Carboxylic Acid Compounds Research Articles

Antimicrobial Biphasic Polymer Coatings Enabled by Fast Diffusion of Active Compounds.

The recent COVID-19 pandemic and the prospect of future global pandemics highlight the long-standing need to passively eliminate viruses and bacteria on surfaces. Conventional antimicrobial surfaces and coatings are typically constrained by a trade-off between antimicrobial efficacy and physical durability. A biphasic polyurethane coating has been developed that breaks this trade-off by incorporating a durability-imparting polycarbonate (PC) discrete phase with a continuous poly(ethylene glycol) (PEG) transport phase that absorbs, stores, and releases antimicrobial active compounds for extended microbial inactivation. The biphasic polymer was shown to absorb carboxylic acid and quaternary ammonium antimicrobial active compounds, maintained their levels after five years of simulated cleaning, and inactivated up to 99.99% of Human Coronavirus 229E and Influenza A H1N1. Furthermore, the levels of antimicrobial active compounds on the biphasic coating could be augmented by cleaning the substrate with a disinfectant. The practicality of biphasic coatings for automotive and commercial aerospace environments was demonstrated by showing control of hardness and stain resistance through biphasic composition, showing environmental durability through heat, humidity, and light exposure, and passing flammability protocols.

Ren-Shen-Bu-Qi decoction alleviates exercise fatigue through activating PI3K/AKT/Nrf2 pathway in mice.

Fatigue is a prevalent issue that can lead individuals to a sub-health condition, impacting their work efficiency and quality of life. There are limited effective treatment options available for fatigue. Ren-Shen-Bu-Qi decoction (RSBQD) is a proprietary herbal remedy that is designed to address fatigue. However, the specific pharmacological mechanisms and basis of RSBQD are not yet fully understood. This study aimed to investigate the pharmacological effects and mechanisms of RSBQD in a mouse model of exercise fatigue. UPLC-Q-Orbitrap HRMS was used to analyze the chemical composition of RSBQD. The pharmacological basis and molecular mechanism of RSBQD on exercise fatigue were predicted using network pharmacology analysis. Subsequently, an exercise fatigue mouse model was established and used to analysis the effects of RSBQD. The potential mechanisms were verified by hematoxylin-eosin (HE) staining, real-time fluorescence quantitative PCR (RT-qPCR), Western blot (WB) and molecular docking. The results showed that 88 main components of RSBQD were identified, which have mainly belonged to flavonoids and carboxylic acid compounds. The network pharmacology analysis indicated that RSBQD ameliorate fatigue through PI3K/AKT signaling pathway. Notably, RSBQD prolonged the swimming time and diminished body weight loss of exercise fatigue mice (P < 0.05). Meanwhile, RSBQD significantly alleviated the injury of liver and kidney induced by exhaustive exercise, and decreasing the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea and BUN levels (P < 0.05). In addition, RSBQD was found could relieve exercise fatigue by decreasing the content of creatine kinase (CK), lactate dehydrogenase (LDH), and lactic acid (LA), but increasing the blood glucose (GLU) and liver glycogen (HG) levels (P < 0.05). RSBQD also significantly increased the hepatic superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) but decreased hepatic malondialdehyde (MDA) levels. Moreover, RSBQD was able to upregulate protein level of activated Nrf2 and PI3K/AKT signaling pathways. RSBQD mitigates exercise fatigue by reversing metabolic changes and reducing oxidative damage through the PI3K/AKT/Nrf2 signaling pathway. This study offers pharmacological support for the utilization of RSBQD in exercise fatigue treatment.

Molecular docking study of modified isoniazid compounds on mycolic acid synthase in the cell wall of mycobacterium tuberculosis

Using the isoniazid in antituberculosis therapy can lead to mutations in the KatG and inhA genes of Mycobacterium tuberculosis, resulting in the development of resistance and necessitating modifications to the isoniazid compound. This study aims to assess the potential and level of toxicity of modified compounds, namely 4-pyridine carboxylic acid, pyridine aldehyde, and methyl pyridine, on the mycolic acid receptor through a molecular docking approach. PyRx was employed for the docking process using a protocol with an exhaustiveness of 106 and a center grid box at X=42.424, Y=22.4321, and Z=46.6391. Additionally, the ProTox-II website was used to determine the toxicity level of the test compounds. The results obtained from this research consist of the respective affinity values of the test compounds: -6, -5.4, and -5.2 kcal/mol. The toxicity levels of the test compounds are as follows: class 5, class 4, and class 4. All test compounds interact with amino acids on the target protein, specifically with residue numbers Histidine (HIS A:8), Phenylalanine (PHE A:142) through hydrogen bonding, Leucine (LEU A:95) through pi-Sigma (π) bonding, and Valine (VAL A:12) through pi-Alkyl (π) bonding. In conclusion, the 4-pyridine carboxylic acid compound exhibits potential as a promising drug candidate but comes with a high level of toxicity

High-Efficiency Photocatalytic Oxidation of Benzyl Alcohol by NH2-UiO-66-(Indole-2,3-Dione)-Fe.

The photocatalytic oxidation of biomass-derived benzyl alcohol provides a promising way for the synthesis of benzoic acid, which is an important intermediate with wide applications. To improve the efficiency of photocatalytic benzyl alcohol oxidation to benzoic acid is of great interest. In this work, we propose the utilization of NH2-UiO-66-ID-Fe catalyst for photocatalytic oxidation of benzyl alcohol to benzoic acid, where NH2-UiO-66 is a typically used metal-organic framework, ID is indole-2,3-dione (ID) that has biocompatibility, light absorption property and can be covalently combined with amino-functionalized substances. The NH2-UiO-66-ID-Fe catalyst exhibits improved light absorption and photo-generated electron-hole separation ability compared with NH2-UiO-66. The photocatalytic performance of NH2-UiO-66-ID-Fe was examined for the oxidation of bio-based benzyl alcohol under mild conditions of air atmosphere, room temperature and no additive or additional oxidant involved. The results show that the conversion of benzyl alcohol and the selectivity to benzoic acid could both reach over 99 % in 6 h, and the generation rate of benzoic acid per gram of catalyst is 3.36 mmol g-1 h-1. The reaction mechanism was detected by radical trapping method and in situ electron paramagnetic resonance. This study presents an efficient and environmentally benign avenue for the synthesis of carboxylic acid compounds.

Highly selective oxidation of glucose to formic acid and exploring reaction pathways using continuous flow microreactors

The process of converting glucose into formic acid (FA) has been explored as a promising route for using biomass as a renewable feedstock for green chemical manufacturing. However, the most commonly used batch-tank reactor systems currently suffer from several drawbacks, including extended processing time, limited product selectivity, and high energy consumption, while the underlying reaction paths have been poorly understood. In this work, a continuous flow microchannel reactor was employed for the glucose conversion catalyzed by H5PV2Mo10O40 with O2 as an oxidant. The influence of various parameters on the conversion rate of glucose and the FA yield was characterized. Experimental results indicated that with a residence time of less than 3 min, the glucose was completely converted, and the highest FA yield reached 82.40 %. Extensive examination on the apparent by-products revealed that most of them acted as intermediates to produce FA through various pathways, including glyoxal, glyceraldehyde and glycolaldehyde as key intermediates for the oxidation of glucose to FA. Furthermore, the density functional theory (DFT) method was used to determine the bond energies of different C–C bond cleavage modes of substrate glucose and fructose produced by the isomerization of glucose. Experimentally, the conversion of three main intermediates and some other possible intermediates and their FA yield were measured with different residence time. It was also found that the CO2 was produced through the decarboxylation of α-hydroxy and α-carbonyl carboxylic acid compounds, while the aldehyde groups in the compounds were more likely converted to FA by the α-carbon bond cleavage. Finally, plausible reaction pathways were proposed for the process of glucose-to-FA catalyzed by HPA-2, providing useful guidance for the identification of side reaction pathways and further improvement of FA yield.

Effects of varied exercise intensities on growth, muscle quality and volatile compounds in largemouth bass (Micropterus salmoides) cultured in recirculating aquaculture system

To explore the impact of different exercise intensities on the growth, muscle quality, and volatile compounds of largemouth bass, this study involved 270 fish with an initial weight of 96.05 ± 18.87 g. They were divided into three groups: a control group (CG) exposed to a constant current speed of 0.30 cm/s for 24 h/day; an interval exercise group (IE) exercising at a rate of 2 body lengths per second (bl/s) for 8 h/day; and a sustained exercise group (SE) exercising continuously at 2 bl/s for 24 h/day. The experiment was conducted in a recirculating aquaculture system over a period of 90 days. Results revealed that SE exhibited remarkably greater body mass and condition factor (CF), with higher weight gain rate (WGR) and specific growth rate (SGR) compared to IE and CG (P < 0.05). SE exhibits superior growth performance. No significant differences was observed among the three groups in terms of centrifugal loss, drip loss, liquid loss, stored loss, and cooked rate. However, in terms of frozen leakage, the IE was considerably lower than the CG and SE (P < 0.05).In terms of raw meat texture, the hardness, chewiness, and shearing of the SE were notably greater than the CG (P < 0.05), and the SE were superior in hardness compared to the IE (P < 0.05). Regarding cooked meat texture, the SE exhibited significantly superior hardness, chewiness, springiness, and shearing compared to both the CG and IE (P < 0.05). The IE demonstrated higher levels of chewiness, springiness, and shearing compared to the CG (P < 0.05). With respect to nutritional indicators, the crude protein content of both the SE and IE was significantly higher than that of the CG. In terms of volatile substances, the CG had relatively high levels of carboxylic acid compounds and alcohol compounds in this experiment. The ketone compounds in the IE were significantly higher than those in the CG and SE. 2-Methylbutanoic acid methyl ester had the highest content in the SE. The results show that interval swimming exercise training and sustained exercise training can effectively improve the sensory quality of fish muscle, effectively remove the irritating smell in the muscle, and produce aromatic odor. Consequently, exercise training at varying intensities has been demonstrated to significantly enhance the growth and muscle quality of largemouth bass, offering potential strategies for improving fish product quality in the aquaculture industry. This contributes to increased efficiency and sustainability in fish farming practices and provides valuable insights for regulating the nutritional quality of fish muscle in future recirculating aquaculture system models.

GC-MS analysis of ethanolic extract of propolis from Jhajjar district in Haryana, India

Aim: To analyse the chemical composition of ethanolic extract of propolis, a glue like resinous natural material collected by worker honey bees from Jhajjar district of Haryana. Methodology: Chemical composition analysis of the ethanolic extract of propolis sample collected from Jhajjar district of Haryana, India was determined by Gas chromatography–mass spectrometry. Propolis sample was crushed to powdered form and extracted using 70% ethanol and kept for around 20 days. The supernatant was then filtered and thereafter, the filtered extract was dried and collected in a clean vial. Results: GC-MS analysis revealed the presence of hydrocarbons, sugars, fatty acids, carboxylic acid, alcohols, ethers, carbamate ester and other organic compounds. Interpretation: The results revealed the presence of diverse biochemical constituents which can be utilized in therapeutics of several ailments to enhance the quality of life by improving human health. Key words: Chemical profile, Fatty acids, Organic compounds, Propolis

Fabrication of molecularly imprinted carbon nanotubes integrating ionic liquids for efficient detection of perfluoroalkyl carboxylic acid in environmental water

It is extremely significant while challenging to accurately detect low-levels of perfluoroalkyl carboxylic acid compounds (PFCAs) in environmental water. Herein, adopting perfluorotetradecanoic acid as the dummy template, selective molecularly imprinted composites (CNTs@ILs@MIPs) grafted carbon nanotubes integrating hydrophilic ionic liquids were successfully prepared via surface imprinting and dummy-template imprinting techniques. The obtained CNTs@ILs@MIPs were applied as selective extraction adsorbent for specifically extract PFCAs in environmental water coupled with gas chromatography-mass spectrometry quantification. Detailed studies were conducted on the main preparation parameters and extraction conditions. The CNTs@ILs@MIPs displayed excellent adsorptivity, and the established method exhibited low LODs (0.60–1.64 ng L−1), wide linearity with R2 above 0.9994, and satisfactory adsorption recoveries (80.5–112.5%) for seven PFCAs. This proposed method provides a new applicable approach for the detection of targeted pollutants in environmental water by utilizing the high affinity and recognition ability of molecularly imprinted carbon nanotube functional materials modified with ionic liquids.

Genome analysis of a newly isolated Bacillus velezensis-YW01 for biodegrading acetaldehyde.

Acetaldehyde (AL), a primary carcinogen, not only pollutes the environment, but also endangers human health after drinking alcohol. Here a promising bacterial strain was successfully isolated from a white wine cellar pool in the province of Shandong, China, and identified as Bacillus velezensis-YW01 with 16S rDNA sequence. Using AL as sole carbon source, initial AL of 1g/L could be completely biodegraded by YW01 within 84h and the cell-free extracts of YW01 has also been detected to biodegrade the AL, which indicate that YW01 is a high-potential strain for the biodegradation of AL. The optimal culture conditions and the biodegradation of AL of YW01 are at pH 7.0 and 38°C, respectively. To further analyze the biodegradation mechanism of AL, the whole genome of YW01 was sequenced. Genes ORF1040, ORF1814 and ORF0127 were revealed in KEGG, which encode for acetaldehyde dehydrogenase. Furthermore, ORF0881 and ORF052 encode for ethanol dehydrogenase. This work provides valuable information for exploring metabolic pathway of converting ethanol to AL and subsequently converting AL to carboxylic acid compounds, which opened up potential pathways for the development of microbial catalyst against AL.

Genetic and chemical control of tuberculostearic acid production in Mycobacterium avium subspecies paratuberculosis.

Tuberculostearic acid (TBSA) is a fatty acid unique to mycobacteria and some corynebacteria and has been studied due to its diagnostic value, biofuel properties, and role in membrane dynamics. In this study, we demonstrate that TBSA production can be abrogated either by addition of pivalic acid to mycobacterial growth cultures or by a bfaA gene knockout encoding a flavin adenine dinucleotide (FAD)-binding oxidoreductase. Mycobacterium avium subspecies paratuberculosis (Map) growth and TBSA production were inhibited in 0.5-mg/mL pivalic acid-supplemented cultures, but higher concentrations were needed to have a similar effect in other mycobacteria, including Mycobacterium smegmatis. While Map C-type strains, isolated from cattle and other ruminants, will produce TBSA in the absence of pivalic acid, the S-type Map strains, typically isolated from sheep, do not produce TBSA in any condition. A SAM-dependent methyltransferase encoded by bfaB and FAD-binding oxidoreductase are both required in the two-step biosynthesis of TBSA. However, S-type strains contain a single-nucleotide polymorphism in the bfaA gene, rendering the oxidoreductase enzyme vestigial. This results in the production of an intermediate, termed 10-methylene stearate, which is detected only in S-type strains. Fatty acid methyl ester analysis of a C-type Map bfaA knockout revealed the loss of TBSA production, but the intermediate was present, similar to the S-type strains. Collectively, these results demonstrate the subtle biochemical differences between two primary genetic lineages of Map and other mycobacteria as well as explain the resulting phenotype at the genetic level. These data also suggest that TBSA should not be used as a diagnostic marker for Map.IMPORTANCEBranched-chain fatty acids are a predominant cell wall component among species belonging to the Mycobacterium genus. One of these is TBSA, which is a long-chain middle-branched fatty acid used as a diagnostic marker for Mycobacterium tuberculosis. This fatty acid is also an excellent biolubricant. Control of its production is important for industrial purposes as well as understanding the biology of mycobacteria. In this study, we discovered that a carboxylic acid compound termed pivalic acid inhibits TBSA production in mycobacteria. Furthermore, Map strains from two separate genetic lineages (C-type and S-type) showed differential production of TBSA. Cattle-type strains of Mycobacterium avium subspecies paratuberculosis produce TBSA, while the sheep-type strains do not. This important phenotypic difference is attributed to a single-nucleotide deletion in sheep-type strains of Map. This work sheds further light on the mechanism used by mycobacteria to produce tuberculostearic acid.

Solanum aculeastrum Dunal berries: Phytochemical profiling and GC-MS analysis of methanolic extract and n-hexane, dichloromethane, ethyl acetate and n-butanol fractions

Background: Solanum aculeastrum is reportedly used in several diseases including gonorrhea, bronchitis, jigger infestations and wounds, and cancers. We conducted an exhaustive phytochemical and GC-MS profiling of its methanol extract and solvents’ fractions. Methods: About 4500g of dried berries of S. aculeastrum was extracted with methanol, part of which was partitioned into fractions of n-hexane, dichloromethane, ethyl acetate, n-butanol and aqueous fractions. These fractional preparations were subjected to phytochemical and GC-MS profiling except aqueous fraction. Results: The percentage yield of 430.69g of methanol extract of berries of S.aculeastrum was 9.57%w/w, while the yields of dried 19.4g of n-hexane, 38.4g of DCM, 6.4g of ethyl acetate, 81.03g of n-butanol and 21.2g of the freeze-dried aqueous fractions were 7.08%w/w, 14.03 %w/w, 2.33%w/w, 29.60%w/w and 7.74%w/w respectively. The relative presence of glycosides, alkaloids, tannins, flavonoids, terpenoids, phenols, saponins were confirmed except quinones. GC-MS profiling of methanol extract identified 32 compounds including alkane, alcohol, carbohydrate, fatty acids, terpenoids, glycerides, vitamins and some unclassified compounds. 25 compounds including terpenoids, alkene, fatty acids, vitamin and unclassified compounds were identified in n-hexane fractions. The DCM fraction yielded 20 compounds including isoprenoid, terpenoids, amino acids, carboxylic acid and unclassified compounds. 22 compounds were identified in ethyl acetate fraction including phenol, fatty acids, alcohol, terpenoids, glycerolipid and unclassified compounds. The n-butanol fraction yielded 11 compounds including fluorinated aromatic substance, hormonal antineoplastic and a non-steroidal anti-inflammatory agent. Conclusion: This study has further elaborated on the bioactive compounds in berries of S. aculeastrum, to aid robust understanding of its pharmacologic activities.

Effect of Functional Groups in Lipid Molecules on the Stability of Nanostructured Lipid Carriers: Experimental and Computational Investigations.

Lipid nanoparticles have been used as drug carriers for decades. Many lipid types have been screened for both solid lipid nanoparticles and nanostructured lipid carriers (NLCs). Specifically, for NLCs that are composed of lipids in the solid form mixed with lipids in the liquid form, compatibility of lipid combination and phase behavior play a significant role in the NLC quality. In this study, stearic acid (STA) and cetyl palmitate (CTP) were used as solid lipids, and oleic acid (OLA), isopropyl palmitate (IPP), and caprylic/capric triglycerides were used as liquid lipids. NLCs were prepared at solid:liquid ratios of 50:50, 70:30, and 90:10, respectively. The characteristics and stability of the prepared NLCs were investigated. Laboratory results showed that the solid lipid had a greater influence on the particle size than the liquid lipid. Meanwhile, cetyl palmitate, an ester compound, provides higher NLC stability compared to stearic acid, a carboxylic acid compound. A MARTINI-based coarse-grained molecular dynamics simulation was used to simulate the lipid droplet in water. The distribution of lipid molecules in the droplet was characterized by the polar group density distribution. Different spatial arrangements of the lipid headgroup and lipid molecules, when CTP or STA was used as solid lipids, might contribute to the different stabilities of prepared NLCs. The understanding of mixed lipid systems via simulations will be a significant tool for screening the type of lipids for drug carriers and other pharmaceutical applications.

Deacetylation of Mannosylerythritol Lipids in Hydrophobic Natural Deep Eutectic Solvents

AbstractMannosylerythritol lipids (MELs) are a promising group of biosurfactants due to their high fermentation yield, selfassembly and biological activity. During fermentation by Pseudozyma aphidis, a mixture of MELs with different levels of acylation is formed, of which the fully deacetylated form is the most valuable. In order to reduce the environmental impact of deacetylation, an enzymatic process using natural deep eutectic solvents (NADES) has been developed. We tested the deacetylation of a purified MELs mixture with immobilized Candida antarctica lipase B enzyme and 2‐ethylhexanol as co‐substrate in 140 h reactions with different NADES. We identified hydrophobic NADES systems with similar yields and kinetics as in pure 2‐ethylhexanol solvent. Our results indicate that deacetylation of MELs mixtures in NADES as a solvent is possible with yields comparable to pure co‐substrate and that hydrophobic NADES without carboxylic acid compounds facilitate the reaction to the greatest extent.

Zinc nanoparticles mediated by Costus pictus leaf extract to study GC-MS and FTIR analysis

Plants have been used to treat illnesses from the dawn of time, and the term “medicinal plants” has taken on special significance. Because of their pharmacological potency, these plants have continued to be used as a source of medicines and other natural goods worldwide. Costus pictus, Commonly known as flaming costus (Costus igneus Nak), is a South-central American plant recently brought to India. It belongs to the Costaceae family. It is called the “insulin plant” in India because of its alleged anti-diabetic qualities. The methods utilized in this study are GC-MS, FTIR and SEM analysis. The results revealed that GC-MS shows the presence of different compounds: fatty acids, terpenoids, Alkanes, Carboxylic acid and aromatic compounds. The FTIR analysis depicts various functional groups comprising alkanes, alkenes, alkynes, carboxylic acid, aromatic compounds, and halo compounds. SEM analysis depicts the shape and size of nanoparticles, and the size of nanoparticles is 77nm – 113nm. Further research should be done on the characterization of Zn nanoparticles, metabolomics analysis and pharmacological activities.

Improved phenol degradation by catalytic wet air oxidation on the Co3O4 spinel catalysts supported on SBA-15 modified with TiO2

The removal of phenol from aqueous industrial effluents by catalytic wet-air oxidation (CWAO) is a challenging process that requires novel catalysts resistant to leaching of the active phases during residence time in a batch reactor. In this sense, this work demonstrated that this can be archived with the catalyst having the spinel phase Co3O4 supported on mesoporous silica SBA-15 doped with an optimized amount of TiO2 (3 wt%). In the phenol CWAO reaction carried out at 160 °C and 10 bar O2, this best Co3O4/TiO2/SBA-15 catalyst showed an increase of phenol conversion from 49.0 % to 68.3 % and of CO2 selectivity from 87 % to 98 %. The extensive catalyst characterization and overall activity results indicated that this was related to the strength and nature of the acid sites and the oxidation states of the cobalt oxide phases. Combined factors influenced the final behaviour of the catalyst, such as its intrinsic activity, dispersion of the active phase, inhibition of CoSiO4 phase formation, high Lewis acidity and the large amount of active Co3O4 spinel phase. The presence of TiO2 nanoparticles (NPs) decorating the support surface improved the stability of the catalyst by inhibiting the leaching of cobalt species during the reaction. After three reaction cycles, the most efficient Co/3Ti/S15 catalyst showed high CO2 selectivity (∼92.7 %) and low selectivity towards carboxylic acid (∼5.3 %) and polyphenolic compounds (∼2%). It is proposed that surface oxidation is the rate-determining step in the CWAO reaction over TiO2/SBA-15-supported Co3O4 spinel catalysts.

EFFECT OF ETHANOL-WATER CONCENTRATION AS EXTRACTION SOLVENT ON ANTIOXIDANT ACTIVITY OF Acalypha indica

Acalypha indica is an abundant and obtainable wild weed plant in Indonesia. This is a possible opportunity to enhance its utility. The effect of free radicals is one of the factors that contribute to oxidative stress in the body, which can lead to cell damage and trigger various diseases. Plants rich in antioxidants can inhibit free radical reactions and protect the body from oxidative stress. In this study, we conducted the identification of major metabolite compounds using UHPLC-Q-Orbitrap HRMS from 70% ethanol extracts of Acalypha indica. We also performed phytochemical and antioxidant activity tests with various concentrations of ethanol-water solvents including water, 30%, 50%, 70% ethanol, and absolute ethanol to determine the optimal extraction conditions and the influence of solvent concentration on the antioxidant activity of Acalypha indica extract. The results of UHPLC-Q-Orbitrap HRMS identification showed that the 70% ethanol extract of Acalypha indica contains 10 major compounds suspected to correlate with its antioxidant activity. These include five flavonoids compounds (palasitrin, vitexin 2"-o-p-coumarate, isorhamnetin 3- (3",6"-di-p-coumarylglucoside), peucenin, and sulfuretin), two amino acid compounds (2-amino-3-carboxymuconic acid semialdehyde and N-Acetyl-L-phenylalanine), two carboxylic acid compound (citric acid and traumatic acid), and one phenolic compound (quinic acid). Phytochemical tests show positive results for flavonoids, tannins, alkaloids, and triterpenoids in each of water, 30%, 50%, 70% ethanol, and absolute ethanol extracts. The best antioxidant activity was obtained from the 70% ethanol extract with an IC50 value of 47.064 ppm, categorizing it as an extremely strong antioxidant.

A novel application of CO2 corrosion inhibitory potentials of banana peel extract on mild steel: Experimental studies

The corrosion inhibitory effect of banana peel extract on mild steel in a CO2 corrosion environment is studied using weight loss method. The corrosion mechanism is studied with respect to process parameters such as the concentration of the extract, pH, temperature, and immersion time. The extract production is done using maceration method, while FTIR analysis is used to confirm the constituents of the chemical functional groups. The morphology of the corroded coupons’ surface examines SEM microscopy. The results show that the respective corrosion rate increase of 0.184–0.347 mgcm−2h−1 and 0.128–0.354 mgcm−2h−1 are obtained when temperature and immersion time increased from 35 to 75 °C and 48 to 240 h, respectively. Also, a decrease in corrosion rate of 1.01–0.128 mgcm−2h−1 and 0.035–0.0 is noted when the concentration and pH increased from 0.0001 to 1.0 g/l and 3–12, respectively. Changes in these respective experimental parameters yielding corrosion inhibitory efficiencies of (98.0–95.1), (99.1–96.0), (96.1–98.0) and (99.1–100) %. FTIR analysis confirmed the presence of electron copious functional groups such as alkane, amine, alcohol, carboxylic acid, ester and nitro compound that contain O2 and N2 atoms that can donate lone pair electrons and bind metal ions. The SEM micrographs indicated that more severity of the corrosion effects is associated with low pH and high temperature conditions. That is in good agreement with corrosion test results. Hence, a strong correlation is established between the process conditions and the corrosion mechanism. It therefore concludes that banana peel has potential for CO2 corrosion mitigation.

Differential Impact of Zinc Salt Precursors on Physiognomies, Anticancerous, and Antibacterial Activities of Zinc Oxide Nanoparticles.

Zinc oxide nanoparticles (ZnONPs) are enormously popular semi-conductor metal oxides with diverse applications in every field of science. Many physical and chemical methods applied for the synthesis of ZnONPs are being rejected due to their environmental hazards. Therefore, ZnONPs synthesized from plant extracts are steered as eco-friendly showing more biocompatibility and biodegradability. Additionally, various synthesis conditions such as the type of precursor salt also play a role in influencing the physicochemical and biological properties of ZnONPs. In this study, green synthesis of ZnONPs from Acacia nilotica was carried out using zinc acetate (ZA-AN-ZNPs), zinc nitrate (ZN-AN-ZNPs), and zinc sulfate (ZS-AN-ZNPs) precursor salts. Surprisingly, characterization of ZnONPs using UV-visible spectroscopy, TEM, XRD, and EDX revealed the important role precursor salts played in influencing the size and shape of ZnONPs, i.e., 20-23nm spherical (ZA-AN-ZNPs), 55-59nm triangular (ZN-AN-ZNPs), and 94-97nm nano-flowers (ZS-AN-ZNPs). FTIR analysis showed the involvement of alkaloids, alcohols, carboxylic acid, and phenolic compounds present in Acacia nilotica extract during the synthesis process. Since different precursor salts showed different morphology of ZnONPs, their biological activities were also variable. ZN-AN-ZNPs showed the highest cytotoxicity towards HepG2 cells with the lowest cell viability (28.92 ± 0.99%), highest ROS/RNS production (3425.3 ± 184.58 relative DHR123 fluorescence), and loss of mitochondrial membrane potential (1645.2 ± 32.12 relative fluorescence unit) as well as induced significant caspase-3 gene expression. In addition to this, studying the zone of inhibitions and minimum bactericidal and inhibitory concentrations of ZnONPs showed their exceptional potential as antibacterial agents. At MIC as low as 8µg/mL, ZA-AN-ZNPs and ZN-AN-ZNPs exhibited significant bactericidal activities against human pathogens Klebsiella pneumoniae and Listeria monocytogenes, respectively. Furthermore, alkaline phosphatase, DNA/RNA leakage, and phosphate ion leakage studies revealed that a damage to the bacterial cell membrane and cell wall is involved in mediating the antibacterial effects of ZnONPs.

Hydrophobic coating using sustainable sol-gel process doped with carboxylic acids to protect heritage copper artefacts

Metal corrosion and its mitigation using alkoxysilane based sol-gel coatings presenting specific properties are a matter of interest in many areas of applications, from industrial to cultural heritage materials. Thanks to their adhesive and coupling nature with different molecules and substrates, they show excellent results against aggressive environments. This study focuses on the protection of historical copper-based alloys. A tetramethyl orthosilicate-based (TMOS-based) sol-gel coating was doped with carboxylic acid compounds (heptanoic, octanoic and decanoic acids) recognized for their non-toxicity and their interesting corrosion inhibition properties on ancient corroded copper. The development of the coating and the basic understanding of the fundamental chemistry as well as the protection mechanism on the historical samples were studied. Contact angle measurements allowed to show that the resulting coating displayed a hydrophobic protection at the surface of the samples while its chemical composition was evaluated using thermogravimetric analysis, SEM-EDS and Raman spectroscopy. The porosity of the sol-gel matrix and the distribution of the acids in the porous silica network were then investigated by establishing nitrogen adsorption/desorption isotherms at liquid N2 temperature. Examination of the sample's cross-section by SEM-EDS showed that the TMOS-based coatings doped with carboxylic acids penetrated up to 60 % in depth in the corrosion layer of the ancient copper, while the Raman analyses showed that the acids formed organometallic complexes both at the surface and in the corrosion layer, leading to the protection of the metallic substrate against further corrosion.

Selective electrocatalytic oxidation of C(OH)–C bond in lignin with Pt@CeO2 toward the synthesis of benzoic acid

The synthesis of carboxylic acid compounds by the selective electrooxidation cleavage of the C(OH)-C bond in lignin is significant to biomass conversion to produce high-value-added chemicals. However, it is challenging to selectively cleave the C(OH)-C bond due to its extremely high dissociation energy of 260–300 kJ mol−1. Herein, a simple and effective method of hydrothermal process and wet impregnation is proposed to synthesize Pt@CeO2 catalysts. The cleavage of the C(OH)-C bond by Pt@CeO2, a catalyst loaded with a small amount of noble metal, triggered the electrochemical oxidation of lignin, resulting in the highly selective synthesis of carboxylic acid compounds. Consequently, more reactive oxygen species (ROS) are produced in the electrocatalytic oxidation process, which enhances the cleavage of C(OH)-C bond and the oxidation of benzaldehyde. In addition, Pt@CeO2 can also be used for the electrochemical depolymerization of industrial alkali lignin to produce carboxylic acids. This research proposes an efficient way of producing carboxylic acids of high value by utilizing an electrocatalyst for the electrocatalytic oxidation of lignin.