Fatty Carboxylic Acids Research Articles

PH-Responsive Nanostructures Based on Surface Active Fatty Acid-Protic Ionic Liquids for Imiquimod Delivery in Skin Cancer Topical Therapy.

For topical treatment of skin cancer, the design of pH-responsive nanocarriers able to selectively release the drug in the tumor acidic microenvironment represents a reliable option for targeted delivery. In this context, a series of newly synthesized surface-active fatty acid-protic ionic liquids (FA-PILs), based on tetramethylguanidinium cation and different natural hydrophobic fatty acid carboxylates, have been investigated with the aim of developing a pH-sensitive nanostructured drug delivery system for cutaneous administration in the skin cancer therapy. The capability of FA-PILs to arrange in micelles when combined with each other and with the non-ionic surfactant d-α-Tocopherol polyethylene glycol succinate (vitamin E TPGS) as well as their ability to solubilize imiquimod, an immuno-stimulant drug used for the treatment of skin cancerous lesions, have been demonstrated. The FA-PILs-TPGS mixed micelles showed pH-sensitivity, suggesting that the acidic environment of cancer cells can trigger nanostructures’ swelling and collapse with consequent rapid release of imiquimod and drug cytotoxic potential enhancement. The in vitro permeation/penetration study showed that the micellar formulation produced effective imiquimod concentrations into the skin exposed to acid environment, representing a potential efficacious and selective drug delivery system able to trigger the drug release in the tumor tissues, at lower and less irritating drug concentrations.

Fatty acid-peptide-bioconjugated micellar nanocarrier as a new delivery system for l-asparaginase: multi-criteria optimization, characterization, and pharmacokinetic study

l-Asparaginase-fatty acid bioconjugate was prepared by coupling the carboxyl group of fatty acids to NH2 groups of lysine of the enzyme. In this study, the physicochemical properties of l-asparaginase were modified by incorporating surfactant with this amphiphilic structure. The preparation process of micellar nanocarrier was optimized by a systematic multi-criteria optimization approach in terms of particle size and enzyme activity. The final particle size, PDI, and enzyme activity were 387.6 ± 9.8 nm, 0.341 ± 0.031, and 92.1 ± 1.3%, respectively. Results are in an optimum condition. Furthermore, results showed that the optimized formulation is more resistant to proteolysis, is more stable at different pH (6.5 to 10), and has prolonged plasma half-life (56.8 h) in comparison to the native enzyme. Also, the longevity in the circulation by micellar nanocarriers was confirmed by the data on the pharmacokinetic study. This method can be used as a suitable method to provide a new formulation of l-asparaginase for the treatment of related diseases. Graphical abstract

Insights into the composition of ancient Egyptian red and black inks on papyri achieved by synchrotron-based microanalyses

A hitherto unknown composition is highlighted in the red and black inks preserved on ancient Egyptian papyri from the Roman period (circa 100 to 200 CE). Synchrotron-based macro-X-ray fluorescence (XRF) mapping brings to light the presence of iron (Fe) and lead (Pb) compounds in the majority of the red inks inscribed on 12 papyrus fragments from the Tebtunis temple library. The iron-based compounds in the inks can be assigned to ocher, notably due to the colocalization of Fe with aluminum, and the detection of hematite (Fe2O3) by micro-X-ray diffraction. Using the same techniques together with micro-Fourier transform infrared spectroscopy, Pb is shown to be associated with fatty acid phosphate, sulfate, chloride, and carboxylate ions. Moreover, micro-XRF maps reveal a peculiar distribution and colocalization of Pb, phosphorus (P), and sulfur (S), which are present at the micrometric scale resembling diffused "coffee rings" surrounding the ocher particles imbedded in the red letters, and at the submicrometric scale concentrated in the papyrus cell walls. A similar Pb, P, and S composition was found in three black inks, suggesting that the same lead components were employed in the manufacture of carbon-based inks. Bearing in mind that pigments such as red lead (Pb3O4) and lead white (hydrocerussite [Pb3(CO3)2(OH)2] and/or cerussite [PbCO3]) were not detected, the results presented here suggest that the lead compound in the ink was used as a drier rather than as a pigment. Accordingly, the study calls for a reassessment of the composition of lead-based components in ancient Mediterranean pigments.

Chemical Characterisation of the Floral Oil of the Murici (Byrsonima sericea): Discovering the Constituents Used in Reproduction by Oil-Collecting Bees

The recent decline in population of generalist bees such as those of the genera Apis and Bombus has shown the need to breed and manage a larger number of bee species. Among the species with potential use for agricultural pollination in the Neotropics, a peculiar small group has specialised in collecting floral oil. Therefore, the aim of this study was to analyse the chemical profile and to identify the main constituents of the floral oil of the nance (Byrsonima sericea), an abundant species in the Northeast of Brazil and widely used by oil-collecting bees. A sample of 400 flowers of the nance were collected between October 2017 and January 2018. The samples were derivatised (MSTFA) and analysed by gas chromatography-mass spectrometry in a Model 7890B GC Gas Chromatograph System coupled to a Model 5977A MSD mass spectrometer. The compounds were separated using an HP-5ms capillary column and identified by comparing the mass spectra with the National Institute of Standards and Technology (NIST) database, and by comparison of the retention indices (RI). From the chromatographic analysis, it was possible to identify 23 constituents, especially fatty acids and carboxylic acids. The results indicate the presence of tricosanoic acid, palmitic acid and heneicosanoic acid as the main constituents of the oil under study. There is still a need for studies that would better explain the relationship of these constituents with the bees that use the oil.

Biofuel from Hydroprocessing Fish Oil

This paper deals with the hydroprocessing of Fish Oil (FO) as a source to produce biofuel. The hydrotreating experiments were performed at 380�C and 50bar pressure over the CoMo/Al2O3 and CoMoRe/Al2O3 catalysts. Through hydrogenation of double bonds and carboxyl groups of Fatty Acids (FAs), accompanied by secondary hydrocracking and isomerization reactions, there results a mixture of normal & isoparaffin with 13-22 carbon atoms per molecule with physicochemical characteristics similar to diesel fuel. The hydrotreatment of Straight Run Gas Oil (SRGO) mixed with 5% and 10% (FO) was also studied. The research focuses on the influence of the SRGO-FO ratio and of the catalyst type on the yields and the physiochemical properties of the obtained biofuel. The results show that the hydrotreatment of FO and of SRGO-FO mixtures is an alternative for biofuel production with characteristics similar to diesel fuel.

Hydrothermal Oxidation of Polyethylene (PE) Plastic to Short-chain Fatty Acids (C1 - C5)

In most of the past studies on disposal of waste plastic, due to the irreversible hazards for human environmental health (incineration), and the strict requirements of reaction conditions (pyrolysis, gasification), the cost of disposal and research also increases. In this study, we converted waste polyethylene (PE) plastic into high value-added organic products by high-temperature water (HTW) to obtain C1 to C5 short-chain fatty carboxylic acids (formic acid, acetic acid, propionic acid, butyric acid and valeric acid). In addition, the reaction parameters (temperature, time, oxidant amount, pH) were investigated under hydrothermal conditions, and the yield for PE to short-chain fatty acids (C1 -C5) was optimized to 20%. Then the concentration of TOC and IC in the solution was used to measure the conversion and degradation of PE. In addition, the oil phase and solid residue after the reaction were also discussed in this research.

PRODUCTION OF CHELATE POLYMER-CONTAINING MICROFERTILIZERS BASED ON HUMIC ACID AND AMMOPHOS

The present article considers the production process of chelate polymer-containing micro fertilizers based on the humic acid obtained at the decomposition of a coal waste of the Lenger deposit (Kazakhstan) and etherified derivatives of hydrolyzed polyacrylonitrile (EDPAN). The chemical composition of the initial components and produced polymer-containing micro fertilizer determined using scanning electron microscopy, differential thermal and infrared analysis is given. To improve the quality of the fertilizer produced, boric acid, copper sulphate, iron sulphate and ammonium molybdate were added as microelements and the EDPAN as a chelation agent. In the course of the research, it was found that EDPAN acts as a chelation agent owing to the content of carboxyl groups of fatty acids and increases the assimilability of microelements by plants. Also, the elemental analysis showed that the introduction of EDPAN into the mixture promotes the formation of a granular crystalline structure of the chelate polymer-containing micro fertilizers. The micro fertilizers produced are characterized by a high content of humic substances, which participate in the soil structurization, accumulation of macro and micronutrients in the assimilable form and are intended for raising the level of crop yield.

Aryl urea substituted fatty acids: a new class of protonophoric mitochondrial uncoupler that utilises a synthetic anion transporter.

Respiring mitochondria establish a proton gradient across the mitochondrial inner membrane (MIM) that is used to generate ATP. Protein-independent mitochondrial uncouplers collapse the proton gradient and disrupt ATP production by shuttling protons back across the MIM in a protonophoric cycle. Continued cycling relies on the formation of MIM-permeable anionic species that can return to the intermembrane space after deprotonation in the mitochondrial matrix. Previously described protonophores contain acidic groups that are part of delocalised π-systems that provide large surfaces for charge delocalisation and facilitate anion permeation across the MIM. Here we present a new class of protonophoric uncoupler based on aryl-urea substituted fatty acids in which an acidic group and a π-system are separated by a long alkyl chain. The aryl-urea group in these molecules acts as a synthetic anion receptor that forms intermolecular hydrogen bonds with the fatty acid carboxylate after deprotonation. Dispersal of the negative charge across the aryl-urea system produces lipophilic dimeric complexes that can permeate the MIM and facilitate repeated cycling. Substitution of the aryl-urea group with lipophilic electron withdrawing groups is critical to complex lipophilicity and uncoupling activity. The aryl-urea substituted fatty acids represent the first biological example of mitochondrial uncoupling mediated by the interaction of a fatty acid and an anion receptor moiety, via self-assembly.

The JcWRKY tobacco transgenics showed improved photosynthetic efficiency and wax accumulation during salinity

Salinity is one of the major factors negatively affecting crop productivity. WRKY transcription factors (TFs) are involved in salicylic acid (SA) mediated cellular reactive oxygen species homeostasis in response to different stresses, including salinity. Therefore, the effect of NaCl, NaCl + SA and SA treatments on different photosynthesis-related parameters and wax metabolites were studied in the Jatropha curcas WRKY (JcWRKY) overexpressing tobacco lines. JcWRKY transgenics showed improved photosynthesis rate, stomatal conductance, intercellular CO2 concentration/ambient CO2 concentration ratio (Ci/Ca ratio), electron transport rate (ETR), photosynthesis efficiency (Fv/Fm), photochemical quenching (qP), non-photochemical quenching (NPQ) and quantum yield of PSII electron transport (ΦPSII) in response to salinity stress, while exogenous SA application had subtle effect on these parameters. Alkane, the major constituent of wax showed maximum accumulation in transgenics exposed to NaCl. Other wax components like fatty alcohol, carboxylic acid and fatty acid were also higher in transgenics with NaCl + SA and SA treatments. Interestingly, the transgenics showed a higher number of open stomata in treated plants as compared to wild type (WT), indicating less perception of stress by the transgenics. Improved salinity tolerance in JcWRKY overexpressing tobacco transgenics is associated with photosynthetic efficiency and wax accumulation, mediated by efficient SA signalling. The transgenics showed differential regulation of genes related to photosynthesis (NtCab40, NtLhcb5 and NtRca1), wax accumulation (NtWIN1) and stomatal regulation (NtMUTE, NtMYB-like, NtNCED3-2 and NtPIF3). The present study indicates that JcWRKY is a potential TF facilitating improved photosynthesis with the wax metabolic co-ordination in transgenics during stress.

Nannochloropsis Extract-Mediated Synthesis of Biogenic Silver Nanoparticles, Characterization and In Vitro Assessment of Antimicrobial, Antioxidant and Cytotoxic Activities.

Objective:To investigate the biogenic synthesis of silver nanoparticles (AgNPs) using partially purified ethyl acetate extract of Nannochloropsis sp. hexane (EAENH) fraction of microalga. Methods:The green synthesis of AgNPs was confirmed with UV-Vis spectrum which shows the surface plasmon resonance (SPR) at 421 nm. Fourier Transform Infrared Spectra (FTIR) presented the involvement of functional groups like carboxyl groups of fatty acids, tetraterpenoids of xanthophylls, hydroxyl groups of polyphenols, carbonyl and amide linkage of proteins in the AgNP synthesis. Gas Chromatography-Mass Spectrometry analysis (GCMS) revealed that phytochemicals like octadecanoic acid and hexadecanoic acid imply in capping, bioreduction, and stabilization of AgNps.Result:High-resolution Transmission electron microscope (HRTEM), Dynamic light scattering (DLS), X-ray diffraction (XRD) and EDX analysis showed the crystalline form of the AgNPs with Z-average size 57.25 nm. The zeta potential value of -25.7 mV demonstrated the negative surface charge and colloidal stability of AgNPs. The antimicrobial activity of AgNPs displayed effective inhibition zone against selected bacterial and fungal pathogens. In vitro, antioxidant effects were assessed by 1,1-diphenyl-2-picryl-hydrazyl (DPPH), hydrogen peroxide and reducing power assays which revealed excellent scavenging potential for AgNPs than the extracts. The anti-proliferative potential of biofabricated AgNPs and extracts on Human Non-small lung cancer cell line (A549) was assessed using 3–(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay with IC50 values of 15 µgmL-1 and 175 µgmL-1 respectively. Conclusion:The study reveals that the microalgae-mediated AgNPs possesses potent antimicrobial and antioxidant activity along with the ability to stimulate apoptosis in A-549 cell line.

Effect of Nature of Nonpolar Hydrocarbon Solvents on Adsorption Capacity of Synthetic Fatty Acids, Amines, and Amides

The sorption of surface-active substances (surfactants), namely, C18–C21 synthetic fatty carboxylic acids (distillation residues of their production), a number of amines, and amides from films of pure, normal paraffinic hydrocarbons such as heptane, octane, nonane, decane, and pentadecane deposited on St3 steel immersed in 0.5 M NaCl solution, has been studied. Concentrations have been obtained at which the degree of surface filling with surface-active substances approaches unity. It is shown that surfactant adsorption takes place on an energetically inhomogeneous surface, and it seems that in a number of cases it is realized by the donor-acceptor interaction mechanism.

Kinetics of the Hydrodeoxygenation of Ethyl Ester of Decanoic Acid over the Ni–Cu–Mo/Al2O3 Catalyst

The use of nickel-based catalysts in the hydrodeoxygenation of vegetable oils is an alternative to employing systems based on noble metals and sulfided hydrotreatment catalysts. Modifying nickel hydrodeoxygenation catalysts with molybdenum and copper increases the yield of target reaction products and the resistance of catalytic systems to the effect of an aggressive medium. The aim of this work is to determine the dependence between the temperature, contact time, and activity of modified nickel-containing catalyst in the hydrodeoxygenation of esters of fatty carboxylic acids and determine the effective kinetic parameters for the consumption of the reagent. The experiments are performed in a continuous flow reactor with a fixed catalyst bed at $${{P}_{{{{{\text{H}}}_{2}}}}}$$ = 0.25 MPa, temperatures of 270, 285, 300, and 315°C, and a contact time varying from 600 to 1800 s. The results show the selectivity toward the main reaction products (nonane and decane) remains the same when either the temperature of experiment or the contact time are varied. Experimental data are used to determine the effective rate constant and energy of activation of ester consumption.

Synthesis and Characterization of an Iron-Containing Fatty Acid-Based Ionomer

One of the desirable research goals today is to convert agro-based raw materials into low-cost functional polymers. Among the readily available natural raw materials are the fatty acids that can be obtained from the hydrolysis of plant oils or from the paper industry as byproducts. In this work, a novel iron-containing ionomer has been prepared through the reaction of fatty acids with steel dust or iron powder in the presence of carbon dioxide and water. Characterization has been achieved via 1H and 13C NMR, FT-IR, and size exclusion chromatography. The product has been shown to have an ionomeric structure, consisting of oligomers of fatty acid carboxylates (derived from Diels-Alder reaction) coupled with iron(II) and iron(III) ions (from the oxidation of iron). Because the fatty acid oligomers have low molecular weights, the ionomer easily dissolves in a solvent and can be made into different physical forms, such as liquid, solid, film, or foam.

Kinetic Studies of Hydrodeoxygenation of Ethyl Ester of Decane Acid over a Ni-Cu-Mo/Al2O3 Catalyst

Nickel-based catalysts for hydrodeoxygenation of vegetable oils are an alternative to the systems based on noble metals and sulfide catalysts for hydrotreatment. Modification of the nickel catalysts with molybdenum and copper allows the yield of target products to be increased and the corrosion resistance of the catalytic system to be improved. The studies were aimed at establishing relationships between temperature, contact time and activity of the modified nickel-containing catalyst to hydroxygenation of esters of fatty carboxylic acids, as well as at determining effective kinetic parameters of the reactant consumption. A flow reactor with the fixed catalyst bed was used for experimental studies at РН2 = 0.25 MPa, temperatures 270, 285, 300 and 315 °C, contact time varied from 600 to 1800 s. It was shown that the selectivity to the main reaction products – nonane and decane – did not change upon varying the reaction temperature and contact time. The experimental data were used for determining the effective rate constants and activation energy of the reaction.

Octanoic acid hydrodeoxygenation over bifunctional Ni/Al-SBA-15 catalysts

Hydroprocessing of fatty carboxylic acids over 5 wt% Ni/Al-SBA-15 reveals a strong dependence of product yield and selectivity on Si : Al ratio.

Synthesis and Investigation of Thermal Properties of Highly Pure Carboxylic Fatty Esters to Be Used as PCM

Latent heat storage systems are gaining the attention of researchers as possible substitutes to conventional sensible heat storage systems due to their compactness and their ability to absorb and release heat almost isothermally. Among the Phase Change Materials (PCM) for energy storage studied so far, esters are believed to show promising properties. In particular, a broad range of melting temperatures, little to no supercooling, low corrosivity, chemical and thermal stability, and high enthalpies of fusion are reported. Many esters have the advantage of being bio-based and biodegradable, making them more sustainable in comparison to other popular PCM. Still, a clear lack of experimental data exists in regards to this class. In the present study, esters derived from saturated fatty carboxylic acids (myristic, palmitic, stearic, behenic), coupled with primary linear alcohols of different length (methanol, 1-decanol) were synthesized through Fischer esterification and their properties were investigated. Purities higher than 89% were obtained for all cases as proven by gas chromatography coupled with mass spectroscopy and nuclear magnetic resonance analysis. Additionally, the esters’ formation and reaction kinetics were characterized by attenuated total reflectance infrared spectroscopy. The esters produced showed to possess relatively high enthalpies of fusion above 190 J/g and thermal stability over three repeated cycles with differential scanning calorimetry. The melting points measured ranged between 20 °C and 50 °C, therefore proving to be interesting candidates for low-medium temperature applications such as heating and cooling in buildings. A correlation could be observed between the chemical structure and melting point of the produced esters. Additionally, thermogravimetric analysis revealed a higher thermal resistance for esters with longer aliphatic chains in comparison to shorter-chained ones.

Characterisation of oil and aluminium complex on replica and historical 19th c. Turkey red textiles by non-destructive diffuse reflectance FTIR spectroscopy

This work investigates historical and replica Turkey red textiles with diffuse reflectance infrared (DRIFT) spectroscopy to study the coordination complex between cellulose, fatty acids, and the aluminium ions that form the basis of the colour lake. Turkey red was produced in Scotland for around 150 years, and is held in many museum and archive collections. The textile was renowned for its brilliant red hue, and for its fastness to light, washing, rubbing, and bleaching. This was attributed to its unusual preparatory process, the chemistry of which was never fully understood, that involved imbuing cotton with a solution of aqueous fatty acids and then aluminium in the following step. Here we show, for the first time, a characterisation of the Turkey red complex on replica and historical textiles. The development of techniques for non-destructive and in situ analysis of historical textiles is valuable for improving understanding of their chemistry, hopefully contributing to better conservation and display practices. The results show the fatty acids condense onto the cellulose polymer via hydrogen bonding between the CO and OH of the respective compounds, then the aluminium forms a bridging complex with the fatty acid carboxyl. This contributes to an improved understanding of Turkey red textiles, and shows the useful application of handheld diffuse FTIR instruments for heritage textile research.

Polymer Stabilized Catalysts Based on Platinum Group Metals for Synthesis of Higher Alcohols

The selective hydrogenation of the carboxyl group of fatty acids during synthesis of higher alcohols was studied in the presence of polymer stabilized catalysts based on noble metals. The studies were focused on the influence of the support and active metal on the yields of the target product and on the rate of substrate conversion. The highest yields, selectivity and the rates of stearyl alcohol accumulation were observed with catalysts 1%Pd/MN270, 1%Pt/MN500, 1%Ru/MN100. 1%Pd/MN270 and 1%Ru/MN100 catalysts were shown to retain their catalytic activities over at least five cycles of the multiple use, while 1%Pt/MN500 to lose it in the second cycle because of the catalyst thermal destruction during the reaction. The application of 1%Pd/MN270 for hydrogenation of carboxyl groups of stearic acid allows the yield of stearyl alcohol to be as high as 99 % at the 100 % conversion of the substrate.

Re-evaluation of sodium, potassium and calcium salts of fatty acids (E470a) and magnesium salts of fatty acids (E470b) as food additives.

The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re‐evaluating the safety of sodium, potassium and calcium salts of fatty acids (E 470a) and magnesium salts of fatty acids (E 470b) when used as food additives. In 1991, the Scientific Committee on Food (SCF) established a group acceptable daily intake (ADI) ‘not specified’ for the fatty acids (myristic‐, stearic‐, palmitic‐ and oleic acid) and their salts. The sodium, potassium, calcium and magnesium salts of fatty acids are expected to dissociate in the gastrointestinal tract to fatty acid carboxylates and their corresponding cations. There were no data on subchronic toxicity, chronic toxicity, reproductive and developmental toxicity of the salts of fatty acids. There was no concern for mutagenicity of calcium caprylate, potassium oleate and magnesium stearate. From a carcinogenicity study with sodium oleate, a no observed adverse effect level (NOAEL) could not be identified but the substance was considered not to present a carcinogenic potential. Palmitic‐ and stearic acid which are the main fatty acids in E 470a and E 470b were already considered of no safety concern in the re‐evaluation of the food additive E 570. The fatty acid moieties of E 470a and E 470b contributed maximally for 5% to the overall intake of saturated fatty acids from all dietary sources. Overall, the Panel concluded that there was no need for a numerical ADI and that the food additives sodium, potassium, calcium and magnesium salts of fatty acids (E 470a and E 470b) were of no safety concern at the reported uses and use levels.

Development of a GC/MS method for the qualitative and quantitative analysis of mixtures of free fatty acids and metal soaps in paint samples

In this paper we present a new analytical GC/MS method for the analysis of mixtures of free fatty acids and metal soaps in paint samples. This approach is based on the use of two different silylating agents: N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and 1,1,1,3,3,3-hexamethyldisilazane (HMDS).Our experimentation demonstrated that HMDS does not silylate fatty acid carboxylates, so it can be used for the selective derivatization and GC/MS quantitative analysis of free fatty acids. On the other hand BSTFA is able to silylate both free fatty acids and fatty acids carboxylates. The reaction conditions for the derivatization of carboxylates with BSTFA were thus optimized with a full factorial 32 experimental design using lead stearate and lead palmitate as model systems. The analytical method was validated following the ICH guidelines. The method allows the qualitative and quantitative analysis of fatty acid carboxylates of sodium, calcium, magnesium, aluminium, manganese, cobalt, copper, zinc, cadmium, and lead and of lead azelate. In order to exploit the performances of the new analytical method, samples collected from two reference paint layers, from a gilded 16th century marble sculpture, and from a paint tube belonging to the atelier of Edvard Munch, used in the last period of his life (1916–1944), were characterized.