Ethyl Acetate Research Articles

Identification and Molecular Docking Analysis of Angiotensin-Converting Enzyme Inhibitors from Finger Millet (Eleusine coracana).

Hypertension remains a significant global health concern, contributing significantly to cardiovascular diseases and mortality rates. The inhibition of angiotensin-converting enzyme (ACE) plays a crucial role in alleviating high blood pressure. We investigated the potential of finger millets (Eleusine coracana) as a natural remedy for hypertension by isolating and characterizing its ACE-inhibitory compound. First, we evaluated the ACE-inhibitory activity of the finger millet ethanol extract and subsequently proceeded with solvent fractionation. Among the solvent fractions, the ethyl acetate fraction exhibited the highest ACE inhibitory activity and was further fractionated. Using preparative high-performance liquid chromatography, the ethyl acetate fraction was separated into four subfractions, with fraction 2 (F2) exhibiting the highest ACE inhibitory activity. Subsequent 1H-nuclear magnetic resonance (NMR) and 13C-NMR analyses confirmed that the isolated compound from F2 was catechin. Furthermore, molecular docking studies indicated that catechin has the potential to act as an ACE inhibitor. These findings suggest that finger millets, particularly as a source of catechin, have the potential to be used as a natural antihypertensive.

Preparing a microemulsion-loaded hydrogel for cleaning wall paintings and coins

Removing unwanted materials, such as organic coatings and soil, from the cultural relic surface is a complex and significant task in the field of cultural heritage conservation. Microemulsion-loaded gel can effectively and safely remove those organic coatings and soil. Here, we employed a simple solvent exchange strategy to prepare a microemulsion-loaded polyvinyl alcohol/polyethyleneimine (PVA/PEI) hydrogel. First, PVA and PEI were dissolved into DMSO to form a gel. Then, the gel was immersed into a microemulsion composed of water, ethyl acetate, propylene carbonate, sodium dodecyl sulfate, and 1-pentanol to exchange DMSO. Microemulsion-loaded PVA/PEI hydrogel can be synthesized by completely substituting DMSO. To investigate the microstructure, rheological properties, and mechanical properties of the gel, scanning electron microscopy, a rheometer, and a universal testing machine were used, respectively. Fourier transform infrared (FT-IR) analysis was conducted to explore the synthesis mechanism and confirm the successful loading of microemulsion within the microemulsion-loaded PVA/PEI hydrogel. Furthermore, FT-IR, a depth-of-field microscope, and a glossmeter were utilized to evaluate the cleaning efficiency of the microemulsion-loaded PVA/PEI hydrogel for removing animal glue and soil from the surfaces of cultural relics. Moreover, an X-ray fluorescence spectrometer was used to analyze the element component of the ancient coin. The application results showed that the microemulsion-loaded PVA/PEI hydrogel can effectively remove animal glue from an ancient wall painting surface. Moreover, it is capable of removing soil from an ancient coin surface as well, which helped to confirm the age of the coin. This offers a novel method to prepare microemulsion-loaded hydrogel and demonstrates great potential in the cleaning for cultural heritage.

Biodegradation and antimicrobial capability-induced heavy metal resistance of the marine-derived actinomycetes Nocardia harenae JJB5 and Amycolatopsis marina JJB11.

Currently, heavy metal-resistant (HMR) marine actinomycetes have attracted much attention worldwide due to their unique capabilities. In this study, 27 marine-derived actinomycetes were isolated from coastal beaches in the Arabian Gulf of Al-Jubail in Saudi Arabia and screened for resistance to 100 mg/L of the heavy metals Cd2+, Cr6+, Cu2+, Fe2+, Pb2+, and Ni2+ using different assay techniques. Six isolates were selected as HMRs, of which two isolates, JJB5 and JJB11, exhibited the highest maximum tolerance concentrations (200- > 300 mg/L). Both isolates were the highest among six-HMR screened for their biodegradation potential of plastics low-density polyethylene, polystyrene, and polyvinyl chloride, recording the highest weight loss (15 ± 1.22 - 65 ± 1.2%) in their thin films. They also showed the highest biodegradability of the pesticides acetamiprid, chlordane, hexachlorocyclohexane, indoxacarb and lindane, indicating promising removal capacities (95.70-100%) for acetamiprid and indoxacarb using HPLC analysis. Additionally, the cell-free filtrate (CFF) of both isolates displayed the highest antimicrobial activity among the six-HMR screened against a variety of microbial test strains, recording the highest inhibition zone diameters (13.76 ± 0.66 - 26.0 ± 1.13 mm). GC‒MS analyses of the ethyl acetate extract of their CFFs revealed the presence of diverse chemical compounds with a multitude of remarkable biological activities. Based on their spore morphology and wall-chemotype, they were assigned to the nocardioform-actinomycetes. Furthermore, their phenotypic characteristics, together with 16S rRNA gene sequencing (OR121525-OR121526), revealed them as Nocardia harenae JJB5 and Amycolatopsis marina JJB11. Our results suggest that marine HMR actinomycetes are promising candidates for various biotechnological applications.

Antiseizure Activity of Mitragyna inermis in the Pentylenetetrazol-Induced Seizure Model in Mice: Involvement of Flavonoids and Alkaloids.

This study aimed to investigate whether Mitragyna inermis (Willd.) Otto Kuntze organic and aqueous extracts are able to control seizures induced by pentylenetetrazol (PTZ) in mice based on flavonoid fingerprints and alkaloidal contents. Ethanolic extract and decoction-derived fractions from roots, leaves, and stems were subjected to chromatographic fingerprinting using AlCl3 and screening for their antiseizure effects using PTZ-induced acute seizure model. From the fractions that showed potent bioactivities, plausible antiseizure alkaloids were isolated using thin layer chromatography, and their structures were elucidated using 1H NMR, 2D NMR, 13C NMR, and FAB-HR (+ve or -ve). All fractions, with the exception of the dichloromethane and hexane fractions, revealed remarkable flavonoid fingerprints. An acute PTZ-induced seizure test revealed that ethanolic extract of stem bark [500 mg/kg body weight (bw)], ethyl acetate extract of stem bark (500 mg/kg bw), and aqueous extract of leaves (300 mg/kg bw) significantly delayed the occurrence of hind limb tonic extension (HLTE); however, a non-significant delay was observed in the onset of first myoclonic jerk compared with control animals. Isolation yielded four main alkaloids: that are, pteropodine (1), isopteropodine (2), mitraphylline (3) and corynoxeine (4). Corynoxeine is a new compound derived from M. inermis. This study suggests that flavonoid fingerprints are tracers of M. inermis anticonvulsant ingredients. The stem bark ethanolic and ethyl acetate extracts and leaf aqueous extracts contain anticonvulsant bioactive principles that delay notifying the HLTE occurring in male naval medical research institute mice. Furthermore, alkaloidal contents also remain plausible bioactive anticonvulsant principles. All observations support the traditional use of M. inermis to manage epilepsy. However, further studies are needed to understand the effects of alkaloid fractions, flavonoids, and the isolated compounds as promising antiseizure agents derived from M. inermis in experimental animals.

Flavonoids and triterpenoids isolated from the ethyl acetate extract of Maytenus quadrangulata leaves.

The new flavonoid 4'-O-methylepigallocatechin 5-O-β-D-glucopyranoside (1), along with four known triterpenes (2-4), a steroid (6), and a flavonoid (7) were isolated from the ethyl acetate extract of Maytenus quadrangulata leaves. The chemical structures of the isolated compounds were determined through analysis of 1D NMR (1H and 13C) spectroscopic data, in addition to 2D NMR and spectrometric (MS) data for compound 1. This is the first report of the isolation of compounds 3-O-β-D-glucosyl-β-sitosterol (6) and 4'-O-methylepigallocatechin (7) from this species. Compounds 1 and 7 were evaluated against the bacteria Staphylococcus aureus and Klebsiella pneumoniae, but neither exhibited activity even at the highest concentration tested.

Exploring In Vitro Immunomodulatory Properties of Moss Atrichum undulatum Extracts

Bryophytes are rich sources of diverse secondary metabolites with a wide range of biological activities, including anti-inflammatory, antitumor and antimicrobial effects. The aim of this study was to investigate the chemical composition of extracts from two different genotypes (Serbian and Hungarian) of the axenic moss Atrichum undulatum and evaluate the immunomodulatory potential of the prepared extracts in vitro. Both genotypes of moss samples were cultivated in vitro and subsequently extracted in a Soxhlet apparatus with methanol or ethyl acetate. The highest concentration of total phenolic compounds was found in the methanolic extract of the Serbian genotype (54.25 mg GAE/g extract), while the ethyl acetate extract of the Hungarian genotype showed the highest concentration of phenolic acids (163.20 mg CAE/extract), flavonoids (35.57 mg QE/extract), and flavonols (2.25 mg QE/extract). The extracts showed anti-neuroinflammatory properties by reducing the production of reactive oxygen species, nitric oxide, and tumor necrosis factor alpha by lipopolysaccharide-stimulated microglial cells. Moreover, they mitigated the cytotoxic effects of the pro-inflammatory mediators produced by activated microglia on neurons. The data obtained suggest that extracts from A. undulatum moss have promising anti-neuroinflammatory and neuroprotective properties, making them interesting candidates for further research to combat neuroinflammation.

Anti-oxidant and Wound Healing Potentials of Gnetum africanum Welw and Ficus vogelii Miq Extracts

Background: Gnetum africanum and Ficus vogelii are vegetables consumed in some parts of Africa. They are used in ethno medicine for treatment of different diseases, and are particularly known to hasten wound healing. The study aimed at investigating the wound healing properties of the plants in a rat model. Materials and Methods: The powdered leaves of the two plants were successively extracted with hexane, ethyl acetate and methanol using a Soxhlet apparatus. The crude methanol extract was screened for secondary metabolites and anti-oxidant properties. The wound healing activity was evaluated using excision wound model. Thirty healthy female Wistar albino rats (150-200 kg) were used for the experiment and randomized into 5% extract + ointment, 3.5% extract + ointment, simple ointment, and gentamicin treatment groups. The ointments were administered topically daily, and wound contraction was measured every alternate day. The percentage wound closure rate and histopathology of healed wound area were determined. The antioxidant activity of the plants was determined using the DPPH scavenging activity and ferric ion reducing antioxidant power assay (FRAP). Results: The methanol extracts of both plants showed the presence tannins, alkaloids, flavonoids, saponins, and steroids in varying amounts. The antioxidant assays revealed that the extracts of both plants had good anti-oxidant properties. Extracts of Gnetum africanum at 3.5% w/w and Ficus vogelii 5% w/w exhibited potent healing activity, eliciting 100% wound closure by day 7. Conclusion: The study revealed that Gnetum africanum and Ficus vogelii have wound healing properties which scientifically justifies its use for treatment of wounds traditionally and could be developed into useful drugs for wound treatment and management.

Identification of Secondary Metabolites from Actinomycetes Isolated from the Hilly Region of Nepal

Actinomycetes are a unique class of Gram-positive bacteria with a fungus-like filamentous mycelium. They are often called ‘antibiotics factories’ because they can produce many potent secondary metabolites. At present, multidrug-resistant (MDR) pathogens are the main problem for humans and animals and to overcome this problem, more potent antibiotics are urgently required. Fortunately, Nepal has great geographical and climatic diversity serving as a home for various actinomycetes. This study identified several actinomycetes using morphological and biochemical assays from seven soil samples collected from different elevations in Nepal. The primary objective of this study was to screen the potent metabolites-producing actinomycetes. For this purpose, antimicrobial assays of seven isolates were carried out against Escherichia coli ATCC 25922, Salmonella typhi ATCC 14028, Shigella sonnei ATCC 25931, and Staphylococcus aureus ATCC 43300. The sample BT36 demonstrated the highest zone of inhibition against the tested microorganisms among others. Similarly, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of all isolates were carried out. Among them, the MIC of samples BT36, PT7, and AB1 were found to be 1.952 mg/mL, 0.012 mg/mL, and 0.029 mg/mL, respectively. Ethyl acetate extracts of resulting potent isolates PT7 and AB1 were subjected to mass spectrometric analysis. A total of 22 bioactive compounds were annotated from liquid chromatography-high resolution mass spectroscopy (LC-HRMS), including epopromycin A, myxopyronin B, gilvocarcin HE, and okilactomycin A. It is concluded that this study will be useful in setting up a strategy to isolate useful secondary metabolites from soil microbes from the hilly region of Nepal.

Phytochemical evaluation of Ziziphus mucronata and Xysmalobium undulutum towards the discovery and development of anti-malarial drugs

BackgroundThe development of resistance by Plasmodium falciparum is a burdening hazard that continues to undermine the strides made to alleviate malaria. As such, there is an increasing need to find new alternative strategies. This study evaluated and validated 2 medicinal plants used in traditional medicine to treat malaria.MethodsInspired by their ethnobotanical reputation of being effective against malaria, Ziziphus mucronata and Xysmalobium undulutum were collected and sequentially extracted using hexane (HEX), ethyl acetate (ETA), Dichloromethane (DCM) and methanol (MTL). The resulting crude extracts were screened for their anti-malarial and cytotoxic potential using the parasite lactate dehydrogenase (pLDH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, respectively. This was followed by isolating the active compounds from the DCM extract of Z. mucronata using silica gel chromatography and structural elucidation using spectroscopic techniques (NMR: 1H, 12C, and DEPT). The active compounds were then targeted against P. falciparum heat shock protein 70–1 (PfHsp70-1) using Autodock Vina, followed by in vitro validation assays using ultraviolet–visible (UV–VIS) spectroscopy and the malate dehydrogenase (MDH) chaperone activity assay.ResultsThe extracts except those of methanol displayed anti-malarial potential with varying IC50 values, Z. mucronata HEX (11.69 ± 3.84 µg/mL), ETA (7.25 ± 1.41 µg/mL), DCM (5.49 ± 0.03 µg/mL), and X. undulutum HEX (4.9 ± 0.037 µg/mL), ETA (17.46 ± 0.024 µg/mL) and DCM (19.27 ± 0.492 µg/mL). The extracts exhibited minimal cytotoxicity except for the ETA and DCM of Z. mucronata with CC50 values of 10.96 and 10.01 µg/mL, respectively. Isolation and structural characterization of the active compounds from the DCM extracts revealed that betulinic acid (19.95 ± 1.53 µg/mL) and lupeol (7.56 ± 2.03 µg/mL) were responsible for the anti-malarial activity and had no considerable cytotoxicity (CC50 > µg/mL). Molecular docking suggested strong binding between PfHsp70-1, betulinic acid (− 6.8 kcal/mol), and lupeol (− 6.9 kcal/mol). Meanwhile, the in vitro validation assays revealed the disruption of the protein structural elements and chaperone function.ConclusionThis study proves that X undulutum and Z. mucronata have anti-malarial potential and that betulinic acid and lupeol are responsible for the activity seen on Z. mucronata. They also make a case for guided purification of new phytochemicals in the other extracts and support the notion of considering medicinal plants to discover new anti-malarials.

Insights into the Volatile Flavor Profiles of Two Types of Beef Tallow via Electronic Nose and Gas Chromatography–Ion Mobility Spectrometry Analysis

In the current study, an electronic nose (E-nose) and gas chromatography–ion mobility spectrometry (GC-IMS) were employed to investigate the volatile flavor compounds (VFCs) of intense flavor beef tallow (L) and ordinary beef tallow (P). The study results indicate that an E-nose combined with an LDA and GC-IMS combined with an OPLS-DA can effectively distinguish between the two types of beef tallow. Compared with ordinary beef tallow, the E-nose sensors of intense flavor beef tallow have stronger response signals to sulfides, terpenes, and nitrogen oxides. A total of 22 compounds contribute to making the flavor of intense flavor beef tallow more typical and richer; in contrast, ethyl acetate was the main aroma-active compound found in the ordinary beef tallow. Sulfur-containing compounds and terpenoids might be the key substances that cause sensory flavor differences between the two types of beef tallow. In conclusion, the results of this study clarify the characteristics and differences of the two types of beef tallow and provide an enhanced understanding of the differences in the flavors of the two types of beef tallow.

Comprehensive Analysis of Nutrient Composition: Evaluating Vitamins, Essential Minerals, and Trace Metals in Neem (Azadirachta indica) Stem Bark Extract

The current study sought to investigate the nutrients in an aqueous extract of Neem (Azadirachta indica) stem bark. The bioactive chemical contents of Neem stem bark were isolated, separated, and studied to determine the presence of vitamins, vital minerals, and trace metals. A fresh Neem sample was collected and the sample was ground into powdered form and prepared via extraction using various solvents (n-hexane, ethyl acetate, and ethanol), and the chemical constituents were separated using the GC/MS technique. The Neem stem sample was later digested with nitric acid and hydrogen peroxide in the ratio 4:1 (acid ratio). The trace metals and important minerals in digested Neem samples were determined using an atomic absorption spectrophotometer (AAS), while Na+ and K+ were determined using a flame photometer. The results revealed that calcium is the most prevalent mineral in Neem stem bark, followed by potassium and sodium, but copper, magnesium, iron, zinc, and other minerals are present in trace amounts, while cadmium and lead are virtually missing. Furthermore, according to the results of the vitamin studies, the most abundant vitamins in Neem stem bark are vitamin B3 and vitamin C, but vitamins A, B1, B6, and B12 are present in trace amounts.

Fatty acids in Plantago asiatica seeds are responsible for the production of the pro-inflammatory mediator nitric oxide

Background: Plantago asiatica L. (Plantaginaceae) commonly grows in East Asia, with its seeds (Shazenshi), having been used as diuretic and anti-inflammatory drugs in traditional Japanese medicine. It is not known which constituents of P. asiatica seeds elicit the anti-inflammatory effects, such as reduced expression of the inducible nitric oxide synthase (iNOS) in interleukin (IL)-1β-treated hepatocytes which leads to a reduction in the pro-inflammatory mediator nitric oxide (NO). Objective: To identify the anti-inflammatory constituents of P. asiatica seeds, the anti-inflammatory activity of purified constituents was determined by assaying NO production in IL-1β-treated hepatocytes. Methods: P. asiatica seeds were extracted with 50% methanol and successively fractionated into three crude fractions with ethyl acetate (EtOAc) and n-butanol. The compounds were methylated and analyzed by gas chromatography–mass spectrometry (GC–MS). Primary cultured rat hepatocytes were prepared by collagenase perfusion, and P. asiatica seed extract (PASE), a fraction, or a compound was added to the culture medium with IL-1β and incubated at 37 °C. Potency of each fraction was determined by the Griess method for measuring the levels of nitrite in the medium. Results: PASE suppressed IL-1β-induced NO production without showing cytotoxicity, and an EtOAc-soluble fraction of PASE significantly inhibited NO production. GC–MS analysis detected 26 distinct fatty acids as their methyl esters in this fraction. Among them, three unsaturated fatty acids (linoleic, oleic, and α-linolenic acids) and palmitic acid were abundant. These unsaturated fatty acids are known to reduce NO levels. In contrast, acteoside and aucubin, which are thought to be present in the n-butanol-soluble fraction, showed only a low level of NO production suppression. Conclusion: The EtOAc-soluble fraction of PASE included many fatty acids, which may suppress the production of NO. The results imply that the anti-inflammatory activity of P. asiatica seeds may be produced by three unsaturated fatty acids. Because the fatty acids are abundant in the seeds of medicinal plants, they are likely to contribute to anti-inflammatory activity of the seeds. Keywords: Plantain seed, polyunsaturated fatty acid, Kampo medicine, hepatocyte, nitric oxide.

Separation and characterization of the antioxidant active component from Maillard reaction products in xylose-lysine system

ABSTRACT Maillard reaction products (MRPs) play a crucial role in preserving food quality due to their antioxidant capacity. In this study, we isolated and characterized the antioxidant components from MRPs using a xylose-lysine system under optimal conditions. Methylene chloride and ethyl acetate were employed for sequential extractions, and the ethyl acetate phase underwent thin-layer chromatography and silica column separation. The identified compound, 3-hydroxy-4-methyl-2(5 H)-furanone (3H4MFN), was analyzed using FT-IR, GC-MS, and NMR, revealing its volatile nature with a chemical formula of C5H6O3. Further activity analysis demonstrated that 3H4MFN exhibited higher or comparable antioxidant activity to vitamin C (VC) and vitamin B6 (VB6). This newly discovered compound shows potential as a natural antioxidant in cosmetics, food, and nutraceutical applications.

An antifungal compound secreted by termite workers, phenylacetic acid, inhibits the growth of both termite egg-mimicking fungus and entomopathogenic fungi

AbstractSocial insects live in closely related family groups but face risks of intrusion and infection by pathogenic and parasitic microbes. To cope with the microbes invading their nests and feeding sites, social insects produce various types of antimicrobial substances. Subterranean termites occupy microbe-rich decaying wood and soil at high density, expanding their nest area by exploring and feeding on wood outward from the royal chamber (room for kings and queens). Although antimicrobial agents have been identified in many termite species, few studies have investigated those used by foraging workers in decaying wood under development, which is richer in microbes than the well-sterilized royal chamber and its surroundings. Here, we report that phenylacetic acid, an antifungal aromatic compound, is secreted by foraging workers of the Japanese subterranean termite Reticulitermes speratus. The compound was detected by gas chromatography–mass spectrometry analysis of ethyl acetate extracts of shelter papers infested with the workers, and antimicrobial tests demonstrated that it inhibits the germination and/or mycelial growth of the entomopathogenic fungi (Metarhizium anisopliae and Beauveria bassiana) and the termite egg-mimicking fungus Athelia termitophila. Our study provides new insights into the antimicrobial defense mechanisms of termites, including by combining different types of antimicrobial substances secreted by different castes, and thus the survival strategy of entomopathogenic and parasitic fungi in termite nests.

Quantitative determination of lobeglitazone sulfate and glimepiride in combined tablet by robust high‐performance thin layer chromatographic method

AbstractA combination of fixed dose tablet containing 0.5 mg lobeglitazone sulfate (LBZ) and 1 mg glimepiride (GLM) has demonstrated efficacy in enhancing glycemic control in diabetes. The projected work aimed to develop and validate a high‐performance thin‐layer chromatographic (HPTLC) methodology for the precise quantification of both the drugs in tablet formulations. The HPTLC analysis utilized aluminium plates layered with silica gel 60F254, and the solvent system consisted of ethyl acetate, benzene, and hexane (4:3:1 v/v/v) followed by densitometric scanning at 238 nm. The Rf value was found to be 0.68 ± 0.001 for LBZ and 0.48 ± 0.002 for GLM. The methodology exhibited linearity in the range of 100–2000 ng/band for LBZ and 200–4000 ng/band for GLM, with correlation coefficients of 0.9988 and 0.9981, respectively. Exceptional sensitivity was observed, with detection limits of 23.86 ng/band for LBZ and 58.26 ng/band for GLM, along with quantification limits of 72.32 ng/band for LBZ and 176.55 ng/band for GLM. The method demonstrated precision (% relative standard deviation of peak area < 2) and accuracy (recovery between 97% and 102%). The suggested method is suitable for quantifying both the drugs in tablets, making it useful for routine quality control in laboratories.

Enhancing Bioactive Compound Classification through the Synergy of Fourier-Transform Infrared Spectroscopy and Advanced Machine Learning Methods

Bacterial infections and resistance to antibiotic drugs represent the highest challenges to public health. The search for new and promising compounds with anti-bacterial activity is a very urgent matter. To promote the development of platforms enabling the discovery of compounds with anti-bacterial activity, Fourier-Transform Mid-Infrared (FT-MIR) spectroscopy coupled with machine learning algorithms was used to predict the impact of compounds extracted from Cynara cardunculus against Escherichia coli. According to the plant tissues (seeds, dry and fresh leaves, and flowers) and the solvents used (ethanol, methanol, acetone, ethyl acetate, and water), compounds with different compositions concerning the phenol content and antioxidant and antimicrobial activities were obtained. A principal component analysis of the spectra allowed us to discriminate compounds that inhibited E. coli growth according to the conventional assay. The supervised classification models enabled the prediction of the compounds’ impact on E. coli growth, showing the following values for accuracy: 94% for partial least squares-discriminant analysis; 89% for support vector machine; 72% for k-nearest neighbors; and 100% for a backpropagation network. According to the results, the integration of FT-MIR spectroscopy with machine learning presents a high potential to promote the discovery of new compounds with antibacterial activity, thereby streamlining the drug exploratory process.

Skeletal Formation of Carbocycles with CO2: Selective Synthesis of Indolo[3,2-b]carbazoles or Cyclophanes from Indoles, CO2, and Phenylsilane

Skeletal Formation of Carbocycles with CO₂: Selective Synthesis of Indolo[3,2-<i>b</i>]carbazoles or Cyclophanes from Indoles, CO₂, and Phenylsilane

Solvent Effects on the Absorption and Emission Spectra of the [5-amino-1-bromoindolizin-3-yl](4-bromophenyl)methanone Molecule.

The effects of solvent on the absorption and emission spectra and dipole moments of the 5ABBM have been extensively studied in a series of solvents. The dipole moments in the excited state are observed to be greater than those in the ground-state in all the solvents studied for the chosen molecule. The dipole moment increase in the excited singlet state ranges from 2.42 to 24.14 D. The experimentally calculated ground state and excited state dipole moments were determined using the solvatochromatic shifts in the absorption and emission spectra as a function of dielectric constant (ɛ) and refractive index (n). These data are used to estimate the excited-state dipole moment using the experimentally determined ground-state dipole moment. A series of fifteen different organic solvents (toluene, methanol, n-butyl alcohol, ethyl acetate, DMS, acetonitrile, benzene, isopropyl alcohol, water, DMF, DCM, DIO, THF, ethanol, and octanol) were investigated at constant dye concentrations. Small changes in the fluorescence spectrum were observed for the different solvents; the highest fluorescence intensity was observed for DMS, and the lowest was observed for water. The Stokes shift in different solvents was studied for the 5ABBM molecule. This results in molecule being more polar in the excited state than in the ground state for the solvents used. The ground state dipole moments, HOMO-LUMO, and molecular electrostatic potential maps were also computed via ab initio calculations and evaluated via Gaussian 09W software.

Extraction of Natural Food Color from Tomato, Carrot and Turmeric

The demand for natural and healthier food products has increased dramatically in recent years due to growing consumer awareness of the impact food has on health as well as evidence of adverse effects from various ingredients, including some additives. This study evaluates the extraction method, solvent effects, precipitation, identification, purification, and lycopene, carotene, and curcumin content from turmeric, carrot, and tomato. Along-side, tomato, carrot, and turmeric samples were subjected to two different extraction and purification processes: solvent extraction for lycopene and carotene, and alkalization for curcumin. The samples were extracted and purified at room temperature (30ºC) and chilled (4ºC) for a period of three weeks. Tomato extracts had lycopene contents ranging from 0.0153 to 0.0362 mg/100g. obtained carotene content, which was then extracted using a solvent in the range of 61.43 to 81.72 mg/100g. The alkalization process produced a curcumin concentration of 91.17 to 110.41 mg/100g. Comparing the ethyl acetate extraction technique to the anti-solvent method, a greater amount of lycopene (red) and carotene (orange) precipitation was obtained. The maximum amount of curcumin precipitation obtained in lower pH solution. Lower pH is important to maintain the stability of curcumin precipitation. The experience of this research work suggested that lycopene from tomatoes, carotene from carrots, and curcumin from turmeric might be an excellent source to meet the increasing need for natural colorants.

N-Butylpyrrolidinone is an equally good solvent as N,N-dimethylformamide for microwave assisted solid phase peptide synthesis.

Solid-phase peptide synthesis (SPPS) is the prevailing method for synthesizing research peptides today. However, SPPS is associated with a significant environmental concern due to the utilization of hazardous solvents such as N,N-dimethylformamide (DMF) or N-methylpyrrolidone, which generate substantial waste. In light of this, our research endeavors to identify more environmentally friendly solvents for SPPS. In this study, we have assessed the suitability of five green solvents as alternatives to DMF in microwave assisted SPPS. The solvents evaluated include Cyrene, ethyl acetate, 1,3-dioxolane, tetrahydro-2-methylfuran, and N-Butylpyrrolidinone (NBP). Our investigation encompassed all stages of the synthesis process, from resin swelling, dissolution of reagents, culminating in the successful synthesis of five diverse peptides, including the challenging ACP 65-74, Peptide 18A, Thymosin α1, and Jung-Redemann peptide. Our findings indicate that NBP emerged as a strong contender, performing on par with DMF in all tested syntheses. Furthermore, we observed that combinations of NBP with either ethyl acetate or tetrahydro-2-methylfuran demonstrated excellent results. This research contributes to the pursuit of more sustainable and environmentally conscious practices in peptide synthesis.