China
Africa
Explore chapters and articles related to this topic
Bio-Implants Derived from Biocompatible and Biodegradable Biopolymeric Materials
Published in P. Mereena Luke, K. R. Dhanya, Didier Rouxel, Nandakumar Kalarikkal, Sabu Thomas, Advanced Studies in Experimental and Clinical Medicine, 2021
Cooper et al. [13] have developed polymers with high molecular weights. It also gives high tensile properties and melts processability similar to synthetic polymers. Hence can be used as similar as radiation sterilizable aromatic polyanhydride. Nicholas et al. [6] have developed a new route for the preparation of fluorescent bioconjugates by living radical polymerization using protein-derived macro initiators. These fluorescent bioconjugates can be easily traceable in biological environments, during biomedical assays. Cycloaddition reactions have been explored by Grayson et al. [14] to prepare macrocyclic poly(hydroxyl styrene). The presence of a phenolic hydroxyl group on each repeat unit in the cyclic polymer gives better scope for attachment of bioactive counterparts. The cyclization technique to have a wider application for preparing a wide range of functionalized macrocycles. Smith and coworkers [15] found poly(N-vinylpyrrolidinone) hydrogels functionalized with drug molecules as promising hydrogels for sustained release of drugs over several days.
Biotransformation of Monoterpenoids by Microorganisms, Insects, and Mammals
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Yoshiaki Noma, Yoshinori Asakawa
A research group in Czechoslovakia patented the cyclization of citronellal (261) with subsequent hydrogenation to menthol by Penicillium digitatum in 1952. Unfortunately the optical purities of the intermediates pulegol and isopulegol were not determined, and presumably the resulting menthol was a mixture of enantiomers. Therefore, it cannot be excluded that this extremely interesting cyclization is the result of a reaction primarily catalyzed by the acidic fermentation conditions and only partially dependent on enzymatic reactions (Babcka et al., 1956) (Figure 22.6).
Aliphatic and Aromatic Hydrocarbons
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
In general, the toxicity and reactivity of aliphatic and alicyclic HCs are low. For instance, gaseous compounds have properties similar to those of pulmonary irritants or simple asphyxiants. The degree of cyclization or unsaturation does not correlate with toxicity, and they usually produce anesthetic effects at very high ambient concentrations. As with the simple asphyxiants, therefore, their toxicity is limited to the amount of substituted oxygen.
Design and statistical optimisation of emulsomal nanoparticles for improved anti-SARS-CoV-2 activity of N-(5-nitrothiazol-2-yl)-carboxamido candidates: in vitro and in silico studies
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Ahmed A. Al-Karmalawy, Dalia S. El-Gamil, Rabeh El-Shesheny, Marwa Sharaky, Radwan Alnajjar, Omnia Kutkat, Yassmin Moatasim, Mohamed Elagawany, Sara T. Al-Rashood, Faizah A. Binjubair, Wagdy M. Eldehna, Ayman M. Noreddin, Mohamed Y. Zakaria
Chain cyclisation is one of the most commonly adopted drug design strategies as it may enhance binding affinity and/or stabilise target binding patterns61. Herein, we investigated the effect of cyclising the benzyl carbamate NH with the α-carbon via a propyl spacer forming the conformationally restricted pyrrolidine moiety (compound 3f). Unfortunately, such a rigidification did not improve the anti-SARS-CoV-2 activity where 3f demonstrated an IC50 of 6.22 μg/mL which is almost fourfold higher than compound 3d having analogous side chain carbons. This could be attributed to a cyclisation-induced twist in the main scaffold that led to the deviation of compound 3f away from key residues in the CYS-HIS dyad of the SARS-CoV-2 Mpro active site. Moreover, the capability to form an H-bond with the crucial amino acid GLU_166 was lost by cyclisation (supplementary material, Figure S2), further contributing to the observed diminished activity of compound 3f.
Antimicrobial peptides and other peptide-like therapeutics as promising candidates to combat SARS-CoV-2
Published in Expert Review of Anti-infective Therapy, 2021
Masoumeh Sadat Mousavi Maleki, Mosayeb Rostamian, Hamid Madanchi
Peptidomimetics are designed based on small protein-like chains or small molecules that mimic the behavior of a peptide and have regulated molecular properties, such as high stability or biological activity. The use of peptidomimetics is a very powerful strategy for designing small molecule-based drugs as enzyme inhibitors or receptor ligands [106]. These compounds mimic a natural peptide or a protein of the viruses and have the ability to interact with their biological targets and produce the same biological effects [107]. There are different types of changes to create peptidomimetics with improved drug properties, including local changes, such as the binding of nonstandard amino acids, and general changes, such as forming a circular end in polypeptide chains during a cyclization process. Cyclization is one of the most common strategies used to convert peptides into drugs and pharmacologically active agents [108].
An update on the therapeutic potential of calpain inhibitors: a patent review
Published in Expert Opinion on Therapeutic Patents, 2020
Proteolytic enzymes such as calpain generally bind to the extended-strand conformation of substrates, which usually requires 4–5 residues for sequence recognition [26]. Therefore, a successful approach to protease inhibitor design is to lock the recognition sequence into a specific conformation within a cyclic peptide. This concept has been explored to design calpain inhibitors [27]. The advantages of cyclization include reduced entropic penalty for binding to the target protein [28,29] and enhanced stability to proteolytic degradation in vivo [30]. Low et al. [31] applied the concept to designed calpain inhibitors based on calpastatin, which is a highly specific natural inhibitor of calpain [32]. The group proposed that peptidomimetics that incorporate the conserved β-turn residues (i.e., KLGE) of calpastatin in the region where it binds to the active site of calpain should display calpastatin-like specificity and potency.