scholarly journals A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products

10.3791/53593 ◽  
2016 ◽  
Author(s):  
Christopher E. Malmberg ◽  
Stephen Chamberland
Keyword(s):  
Natural Products ◽  
Early Stage

scholarly journals Simultaneous Assessment of the Efficacy and Toxicity of Marine Mollusc–Derived Brominated Indoles in an In Vivo Model for Early Stage Colon Cancer

2017 ◽  
Vol 17 (2) ◽  
pp. 248-262 ◽  
Author(s):  
Babak Esmaeelian ◽  
Kirsten Benkendorff ◽  
Richard K. Le Leu ◽  
Catherine A. Abbott
Keyword(s):  
Colon Cancer ◽  
Natural Products ◽  
Liver Toxicity ◽  
Early Stage ◽  
Blood Biochemistry ◽  
In Vivo Model ◽  
Liver Histopathology ◽  
Genotoxic Carcinogens ◽  
Early Stage Colon Cancer

The acute apoptotic response to genotoxic carcinogens animal model has been extensively used to assess the ability of drugs and natural products like dietary components to promote apoptosis in the colon and protect against colorectal cancer (CRC). This work aimed to use this model to identify the main chemopreventative agent in extracts from an Australian mollusc Dicathais orbita, while simultaneously providing information on their potential in vivo toxicity. After 2 weeks of daily oral gavage with bioactive extracts and purified brominated indoles, mice were injected with the chemical carcinogen azoxymethane (AOM; 10 mg/kg) and then killed 6 hours later. Efficacy was evaluated using immunohistochemical and hematoxylin staining, and toxicity was assessed via hematology, blood biochemistry, and liver histopathology. Comparison of saline- and AOM-injected controls revealed that potential toxic side effects can be interpreted from blood biochemistry and hematology using this short-term model, although AOM negatively affected the ability to detect histopathological effects in the liver. Purified 6-bromoisatin was identified as the main cancer preventive agent in the Muricidae extract, significantly enhancing apoptosis and reducing cell proliferation in the colonic crypts at 0.05 mg/g. There was no evidence of liver toxicity associated with 6-bromoisatin, whereas 0.1 mg/g of the brominated indole tyrindoleninone led to elevated aspartate aminotransferase levels and a reduction in red blood cells. As tyrindoleninone is converted to 6-bromoisatin by oxidation, this information will assist in the optimization and quality control of a chemopreventative nutraceutical from Muricidae. In conclusion, preliminary data on in vivo safety can be simultaneously collected when testing the efficacy of new natural products, such as 6-bromoisatin from Muricidae molluscs for early stage prevention of colon cancer.

scholarly journals Neoglycosylation and neoglycorandomization: enabling tools for the discovery of novel glycosylated bioactive probes and early stage leads

MedChemComm ◽  
2014 ◽  
Vol 5 (8) ◽  
pp. 1036-1047 ◽  
Author(s):  
Randal D. Goff ◽  
Jon. S. Thorson
Keyword(s):  
Natural Products ◽  
Small Molecules ◽  
Early Stage

Alkoxyamine-based strategies for the rapid chemoselective conjugation of sugars to drugs, natural products and bioactive small molecules.

Divergent Total Syntheses of Enmein-Type Natural Products: (–)-Enmein, (–)-Isodocarpin and (–)-Sculponin R

2018 ◽  
Author(s):  
Guangbin Dong ◽  
Saiyong Pan ◽  
Sicong Chen
Keyword(s):  
Natural Products ◽  
Early Stage ◽  
One Pot ◽  
Total Syntheses ◽  
Key Features

Divergent total syntheses of enmein-type natural products, (–)-enmein, (–)-isodocarpin and (–)-sculponin R, have been achieved in a concise fashion. Key features of the strategy include (a) an efficient early-stage cage formation to control succeeding diastereoselectivity, (b) an one-pot acylation/akylation/lactonization to construct the C-ring and C8 quarternary center, (c) a reductive alkenylation approach to construct enmain D/E rings and (d) a flexible route to allow divergent syntheses of three natural products.

Divergent Total Syntheses of Enmein-Type Natural Products: (–)-Enmein, (–)-Isodocarpin and (–)-Sculponin R

2018 ◽  
Author(s):  
Guangbin Dong ◽  
Saiyong Pan ◽  
Sicong Chen
Keyword(s):  
Natural Products ◽  
Early Stage ◽  
One Pot ◽  
Total Syntheses ◽  
Key Features

Divergent total syntheses of enmein-type natural products, (–)-enmein, (–)-isodocarpin and (–)-sculponin R, have been achieved in a concise fashion. Key features of the strategy include (a) an efficient early-stage cage formation to control succeeding diastereoselectivity, (b) an one-pot acylation/akylation/lactonization to construct the C-ring and C8 quarternary center, (c) a reductive alkenylation approach to construct enmain D/E rings and (d) a flexible route to allow divergent syntheses of three natural products.

scholarly journals Natural Products and Obesity: A Focus on the Regulation of Mitotic Clonal Expansion during Adipogenesis

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1157 ◽  
Author(s):  
Eugene Chang ◽  
Choon Kim
Keyword(s):  
Cell Cycle ◽  
Natural Products ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Early Stage ◽  
Inhibitory Effects ◽  
Health Crisis ◽  
Health Complications ◽  
Key Steps

Obesity is recognized as a worldwide health crisis. Obesity and its associated health complications such as diabetes, dyslipidemia, hypertension, and cardiovascular diseases impose a big social and economic burden. In an effort to identify safe, efficient, and long-term effective methods to treat obesity, various natural products with potential for inhibiting adipogenesis were revealed. This review aimed to discuss the molecular mechanisms underlying adipogenesis and the inhibitory effects of various phytochemicals, including those from natural sources, on the early stage of adipogenesis. We discuss key steps (proliferation and cell cycle) and their regulators (cell-cycle regulator, transcription factors, and intracellular signaling pathways) at the early stage of adipocyte differentiation as the mechanisms responsible for obesity.

scholarly journals Screening of Microbial Natural Products and Biological Evaluation of Trichomicin as Potential Anti-Cytokine Storm Agents

2021 ◽  
Vol 12 ◽  
Author(s):  
Yu Chen ◽  
Zhuochen Zhuang ◽  
Jing Yang ◽  
Liping Bai
Keyword(s):  
Natural Products ◽  
Early Stage ◽  
Biological Evaluation ◽  
The Body ◽  
Cytokine Storm ◽  
Storm Activity ◽  
Tnf Α ◽  
Microbial Natural Products

COVID-19 has remained an uncontained, worldwide pandemic. Most of the infected people had mild symptoms in the early stage, and suddenly worsened or even died in the later stage which made the cytokine release syndrome (CRS) once again aroused people’s attention. CRS is an excessive immunity of the body to external stimuli such as viruses, bacteria, and nanomaterials, which can cause tissue damage, local necrosis or even death. Lipopolysaccharide (LPS) is one of the most effective CRS inducers, which can activate macrophages to release cytokines, including tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), IL- 6 and chemokines. We used RT-PCR to detect the expression of representative cytokines in mouse and human cells at different concentrations of Trichomicin, Ebosin, and 1487B after LPS stimulation. The results showed that the expression of TNF-α, IL-1β, IL-6, and CXCL10 all increased after LPS stimulation. Among the various drugs, Trichomicin had the most obvious inhibitory effect on cytokine expression in vitro, and it was further verified in vivo that Trichomicin can improve the survival rate of mice stimulated with LPS. Finally, it was proved that Trichomicin inhibited the Stat3 and NF-κB pathways and reduced the phosphorylation of Stat3 and p65 after LPS stimulation, thereby inhibiting the response of macrophages to pro-inflammatory stimuli. The article clarified the inhibitory activity and mechanism of action of Trichomicin on CRS, and laid the foundation for the research on the anti-cytokine storm activity of microbial natural products.

Alterations in the number of motoneurons containing immunoreactive calcitonin gene-related peptide(CGRP)& choline acetyltransferase(ChAT) in the cervical spinal cord of the wobbler mouse during the development of the motoneuron disease

1995 ◽  
Vol 53 ◽  
pp. 970-971
Author(s):  
L. Vacca-Galloway ◽  
Y.Q. Zhang ◽  
P. Bose ◽  
S.H. Zhang
Keyword(s):  
Spinal Cord ◽  
Early Stage ◽  
Cervical Spinal Cord ◽  
Wild Type Mouse ◽  
Reflex Response ◽  
Mouse Strains ◽  
Behavioral Tests ◽  
Wobbler Mouse ◽  
Stage 4 ◽  
Stage 1

The Wobbler mouse (wr) has been studied as a model for inherited human motoneuron diseases (MNDs). Using behavioral tests for forelimb power, walking, climbing, and the “clasp-like reflex” response, the progress of the MND can be categorized into early (Stage 1, age 21 days) and late (Stage 4, age 3 months) stages. Age-and sex-matched normal phenotype littermates (NFR/wr) were used as controls (Stage 0), as well as mice from two related wild-type mouse strains: NFR/N and a C57BI/6N. Using behavioral tests, we also detected pre-symptomatic Wobblers at postnatal ages 7 and 14 days. The mice were anesthetized and perfusion-fixed for immunocytochemical (ICC) of CGRP and ChAT in the spinal cord (C3 to C5).Using computerized morphomety (Vidas, Zeiss), the numbers of IR-CGRP labelled motoneurons were significantly lower in 14 day old Wobbler specimens compared with the controls (Fig. 1). The same trend was observed at 21 days (Stage 1) and 3 months (Stage 4). The IR-CGRP-containing motoneurons in the Wobbler specimens declined progressively with age.

Automated high-resolution microscopy: the approaches so far

1987 ◽  
Vol 45 ◽  
pp. 58-61
Author(s):  
W. O. Saxton
Keyword(s):  
High Resolution ◽  
Early Stage ◽  
Automatic Recording ◽  
Microprocessor Control ◽  
Alternative Systems ◽  
Electron Image ◽  
Complete Automation ◽  
Analysis System ◽  
High Resolution Microscopy

Recent commercial microscopes with internal microprocessor control of all major functions have already demonstrated some of the benefits anticipated from such systems, such as continuous magnification, rotation-free diffraction and magnification, automatic recording of mutually registered focal series, and fewer control knobs. Complete automation of the focusing, stigmating and alignment of a high resolution microscope, allowing focal series to be recorded at preselected focus values as well, is still imminent rather than accomplished, however; some kind of image pick-up and analysis system, fed with the electron image via a TV camera, is clearly essential for this, but several alternative systems and algorithms are still being explored. This paper reviews the options critically in turn, and stresses the need to consider alignment and focusing at an early stage, and not merely as an optional extension to a basic proposal.

Direct observation of Fe-Al-Zn ternary intermetallic compound and its transformation during the early stage of hot-dip galvanizing

1993 ◽  
Vol 51 ◽  
pp. 1116-1117
Author(s):  
C. S. Lin ◽  
W. A. Chiou ◽  
M. Meshii
Keyword(s):  
Intermetallic Compound ◽  
Reaction Rate ◽  
Diffusion Rate ◽  
Early Stage ◽  
Zinc Bath ◽  
Steel Sheets ◽  
Direct Observations ◽  
Solid Iron ◽  
Iron And Zinc ◽  
Ternary Intermetallic Compound

The galvannealed steel sheets have received ever increased attention because of their excellent post-painting corrosion resistance and good weldability. However, its powdering and flaking tendency during press forming processes strongly impairs its performance. In order to optimize the properties of galvanneal coatings, it is critical to control the reaction rate between solid iron and molten zinc.In commercial galvannealing line, aluminum is added to zinc bath to retard the diffusion rate between iron and zinc by the formation of a thin layer of Al intermetallic compound on the surface of steel at initial hot-dip galvanizing. However, the form of this compound and its transformation are still speculated. In this paper, we report the direct observations of this compound and its transformation.The specimens were prepared in a hot-dip simulator in which the steel was galvanized in the zinc bath containing 0.14 wt% of Al at a temperature of 480 °C for 5 seconds and was quenched by liquid nitrogen.

Anisotropy of interfacial defects in the initial stage of MOVPE GaAs growth On Si

1990 ◽  
Vol 48 (4) ◽  
pp. 592-593
Author(s):  
C. Vannuffel ◽  
C. Schiller ◽  
J. P. Chevalier
Keyword(s):  
Early Stage ◽  
Threading Dislocations ◽  
Mbe Growth ◽  
Detailed Mechanism ◽  
Si Substrates ◽  
Initial Stage ◽  
Interfacial Defects ◽  
Interfacial Dislocations ◽  
Step Growth ◽  
Essential Problem

Recently, interest has focused on the epitaxy of GaAs on Si as a promising material for electronic applications, potentially for integration of optoelectronic devices on silicon wafers. The essential problem concerns the 4% misfit between the two materials, and this must be accommodated by a network of interfacial dislocations with the lowest number of threading dislocations. It is thus important to understand the detailed mechanism of the formation of this network, in order to eventually reduce the dislocation density at the top of the layers.MOVPE growth is carried out on slightly misoriented, (3.5°) from (001) towards , Si substrates. Here we report on the effect of this misorientation on the interfacial defects, at a very early stage of growth. Only the first stage, of the well-known two step growth process, is thus considered. Previously, we showed that full substrate coverage occured for GaAs thicknesses of 5 nm in contrast to MBE growth, where substantially greater thicknesses are required.

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