A new, simple, and effective method to graft gallic acid (GA) onto chitosan (CS) in aqueous solution in the presence of carbodiimide and hydroxybenzotriazole was developed. The grafting amount of GA ...reached as much as 209.9 mg/g of copolymer, which appears as the highest one among the reported literature, and the grafting degree of GA to CS was adjustable with modulation of the mass ratio of GA to CS. The covalent insertion of GA onto the polymeric backbones was confirmed by UV–vis and 1H NMR analyses. Grafting endowed the resulting copolymer GA-grafted-CS (GA-g-CS) with both the advantages of CS and GA. The antioxidant capacity of GA-g-CS was much higher than that of the plain CS examined by assays of DPPH, superoxide, and ABTS radicals scavenging activities, reducing power, chelating power, inhibition of lipid peroxidation, ferric reducing antioxidant potential, and β-carotene-linoleic acid assays. Particularly, GA-g-CS showed significantly higher antioxidant activity than GA in β-carotene-linoleic acid assay. Furthermore, the viscosity of GA-g-CS was significantly higher than that of CS. The present study developed a novel approach to synthesize GA-g-CS that could be a potential biomaterial in food industries.
Increasing evidence has shown that dicaffeoylquinic acids (DiCQAs) have anti-inflammatory activity. However, the underlying molecular mechanisms of the anti-inflammatory effects of DiCQAs are still ...unclear. In the present study, the anti-inflammatory effects of DiCQAs from the leaves of Ilex kudingcha and the potential molecular mechanisms on LPS-induced inflammatory responses in RAW264.7 macrophage cells were investigated. The results showed that pretreatment with DiCQAs could suppress the production of NO, PGE2 and also pro-inflammatory cytokines TNF-α, IL-1β and IL-6, and the mRNA expression of two major inflammatory mediators of COX-2 and iNOS. The phosphorylated IκBα, ERK, JNK and p38 proteins in LPS-treated cells were significantly increased, which could be reversed by pretreatment with DiCQAs in a concentration-dependent manner. Taken together, the results suggest that DiCQAs from I. kudingcha have potent anti-inflammatory effects on LPS-induced inflammatory responses by inhibiting the NF-κB and MAPKs pathways and may be a prophylactic for inflammation.
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•DiCQAs could reduce NO and PGE2 by down-regulating mRNA and protein expression.•DiCQAs could decrease inflammatory cytokines by inhibiting mRNA expression.•DiCQAs suppressed inflammation through blocking NF-κB and MAPKs signaling pathways.
Muscle exercise induces intramuscular triglyceride (TG) accumulation and promotes mitochondrial maintenance in myotubes. However, the mechanism underlying exercise effects remains unknown. In this ...study, lactic acid was tested as a signaling molecule in C2C12 myotubes to understand the mechanism. Intracellular TG storage was induced in the cells by sodium lactate. The lactate activity was observed with an inhibition of the cAMP-PKA pathway as indicated by a reduction in the phosphorylation status of CREB (pCREB). Induction of pCREB signal by forskolin was blocked by pretreatment of cells with lactate. The impact of lactate on mitochondrial function was examined with a focus on the activities of two enzymes, MCAT (malonylCoA:ACP transferase) and PDH (pyruvate dehydrogenase). The enzyme activities were induced in the cells by lactate. Expression of the lactate receptor (GPR81) and lactate transporters (MCT1/4) were induced as well by lactate. The lactate activities were observed at concentrations between 4-64 mM, and were not dependent on the increase in intracellular pyruvate. Pyruvate treatment did not generate the same effects in the cells. Those results suggest that lactate may induce intramuscular TG storage and mitochondrial maintenance in myotubes through inhibition of the cAMP pathway by activation of GPR81 in a positive feedback manner.
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•The polysaccharide from Flammulina velutipes named FVP were extracted and analyzed to assess its characters.•By animal experiment, FVP can reduce the pH value and increase the ...content of SCFAs in mice intestinal lumen.•FVP can change the mice fecal microbe diversity became richness, the composition of fecal microbe was significantly altered.•FVP can increase the immunoglobulin and immune factors in mice serum.
A crude polysaccharide derived from Flammulina velutipes (FVP), mainly consisting of glucose linked with β-glycosidic bonds, was administered to 6 week-old male ICR mice by gavage for five weeks, to investigate the effects on mice intestinal microbiota and immune response. The pH of the intestinal compartments decreased while short chain fatty acids concentrations increased in FVP-fed groups, in a dose dependent manner. High throughput sequencing revealed the enrichment in the diversity and an alteration in the composition of the fecal microbiota in the FVP fed mice. A significant decrease in the Firmicutes/Bacteroidetes ratio, relative abundances of Lactobacillus and Akkermansia were related to the energy absorption. The relative abundances of Porphyromonadaceae and Bacteroidaceae positively correlated with an increase in serum immunoglobulin and cytokines. This study indicated that this crude polysaccharide from F. velutipes could modulate the gut microbiota and represented a potential capacity of obesity suppression and immune regulation.
Imaging of microRNA (miRNA) in living cells could facilitate the monitoring of the expression and distribution of miRNA and research on miRNA-related diseases. Given the low expression levels and ...even down-regulation of cellular miRNA that is associated with some diseases, enzyme-free amplification strategies are imperative for intracellular miRNA assay. In this work, we report an entropy-driven reaction for amplification assay miRNA with a detection limit of 0.27 pM. The resulting signal amplification provides excellent recognition and signal enhancement of specific miRNAs in living cells. This method supplies accurate information regarding cellular miRNA-related biological events and provides a new tool for highly sensitive and simultaneous imaging of multiple low-level biomarkers, thereby improving the accuracy of early disease diagnosis.
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•An enzyme-free amplification strategy for microRNA assay is reported.•This strategy is employed to image miRNA in single cells by using entropy-driven reaction.•The method provides a high sensitivity with a detection limit of 0.27 pM of Let-7a.
For the first time, a novel dithiomaleimides (DTM) based tetra-antennary GalNAc conjugate was developed, which enable both efficient siRNA delivery and good traceability, without incorporating extra ...fluorophores. This conjugate can be readily constructed by three click-type reactions, that is, amidations, thiol-dibromomaleimide addition and copper catalyzed azide–alkyne cycloaddition (CuAAC). And it also has comparable siRNA delivery efficiency, with a GalNAc L96 standard to mTTR target. Additionally, due to the internal DTMs, a highly fluorescent emission was observed, which benefited delivery tracking and reduced the cost and side effects of the extra addition of hydrophobic dye molecules. In all, the simple incorporation of DTMs to the GalNAc conjugate structure has potential in gene therapy and tracking applications.
Highlights • A new rat model of chronic fatigue induced by exercise is established. • Increased 5-HT in the CNS is important in chronic fatigue adjustment. • Expression changes of 5-HT receptors ...indicate elevated 5-HT at the synapse.
Intestinal microbiota plays an important role in human health. The aim of this paper is to determine the impact of the phenolics and carbohydrate in buckwheat honey on human intestinal microbiota. We ...investigated the phenolics and carbohydrate compositions of eight buckwheat honey samples using high-performance liquid chromatography and ion chromatography. The human intestinal microbes were cultured in a medium supplemented with eight buckwheat honey samples or the same concentration of fructooligosaccharides. The bacterial 16S rDNA V4 region sequence of DNA extraction was determined by the Illumina MiSeq platform. 12 phenolics and 4 oligosaccharides were identified in almost all buckwheat honey samples, namely, protocatechuic acid, 4-hydroxy benzoic acid, vanillin, gallic acid, p-coumaric acid, benzoic acid, isoferulic acid, methyl syringate, trans,trans-abscisic acid, cis,trans-abscisic acid, ferulic acid, 4-hydroxybenzaldehyde, kestose, isomaltose, isomaltotriose, and panose. Most notably, this is the first study to reveal the presence of 4-hydroxybenzaldehyde in buckwheat honey. 4-Hydroxybenzaldehyde seems to be a land marker of buckwheat honey. Our results indicate that buckwheat honey can provide health benefits to the human gut by selectively supporting the growth of indigenous Bifidobacteria and restraining the pathogenic bacterium in the gut tract. We infer that buckwheat honey may be a type of natural intestinal-health products.
•Gallic acid grafted chitosan-caseinophosphopeptide nanoparticle was developed.•The nanoparticle had antioxidant and anticancer activities.•The nanoparticle controlled release of EGCG under simulated ...gastrointestinal fluid.•The nanoparticle prevented EGCG degradation under neutral or alkaline environment.•The nanoparticle amplified anticancer activity of EGCG against colon cancer cells.
Polymer nanoparticles assembled from gallic acid (GA) grafted chitosan (CS, GA-g-CS for GA grafted CS) and caseinophosphopeptides (CPP) were developed to deliver (−)-epigallocatechin-3-gallate (EGCG) as novel functional foods. The contents of GA in GA-g-CS copolymers were in the range of 26.5 ± 1.0–126.0 ± 1.1 mg/g, with the increase of molar ratio of GA to glucosamine in CS. Compared with CS, GA-g-CS possessed much higher solubility under neutral and alkaline environments. Spherical and physicochemical stable nanoparticles assembled from GA-g-CS and CPP were obtained with particle size around 300 nm and zeta potential of less than +30 mV. The GA-g-CS-CPP nanoparticles showed strong antioxidant activity and cytotoxicity against Caco-2 colon cancer cells. The EGCG-loaded GA-g-CS-CPP nanoparticles (84–90% for encapsulation efficiency) showed improved delivery property, controlling release of EGCG under simulated gastrointestinal environments, preventing its degradation under neutral and alkaline environments, and amplifying its anticancer activity against Caco-2 cells.
Highly sensitive detection of proteins is essential to biomedical research as well as clinical diagnosis. However, usual detecting methods are complicated operating, time-costing and extensive label ...preparing. Here, we combined molecular beacon (MB) track mediated DNA walker and nicking enzyme assisted signal amplification method to develop a simple and ultrasensitive malachite green fluorescence biosensor for specific detection cytokine, interferon-γ (IFN-γ). The association of the IFN-γ with the corresponding aptamers of the dsDNA strands leads to free of DNA walker which trigged the generation of DNA track at the help of Nicking endonuclease (Nb.BbvCI). The released MB track opens MB2 to form MB track/MB2 duplex and the duplex cleaved the MB track with the help of Nb.BbvCI. The DNA track is subsequently released to hybridize with another MB2. And the cleavage also generates the G-rich oligomer, this released G-rich oligomer folds into a G-quadruplex structure and thus allows the formation of a fluorescence transducer in the presence of Malachite green (MG). The formed fluorescence transducer can give a high fluorescence intensity. So, one IFN-γ can initiate the cleavage of numerous MB track and MB2, resulting in the highly sensitive detection of IFN-γ with the detection limit of 7.65 fM. This new methodology can be expected to provide a highly sensitive platform for the amplified analysis of various target molecules.
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•A DNA walker and nicking enzyme assisted biosensor was reported here.•Strong enhancement in fluorescent signal of malachite green was utilized.•This biosensor was employed for the detection of IFN-γ with a detection limit of 7.65 fM.
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