Relationship between porphyrin aggregation and formation of porphyrin ring structures in poly(n-alkyl methacrylate)/porphyrin blends

Polymer ◽  
2016 ◽  
Vol 102 ◽  
pp. 136-142 ◽  
Author(s):  
J.R. Tozoni ◽  
N.M. Barbosa Neto ◽  
C.A. Ribeiro ◽  
W.M. Pazin ◽  
A.S. Ito ◽  
...  
Keyword(s):  
Porphyrin Ring ◽  
Alkyl Methacrylate ◽  
Ring Structures ◽  
Porphyrin Aggregation

scholarly journals Classic highlights in porphyrin and porphyrinoid total synthesis and biosynthesis

2021 ◽  
Author(s):  
Mathias O. Senge ◽  
Natalia N. Sergeeva ◽  
Karl J. Hale
Keyword(s):  
Total Synthesis ◽  
Porphyrin Ring ◽  
Selective Functionalization ◽  
Porphyrin Synthesis

The development of porphyrin synthesis is illustrated, using classic and modern-day examples, which attempt to provide insights, including mechanistic ones, into the most used methods for porphyrin ring-construction and selective functionalization.

scholarly journals Nanoformulations for Delivery of Pentacyclic Triterpenoids in Anticancer Therapies

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1764
Author(s):  
Anna Kaps ◽  
Paweł Gwiazdoń ◽  
Ewa Chodurek
Keyword(s):  
Water Solubility ◽  
Biological Activities ◽  
Premature Mortality ◽  
Delivery Systems ◽  
Pentacyclic Triterpenoids ◽  
Anticancer Properties ◽  
Oncological Patients ◽  
Antitumor Potential ◽  
Ring Structures

The search for safe and effective anticancer therapies is one of the major challenges of the 21st century. The ineffective treatment of cancers, classified as civilization diseases, contributes to a decreased quality of life, health loss, and premature mortality in oncological patients. Many natural phytochemicals have anticancer potential. Pentacyclic triterpenoids, characterized by six- and five-membered ring structures, are one of the largest class of natural metabolites sourced from the plant kingdom. Among the known natural triterpenoids, we can distinguish lupane-, oleanane-, and ursane-types. Pentacyclic triterpenoids are known to have many biological activities, e.g., anti-inflammatory, antibacterial, hepatoprotective, immunomodulatory, antioxidant, and anticancer properties. Unfortunately, they are also characterized by poor water solubility and, hence, low bioavailability. These pharmacological properties may be improved by both introducing some modifications to their native structures and developing novel delivery systems based on the latest nanotechnological achievements. The development of nanocarrier-delivery systems is aimed at increasing the transport capacity of bioactive compounds by enhancing their solubility, bioavailability, stability in vivo and ensuring tumor-targeting while their toxicity and risk of side effects are significantly reduced. Nanocarriers may vary in sizes, constituents, shapes, and surface properties, all of which affect the ultimate efficacy and safety of a given anticancer therapy, as presented in this review. The presented results demonstrate the high antitumor potential of systems for delivery of pentacyclic triterpenoids.

scholarly journals The Long-Lasting Story of One Sensor Development: From Novel Ionophore Design toward the Sensor Selectivity Modeling and Lifetime Improvement

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1401
Author(s):  
Larisa Lvova ◽  
Donato Monti ◽  
Corrado Di Natale ◽  
Roberto Paolesse
Keyword(s):  
Anion Exchanger ◽  
Specific Interaction ◽  
Spectroscopic Studies ◽  
Polymeric Membranes ◽  
Polymeric Membrane ◽  
Active Components ◽  
Nitrite Ion ◽  
Working Mechanism ◽  
Axial Coordination ◽  
Porphyrin Aggregation

The metalloporphyrin ligand bearing incorporated anion-exchanger fragment, 5-[4-(3-trimethylammonium)propyloxyphenyl]-10,15,20-triphenylporphyrinate of Co(II) chloride, CoTPP-N, has been tested as anion-selective ionophore in PVC-based solvent polymeric membrane sensors. A plausible sensor working mechanism includes the axial coordination of the target anion on ionophore metal center followed by the formed complex aggregation with the second ionophore molecule through positively charged anion-exchanger fragment. The UV-visible spectroscopic studies in solution have revealed that the analyte concentration increase induces the J-type porphyrin aggregation. Polymeric membranes doped with CoTPP-N showed close to the theoretical Nernstian response toward nitrite ion, preferably coordinated by the ionophore, and were dependent on the presence of additional membrane-active components (lipophilic ionic sites and ionophore) in the membrane phase. The resulting selectivity was a subject of specific interaction and/or steric factors. Moreover, it was demonstrated theoretically and confirmed experimentally that the selection of a proper ratio of ionophore and anionic additive can optimize the sensor selectivity and lifetime.

scholarly journals Achieving selectivity in porphyrin bromination through a DoE-driven optimization under continuous flow conditions

2020 ◽  
Author(s):  
Paolo Zardi ◽  
Michele Maggini ◽  
Tommaso Carofiglio
Keyword(s):  
Reaction Time ◽  
Design Of Experiment ◽  
Continuous Flow ◽  
Optimization Process ◽  
Porphyrin Ring ◽  
Flow Conditions ◽  
Reaction Parameters ◽  
Synthetic Procedure ◽  
Relevant Factors ◽  
Post Functionalization

AbstractThe post-functionalization of porphyrins through the bromination in β position of the pyrrolic rings is a relevant transformation because the resulting bromoderivatives are useful synthons to covalently link a variety of chemical architectures to a porphyrin ring. However, single bromination of porphyrins is a challenging reaction for the abundancy of reactive β-pyrrolic positions in the aromatic macrocycle. We herein report a synthetic procedure for the efficient preparation of 2-bromo-5,10,15,20-tetraphenylporphyrin (1) under continuous flow conditions. The use of flow technology allows to reach an accurate control over critical reaction parameters such as temperature and reaction time. Furthermore, by performing the optimization process through a statistical DoE (Design of Experiment) approach, these parameters could be properly adjusted with a limited number of experiments. This process led us to a better understanding of the relevant factors that govern porphyrins monobromination and to obtain compound 1 with an unprecedent 80% yield.

Unprecedented Reactivity of γ‐Amino Cyclopentenone Enables Diversity‐Oriented Access to Functionalized Indoles and Indole‐Annulated Ring Structures

2021 ◽  
Vol 60 (16) ◽  
pp. 8808-8812
Author(s):  
Chenna Jagadeesh ◽  
Biplab Mondal ◽  
Sourav Pramanik ◽  
Dinabandhu Das ◽  
Jaideep Saha
Keyword(s):  
Ring Structures

scholarly journals A plant endophyte Staphylococcus hominis strain MBL_AB63 produces a novel lantibiotic, homicorcin and a position one variant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Aftab Uddin ◽  
Shammi Akter ◽  
Mahbuba Ferdous ◽  
Badrul Haidar ◽  
Al Amin ◽  
...  
Keyword(s):  
Gene Clusters ◽  
Antimicrobial Activities ◽  
Whole Genome Sequence ◽  
Antimicrobial Substances ◽  
The Core ◽  
Rp Hplc ◽  
Ring Structures ◽  
Core Peptide ◽  
Staphylococcus Hominis ◽  
Epilancin 15X

AbstractHere we report a jute endophyte Staphylococcus hominis strain MBL_AB63 isolated from jute seeds which showed promising antimicrobial activity against Staphylococcus aureus SG511 when screening for antimicrobial substances. The whole genome sequence of this strain, annotated using BAGEL4 and antiSMASH 5.0 to predict the gene clusters for antimicrobial substances identified a novel antimicrobial peptide cluster that belongs to the class I lantibiotic group. The predicted lantibiotic (homicorcin) was found to be 82% similar to a reported peptide epicidin 280 having a difference of seven amino acids at several positions of the core peptide. Two distinct peaks obtained at close retention times from a RP-HPLC purified fraction have comparable antimicrobial activities and LC–MS revealed the molecular mass of these peaks to be 3046.5 and 3043.2 Da. The presence of an oxidoreductase (homO) similar to that of epicidin 280- associated eciO or epilancin 15X- associated elxO in the homicorcin gene cluster is predicted to be responsible for the reduction of the first dehydrated residue dehydroalanine (Dha) to 2-hydroxypropionate that causes an increase of 3 Da mass of homicorcin 1. Trypsin digestion of the core peptide and its variant followed by ESI–MS analysis suggests the presence of three ring structures, one in the N-terminal and other two interlocking rings at the C-terminal region that remain undigested. Homicorcin exerts bactericidal activity against susceptible cells by disrupting the integrity of the cytoplasmic membrane through pore formation as observed under FE-SEM.

scholarly journals Serendipitous crystallization and structure determination of bacterioferritin from Achromobacter

2018 ◽  
Vol 74 (9) ◽  
pp. 558-566
Author(s):  
Abhisek Dwivedy ◽  
Bhavya Jha ◽  
Khundrakpam Herojit Singh ◽  
Mohammed Ahmad ◽  
Anam Ashraf ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Iron Homeostasis ◽  
Critical Role ◽  
Porphyrin Ring ◽  
Opportunistic Pathogens ◽  
Complex Design ◽  
Archaeal Species ◽  
Ferroxidase Center ◽  
Mycobacterial Protein

Bacterioferritins (Bfrs) are ferritin-like molecules with a hollow spherical 24-mer complex design that are unique to bacterial and archaeal species. They play a critical role in storing iron(III) within the complex at concentrations much higher than the feasible solubility limits of iron(III), thus maintaining iron homeostasis within cells. Here, the crystal structure of bacterioferritin from Achromobacter (Ach Bfr) that crystallized serendipitously during a crystallization attempt of an unrelated mycobacterial protein is reported at 1.95 Å resolution. Notably, Fe atoms were bound to the structure along with a porphyrin ring sandwiched between the subunits of a dimer. Furthermore, the dinuclear ferroxidase center of Ach Bfr has only a single iron bound, in contrast to the two Fe atoms in other Bfrs. The structure of Ach Bfr clearly demonstrates the substitution of a glutamate residue, which is involved in the interaction with the second Fe atom, by a threonine and the consequent absence of another Fe atom there. The iron at the dinuclear center has a tetravalent coordination, while a second iron with a hexavalent coordination was found within the porphyrin ring, generating a heme moiety. Achromobacter spp. are known opportunistic pathogens; this structure enhances the current understanding of their iron metabolism and regulation, and importantly will be useful in the design of small-molecule inhibitors against this protein through a structure-guided approach.

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