Phenolic Aldehyde Research Articles

Using the Groundwater Cooling System and Phenolic Aldehyde Isolation Layer on Building Walls to Evaluation of Heat Effect

This study examines the thermal performance of building walls under full sunlight conditions using various insulation strategies. Specifically, it evaluates: (1) the effects of heat on building walls and indoor spaces; (2) the impact of groundwater cooling systems on thermal environments; (3) the influence of phenolic aldehyde insulation layers on heat transfer; and (4) the combined effects of groundwater cooling and phenolic aldehyde thermal insulation. Fluent–CFD (Computational Fluid Dynamics) was used in the study to simulate temperature transmission between the sun, the groundwater cooling system, and both indoor and outdoor spaces. Experimental analysis and simulations reveal that both the phenolic aldehyde insulation layer and the groundwater cooling system effectively reduce heat transfer, with the groundwater cooling system demonstrating the most significant impact. The phenolic aldehyde layer decreases the temperature difference between inner and outer walls by approximately 8 °C. The groundwater cooling system further reduces both inner and outer wall temperatures, helping to maintain cooler indoor environments. Simulation results indicate that, while the phenolic aldehyde layer effectively prevents external heat from penetrating into the room, it does not eliminate heat accumulation. In contrast, the groundwater cooling system efficiently dissipates heat, mitigating this issue. Groundwater analysis shows that maximum temperature differences occur at specific times of the day, with water flow effectively cooling the space. The combined use of the phenolic aldehyde insulation layer and the groundwater cooling system offers superior thermal performance. The phenolic layer provides effective heat blocking, while the groundwater system facilitates heat dissipation, optimizing indoor temperature and reducing air conditioning loads. This combination enhances overall comfort and energy efficiency, with the groundwater cooling system benefiting from reduced flow velocity and lower energy consumption.

Comparative study on the characterization of chitosan mixed natural phenolic aldehyde edible films

Comparative study on the characterization of chitosan mixed natural phenolic aldehyde edible films

A novel method for ultra-fast determination of phenolics with performance comparable to UPLC/DAD: Method development and validation on analysis of seedless table grapes

Grapes are well-known for the rich content of phenolics with benefits for human health. The reliable identification of phenolics in grapes is essential to explore the related bioactivity, highlighting the value of the grape source. In this work, an ultra-fast method for determining phenolic compounds in HPLC-DAD using a Rapid Resolution High Throughput-RRHT column (RP-C18 4.6 ×50 mm, 1.8 µm) was developed and validated and nine seedless table grapes produced in the São Francisco Valley, Brazil were analyzed. The method showed good sensitivity (LOD≤ 0.65 mg/L and LOQ< 1.12 mg/L), high linearity (R2 > 0.998), selectivity, precision (CV%< 6.82). The recovery (81.5–105.6 %) was adequate for the desired purpose. A total of 41 phenolics were separated in 20 min, rending a resolution equivalent to UPLC-DAD. Thirty-four phenolics were quantified in grapes, including eight phenolic acids, two stilbenes, one phenolic aldehyde, three isoflavones, four flavanols, three proanthocyanidins, five flavonols, and eight anthocyanins. Patented grapes presented a high content of mono glucoside anthocyanins. Brazilian registered grapes presented high anthocyanin content and the presence of 3,5-diglucoside anthocyanins. The validated method is an alternative for rapid identification of phenolics and maybe useful to stablish procedures for identifying compounds in determining the markers in fruit.

Ascorbate peroxidase catalyses synthesis of protocatechualdehyde from p-hydroxybenzaldehyde in Lycoris aurea

Protocatechualdehyde is a plant natural phenolic aldehyde and an active ingredient with important bioactivities in traditional Chinese medicine. Protocatechualdehyde is also a key intermediate in the synthesis of Amaryllidaceae alkaloids for supplying the C6-C1 skeleton. However, the biosynthesis of protocatechualdehyde in plants remains obscure. In this study, we measured the protocatechualdehyde contents in the root, bulb, scape and flower of the Amaryllidaceae plant Lycoris aurea (L’Hér.) Herb., and performed the correlation analysis between the protocatechualdehyde contents and the transcriptional levels of the phenolic oxidization candidate protein encoding genes. We found that a novel ascorbate peroxidase encoded by the contig_24999 in the L. aurea transcriptome database had potential role in the biosynthesis of protocatechualdehyde. The LauAPX_24999 gene was then cloned from the cDNA of the scape of L. aurea. The transient expression of LauAPX_24999 protein in Arabidopsis protoplasts demonstrated that LauAPX_24999 protein was localized in the cytoplasm, thus belonging to Class II L-ascorbate peroxidase. Subsequently, LauAPX_24999 protein was heterogenously expressed in Escherichia coli, and identified that LauAPX_24999 biosynthesized protocatechualdehyde from p-hydroxybenzaldehyde using L-ascorbic acid as the electron donor. The protein structure modelling and molecular docking indicated that p-hydroxybenzaldehyde could access to the active pocket of LauAPX_24999 protein, and reside at the δ-edge of the heme group while L-ascorbic acid binds at the γ-heme edge. To our knowledge, LauAPX_24999 is the first enzyme discovered in plants able to biosynthesize protocatechualdehyde from p-hydroxybenzaldehyde, and offers a competent enzyme resource for the biosynthesis of Amaryllidaceae alkaloids via synthetic biology.

Development of Syringaldehyde as an Agonist of the GLP-1 Receptor to Alleviate Diabetic Disorders in Animal Models.

The phenolic aldehyde syringaldehyde (SA) has been shown to have an antihyperglycemic effect in diabetic rats due to increased glucose utilization and insulin sensitivity. To understand the direct effect of SA on the GLP-1 receptor, STZ-induced diabetic rats were used. The levels of pro-inflammatory cytokines, liver enzymes, and renal function were measured using specific ELISA kits. The mechanisms of SA effects were investigated using CHO-K1 cells, pancreatic Min-6 cells, and cardiomyocyte H9c2 cells. The results indicated that the antihyperglycemic effect of SA in diabetic rats was abolished by blocking the GLP-1 receptor with an antagonist. SA has a direct effect on the GLP-1 receptor when using CHO-K1 cells transfected with the exogenous GLP-1 receptor gene. In addition, SA stimulated insulin production in Min-6 cells by activating GLP-1 receptors. SA caused a dose-dependent rise in GLP-1 receptor mRNA levels in cardiac H9c2 cells. These in vitro results support the notion that SA has a direct effect on the GLP-1 receptor. Otherwise, SA inhibited the increase of pro-inflammatory cytokines, including interleukins and tumor TNF-α, in type 1 diabetic rats in a dose-dependent manner. Moreover, as with liraglutide, SA reduced plasma lipid profiles, including total cholesterol and triglyceride, in mixed diet-induced type 2 diabetic rats. Intriguingly, chronic treatment with SA (as with liraglutide) reversed the functions of both the liver and the kidney in these diabetic rats. SA displayed less efficiency in reducing body weight and food consumption compared to liraglutide. In conclusion, SA effectively activates GLP-1 receptors, resulting in a reduction in diabetic-related complications in rats. Therefore, it is beneficial to develop SA as a chemical agonist for clinical applications in the future.

Machine learning unveils the action of different endogenous phenolic compounds present or formed along the rooting development in olive stem cuttings

Changes in the endogenous phenolic content of plant rooting could be influenced by genotype, hormones, or the interaction of both factors, thus modifying the plant rooting capacity/ability along the rooting development. In this study, the combined effects of IBA treatment and cultivar capacity on the rooting development of olive cuttings were modeled by the temporary assessment of simple and total phenolic content (TPC). Rooting ability and phenolic profile were monitored. Results indicated the lowest cumulative rooting in `Lechin-de-Sevilla´, and the highest rooting speed during the first days of the trial in high-rooting cultivars (‘Verdial-de-Huévar’ and ‘Arbequina’). A total of 14 phenolic compounds comprising phenolic acids and aldehyde (8), flavonoids (5), and a glycosylated seco-iridoid were quantified in rooted olive cuttings. Most of the phenolics presented a significant higher concentration in the ‘Lechin-de-Sevilla’ cultivar, except for the ferulic acid and luteolin, as well the TPC that varied as did the rooting parameter. At the end of the rooting trial (60 days), luteolin in `Verdial de Huévar’ and `Gordal sevillana’ cultivars and ferulic acid in `Lechin de Sevilla’ were the phenolics exclusively found in the highest concentrations. Time did not affect vanillin and oleuropein, although in the case of high-rooting cultivars, values for these compounds were almost constant, while in low- or medium-rooting cultivars, by general, increased or decreased, respectively. The Random Forest algorithm allowed to predict from a complex number of variables, which affected the rooting ability of olive cuttings independently of the cultivar and auxin treatment, finding that luteolin was the best indicator over time.

Bioactive polyphenolic compounds and antioxidant potentials of two leafy vegetables in Bangladesh: the Momordica charantia and the Ipomoea aquatica

Momordica charantia and Ipomoea aquatica leaves are two green leafy vegetables in Bangladesh that are commonly consumed considering their characteristic taste and abundant availability in nature. The aim of this study was to determine the available bioactive phenolic constituents as well as total flavonoid content (TFC), tannin content (TTC), phenolic content (TPC), antioxidant activity (TAA) and DPPH radical scavenging activity (IC50) of the ethanolic extracts of M. charantia (MCE) and I. aquatica (IAE). HPLC–DAD and UV–visible spectrophotometer were used to determine the phenolic compounds and antioxidant properties, respectively. In this study, TFC, TTC, TPC, TAA and IC50 values were in the order of IAE (40.73 ± 1.0 mg QE/g) > MCE (34.60 ± 0.46 mg QE/g); MCE (40.93 ± 0.70 mg TAE/g) > IAE (31.13 ± 0.42 mg TAE/g); MCE (27.76 ± 0.58 mg GAE/g) > IAE (21.29 ± 0.43 mg GAE/g); MCE (52.03 ± 0.21 mg AAE/g) > IAE (40.77 ± 0.15 mg AAE/g) and MCE (333.22 ± 67.37 µg/mL) > IAE (560.74 ± 10.25 µg/mL). M. charantia ethanolic extracts contained five hydroxycinnamic acid: ferulic acid, chlorogenic acid, p-coumaric acid, rosmarinic acid and cinnamic acid; five flavonoids: epicatechin, quercetin, catechin, rutin hydrate and myricetin; two hydroxybenzoic acid: gallic acid and vanillic acid; and one phenolic aldehyde: vanillin. Whereas, I. aquatica extracts possessed four hydroxycinnamic acid: chlorogenic acid, p-coumaric acid, trans-ferulic acid and trans-cinnamic acid; four flavonoids: epicatechin, quercetin, catechin, and rutin hydrate; two hydroxybenzoic acid: gallic acid and vanillic acid; and one phenolic aldehyde:vanillin. These underutilised sources of leafy vegetables may be used to develop functional foods by emphasising their remarkable bioactive components.Graphical

Syringaldehyde Exhibits Antibacterial and Antioxidant Activities against Mycobacterium marinum Infection.

Tuberculosis (TB) is caused by infection with Mycobacterium tuberculosis (Mtb), which has a unique resistance to many antimicrobial agents. TB has emerged as a significant worldwide health issue because of the rise of multidrug-resistant strains causing drug-resistant TB (DR-TB). As a result, the development of new drugs or effective strategies is crucial for patients with TB. Mycobacterium marinum (Mm) and Mtb are both species of mycobacteria. In zebrafish, Mm proliferates and forms chronic granulomatous infections, which are similar to Mtb infections in lung tissue. Syringaldehyde (SA) is a member of the phenolic aldehyde family found in various plants. Here, we investigated its antioxidative and antibacterial properties in Mm-infected cells and zebrafish. Our results demonstrated that SA inhibits Mm-infected pulmonary epithelial cells and inhibits the proliferation of Mm in Mm-infected zebrafish, suggesting that SA provides an antibacterial effect during Mm infection. Further study demonstrated that supplementation with SA inhibits the production of malondialdehyde (MDA) and reactive oxygen species (ROS) and increases the levels of reduced glutathione (GSH) in Mm-infection-induced macrophages. SA inhibits the levels of MDA in Mm-infected zebrafish, suggesting that SA exerts antioxidative effects in vivo. Additionally, we found that SA promotes the expression of NRF2/HO-1/NQO-1 and the activation of the AMPK-α1/AKT/GSK-3β signaling pathway. In summary, our data demonstrated that SA exerts antioxidative and antibacterial effects during Mm infection both in vivo and in vitro and that the antioxidative effects of SA may be due to the regulation of NRF2/HO-1/NQO-1 and the AMPK-α1/AKT/GSK-3β signaling pathway.

Efficient polymalic acid production from corn straw hydrolysate by detoxification of phenolic inhibitors.

Inhibitory compounds generated from lignocellulose pretreatment would inhibit Poly (malic acid) (PMA) production by Aureobasidium pullulans, but the tolerance mechanism of A. pullulans to lignocellulosic inhibitor is poorly understood. In this study, the cellular response of A. pullulans to lignocellulosic inhibitor stress was studied. Among the three groups of inhibitors (furans, weak acids and phenolic aldehydes), phenolic aldehyde was the dominant inhibitor for PMA production. Phenolic aldehyde was mainly converted into phenolic alcohol by A. pullulans, and phenolic alcohol also exhibited severe inhibition on PMA production. Furthermore, the effect of detoxification methods on inhibitor-removal and PMA fermentation was investigated, both CaCO3 and overliming presented poor detoxification effect, whereas resin H103 could remove both furan derivatives and phenolic compounds efficiently, thereby producing 26.27g/L of PMA with a yield of 0.30g/g in batch fermentation. This study will be beneficial for the development of PMA production from lignocellulosic biomass.

Root exudate fingerprint of Brachiaria humidicola reveals vanillin as a novel and effective nitrification inhibitor.

Introduction: Biological Nitrification Inhibition (BNI) is defined as the plant-mediated control of soil nitrification via the release of nitrification inhibitors. BNI of Brachiaria humidicola (syn. Urochloa humidicola) has been mainly attributed to root-exuded fusicoccane-type diterpenes, e.g., 3-epi-brachialactone. We hypothesized, however, that BNI of B. humidicola is caused by an assemblage of bioactive secondary metabolites. Methods: B. humidicola root exudates were collected hydroponically, and metabolites were isolated by semi-preparative HPLC. Chemical structures were elucidated by HRMS as well as 1D and 2D NMR spectroscopy. Nitrification inhibiting potential of isolated metabolites was evaluated by a Nitrosomonas europaea based bioassay. Results and discussion: Besides previously described brachialactone isomers and derivatives, five phenol and cinnamic acid derivatives were identified in the root exudates of B. humidicola: 2-hydroxy-3-(hydroxymethyl)benzaldehyde, vanillin, umbelliferone and both trans- and cis-2,6-dimethoxycinnamic acid. Notably, vanillin revealed a substantially higher nitrification inhibiting activity than 3-epi-brachialactone (ED50 ∼ 12.5μg·ml-1, ED80 ∼ 20μg·ml-1), identifying this phenolic aldehyde as novel nitrification inhibitor (NI). Furthermore, vanillin exudation rates were in the same range as 3-epi-brachialactone (1-4μg·h-1·g-1 root DM), suggesting a substantial contribution to the overall inhibitory activity of B. humidicola root exudates. In relation to the verification of the encountered effects within soils and considering the exclusion of any detrimental impact on the soil microbiome, the biosynthetic pathway of vanillin via the precursor phenylalanine and the intermediates p-coumaric acid/ferulic acid (precursors of further phenolic NI) might constitute a promising BNI breeding target. This applies not only to Brachiaria spp., but also to crops in general, owing to the highly conserved nature of these metabolites.

A Regulable Polyporous Graphite/Melamine Foam for Heat Conduction, Sound Absorption and Electromagnetic Wave Absorption.

To reduce electromagnetic interference and noise pollution within communication base stations and servers, it is necessary for electromagnetic wave absorption (EWA) materials to transition from coating to multifunctional devices. Up to now, the stable and effective integration of multiple functions into one material by a simple method has remained a large challenge. Herein, a foam-type microwave absorption device assembled with multicomponent organic matter and graphite powder is synthesized by a universal combination process. Melamine and phenolic aldehyde amine work as the skeleton and cementing compound, respectively, in which graphite is embedded in the cementing compound interconnected into the mesoscopic 3D electric conductive and heat conductive network. Interestingly, the prepared flexible graphite/melamine foam (CMF) delivers a great EWA performance, with a great effective absorption bandwidth of 9.8GHz, ultrathin thickness of 2.60mm, and a strong absorption reflection loss of -41.7dB. Moreover, the CMF possesses porosity and flexibility, endowing it with sound absorption ability. The CMF is unique in its integration of EWA, heat conduction, sound absorption, and mechanical robustness, as well as its cost-effective and scalable manufacturing. These attributes make CMF promising as a multifunctional device widely used in communication base stations, servers, and chips protection.

QUERCETIN, VANILLIN AND UMBELLIFERON QUANTIFICATION IN THE TISSUE OF BROILER CHICKENS DIETARY SUPPLEMENTED WITH THESE COMPOUNDS

Relevance. Plant-derived compounds are attractive alternative to antibiotic growth promoters in livestock and poultry production. In our previous study, dietary supplementation of broiler chickens with the flavonoid quercetin, the phenolic aldehyde vanillin, and the o-hydroxycinnamic acid lactone umbelliferon (7-hydroxycoumarin) modulated the ceca microbiome, reduced systemic inflammation, and increased production efficiency, as meas-ured by the EPEF index. Objectives. To evaluate the content of free and conjugated (glucuronidated) quercetin, vanillin and umbelliferon in the muscles and liver of broiler chickens fed a 35-day basic diet supplemented with these compounds. Material and methods. Quercetin, vanillin and umbelliferon were extracted with acetonitrile and formic acid, evaporated and re-dissolved in deion-ized water, and then purified using HLB cartridges. To release the conjugated compounds, hydrolysis with glucuronidase/arylsulfatase was additionally performed. The resulting samples were analyzed by HPLC-MS using a LCMS-8050 gas chromatograph - mass spectrometer (Shimadzu Corporation, Ja-pan) with LabSolutions software installed. Results. Tissue samples from broiler chickens fed quercetin did not contain this compound in a detectable concentration range, which may be a con-sequence of the effective quercetin metabolism by intestinal microflora and xenobiotic inactivation systems. Surprisingly, quantification of vanillin showed its presence in all analyzed samples, regardless of presence or absence in supplements. This result cannot be interpreted unequivocally and is currently speculated to be due to vanillin or similar cross-reacting substances in the basic diet. Umbelliferon concentrations of 17 ng/g (free) and 125 ng/g (sum of free and conjugated forms) were detected in only one liver sample of broiler chickens that received this compound at the maximum dosage (3.0 mg per 1 kg of feed). Conclusion. The absence or low accumulation of free and glucuronidated quercetin, vanillin and umbelliferon in the muscles and liver of diet-supplemented broiler chickens has been shown. This result indicates the safety of these plant-derived molecules in poultry production without possible migration through food chains.

Investigation of Polyvinyl Alcohol–Phenolic Aldehyde–Polyacrylamide Gel for the Application in Saline Oil Reservoirs for Profile Modification

Investigation of Polyvinyl Alcohol–Phenolic Aldehyde–Polyacrylamide Gel for the Application in Saline Oil Reservoirs for Profile Modification

Fluorometric investigation of boric acid-pyridoxal 5′ phosphate interaction: A turn-on-fluorescence assay for the detection of boric acid in water bodies and fetal bovine serum

Boron is a trace element that is beneficial to plants as well as human and animal health. Boron supplementation is beneficial for absorbing vitamin D and magnesium, activating antioxidant enzymes and anticancer treatments. However, environmental accumulation of boron exceeding the permissible limit harms plants, animals and humans. Boric acid (BA), a form of boron, is known to interact with biomolecules such as NAD+/NADH, vitamin C, vitamin D, vitamin B1 and vitamin B6 determined through techniques like NMR, mass spectrometry, and FTIR. The fluorescence interaction of BA with the biologically active form of vitamin B6, Pyridoxal 5′ phosphate (PLP), has not been explored to date. Therefore, this study reports the interaction mechanism of BA with PLP via fluorescence spectroscopy analysis. The absorption, excitation and fluorescence lifetime measurements indicate that BA may form a complex through the mono or di-esterification of the phenolic hydroxyl group and aldehyde of PLP at different pH, forming the boronate esters. BA addition enhanced the fluorescence intensity of PLP by 12–22-fold in phosphate buffer (at acidic, neutral, and basic pH conditions). On the other hand, in citrate buffer at pH 4.0, BA enhanced PLP fluorescence by 28-fold. The binding constant for BA in phosphate buffer and citrate buffer was found to be 173 mol−1·L and 623 mol−1·L, respectively. At the same time, the detection limit for BA was found to be 445 μg/L and 212 μg/L in respective buffers. Therefore, PLP was used as a turn-on fluorescent probe to detect and quantify BA in water bodies and fetal bovine serum (FBS). The developed method successfully detected BA in environmental water bodies, achieving an average recovery rate of 99.84% (with a relative standard deviation (RSD) of 0.38%) in phosphate buffer and 81.59% (RSD, 4.56%) in citrate buffer. Furthermore, detecting BA in PLP-spiked FBS has been demonstrated in citrate buffer at pH 4.0, yielding an average recovery rate of 108.25% (RSD, 3.19%). Therefore, this study provides a basis for understanding the interaction of biomolecules like vitamins with boronates which aid in development of novel boronate based therapeutics and also helps in understanding the metabolic reactions of vitamin derivatives using fluorescence spectroscopy.

Phytochemical analysis by LC MS/ MS and in vitro antioxidant activity of the Algerian endemic plant Dianthus sylvestris subsp. aristidis (Batt.) Greuter &amp; Burdet

&lt;p&gt;The present work aimed to carry out the phytochemical analysis and antioxidant activity of hydro-methanolic, ethyl acetate and butanolic extracts of Dianthus sylvestris subsp, aristidis (Batt,) Greuter &amp;amp; Burdet leaves. Phenolics, flavonoids and flavonols contents were measured by the Folin-Ciocalteu reagent and the aluminum chloride (AlCl3) method respectively. Phytochemical analysis was determined by using LC-ESI-MS/MS method. Antioxidant activity, in vitro, was evaluated by six different assays including: DPPH scavenging, ABTS cation radical, Ferrous ions chelating, Phenanthroline, Reducing power and Silver nanoparticle. The findings showed that the butanolic extract was found to be higher in phenolics and flavonoids contents (121.45 ± 1.87 μg GAE/mg extract and 57.09±0.14 μg QE/mg extract respectively). While ethyl acetate extract was found to be higher in falvonols contents (41.90±0.98µg QE/mg extract). The LC-ESI-MS/MS analysis of ethyl acetate and butanolic extracts revealed the presence of fifteen compounds among which: four phenolic acids, five flavonoids, one phenolic aldehyde and three vitamins, with P- coumaric acid, Hesperetin, Vanillin, Ascorbic Acid as major compounds respectively. The butanolic and ethyl acetate extracts exhibited the highest antioxidant activity in Phenanthroline assay (A0,5: 17.75± 0.72 µg/mL and A0.5: 21.02 ± 0.43 µg/mL respectively). On the basis of the significant findings, D. sylvestris subsp, aristidis would be recommended as a new potential source of natural antioxidant for pharmaceutical industries.&lt;/p&gt;&#x0D;

Therapeutic aspects of biologically potent vanillin derivatives: A critical review

4-hydroxy 3-methoxy benzaldehyde (Vanillin) is an aromatic phenolic aldehyde with unique chemical properties and pharmacological impact. Because of its potent nature, it acts as a lead for drug discovery and development techniques. Heterocyclic compounds with vanillin moiety were efficacious and thrive against many emerging infectious diseases, which can also lead to develop numerous fused heterocyclic vanillin derivatives and various heterocyclic compounds such as pyrimidines, quinoxalines, imidazoles or thiazoles. Greener-mediated synthesis is a sustained chemical reaction used to synthesize hazardless vanillin derivatives with a high yield of product in desired time. Due to its several reasonable modifications with high bioactivity, vanillin moiety can be used to develop various potent derivatives like vanillin-based ferrocenyl chalcone derivatives, vanillin-hydrazone derivatives, Schiff base and Mannich base-based derivatives, pyrazoline vanillin-based derivatives, triazole-based vanillin derivatives and vanillin hybrids plays a crucial role in the coordination chemistry. These derivatives exhibited plenty of biological applications, which include anticancer, antioxidant, antibacterial, antitubercular, antimalarial, antiviral, anti-inflammatory, anti-Alzheimer and anti-diabetic effects. Hence, this review focuses on the significance of vanillin derivatives responsible for biological activity.&#x0D; Keywords: Vanillin; 4-hydroxy 3-methoxy benzaldehyde; Vanillin derivatives; Antimicrobial; Anticancer; Biological applications

Walatimine (Vanillyl Butyl Imine): A New Ketimine from Schiff Base Synthesis and Evaluation of its Antioxidant, Antibacterial and Antifungal Properties

Background of study: Vanillin is a white crystalline compound which is a phenolic aldehyde with a balsamic flavour. It is widely obtained from vanilla bean-pods amongst very many other sources. This compound and some of its derivatives possess diverse activities including anticancer, anti- inflammatory, antioxidant, antibacterial and antifungal amongst others. Hence, the import of this study. Objectives: The growing concerns about the deleterious actions of free radical oxygenated species (FROS) in the human body have become a huge concern to the scientific world. These chemical species continually devastate the human cells, tissues and organs leading to different pathophysiological conditions and neurodegenerative disorders. Also, the noticeable microbial resistance to antibiotics and antifungal drugs have prompted the search for lead compound(s) with the aim of chemically modifying its/their molecular structure(s) or synthesizing other compounds from reactions involving them such as Schiff base synthesis. The search for novel pharmaceutically active compounds with the aim of ameliorating these conditions led to the choice of vanillin. Methodology: Vanillin was subjected to the Schiff base synthesis. It was reacted separately with amines (aromatic and aliphatic amine) leading to the bases in the presence of acid. The melting points, refractive indices and optical rotations of the vanillin and the Schiff bases were obtained. The antioxidant activity (IC50) of the lead compound and bases was determined employing the DPPH (2, 2-diphenyl-1-picrylhydrazyl hydrate) bench-top assay test. Comparison of the obtained antioxidant activities was done to determine if any improvements could be noticed in the synthesized bases. Also, the agar-in-hole diffusion method was adopted for screening vanillin and the synthesized bases against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeriginosa and Candida albicans for antibacterial and antifungal activities respectively. Results: The identities of the synthesized Schiff bases have been revealed to be vanillyl butyl imine (W) a new ketimine referred to by the trivial name- Walatimine and vanillin-2,4-dinitrophenyl hydrazone (Vdnp) respectivelyusing a combination of physico-chemical determinations and IR spectral technique. Vanillin and (W) demonstrated marginal antioxidant activity of IC50 of 0.52 and 0.50 μg/mL respectively while Vdnp gave a remarkably significant IC50 of 0.48 and which compare favourably with 0.46 μg/mL elicited by Vitamin C (a standard antioxidant drug). The antibacterial and antifungal activities elicited by both W and Vdnp were concentration dependent. Furthermore, Vdnp was comparably more bacteriostatic than W against the test bacteria though it was inactive against Ps. aeriginosa. However, vanillyl butyl imine (W) was slightly more anti-candidal against C. albicans than vanillin-2,4-dinitrophenyl hydrazone (Vdnp). Conclusion: The results from this study indicate that vanillin-2,4- dinitrophenyl hydrazone (Vdnp) obtained from the condensation reaction of vanillin and an aromatic amine affords a comparably better antioxidant activity than W obtained from vanillin reacting with an aliphatic amine. Both W and Vdnp demonstrated remarkable antibacterial and antifungal activities hence, these two synthesized Schiff bases can be lead candidate compounds in the search for newer and more efficacious antioxidant and antimicrobial agents and in further structural activity relationship studies (SARS) and as well as in formulation studies in drug development.

Vanillin attenuates CdCl2-induced cytotoxicity in isolated human erythrocytes

Cadmium is a toxic heavy metal with no physiological role in the human body. Cadmium has high mobility due to its widespread industrial use, with no safe and effective therapeutic management. Cadmium toxicity manifests by increasing oxidative stress in target cells. We have explored the potential role of vanillin, a plant phenolic aldehyde and antioxidant, in mitigating cadmium chloride (CdCl2) induced hemotoxicity using isolated human erythrocytes. CdCl2 was added to erythrocytes, in the absence and presence of vanillin. Incubation of erythrocytes with CdCl2 alone inhibited methemoglobin reductase and enhanced methemoglobin level. Heme degradation and release of free iron (Fe2+), along with protein and membrane lipid oxidation, were also increased. A CdCl2-induced enhancement in reactive oxygen and nitrogen species was also seen, lowering the overall antioxidant power of cells. However, pre-incubation of erythrocytes with vanillin resulted in significant decreased generation of reactive species and prevented heme degradation and heme oxidation. Vanillin augmented the erythrocyte antioxidant capacity and reinstated the activities of major antioxidant, plasma membrane-bound and glucose metabolism enzymes. Scanning electron microscopy showed that CdCl2 treatment led to the formation of echinocytes which was prevented by vanillin. In all cases, no harmful effects of vanillin alone were seen. Thus, vanillin alleviates the toxicity of cadmium and can be potentially employed as a chemoprotectant against the damaging effects of this heavy metal.

The multifactorial role of vanillin in amelioration of aluminium chloride and D-galactose induced Alzheimer's disease in mice

The onset and progression of Alzheimer's disease (AD) are influenced by a variety of factors. These include oxidative stress, overexpression of acetylcholinesterase (AChE), depletion of acetylcholine levels, increased beta-secretase mediated conversion of Amyloid Precursor Protein (APP) to Amyloid Beta (Abeta), accumulation of Abeta oligomers, decrease in Brain Derived Neurotrophic factor (BDNF) and accelerated neuronal apoptosis due to elevated levels of caspase-3. The currently available therapeutic approaches are inadequate in affecting these pathological processes except maybe the overexpression of AChE (AChE inhibitors like donepezil, rivastigmine). There is an urgent need to develop disease modifying pharmacotherapeutic interventions which have appreciable safety and cost effectiveness. From previously reported in vitro studies and a preliminary assessment of neuroprotective effect in scopolamine induced dementia-like cognitive impairment in mice, vanillin has been used as the compound of interest in the present study. Vanillin, a phytoconstituent, has been used in humans, safely, in the form of a flavouring agent for various foods, beverages, and cosmetics. Owing to its chemical nature i.e. being a phenolic aldehyde, it has an additional antioxidant property that is congruent to the desirable characteristics that are sought in a suitable novel anti-AD agent. In our study, vanillin proved to have a nootropic effect in healthy Swiss albino mice as well as an ameliorative effect in aluminium chloride and D-galactose induced AD model in mice. Apart from tackling oxidative stress, vanillin was found to reduce the levels of AChE, beta secretase, caspase-3, enhance degradation of Abeta plaques and elevate the levels of BDNF, in cortical and hippocampal regions. Vanillin is a promising candidate for being incorporated into the search for safe and effective anti-AD molecules. However, further research might be needed to warrant its application clinically.

Study on Water-Soluble Phenolic Resin Gels for High-Temperature and High-Salinity Oil Reservoir

High water cut of produced fluid is one of the most common problems in reservoir development. At present, injecting plugging agents and other profile control and water plugging technologies are the most widely used solutions. With the development of deep oil and gas resources, high-temperature and high-salinity (HTHS) reservoirs are becoming increasingly common. Conventional polymers are prone to hydrolysis and thermal degradation under HTHS conditions, making polymer flooding or polymer-based gels less effective. Phenol–aldehyde crosslinking agent gels can be applied to different reservoirs with a wide range of salinity, but there exist the disadvantage of high cost of gelants. The cost of water-soluble phenolic resin gels is low. Based on the research of former scientists, copolymers consisting of acrylamide (AM) and 2-Acrylamido-2-Methylpropanesulfonic acid (AMPS) and modified water-soluble phenolic resin were used to prepare gels in the paper. The experimental results show that the gelant with 1.0 wt% AM-AMPS copolymer (AMPS content is 47%), 1.0 wt% modified water-soluble phenolic resin and 0.4 wt% thiourea has gelation time of 7.5 h, storage modulus of 18 Pa and no syneresis after aging for 90 days at 105 °C in simulated Tahe water of 22 × 104 mg/L salinity. By comprehensively comparing the effectiveness of the gels prepared by a kind of phenolic aldehyde composite crosslinking agent and modified water-soluble phenolic resin, it is found that the gel constructed by the modified water-soluble phenolic resin not only reduces costs, but also has shorter gelation time and higher gel strength. The oil displacement experiment with a visual glass plate model proves that the forming gel has good plugging ability and thus improves the sweep efficiency. The research expands the application range of water-soluble phenolic resin gels, which has an important implication for profile control and water plugging in the HTHS reservoirs.