Synthesis and clinical application of representative small-molecule dipeptidyl Peptidase-4 (DPP-4) inhibitors for the treatment of type 2 diabetes mellitus (T2DM).

Diabetes mellitus is a chronic metabolic disorder characterized by high blood glucose levels, which can cause many diseases, including osteoporosis, fractures, arthritis, and foot complications. The inhibitors of dipeptidyl peptidase-4 (DPP-4), an enzyme involved in glucose metabolism regulation, are essential for managing Type 2 Diabetes Mellitus (T2DM). The inhibition of DPP-4 has become a promising treatment approach for T2DM because it can increase levels of active glucagon-like peptide-1 (GLP-1), leading to improved insulin secretion in response to glucose and reduced release of glucagon. The review commences by elucidating the role of DPP-4 in glucose homeostasis and its significance in T2DM pathophysiology. Furthermore, it presents the mechanism of action, preclinical pharmacodynamics, clinical efficacy, and toxicity profiles of small-molecule DPP-4 inhibitors across various clinical stages. This comprehensive review provides valuable insights into the synthesis and clinical application of DPP-4 inhibitors, serving as an invaluable resource for researchers, clinicians, and pharmaceutical professionals interested in diabetes therapeutics and drug development.

Isolation and characterization of cellulose nanocrystals from Chinese medicine residues.

Nanocellulose has become a vital material with excellent and crucial properties in the field of nanotechnology and advanced materials science. Plant-based traditional Chinese medicines are mostly plant rhizomes, which contain a large amount of cellulose, hemicellulose, and lignin. In this study, carboxylated cellulose nanocrystals (CNCs) were prepared from traditional Chinese medicine residues (CMR) by sequential periodate-chlorite oxidation without mechanical treatment. The obtained nanocelluloses were analyzed by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and X-ray diffractometry (XRD); the carboxyl content and specific surface area were also measured, simultaneously. XRD results revealed that the crystallinity index decreased after sequential oxidation; however, the cellulose I structure was maintained. From the morphology analysis, the average length and width of CNCs were 139.3 and 10 nm, respectively. From the FTIR analysis, with the particle size decreasing, hydrogen bonds were broken and recombined. TGA results showed that the thermal property was decreased with a reduction of nanocellulose particle size and crystallinity index. This study is the first to refine utilization of traditional Chinese medicine residues as a potential source of cellulose, that is, to prepare nanocellulose efficiently with high carboxyl content which finds its application in nanomaterials.

Preparation and characterization of cellulose nanocrystals from spent edible fungus substrate.

BACKGROUND: Spent edible fungus substrates were identified as potential sources to produce cellulose derivatives, namely purified cellulose and dicarboxyl cellulose nanocrystal (DCNC). Purified celluloses were obtained via chemical treatments and then oxidized by sequential periodate-chlorite without mechanical process. The structural properties of the DCNCs were characterized by transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). RESULTS: XRD results showed that the cellulose I structure was maintained, however, the crystallinity index decreased after oxidation process. The initial pyrolysis temperature of DCNCs ranged from 242 to 344 °C. TEM results revealed that DCNC was rod-shaped with an average length and width of 130.88 nm and 7.3 nm, respectively. The average specific surface area (SSA) was 366.67 m2  g-1 . The carboxyl content was around 3.485 mmol g-1 . Finally, the adsorption capacity for contaminations was 76.98, 126.22, 64.44 and 9.63 mg g-1 for copper ion (Cu2+ ), lead ion (Pb2+ ), chromium (Cr3+ ) and amoxicillin (AMX), respectively. CONCLUSION: This work showed a sequentially chemical oxidation for preparing nanocellulose from secondary agricultural waste with many functional applications. © 2021 Society of Chemical Industry.

Production of magnetic sodium alginate polyelectrolyte nanospheres for lead ions removal from wastewater.

Polyelectrolyte composite nanospheres are relatively new adsorbents which have attracted much attention for their efficient pollutant removal and reuse performance. A novel polyelectrolyte nanosphere with magnetic function (SA@AM) was synthesized via the electrostatic reaction between the polyanionic sodium alginate (SA) and the surface of a prepared terminal amino-based magnetic nanoparticles (AMs). SA@AM showed a size of 15-22 nm with 6.85 emu·g-1 of magnetization value, exhibiting a high adsorption capacity on Pb(II) ions representing a common heavy metal pollutant, with a maximum adsorption capacity of 105.8 mg g-1. The Langmuir isotherm adsorption fits the adsorption curve, indicating uniform adsorption of Pb(II) on the SA@AM surfaces. Repeated adsorption desorption experiments showed that the removal ratio of Pb(II) by SA@AM was more than 76%, illustrating improved regeneration performance. These results provide useful information for the production of bio-based green magnetic nano scale adsorption materials for environmental remediation applications.

[Behavioral imaging of serum albumin during matrine transport based on capillary electrophoresis].

Matrine (MT) is an alkaloid widely used in the treatment of tumor diseases. It is the main medicinal ingredient in the dried roots of kuh-seng (Sophora flavescens Ait). However, there have been few studies on its transport mechanism. Serum albumin (SA) is the most abundant protein in blood. SA combines easily with many substances, including MT. MT and human serum albumin (HSA) were analyzed by capillary electrophoresis (CE) under in vitro conditions. The capillary tubing was 50 µm. The total length of the capillary was 60 cm, the total effective length was 50 cm. The interaction models of ligand-receptor binding were constructed by the mobility and frontal analysis (FA) methods. The purpose of establishing the interaction model was to study the binding of MT and SA. The phosphate buffer solution (PBS, 0.02 mol/L) was prepared in double distilled water. All solutions were prepared in PBS (0.02 mol/L). All solutions were filtered twice through a 0.45 µm microporous membrane, degassed for 5 min at a time. In the mobility method, different gradient MT solutions were used as running buffers. Their concentrations were 1.0×10-4-1.0×10-3 mol/L, with the gradient of 1.0×10-4 mol/L. And the HSA solution containing (0.5% (v/v)) acetone was used as test sample. Its concentration was 1.0×10-5 mol/L. The nonlinear fitting method was used to obtain the binding parameters of MT and HSA. In the FA method, different gradient MT-HSA solutions were used as test samples. Their concentrations were 1.0×10-4-1.0×10-3 mol/L, with the gradient of 1.0×10-4 mol/L. And the PBS solution (0.02 mol/L) was used as running buffer. Then three equations were used to obtain the binding parameters of MT and HSA. And the applicability of the models was analyzed using the binding parameters. These three equations were nonlinear regression equation, Scatchard linear equation, and Klotz linear equation. Using the mobility method, the apparent binding constant KB was 8.072×103 mol/L. According to the FA method, three apparent binding constants were obtained for MT and HSA. The apparent binding constant KB of HSA and MT by nonlinear regression equation, Scatchard linear equation and Klotz linear equation were 1.434×103, 1.781×103 and 2.133×103 mol/L. The comparison was as follows, KB(nonlinear regression equation) < KB(Scatchard linear equation) < KB(Klotz linear equation). The number of binding sites was about 1.0. It was indicating that MT had only a single type of binding site with HSA. By analyzing the applicability of the model, the correlation coefficients (r) of the three equations were obtained. The comparison was as follows, r(Klotz linear equations) > r(nonlinear regression equations) > r(Scatchard linear equations). The results showed that both the methods were all suitable for analyzing the MT-SA system. The FA method could calculate the apparent binding constants and the numbers of binding sites. Therefore, it was more suitable for the analysis of MT and HSA. And the Klotz linear equation was the best fit for the theoretical model among the three equations. The combined parameters indicated that the interaction of MT with HSA had only one binding site. And the binding of MT with HSA was stable. This experimental method could be used to determine the binding status of MT and HSA. It is useful to further explore the binding mechanism of MT and HSA. This work provides valuable information on the interaction mechanism of typical alkaloids with SA. It will be useful in studies of the blood transport mechanisms of alkaloids.

Fabrication of Wood-Rubber Composites Using Rubber Compound as a Bonding Agent Instead of Adhesives.

Differing from the hot-pressing method in the manufacturing of traditional wood-rubber composites (WRCs), this study was aimed at fabricating WRCs using rubber processing to improve water resistance and mechanical properties. Three steps were used to make WRCs, namely, fiber-rubber mixing, tabletting, and the vulcanization molding process. Ninety-six WRC panels were made with wood fiber contents of 0%-50% at rotor rotational speeds of 15-45 rpm and filled coefficients of 0.55-0.75. Four regression equations, i.e., the tensile strength (Ts), elongation at break (Eb), hardness (Ha) and rebound resilience (Rr) as functions of fiber contents, rotational speed and filled coefficient, were derived and a nonlinear programming model were developed to obtain the optimum composite properties. Although the Ts, Eb and Rr of the panels were reduced, Ha was considerably increased by 17%-58% because of the wood fiber addition. Scanning electron microscope images indicated that fibers were well embedded in rubber matrix. The 24 h water absorption was only 1%-3%, which was much lower than commercial wood-based composites.