QSAR Study of Halogen Phenols Toxicity to Tetrahymena Pyriformis

Structural parameters of 22 halogen phenols were computed at four levels using Hartree-Fock and DFT methods. Based on the experimental data of the acute toxicity to Tetrahymena pyriformis （-lgEC_50）, three-parameter （energy of the lowest unoccupied molecular orbital （E_LUMO）, the molecular volume （V）, and the lowest negative charge （Q_min）） dependent equations were developed using structural parameters as theoretical descriptors. Especially, -lgEC_50dependent equation calculated at the B3LYP/6-31G^＊＊ level is more advantageous than the others in view of their correlation and predictive abilities. This dependent equation was validated by variance inflation factors （VIF） and t-test methods. Upon comparison, the predictive abilities of our work are all more advantageous than those calculated from the semi-empirical PM3 method.

Correlation Study of Toxicity of Substituted Phenols to River Bacteria and Their Biodegradability in River Water

To study the correlation of toxicity with biodegradability （BODT） in order to promote QSBR development and understand the degradation mechanism. Methods Toxicity of substituted phenols to river bacteria was determined by the turbidities that were measured using a spectrophotometer （UV-190） at 530 nm against a blank control. The biodegradability of substituted phenols was expressed as BODT and the DO concentrations were determined by the iodometric titration method. Results The BODT and toxicity（log 1/IC50） of 12 substituted phenols to bacteria from the Songhua River were determined respectively. The correlation of biodegradability with toxicity was developed： BODT=8.21 （±2.22） pKa -32.44 （±8.28） log 1/IC50 ＋89.04 （±38.20）, n=12, R^2=0.791, R^2（adj）=0.745, SE=9.134, F=17.066, P=0.001. Conclusion The BODT of substituted phenols was influenced by their toxicity and the ionization constant pKa. The stronger the toxicity, the less readily the compound was degraded by river bacteria.

Quantification of Total Phenols, Total Flavonoids, Total Anthocyanins and Evaluation of Antioxidant and Antiradical Activities of Detarium Senegalense Extracts from Chad

The aim of the present work is to assess the value of Detarium Senegalense by determining the content of total phenols, total flavonoids and total anthocyanins, and by evaluating the free radical scavenging activity of Detarium Senegalense extracts. For this purpose, sequential extraction using solvents of increasing polarity was essential. The various extracts obtained underwent phytochemical and biochemical analyses. Phytochemical screening revealed the presence of flavonoids, alkaloids, tannins, polyphenols, anthocyanins and steroids/terpenes. Quantitative analysis of total polyphenols, total flavonoids and total anthocyanins yielded the following results: total flavonoids (0.803 ± 0029 mg EQ/100g P for acetone extract of roots and 0.871 ± 0.401 mg EQ/100g P for methanol extract of leaves);total polyphenols (23.298 ± 12.68 mg EAG/100g P for acetone extract of roots and 24.69 ± 0.49 401 mg EAG/100g P for methanol extract of leaves);total monomeric anthocyanins (44.697 ± 0.939 mg EC3G/100g P and 16.699 ± 0.193 mg EC3G/100g P respectively for acetone and methanol extracts of stem bark). DPPH free radical scavenging activity was 1.674 ± 0.023 mg/mL for the acetone extract and 0.934 ± 0.24 mg/mL for the methanol extract of roots. .

Studies on Recovery Efficiencies of Phenols from Phenol Fraction Using Alkali Treatment

Experiments were conducted for the extraction of phenols from the phenol fraction obtained from the coal tar distillate. The phenol fraction for the present investigation has been procured from Visakhapatnam Steel Plant, Visakhapatnam whose composition is known. The phenol fraction from coal tar distillate can be treated for extracting phenols using caustic soda. An attempt has been made to find out whether the existing practice of using only 8%-15% can be modified by increasing the strength of sodium hydroxide and also explore the possibilities of substituting the sodium hydroxide with KOH as an extractant. The different streams of liquids obtained during experimentation have been analyzed by gas chromatograph. Salient features of the study are that higher concentrations of the alkali significantly improved the separation efficiencies of phenols and also regenerate the phenolate with higher phenol content. Increase in the alkali strength has greatly improved the separation as well as the phenol content in the regenerated phenols. Disposal of effluents containing phenols may lead to environmental problem of ground water pollution and the study throws a light on the removal of phenols from the effluents to the extent possible by using higher strength alkali solutions.

Extraction Condition Optimization and Identification of Phenols from Lonicerae flos

Polyphenols were obtained from the natural dried Lonicerae flos by ultrasound-assisted extraction with ethanol as the solvent.Single factor experiment and response surface methodology were employed to optimize the extraction conditions.Ultra-performance liquid chromatrography(UPLC)-tandem mass spectrometry(MS/MS)was employed to identify polyphenols based on the plant widely targeted metabolomics database in a qualitative and quantitative manner.The results showed that the optimal extraction conditions for total phenols from Lonicerae flos were ultrasound-assisted extraction with a solid-to-liquid ratio of 10∶1 g/mL and 57%ethanol at 70 W and 60°C for 11 min.The yield of total phenols extracted under the optimal conditions reached 71.08 mg/g.The phenols in Lonicerae flos were mainly chlorogenic acid isomers,and the flavonoids were mainly nobiletin,galuteolin,and homoarbutin.

Study of Quantitative Structure-retention Relationship for Substituted Phenols

Quantum chemistry parameters of 20 substituted phenols were computed at the 6- 31G＊ level using DFT method. Based on theoretical linear solvation energy theory, the correlation equation that can predict the retention index （Ri） was developed using structural parameters of 15 substituted phenols with experimental data as theoretical descriptors, and the conventional correlation coefficient （R^2） is 0.9885. The correlation degree of each independent variable in the model was validated by variance inflation factors （VIF） and t-test. Cross-validation indicates that the model possesses high predicting ability. The correlation and predicting ability of the Ri equation are both more advantageous than those based on orientating group index, connectivity index, and topological index method. In addition, RI values of 5 compounds without experimental data were predicted with the model.

Hollow ZIF-67-derived Co@N-doped carbon nanotubes boosting the hydrogenation of phenolic compounds to alcohols

The selective hydrogenation of highly toxic phenolic compounds to generate alcohols with thermal stability,environmental friendliness,and non-toxicity is of great importance.Herein,a series of Co-based catalysts,named Co@NCNTs,were designed and constructed by direct pyrolysis of hollow ZIF-67(HZIF-67)under H_(2)/Ar atmosphere.The evolution of the catalyst surface from the shell layer assembled by ZIF-67-derived particles to the in situ-grown hollow nitrogen-doped carbon nanotubes(NCNTs)with certain length and density is achieved by adjusting the pyrolysis atmosphere and temperature.Due to the synergistic effects of in situ-formed hollow NCNTs,well-dispersed Co nanoparticles,and intact carbon matrix,the as-prepared Co@NCNTs-0.10-450 catalyst exhibits superior catalytic performance in the hydrogenation of phenolic compounds to alcohols.The turnover frequency value of Co@NCNTs-0.10-450is 3.52 h^(-1),5.9 times higher than that of Co@NCNTs-0.40-450 and 4.5 times higher than that of Co@NCNTs-0.10-550,exceeding most previously reported non-noble metal catalysts.Our findings provide new insights into the development of non-precious metal,efficient,and cost-effective metal-organic framework-derived catalysts for the hydrogenation of phenolic compounds to alcohols.

Screening for Antioxidant Phenolic Compounds from Polygonum capitatum

[Objectives]To discover antioxidant natural products from the famous Hmong medicinal plant Polygonum capitatum.[Methods]The antioxidant activities of the isolated components were evaluated by ABTS and DPPH assays.[Results]A total of 27 free phenolics were isolated form P.capitatum.Then the in vitro antioxidant potential of these components was evaluated according to the DPPH and ABTS radical scavenging assays.Among them,five compounds(13,14,17,23,and 25)showed most significant ABTS radical-scavenging activity(IC 50 values of 3.81-15.09μg/mL).And 12 components(1,2,6,7,9,12,13,14,16,17,23,and 25)showed notable radical scavenging activity against DPPH(inhibition rates>88%).[Conclusions]Most of the above bioactive compounds were reported for the first time.

Fate of polyphenols in pili(Canarium ovatum Engl.) pomace after in vitro simulated digestion

Objective: To evaluate the stability and bioavailability of polyphenols in pili(Canarium ovatum Engl.) pomace during simulated in vitro digestion.Methods: Freeze-dried pili pomace was subjected to in vitro digestion simulating conditions in the stomach, small intestine and colon. Total polyphenols, anthocyanins, fl avonoids and condensed tannins, and its antioxidant activity – 1,1-diphenyl-2-picrylhydrazyl, 2,20-azinobis-3-ethylbenzothiozoline-6-sulfonic acid, and ferric reducing antioxidant power were measured using standard spectrophotometric methods.Results: In vitro digestion of pili pomace resulted in reduction of phenolic compounds.Condensed tannins and anthocyanins were released in the gastric and intestinal stages,while total polyphenols and flavonoids after fermentation simulating colonic conditions.Antioxidant values of the bioavailable fractions showed that more than 90% of activity was lost during simulated digestion.Conclusions: Findings indicate that pili pomace is a promising functional ingredient for food and dietary supplements which can furnish potentially bioavailable phenolic antioxidants to the body.

Quantitative structure retention relationship studies for predicting relative retention times of chlorinated phenols on gas chromatography

A new method of quantitative structure retention relationship(QSRR) studies was reported for predicting gas chromatography(GC) relative retention times(RRTs) of chlorinated phenols (CPs) using a DB 5 column. Chemical descriptors were calculated from the molecular structure of CPs and related to their gas chromatographic RRTs by using multiple linear regression analysis. The proposed model had a multiple square correlation coefficient R 2=0.970, standard error SE =0.0472, and significant level P =0.0000. The QSRR model also reveals that the gas chromatographic relative retention times of CPs are associated with physicochemical property interactions with the stationary phase,and influenced by the number of chlorine and oxygen in the CP melecules.

Space Group Distribution in Substituted Phenols

Analysis on the space group distribution in 78 substituted phenols re-vealed its unusual high frequencies in groups with non-centrosymmetry or polar axis orhigher symmetry or Z' > 1. Based on the characteristics of intermolecular H-bondsformed by two OH groups,the space group distribution could be rationalized well.

Flow Injection Amperometric Determination of Phenol and Chlorophenols at Single Wall Carbon Nanotube Modified Glassy Carbon Electrode

Single wall carbon nanotube modified glassy carbon electrode (SWCNT/GCE) was used for flow-injection analysis (FIA) for phenolic compounds (phenol (P), 4-chlorophenol (CP), 2,4-dichlorophenol (DCP), 2,4,6-trichlorphenol (TCP) and pentachlorophenol (PCP)). Experimental variables such as the detection potential, flow rate and pH of the carrier solution, 0.1 M sodium acetate, were optimized. Under these conditions, the designed electrode showed a very good performance for the amperometric measurements, with no need to apply a cleaning or pre-treatment procedure. The operational stability was tested with 20 repetitive injections of each analyte and was found to be good. The analytical performance of the SWCNT/GCE electrode under flow through conditions was tested and was found to be impressive. When it is compared with other enzymatic and non-enzymatic sensors, it shows wider dynamic range for the detection of phenolic compounds with low limits of detection. These results suggest that the method is quite useful for monitoring and analyzing phenols and chlorophenols.

A Study of the Behavior of Alkyl Side Chains Phenols and Arenes in Polar and Nonpolar GC Stationary Phases

Gas chromatographic measurements of the relative retention times of alkyl-substituted arenes and phenols on capillary columns at temperatures of 125 – 140°C have shown that logarithms of retention times increase bilinearly with the number of carbon atoms in the molecule. It was found that in a high density stationary phase, the longer alkyl side chains of compounds in question are subject to cyclization as a result of the resistance force of this phase affecting molecules during their thermal and diffusion motion. Consequently, common conventional aromatic-aliphatic molecules become new molecules with quasi-alicyclic rings. In comparison with the conventionally conceived molecules, the resulting aromatic–quasi-alicyclic molecules are characterized by rather different, possibly even completely different non-covalent interactions between the molecules, which then affect the retention characteristics. Moreover, cyclization facilitates the mixing of n-alkyl arenes and n-alkyl phenols with high-molecular stationary phases, because the thermodynamic condition for mixing is better fulfilled.

Structural derivatization strategies of natural phenols by semi-synthesis and total-synthesis

Structural derivatization of natural products has been a continuing and irreplaceable source of novel drug leads.Natural phenols are a broad category of natural products with wide pharmacological activity and have offered plenty of clinical drugs.However,the structural complexity and wide variety of natural phenols leads to the difficulty of structural derivatization.Skeleton analysis indicated most types of natural phenols can be structured by the combina-tion and extension of three common fragments containing phenol,phenylpropanoid and benzoyl.Based on these fragments,the derivatization strategies of natural phenols were unified and comprehensively analyzed in this review.In addition to classical methods,advanced strategies with high selectivity,efficiency and practicality were empha-sized.Total synthesis strategies of typical fragments such as stilbenes,chalcones and flavonoids were also covered and analyzed as the supplementary for supporting the diversity-oriented derivatization of natural phenols.

Three New Phenolic Glycosides from the Fertile Sprouts of Equisetum arvense

Three new phenolic glycosides, named as equisetumoside A (3-methoxy-11,12-dihydroxy-phenylhexane-9- one-4-O-beta -D-glucopyranoside), equisetumoside B (3-methoxy-4,11-dihydroxy-phenylhexane-9-one12-O-beta -D-glucopyranoside) and equisetumoside C ( cis-ferulic acid potassium salt 4-O-beta -D-glucopyranoside) were isolated from the water-soluble extract of fertile sprouts of Equisetum, arvense L. (Equisetaceae), together with uridine, inosine, 2'-deoxyinosine, 2'-deoxycytidine, tryptophan, thymidine, 5-carboxy-2'-deoxyuridine, coniferin, and kaempferol 3-O-beta -D-sophoroside-7-O-beta -D-glucopyranoside. Their structures were elucidated by spectroscopic analysis and chemical transformation.

Differences in Phenolic Compounds and Related Enzyme Activities between 2 Eucalyptus Species

[Objective] The aim was to provide theoretical basis for speeding up the popularization of Eucalyptus dunnii.[Method] Differences in phenolic compounds and related enzyme activities between hard rooting E.dunnii and easily rooting E.urophylla×E.grandis clone （U9） were studied.[Result] There were significant differences in contents of phenolic compounds and activities of indole acetic acid oxidase （IAAO）,andperoxidase （POD） and polyphenol oxidase （PPO） between the two Eucalyptus species.Compared with U9,contents of phenolic compounds and POD activity of E.dunnii cuttings were relatively high,while activities of IAAO and PPO were relatively low.[Conclusion] More phenolic compounds and the differences in related enzyme activities might be the major factors to result in hard rooting of E.dunnii cuttings.

In-situ reactive compatibilization of HDPE/GTR blends by dicumyl peroxide and phenolic resin without catalyst

In-situ reactive compatibilization of high-density polyethylene （HDPE）/ground tire rubber （GTR） blends by dicumyl peroxide （DCP） and HY-2045 - a kind of thermoplastic phenolic resin without catalyst was investigated by studying the mor-phology, stress and strain behavior, dynamic mechanical properties and crystallization performance of the blends. Scanning e-lectron microscopy （SEM） results show that there are a lot of fibrous materials distributing in the interface, which connects the dispersed phase with the matrix and obtains better interfacial strength for prominent mechanical properties. The addition of compatibilizers results in the decrease of crystallinity of the blends and the disappearance of an obvious yield phenomenon, which was proved by the differential scanning calorimeter （DSC） test and X-ray diffraction （XRD） characterization Although the crystallinity of the blends decreases,the tensile strength and tensile strain of the blends significantly increases, especially for the HDPE/GTR/DCP/HY-2045 blends, which is possibly attributed to the good compatibility of the blends owing to the in-situ interface crosslinking. In addition, it is found that the compatibilizing HDPE/GTR blends shows a higher tan^ peak temperature and a broaden transition peak for GTR phase.

Synergistic degradation of phenols by bimetallic CuO-Co_3O_4@γ-Al_2O_3 catalyst in H_2O_2/HCO_3^- system

The development of new catalytic techniques for wastewater treatment has long attracted much attention from industrial and academic communities.However,because of catalyst leaching during degradation,catalysts can be short lived,and therefore expensive,and unsuitable for use in wastewater treatment.In this work,we developed a bimetallic CuO-Co3O4@γ-Al2O3 catalyst for phenol degradation with bicarbonate-activated H2O2.The weakly basic environment provided by the bicarbonate buffer greatly suppresses leaching of active Cu and Co metal ions from the catalyst.X-ray diffraction and X-ray photoelectron spectroscopy results showed interactions between Cu and Co ions in the CuO-Co3O4@γ-Al2O3 catalyst,and these improve the catalytic activity in phenol degradation.Mechanistic studies using different radical scavengers showed that superoxide and hydroxyl radicals both played significant roles in phenol degradation,whereas singlet oxygen was less important.

Electrochemical Synthesis of Phenol-aniline Copolymerization Coating on 304 Stainless Steel Anodes and Coating Microstructure Analysis

Electrochemical copolymerization of phenol and aniline was achieved on 304 stainless steel anodes in neutral water solution with an electrolyte of Na2SO4O4. Compared with pit corrosion potential of different copolymer coatings, the best solution composition was 0.09 mol/L phenol and 0.01 mol/L aniline. Through infrared spectrum analysis, polyaniline structure was proved in phenol-aniline copolymer, as well as more side chains. Scanning electron microscope was used to analyze microstructure of copolymer coating, taking advantage of part solubility of phenol-aniline eopolymer in tetrahydrofuran, the bifurcate network structure was observed. The copolymer coating microstructure was summarized, compared with the performance of polyphenol coatings, the reasons of corrosion resistance enhancement with the addition of aniline in electropolymerization reaction was assumed as well.