Separation and purification of amygdalin from thinned bayberry kernels by macroporous adsorption resins

To utilize the low-value thinned bayberry (Myrica rubra Sieb. et Zucc) kernels (TBKs) waste, an efficient method using macroporous adsorption resins (MARs) for separation and purification of amygdalin from TBKs crude extracts was developed. An aqueous crude sample was prepared from a methanol TBK extract, followed by resin separation. A series of MARs were initially screened for adsorption/desorption of amygdalin in the extract, and D101 was selected for characterization and method development. The static adsorption data of amygdalin on D101 was best fitted to the pseudo-second-order kinetics model. The solute affinity toward D101 at 30 °C was described and the equilibrium experimental data were well-fitted to Langmuir and Freundlich isotherms. Through one cycle of dynamic adsorption/desorption, the purity of amygdalin in the extract, determined by HPLC, increased about 17-fold from 4.8% to 82.0%, with 77.9% recovery. The results suggested that D101 resin effectively separate amygdalin from TBKs

The Progressive Utilization of Ponkan Peel Residue for Regulating Human Gut Microbiota through Sequential Extraction and Modification of Its Dietary Fibers

As a by-product of citrus processing, ponkan (Citrus reticulata Blanco, cv. Ponkan) peel residue is a source of high quality dietary fiber (DF). To make a full utilization of this resource and give a better understanding on the probiotic function of its DF, soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) were extracted from ponkan peel residue (after flavonoids were extracted) using an alkaline method, followed by modifications using a composite physical-enzymatic treatment. The in vitro fermentation properties of the modified SDF and IDF (namely, MSDF and MIDF) and their effects on short-chain fatty acids (SCFA) production and changes in the composition of human gut microbiota were investigated. Results showed that MSDF and MIDF both significantly lowered the pH value and enhanced total SCFA content in the broths after fermented for 24 h by fecal inocula (p g-Collinsella, p-Actinobacteria and g-Dialister, while those by MIDF were f-Veillonellaceae, c-Negativicutes and f-Prevotellacese. These results suggested that the modified ponkan peel residue DF can be utilized by specific bacteria in the human gut as a good source of fermentable fiber, providing a basis for the exploitation of the citrus by-product

Chemical features and machine learning assisted predictions of protein-ligand short hydrogen bonds

Abstract There are continuous efforts to elucidate the structure and biological functions of short hydrogen bonds (SHBs), whose donor and acceptor heteroatoms reside more than 0.3 Å closer than the sum of their van der Waals radii. In this work, we evaluate 1070 atomic-resolution protein structures and characterize the common chemical features of SHBs formed between the side chains of amino acids and small molecule ligands. We then develop a machine learning assisted prediction of protein-ligand SHBs (MAPSHB-Ligand) model and reveal that the types of amino acids and ligand functional groups as well as the sequence of neighboring residues are essential factors that determine the class of protein-ligand hydrogen bonds. The MAPSHB-Ligand model and its implementation on our web server enable the effective identification of protein-ligand SHBs in proteins, which will facilitate the design of biomolecules and ligands that exploit these close contacts for enhanced functions

Quantum mechanical effects in acid-base chemistry

Acid-base chemistry has immense importance for explaining and predicting the chemical products formed by an acid and a base when mixed together. However, the traditional chemistry theories used to describe acid-base reactions do not take into account the effect arising from the quantum mechanical nature of the acidic hydrogen shuttling potential and its dependence on the acid base distance. Here, infrared and NMR spectroscopies, in combination with first principles simulations, are performed to demonstrate that quantum mechanical effects, including electronic and nuclear quantum effects, play an essential role in defining the acid-base chemistry when 1-methylimidazole and acetic acid are mixed together. In particular, it is observed that the acid and the base interact to form a complex containing a strong hydrogen bond, in which the acidic hydrogen atom is neither close to the acid nor to the base, but delocalized between them. In addition, the delocalization of the acidic hydrogen atom in the complex leads to characteristic IR and NMR signatures. The presence of a hydrogen delocalized state in this simple system challenges the conventional knowledge of acid-base chemistry and opens up new avenues for designing materials in which specific properties produced by the hydrogen delocalized state can be harvested

Recyclable Multifunctional Magnetic Fe₃O₄@SiO₂@Au Core/Shell Nanoparticles for SERS Detection of Hg (II)

Mercury ions can be enriched along the food chain and even low concentrations of mercury ions can seriously affect human health and the environment. Therefore, rapid, sensitive, and highly selective detection of mercury ions is of great significance. In this work, we synthesized Fe3O4@SiO2@Au three-layer core/shell nanoparticles, and then modified 4-MPy (4-mercaptopyridine) to form a SERS sensor. Mercury ions in water can be easily captured by 4-MPy which were used as the reporter molecules, and the concentration of mercury ions can be evaluated based on the spectral changes (intensification and reduction of peaks) from 4-MPy. After the mercury ion was combined with the pyridine ring, the peak intensity at 1093 cm−1 increased with the concentration of mercury ion in the range of 10 ppm–1 ppb, while the Raman intensity ratio I (416 cm−1)/I (436 cm−1) decreased with the increase of mercury ion concentration. This magnetically separatable and recyclable SERS sensor demonstrates good stability, accuracy, and anti-interference ability and shows the potential to detect actual samples. Furthermore, we demonstrate that the probe is applicable for Hg2+ imaging in macrophage cells

Hypoglycemic effect of the Phellinus baumii extract with α-glucosidase-inhibited activity and its modulation to gut microbiota in diabetic patients

Phellinus baumii extract (PBE) possesses considerable α-glucosidase-inhibited activity. This study investigated the hypoglycemic effect in vitro and in vivo using a glucose consumption assay in HepG2 cells, intragastric administration for ten weeks in STZ-induced mice, and intestinal flora fermentation in patients with type 2 diabetes to reveal the possible underlying mechanisms. PBE was prepared, including α-glucosidase-inhibited ethanol extract (EE) and aqueous extract (AE). In vitro, PBE promoted glucose consumption and enhanced glycogen content and hexokinase activity but lowered phosphoenolpyruvate carboxylase kinase activity in HepG2 cells. In vivo, PBE treatment significantly reduced the body weight (p < 0.05) and fasting blood glucose levels of diabetic mice (p < 0.01), with the lowest blood glucose level observed in the EE+AE group. Furthermore, the serum insulin levels and insulin resistance index (HOMA) of PBE-treated groups decreased significantly (p < 0.01). Moreover, gene expression levels of the IRS-1/PI3K/AKT pathway were significantly upregulated by PBE treatment (p < 0.01). In vitro fermentation demonstrated that EE significantly inhibited the production of H2S and NH3 in the intestinal flora fermentation model in diabetic patients (p < 0.05). In addition, the ratio of Firmicutes to Bacteroidetes was reduced, the growth of Lactobacillus and Prevotella 9 was promoted, and Pseudomonas aeruginosa was inhibited. This study provides new insights and clues for using PBE as a functional food and clinical drug for glycemic control

Dendrobium officinale leaf polysaccharide has a dual effect of alleviating the syndromes of immunosuppressed mice and modulating immune system of normal mice

This study aimed to explore the immunomodulatory activity of Dendrobium officinale leaf polysaccharide (DOLP) in both immunosuppressed and normal mice. The data showed that DOLP significantly reversed thymic and splenic damage in immunosuppressed mice, regulated their peripheral blood cells (PLT, etc.), immune-related cytokines (TNF-α, INF-γ and IL-6) and immunoglobulins (IgA, IgG and IgM) production, and increased the relative abundance of beneficial bacteria (Lactobacillus and Bifidobacterium, etc.) while decreased that of pathogenic bacteria (Desulfovibrio, etc.). In normal mice, DOLP significantly increased immune-related cytokines (TNF-α, INF-γ, and IL-6), gut microbiota diversity, and the relative abundance of beneficial bacteria (unclassified_f_Lachnospiraceae_NK4A136_group, etc.). The results indicated that DOLP could exert immune modulating effects both on immunosuppressed mice and normal mice by modulating immune parameters and gut microbiota. These findings provide new insights into the immune-modulating effects of DOLP and a solid basis for the thorough utilization of DOLP

Comparison of Physicochemical Characteristics and Anticoagulant Activities of Polysaccharides from Three Sea Cucumbers

In order to search for sulfated polysaccharides in different invertebrate connective tissues and to examine their biological activities, we have isolated three types of polysaccharides from the body wall of the three sea cucumbers Holothuria edulis, Apostichopus japonicas and Holothuria nobilis. The physicochemical properties and anticoagulant activities of these polysaccharides were examined and compared. The chemical composition analysis and nuclear magnetic resonance (NMR) analysis indicate that two types of polysaccharides, sulfated fucan and fucosylated chondroitin sulfate (FuCS), were found in all of the three species and in addition a neutral glycan was observed in H. edulis. The neutral α-glucan was firstly obtained from sea cucumber. The same type of polysaccharides from different species of sea cucumbers have similar physicochemical properties and anticoagulant activities, but those of different types of glycans are significantly different, possibly due to their different monosaccharide compositions, electric charges and average molecular weights. The FuCSs have stronger anticoagulant activities than the sulfated fucans, although the molecular sizes of the FuCSs are lower than those of the sulfated fucans, whereas the neutral glucan has no activity, as expected from the absence of sulfate. Thus, anticoagulant activities of the different type of polysaccharides are likely to relate to monosaccharide composition and sulfate content. Preliminary analysis suggests that the sulfation patterns of the FuCSs may result in the difference in anticoagulant activities. Our data could help elucidate the structure-activity relationship of the sea cucumber polysaccharides