Synergism between basic Asp49 and Lys49 phospholipase A2 myotoxins of viperid snake venom in vitro and in vivo

Two subtypes of phospholipases A₂ (PLA₂s) with the ability to induce myonecrosis, ‘Asp49’ and ‘Lys49’ myotoxins, often coexist in viperid snake venoms. Since the latter lack catalytic activity, two different mechanisms are involved in their myotoxicity. A synergism between Asp49 and Lys49 myotoxins from Bothrops asper was previously observed in vitro, enhancing Ca²⁺ entry and cell death when acting together upon C2C12 myotubes. These observations are extended for the first time in vivo, by demonstrating a clear enhancement of myonecrosis by the combined action of these two toxins in mice. In addition, novel aspects of their synergism were revealed using myotubes. Proportions of Asp49 myotoxin as low as 0.1% of the Lys49 myotoxin are sufficient to enhance cytotoxicity of the latter, but not the opposite. Sublytic amounts of Asp49 myotoxin also enhanced cytotoxicity of a synthetic peptide encompassing the toxic region of Lys49 myotoxin. Asp49 myotoxin rendered myotubes more susceptible to osmotic lysis, whereas Lys49 myotoxin did not. In contrast to myotoxic Asp49 PLA₂, an acidic non-toxic PLA₂ from the same venom did not markedly synergize with Lys49 myotoxin, revealing a functional difference between basic and acidic PLA₂ enzymes. It is suggested that Asp49 myotoxins synergize with Lys49 myotoxins by virtue of their PLA₂ activity. In addition to the membrane-destabilizing effect of this activity, Asp49 myotoxins may generate anionic patches of hydrolytic reaction products, facilitating electrostatic interactions with Lys49 myotoxins. These data provide new evidence for the evolutionary adaptive value of the two subtypes of PLA₂ myotoxins acting synergistically in viperid venoms.

[Study on chemical constituents from active fraction of Cynanchum versicolor]

OBJECTIVE

To investigate the chemical constituents of active fraction of Cynanchum versicolor.

METHODS

The ethanol extract of Cynanchum versicolor was purified by macroporous resin, silica gel column and Sephadex LH-20 column chromatography, and structures of the isolated compounds were identified by spectroscopic analysis and comparison with those of literatures.

RESULTS

Six compounds were isolated and identified as glaucogenin C (I), 24-methyl-5α-cholesta-7,22-diene-3β,5,6β-triol (II), syringic acid (III), 3,4-dihydroxyacetophenone (IV), 4-hydroxyacetophenone (V), and 4-hyroxy-3-methoxyacetophenone (VI).

CONCLUSION

Compounds I, II and IV are isolated from this plant for the first time.

Synthesis, vibrational, NMR, quantum chemical and structure-activity relation studies of 2-hydroxy-4-methoxyacetophenone

The stable geometry of 2-hydroxy-4-methoxyacetophenone is optimised by DFT/B3LYP method with 6-311++G(∗∗) and cc-pVTZ basis sets. The structural parameters, thermodynamic properties and vibrational frequencies of the optimised geometry have been determined. The effects of substituents (hydroxyl, methoxy and acetyl groups) on the benzene ring vibrational frequencies are analysed. The vibrational frequencies of the fundamental modes of 2-hydroxy-4-methoxyacetophenone have been precisely assigned and analysed and the theoretical results are compared with the experimental vibrations. 1H and 13C NMR isotropic chemical shifts are calculated and assignments made are compared with the experimental values. The energies of important MO's, the total electron density and electrostatic potential of the compound are determined. Various reactivity and selectivity descriptors such as chemical hardness, chemical potential, softness, electrophilicity, nucleophilicity and the appropriate local quantities are calculated.

Contribution of thermal energy to initial ion production in matrix-assisted laser desorption/ionization observed with 2,4,6-trihydroxyacetophenone

RATIONALE

Although several reaction models have been proposed in the literature to explain matrix-assisted laser desorption/ionization (MALDI), further study is still necessary to explore the important ionization pathways that occur under the high-temperature environment of MALDI. 2,4,6-Trihydroxyacetophenone (THAP) is an ideal compound for evaluating the contribution of thermal energy to an initial reaction with minimum side reactions.

METHODS

Desorbed neutral THAP and ions were measured using a crossed-molecular beam machine and commercial MALDI-TOF instrument, respectively. A quantitative model incorporating an Arrhenius-type desorption rate derived from transition state theory was proposed. Reaction enthalpy was calculated using GAUSSIAN 03 software with dielectric effect. Additional evidence of thermal-induced proton disproportionation was given by the indirect ionization of THAP embedded in excess fullerene molecules excited by a 450 nm laser.

RESULTS

The quantitative model predicted that proton disproportionation of THAP would be achieved by thermal energy converted from a commonly used single UV laser photon. The dielectric effect reduced the reaction Gibbs free energy considerably even when the dielectric constant was reduced under high-temperature MALDI conditions. With minimum fitting parameters, observations of pure THAP and THAP mixed with fullerene both agreed with predictions.

CONCLUSIONS

Proton disproportionation of solid THAP was energetically favorable with a single UV laser photon. The quantitative model revealed an important initial ionization pathway induced by the abrupt heating of matrix crystals. In the matrix crystals, the dielectric effect reduced reaction Gibbs free energy under typical MALDI conditions. The result suggested that thermal energy plays an important role in the initial ionization reaction of THAP.

Synthesis and docking studies of 2,4,6-trihydroxy-3-geranylacetophenone analogs as potential lipoxygenase inhibitor

The natural product molecule 2,4,6-trihydroxy-3-geranyl-acetophenone (tHGA) isolated from the medicinal plant Melicope ptelefolia was shown to exhibit potent lipoxygenase (LOX) inhibitory activity. It is known that LOX plays an important role in inflammatory response as it catalyzes the oxidation of unsaturated fatty acids, such as linoleic acid to form hydroperoxides. The search for selective LOX inhibitors may provide new therapeutic approach for inflammatory diseases. Herein, we report the synthesis of tHGA analogs using simple Friedel-Craft acylation and alkylation reactions with the aim of obtaining a better insight into the structure-activity relationships of the compounds. All the synthesized analogs showed potent soybean 15-LOX inhibitory activity in a dose-dependent manner (IC₅₀ = 10.31–27.61 μM) where compound 3e was two-fold more active than tHGA. Molecular docking was then applied to reveal the important binding interactions of compound 3e in soybean 15-LOX binding site. The findings suggest that the presence of longer acyl bearing aliphatic chain (5Cs) and aromatic groups could significantly affect the enzymatic activity.

Discovery, synthesis and characterization of a highly muscarinic acetylcholine receptor (mAChR)-selective M5-orthosteric antagonist, VU0488130 (ML381): a novel molecular probe

Of the five G-protein-coupled muscarinic acetylcholine receptors (mAChRs; M1-M5), M5 is the least explored and understood due to a lack of mAChR subtype-selective ligands. We recently performed a high-throughput functional screen and identified a number of weak antagonist hits that are selective for the M5 receptor. Here, we report an iterative parallel synthesis and detailed molecular pharmacologic profiling effort that led to the discovery of the first highly selective, central nervous system (CNS)-penetrant M5-orthosteric antagonist, with sub-micromolar potency (hM5 IC50=450 nM, hM5 Ki=340 nM, M1-M4 IC50>30 μM), enantiospecific inhibition, and an acceptable drug metabolism and pharmacokinetics (DMPK) profile for in vitro and electrophysiology studies. This compound will be a powerful tool and molecular probe for the further investigation into the role of M5 in addiction and other diseases.

[Preparation of paeonol transdermal delivery systems based on proniosomes-based ointment and its pharmacokinetics characters]

The paeonol proniosomes ointment and ordinary ointment were administered to rats. Physiological saline served as perfused solution. The perfusion rate was 5 mL x L(-1) and the microdialysis samples were collected every 20 min intervals. The paeonol concentration in perfused solution was determined by HPLC. Investigation of the pharmacokinetics of paeonol proniosomes ointment and ordinary ointment by the skin-blood synchronous microdialysis coupled with HPLC is reported in this study. The results show that the recovery was (54.80 +/- 1.50)% in vitro and (54.58 +/- 4.61)% in vivo. The results showed that paeonol proniosomes ointment significantly raised the drug concentrations in skin more than the paeonol ordinary ointment. The paeono proniosomes ointment has less drugs into the blood as the ordinary ointments in blood, but its blood drug concentrations were steadier. The paeonol proniosomes ointment may be developed into a new preparation.

[Chemical constituents of n-BuOH extract from Phyllanthus matsumurae]

OBJECTIVE

To study the chemical constituents of n-BuOH extract from Phyllanthus matsumurae.

METHODS

Column chromatography was used for the isolation and purification. Spectroscopic methods including H-NMR, 13C-NMR and MS were used for the identification of structures.

RESULTS

Six compounds were isolated from the n-BuOH extract of 75% alcohol extract of the whole plant and identified as ellagic acid (1), phyllanthuspermin B (2), phyllanthuspermin C (3), xanthoxylin (4), hesperetin-7-O-[6-O-(alpha-L-rhamnopy ranosyl)] -beta-D-glucopyranoside (5) and 4-O-methylgallic acid (6).

CONCLUSION

Compounds 2 - 6 are obtained from this plant for the first time.

Ultrasound and microwave assisted synthesis of dihydroxyacetophenone derivatives with or without 1,2-diazine skeleton

A thorough study concerning O-alkylation and α-bromination of dihydroxyacetophenone (DA) and N-alkylation of 1,2-diazine, under ultrasound (US) and microwave (MW) irradiation as well as under conventional thermal heating (TH) is presented. Under US and MW irradiation the yields are higher, the amount of used solvent decreases substantially, the reaction time decreases considerable (from hours or days to minutes) and the consumed energy decreases, consequently the O-alkylation, α-bromination and N-alkylation methods could be considered environmentally friendly. A selective and efficient way to either bis-O-alkylation or mono-O-alkylation of DA has been found, the relative position of the two hydroxyl groups on the phenyl moiety being compulsory. A selective and efficient way for α-bromination in heterogeneous catalysis of DA derivatives under US irradiation is presented. The N-alkylation reaction of DA under US and MW irradiation proved to be the most convenient setup procedure for these types of reactions. Overall, the use of US proved to be more efficient than MW or TH.

Computational study of the vibrational spectroscopic studies, natural bond orbital, frontier molecular orbital and second-order non-linear optical properties of acetophenone thiosemicarbazone molecule

The vibrational frequencies of acetophenone thiosemicarbazone in the ground state have been calculated using density functional method (B3LYP) with 6-31G(d), 6-31G(d,p) and 6-311++G(d,p) basis sets. The analysis of natural bond orbital was also performed. The IR spectra were obtained and interpreted by means of potential energies distributions (PEDs) using MOLVIB program. In addition, the results show that there exist N-H…N and N-H…S hydrogen bonds in the title compound, which play a major role in stabilizing the molecule and are confirmed by the natural bond orbital analysis. The predicted NLO properties show that the title compound is a good candidate as second-order NLO material. In addition, the frontier molecular orbitals were analyzed and the crystal structure obtained by molecular mechanics belongs to the Pbca space group, with lattice parameters Z=8, a=16.0735 Å, b=7.1719 Å, c=7.8725 Å, ρ=0.808 g/cm(3).

Is energy pooling necessary in ultraviolet matrix-assisted laser desorption/ionization?

RATIONALE

Energy pooling has been suggested as the key process for generating the primary ions during ultraviolet matrix-assisted laser desorption/ionization (UV-MALDI). In previous studies, decreases in fluorescence quantum yields as laser fluence increased for 2-aminobenzoic acid, 2,5-dihydroxybenzoic acid (2,5-DHB), and 3-hydroxypicolinic acid were used as evidence of energy pooling. This work extends the research to other matrices and addresses whether energy pooling is a universal property in UV-MALDI.

METHODS

Energy pooling was investigated in a time-resolved fluorescence experiment by using a short laser pulse (355 nm, 20 ps pulse width) for excitation and a streak camera (1 ps time resolution) for fluorescence detection.

RESULTS

The excited-state lifetime of 2,5-DHB decreased with increases in laser fluence. This suggests that a reaction occurs between two excited molecules, and that energy pooling may be one of the possible reactions. However, the excited-state lifetime of 2,4,6-trihydroxyacetophenone (THAP) did not change with increases in laser fluence. The upper limit of the energy pooling rate constant for THAP is estimated to be approximately 100-500 times smaller than that of 2,5-DHB.

CONCLUSIONS

The small energy pooling rate constant for THAP indicates that the potential contribution of the energy pooling mechanism to the generation of THAP matrix primary ions should be reconsidered.

Raman spectroscopic and ab initio studies on the molecular interactions in the binary liquid mixtures of 4'-fluoroacetophenone

Raman spectral measurements were carried out for binary liquid mixtures 4'fluoroacetophenone (4F) in different volume concentration ranges at a regular intervals of 0.1 in different solvents. The asymmetric Raman peak observed at 1685 cm(-1) (carbonyl stretching mode) in pure 4F confirms the presence of self association in 4F. The optimization was performed for monomer and dimer structures of 4F as well as 4F dimer with solvents using Gaussian 03 W package. Vibrational wavenumber calculation was performed for monomer and dimer structures of 4F to explain the experimentally observed Raman spectra. The carbonyl stretching mode is the more polar group and its interaction with the solvent molecule plays a vital role in determining the physical and chemical properties of the solute. Hence the observed variation in the peak position and linewidth of carbonyl stretching mode was analysed as a result of intermolecular interactions between the solute and the solvent molecules. Also, interaction energies were calculated to support the results obtained from Raman spectra.

Reduced graphene oxide: firm support for catalytically active palladium nanoparticles and game changer in selective hydrogenation reactions

Simultaneous decomposition and reduction of a Pd(2+) complex in the presence of graphene oxide (GO) lead to the formation of Pd(0)-nanoparticles (Pd-NPs) with average sizes of 4 nm firmly anchored on reduced graphene oxide (RGO) sheets. The Pd-NP/RGO hybrids exhibited remarkable catalytic activity and selectivity in mild hydrogenation reactions where the acidic properties of RGO play an active role and may act as an important game-changer.

Synthesis and spectroscopic characterization of 3,4-difluoroacetophenone-thiosemicarbazone and its palladium(II) complex: evaluation of antimicrobial and antitumour activity

A new cis-palladium(II)diaqua(3,4-difluoroacetophenonethiosemicarbazone complex (Pd(II) complex) is synthesized using 3,4-difluoroacetophenonethiosemicarbazone(L). The L and its Pd(II) complex are characterized and confirmed by elemental analyses, electrochemical analyses, FT-IR, FT-Raman, UV-Vis, HRMS and LC-MS techniques. Ligand L is further characterized by (1)H, (13)C and (19)F NMR spectroscopy. The crystal structure of L is unambiguously characterized by single X-ray crystallography. The ligand (L) belongs to monoclinic system with P2(1)/C space group and the unit cell parameters are a(Å)=9.1144(7), b(Å)=13.7928(7), c(Å)=8.4174(5), α(°)=90, β(°)=100.715, γ(°)=90 and volume V(A(3))=1039.73(11). The Raman bands observed for the L and its Pd(II) complex are in good agreement with the FT-IR spectral data. The Pd(II) complex is found to be highly efficient in inhibiting the growth of human pathogens like Salmonella typhimurium and Klebsiella pneumonia with MIC value 10.0μg/mL whose inhibition zones are almost comparable with the standard antibiotic. The synthesized compounds have shown antiproliferative activity against the human breast cancer cell lines MDA-MB231 by intermitting the regular pathway of ribonucleotidereductase.

Metal-free transannulation reaction of indoles with nitrostyrenes: a simple practical synthesis of 3-substituted 2-quinolones

3-Substituted 2-quinolones are obtained via a novel, metal-free transannulation reaction of 2-substituted indoles with 2-nitroalkenes in polyphosphoric acid. The reaction can be used in conjunction with the Fisher indole synthesis offering a practical three-component heteroannulation methodology to produce 2-quinolones from arylhydrazines, 2-nitroalkenes and acetophenone.

Synthesis of imine and reduced imine compounds containing aromatic sulfonamide: use as catalyst for in situ generation of ruthenium catalysts in transfer hydrogenation of acetophenone derivatives

Three imine and three reduced imine ligands containing aromatic sulfonamide (2-7) were isolated by a simple method and characterized by FT-IR, NMR, and elemental analysis. Meanwhile, the interaction of 2-7 ligands with [(p-cymene)RuCl2]2 was analyzed in situ by UV-vis spectrophotometer. The in situ generated catalytic system derived from N-(2-(benzylideneamino)phenyl)-2,4,6-trimethyl-benzenesulfonamides and N-(2-(benzylamino)phenyl)-2,4,6-trimethyl-benzenesulfonamides with [(p-cymene)RuCl2]2 was used as a catalyst in the transfer hydrogenation (TH) of p-substituted acetophenone derivatives. The catalytic systems displayed high activities, which increased in the order 7<4<5<6<1<2<3. The best activity for the TH of 4-chloroacetophenone was provided with the [(p-cymene)RuCl2]2/ligand (3) catalytic system (turnover frequency values: 720 h(-1) for 10 min on S/C: 500/1).

Photochemical transformation of ibuprofen into harmful 4-isobutylacetophenone: pathways, kinetics, and significance for surface waters

The harmful compound 4-isobutylacetophenone (IBAP) can be formed photochemically from the anti-inflammatory drug ibuprofen (IBP), upon direct photolysis (yield 25 ± 7%, μ ± σ), reaction with ·OH (yield 2.3 ± 0.1%) and reaction with triplet states of chromophoric dissolved organic matter, (3)CDOM* (yield 31 ± 4%). In the latter case, anthraquinone-2-sulphonate was used as CDOM proxy. The three processes would account for most of the photochemical transformation of IBP and IBAP in surface waters. IBAP formation from IBP involves the propanoic acid chain, which is more reactive than the aromatic ring as shown by quantum mechanical calculations. IBAP is expected to undergo slightly faster photochemical transformation than IBP in surface waters, with a modelled pseudo-first order rate constant that is higher by 1.5-1.9 times compared to IBP. Due to fairly high formation yields and depending on IBP emission scenarios, photochemical modelling suggests that IBAP could reach concentration values up to ~15% of IBP in surface waters, thus being a potentially important transformation intermediate. This issue prompts for the need of field studies that provide information on IBAP environmental occurrence, which is virtually unknown at the present moment.

Agrobacterium tumefaciens-mediated in planta seed transformation strategy in sugarcane

An efficient, reproducible and genotype-independent in planta transformation has been standardized for sugarcane using seed as explant. Transgenic sugarcane production through Agrobacterium infection followed by in vitro regeneration is a time-consuming process and highly genotype dependent. To obtain more number of transformed sugarcane plants in a relatively short duration, sugarcane seeds were infected with Agrobacterium tumefaciens EHA 105 harboring pCAMBIA 1304-bar and transformed plants were successfully established without undergoing in vitro regeneration. Various factors affecting sugarcane seed transformation were optimized, including pre-culture duration, acetosyringone concentration, surfactants, co-cultivation, sonication and vacuum infiltration duration. The transformed sugarcane plants were selected against BASTA(®) and screened by GUS and GFP visual assay, PCR and Southern hybridization. Among the different combinations and concentrations tested, when 12-h pre-cultured seeds were sonicated for 10 min and 3 min vacuum infiltered in 100 µM acetosyringone and 0.1 % Silwett L-77 containing Agrobacterium suspension and co-cultivated for 72-h showed highest transformation efficiency. The amenability of the standardized protocol was tested on five genotypes. It was found that all the tested genotypes responded favorably, though CoC671 proved to be the best responding cultivar with 45.4 % transformation efficiency. The developed protocol is cost-effective, efficient and genotype independent without involvement of any tissue culture procedure and can generate a relatively large number of transgenic plants in approximately 2 months.

Semisynthesis of mallotus B from rottlerin: evaluation of cytotoxicity and apoptosis-inducing activity

Mallotus B (2d) is a prenylated dimeric phloroglucinol compound isolated from Mallotus philippensis. There have been no reports on the synthesis or biological activity of this compound. In the present paper, a semisynthetic preparation of mallotus B is reported via base-mediated intramolecular rearrangement of rottlerin (1), which is one of the major constituents of M. philippensis. The homodimer "rottlerone" was also formed as one of the products of this base-mediated intramolecular reaction. Rottlerin (1), along with rottlerone (2c) and mallotus B (2d), was evaluated for cytotoxicity against a panel of cancer cell lines including HEPG2, Colo205, MIAPaCa-2, PC-3, and HL-60 cells. Mallotus B (2d) displayed cytotoxicity for MIAPaCa-2 and HL-60 cells with IC₅₀ values of 9 and 16 μM, respectively. Microscopic studies in HL-60 cells indicated that mallotus B (2d) induces cell cycle arrest at the G1 phase and causes defective cell division. It also induces apoptosis, as evidenced by distinct changes in cell morphology.

Synthesis, spectral and antimicrobial activity of Zn(II) complexes with Schiff bases derived from 2-hydrazino-5-[substituted phenyl]-1,3,4-thiadiazole and benzaldehyde/2-hydroxyacetophenone/indoline-2,3-dione

Zn(II) complexes have been synthesized by reacting zinc acetate with Schiff bases derived from 2-hydrazino-5-[substituted phenyl]-1,3,4-thiadiazole and 2-hydroxyacetophenone/benzaldehyde/indoline-2,3-dione. All these complexes are soluble in DMF and DMSO; low molar conductance values indicate that they are non electrolytes. Elemental analyses suggest that the complexes have 1:2 metal to ligands stoichiometry of the types [ZnL2(H2O)2](L=monoanionic Schiff bases derived from 2-hydrazino-5-[substituted phenyl]-1,3,4-thiadiazole and 2-hydroxyacetophenone/indoline-2,3-dione) [ZnL2(')(OOCCH3)2(H2O)2](L'=neutral Schiff bases derived from 2-hydrazino-5-[substituted phenyl]-1,3,4-thiadiazole and benzaldehyde), and they were characterized by IR, (1)H NMR, and (13)C NMR. Particle sizes of synthesized compounds were measured with dynamic light scattering (DLS) analyser which indicates that particle diameter are of the range ca. 100-200nm. All these Schiff bases and their complexes have also been screened for their antibacterial (Bacillus subtilis (B. subtilis), Escherichia coli (E. coli) and antifungal activities (Colletotrichum falcatum (C. falcatum), Aspergillus niger (A. niger), Fusarium oxysporium (F. oxysporium) Curvularia pallescence (C. pallescence). The antimicrobial activities have shown that upon complexation the activity increases.

Acaricidal potentials of active properties isolated from Cynanchum paniculatum and acaricidal changes by introducing functional radicals

This study evaluated the acaricidal activities of acetophenone and its derivatives for their potentials as natural acaricides using an impregnated fumigant bioassay against Dermatophagoides spp. and Tyrophagus putrescentiae . On the basis of the LD50 values against D. farinae, 3'-methoxyacetophenone (0.41 μg/cm(2)) was 89.9 times more toxic than DEET (36.87 μg/cm(2)), followed by 4'-methoxyacetophenone (0.52 μg/cm(2)), 2'-methoxyacetophenone (0.75 μg/cm(2)), 2'-hydroxy-5'-methoxyacetophenone (1.03 μg/cm(2)), 2'-hydroxy-4'-methoxyacetophenone (1.29 μg/cm(2)), acetophenone (1.48 μg/cm(2)), 2'-hydroxyacetophenone (1.74 μg/cm(2)), 2',5'-dimethoxyacetophenone (1.87 μg/cm(2)), 2',4'-dimethoxyacetophenone (2.10 μg/cm(2)), and benzyl benzoate (9.92 μg/cm(2)). In regard to structure-activity relationships between acaricidal activity and functional radicals (hydroxyl and methoxy groups) on the acetophenone skeleton, a monomethoxy group (2'-, 3'-, and 4'-methoxyacetone) on the acetophenone skeleton was more toxic than were the other groups (2',4'- and 2',5'-dimethoxyacetophenone, 2'- and 4'-hydroxyacetophenone, 2'-hydroxy-4'-methoxyacetophenone, 2'-hydroxy-5'-methoxyacetophenone, and 4'-hydroxy-3'-methoxyacetophenone). These results indicated that acaricidal activity against three mite species changed with the introduction of functional radicals (hydroxyl and methoxy groups) onto the acetophenone skeleton.

Improvement of pharmacokinetics behavior of apocynin by nitrone derivatization: comparative pharmacokinetics of nitrone-apocynin and its parent apocynin in rats

Apocynin, a potent inhibitor of NADPH-oxidase, was widely studied for activities in diseases such as inflammation-mediated disorders, asthma and cardiovascular diseases. In our recent study, a novel nitrone derivative of apocynin, AN-1, demonstrated potent inhibition to oxidative injury and to high expression of gp91^phox subunit of NADPH-oxidase induced by tert-butyl hydroperoxide (t-BHP) in RAW 264.7 macrophage cells, and displayed promising preclinical protective effect against lipopolysaccharide (LPS)-induced acute lung injury in rats. In this work, the pharmacokinetic behaviors of AN-1 in Sprague-Dawley rats with single intravenous and intragastric doses were investigated for further development. Furthermore, apocynin’s pharmacokinetics remain lacking, even though its pharmacological action has been extensively evaluated. The pharmacokinetics of parent apocynin were also comparatively characterized. A simple HPLC method was developed and validated to determine both AN-1 and apocynin in rat plasma. The chromatographic separation was achieved on an Agilent HC-C18 column (250 mm×4.6 mm, 5 µm) at an isocratic flow rate of 1.0 mL/min, with the mobile phase of methanol and water (53∶47, v/v) and the UV detection set at 279 nm. Good linearity was established over the concentration range of 0.1–500 µg/mL for AN-1 and 0.2–100 µg/mL for apocynin. The absolute recovery, precision and accuracy were satisfactory. Compared with the parent compound apocynin, AN-1 yielded a much longer T_1/2 (AN-1 179.8 min, apocynin 6.1 min) and higher AUC_0–t (AN-1 61.89 mmol/L·min, apocynin 2.49 mmol/L·min) after equimolar intravenous dosing (0.302 mmol/kg). The absolute bioavailability of oral AN-1 was 78%, but that of apocynin was only 2.8%. The significant improvement of pharmacokinetic behavior might be accounted for the effective pharmacodynamic results we documented for the novel nitrone derivative AN-1.

An investigation of solute-solvent interactions in binary liquid mixtures of 3'-methoxyacetophenone: using Raman spectroscopy and DFT calculations

Raman spectral measurements have been carried out for neat 3'-methoxy acetophenone (3'-MAP) and binary liquid mixtures of 3'-MAP in three solvents of different polarity. Also Density Functional Theory (DFT) geometry optimization and vibrational wavenumber calculation have been performed on monomer and dimer structures of 3'-MAP to analyze the experimentally observed Raman spectrum. Mulliken charge analysis has also been made on optimized geometries of 3'-MAP with solvents. The changes associated with the observed peak position, intensity and linewidth in the carbonyl stretching mode of 3'-MAP are explained as a consequence of intermolecular interactions between solute-solute and solute-solvent molecules. This analysis reports that the solute-solvent interaction is dominant in the case of binary liquid mixtures of 3'-MAP with ethanol compared to DMF and benzene.

Structural study, NCA, FT-IR, FT-Raman spectral investigations, NBO analysis and thermodynamic properties of 2',4'-difluoroacetophenone by HF and DFT calculations

In this work, the vibrational spectral analysis was carried out by FT-IR and FT-Raman spectroscopy in the regions of 4000-400 cm(-1) and 3500-100 cm(-1), respectively for 2',4'-difluoroacetophenone (DFAP). The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on Hartree-Fock (HF), density functional theory (DFT) using B3LYP and LSDA methods with 6-31G basis set combination. The mixing of the fundamental modes was determined with the help of potential energy distribution (PED). The energies of the frontier molecular orbitals have also been determined. Complete NBO analysis was also carried out using B3LYP/6-31G level of theory to find out the intramolecular electronic interactions and their stabilization energy. Thermodynamic properties of the title compound were calculated at the different temperature. Finally, the calculation results were applied to simulate FT-IR and FT-Raman spectra of the title compound which show good agreement with observed spectra.

[Study on the chemical constituent from the dichloromethane extract of the pine needle of Cedrus deodara (II)]

OBJECTIVE

To study the chemical constituents of the dichloromethane extract from pine needles of Cedrus deodara.

METHODS

The chemical constituents were isolated and purified from the dichloromethane extract of pine needles by chromatography on silica gel and Sephadex LH-20. Their structures were elucidated by analysis of spectral data and chemical properties.

RESULTS

Seven compounds were isolated and their chemical structures were identified as ferulic acid (1), osthole (2), beta-phenylacrylic acid (3), paeonol (4), beta-sitosterol (5), magnolol (6) and honokiol (7).

CONCLUSION

Compounds 1 - 4, 6 and 7 are isolated from this plant for the first time.