Microtubule configurations and nuclear DNA synthesis during initiation of suspensor-bearing embryos from Brassica napus cv. Topas microspores

In the new Brassica napus microspore culture system, wherein embryos with suspensors are formed, ab initio mimics zygotic embryogenesis. The system provides a powerful in vitro tool for studying the diverse developmental processes that take place during early stages of plant embryogenesis. Here, we studied in this new culture system both the temporal and spatial distribution of nuclear DNA synthesis places and the organization of the microtubular (MT) cytoskeleton, which were visualized with a refined whole mount immunolocalization technology and 3D confocal laser scanning microscopy. A ‘mild’ heat stress induced microspores to elongate, to rearrange their MT cytoskeleton and to re-enter the cell cycle and perform a predictable sequence of divisions. These events led to the formation of a filamentous suspensor-like structure, of which the distal tip cell gave rise to the embryo proper. Cells of the developing pro-embryo characterized endoplasmic (EMTs) and cortical microtubules (CMTs) in various configurations in the successive stages of the cell cycle. However, the most prominent changes in MT configurations and nuclear DNA replication concerned the first sporophytic division occurring within microspores and the apical cell of the pro-embryo. Microspore embryogenesis was preceded by pre-prophase band formation and DNA synthesis. The apical cell of the pro-embryo exhibited a random organization of CMTs and, in relation to this, isotropic expansion occurred, mimicking the development of the apical cell of the zygotic situation. Moreover, the apical cell entered the S phase shortly before it divided transversally at the stage that the suspensor was 3–8 celled

Toward Better Understanding of Isomorphism of Glycyrrhizic Acid and Its Mono- and Dibasic Salts

X-ray crystallography reveals that crystal structures of mono- and diammonium, mono- and dipotassium, and mono- and dicesium glycyrrhizinates are isomorphic, and they are also isomorphic with the earlier reported structure of glycyrrhizic acid. Despite differences in the ionization state of glycyrrhizic acid and the type and size of counterions, basic supramolecular organization in the crystals remains practically unchanged. The aggregation of amphiphilic glycyrrhizinate anions results in the structure with well separated hydrophobic (aglycone) and hydrophilic (diglucuronic unit, i.e., glycone) areas. In the glycyrrhizinate salts the hydrophilic area in the form of a flat two-dimensional platform consists of mono- or dideprotonated diglucuronic units arranged into zigzag chains. Solvent molecules and cations are an integral part of this hydrophilic area consolidating the platform by hydrogen bonds and ion–dipole interactions. Monovalent cations are located at the sites that in the glycyrrhizic acid structure are occupied by tetrahedrally hydrogen-bonded water molecules. Since they do not bind <i>syn</i> to the carboxylic or carboxylate groups of the diglucuronic units, the generation of the characteristic zigzag chains is possible, regardless of the ionization state of glycyrrhizic acid

Toward Better Understanding of Isomorphism of Glycyrrhizic Acid and Its Mono- and Dibasic Salts

X-ray crystallography reveals that crystal structures of mono- and diammonium, mono- and dipotassium, and mono- and dicesium glycyrrhizinates are isomorphic, and they are also isomorphic with the earlier reported structure of glycyrrhizic acid. Despite differences in the ionization state of glycyrrhizic acid and the type and size of counterions, basic supramolecular organization in the crystals remains practically unchanged. The aggregation of amphiphilic glycyrrhizinate anions results in the structure with well separated hydrophobic (aglycone) and hydrophilic (diglucuronic unit, i.e., glycone) areas. In the glycyrrhizinate salts the hydrophilic area in the form of a flat two-dimensional platform consists of mono- or dideprotonated diglucuronic units arranged into zigzag chains. Solvent molecules and cations are an integral part of this hydrophilic area consolidating the platform by hydrogen bonds and ion–dipole interactions. Monovalent cations are located at the sites that in the glycyrrhizic acid structure are occupied by tetrahedrally hydrogen-bonded water molecules. Since they do not bind <i>syn</i> to the carboxylic or carboxylate groups of the diglucuronic units, the generation of the characteristic zigzag chains is possible, regardless of the ionization state of glycyrrhizic acid

Hot-Melt Extrusion as an Effective Technique for Obtaining an Amorphous System of Curcumin and Piperine with Improved Properties Essential for Their Better Biological Activities

Poor bioavailability hampers the use of curcumin and piperine as biologically active agents. It can be improved by enhancing the solubility as well as by using bioenhancers to inhibit metabolic transformation processes. Obtaining an amorphous system of curcumin and piperine can lead to the overcoming of these limitations. Hot-melt extrusion successfully produced their amorphous systems, as shown by XRPD and DSC analyses. Additionally, the presence of intermolecular interactions between the components of the systems was investigated using the FT-IR/ATR technique. The systems were able to produce a supersaturation state as well as improve the apparent solubilities of curcumin and piperine by 9496- and 161-fold, respectively. The permeabilities of curcumin in the GIT and BBB PAMPA models increased by 12578- and 3069-fold, respectively, whereas piperine’s were raised by 343- and 164-fold, respectively. Improved solubility had a positive effect on both antioxidant and anti-butyrylcholinesterase activities. The best system suppressed 96.97 ± 1.32% of DPPH radicals, and butyrylcholinesterase activity was inhibited by 98.52 ± 0.87%. In conclusion, amorphization remarkably increased the dissolution rate, apparent solubility, permeability, and biological activities of curcumin and piperine

Amorphous Solid Dispersion of Hesperidin with Polymer Excipients for Enhanced Apparent Solubility as a More Effective Approach to the Treatment of Civilization Diseases

The present study reports amorphous solid dispersions (ASDs) of hesperidin (Hes) prepared by ball milling to improve its solubility and apparent solubility over the unmodified compound. The carriers were Soluplus® (Sol), alginate sodium (SA), and hydroxypropylmethylcellulose (HPMC). XRPD analysis confirmed full amorphization of all binary systems in 1:5 w/w ratio. One glass transition (Tg) observed in DSC thermograms of hesperidin:Soluplus® (Hes:Sol) and hesperidin:HPMC (Hes:HPMC) 1:5 w/w systems confirmed complete miscibility. The mathematical model (Gordon–Taylor equation) indicates that the obtained amorphous systems are characterized by weak interactions. The FT-IR results confirmed that hydrogen bonds are responsible for stabilizing the amorphous state of Hes. Stability studies indicate that the strength of these bonds is insufficient to maintain the amorphous state of Hes under stress conditions (25 °C and 60 °C 76.4% RH). HPLC analysis suggested that the absence of degradation products indicates safe hesperidin delivery systems. The solubility and apparent solubility were increased in all media (water, phosphate buffer pH 6.8 and HCl (0.1 N)) compared to the pure compound. Our study showed that all obtained ASDs are promising systems for Hes delivery, wherein Hes:Sol 1:5 w/w has the best solubility (about 300-fold in each media) and apparent solubility (about 70% in phosphate buffer pH 6.8 and 63% in HCl)

Supramolecular Organization of Neutral and Ionic Forms of Pharmaceutically Relevant Glycyrrhizic AcidAmphiphile Self-Assembly and Inclusion of Small Drug Molecules

The first structural characterization of glycyrrhizic acid, its monoammonium salt (AGA), and the complex of the salt with <i>p</i>-aminobenzoic acid in the solid state is reported. X-ray crystallography reveals that neutral and ionic forms of GA have similar supramolecular organization, with aglycon groups protruding from the 2D hydrogen-bonded sugar platform. Interpenetration of these assemblies leads to the generation of intersecting channels where solvent and guest molecules are enclosed. It is worth noting that small solvent molecules or cations can functionally replace three water molecules which are an integral part of the sugar platform in GA. The crystal structures indicate the drug and cation binding sites and explain the similar properties of glycyrrhizic acid and its salts. The presented structures provide information about the supramolecular organization of amphiphilic GA molecule in the solid state, giving a guide into a possible aggregation mode in gels and solutions

Supramolecular Organization of Neutral and Ionic Forms of Pharmaceutically Relevant Glycyrrhizic AcidAmphiphile Self-Assembly and Inclusion of Small Drug Molecules

The first structural characterization of glycyrrhizic acid, its monoammonium salt (AGA), and the complex of the salt with <i>p</i>-aminobenzoic acid in the solid state is reported. X-ray crystallography reveals that neutral and ionic forms of GA have similar supramolecular organization, with aglycon groups protruding from the 2D hydrogen-bonded sugar platform. Interpenetration of these assemblies leads to the generation of intersecting channels where solvent and guest molecules are enclosed. It is worth noting that small solvent molecules or cations can functionally replace three water molecules which are an integral part of the sugar platform in GA. The crystal structures indicate the drug and cation binding sites and explain the similar properties of glycyrrhizic acid and its salts. The presented structures provide information about the supramolecular organization of amphiphilic GA molecule in the solid state, giving a guide into a possible aggregation mode in gels and solutions

THE POSSIBILITY OF USING X-RAY POWDER DIFFRACTION, INFRARED AND RAMAN SPECTROSCOPY IN THE STUDY OF THE IDENTIFICATION OF STRUCTURAL POLYMORPHS OF ACETAMINOPHEN

Paracetamol (acetaminophen), a pain-killer with antipyretic properties, shows structural polymorphism. It occurs in three polymorphic forms: monoclinic, orthorhombic, and unstable form III. In the study, the commercially available samples of paracetamol (P1 and P2) were examined using X-ray powder diffraction, infrared, and Raman spectroscopy. Results demonstrated that all of the methods defined polymorphic forms of paracetamol in the samples. However, only Raman spectroscopy and PXRD methods detected impurities in the sample P1. These methods transpired to be more sensitive than the FT-IR method, which identified samples of paracetamol as one structural form (monoclinic polymorph). Moreover, the Raman spectroscopy identified impurities in the form P1 as changes in the crystalline form

Synthesis, immunosuppressive properties, mechanism of action and X-ray analysis of a new class of isoxazole derivatives

In the search for potential therapeutics, isoxazole derivatives are still objects of interest. Previously described immunoregulatory properties of 5-amino-3-methyl-4-isoxazolecarboxylic acid (AC) benzylamides prompted us to synthesize a new class of compounds of immunotropic activity. A series of new compounds containing the isoxazole moiety were synthesized using Passerini three-component reaction. The effects on phytohemagglutinin A (PHA)-induced proliferation of human peripheral blood mononuclear cells (PBMC), production of tumor necrosis factor alpha (TNF α) in human whole blood cultures stimulated with lipopolysaccharide (LPS) and two-way mixed lymphocyte reaction (MLR) of PBMC, were investigated. Also, the effect of 1-(cyclohexylcarbamoyl)cyclohexyl 5-amino-3-methylisoxazole-4-carboxylate (PUB1) on the expression of signaling molecules associated with cell apoptosis in Jurkat cells was also determined. The results showed that the compounds inhibited to various degree mitogen-induced PBMC proliferation in a dose-dependent manner and TNF α production at 10 μg/ml. PUB1 compound, selected on the basis of its strongest antiproliferative activity, was also shown to inhibit MLR. The molecular data suggest that immunosuppressive action of PUB1 depended on induction of Fas and elevation of caspase 8 expression. In summary, we revealed immunosuppressive properties of a new class of isoxazoles and established the mechanism of action of a representative PUB1 compound