Theoretical Investigations of State Specific Hydrogen Atom Transfer in 8-Formyl-7-hydroxy-4-methylcoumarin

Excited state intramolecular hydrogen transfer (ESIHT) reaction of 8-formyl-7-hydroxy-4-methyl coumarin (FC) in its pure and hydrated state FC-(H2O)4 (FCH) has been studied by implementing state specific time dependent density functional theory (SS-TDDFT) along with the effective fragment potential (EFP1) method for solvation with discrete water molecules. The intramolecular hydrogen bond formed between hydroxyl hydrogen (H18) and formyl oxygen (O15) and intermolecular hydrogen bonds formed due to microsolvation were explored. The studies of electrostatic potential, natural charge analysis, difference electron density map and UV-Vis spectra of both FC and FCH molecules establish the intramolecular charge transfer (ICT) states of the molecules. The vertical excitation from S0 to S1 state causes the transfer of hydroxyl hydrogen to formyl oxygen and from S1 to S3 causes the transfer of the hydrogen atom back to hydroxyl oxygen. Potential energy surface scans along intramolecular hydrogen bonding at the ground and excited states confirm the state specific ESIHT reaction in both FC and FCH molecules.

Comparative Antibacterial Analysis of the Anthraquinone Compounds Based on the AIM Theory and Molecular Docking Analysis

Hydroxyanthraquinones and anthraquinone glucoside derivatives are always considered as the active antibacterial components. In the present text, a comprehensive comparison and analysis of these compounds were performed for their structure characteristics and antibacterial effect by applying quantum chemical calculations, atoms in molecules theory and molecular docking procedure. The molecular geometric configuration, electrostatic potential, the frontier orbital energies and topological properties were analyzed. Once glucose ring is introduced into the hydroxyanthraquinone rings, almost all of the positive molecular potentials are distributed among the hydroxyl hydrogen atoms of the glucose rings. The anthraquinone glucoside compounds have generally higher intermolecular binding energies than the corresponding aglycones due to the strong interaction between the glucose rings and the surrounding amino acids. Once glucoside ring is introduced into the emodin, low electron density ρ(r) and positive Laplacian value of the O-H bond are the evidences of the highly polarized and covalently decreased bonding interactions. The type of carboxyl, hydroxyl, hydroxylmethyl groups on phenyl ring and the substituent glucose rings are important to the interactions with the topoisomerase type II enzyme DNA gyrase B.

Free Radical Scavenging potential of different extracts of Tabebuia roseo-alba (Ridl) Sand leaves

The present study was carried out to elucidate the in vitro free radical scavenging potential of various extracts of Tabebuia roseo-alba leaves. Assays for radical scavenging, such as DPPH, ABTS+, hydroxyl, hydrogen peroxide, superoxide, nitric oxide assay and reducing power activity were performed using standard protocols and the results were compared with standard ascorbic acid. Among the various extracts used the ethanolic extract of T. roseo-alba exhibited efficient scavenging potential with lowest EC50 value proving its antioxidant potential. Leaves of T. roseo-alba have strong free radical scavenging properties and thus can be used as a potential antioxidant to resolve diseases that are associated with oxidative stress including diabetes and other age related disorders.

Antioxidant activity and Hepatoprotective potential of Ethanolic leaf extract of Artabotrys hexapetalus against various Hepatotoxins induced Hepatotoxicity in Albino wister Rats

The objective of this research was to see whether the ethanolic extract of Artabotrys hexapetalus leaves had antioxidant and hepatoprotective properties against paracetamol (PCT), ethanol (ETN), and isoniazid and rifampicin (IR)-induced hepatotoxicity in Albino Wister rats. The materials were dried in the shade, pulverised, and extracted using ethanol. Phytochemical experiments were carried out as a first step. The ethanol extract's hepatoprotective activity was evaluated in Albino Wister rats. PCT (3 g/kg), ETN (5 g/kg), and IR (100 mg/kg) reduced the levels of SGOT, SGPT, ALP, and bilirubin, which are all biochemical indicators of liver injury. Both hepatotoxin-treated and untreated group of animals determined for their antioxidant levels. Aspartate aminotransferase (SGOT), alanine transaminase (SGPT), alkaline phosphatase (ALP), bilirubin, an antioxidant function of DPPH (1,1-diphenyl 2-picryl hydroxyl), hydrogen peroxide (H2O2), lipid peroxidation methods, hydroxyl radicals, and nitric oxide were among the biochemical and histopathological tests performed. The altered levels of biochemical markers were restored to near-normal levels in a dose-dependent fashion after treatment with A. hexapetalus ethanolic leaf extract (100 mg/kg, 200 mg/kg, and 400 mg/kg body weight). The findings of the current research indicated that the ethanol leaf extract of A. hexapetalus had potent antioxidant and hepatoprotective properties.

Non-covalent interactions involving remote substituents influence the topologies of supramolecular chains featuring hydroxyl-O–H⋯O(hydroxyl) hydrogen bonding in crystals of (HOCH2CH2)2NC(S)N(H)(C6H4Y-4) for Y = H, Me, Cl and NO2

Secondary non-covalent interactions prove crucial in determining the topology of supramolecular chains sustained by conventional O–H⋯O hydrogen bonding.

Comparison of Functional Properties of the Bael Fruit at Various Levels of Maturity

Aegle marmelos fruit is packed with immense medicinal properties. The main objective of the studywas to assess and compare the phytochemical potency, antioxidant capacity and anti-inflammatory activity of unripe, ripe and overripe fruits. The fruit pulp was dried and extract (ripe fruit) was prepared in various solvents. Phytochemical assessment was done and the solvent which exhibited maximum potency was chosen as unripe and ripe fruit solvents. Phytochemical assessment, estimation of phenols (FolinCiocalteau method), antioxidant capacity (Molybdate method), anti-inflammatory activity (membrane stabilization property method) and Free radical scavenging capacity for hydroxyl, hydrogen peroxide and DPPH free radicals were carried out. The phytochemical screening of the ripe fruit showed maximum intensity in hydroethanolic extract. On comparison, ripe fruit extract possessed a greater phytochemical potency, antioxidant capacity and inhibition against hydroxyl, hydrogen peroxide, DPPH radicals. The total phenolic content of the over ripe fruit was high. The anti-inflammatory activity of unripe fruit was slightly higher than ripe fruit. This signifies that phytochemical potency and functional properties of the fruit differs with maturity stages.

Amphipathic Substrates Based on Crosslinker-Free Poly(ε-Caprolactone):Poly(2-Hydroxyethyl Methacrylate) Semi-Interpenetrated Networks Promote Serum Protein Adsorption

A simple procedure has been developed to synthesize uncrosslinked soluble poly(hydroxyethyl methacrylate) (PHEMA) gels, ready for use in a subsequent fabrication stage. The presence of 75 wt % methanol (MetOH) or dimethylformamide (DMF) impedes lateral hydroxyl–hydroxyl hydrogen bonds between PHEMA macromers to form during their solution polymerization at 60 °C, up to 24 h. These gels remain soluble when properly stored in closed containers under cold conditions and, when needed, yield by solvent evaporation spontaneous physically-crosslinked PHEMA adapted to the mould used. Moreover, this two-step procedure allows obtaining multicomponent systems where a stable and water-affine PHEMA network would be of interest. In particular, amphiphilic polycaprolactone (PCL):PHEMA semi-interpenetrated (sIPN) substrates have been developed, from quaternary metastable solutions in chloroform (CHCl3):MetOH 3:1 wt. and PCL ranging from 50 to 90 wt % in the polymer fraction (thus determining the composition of the solution). The coexistence of these countered molecules, uniformly distributed at the nanoscale, has proven to enhance the number and interactions of serum protein adsorbed from the acellular medium as compared to the homopolymers, the sIPN containing 80 wt % PCL showing an outstanding development. In accordance to the quaternary diagram presented, this protocol can be adapted for the development of polymer substrates, coatings or scaffolds for biomedical applications, not relying upon phase separation, such as the electrospun mats here proposed herein (12 wt % polymer solutions were used for this purpose, with PCL ranging from 50% to 100% in the polymer fraction).

Effects of Hydroxyl Group on the Interaction of Carboxylated Flavonoid Derivatives with S. Cerevisiae α-Glucosidase

Introduction: Carboxyalkyl flavonoids derivatives are considered as effective inhibitors in reducing post-prandial hyperglycaemia. Methods: Combined with Density Functional Theory (DFT) and the theory of Atoms in Molecules (AIM), molecular docking and charge density analysis are carried out to understand the molecular flexibility, charge density distribution and the electrostatic properties of these carboxyalkyl derivatives. Results: Results show that the electron density of the chemical bond C14-O17 on B ring of molecule II increases while O17-H18 decreases at the active site, suggesting the existence of weak noncovalent interactions, most prominent of which are H-bonding and electrostatic interaction. When hydroxyl groups are introduced, the highest positive electrostatic potentials are distributed near the B ring hydroxyl hydrogen atom and the carboxyl hydrogen atom on the A ring. It was reported that quercetin has a considerably inhibitory activity to S. cerevisiae α-glucosidase, from the binding affinities, it is suggested that the position and number of hydroxyl groups on the B and C rings are also pivotal to the hypoglycemic activity when the long carboxyalkyl group is introduced into the A ring. Conclusion: It is concluded that the presence of three well-defined zones in the structure, both hydrophobicity alkyl, hydrophilicity carboxyl and hydroxyl groups are necessary.

Intertwined chemistry of hydroxyl hydrogen-bond donors, epoxides and isocyanates in the organocatalytic synthesis of oxazolidinones versus isocyanurates: rational catalytic investigation and mechanistic understanding

The efficiency and chemoselectivity of the cycloaddition of isocyanates to epoxides to afford oxazolidinones were investigated using hydroxyl hydrogen-bond donors as organocatalysts.

In Vitro Antioxidant Properties of Dichloromethanolic Leaf Extract of Gnidia glauca (Fresen) as a Promising Antiobesity Drug

The acquisition of ethnobotanical information from traditional practitioners remains an empirical aspect of understanding the ethnopharmacology research. However, integration of information on chemical composition of plant extracts and their pharmacological activities forms a key resource for synthesis of new and effective therapeutics. In traditional African medicine, Gnidia glauca has folkloric remedies against obesity and its associated oxidative stress-mediated complications. However, the upsurge in its use has not been accompanied with scientific validations to support these claims. The present study aimed to determine the antioxidant potential of G glauca as a promising antiobesity agent. The antioxidant effects of the extract were assessed against 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, hydrogen peroxide, nitric oxide, and superoxide radicals as well as lipid peroxidation, iron-chelating effect, and ferric-reducing power. Phytochemical analysis was conducted using gas chromatography linked to mass spectrophotometry. The results revealed that G glauca exhibited scavenging activities against all radicals formed. Besides, the extract showed iron chelation and ferric reducing abilities. The extract indicated a lower half maximal inhibitory concentration value than the standards used. For instance, the extract inhibited 50% of the formation of 2,2-diphenyl-1-picrylhydrazine at the concentration of 1.33 ± 0.03 mg/mL relative to 1.39 ± 0.06 mg/mL of the standard, vitamin C at 1% confidence limit. Similarly, the extract scavenged 50% of hydroxyl radical at 204.34 ± 10.64 μg/mL relative to 210.05 ± 8.80 μg/mL of gallic acid. The extract also contained various phytochemicals that have been associated with antiobesity effects. The synergistic effects of these phytocompounds increase their bioavailability and action on multiple molecular targets thereby correcting obesity-induced oxidative stress.