Synthesis, Characterization and Crystal Structure of Samarium(III)-(E)-1-phenyl-N-(4H-1,2,4-triazol-4-yl)methanimine Complex

Samarium-benzylidene Schiff base adduct with the formula [Sm(NO3)3(H2O)3].2L (L= (E)-1-phenyl-N-(4H-1,2,4-triazol-4-yl) methanimine) (1) has been prepared, with two water molecules bonded to the samarium center form hydrogen bond with three molecules of title Schiff base through nitrogen atoms of the triazole rings. The chemical structure was confirmed by means of single-crystal X-ray diffraction (scXRD), FT-IR, electrical conductivity, thermogravimetric analysis (TGA), mass spectrometry and elemental analysis. The title complex 1 crystallizes in the triclinic P-1 space group. The unit cell parameters are a = 10.4045(1) Å, b = 12.5403(1) Å, c = 12.5477(2) Å,  = 96.668(1)o,  = 110.810(1)o,  = 111.567(1)o, V = 1.788 Å3, Z = 2, Rgt(F) = 0.0223, wRref(F2) = 0.0576. The samarium ion is in a distorted capped square antiprism environment, coordinated by three bidentate nitrates and three coordination water molecules. The [Sm(H2O)3(NO3)3] complex and the (E)-1-phenyl-N-(4H-1,2,4-triazol-4-yl)methanimine) moiety (L) are held together via hydrogen interactions to form a 2-D supramolecular framework. It is a non-electrolyte as indicated by its molar conductivity (ΛM= 10.1 S cm2 mol-1) in MeOH at 1.0 mM. The mass spectral results confirm the suggested structure of the investigated adduct.

Inhibition of Butyrylcholinesterase and Human Monoamine Oxidase-B by the Coumarin Glycyrol and Liquiritigenin Isolated from Glycyrrhiza uralensis

Eight compounds were isolated from the roots of Glycyrrhiza uralensis and tested for cholinesterase (ChE) and monoamine oxidase (MAO) inhibitory activities. The coumarin glycyrol (GC) effectively inhibited butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) with IC50 values of 7.22 and 14.77 µM, respectively, and also moderately inhibited MAO-B (29.48 µM). Six of the other seven compounds only weakly inhibited AChE and BChE, whereas liquiritin apioside moderately inhibited AChE (IC50 = 36.68 µM). Liquiritigenin (LG) potently inhibited MAO-B (IC50 = 0.098 µM) and MAO-A (IC50 = 0.27 µM), and liquiritin, a glycoside of LG, weakly inhibited MAO-B (>40 µM). GC was a reversible, noncompetitive inhibitor of BChE with a Ki value of 4.47 µM, and LG was a reversible competitive inhibitor of MAO-B with a Ki value of 0.024 µM. Docking simulations showed that the binding affinity of GC for BChE (−7.8 kcal/mol) was greater than its affinity for AChE (−7.1 kcal/mol), and suggested that GC interacted with BChE at Thr284 and Val288 by hydrogen bonds (distances: 2.42 and 1.92 Å, respectively) beyond the ligand binding site of BChE, but that GC did not form hydrogen bond with AChE. The binding affinity of LG for MAO-B (−8.8 kcal/mol) was greater than its affinity for MAO-A (−7.9 kcal/mol). These findings suggest GC and LG should be considered promising compounds for the treatment of Alzheimer’s disease with multi-targeting activities.

Inhibition of Butyrylcholinesterase by Glycyrol, a Coumarin, Isolated from Glycyrrhiza Uralensis

Eight compounds were isolated from the roots of Glycyrrhiza uralensis and tested for cholinesterase (ChE) and monoamine oxidase (MAO) inhibitory activities. Glycyrol (GC) effectively inhibited butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) with IC50 values of 7.22 and 14.77 µM, respectively, and also moderately inhibited MAO-B (29.48 µM). Six of the other seven compounds only weakly inhibited AChE and BChE, whereas liquiritin apioside moderately inhibited AChE (IC50 = 36.68 µM). Liquiritigenin (LG) potently inhibited MAO-B (IC50 = 0.098 µM) and MAO-A (IC50 = 0.27 µM), and liquiritin, a glycoside of LG, weakly inhibited MAO-B (> 40 µM). GC was a reversible, noncompetitive inhibitor of BChE with a Ki value of 4.47 µM, and LG was a reversible competitive inhibitor of MAO-B with a Ki value of 0.024 µM. Docking simulations showed that the binding affinity of GC for BChE (-7.8 kcal/mol) was greater than its affinity for AChE (-7.1 kcal/mol), and suggested that GC interacted with BChE at Thr284 and Val288 by hydrogen bonds (distances: 2.42 and 1.92 Å, respectively) beyond the ligand binding site of BChE, but that GC did not form hydrogen bond with AChE. The binding affinity of LG for MAO-B (-8.8 kcal/mol) was greater than its affinity for MAO-A (-7.9 kcal/mol). These findings suggest GC and LG should be considered promising compounds for the treatment of Alzheimer’s disease with multi-targeting activities.

A facile synthesis of soluble polyimides with high glass transition temperature and excellent mechanical properties due to intermolecular hydrogen bonds

An unsymmetrical heterocyclic diamine monomer containing proton donor (–NH–), 2-(4-aminophenyl)-5-aminobenzimidazole (PABZ), which can form hydrogen bond interactions with carbonyl functional group, was copolymerized with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (TFMB) through two-step synthetic methods to obtain a series of homo- and co-polyimide (PI). The corresponding homo- and co-PI both exhibited good solubility in aprotic polar solvents, such as N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N, N-dimethylformamide, pyridine, and dimethyl sulfoxide. In addition, the PI-containing PABZ units showed excellent tensile strength ranging from 83 to 164 MPa, 130–260% higher than 6FDA/TFMB homo-PIa films. These PIs, especially PABZ/6FDA, showed very high glass transition temperatures, 430°C.

Antioxidant Activity and Neuroprotective Activity of Stilbenoids in Rat Primary Cortex Neurons via the PI3K/Akt Signalling Pathway

Antioxidant activity and neuroprotective activity of three stilbenoids, namely, trans-4-hydroxystilbene (THS), trans-3,5,4′-trihydroxy-stilbene (resveratrol, RES), and trans-3′,4′,3,5-tetrahydroxy-stilbene (piceatannol, PIC), against β-amyloid (Aβ)-induced neurotoxicity in rat primary cortex neurons were evaluated. THS, RES, and PIC significantly scavenged DPPH• and •OH radicals. All three stilbenoids were able to inhibit Aβ neurotoxicity by decreasing intracellular reactive oxygen species (ROS) via the PI3K/Akt signalling pathway. Specifically, stilbenoids significantly promoted Akt phosphorylation; suppressed Bcl-2/Bax expression; and inhibited caspase-9, caspase-3, and PARP cleavage. Molecular docking between stilbenoids with Akt indicated that stilbenoids could form hydrogen bond interactions with the COOH-terminal region of Akt. Additionally, the neuroprotective activity of stilbenoids correlated with the number and position of hydroxyl groups. The lack of meta-dihydroxyl groups on THS did not affect its neuroprotective activity in comparison with RES, whereas the ortho-dihydroxyl moiety on PIC significantly enhanced neuroprotective activity. These results provide new insights into the correlation between the biological activity and chemical structure of stilbenoids.

Extra ordinary properties and importance of water

Life originated from water. It is a universal solvent. Useless and toxic materials are excreted from body through water. Many compounds form hydrogen bond with water and are soluble in water. Water is a polar solvent. Due to this property of water, many electrolyte dissolve in it. One water molecule is bonded with four water molecule due to hydrogen bond. Water maintains body temperature and helps to maintain various metabolic activities of body.

Amino-Modified Hydrogen-Bonding Resin and its Adsorption on Berberine

A hydrogen-bond donor resin HX was obtained by modifying resin H103 . The adsorption effect of resin HX on berberine was determined. The adsorbing kinetic and dynamic mechanisms of resin HX and resin H103 was compared. The results showed that, after modification, resin HX could form hydrogen-bond with berberine molecules. In the adsorption process, two C-O groups on berberine molecules became the electron acceptor of hydrogen-bond and the N-H group on resin molecules became the electron donor of hydrogen-bond. The existence of hydrogen-bond enhanced the adsorption force, and led to bigger amount of adsorption.

Study on Consist Property of High Wax and Super-Viscous Crude Oil

The consist property analysis of Daqing and Nile-Oman high wax crude oil and Liaohe super-viscous crude oil was carried on in the paper. The result showed the key factor of high wax crude oil pour point increasing lies in the wax crystal forming and growing and agglomerating at low temperature. The reason of high viscosity of Liaohe super-viscous crude oil has correlation to the high nitrogen polar group weight. The polar groups can form hydrogen bond to make adhesion stronger. At the same time, the crude oil flowing was restrained by increase the macromolecule connection agglomeration in crude oil. The analysis of resin wax ratio of crude oil showed the better viscosity decline effect was appeared only in the condition of resin wax ratio was appropriate.

Isostructuralism in a series of methylester/methylamide derivatives of (R,R)-O,O′-dibenzoyl tartaric acid; inclusion properties and guest-dependent homeotypism of the crystals of (R,R)-O,O′-dibenzoyltartaric acid diamide

The compounds studied are methyl ester, amide and methylamide derivatives of (R,R)-O,O′-dibenzoyl tartaric acid. The molecules adopt the planar T conformation of the four-carbon chain with the terminal C=O bonds situated antiperiplanar with respect to the nearest C*—O bond. All investigated molecules occupy a twofold symmetry site in the crystal, including the mono(N-methylamide) monomethylester which lacks the C 2 molecular symmetry. Connected with this is the static disorder in which the methylester and the N-methylamide groups replace each other and isostructuralism within the methylester/methylamide series. (R,R)-O,O′-Dibenzoyltartaric acid diamides [(R,R)-O,O′-dibenzoyl-2,3-dihydroxybutanediamides], both primary and secondary, form hydrogen-bond aggregation patterns typical for amides, despite the presence of other hydrogen-bond acceptors in the molecule. However, in primary amides such packing leads to the creation of homeotypic crystal structures in which structural voids are filled by cyclic solvent molecules (pyridine, 1,4-dioxane). The presence of polyamide ladders, consisting of `fused' hydrogen-bond rings, seems to be responsible for the low solubility and high melting point of these substances.

Development and Appraisal of Mucoadhesive Tablets of Hydralazine using Isolated Mucilage of Annona Squamosa Seeds

Bioadhesive materials are agents which adhere to the mucous membrane due to specific properties and release the drug at the site of action in a controlled fashion. Since the biodegradability of the synthetic polymer is at some instance hesitant. In this exploration, a bioadhesive polymer has been developed which was isolated from seeds of Annona squamosa (L.) Burm. fruit. The buccal bioadhesive tablet was prepared using Hydralazine and A. squamosa mucilage as bioadhesive polymer. The prepared tablets were evaluated against existing bioadhesive polymer like Carbopol 934 P and Polycarbophil. From the FTIR spectra it was found that mucilage contains functional group such as –OH, –NH confirmed that mucilage can probably form hydrogen bond with mucin which is required for the bioadhesion. Further FTIR Spectra reveled that there was no interaction between polymer and drug Hydralazine. Swelling index of A. squamosa mucilage was found to be 23 ± 1.4 (%) which was privileged than Polycarbophil but significantly lesser than Carbopol 934 P 22 ± 0.3 and 27 ± 1.6 (%) respectively. The outcome showed that force of adhesion of A. squamosa mucilage found to be 0.21 ± 0.08 N which was higher than Polycarbophil but lower than Carbopol 934 P having Force of adhesion 0.29 ± 0.02 N and 0.25 ± 0.06 respectively. The Ex-vivo Residence time and in-vitro drug release of optimize batch F2 found to be 6.8 h and 97 ± 0.4%. Drug permeation through buccal mucosa found to be 89 ± 0.16 % at the end of 10 hr. Overall study concluded that the mucilage of A. squamosa can be used as a pharmaceutical excipient in oral bioadhesive drug delivery systems