Methyl Nicotinate Research Articles

Integration of Electrochemical Sensing and Machine Learning to Detect Tuberculosis via Methyl Nicotinate in Patient Breath.

Tuberculosis (TB) remains a significant global health issue; making early, accurate, and inexpensive point-of-care detection critical for effective treatment. This paper presents a clinical demonstration of an electrochemical sensor that detects methyl-nicotinate (MN), a volatile organic biomarker associated with active pulmonary tuberculosis. The sensor was initially tested on a patient cohort comprised of 57 adults in Kampala, Uganda, of whom 42 were microbiologically confirmed TB-positive and 15 TB-negative. The sensor employed a copper(II) liquid metal salt solution with a square wave voltammetry method tailored for MN detection using commercially available screen-printed electrodes. An exploratory machine learning analysis was performed using XGBOOST. Utilizing this approach, the sensor was 78% accurate with 71% sensitivity and 100% specificity. These initial results suggest the sensing methodology is effective in identifying TB from complex breath samples, providing a promising tool for non-invasive and rapid TB detection in clinical settings.

Challenging the safety and efficacy of topically applied chlorogenic acid, apigenin, kaempferol, and naringenin by HET-CAM, HPLC-TBARS-EVSC, and laser Doppler flowmetry.

The integumentary system, a vital organ, constitutes a multifaceted barrier against pathogens and environmental factors, crucial for maintaining homeostasis. Intrinsic and extrinsic factors can accelerate skin aging and compromise its homeostatic functions and solar rays, particularly ultraviolet (UV) radiation, pose a significant risk for skin cancer. Polyphenols are molecules that donate hydrogen or electrons, preventing the oxidation of substances, such as lipids, or the formation of inflammatory mediators by cyclooxygenase enzymes. This study explored the in vitro safety, by HET-CAM (hen's egg test on chorioallantoic membrane), and protective effects of polyphenols (chlorogenic acid, apigenin, kaempferol, and naringenin) against stratum corneum UV-induced lipid peroxidation using an innovative method, the HPLC-TBARS-EVSC (high-performance liquid chromatography-thiobarbituric acid reactive substances-ex vivo stratum corneum), and a stress test using methyl nicotinate and laser Doppler flowmetry to establish in vivo the samples' topical anti-inflammatory ability. An aqueous gel containing 0.1% w/w of each polyphenol was formulated using ammonium acryloyldimethyltaurate/VP copolymer. Through the utilization of the HET-CAM assay for in vitro safety assessment, chlorogenic acid, apigenin, kaempferol, and naringenin were classified as non-irritating active ingredients. This classification was based on their lack of adverse reactions within the vascularization of the chorioallantoic membrane. To assess the protective capabilities of four polyphenols against lipid peroxidation in the stratum corneum, the HPLC-TBARS-EVSC protocol was conducted. It was observed that only naringenin exhibited a significant reduction in epidermal lipoperoxidation, indicating superior anti-radical potential. Conversely, chlorogenic acid, apigenin, and kaempferol displayed a pro-oxidant profile under the specified test conditions. The laser Doppler flowmetry suggested the anti-inflammatory potential of naringenin, kaempferol, and chlorogenic acid, with naringenin showing superior efficacy involving all parameters quantified. Naringenin emerged as the only polyphenol capable of reducing the intensity of the inflammatory response induced by methyl nicotinate solution in the participants, compared to the blank gel and the untreated area. This comprehensive investigation underscores the diverse protective roles of polyphenols in skin health, emphasizing naringenin's notable anti-radical and anti-inflammatory properties.

Ligand Environment and Light: Two Triggers for Controlling Cytotoxicity of Ruthenium Nitrosyl Complexes

AbstractPhotoinduced nitric oxide (NO) release for complexes [RuNO(L)2(NO2)2OH], where L=methyl isonicotinate (1), ethyl isonicotinate (2), methyl nicotinate (3) and ethyl nicotinate (4) was studied in DMSO, MeCN and water solutions (PBS, CTAB) using spectroscopic methods (UV‐vis, IR, EPR) and spectrometric techniques (ESI‐MS). Additionally, we present methodological evidence for improving the calculation of the quantum yield (QY) of NO release through the utilization of a combined IR‐UV‐vis‐spectroscopy flow‐through setup. According to DFT calculations, the production of nitric oxide occurs through the photoinduced cleavage of the Ru−NO bond, triggered by irradiation at 445 or 532 nm. This cleavage is a consequence of charge transfer from the orbitals of the Ru−OH group and the equatorial ligands (HOMO, HOMO‐1) to the Ru−NO antibonding orbital (LUMO). The cytotoxicity and photoinduced cytotoxicity of the investigated compounds were assessed against the breast adenocarcinoma cell line MCF‐7. Moreover, the investigation of the lipophilic properties of compounds 1–4 unveiled a significant influence of their lipophilicity on cytotoxic behavior, allowing for the modification of cytotoxicity through changes in the ligand L or by light irradiation.

Testing the inhibition efficiency of the castor oil leaf as corrosion inhibitor of mild steel in H2SO4

This study focused on the testing of castor oil leaf as corrosion inhibitor of mild steel in H2SO4. It involved the examination of the dynamics of molecular forces at the inhibitor and mild steel interface. Findings of the study will promote industrial diversification of castor oil leaf. On the experiment, bio-molecular compounds of the leaf were identified by gas chromatography mass spectrophotometer. Then, gravimetric and potentiodynamic polarization techniques were employed, where the efficacy and type of the inhibitor were determined. Considering the gravimetric process, factors of inhibitor concentration (0.2 g/L - 1.0 g/L), temperature (303 K–333 K) and time (8 h–24 h) were considered, with the inhibitor efficiency as the response. The efficiency was determined and optimized using response surface methodology (RSM) and artificial neural network (ANN). On the other hand, potentiodynamic polarization process was used to identify the type of inhibitor. Adsorption quantities were ascertained through the subjection of the experimental raw data to various adsorption isotherms. The analyses showed that castor oil leaf contains methyl nicotinate and pyridine-4-carbohydrazide. The bio-molecular compounds possess heteroatoms (N, S and O), signifying strong corrosion inhibitive tendencies. High efficiency (96.25 %) was obtained, with ANN having better prediction capability than the RSM. Potentiodynamic polarization curves revealed castor oil leaf as mixed-type inhibitor. On the adsorption phenomenon, the process of the inhibition was best fitted by Frumkin isotherm, revealing physical adsorption mechanism of Gibb's free energy less than −40 kJ/mol. As a mixed-type inhibitor, castor oil leaf should be applied for mitigation of anodic and cathodic corrosion.

Bioinspired Collective Total Synthesis of (±)-Rhynchines A-E.

Herein, we present the first racemic total synthesis of the structurally complex monoterpene indole alkaloids rhynchines A-E, starting from commercially available methyl nicotinate and 3-(2-bromoethyl)-1H-indole. The success of our synthesis is attributed to the utilization of a bioinspired synthetic strategy, which facilitated the rapid construction of the pentacyclic core skeleton of the target molecules through biomimetic skeletal rearrangement and late-stage C-H oxidative cyclization. Additionally, silica-gel-promoted tautomerization played a crucial role as a strategic element in the chemical synthesis of rhynchines A and B.

Two undescribed compounds from Aspergillus Niger, an endophytic fungus isolated from Camellia flavida

A new naphtho-γ-pyrone dimer, asperosperma A, and a new methyl nicotinate derivative, asperosperma B, with 12 known compounds were isolated from the endophytic fungus Aspergillus niger from the stem of Camellia flavida. Their structure was elucidated by NMR, ECD spectrum, and HR-ESI-MS data. Asperosperma A exhibited a highly cytotoxicity against H460 and 4T1 cancer cells with the IC50 values were 0.37 ± 0.06 and 2.04 ± 0.79 μM, respectively. Moreover, it showed a highly sensitive against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant S. aureus.

Skin perfusion and oxygen saturation after mastectomy and radiation therapy in breast cancer patients

The pathophysiological mechanism behind complications associated with postmastectomy radiotherapy (PMRT) and subsequent implant-based breast reconstruction are not completely understood. The aim of this study was to examine if there is a relationship between PMRT and microvascular perfusion and saturation in the skin after mastectomy and assess if there is impaired responsiveness to a topically applied vasodilator (Methyl nicotinate – MN).Skin microvascular perfusion and oxygenation >2 years after PMRT were measured using white light diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) in the irradiated chest wall of 31 women with the contralateral breast as a control. In the non-irradiated breast, the perfusion after application of MN (median 0.84, 25th–75th centile 0.59–1.02 % RBC × mm/s) was higher compared to the irradiated chest wall (median 0.51, 25th–75th centile 0.21–0.68 % RBC × mm/s, p < 0.001). The same phenomenon was noted for saturation (median 91 %, 25th–75th centile 89–94 % compared to 89 % 25th–75th centile 77–93 %, p = 0.001). Eight of the women (26%) had a ≥10 % difference in skin oxygenation between the non-irradiated breast and the irradiated chest wall.These results indicate that late microvascular changes caused by radiotherapy of the chest wall significantly affect skin perfusion and oxygenation.

Microcirculatory changes in the skin after postmastectomy radiotherapy in women with breast cancer

Postmastectomy radiotherapy (PMRT) increases the risk for complications after breast reconstruction. The pathophysiological mechanism underlying this increased risk is not completely understood. The aim of this study was to examine if there is a relationship between PMRT and microvascular perfusion in the skin directly after, and at 2 and 6 months after PMRT and to assess if there is impaired responsiveness to a topically applied vasodilator (Methyl nicotinate—MN) after PMRT. Skin microvascular responses after PMRT were measured on two sites in the irradiated chest wall of 22 women before, immediately after, and at 2 and 6 months after unilateral PMRT with the contralateral breast as a control. A significant increase in basal skin perfusion was observed in the irradiated chest wall immediately after RT (p < 0.0001). At 2 and 6 months after RT, there was no longer a difference in basal skin perfusion compared to the contralateral breast and compared to baseline. Similarly, the blood flow response in the skin after application of MN was stronger immediately after RT compared to before RT (p < 0.0001), but there was no difference at later time points. These results indicate that the increased risk for complications after surgical procedures are not directly related to changes in skin perfusion and microvascular responsiveness observed after postmastectomy RT.

Reproducibility of Laser Doppler Flowmetry in gingival microcirculation. A study on six different protocols

ObjectivesLaser Doppler Flowmetry (LDF) is a non-invasive technique for the assessment of tissue blood flow, but increased reproducibility would facilitate longitudinal studies. The aim of the study was to assess the interday reproducibility of Laser Doppler Flowmetry (LDF) at rest, at elevated local temperatures, and with the use of the vasodilator Methyl Nicotinate (MN) in six interconnected protocols for the measurement of the blood supply to the microvascular bed of the gingiva. MethodsTen healthy volunteers were included. Interweek LDF measurements with custom-made acrylic splints were performed. Six protocols were applied in separate regions of interest (ROI): 1; basal LDF, 2; LDF with thermoprobe 42 °C, 3; LDF with thermoprobe 45 °C, 4; LDF with thermoprobe 42 °C and MN, 5; LDF with thermoprobe 45 °C and MN and 6; LDF with MN. ResultsIntra-individual reproducibility was assessed by the within-subject coefficient of variation (wCV) and the intraclass correlation coefficient (ICC). Basal LDF measurements demonstrated high reproducibility with wCV 11.1 in 2 min and 10.3 in 5 min. ICC was 0.9 and 0.92. wCV after heat and MN was 4.9–10.3 and ICC 0.82–0.93. The topically applied MN yielded increased blood flow. ConclusionThis is the first study evaluating the reproducibility of basal LDF compared to single or multiple vasodilatory stimuli in gingiva. Multiple collector fibers probe and stabilizing acrylic splints are recommended. Vasodilatory stimulation showed a tendency toward higher reproducibility. Furthermore, MN yields vasodilation in gingiva.

Attraction of thrips by salt forms of alkyl nicotinates and isonicotinates

Methyl and ethyl esters of nicotinic and isonicotinic acids are effective attractants for catching thrips. The salt forms of nicotinic and isonicotinic acid esters dissociate in air and gradually secrete an attractant. The use of salt forms of alkyl nicotinates or isonicotinates as thrips attractants has not been previously described. The efficiency of catching Western flower thrips in the closed ground on cucumber crops and aster flowers on blue sticky traps with dispensers containing salts of hydrochloric, phosphoric, citric and trifluoroacetic acids with methyl nicotinate was investigated. It was found that the use of dispensers with salt forms of methylnicotinate increased the catch of Western flower thrips by 1.8–2.3 times during 1 month. Dispensers with citrates of ethyl and methyl esters of nicotinic and isonicotinic acids increased the catch of thrips by 1.7–2.2 times.

Development of a green, concise synthesis of nicotinamide derivatives catalysed by Novozym® 435 from Candida antarctica in sustainable continuous-flow microreactors.

An increasing number of studies have shown that many nicotinamide derivatives exhibited extensive biological activities, such as anti-inflammatory and antitumor activity. In this paper, a green, concise synthesis of nicotinamide derivatives in sustainable continuous-flow microreactors catalysed by Novozym® 435 from Candida antarctica has been developed. Application of an easily obtainable and reusable lipase in the synthesis of nicotinamide derivatives from methyl nicotinate and amines/benzylamines reacted for 35 min at 50 °C led to high product yields (81.6-88.5%). Environmentally friendly tert-amyl alcohol was applied as a reaction medium. Substantially shorter reaction times as well as a significant increase in the product yield were obtained as compared to the batch process. This innovative approach provides a promising green, efficient and rapid synthesis strategy for pharmaceutical synthesis and further activity research of novel nicotinamide derivatives.

Chitosan supported ionic liquid, a multifaceted catalyst for streamlined and efficient synthesis of carboxylic, amino acid and carbohydrate esters.

This work presents a sustainable approach for synthesizing esters from carboxylic acids, amino acids and carbohydrates using a robust and eco-friendly chitosan-incorporated ionic liquid under solvent-free conditions. Ionic liquids with carbon chain lengths ranging from 3 to 8 were integrated into the chitosan molecule, resulting in a heterogeneous catalyst optimized for esterification reactions. Among these, the 6-carbon chain ionic liquid demonstrated superior catalytic activity and substrate tolerance. The catalyst's effectiveness was confirmed using advanced analytical techniques. The acidity of the ionic liquid was assessed by observing the interaction between the synthesized IL6 (1,4-bis(5-carboxypentyl)pyrazine-1,4-diium ([BCPPD][Br])) and p-nitroaniline via UV-Vis studies. Chitosan-IL6, an ionic liquid supported on chitosan, functions as a heterogeneous catalytic system that can be easily removed from reaction mixtures through simple filtration. It also exhibits excellent reusability, maintaining high catalytic activity and structural integrity over 10 catalytic cycles. Moreover, the methodology was successfully scaled up for the gram-scale synthesis of key compounds such as diisopropyl azodicarboxylate, methyl nicotinate, methyl cysteinate, and glucose pentaacetate, highlighting its practical viability.

The cytotoxic and antiproliferative properties of ruthenium nitrosyl complexes and their modulation effect on cytochrome P450 in the HepG2 cell line.

Ruthenium nitrosyl complexes are actively investigated as antitumor agents. Evaluation of potential interactions between cytochromes P450 (CYPs) with new compounds is carried out regularly during early drug development. In this study we have investigated the cytotoxic and antiproliferative activities of ruthenium nitrosyl complexes with methyl/ethyl esters of nicotinic and isonicotinic acids and γ-picoline against 2D and 3D cultures of human hepatocellular carcinoma HepG2 and non-cancer human lung fibroblasts MRC-5, assessed their photoinduced activity at λrad = 445 nm, and also evaluated their modulating effect on CYP3A4, CYP2C9, and CYP2C19. The study of cytotoxic and antiproliferative activities against 2D and 3D cell models was performed using phenotypic-based high content screening (HCS). The expression of CYP3A4, CYP2C9, and CYP2C19 mRNAs and CYP3A4 protein was examined using target-based HCS. The results of CYP3A4 mRNA expression were confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR). The ruthenium nitrosyl complexes exhibited a dose-dependent cytotoxic effect against HepG2 and MRC-5 cells. The cytotoxic activity of complexes with ethyl isonicotinate (1) and nicotinate (3, 4) was significantly lower for MRC-5 than for HepG2, for a complex with methyl isonicotinate (2) it was higher for MRC-5 than for HepG2, for a complex with γ-picoline (5) it was comparable for both lines. The antiproliferative effect of complexes 2 and 5 was one order of magnitude higher for MRC-5; for complexes 1, 3, and 4 it was comparable for both lines. The cytotoxic activity of all compounds for 3D HepG2 was lower than for 2D HepG2, with the exception of 4. Photoactivation affected the activity of complex 1 only. Its cytotoxic activity decreased, while the antiproliferative activity increased. The ruthenium nitrosyl complexes 1-4 acted as inducers of CYP3A4 and CYP2C19, while the complex with γ-picoline (5) induced of CYP3A4. Among the studied ruthenium nitrosyl complexes, the most promising potential antitumor compound is the ruthenium compound with methyl nicotinate (4).

Protective and anti-inflammatory effects of a dermocosmetic formulation containing a combination of vitamins

The exposome accelerates the skin aging process, highlighting the need to use cosmetics capable of repairing the damage and maintaining the skin's physiological conditions. Thus, the present study aims to evaluate the potential anti-inflammatory and protective action of a dermocosmetic formulation combination of vitamins. For this, a gel-cream formulation added or not with 3% of ascorbyl tetraisopalmitate and 1% of D-panthenol was developed. The stability and sensory properties of these formulations were evaluated. In addition, a short-term clinical efficacy study of the formulations was carried out for 7 days. After this period, measurements were taken in terms of transepidermal water loss and blood microcirculation by Laser Doppler at the initial time and after the application of methyl nicotinate. The results showed that the formulations remained stable during the study period and showed pseudoplastic non-Newtonian behavior. In addition, the association of vitamins was effective in the protection of the skin against the effects of methyl nicotinate by reducing blood microcirculation, which suggests that the active substances in combination can have an anti-inflammatory and protective action on the skin barrier function.

Effect of Additive Methyl Nicotinate on Electrochemical Behavior of Nickel–Copper Alloy Electrodeposition in ChCl-EG Deep Eutectic Solvents

Effect of Additive Methyl Nicotinate on Electrochemical Behavior of Nickel–Copper Alloy Electrodeposition in ChCl-EG Deep Eutectic Solvents

Effect of L-4-Thiazolylalanine (Protinol™) on skin barrier strength and skin protection.

Skin barrier properties are critical for maintaining epidermal water content, protecting from environmental factors and providing the first line of defense against pathogens. In this study, we investigated the non-proteinogenic amino acid L-4-Thiazolylalanine (L4) as a potential active ingredient in skin protection and barrier strength. L4 on wound healing, anti-inflammatory and anti-oxidant properties were evaluated using monolayers and 3D skin equivalents. The transepithelial electrical resistance (TEER) value was used in vitro as a strong indicator of barrier strength and integrity. Clinical L4 efficacy was assessed for the evaluation of the skin barrier integrity and soothing benefits. In vitro treatments of L4 show beneficial effects in wound closure mechanism, and we demonstrate that L4 anti-oxidant benefits with markedly increased HSP70 and decreased reactive oxygen species production induced by UVs exposure. Barrier strength and integrity were significantly improved by L4, confirmed clinically by an increase in 12R-lipoxygenase enzymatic activity in the stratum corneum. In addition, soothing benefits of L4 have been shown clinically with the decrease in redness after methyl nicotinate application on the inner arm and the significant reduction of the erythema and the skin desquamation on the scalp. L4 delivered multiple skin benefits by strengthening the skin barrier, accelerating the skin repair process as well as soothing the skin and the scalp with anti-inflammaging effects. The observed efficacy validates L4 as a desirable skincare ingredient for topical treatment.

Absorption wavelength (TD-DFT) and adsorption of metal chalcogen clusters with methyl nicotinate: Structural, electronic, IRI, SERS, pharmacological and antiviral studies (HIV and omicron)

The DFT B3LYP-LAND2DZ technique is used to examine interactions of Methyl nicotinate with copper selenide and zinc selenide clusters. The existence of reactive sites is determined using ESP maps and Fukui data. The energy variations between HOMO and LUMO are utilised to calculate various energy parameters. The Atoms in Molecules and ELF (Electron Localisation Function) maps are employed to investigate the topology of the molecule. The Interaction Region Indicator is used to determine the existence of non-covalent zones in the molecule. The UV–Vis spectrum using the TD-DFT method and DOS graphs are used to obtain the theoretical determination of electronic transition and properties. Structural analysis of the compound is obtained using theoretical IR spectra. To explore the adsorption of copper selenide and zinc selenide clusters on the Methyl nicotinate, the adsorption energy and theoretical SERS spectra are employed. Furthermore, pharmacological investigations are carried out to confirm the drug's non-toxicity. The compound's antiviral efficacy against HIV and Omicron is demonstrated via protein-ligand docking.

Revealing the Protective Effect of Topically Applied Cymbopogon citratus Essential Oil in Human Skin through A Contact Model

Preparations of the Cymbopogon citratus leaves are used in folk medicine for the treatment of inflammatory processes. The present study investigated the proposed anti-inflammatory properties of C. citratus essential oil (EOCC) in human skin in vivo using the methylnicotinate (MN) microinflammation skin model. Skin exposure to MN causes a disturbance that triggers the production of reactive oxygen species and evokes a short duration microinflammatory reaction that might be explored to meet this objective. Fourteen participants of both sexes were selected after providing informed consent. Three areas (3 cm × 3 cm) were drawn on both forearms. One randomly chosen area was treated for 14 days, twice a day, with a polyacrylic acid gel containing 5% EOCC. Remaining areas were used as controls. Results revealed a clear protective effect at the EOCC-treated site. The MN reaction showed significantly lower transepidermal water loss, blood perfusion, erythema, and edema when compared with the other areas. Furthermore, the methodology here proposed is an innovative approach to study the clinical impact of these substances on human skin, contributing to an evidence-based support regarding the interest of using these products in human health.

Attenuated niacin response is associated with a subtype of first-episode drug-naïve psychosis characterized as serious negative symptoms.

Although the phenomenon of attenuated niacin response (ANR) has been widely replicated in some patients with first-episode psychosis (FEP), its relevance to the negative symptoms (NS) of psychosis remains unclear. Total of 240 patients with drug-naïve FEP and 101 healthy controls (HCs) were recruited, and 209 were followed up for 1year. Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS), and niacin-induced responses were measured using laser Doppler flowmetry. We calculated the log-transform EC50 [concentration of methyl nicotinate required to elicit a half-maximal blood flow (MBF) response] and MBF values. Core-NS was generated by factor analysis of the PANSS-NS subscale and cluster analysis to produce subtypes. Significant differences were found in the log10 (EC50) values between the FEP and HC groups (p < 0.001), supporting the ANR in patients with FEP. A higher NS severity was found in the ANR subgroup than that in other patients. Factor analysis determined that a two-dimensional model included core NS and rigidity of thinking. The log10 (EC50) value was significantly associated with only the core NS. Cluster analysis revealed three subtypes-36.7% (cluster-1, n = 88), 16.7% (cluster-2, n = 40), and 46.7% (cluster-3, n = 112). Cluster-2 characterized by extensive NS appeared to have a moreremarkable ANR and less symptomatic improvement than those with other clusters during follow-up. No significant changes were found in the niacin response trajectories between the baseline and follow-up. Our findings indicate a significant correlation between ANR and core NS in patients with FEP. ANR may be a potential biomarker for certain subtypes with NS-dominated characteristics and poor symptomatic remission.

Dual-function sensors based on carbon dots derived from corncobs for methyl nicotinate detection in solution and vapor phases

Dual-function sensors based on carbon dots: methyl nicotinate detection in solution and vapor phases via fluorescence and electronic nose methods.