The aqueous extract of the leaves of Odontonema strictum (OSM) is used in folk medicine for its antihypertensive properties, and it contains a wide range of secondary metabolites, mostly polyphenols such as verbascoside and isoverbascoside, which could play a major role in the preparation of silver nanoparticles. In this study, we aimed to prepare AgNPs for the first time using the OSM leaf extract (OSM-AgNPs) to investigate their free radical-scavenging potency against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2). Dynamic light scattering (DLS), UV/Vis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS) were used to characterize the OSM-AgNPs. With a size around 100 nm and a ζ-potential of −41.1 mV, OSM-AgNPs showed a good stability and a better colloidal property due to electrostatic repulsion and the dispersity. The strong absorption peak at 3 keV in the EDX spectra indicated that silver was the major constituent. Additionally, the existence of silver atoms was confirmed by the Ag 3d5/2 peak around 367 eV in the XPS spectra. IC50 values of 116 μg/mL and 4.4 μg/mL were obtained for the scavenging activities of DPPH and H2O2, respectively. The synthetic OSM-AgNPs can be further exploited as potential antioxidant agents.
1 November 2020 in Bioorganic & Medicinal Chemistry Letters
Quinazolines have long been known to exert varied pharmacologic activities that make them suitable for use in treating hypertension, viral infections, tumors, and malaria. Since 2014, we have synthesized approximately 150 different 6,7-dimethoxyquinazoline-2,4-diamines and evaluated their antimalarial activity via structure-activity relationship studies. Here, we summarize the results and report the discovery of 6,7-dimethoxy-N4-(1-phenylethyl)-2-(pyrrolidin-1-yl)quinazolin-4-amine (20, SSJ-717), which exhibits high antimalarial activity as a promising antimalarial drug lead.
Biologically compatible vascular grafts are urgently required. The scaffoldless multi-layered vascular wall is considered to offer theoretical advantages, such as facilitating cells to form cell-cell and cell-matrix junctions and natural extracellular matrix networks. Simple methods are desired for fabricating physiological scaffoldless tissue-engineered vascular grafts. Here, we showed that periodic hydrostatic pressurization under hypoxia (HP/HYP) facilitated the fabrication of multi-layered tunica media entirely from human vascular smooth muscle cells. Compared with normoxic atmospheric pressure, HP/HYP increased expression of N-myc downstream-regulated 1 (NDRG1) and the collagen-cross-linking enzyme lysyl oxidase in human umbilical artery smooth muscle cells. HP/HYP increased N-cadherin-mediated cell-cell adhesion via NDRG1, cell-matrix interaction (i.e., clustering of integrin α5β1 and fibronectin), and collagen fibrils. We then fabricated vascular grafts using HP/HYP during repeated cell seeding and obtained 10-layered smooth muscle grafts with tensile rupture strength of 0.218-0.396 MPa within 5 weeks. Implanted grafts into the rat aorta were endothelialized after 1 week and patent after 5 months, at which time most implanted cells had been replaced by recipient-derived cells. These results suggest that HP/HYP enables fabrication of scaffoldless human vascular mimetics that have a spatial arrangement of cells and matrices, providing potential clinical applications for cardiovascular diseases. STATEMENT OF SIGNIFICANCE: Tissue-engineered vascular grafts (TEVGs) are theoretically more biocompatible than prosthetic materials in terms of mechanical properties and recipient cell-mediated tissue reconstruction. Although some promising results have been shown, TEVG fabrication processes are complex, and the ideal method is still desired. We focused on the environment in which the vessels develop in utero and found that mechanical loading combined with hypoxia facilitated formation of cell-cell and cell-matrix junctions and natural extracellular matrix networks in vitro, which resulted in the fabrication of multi-layered tunica media entirely from human umbilical artery smooth muscle cells. These scaffoldless TEVGs, produced using a simple process, were implantable and have potential clinical applications for cardiovascular diseases.
1 January 2020 in Journal of Nanotechnology Research
The present study reports a cost-effective and eco-friendly silver nanoparticles synthesis using Microsorum punctatum frond extract as a new solution in the development of therapeutic strategies against inflammation. Egg albumin denaturation model was used to ascertain the anti-inflammatory potential of the biosynthesized silver nanoparticles. Plasmon resonance surface peaked at 440 nm and particles interface were coated with organics. X-ray diffraction pattern showed nanocrystallite nature of 20.05 nm and 39.46 nm size for silver and silver chloride, respectively while the hydrodynamic diameter size was found to be 29.7 ± 9.7 nm. Elemental mapping reveals particles consisting of silver, chloride or carbon among main elements. Highly aggregated and polydispersed spherical silver grain of 10-45 nm size were depicted with electron microscopy. Biosynthesized nanoparticles significantly inhibited thermally induced albumin denaturation indicating their capability to control protein denaturation involved in the inflammatory process thus, plausibly account for the pharmaceutical use of the plant.
This study examined the synthesis of gold nanoparticles (AuNPs) with ethylene glycol extracts of Eutrema japonicum (Wasabi) and the evaluation of their antioxidant and anti-inflammatory activities.