Complex Mixture Of Phenols Research Articles

OXIDATIVE EFFECTS OF MAHANARAYAN TAILA ON AMERICAN COCKROACH, PERIPLANETA AMERICANA L. (BLATTIDAE: BLATTODEA)

The American cockroach (Periplaneta americana), a prevalent household pest originating from tropical regions like India, poses a significant public health risk as a carrier of human pathogens. The present study investigated the effectiveness of ?Mahanarayan Taila (MT),? an herbal oil, as an alternative solution. The repellent activity of the oil and its impact on biomolecules such as lipids and proteins in cockroaches was determined. Cockroaches were exposed to sub-lethal concentrations of MT over 24, 48, 72, and 96 h to assess repellency. The oil at 1% concentration resulted in a 50% mortality of adults. Mortality data were analyzed using GraphPad software. The study revealed significant changes in lipid peroxide levels, correlating with the oil concentration, and a dose-dependent depletion in protein sulfhydryl levels alongside the formation of protein carbonyls. Behavioral changes were also documented, including a knockdown effect and the appearance of black residues on cockroaches. These findings highlight the potential of MT herbal oil as an effective and safer alternative for cockroach control. With its complex mixture of phenols, monoterpenes, and sesquiterpenes, MT shows promise for surface treatments or fumigation in cockroach control programs.. KEYWORDS :Lipid peroxidation, Mahanarayan Taila, Mortality, Oxidative stress, Periplaneta americana

Valorization potential of technical lignins from Norway spruce (Picea abies) via pyrolysis

Analytical pyrolysis (Py-GC/MS) on mg-scale of Norway spruce (Picea abies)-derived kraft lignin, ethanosolv lignin, and dried lignin-rich soda-anthraquinone (AQ) black liquors was studied at 500 °C to compare the valorization potential of these materials, focusing on the type and yield of condensable pyrolysis products. Of particular interest was the relatively selective formation of guaiacol (2-methoxyphenol) from the dried soda-AQ black liquors in contrast to the formation of complex phenolic product mixtures from the pyrolysis of the kraft and ethanosolv lignins. It was shown that this finding could be attributed to differences in composition and structure as was assessed by various NMR and 2D-GC/FID analyses. From a comparison between the analytical pyrolysis results and the results of Norway spruce-derived pyrolysis oils that were produced in earlier research with a state-of-the-art kg-scale bubbling fluidized bed pyrolysis reactor, it was concluded that analytical pyrolysis is suitable to predict the pyrolysis behavior of lignin also on a larger scale. However, it was found that the prediction of reliable product yields for larger-scale pyrolysis from the semi-quantitative analytical pyrolysis yield results was less accurate, mainly due to differences in process conditions, such as heating rate and hot-vapor-residence times leading to secondary degradation reaction of the individual monomers.

Valorization of Winemaking By-Products as a Novel Source of Antibacterial Properties: New Strategies to Fight Antibiotic Resistance.

The emergence of antibiotic-resistance in bacteria has limited the ability to treat bacterial infections, besides increasing their morbidity and mortality at the global scale. The need for alternative solutions to deal with this problem is urgent and has brought about a renewed interest in natural products as sources of potential antimicrobials. The wine industry is responsible for the production of vast amounts of waste and by-products, with associated environmental problems. These residues are rich in bioactive secondary metabolites, especially phenolic compounds. Some phenolics are bacteriostatic/bactericidal against several pathogenic bacteria and may have a synergistic action towards antibiotics, mitigating or reverting bacterial resistance to these drugs. Complex phenolic mixtures, such as those present in winemaking residues (pomace, skins, stalks, leaves, and especially seeds), are even more effective as antimicrobials and could be used in combined therapy, thereby contributing to management of the antibiotic resistance crisis. This review focuses on the potentialities of winemaking by-products, their extracts, and constituents as chemotherapeutic antibacterial agents.

Effect of Reaction Conditions on Catalytic and Noncatalytic Lignin Solvolysis in Water Media Investigated for a 5 L Reactor.

The high content of oxygen in the lignin polymer and the prevalence of phenolic functional groups make the conversion of lignin to fuels and value-added products with well-defined chemical properties challenging. The lignin-to-liquid process using a water/formic acid reaction medium has been shown to convert the lignin polymer to monomers with a molecular weight range of 300–600 Da. The bio-oil comprises a complex mixture of monomeric phenols, aromatics, and aliphatic hydrocarbons with a high H/C and low O/C ratio. This study investigates the effect of the stirring rate, level of loading, and catalyst at 305 and 350 °C in a 5 L pilot scale reactor. The oil yields are found to be highest for experiments conducted using the maximum stirring rate, maximum level of loading, and Ru/Al2O3 catalyst with yields of more than 69 wt % on lignin intake. Goethite as a catalyst does not show good conversion efficiency at either reaction temperatures. The carbon recovery is highest for products produced at 305 °C. Furthermore, results from solid phase extraction on a DSC-CN solid phase show that 65–92 wt % the bio-oils can be recovered as fractions separated based on polarity.

Characterization of bio-oil and biochar from pyrolysis of waste corrugated cardboard

As the most abundant municipal solid waste, corrugated cardboard (CCB) is a suitable resource for thermochemical conversion into various solid and liquid products. CCB samples were pyrolyzed at three temperatures (350, 400, and 450 °C) and their pyrolysis products (bio-oil and biochar) were characterized and analyzed. Thermogravimetric analysis (TGA) was utilized to study the thermal degradation behavior of CCB. CCB and biochar samples were subjected to proximate, ultimate, lipid and carbohydrates analyses, and Py–GCMS to characterize their chemical components. The highest biochar yield was 75% at 350 °C, and the highest bio-oil yield was 47% at 450 °C. The biochar physical and chemical properties were also assessed using calorific values, specific surface area, Fourier-transform infrared (FTIR) and Raman spectroscopies, and x-ray diffraction (XRD). Biochar was found to have low ash and nitrogen contents. The bio-oil was characterized by the combination of GCMS, high-performance liquid chromatography (HPLC), and electrospray ionization mass spectrometry (ESI–MS). The molar mass distribution and an estimate of monomer/oligomer ratio were determined from ESI-MS data. The bio-oil contained a complex mixture of pyrans, furans, phenols, and cyclopentenes. Levoglucoson was abundantly found in the bio-oil, suggesting the suitability of cardboard pyrolysis products for further processing into fuels.

Formic acid assisted liquefaction of lignin in water and ethanol, investigated for a 0.025 and a 5 L batch reactor: Comparison of yields and compositions of the products

Formic acid assisted conversion of lignin to liquids (LtL-process), where lignin is hydrodeoxygenated in a one-step conversion, produces bio-oils with a molecular weight range of 300–600 Da that comprise a complex mixture of monomeric phenols, e.g., phenol, cresol, guaiacol, catechol, etc., and more hydrogenated products. This paper addresses depolymerisation of lignin at small and large lab scales and includes characterisation of the products. Lignin conversion is performed using a 5 L stirred reactor and a 0.025 L unstirred reactor to evaluate the effect of increased volume and stirring on the oil yield and oil quality. The amount of oil yields is investigated for different types of lignin/lignin-rich residues, reaction temperatures (320–380 °C), reaction times (0.75–3 h) and reaction solvents (aqueous or ethanolic), and have been shown to be highest for the 0.025 L reactor. Furthermore, the relationship between the yields and reaction conditions are systematically explored using principal component analysis (PCA). For the Eucalyptus lignin-rich residue, ethanol tends to give higher oil yields (36–52 wt%) at most of the operating temperatures compared to water as reaction solvent (20–50 wt%). At both reaction scales and both solvent-systems, oil yields tends to decrease at reaction temperatures above 350 °C due to increased char formation. Reaction time does not seem to have any significant effect on oil yield at either scale. More than 40 wt% of the input lignin can be recovered as oil at 320 °C at both scales and solvent systems.

Analysis and optimisation of a novel “bio-brewery” approach: Production of bio-fuels and bio-chemicals by microwave-assisted, hydrothermal liquefaction of brewers’ spent grains

This work firstly explores the feasibility of using a novel microwave-assisted, catalysed, hydrothermal process for the valorisation of brewers’ spent grains (BSGs), examining the effects of the temperature (180–250 °C), pressure (50–130 bar), reaction time (0–2 h) and catalyst amount (Ni-Co/Al-Mg, 0–0.25 g cat/g biomass). This route turned out to be a very promising approach for the production of bio-fuels (bio-oil and bio-char) and platform chemicals (sugar rich aqueous solutions) in a single unit, helping the development of an innovative bio-refinery around BSGs. The overall conversion and the yields to gas, aqueous fraction and bio-oil varied by 31–68%, 10–33%, 9–48% and 4–14%, respectively. The bio-oil was made up a complex mixture of phenols (0–26%), ketones (0–80%), aldehydes (0–57%), carboxylic acids (0–18%) and nitrogen compounds (0–76%). The proportions of C, H, N and O in the bio-oil varied as follow: 15–61 wt%, 5–10 wt%, 1–6 wt% and 26–77 wt%, respectively, which shifted its higher heating value (HHV) between 9 and 27 MJ/kg. The liquid fraction comprised a mixture of DP > 6 oligosaccharides (67–98 C-wt.%), DP2-6 oligosaccharides (0–10 C-wt.%), saccharides (0.2–7 C-wt.%), carboxylic acids (0–7 C-wt.%) and furans (0–27 C-wt.%). The spent solid after the experiments resembled an energetic like bio-char product, whose proportions of C, H, O and N varied by 35–72 wt%, 4–8 wt%, 1–4 wt% and 18–57 wt% and its HHV shifted between 9 and 32 MJ/kg. The optimisation of the process revealed that using a temperature of 250 °C and a pressure of 125 bar for 2 h, it is possible to convert the original material into high-energy biofuels: (8%) bio-oil (26 MJ/kg) and (35%) bio-char (32 MJ/kg); together with a (31%) saccharide-rich (>99 C-wt.%) aqueous solution, thus converting this process into a very promising approach to achieve an environmentally-friendly and integral valorisation of brewers’ spent grains.

Matrix-free laser desorption ionization mass spectrometry as a functional tool for the analysis and differentiation of complex phenolic mixtures in propolis: a new approach to quality control.

Matrix-free laser desorption ionization (LDI) is a rapid and versatile technique for the ionization of small, UV-light-absorbing molecules. Indeed, many natural products such as polyphenols exhibit inherent LDI properties, potentially facilitating their detection from highly complex samples such as crude extracts. With this in mind, the present work thoroughly evaluated the potential of LDI as an analytical tool for the chemical profiling and differentiation of propolis samples obtained from different global regions. Propolis is a complex bee product containing, among others, significant amounts of phenolic constituents that may show LDI effects. The present work will demonstrate that LDI not only provides reproducible and highly specific fingerprint spectra for each of the tested samples, it further allows their clear differentiation by principal compound analysis (PCA). Contrary to classical analytical approaches such as LC- or GC-MS, LDI does not require time-consuming sample preparation and method optimization procedures. Thus, the technique represents a most interesting analytical tool and potent supplement to classic LC-MS for quality control of herbal pharmaceuticals and dietary supplements. Present results clearly support this approach and further suggest the use of LDI as a versatile tool for the automated analysis of large sample batches on an industrial scale. Graphical abstract ᅟ.

Hydrothermal Liquefaction of Macroalgae Enteromorpha prolifera to Bio-oil

Marine macroalgae Enteromorpha prolifera, one of the main algae genera for green tide, was converted to bio-oil by hydrothermal liquefaction in a batch reactor at temperatures of 220−320 °C. The liquefaction products were separated into a dichloromethane-soluble fraction (bio-oil), water-soluble fraction, solid residue, and gaseous fraction. Effects of the temperature, reaction time, and Na2CO3 catalyst on the yields of liquefaction products were investigated. A moderate temperature of 300 °C with 5 wt % Na2CO3 and reaction time of 30 min led to the highest bio-oil yield of 23.0 wt %. The raw algae and liquefaction products were analyzed using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, gas chromatography−mass spectrometry (GC−MS), and 1H nuclear magnetic resonance (NMR). The higher heating values (HHVs) of bio-oils obtained at 300 °C were around 28−30 MJ/kg. The bio-oil was a complex mixture of ketones, aldehydes, phenols, alkenes, fatty acids, esters, aromatics, and nitrogen-containing heterocyclic compounds. Acetic acid was the main component of the water-soluble products. The results might be helpful to find a possible strategy for use of byproducts of green tide as feedstock for bio-oil production, which should be beneficial for environmental protection and renewable energy development.

Oxidative Transformation of Natural and Synthetic Phenolic Mixtures by Trametes versicolor Laccase

The efficiency of Trametes versicolor laccase in the transformation of phenols (caffeic acid, catechol, hydroxytyrosol, methylcatechol, protocatechuic acid, syringic acid, m-tyrosol, 3-hydroxybenzoic acid, 3-hydroxyphenylacetic acid, 2,6-dihydroxybenzoic acid, 4-hydroxybenzaldehyde) usually present in waste water, such as that derived from an olive oil factory, was investigated. According to their response to 24 h laccase action the 11 phenolic compounds were classified in three groups: reactive (88-100% transformation), intermediate reactive (transformation lower than 50%), and recalcitrant (not transformed at all). The enzyme was able to transform the 11 substrates even when they were present in a mixture and also toward a phenolic extract from a Moroccan olive oil mill waste water (OMW) sample. The disappearance of protocatechuic, 3-hydroxyphenylacetic, and 2,6-dihydroxybenzoic acids, and 4-hydroxybenzaldehyde was enhanced whereas that of caffeic acid and m-tyrosol was depressed when the phenols were present in the mixture. A reduction of enzyme activity occurred in single and/or complex phenolic mixtures after enzymatic oxidation. No correspondence between phenol transformation and disappearance of enzymatic activity was, however, observed. The overall results suggest that laccases are effective in the transformation of simple and complex phenolic mixtures.

Ultrafiltration as alternative purification procedure for the characterization of low and high molecular-mass phenolics from almond skins

A combination of sample preparation (ultrafiltration) and analysis techniques is proposed for the characterization of complex phenolic mixtures such as extracts from almond ( Prunus dulcis (Mill.) D.A. Webb) skins. LC/ESI-MS analysis of the permeates obtained after ultrafiltration on semipermeable membranes (low molecular-mass phenolic fractions) allowed the identification of several benzoic acids and aldehydes, flavan-3-ol monomers and oligomers, and flavonol and flavanone glycosides in almond skins. MALDI-TOF and ESI-MS/MS analysis of the diafiltered concentrates (high molecular-mass phenolic fractions) demonstrated the presence of proanthocyanidin oligomers up to decamers, composed of (epi)afzelechin, (epi)catechin and (epi)gallocatechin units linked by C C bonds (type B) and by both C C and C O bonds (type A). This analytical protocol can be of utility in the study of low and high molecular-mass phenolic compounds in natural products.

Potential applications of immobilized bitter gourd ( Momordica charantia) peroxidase in the removal of phenols from polluted water

The potential applications of immobilized bitter gourd peroxidase in the treatment of model wastewater contaminated with phenols have been investigated. The synthetic water was treated with soluble and immobilized enzyme preparations under various experimental conditions. Maximum removal of phenols was found in the buffers of pH values 5.0–6.0 and at 40 °C in the presence of 0.75 mM H 2O 2. Fourteen different phenols were independently treated with soluble and immobilized bitter gourd peroxidase in the buffer of pH 5.6 at 37 °C. Chlorinated phenols and native phenol were significantly removed while other substituted phenols were marginally removed by the treatment. Phloroglucinol and pyrogallol were recalcitrant to the action of bitter gourd peroxidase. Immobilized bitter gourd peroxidase preparation was capable of removing remarkably high percentage of phenols from the phenolic mixtures. Significantly higher level of total organic carbon was removed from the model wastewater containing individual phenol or complex mixture of phenols by immobilized bitter gourd peroxidase as compared to the soluble enzyme. 2,4-dichlorophenol and a phenolic mixture were also treated in a stirred batch reactor with fixed quantity of enzyme for longer duration. The soluble bitter gourd peroxidase ceased to function after 3 h while the immobilized enzyme was active even after 6 h of incubation with phenolic solutions.

Current Technologies for the Thermo-Conversion of Biomass into Fuels and Chemicals

Pyrolysis and steam gasification processes for biomass conversion has proved to be economical in the production of chemicals, fuels, and polymers. The biomass pyrolysis oils are dark brown viscous liquids. The biomass gasification process is similar to processes used for many years by chemical and petrochemical manufacturers, including methanol, ammonia and ethylene producers. Bio-oils prepared by liquefaction of wood comprised a complex mixture of volatile organic acids, alcohols, aldehydes, ethers, esters, ketones, furans, phenols, hydrocarbons, and nonvolatile components. The oil yield was higher with the catalytic aqueous liquefaction than with the non-catalytic aqueous liquefaction.

Identification and Quantification of Caffeic and Rosmarinic Acid in Complex Plant Extracts by the Use of Variable-Temperature Two-Dimensional Nuclear Magnetic Resonance Spectroscopy

A combination of advanced nuclear magnetic resonance (NMR) methodologies for the analysis of complex phenolic mixtures that occur in natural products is described, with particular emphasis on caffeic acid and its ester derivative, rosmarinic acid. The combination of variable-temperature two-dimensional proton-proton double quantum filter correlation spectroscopy (1H-1H DQF COSY) and proton-carbon heteronuclear multiple quantum coherence (1H-13C HMQC) gradient NMR spectroscopy allows the identification and tentative quantification of caffeic and rosmarinic acids at 243 K in extracts from plants of the Lamiaceae family, without resorting to previous chromatographic separation of the components. The use of proton-carbon heteronuclear multiple bond correlation (1H-13C HMBC) gradient NMR spectroscopy leads to the complete assignment of the correlations of the spins of H2a and H3a with the ester and carboxyl carbons of rosmarinic and caffeic acid, even at room temperature, and confirms the results of the above methodology Quantitative results are in reasonable agreement with reverse phase HPLC measurements.

Methodology for Identification of Phenolic Acids in Complex Phenolic Mixtures by High-Resolution Two-Dimensional Nuclear Magnetic Resonance. Application to Methanolic Extracts of Two Oregano Species

Spectroscopic methodology in analyzing two-dimensional (2D) NMR spectra of a mixture of several phenolic compounds that occur in natural products is described. Particular emphasis has been given to the determination of scalar coupling connectivities by homonuclear 2D correlated spectroscopy (COSY), remote intraresidue connectivities by totally correlated spectroscopy (TOCSY), and spatially close but uncoupled 1H nuclei by homonuclear 2D nuclear Overhauser effect spectroscopy (NOESY/ROESY). Preliminary data to identify phenolic acids in the methanolic extracts from two oregano plants are also reported. Keywords: Oregano; phenolic acids; 1H NMR; COSY; TOCSY; NOESY/ROESY

Preliminary results from a field experiment investigating the fate of some creosote components in a natural aquifer

Creosote, a distillation product of coal tar, is made up of an extremely complex mixture of phenols and polycyclic aromatic compounds (PAC) which include polycyclic aromatic hydrocarbons (PAH) and nitrogen, sulphur and oxygen (NSO) containing heterocyclics. It is considered to be an environmental hazard. This report presents some preliminary results from a large field experiment that is evaluating the mobility, persistence and fate in groundwater of compounds present in coal tar creosote. This involved setting up a long-term field experiment where a limited plume of contaminated ground water was created by placing creosote into an extremely well characterized sand aquifer. The original creosote was dominated by PAH components with minor amounts of NSO containing PAC. The concentration of the dominant nitrogen heterocyclic (quinoline) was only 10% of the abundance of the major PAH components (naphthalene and phenanthrene). Analysis of groundwater samples collected 278 days after the emplacement of the creosote shows that with increasing distance from the source the concentration of naphthalene is reduced while that of quinoline increases, eventually becoming dominant. A similar trend was also observed for samples collected after 471 days and this can be related to the relative aqueous solubilities and mobility of the two compounds. Also observed in the outermost 471 day samples was the presence of quinolinone which is believed to be an aerobic metabolite of quinoline. Strategies for the final part of the project which involve cleaning up the Borden experimental site are briefly discussed in light of these results.

Groundwater Pollution Arising from the Disposal of Creosote Waste

ABSTRACTCreosote‐contaminated groundwater contains a complex mixture of phenols, aromatic hydrocarbons and nitrogen‐, sulphur‐ or oxygen‐containing heterocyclic, aromatic compounds. One of the most important factors that limits the spreading of these contaminants in groundwater aquifers is degradation by subsurface micro‐organisms.This paper gives an overview of the present knowledge about microbial degradation of creosote contaminants under aerobic and anaerobic conditions. Furthermore, various techniques for biological remediation of creosote‐contaminated groundwater are outlined. These techniques include enhancement of the native population of subsurface micro‐organisms to degrade the contaminants (in situ treatment) and withdrawal of the groundwater followed by treatment by various wastewater treatment processes (above‐ground treatment).

Study of retention behavious of alkylphenols in straight- and reversed-hase liquid chromatography and application to the analysis of complex phenolic mixtures in conjuction with gas chromatography

A seris of alkyl-substituted phenols were chromatographed on four liquid chromatographic columns: three straight-phase systems on nitrile phases and one reversed-phase system on octadecylsilane. On the nitrile phases, the alkylphenols are eluted in the order di- ortho-, mono- ortho- and non- ortho-substituted phenols, while on the reversed-phase system, it is primarily the number of substituted alkyl carbon atoms that determined the retention. Two-column plots, i. e., log k′ on reversed phase versus log k′ on straight phase, give three well separated straight lines representing the di-, mono- and non- ortho-substituted phenols. Combination of straight- and reversed-phase liquid chromatography and capillary column gas-liquid chromatography provides an effective means for the separation and identification of complex mixtures of alkylphenols.

Production of a metallurgical coke from the resin of wallaba wood (eperua sp.)

AbstractThe wood of the wallaba tree (Eperua sp.) of British Guiana contains a high proportion of an alcohol‐soluble resin of a phenolic type. It is shown that this resin can be converted by controlled destructive distillation into a metallurgical coke of high purity and good physical properties. The volatile products of the distillation include a complex mixture of phenols which has useful fungicidal properties, and a combustible gas.