Different Numbers Of Hydroxyl Groups Research Articles

P.19.8 The effect of water-soluble fullerene with different number of hydroxyl groups in muscle regeneration process of experimental murine skeletal muscle

Muscular dystrophy is a hereditary disease, which cause severe muscle weakness and atrophy in clinically, and skeletal muscle degeneration and necrosis in pathology. In recent years, reducing oxidative stress is considered as one of the new treatment strategy in muscular dystrophy. Fullerene is a good candidate to detoxify and absorb free radical. We have already revealed that fullerene has a function to promote the regeneration of skeletal muscle. To evaluate the effectiveness of different type of water-soluble fullerenes, we chronologically evaluate the histology in mice tibial muscles during a cycle of regeneration induced by cardiotoxin injection. We used three types of water-soluble fullerene, 44 hydroxyl fullerene, fullerene with PVP, and fullerene with hydrophilic cyclodextrin. Tibial muscles of C57BL10 mice (4–5 weeks old) were injected with cardiotoxin with 3 different types of fullerene or without fullerene. The injected muscles were removed and stained H& E on 1, 3, 5, 7, 14, and 28 days after the injection. Western-blotting was performed to evaluate expression of muscle proteins, such as dystrophin, desmin, and nNOS. Average diameter of regenerate muscles 28 days after injection, fullerene group was bigger than those of cardiotoxin group. There was no difference of average diameter with 3 types of fullerene. Muscle protein expression in co-administered fullerene group, dystrophin, desmin, and nNOS was observed in the earlier stage by Western blot than those of cardiotoxin group. During the experiment, there is no significant and critical change was observed. We revealed that 44 hydroxyl fullerene, fullerene with PVP, and fullerene with hydrophilic cyclodextrin has the same function to promote the regeneration of skeletal muscle in this experiment. We believe that water-soluble fullerene reduce oxidative stress and can be applied in the treatment of muscular dystrophy.

Synthesis and characterization of ferrocene end-capped poly(ε-caprolactone)s by a combination of ring-opening polymerization and “click” chemistry techniques

Ferrocene (Fc) end-capped linear and star-shaped poly(ε-caprolactone)s (PCLs) with different numbers of arms were synthesized by a combination of ring-opening polymerization (ROP) and “click” chemistry techniques in a four-step reaction procedure. In the first step, the polymer backbones were prepared via ROP of the ε-caprolactone (ε-CL) monomer in bulk by employing the compounds with different numbers of hydroxyl groups as the multisite initiators and stannous octoate (Sn(Oct)2) as the coordination-insertion catalyst. The hydroxyl end-groups of the obtained PCLs were then converted into a bromides and azides consecutively. In the final step, the Fc moiety was attached to the termini of the PCLs using a Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction between the azide end-groups of the PCLs and the acetylene group of ethynylferrocene under ambient conditions. In all cases, the FT-IR and 1H NMR spectra indicated a successful and quantitative transformation of the desired end-functional groups. The electrochemical properties of the Fc end-capped PCLs were also investigated via cyclic voltammetry (CV).

Dendrimer-Encapsulated Pt Nanoparticles: An Artificial Enzyme for Hydrogen Production

Two series of dendrimer encapsulated Pt nanoparticles (DENPt) were created by using sixth generation poly(amidoamine) (PAMAM) dendrimers terminated with different numbers of hydroxyl groups (s-G6-OH and t-G6-OH) to mimic hydrogenases. Pt nanoparticles act as the active site to generate H2 by reducing H+, and dendrimers provide cavities to maintain the integrity of small Pt nanoparticles and prevent agglomeration. The artificial hydrogenases (t-G6-OH/Ptx and s-G6-OH/Ptx) were successfully applied to a light-induced hydrogen production system with Pt-tppa+, ethyl viologen, and TEOA as photosensitizer, electron relay, and sacrificial reagent, respectively, exhibiting excellent stability and efficient catalytic activity. No passivation effect is caused by the periphery hydroxyl groups of dendrimers. The optimal size of the Pt clusters consists of 200 Pt atoms, and the most adapted pH value is 9 to gain the highest catalytic efficiency in the applied hydrogen production system. This study provides a new strate...

Sorbents Based on Silica Containing Fullerenols for Use in Plasmapheresis

Sorbents based on silica containing fullerenols were obtained. Fullerenols having a different number of hydroxyl groups were incorporated in silica by two methods: solid-state reaction in a vacuum unit and a two-step synthesis using dimethyldicholorosilane and a tertiary amine. The sorbents obtained were proven to be highly selective for low-density lipoproteides (LDL) from blood plasma and can be used in plasmapheresis, in particular, for efferent therapy of atherosclerosis.

Solution-processed thin films based on sandwich-type mixed (phthalocyaninato)(porphyrinato) europium triple-deckers: Structures and comparative performances in ammonia sensing

The solution-processed thin films of a series of three sandwich-type mixed (phthalocyaninato)(porphyrinato) europium complexes with different numbers of hydroxyl groups at the meso-substituted phenyl groups of porphyrin ligand 1–3 were prepared by a quasi-Langmuir–Shäfer (QLS) method. Examination by spectroscopic methods revealed that J-type aggregates have been formed with the increasing degree of order of molecular stacking 1<2<3 films. The IR and XRD results reveal that, a dimeric supramolecular structure was formed depending mainly on the π–π interaction between the tetrapyrrole cores of neighboring triple-decker molecules, which, as the building blocks, self-assembled into the target nanostructures through intermolecular hydrogen bonds. Competition and cooperation between the intermolecular π–π interaction and hydrogen bonding for different compounds were revealed to result in thin-film microstructure with a different morphology from nano-grains for 1 and 2 and nano-sheets for 3. An increasing sensitivity to NH3 at varied concentrations in the range of 15–800ppm, follows the order 3<1<2, revealing the effect of film structure/morphology on sensing performance. In particular, excellent sensitivity, nearly complete reversibility and reproducibility to NH3 even at room temperature are obtained for the ultra-thin solution processed films from 2.

Low Molecular Weight Poly(Lactide-&amp;lt;i&amp;gt;co&amp;lt;/i&amp;gt;-Caprolactone) for Tissue Adhesion and Tetracycline Hydrochloride Controlled Release in Wound Management

The use of biopolymers as bioadhesives for human tissue is becoming a preferred alternative to suturing due to their superior adhesive, biocompatible, and biodegradable properties. In this work, low molecular weight poly(L-lactide-co-ε-caprolactone) (P(LA-co-CL) was synthesized to achieve the glass transition temperature (Tg) of the copolymer at ambient temperature so that during application on the skin, the copolymer when combined with chitosan (CHI) into the CHI/P(LA-co-CL) film could provide the strong support at the injury site. Using alcohols with different numbers of hydroxyl groups as the co-initiator in polymerization provided the distinctive characteristics of copolymers. Among all copolymers synthesized, P(LA-co-CL) copolymer using pentaerythritol as the co-initiator when combined with CHI at the ratio of copolymer/CHI at 70/30 yielded the good film properties in tissue adhesion and tetracycline hydrochloride release.

Structure–affinity relationship of flavones on binding to serum albumins: Effect of hydroxyl groups on ring A

Four flavones (flavone, 7-hydroxyflavone, chrysin, and baicalein) sharing the same B- and C-ring structure but a different numbers of hydroxyl groups on the A-ring were studied for their affinities for BSA and HSA. The hydroxylation on ring A of flavones increased the binding constants (K(a)) and the number of binding sites (n) between flavones and serum albumins. The affinities of 7-hydroxyflavone for BSA and HSA were about 800 times and 40 times higher than that of flavone, respectively. It appears that the optimal number of hydroxyl groups introduced to the ring A of flavones is one. As more hydroxyl groups were introduced to positions at C-5, C-6, and/or C-7 of flavones, the affinities for serum albumins decrease. The critical energy transfer distances (R(0)) between the hydroxylated flavones (1-3 OH on the ring A) and serum albumins decreased with the increasing affinities for serum albumins.

Synthesis and characterization of well-defined poly( tert-butyl acrylate) star polymers

Star polymers with different numbers and lengths of poly( tert-butyl acrylate) (PTBA) arms were obtained via atom transfer radical polymerization. Aliphatic alcohols with different number of hydroxyl groups varying from 3 to 6 and calix[4]arenes based on pyrogallol with 12 and 16 phenol groups were transformed to bromoester derivatives to prepare multifunctional ATRP initiators used as the cores of the stars. The star polymers were characterized by GPC with refractive index, multiangle laser light scattering and viscosimetric detectors. The molar masses of the stars reached 70,000 g/mol and the molar mass dispersities did not exceed 1.2. To elucidate the compact structure of the stars, their true molar masses were determined by GPC with triple detection (RI–MALLS–Visco) and compared with the apparent molar masses obtained from the calibration with linear poly( tert-butyl acrylate) standards. The intrinsic viscosities of the PTBA stars of the same molar mass decreased with the number of star arms but were always lower than the intrinsic viscosities of the analogue linear PTBA polymers. The values of the branching ratio g′ decreased with increasing number of arms indicating more compact structure of stars. The branching ratio g′ was correlated to the empirical predictions.

Why does acetylation protect wood from microbiological attack?

Three main mechanisms have been postulated for explaining why acetylation provides protection from wood against fungal decay, which can be divided into biochemical (substrate recognition) and physical (cell-wall nanopore blocking or cell-wall moisture content reduction) hypotheses. One way of examining the possible mechanism is to modify wood with anhydrides of different molecular weight so that for a specific weight percentage gain (WPG) different numbers of hydroxyl groups are substituted. The decay behaviour of wood modified in this way can be examined and the relationship between decay mass loss and WPG or OH substitution used to determine the relative influence of cell-wall bulking and substrate recognition. This has been done for a range of wood species and the results are reported.

General Quantum-Mechanical Study on the Hydrolysis Equilibria for a Tetravalent Aquaion: The Extreme Case of the Po(IV) in Water

A systematic study of the different hydrolyzed species derived from the hydrated Po(IV) in water, [Po(H(2)O)(n)(OH)(m)]((4-m)) for 1 m 4, and 4 m + n 9, has been carried out by means of quantum mechanical computations. The effects of outer solvation shells have been included using a polarizable continuum dielectric model. For a fixed number of hydroxyl groups, the preferred hydration number for the Po(IV) can be determined in terms of Gibbs energy. It is shown that the hydration number (n) systematically decreases with the increase in the number of hydroxyl groups (m) in such a way the total coordination number (n + m) becomes smaller, being 9 in the aquocomplex and 4 in the neutral hydroxo-complex. Free energies for the hydrolysis processes involving Po(IV) complexes and a different number of hydroxyl groups have been computed, revealing the strong tendency toward hydrolysis exhibited by these complexes. The predominant species of Po(IV) in aqueous solutions are ruled by a dynamical equilibrium involving aggregates containing in the first coordination shell OH(-) groups and water molecules. Although there is not experimental information to check the theoretical predictions, theoretical computations in solution seem to suggest that the most likely clusters are [Po(H(2)O)(5)(OH)(2)](2+) and [Po(H(2)O)(4)(OH)(2)](2+). The geometry of the different clusters is ruled by the trend of hydroxyl groups to be mutually orthogonal and to promote a strong perturbation of the water molecule in trans-position by lengthening the Po-H(2)O distances and tilting the corresponding bond angle. A general thermodynamic cycle is defined to compute the Gibbs free energy associated to the formation of the different hydrolyzed forms in solution. From it, the estimates of pK(a) values associated to the different protolytic equilibria are provided and discussed. Comparison of the relative values of pK(a) along a hydrolysis series with the experimental values for other tetravalent cations supports its consistency.

Morphology Controlled Self-Assembled Nanostructures of Sandwich Mixed (Phthalocyaninato)(Porphyrinato) Europium Triple-Deckers. Effect of Hydrogen Bonding on Tuning the Intermolecular Interaction

A series of five novel sandwich-type mixed (phthalocyaninato)(porphyrinato) europium triple-decker complexes with different numbers of hydroxyl groups at the meso-substituted phenyl groups of porphyrin ligand 1-5 have been designed, synthesized, and characterized. Their self-assembly properties, in particular the effects of the number and positions of hydroxyl groups on the morphology of self-assembled nanostructures of these triple-decker complexes, have been comparatively and systematically studied. Competition and cooperation between the intermolecular pi-pi interaction and hydrogen bonding in the direction perpendicular to the pi-pi interaction direction for different compounds were revealed to result in nanostructures with a different morphology from nanoleafs for 1, nanoribbons for 2, nanosheets for 3, and curved nanosheets for 4 and to spherical shapes for 5. The IR and X-ray diffraction (XRD) results reveal that, in the nanostructures of triple-decker 2 as well as 3-5, a dimeric supramolecular structure was formed through an intermolecular hydrogen bond between two triple-decker molecules, which as the building block self-assembles into the target nanostructures. Electronic absorption spectroscopic results on the self-assembled nanostructures reveal the H-aggregate nature in the nanoleafs and nanoribbons formed from triple-deckers 1 and 2 due to the dominant pi-pi intermolecular interaction between triple-decker molecules, but the J-aggregate nature in the curved nanosheets and spherical shapes of 4 and 5 depending on the dominant hydrogen bonding interaction in cooperation with pi-pi interaction among the triple-decker molecules. Electronic absorption and XRD investigation clearly reveal the decrease in the pi-pi interaction and increase in the hydrogen bonding interaction among triple-decker molecules in the nanostructures along with the increase of hydroxyl number in the order of 1-5. The present result appears to represent the first effort toward realization of controlling and tuning the morphology of self-assembled nanostructures of sandwich tetrapyrrole rare earth complexes through molecular design and synthesis.

Guest-induced inversion of an asymmetric host layer in inclusion crystals of cholic acid

Cholic acid, a typical asymmetric host, forms inclusion crystals with six 1,2,3-trisubstituted benzenes and five 1,2,4-trisubstituted benzenes as guests. All the eleven crystals have a bilayer structure composed of hydrophilic and lipophilic layers. The guest molecules are included in one-dimensional (1-D) cavities within the lipophilic layers, where the host molecules array in an antiparallel mode. On the other hand, in the absence of host–guest hydrogen bonds, the host arrangements in the hydrophilic layers change depending on the guest shape; 1,2,3- and 1,2,4-trisubstituted benzenes give the parallel and antiparallel arrangements that are categorized into shv and shv# patterns, respectively. The former crystals have a size-fit relationship between the guest molecule and the host cavity lesser than usual inclusion crystals involving the latter crystals. Therefore, the shape-fit relationship plays an important role in the formation of the host arrangements with the shv pattern. Moreover, the crystal structures of cholic acid with 1,2,3-trisubstituted benzenes are similar to those of deoxycholic acid with the identical guests. This is a rare example that hosts with a different number of hydroxyl groups in their molecular structure form an isomorphous crystal structure.

Application of Hansch's Model to Guaianolide Ester Derivatives: A Quantitative Structure−Activity Relationship Study

A quantitative structure-activity study to evaluate the effect of lipophilia/aqueous solubility on etiolated wheat coleoptiles elongation has been carried out with 34 guaianolides having different numbers of hydroxyl groups and ester side chains of variable length and structure: linear, branched, aromatic, and unsaturated. Compounds have been tested in a range of concentrations between 10 and 1000 microM. Data show a strong influence of lipophilia, expressed as logP values. Specially, data from alkylic side chain ester derivatives adjust to the mathematical model based on Hansch's transport theory; hence, a quantitative structure-activity relationships (QSAR) correlation with a high degree of reliance is provided. Moreover, all active compounds fit the Lipinski's rule of five. Also, the presence of additional hydroxyl groups and their derivatives in the basic skeleton does not affect the mode of action but greatly influences the activity, as they modify the transport through membranes and aqueous phases. Finally, a second hydroxyl group enhances differences of activity between alkylic side chain derivatives by increasing differences in van der Waals interactions.

TLC of ecdysteroids with four mobile phases and three stationary phases

Eleven mobile phases and three stationary phases have been investigated for TLC separation of a large number of ecdysteroids. Optimization of the chromatography was based on trial and error. Use of four mobile phases on three stationary phases enabled separation of all the ecdysteroids from each other in at least one system. The TLC behavior of ecdysteroids containing different numbers of hydroxyl groups, side-chain variations, and extra double bonds, and of positional isomers and stereoisomers, is reported and interpreted. Our method is suggested for screening plant extracts for ecdysteroids.

Synthesis of polylactides in the presence of co-initiators with different numbers of hydroxyl groups

Linear and star-shaped polylactides were prepared by using alcohols with different numbers of hydroxyl groups as co-initiators. 1H-NMR analysis of low molecular weight polymers showed that the number of hydroxyl groups initiating polymerisation was near theoretical for 1,4-butanediol (2 OH groups) and pentaerythritol (4 OH groups). The numbers for polyglycerines were somewhat lower than theoretical (8 or 12 OH groups), but they clearly suggested the star-shaped structure, with more arms than in polymers initiated with pentaerythritol. The preparation of high molecular weight polymers showed that the polymerisation rate increases with the number of hydroxyl groups in the co-initiator. Along with the faster polymerisation, higher molecular weight polymers were obtained. High hydroxyl group content in the polymer did not cause a drop in the conversion level or enhanced backbiting during extended polymerisation. Furthermore, the co-initiator did not affect the thermal properties of the polymers except that slightly lower melting temperatures were measured for star-shaped than linear polylactides.

Group additive contributions to the alcohol-induced α-helix formation of melittin: implication for the mechanism of the alcohol effects on proteins

Detailed analysis of the effects of alcohols on proteins and peptides is important because of its wide range of applications in many fields. Whereas melittin, a major component of honeybee venom, is unfolded in an aqueous environment, the addition of alcohols induces an α-helical structure. We used circular dichroism (CD) to compare the effects of various alcohols on melittin. Whereas the α-helical state was basically independent of alcohol species, the effectiveness of alcohols varied significantly. Among alkanols, the effectiveness was proportional to the bulkiness of hydrocarbon groups, indicating that the hydrocarbon group contributes positively to the alcohol effects. Comparison of alcohols with the same hydrocarbon group but a different number of hydroxyl groups showed that the hydroxyl groups contribute negatively to the alcohol effects. Comparison of several halogenols indicated that halogen increases the effectiveness in the order of F < C l< Br. These results suggested that the effects of alcohol can be interpreted by the additive contributions of each of the constituent groups of the alcohol, which are proportional to the solvent-accessible surface area. However, for markedly effective alcohols such as 1,1,1,3,3,3-hexafluoro-2-propanol, the aggregation of alcohols was suggested to further enhance these effects. We have constructed equations for estimating the effectiveness of alcohols in inducing α-helical structure, which should also be useful for predicting the other effects of alcohols on proteins.

Use of hydrophilic diamines for bridging of two opioid peptide pharmacophores

The bivalent ligand approach, which assumes that two pharmacophores are connected by a spacer, was used to design receptor type-selective ligands for opioid receptors. The first two opioid peptide bivalent ligands with different spacer lengths containing different numbers of hydroxyl groups, (Tyr-D-Ala-Gly-Phe-NH-CH2-CHOH-)2 (Tyr-D-Ala-Gly-Phe-NH-CH2-CHOH-CHOH-)2, were synthesized and their binding to mu, delta, and kappa opioid receptors was characterized. Both analogues were found to possess high opioid in vitro activities. The length of the hydrophilic spacer does not affect the affinity for delta receptors, whereas shorter spacer length increases affinity for mu and even more so for kappa receptors. Thus receptor type-selective peptides for opioid receptors can be designed using the bivalent approach.

Sarcophytols A and B inhibit tumor promotion by teleocidin in two-stage carcinogenesis in mouse skin

Sarcophytols A and B, isolated from a soft coral, Sarcophyton glaucum, are cembrane-type diterpenes with different numbers of hydroxyl groups. Sarcophytols A and B inhibited tumor promotion by teleocidin in two-stage carcinogenesis experiments on mouse skin. The inhibitory effect of sarcophytol A was demonstrated with two different initiating doses of 7,12-dimethylbenz[a]anthracene (DMBA): 50 micrograms (experiment 1) and 100 micrograms (experiment 2). In experiment 1, three groups of mice were treated with DMBA, and then twice a week with doses (1.6 micrograms, 16 micrograms, and 82 micrograms) of sarcophytol A followed by 2.5 micrograms teleocidin. In week 25, the incidences of tumors in these groups were only 7.1%, 20.0%, and 13.3%, respectively, whereas that in the control group treated with DMBA plus teleocidin was 53.3%. Moreover, at this time, the average numbers of tumors per mouse in these groups were 0.1, 0.3, and 0.3, respectively, while that in the control group was 2.1. In experiment 2 an amount of sarcophytol A (1.6 micrograms) or B (1.7 micrograms) equimolar to 2.5 micrograms teleocidin was applied twice a week, as in experiment 1, and results showed that sarcophytol B also inhibited tumor promotion by teleocidin. Both sarcophytols A and B caused delay in onset of tumor formation, and reduced the percentage of tumor-bearing mice and the average number of tumors per mouse. The effective concentrations of sarcophytols A and B were in the microgram range with an equimolar amount of teleocidin.

Aggregate Morphology of Peptide Lipids Having Hydroxyl Groups: Molecular Basis for Formation of Inverted Hexagonal, Inverted Cubic, Bilayer, and Micellar Phases

Abstract Three types of peptide lipids having different numbers of hydroxyl groups in their head moieties, (HO)C5Ala2Cn, QC5Ala2Cn and Q2LysC5Ala2Cn (n=14, 16), were prepared, and their morphological behavior was investigated by various physical techniques: negative staining and freeze-fracture electron microscopy, low-angle X-ray diffraction, selected area electron diffraction, fluorescence polarization spectroscopy, and differential scanning calorimetry. QC5Ala2Cn, having four hydroxyl groups in the head moiety, underwent aggregation in the aqueous dispersion state to afford the nonbilayer phase, which was constituted with highly developed globular domains with face-centered cubic (CII) lattice, above the phase transition temperature (Tm). This CII phase was transformed into the bilayer one below Tm. On the other hand, Q2LysC5Ala2Cn, having eight hydroxyl groups in the head moiety, formed bilayer aggregates in a whole temperature range, above and below Tm. Deprotonation of the hydroxyl groups of QC5Ala2Cn and Q2LysC5Ala2Cn resulted in morphological changes to afford the bilayer and micellar phases, respectively. Two-component lipid systems composed of (HO)C5Ala2C14 and Q2LysC5Ala2C14 at appropriate molar ratios afforded the inverted hexagonal (HII) phase in the aqueous dispersion state; the first example of the HII phase formed with artificial double-chain amphiphiles. The aggregate morphology was discussed on the basis of the critical packing mode of lipid molecules.