1-Deoxynojirimycin modulates glucose homeostasis by regulating the combination of IR-GlUT4 and ADIPO-GLUT4 pathways in 3T3-L1 adipocytes.

1-Deoxynojirimycin (DNJ), the main alkaloid in mulberry leaves, was recognized to treat patients with type 2 diabetes mellitus (T2DM). However, the regulatory mechanism of DNJ on glucose homeostasis was still unclear. In the present study, a safe concentration of 0.1-10 µmol/L for DNJ was incubated with mature 3T3-L1 adipocytes. The results demonstrated that the genes/proteins expression of insulin receptor (IR), phosphatidylinositol-3-kinase (PI3K), protein kinase B (AKt/PkB), and adiponectin (ADIPO) increased with the increasing of DNJ concentration from 0.1-10 µmol/L. However the mRNA expression of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), glucose transporter 4 (GLUT4) and glucose absorption increased to the maximum at concentration of 5 µmol/L then decreased with further increase of DNJ concentration to 10 µmol/L. Both IR and ADIPO signaling pathways simultaneously affect the glucose homeostasis regulation effect of DNJ, whereas the key response target located in AMPK and its effect on subsequent GLUT4 mRNA expression.

Effect of 1-Deoxynojirimycin Isolated from Mulberry Leaves on Glucose Metabolism and Gut Microbiota in a Streptozotocin-Induced Diabetic Mouse Model.

1-Deoxynojirimycin (DNJ) exerts hypoglycemic effects. However, the traditional method for DNJ extraction is inefficient, and the hypoglycemic mechanism of DNJ remains unclear. In this study, the mixed fermentation by Lactobacillus fermentum and Saccharomyces cerevisiae was used to enhance DNJ extraction efficiency. It was found that this strategy was more efficient than the traditional method as the yield improved from the original 3.24 mg/g to 5.97 mg/g. The purified DNJ significantly decreased serum glucose (P < 0.01) and insulin levels (P < 0.05), improved serum lipid levels (P < 0.05), and reversed insulin resistance (P < 0.05) in diabetic mice. These changes were caused by up-regulating the protein expression of insulin receptor and glycolysis enzymes (GK, PK, and PFK) (P < 0.05) and down-regulating the protein expression of insulin receptor substrate-1 and gluconeogenesis enzymes (PCB, PEPCK, FBPase, and G-6-Pase) (P < 0.05), thus alleviating glucose tolerance. Additionally, DNJ treatment relieved gut dysbiosis in diabetic mice by promoting the growth of Lactobacillus, Lachnospiraceae NK4A136 group, Oscillibacter, norank Lachnospiraceae, Alistipes, and Bifidobacterium (P < 0.05) and suppressing the growth of Ruminococcaceae UCG-014, Weissella, Ruminococcus, Prevotellaceae Ga6A1 group, Anaerostipes, Klebsiella, Prevotellaceae UCG-001, and Bacteroidales S24-7 group (P < 0.05).

Mulberry leaf phenolics ameliorate hyperglycemia-induced oxidative stress and stabilize mitochondrial membrane potential in HepG2 cells.

To investigate the effect of phenolics in mulberry leaves (mulberry leaf phenolics; MLP) on hyperglycemia-induced oxidative stress and mitochondrial membrane potential (ΔΨm) in HepG2 cells; we treated HepG2 with glucose [5.5 (N-Glc) or 50 mmol/L (Hi-Glc)] with or without MLP at 10 or 100 µmol/L gallic acid equivalents and assessed level of reactive oxidant species (ROS), ΔΨm, malondialdehyde (MDA) and nuclear factor-kappaB (NF-κB) activation. Hi-Glc-induced oxidative damage was demonstrated by a series of increase in superoxides (560%, 0.5 h), MDA (400%, 24 h), NF-κB activation (474%, 4 h) and a wild fluctuation of ΔΨm relative to the control cells (p ≤ 0.05). MLP treatments ameliorate Hi-Glc-induced negative effects by a 40% reduction in ROS production, 34-44% reduction in MDA production, over 35% inhibition of NF-κB activation, as well as exert protective effect on HepG2 cells from change in ΔΨm. Our data show that MLP in vitro can protect hepatoctyes from hyperglycemia-induced oxidative damages.

Hyperoside downregulates the receptor for advanced glycation end products (RAGE) and promotes proliferation in ECV304 cells via the c-Jun N-terminal kinases (JNK) pathway following stimulation by advanced glycation end-products in vitro.

Hyperoside is a major active constituent in many medicinal plants which are traditionally used in Chinese medicines for their neuroprotective, anti-inflammatory and antioxidative effects. The molecular mechanisms underlying these effects are unknown. In this study, quiescent ECV304 cells were treated in vitro with advanced glycation end products (AGEs) in the presence or absence of hyperoside. The results demonstrated that AGEs induced c-Jun N-terminal kinases (JNK) activation and apoptosis in ECV304 cells. Hyperoside inhibited these effects and promoted ECV304 cell proliferation. Furthermore, hyperoside significantly inhibited RAGE expression in AGE-stimulated ECV304 cells, whereas knockdown of RAGE inhibited AGE-induced JNK activation. These results suggested that AGEs may promote JNK activation, leading to viability inhibition of ECV304 cells via the RAGE signaling pathway. These effects could be inhibited by hyperoside. Our findings suggest a novel role for hyperoside in the treatment and prevention of diabetes.

Phenolics and antioxidant activity of mulberry leaves depend on cultivar and harvest month in Southern China.

To elucidate the effects of cultivar and harvest month on the phenolic content and antioxidant activity of mulberry leaves, four major phenolics, including chlorogenic acid (ChA), benzoic acid (BeA), rutin (Rut) and astragalin (Ast), were quantified using an HPLC-UV method. Leaves from six mulberry cultivars, collected from April to October, were analyzed. The antioxidant activity of mulberry leaves was assessed by ferric reducing antioxidant power (FRAP), hydroxyl radical scavenging activity (HSA) and superoxide radical scavenging activity (SSA) assays. The results showed that the total values of the four phenolic compounds ranged from 2.3 dry weight (DW) to 4.2 mg/g DW, with ChA being the major compound. The mean total phenol (TP) content of the six cultivars ranged from 30.4 equivalents (GAE) mg/g DW to 44.7 GAE mg/g DW. Mulberry leaves harvested in May had the highest TP content. Moreover, the antioxidant activities of mulberry leaves harvested from April to October differed noticeably. In general, Kq 10 and May were considered to be a better cultivar and harvest month concerning phenolic content and antioxidant activity, respectively.

The structural color of red rose petals and their duplicates.

The observation of the surface of a red rose petal indicates that there are micropapillae on the surface and many nanofolders exist on each papilla. Here, much tinier nanorods with periodic pattern on the nanofolders can be seen by in situ atomic force microscopy (AFM). Angle-resolved UV-vis spectral measurement and reflectance UV-vis spectra by immersion red rose petal in solvents with different refractive indices demonstrate that such periodic nanostructures can induce structural color. The combination of structural color, driven by the nanostructures, and chemical color, driven by pigments, provide flowers bright color and special functions for human and animals' visual system. Biomimic polymer films, that fabricated by duplicating the petal's hierarchical micro/nano structures, exhibit only structural color by UV-vis spectra since there is no pigment introduced.

Mulberry leaf polyphenols attenuated postprandial glucose absorption via inhibition of disaccharidases activity and glucose transport in Caco-2 cells.

The present study attempted to evaluate the mechanism of action and bioactivity of mulberry leaf polyphenols (MLPs) in type-2 diabetes prevention via inhibition of disaccharidase and glucose transport. MLPs were purified with D101 resin and the main composition was determined as chlorogenic acid, rutin, benzoic acid and hyperoside. MLPs demonstrated a strong inhibitory effect on disaccharidases derived from both mouse and Caco-2 cells, and the order of IC50 value was: murine sucrase (7.065 mg mL-1) > murine maltase (4.037 mg mL-1) > Caco-2 cell maltase (0.732 mg mL-1) > Caco-2 cell sucrase (0.146 mg mL-1). MLPs showed the strongest inhibitory effect on sucrase derived from Caco-2 cells and played a role in lowering postprandial glucose mainly by inhibiting sucrase activity. The Caco-2 monolayer cell model was established to simulate the glucose transport process in the human small intestine. We found that within the concentration range of 0.5-2 mg mL-1, MLPs significantly inhibited glucose transport, and the inhibition rate increased with time and dose. The effect of phlorizin (SGLT1 inhibitor) in the control group showed a similar effect on glucose transport, revealing that MLPs may inhibit glucose transport mainly by inhibiting the SGLT1 transporter. RT-qPCR analysis confirmed that MLPs inhibited glucose absorption by suppressing the SGLT1-GLUT2 pathway via downregulation of the mRNA expression of phospholipase, protein kinase A and protein kinase C.

Superior hypoglycemic activity of mulberry lacking monosaccharides is accompanied by better activation of the PI3K/Akt and AMPK signaling pathways.

Mulberry has been used as a functional food to treat type 2 diabetes mellitus (T2DM). However, it contains relatively high levels of fructose and glucose, which are not suitable for excess consumption by diabetic patients. In this study we used microbial fermentation to remove fructose and glucose from mulberry fruit, and then determined the effects on glycemia, the phosphatidylinositol 3-hydroxykinase/Akt (PI3K/Akt) and adenosine monophosphate-activated protein kinase (AMPK) signaling pathways and their downstream effectors in T2DM mice. After 5 weeks of administration, fermented mulberry (FM) significantly reduced fasting blood glucose, and also improved insulin sensitivity and glucose tolerance, more effectively than unfermented mulberry (MP). Moreover, compared with MP, FM had a more marked effect on the protein expression of intermediates in the PI3K/Akt and AMPK signaling pathways and their effectors: insulin receptor, phosphorylated Akt (Ser 308), phosphorylated glycogen synthase kinase-3ß (Ser 9), glycogen synthetase, phosphorylated forkhead transcription factor 1 (Ser 256), pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1, 6-bisphosphatase, glucose-6-phosphatase, lipoprotein lipase, and phosphorylated AMPK (Thr 172), glucose transporter 4 and pyruvate kinase. These findings indicate that mulberry fruit modified to remove fructose and glucose may be more promising than whole mulberry as a treatment for diabetes.

Destruction of the cell membrane and inhibition of cell phosphatidic acid biosynthesis in Staphylococcus aureus: an explanation for the antibacterial mechanism of morusin.

Morusin is a prenylated flavonoid found in mulberry that shows antimicrobial activity against foodborne pathogens. The MIC values of morusin toward S. aureus ATCC 6538 and S. aureus ATCC 25923 were both 14.9 µmol L-1. This study further investigated the antimicrobial mechanism of morusin in inhibiting the growth of Staphylococcus aureus ATCC 6538. Scanning electron microscopy and transmission electron microscopy revealed that morusin disrupted the integrity of the bacterial cell membrane. Morusin may also affect the phospholipid-repair system of bacteria, which repairs membrane structures. To test this hypothesis, quantitative real-time PCR was used to examine the effect of morusin treatment of S. aureus on the regulation of genes associated with the cell phosphatidic acid biosynthesis pathway. Gas chromatography-mass spectrometry was used to investigate the fatty acid components, which are used to synthesize bacterial phosphatidic acids. In summary, the results revealed that morusin showed a potent antibacterial effect by disrupting the cell membrane architecture and inhibiting the phosphatidic acid biosynthesis pathway of S. aureus.

Highly reproducible SERS arrays directly written by inkjet printing.

SERS arrays with uniform gold nanoparticle distribution were fabricated by direct-writing with an inkjet printing method. Quantitative analysis based on Raman detection was achieved with a small standard statistical deviation of less than 4% for the reproducibility and less than 5% for the long-term stability for 12 weeks.

Mulberry leaf polyphenols delay aging and regulate fat metabolism via the germline signaling pathway in Caenorhabditis elegans.

Mulberry leaves are an important ingredient in some traditional Chinese medicinal formulas and has been developed for use in functional food products. The antioxidant activity of mulberry leaf extract has been reported to have beneficial effects on diseases in vitro; however, it is not clear which components in mulberry leaf extracts have these functions. Furthermore, the mechanisms of action of these ingredients have not been extensively investigated. In this study, we extracted total mulberry leaf polyphenols (MLP) and identified its 13 phenolic monomers. Our results, using Caenorhabditis elegans as a model, indicated that MLPs delayed aging, improved oxidative stress resistance, and reduced fatty acid storage in vivo. Subsequent genetic screens and gene expression analyses demonstrated that the functions of MLP mainly depended on the germline signaling pathway, thus influencing the activities of downstream transcription factors (DAF-12, DAF-16, PHA-4, and NHR-80) as well as the expression levels of their target genes (fat-6, lipl-4, sod-3, unc-51, and fard-1). Our study determined that diverse modes of action on longevity were promoted by MLP exposure. These observations provide the first insight into MLP's multifaceted functions on aging, fat accumulation, and reproduction in vivo and indicate a specific model for the mechanism of action of MLP. This is a significant finding that lends support to the hypotheses that mulberry leaf extracts can have an impact on human health.

Efficient luminescence of long persistent phosphor combined with photonic crystal.

In this paper, the luminescence properties of the long persistent phosphor (LPP) were apparently improved by combining with photonic crystal (PC). An optimized PC can double the afterglow intensity and prolong 1.7 times of the afterglow time of SrAl2O4: Eu, a commercially available LPP, without any dopants. These results were ascribed to the stopband effect of the PC. The PC combined LPP structure was beneficial for the applications of LPP in emergency indication which called for brighter afterglow intensity and longer afterglow time.

Direct-writing colloidal photonic crystal microfluidic chips by inkjet printing for label-free protein detection.

Integrating photonic crystals (PC) into microfluidic systems has attracted immense interest for its novel functions. However, it is still a great challenge to fabricate PC microfluidic chips rapidly with complex functions. In this work, a direct-writing colloidal PC microchannel was firstly achieved by inkjet printing and was used for the surface-tension-confined microfluidic immune assay. PC channels with different structure colors have been successfully integrated on one chip. The fabricated chip has the advantages of rapid fabrication, quick fluidic transport and can monitor the fluidic fluxion using the naked eye. Utilizing this PC microfluidic chip, a colorimetric label-free immune assay was realized without nonspecific adsorption interference of the target.

Highly effective protein detection for avidin-biotin system based on colloidal photonic crystals enhanced fluoroimmunoassay.

There has been immense interest in both instruments and methods to enhance fluorescence signal and achieve highly sensitive fluoroimmunoassay (FIA). In this paper, we present a facile, low-cost and general method of biotinylated colloidal photonic crystal (PC) to improve the FIA of avidin (avidin FIA). The fluorescence signal intensity of the avidin FIA on the colloidal PC can be enhanced over two orders of magnitude relative to the control sample, attributed to the large surface area, resonance field and coherent scattering effect of the colloidal PC. The detection limit is shrunk to 1/69 of that of the control sample. Furthermore, the signal to interference ratio (S/I ratio) is increased because the band-edge induced fluorescence enhancement is wavelength-selective. The interference fluorescence does not go up proportionally while the signal is significantly enhanced by the colloidal PCs. It is believed that the colloidal PC modified with biotin can act as an effective material for a general and sensitive fluoroimmunoassay.