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Journal of Enzyme Inhibition and... Dec 2023Boronic acids/esters have recently emerged in the field of medicinal and pharmaceutical research due to their exceptional oxophilicity, low toxicity, and unique... (Review)
Review
Boronic acids/esters have recently emerged in the field of medicinal and pharmaceutical research due to their exceptional oxophilicity, low toxicity, and unique structure. They are known as potent enzyme inhibitors, cancer therapy capture agents, and can mimic certain types of antibodies to fight infections. They have been designed and developed into drugs, and this approach has emerged in the last 20 years. Five boronic acid drugs have been approved by the FDA and Health Canada, two of which are used to treat cancer, specifically multiple myeloma. The purpose of this review is to investigate boronic acid/ester derivatives as potential pharmaceutical agents as well as the mechanism of action. It will concentrate on six types of cancer: multiple myeloma, prostate cancer, breast cancer, lung cancer, cervical cancer, and colon cancer. Some newly developed boron-containing compounds have already demonstrated highly promising activities, but further investigation is required before final conclusions can be drawn.
Topics: Humans; Prodrugs; Esters; Multiple Myeloma; Boronic Acids; Boron Compounds
PubMed: 37318308
DOI: 10.1080/14756366.2023.2220084 -
Plants (Basel, Switzerland) Nov 2023Most pectic rhamnogalacturonan-II (RG-II) domains in plant cell walls are borate-bridged dimers. However, the sub-cellular locations, pH dependence, reversibility and... (Review)
Review
Most pectic rhamnogalacturonan-II (RG-II) domains in plant cell walls are borate-bridged dimers. However, the sub-cellular locations, pH dependence, reversibility and biocatalyst involvement in borate bridging remain uncertain. Experiments discussed here explored these questions, utilising suspension-cultured plant cells. In-vivo pulse radiolabelling showed that most RG-II domains dimerise extremely quickly (<4 min after biosynthesis, thus while still intraprotoplasmic). This tallies with the finding that boron withdrawal causes cell wall weakening within 10-20 min, and supports a previously proposed biological role for boron/RG-II complexes specifically at the wall/membrane interface. We also discuss RG-II monomer ↔ dimer interconversion as monitored in vitro using gel electrophoresis and a novel thin-layer chromatography method to resolve monomers and dimers. Physiologically relevant acidity did not monomerise dimers, thus boron bridge breaking cannot be a wall-loosening mechanism in 'acid growth'; nevertheless, recently discovered RG-II trimers and tetramers are unstable and may thus underpin reversible wall loosening. Dimerising monomers in vitro by B(OH) required the simultaneous presence of RG-II-binding 'chaperones': co-ordinately binding metals and/or ionically binding cationic peptides. Natural chaperones of the latter type include highly basic arabinogalactan protein fragments, e.g., KHKRKHKHKRHHH, which catalyse a reaction [2 RG-II + B(OH) → RG-II-B-RG-II], suggesting that plants can 'enzymically' metabolise boron.
PubMed: 38068557
DOI: 10.3390/plants12233921 -
Discover Nano Apr 2024For the development of nanofilters and nanosensors, we wish to know the impact of size on their geometric, electronic, and thermal stabilities. Using the semiempirical...
For the development of nanofilters and nanosensors, we wish to know the impact of size on their geometric, electronic, and thermal stabilities. Using the semiempirical tight binding method as implemented in the xTB program, we characterized Möbius boron-nitride and carbon-based nanobelts with different sizes and compared them to each other and to normal nanobelts. The calculated properties include the infrared spectra, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), the energy gap, the chemical potential, and the molecular hardness. The agreement between the peak positions from theoretical infrared spectra compared with experimental ones for all systems validates the methodology that we used. Our findings show that for the boron-nitride-based nanobelts, the calculated properties have an opposite monotonic relationship with the size of the systems, whereas for the carbon-based nanobelts, the properties show the same monotonic relationship for both types of nanobelts. Also, the torsion presented on the Möbius nanobelts, in the case of boron-nitride, induced an inhomogeneous surface distribution for the HOMO orbitals. High-temperature molecular dynamics also allowed us to contrast carbon-based systems with boron-nitride systems at various temperatures. In all cases, the properties vary with the increase in size of the nanobelts, indicating that it is possible to choose the desired values by changing the size and type of the systems. This work has many implications for future studies, for example our results show that carbon-based nanobelts did not break as we increased the temperature, whereas boron-nitride nanobelts had a rupture temperature that varied with their size; this is a meaningful result that can be tested when the use of more accurate simulation methods become practical for such systems in the future.
PubMed: 38589649
DOI: 10.1186/s11671-024-03967-0 -
Biomedicines Jun 2023The development of new methods increasing the biological effectiveness of proton therapy (PT) is of high interest in radiation oncology. The use of binary technologies,... (Review)
Review
The development of new methods increasing the biological effectiveness of proton therapy (PT) is of high interest in radiation oncology. The use of binary technologies, in which the damaging effect of proton radiation is further enhanced by the selective accumulation of the radiosensitizer in the target tissue, can significantly increase the effectiveness of radiation therapy. To increase the absorbed dose in a tumor target, proton boron capture therapy (PBCT) was proposed based on the reaction of proton capture on the B isotope with the formation of three α-particles. This review summarizes data on theoretical and experimental studies on the effectiveness and prospects of proton boron capture therapy.
PubMed: 37371822
DOI: 10.3390/biomedicines11061727 -
Beilstein Journal of Organic Chemistry 2024We confirm the previously revised stereochemistry of spiroviolene by X-ray crystallographically characterizing a hydrazone derivative of 9-oxospiroviolane, which is...
We confirm the previously revised stereochemistry of spiroviolene by X-ray crystallographically characterizing a hydrazone derivative of 9-oxospiroviolane, which is synthesized by hydroboration/oxidation of spiroviolene followed by oxidation of the resultant hydroxy group. An unexpected thermal boron migration occurred during the hydroboration process of spiroviolene that resulted in the production of a mixture of 1α-hydroxyspiroviolane, 9α- and 9β-hydroxyspiroviolane after oxidation. The assertion of the -orientation of the 19- and 20-methyl groups provided further support for the revised cyclization mechanism of spiroviolene.
PubMed: 38655555
DOI: 10.3762/bjoc.20.77 -
RSC Advances Jan 2024Boron nitride has gained wide-spread attention globally owing to its outstanding characteristics, such as a large surface area, high thermal resistivity, great... (Review)
Review
Boron nitride has gained wide-spread attention globally owing to its outstanding characteristics, such as a large surface area, high thermal resistivity, great mechanical strength, low density, and corrosion resistance. This review compiles state-of-the-art synthesis techniques, including mechanical exfoliation, chemical exfoliation, chemical vapour deposition (CVD), and green synthesis for the fabrication of hexagonal boron nitride and its composites, their structural and chemical properties, and their applications in hydrogen production and environmental remediation. Additionally, the adsorptive and photocatalytic properties of boron nitride-based nanocomposites for the removal of heavy metals, dyes, and pharmaceuticals from contaminated waters are discussed. Lastly, the scope of future research, including the facile synthesis and large-scale applicability of boron nitride-based nanomaterials for wastewater treatment, is presented. This review is expected to deliver preliminary knowledge of the present state and properties of boron nitride-based nanomaterials, encouraging the future study and development of these materials for their applications in various fields.
PubMed: 38259991
DOI: 10.1039/d3ra08323c -
Materials (Basel, Switzerland) Aug 2023The present analysis addresses the solidification and thermodynamic parameters involved during the solidification of aluminum (Al)-based alloys as presented in the... (Review)
Review
The present analysis addresses the solidification and thermodynamic parameters involved during the solidification of aluminum (Al)-based alloys as presented in the literature using different systems viz., binary aluminum-boron (Al-B) and aluminum-titanium (Al-Ti) systems, ternary aluminum-titanium-boron (Al-Ti-B) and aluminum-titanium-carbon (Al-Ti-C) systems, as well as taking into consideration the silicon-titanium-aluminide (Si-TiAl) interaction in Al-based alloys containing Si. The analysis is supported by recent metallographic evidence obtained by the authors on A356.2 alloys. The sections on thermodynamic aspects cover the different models proposed concerning nucleation and growth on a newly formed Al grain. The value of the recalescence parameter reduces gradually with the increase in the Ti added. At a level of 0.20 wt%, this parameter becomes zero. If the concentration of grain refiner exceeds a certain amount, the grain size becomes minimal. Another parameter to be considered is the interaction between the grain refiner and traces of other metals in the base alloy. For example, Al-4%B can react with traces of Ti that may exist in the base alloy, leading to the reaction between boron and titanium to form titanium diboride (TiB). Grain refinement is achieved primarily with TiB rather than aluminum diboride (AlB), or both, depending on the Ti content in the given alloy.
PubMed: 37629930
DOI: 10.3390/ma16165639 -
Pharmaceutics Aug 2023The presence of a large number of boron atoms in boron clusters make them attractive tools for the treatment of cancer using boron neutron capture therapy (BNCT). Since... (Review)
Review
The presence of a large number of boron atoms in boron clusters make them attractive tools for the treatment of cancer using boron neutron capture therapy (BNCT). Since the quantity of boron atoms present in the target cell directly affects the effectiveness of BNCT, the idea of gathering a high number of boron atoms in a single entity has emerged many years ago. In this perspective, using hyper-branched macromolecules such as dendrimers appears as an interesting solution. In this review, we will first present the synthesis of diverse dendritic entities (dendrimers, dendrons, and Janus dendrimers) that incorporate boron clusters, in particular carboranes, anywhere in their structure. Four parts of this review present the synthesis of dendrimers having boron clusters on the surface, or inside their structure, of dendrons and of Janus dendrimers, bearing boron clusters. Practically all these boronated dendritic structures were synthesized with the objective to study their biological properties, but in fact only a few of them have been tested against cancerous cells, and even a smaller number was tested in BNCT experiments. The biological experiments are discussed in the fifth part of this review. A good efficiency is generally observed with the boronated dendrimers, even in animal models, with an increase in their mean survival time (MST).
PubMed: 37631334
DOI: 10.3390/pharmaceutics15082117 -
RSC Advances Jun 2023To fill the knowledge gap for borophene, as the youngest member of the two-dimensional (2D) nanomaterials family, a facile, cost effective, scalable and reproducible...
To fill the knowledge gap for borophene, as the youngest member of the two-dimensional (2D) nanomaterials family, a facile, cost effective, scalable and reproducible fabrication route is still strongly required. Among so far studied techniques the potential of pure mechanical processes such as ball milling is not explored yet. Therefore, in this contribution, we explore the efficiency to exfoliate bulk boron into a few-layered borophene induced by mechanical energy in the planetary ball mill. It was revealed that the resulting flakes thickness and distribution can be controlled by (i) rotation speed (250-650 rpm), (ii) time of ball-milling (1-12 hours), and mass loading of bulk boron (1-3 g). Furthermore, the optimal conditions for the ball-milling process to induce efficient mechanical exfoliation of boron were determined to be 450 rpm, 6 hours, and 1 g (450 rpm_6 h_1 g), which resulted in the fabrication of regular and thin few-layered borophene flakes (∼5.5 nm). What is more, the mechanical energy induced during ball-milling, and the heat generated inside, affected the structure of borophene resulting in different crystalline phases. Besides being an additional and interesting discovery, it will also open up opportunities to investigate the relevance between the properties and the emerging phase. Structures labeled as β-rhombohedral, γ-orthorhombic, τ-B and the conditions under which they appear, have been described. Therefore, in our study, we open a new door to obtain a bulk quantity of few-layered borophene for further fundamental studies and practical potential assessment.
PubMed: 37283869
DOI: 10.1039/d3ra02400h -
Acta Crystallographica. Section E,... Nov 2023The title compound, CHBNSi (), is an asymmetric 1,2,3,6-tetra-hydro-1,2-aza-borinine consisting of a BN-substituted cyclo-hexa-diene analog with a -anthracenyl...
The title compound, CHBNSi (), is an asymmetric 1,2,3,6-tetra-hydro-1,2-aza-borinine consisting of a BN-substituted cyclo-hexa-diene analog with a -anthracenyl substituent. A ring-closing metathesis with subsequent substitution of the obtained BCl 1,2-aza-borinine using anthracenyl lithium yielded the title compound . The asymmetric unit ( = 8) belongs to the ortho-rhom-bic space group and shows an elongated N-C bond compared to previously reported BN-1,4-cyclo-hexa-diene [Abbey (2008 ▸) , 7250-7252]. The primarily contributing surface inter-actions are H⋯H and C⋯H/H⋯C (as elucidated by Hirshfeld surface analysis) which are dominated by van der Waals forces. Moreover, the non-aromatic BN heterocycle and the protecting group exhibit intra- and inter-molecular C-H⋯π inter-actions, respectively, with the anthracenyl substituent.
PubMed: 37936862
DOI: 10.1107/S2056989023008381