Methionine Ethyl Ester Research Articles

Bioactive compounds with antifungal activity against pathogens isolated from pregnant woman: Gallesia integrifolia (garlic wood) is a promising treatment for vulvovaginal candidiasis

Ethnopharmacological relevanceThe leaves, bark, and roots of Gallesia integrifolia are consumed in folk medicine through infusion, decoction, and topical preparation by crushing because of its pharmacological properties in several peripheral system disorders, including microbial infections. The presence of various molecules in different parts of the plant likely confers this species’ fungicidal action, but scientific evidence is lacking. Vulvovaginal candidiasis mainly affects women of reproductive age. When left untreated, it can cause pregnancy complications. Currently available antifungals often cause undesirable side effects. New alternative therapeutic strategies based on medicinal plants have been proposed. AimTo investigate the antifungal activity of G. integrifolia against vulvovaginal candidiasis secretion in pregnant women. Materials and methodsAntifungal activity was determined by the minimum inhibitory concentration (MIC), determined by broth microdilution method using Candida spp (NEWP1210), C. albicans (CCCD-CC001), C. tropicalis (CCCD-CC002) standard and clinical isolates from pregnant women with vulvovaginal candidiasis. Nystatin and fluconazole were used as positive controls. The chemical composition of essential oils that were extracted from leaves, flowers, and fruits of G. integrifolia was determined by gas chromatography coupled to mass spectrometry. Reverse docking was used to suggest a possible target in Candida. Conventional docking was used to identify the most probable compound that inhibits fungal growth. ResultsA total of 24 compounds were identified, accounting for ∼99% of volatile constituents in the essential oils. Leaves of G. integrifolia contained 3,5-dithiahexanol-5,5-dioxide (40.93%), flowers contained methionine ethyl ester (46.78%), and fruits contained 2,8-dithianonane (54.01%) as the most abundant compounds. The MICs of essential oils of leaves, flowers, and fruits of G. integrifolia against standard strains of Candida spp, C. albicans, and C. tropicalis ranged from 13.01 to 625.00 μg/mL. The essential oil of flowers more effectively inhibited Candida spp. Essential oils of leaves and flowers were similar to fluconazole against C. albicans. Essential oils of flowers and fruits were similar to fluconazole against C. tropocalis. In Candida yeast species that were isolated from vaginal secretion samples from pregnant patients, the MICs of leaves and flowers ranged from 52.08 to 5000.00 μg/mL. The essential oil of leaves (277.77 μg/mL) was the most active against C. albicans. No significant differences were found between the essential oils of leaves and flowers against C. glabrata. Docking simulations suggested that phytol in leaves and flowers was responsible for the antimicrobial effect. ConclusionThe present results suggest the potential therapeutic use of G. integrifolia, especially its leaves and flowers, against Candida and vulvovaginal candidiasis.

Insecticidal activity ofGallesia integrifolia (Phytolaccaceae) essential oil

This study evaluated the insecticidal activity of Gallesia integrifoliaessential oil from fruits, leaves, and flowers against Aedes aegyptilarvae and pupae. The essential oil was obtained by hydrodistillation and characterized by gas chromatography-mass spectrometry. Sulfur compounds represented 95 to 99% of the essential oil from fruits, leaves, and flowers. Essential oil major compounds were 2,8-dithianonane (52.6%) in fruits, 3,5-dithiahexanol-5,5-dioxide (38.9%) in leaves, and methionine ethyl ester (45.3%) in flowers. The essential oils showed high activity against larvae, and low for pupae withLC99.9of 5.87 and 1476.67μg/mL from fruits; 0.0096 and 348.33 μg/mL from leaves and 0.021and 342.84 μg/mL from flowers, respectively. The main compound with insecticide activity is probably n-ethyl-1,3-dithioisoindole, from isoindole organothiophosphate class, found in greater amount in flower and leaf essential oil. The great insecticide activity of G. integrifoliaessential oil suggests that this product is a natural insecticide.

Biogenic amino acid methionine-based corrosion inhibitors of mild steel in acidic media

N, N-Diallyl methionine ethyl ester hydrochloride 5 underwent alternating copolymerization with SO2 via the Butler cyclopolymerization protocol in dimethyl sulfoxide (DMSO) to give water-soluble cycloterpolymer 6 with a ∼1:1 molar ratio of sulfide and sulfoxide groups as a result of oxygen transfer from DMSO. Half of the sulfide groups in 6, upon oxidation with H2O2, afforded polymer sulfoxide 7 and polymer sulfone 8. The solution properties of these polymers were determined via a viscometric technique. The thermal stability of these polymers was determined by thermogravimetric analysis. The inhibition efficiency obtained from gravimetric mass loss, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques agreed well with each other. The corrosion efficiencies increase with increasing concentration of the polymers. At a polymer concentration of 175 μM, the maximum inhibition efficiency of copolymer compounds 6–8 was determined to be 92%, 97%, and 95%, respectively. The synthesized polymer compounds acted as mixed-type inhibitors. Polymer compound 7 adsorbed onto the metal surface via chemisorption and physisorption and obeyed Langmuir, Temkin, and Freundlich adsorption isotherms. Analyses by X-ray photoelectron spectroscopy and scanning electron microscopy-energy-dispersive X-ray spectroscopy indicated that the adsorbed polymers formed a thin film on the metal surface and prevented further corrosive attack.

Synthesis, single crystal X-ray structures of ONNO, ONN and ONS-Pd(II) complexes and their anticancer activities

Abstract Pd(salicylaldimine)2 (ONNO-Pd)(C1 and C2), Pd(salicylaldimine)Cl (ONN-Pd) (C3) and methionine derived ONS donor ligand based (ONS-Pd) Pd(salicylaldimine methionine ethyl ester)Cl (C4) complexes were prepared and structurally characterized by 1H, 13C NMR spectroscopy, high-resolution electrospray mass spectrometry and single crystal X-ray analyses (C1, C2 and C4). In C1 and C2 two ON-donor salicylaldimine ligands completed four coordinates of Pd(II) while in C4 these coordinate were completed by ONS-donor atoms of salicylaldimine and one Cl ancillary ligand. In vitro cytotoxicity assays were performed for these complexes in non-small cell lung (A549) and hepatocellular (HepG2) cancer cells. MTT assay showed that these Pd complexes suppress cancer cells viability and inhibited cell growth in dose and time-dependent manner. Cell cycle analysis was performed in A549 cells. To check the interaction of these complexes with DNA gel electrophoresis study was performed that revealed stronger binding affinity of these complexes with DNA.

Inhibition of mild steel corrosion in hydrochloric acid medium by polymeric inhibitors containing residues of essential amino acid methionine

Ethyl ester hydrochloride of amino acid l-methionine 1 was converted to cationic monomers N,N-diallyl methionine ethyl ester hydrochloride 2 and hydrochloride salt of N,N-diallylmethionine 3. Cationic monomers 2 and 3 underwent alternate copolymerization with SO2 in dimethyl sulfoxide to give terpolymers 4 and 5, respectively, both having ≈ 1:1 ratio of sulfide and sulfoxide motifs owing to O transfer from dimethyl sulfoxide to the S. The sulfide groups in 5 have been oxidized with H2O2 to give polymer sulfoxide 6. In the presence of a small concentration of 35.2 µM (~ 11 ± 1 ppm) of each of the polymers 4, 5 and 6, the inhibition efficiency against mild steel corrosion in 1.0 M HCl at 60 °C was determined to be 90.8, 98.7 and 93.0%, respectively. The inhibition efficiency obtained from gravimetric weight loss was corroborated by the findings of potentiodynamic polarization and electrochemical impedance spectroscopy methods. Adsorption of polymer compounds onto the mild steel surface followed a mixture of chemisorption and physisorption processes and obeyed Langmuir, Temkin and Freundlich adsorption isotherms. The X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy techniques further confirmed that the synthesized compounds formed a protective film onto the metal surface and prove it against further corrosion attack.

A novel cyclopolymer containing residues of essential amino acid methionine: synthesis and application

Ethyl ester hydrochloride of essential amino acid methionine upon treatment with allyl bromide affords N,N-diallyl methionine ethyl ester (I) which after treatment with HCl leads to a novel monomer N,N-diallyl methionine ethyl ester hydrochloride (II). Monomer II is cyclocopolymerized with sulfur dioxide in acetone or ethanol to obtain the corresponding water-insoluble alternate cocyclopolymer III (i.e., II-alt-SO2), while quite surprisingly, the polymerization carried out in dimethyl sulfoxide (DMSO) affords a water-soluble terpolymer IV: (II{in sulfide form}-alt-SO2)-ran-(II{in sulfoxide form}-alt-SO2) in which half of the sulfide groups has been oxidized to sulfoxide groups via oxygen exchange with solvent DMSO. Polymer IV containing the residues of methionine demonstrates superior inhibition of mild steel corrosion in 1 M HCl at 60 °C; inhibition efficiency (IE) of 99 % is achieved at a concentration of 25 ppm. At a meager concentration of 1.25 ppm, the polymer leads to an astonishing IE of 93 %, while its corresponding monomer II achieves an IE of 31 % at the same concentration. The adsorption of polymer IV on the metal surface was found to obey the Langmuir adsorption isotherm. The high negative $$\Delta G^\circ_{\text{ads}}$$ value of −57.7 kJ mol−1 ensured the favorability of the adsorption process and indicated the prevalence of both electrostatic adsorption and chemisorption. The polymer having multiple adsorption sites gave superior protection of mild steel surface than methionine or its ester derivative I or the monomeric counterpart II. The essential amino acid methionine has been converted into diallylamine salt which undergoes cyclocopolymerization with SO2 to give a novel polymer in which 50 % of the sulfide group is oxidized to sulfoxide via oxygen exchange with dimethyl sulfoxide. The polymer (at a concentration of 1.25 ppm) demonstrates a superb inhibition efficiency (IE) of 93 % of mild steel corrosion in 1 M HCl at 60 °C, while at 100 ppm it achieves an IE of 99 %.

Synthesis and preparation of nanoparticles composed of amphiphilic poly(γ-glutamic acid) with different hydrophobic side chains and their potential of membrane disruptive activity

In the development of nanoparticle-based vaccine adjuvants, the interaction between nanoparticles (NPs) and the cells is a key factor. To control them, we focused on the relationship between the hydrophobicity of the side chains and the cell membrane. In this study, amphiphilic poly(γ-glutamic acid) (γ-PGA), using various types of hydrophobic side chains, was synthesized and used to prepare NPs for evaluating the membrane disruptive activity. When leucine ethyl ester (Leu), methionine ethyl ester (Met), or tryptophan ethyl ester (Trp) was grafted, each polymer formed monodispersed NPs at physiological conditions. Significantly, NPs composed of Leu and Trp showed a membrane disruptive activity at the endosomal environment (pH 5–6.5), while NPs composed of Met did not show. This might be due to the weak hydrophobicity of Met compared to that of Leu and Trp, which demonstrated that the interaction between NPs and cells could be controlled by designing the polymer compositions.

Synthesis and Characterization of Methionine- and Cysteine-Substituted Phosphazenes

The preparation of phosphazenes that possess reversible cross-linking groups to control mechanical stability and hydrolysis has been accomplished using cysteine and methionine amino acid side groups. Small molecule models and linear polymeric phosphazenes that contain methionine ethyl ester and cysteine ethyl disulfide ethyl ester side groups were synthesized. Protection of the free thiol groups was carried out to circumvent unwanted cross-linking of the phosphazenes through the cysteine ethyl ester N- and S-termini. Cyclic trimeric cysteine ethyl disulfide ethyl ester model compounds were deprotected by S−S bond cleavage using β-mercaptoethanol, dithiothreitol (DTT), and zinc in aqueous hydrochloric acid. For the high polymeric derivatives, the extent of S−S bond cleavage varied depending on the deprotection method used. With the exception of the Zn/HCl method, the resultant deprotected polymers were soluble in common organic solvents and underwent minimal chain cleavage during the reaction sequence. The...

Electrochemical studies of the corrosion inhibition of methionine ethyl ester on iron in citric-chloride solution

The effect of methionine ethyl ester (MetOC2H5), a non-toxic compound on the corrosion of iron in citric-chloride solution at pH = 5, has been investigated by various corrosion monitoring techniques. Results obtained reveal that this compound is a very good inhibitor. Potentiodynamic polarization studies show that MetOC2H5 is a mixed-type inhibitor and that it acts on the cathodic reaction without changing the mechanism of hydrogen evolution. Variation in impedance parameters (Rt and Cdl) are indicative of adsorption of MetOC2H5 on the metal surface. The adsorption of this product on the iron surface obeys a Temkin adsorption isotherm. The effect of temperature indicates that inhibition efficiency of MetOC2H5 slightly changes with increasing temperature in the range of 30-60 °C.

A thioester analogue of an amino acetylenic aldehyde is a suicide inhibitor of aldehyde dehydrogenase and an inducer of apoptosis in mouse lymphoid cells overexpressing the bcl2 gene.

We have previously shown that methional, CH3SCH2CH2CHO, an endogeneous cellular aldehyderived by the oxidative decarboxylation of 4-methylthio-2-oxobutanoic acid (B), an intermediate in the methionine salvage pathway is a potent inducer of apoptosis when added to cultures of mouse lymphoid cells BAF3 bo (Quash et al., 1995). MTOB a00 μM was also capable of alleviating the methionine dependence shown by transfed cells (Ogier et al., 1993) because of its ready transamination to methionine, with gamine as amine donor (Backlund et al., 1982). Further, the inhibition of this MTOB transaminase with novel transition state inhibitors such as methionine-ethyl ester- pyridoxal induced apoptosis in BAF3 bo cells but not in BAF3 bcl2 which had been trans- fected with the human bcl2 gene (Roch et al., 1996). When the reasons for this refractory behaviour of BAF3 bcl2 were investigated using[14C] MTOB it was found that the production of [14methional from [14C] MTOB was reduced by 50% in BAF3 bcl2 and that even the direct addition of 600μM methional could not induce apoptosis in BAF3 bcl2 (Roch and al, 19 Methional is itself further metabolised intracellularly [Figure 1] by 3 pathways: reduction by aldehyde reductase (ALR) to methionol, oxidation by aldehyde dehydro- genaseLDH1) to methyl thiopropionic acid and β-hydroxylation to malondialdehyde. We therefore tried to see whether the inhibition of the reductase or the dehydrogenase would uce apoptosis in methional treated BAF3 bcl2 cells. Using quercitin as an inhibitor of ALR increase in apotosis was observed in BAF3 bcl2, but this result is to be interpreted with caution as quercitin also induces DNA strand breaks directly.With disulfiram as an ibitor of ALDH a small increase was seen but experimentation could be carried out only with low concentrations (< 100μM) due to the intrinsic toxicity of this compound. It was therefore clear that more specific inhibitors of ALDH were required to try to determine if ALDH played a role in the resistance to the apoptosis-inducing activity of methio.KeywordsAldehyde DehydrogenaseALDH ActivityThioctic AcidAldehyde ReductaseDiethyl AcetalThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

REDUCTION OF ALLERGENICITY AND INCREASING THE BIOLOGICAL VALUE OF BUFFALO'S MILK PROTEINS BY ENZYMATIC MODIFICATION

Buffalo milk proteins were covalently enriched with methionine (Met) during the enzymatic peptide modification (EPM) process. The maximal Met-enrichment occurred when the α-chymotryptic hydrolysate of buffalo's milk proteins was treated with methionine ethyl ester in the presence of α-chymotrypsin during the EPM. Methionine content of this product was more than three times (5.4%) higher than that of the original buffalo milk protein (1.5%). The electrophoretic patterns of the modified proteins showed that the enzymatic reaction was mainly characterized by transpeptidation. Molecular masses of the modified protein fractions were influenced by the concentration of L-methionine ethyl esters in the reaction mixture during the EPM. EPM products from the buffalo milk protein hydrolysates with α-chymotrypsin and trypsin or with pepsin and trypsin showed low allergenic activities compared with those when buffalo milk proteins were hydrolyzed with α-chymotrypsin or with pepsin alone.

Preparations ofN, N?-ethylene-bridged dipeptides(eXX) constructed from (S)-methionine, -tryptophan, -tyrosine and-N(?)-benzyloxycarbonyllysine through acid-catalyzed cyclization

N, N'-Ethylene-bridged bis-(S)-methionine[(2S, 7S)-2, 7-bis(2-methyl-thioethyl)-3,6-diazaoctanedioic acid] derived from (S)-methionine and 1,2-dibromoethane was cyclized and esterified simultaneously in boiling ethanol in the presence of an appropriate amount of strong acid such asp-toluenesulfonic acid, affording a cyclic compound,N, N'-ethylene-bridged (S)-methionyl-(S)-methionine ethyl ester {ethyl(2S, 3'S)-4-(methylthio)-2-[2'-oxo-3'-(2-methylthioethyl)-1'-piperazinyl] butanoate}, exclusively in 80-90% yields. It was also found that, by applying this method, 70-80% yields of the otherN, N'-ethylenebridged dipeptides containing (S)-tryptophan, -tyrosine and -N(ɛ)-benzyloxycarbonyllysine were obtained.

RADIOACTIVE METHIONINE INCORPORATION INTO PEPTIDE CHAINS BY ENZYMATIC MODIFICATION

Enzymatic peptide modification was carried out using L-methionine-S-methyl-14C methyl ester hydrochloride and L-3H methionine ethyl ester hydrochloride in the reaction mixture. The experimental results revealed that part of the L-methionine-S-methyl-14 C methyl ester was bound as methionine to enzymatic hydrolysates of casein and serum albumin in the presence of α-chymotrypsin, interestingly in the highest molecular weight fraction of the product protein. A maximum curve was found to describe the relation between α -chymotrypsin-induced incorporation of methionine and the ratio of L-3H methionine ethyl ester to protein hydrolysate. The covalent nature of amino acid incorporation was supported by SDS polyacrylamide gel electrophoresis in the presence of urea. The isoelectric focusing patterns of the products indicate that transpeptidation plays an essential role in the EPM reaction. These experimental findings suggest that enzymatic peptide modification is a suitable method for the production of proteins of designed amino acid composition.

Amide‐Bond Syntheses Catalyzed by Penicillin Acylase

AbstractThe enzymatic synthesis of amide bonds catalyzed by penicillin acylase is investigated both in H2O solution and in organic solvents containing reverse micelles. The specificity of the reaction is rather high on the side of the acyl component, practically only phenylacetic acid gives sizeable yields. On the contrary, a variety of amino‐acid esters, dipeptides, and tripeptides can be used as amino component, e.g., serine methyl ester, methionine ethyl ester, tyrosine ethyl ester, Gly–Asp, Ala–Tyr, Gly–Tyr–Gly etc. However, Many other amino‐acid residues do not react, and the possible reasons for this are discussed. Yields varyin rang the 10–80%. A. systematic study to optimize yields by varying the solvent composition is presented for one model reaction. The enzyme is also able to couple certain D‐amino‐acid residues (e.g. D‐methionine ethyl ester or Gly‐D‐Asp) though at lower rate. Reverse micelles formed by the cationic surfactant cetyltrimethylammonium bromide (CTAB) in CHCl3/isooctane are used to host penicillin acylase and to perform amide synthesis in which the product is perferentially soluble in the organic solvent mixture. The reaction is studied as a function of pH and certain micellar parameters, e. g. wo (wo = [H2O]/[CTAB]). A new membrane enzyme reactor is utilized to separate the product from the enzyme‐containing micelles. The adavantges and the limits of this approach are discussed.

N-(Indol-3-ylglyoxylyl)methionine derivatives: preparation and gastric anti-secretory activity

The authors describe the synthesis of several N-(indol-3-ylglyoxylyl)methionine derivatives. The target compounds were prepared starting from substituted indoleglyoxylyl chlorides and methionine ethyl ester. Some of them were tested for their gastric anti-secretory activity. Among these compounds, the N-(5-chloroindol-3-ylglyoxylyl)methionine Ve was the most active, being quite comparable to cimetidine.

Free radical one-electron versus hydroxyl radical-induced oxidation. Reaction of trichloromethylperoxyl radicals with simple and substituted aliphatic sulphides in aqueous solution

One-electron oxidation of organic sulphides leading to sulphur-centred radical cations, R2S+˙, can conveniently be initiated by CCl3O2˙ radicals. Absolute rate constants have been measured for the reaction of CCl3O2˙ with dimethyl sulphide, 2-(ethylthio)ethanol, and methionine to be 1.8 × 108, 4 × 107, and 2.9 × 107 mol–1 dm3 s–1, respectively. Oxidation of dimethyl sulphide and methionine by the halothane-derived CF3CHClO2˙ radical occurs with absolute rate constants of k 6 × 106 and 1.4 × 106 mol–1 dm3s–1, respectively. The R2S+˙ generally equilibrates according to R2S+˙+ R2S ⇌(R2S ∴ SR2)+ to yield sulphur-centred three-electron-bonded radical cations. Amino-substituted sulphides such as 3-(methylthio)propylamine, methionine, and methionine ethyl ester also stabilize as intramolecularly formed S ∴ N three-electron-bonded radical cations. This competing reaction route requires a free electron pair at nitrogen, i.e. an unprotonated amino group, and steric assistance by five- or six-membered ring structures. The pH profiles of S ∴ S and S ∴ N bond formation are significantly different in the oxidation of the amino-substituted sulphides by one-electron oxidants from those for the ˙OH radical-induced process. The underlying mechanisms are compared and discussed.

S∴N and S∴O three-electron-bonded radicals and radical cations in aqueous solutions

Intramolecularly formed S∴N three-electron-bonded radical cations have been identified as transient intermediates in the ′OH radical-induced oxidation of 3-(methylthio)propylamine, methionine, and methionine ethyl ester. A similarly bonded radical is also indicated in the reduction of dehydromethionine by hydrated electrons. Intramolecular S∴O-bonded intermediates are suggested to be formed in the ˙OH-induced oxidation of 4-(methylthio)butyric acid and S-methylcysteine. All these three-electron-bonded species exhibit optical absorptions with maxima in the 380–400 nm range. The observable S∴O-bonded transient from S-methylcysteine is presumed to be protonated at oxygen. Favourable steric structures, particularly five-membered rings, significantly increase the probability of formation and the overall stability of a particular three-electron bond. Under comparable conditions, i.e. structure, substituents, consecutive chemistry, etc., the S∴O bond appears to be considerably weaker than corresponding S∴N and S∴S bonds.

Use of transglutaminase. Reversible blocking of amino groups in substrate proteins for a high yield of specific products.

Transglutaminase catalyzes an acyl-transfer reaction in which the y-carboxyamide groups of pep tide-bound glutaminyl residues are the acyl donors. Primary amino groups in a variety of compounds act as acyl acceptors with the subsequent formation of the monosubstituted γ-amide of the peptide-bound glutamic acid. When one wants to bind a desired amino compound into glutamine residues in a protein using this enzyme, concurrent generation of intra- and intermolecular ∊-(γ-glutamyl)lysine crosslinks of the protein lowers the binding efficiency because the reactive glutamine residues are consumed by the crosslinking. Maleylation of amino groups in proteins was attempted with maleic anhydride in order to suppress this unfavorable crosslink formation. Maleylation of caseins, mainly αs1-casein, increased the rate and the extent of transglutaminase-catalyzed incorporation of amino compounds such as putrescine, methionine ethyl ester, and NAD+ analog into the modified proteins. Generation of intermolecular crosslink...

Studies on methionine derivatives as possible sources of protected methionine in ruminant rations.

AbstractN‐Oleoyl‐D,L‐methionine, D,L‐methionine ethyl ester HCI and the methyl ester of methionine hydroxy analogue were examined for their ability to produce methyl mercaptan in the rumen of sheep. Results indicated that all derivatives were more stable than methionine. The derivatives were then examined for their ability, when fed in the diet, to increase the plasma methionine concentration of sheep. Methionine ethyl ester caused a marked rise. Further results suggested that while some of the methionine ester escaped ruminal degradation, it also passed through the rumen wall. The compound was found to be rapidly hydrolysed in the liver to yield methionine. The effects of the other derivatives tested on plasma methionine concentrations were small.