusion, we developed a highly sensitive and convenient analytical method for the analysis of flavan-3-ols, and applied this technique to investigate the bioavailability of flavan-3-ols in biological samples and to measure flavan-3-ol content in food material and plants.

Black soybean seed coat polyphenols prevent AAPH-induced oxidative DNA-damage in HepG2 cells.

Black soybean seed coat extract (BE), which contains abundant polyphenols such as procyanidins, cyanidin 3-glucoside, (+)-catechin, and (−)­epicatechin, has been reported on health beneficial functions such as antioxidant activity, anti-inflammatory, anti-obesity, and anti-diabetic activities. In this study, we investigated that prevention of BE and its polyphenols on 2,2'-azobis(2-methylpropionamide) dihydrochloride (AAPH)-induced oxidative DNA damage, and found that these polyphenols inhibited AAPH-induced formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a biomarker for oxidative DNA damage in HepG2 cells. Under the same conditions, these polyphenols also inhibited AAPH-induced accumulation of reactive oxygen species (ROS) in the cells. Inhibition of ROS accumulation was observed in both cytosol and nucleus. It was confirmed that these polyphenols inhibited formation of AAPH radical using oxygen radical absorbance capacity assay under the cell-free conditions. These results indicate that polyphenols in BE inhibit free radical-induced oxidative DNA damages by their potent antioxidant activity. Thus, BE is an effective food material for prevention of oxidative stress and oxidative DNA damages.

The dietary flavonoid myricetin regulates iron homeostasis by suppressing hepcidin expression

Hepcidin, a master regulator of iron homeostasis, is a promising target in treatment of iron disorders such as hemochromatosis, anemia of inflammation and iron-deficiency anemia. We previously reported that black soybean seed coat extract could inhibit hepcidin expression. Based on this finding, we performed a screen in cultured cells in order to identify the compounds in black soybeans that inhibit hepcidin expression. We found that the dietary flavonoid myricetin significantly inhibited the expression of hepcidin both in vitro and in vivo. Treating cultured cells with myricetin decreased both HAMP mRNA levels and promoter activity by reducing SMAD1/5/8 phosphorylation. This effect was observed even in the presence of bone morphogenic protein-6 (BMP6) and interleukin-6 (IL-6), two factors that stimulate hepcidin expression. Furthermore, mice that were treated with myricetin (either orally or systemically) had reduced hepatic hepcidin expression, decreased splenic iron levels and increased serum iron levels. Notably, myricetin-treated mice increased red blood cell counts and hemoglobin levels. In addition, pretreating mice with myricetin prevented LPS-induced hypoferremia. We conclude that myricetin potently inhibits hepcidin expression both in vitro and in vivo, and this effect is mediated by altering BMP/SMAD signaling. These experiments highlight the feasibility of identifying and characterizing bioactive phytochemicals to suppress hepcidin expression. These results also suggest that myricetin may represent a novel therapy for treating iron deficiency-related diseases.

Cyanidin-3-glucoside derived from black soybeans ameliorate type 2 diabetes through the induction of differentiation of preadipocytes into smaller and insulin-sensitive adipocytes

Black soybean is a health food has been reported to have antidiabetes effect. The onset of diabetes is closely associated with adipocyte differentiation, and at present, the effect of black soybean on adipocyte differentiation is unknown. Here, we investigated the antidiabetes effect of black soybean, and its anthocyanin cyanidin-3-glucoside (Cy3G), on adipocyte differentiation. Orally administered black soybean seed coat extract (BSSCE) reduced the body and white adipose tissue (WAT) weight of db/db mice accompanied by a decrease in the size of adipocytes in WAT. Furthermore, 3T3-Ll cells treated with BSSCE and Cy3G were observed to differentiate into smaller adipocytes which correlated with increased PPARγ and C/EBPα gene expressions, increased adiponectin secretion, decreased tumor necrosis factor-α secretion, activation of insulin signalling and increased glucose uptake. C2C12 myotubes cultured with conditioned medium, obtained from 3T3-L1 adipocyte cultures treated with Cy3G, also showed significantly increased expression of PGC-1α, SIRT1 and UCP-3 genes. Here we report that BSSCE, as well as its active compound Cy3G, has antidiabetes effects on db/db mice by promoting adipocyte differentiation. This notion is supported by BSSCE and Cy3G inducing the differentiation of 3T3-L1 preadipocytes into smaller, insulin-sensitive adipocytes, and it induced the activation of skeletal muscle metabolism. This is the first report on the modulation effect of Cy3G on adipocyte differentiation.