4-Methoxybenzoic acid

Evaluation of the Behavior of Phenolic Compounds and Steviol Glycosides of Sonicated Strawberry Juice Sweetened with Stevia (Stevia rebaudiana Bertoni).[Pubmed:30934766]

Molecules. 2019 Mar 27;24(7). pii: molecules24071202.

In this study, the influence of stevia addition and sonication processing parameters on the phenolic content and profile as well as the steviol glycosides of strawberry juice-based samples was investigated. For this purpose, three matrices-control samples of strawberry juices without green stevia powder (CS), strawberry juices with green stevia powder (JGSP), and sonicated juices with green stevia powder (SJGSP)-were prepared. For sonication purposes, different conditions regarding probe diameters (7 mm and 22 mm), amplitudes (50%, 75%, and 100%), and time (15 min, 20 min, and 25 min) were tested. The results that were obtained upon the measurement of the total phenolic content, total flavonoids, steviol glycosides, and antioxidant capacity showed significant differences according to the matrices evaluated, obtaining overall higher values in the samples with stevia added. Moreover, when sonication was evaluated, it was found that a higher amplitude (100%), a larger probe diameter (22 mm), and a longer sonication period (25 min) led to higher values. Flavones such as luteolin and apigenin were identified and quantified in JGSP and SJGSP, while they were not found in CS. Besides these phenolic compounds, kaempferol, quercetin, pyrogallic acid, 4-methylcatechol, and 4-Methoxybenzoic acid were also identified and quantified. Similarly to the total phenolic compounds, total flavonoids, and total antioxidant capacity, an increased amount of these compounds was found in SJGSP, especially after using the most intense sonication conditions. Therefore, the use of sonication together with stevia added could be a useful tool to preserve strawberry juices, increasing at the same time the sweetness and the antioxidant value of the beverages.

Synthesis, in vitro and in silico studies of S-alkylated 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole-3-thiols as cholinesterase inhibitors.[Pubmed:30587482]

Pak J Pharm Sci. 2018 Nov;31(6 (Supplementary):2697-2708.

The research was aimed to unravel the enzymatic potential of sequentially transformed new triazoles by chemically converting 4-Methoxybenzoic acid via Fischer's esterification to 4-methoxybenzoate which underwent hydrazinolysis and the corresponding hydrazide (1) was cyclized with phenyl isothiocyanate (2) via 2-(4-methoxybenzoyl)-N-phenylhydrazinecarbothioamide (3); an intermediate to 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazol-3-thiol (4). The electrophiles; alkyl halides 5(a-g) were further reacted with nucleophilic S-atom to attain a series of S-alkylated 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole-3-thiols 6(a-g). Characterization of synthesized compounds was accomplished by contemporary spectral techniques such as FT-IR, 1H-NMR, 13C-NMR and EI-MS. Excellent cholinesterase inhibitory potential was portrayed by 3-(n-heptylthio)-5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole; 6g against AChE (IC50; 38.35+/-0.62muM) and BChE (IC50; 147.75+/-0.67muM) enzymes. Eserine (IC50; 0.04+/-0.01muM) was used as reference standard. Anti-proliferative activity results ascertained that derivative encompassing long straight chain substituted at S-atom of the moiety was the most potent with 4.96 % cell viability (6g) at 25muM and with 2.41% cell viability at 50muMamong library of synthesized derivatives. In silico analysis also substantiated the bioactivity statistics.

Ammonia Synthesis from a Pincer Ruthenium Nitride via Metal-Ligand Cooperative Proton-Coupled Electron Transfer.[Pubmed:28383261]

J Am Chem Soc. 2017 Apr 19;139(15):5305-5308.

The conversion of metal nitride complexes to ammonia may be essential to dinitrogen fixation. We report a new reduction pathway that utilizes ligating acids and metal-ligand cooperation to effect this conversion without external reductants. Weak acids such as 4-Methoxybenzoic acid and 2-pyridone react with nitride complex [(H-PNP)RuN](+) (H-PNP = HN(CH2CH2P(t)Bu2)2) to generate octahedral ammine complexes that are kappa(2)-chelated by the conjugate base. Experimental and computational mechanistic studies reveal the important role of Lewis basic sites proximal to the acidic proton in facilitating protonation of the nitride. The subsequent reduction to ammonia is enabled by intramolecular 2H(+)/2e(-) proton-coupled electron transfer from the saturated pincer ligand backbone.

Temperature-induced first-order displacive phase transition of isonicotinamide-4-methoxybenzoic acid co-crystal.[Pubmed:28362293]

Acta Crystallogr B Struct Sci Cryst Eng Mater. 2017 Apr 1;73(Pt 2):285-295.

Isonicotinamide-4-Methoxybenzoic acid co-crystal (1), C6H6N2O.C8H8O3, is formed through slow evaporation from methanol solution and it undergoes a first-order isosymmetry (monoclinic I2/a <--> monoclinic I2/a) structural phase transition at Tc = 142.5 (5) K, which has been confirmed by an abrupt jump of crystallographic interaxial angle beta from variable-temperature single-crystal XRD and small heat hysteresis (6.25 K) in differential scanning calorimetry measurement. The three-dimensional X-ray crystal structures of (1) at the low-temperature phase (LTP) (100, 140 and 142 K) and the high-temperature phase (HTP) (143, 150, 200, 250 and 300 K) were solved and refined as a simple non-disordered model with final R[F(2) > 2sigma(F(2))] approximately 0.05. The asymmetric unit of (1) consists of crystallographically independent 4-Methoxybenzoic acid (A) and isonicotinamide (B) molecules in both enantiotropic phases. Molecule A adopts a `near-hydroxyl' conformation in which the hydroxyl and methoxy groups are positioned on the same side. Both `near-hydroxyl' and `near-carbonyl' molecular conformations possess minimum conformational energies with an energy difference of < 0.15 kJ mol(-1) from a potential energy surface scan. In the crystal, molecules are joined into linear ABBA arrays by intermolecular N-H...O and O-H...N hydrogen bonds which were preserved in both phases. However, these ABBA arrays are displaced from planarity upon LTP-to-HTP transition and the changes in inter-array interactions are observed in two-dimensional fingerprint plots of their Hirshfeld surfaces. The PIXEL energies of each molecular pair in both phases were calculated to investigate the difference in intermolecular interaction energies before and after the displacement of ABBA arrays from planarity, which directly leads to the single-crystal-to-single-crystal phase transition of (1).

[Ethyl Acetate-Soluble Chemical Constituents from Callicarpa kwangtungensis (II)].[Pubmed:27356382]

Zhong Yao Cai. 2015 Nov;38(11):2314-7.

OBJECTIVE: To study the ethyl acetate-soluble chemical constituents of Callicarpa kwangtungensis. METHODS: The chemical constituents were isolated by column chromatography on silica gel, Sephadex LH-20 and MPLC. Their chemical structures were elucidated on the basis of special analysis. RESULTS: Eleven compounds were isolated from the ethyl acetate-soluble part of Callicarpa kwangtungensis, whose structures were elucidated as 4-Methoxybenzoic acid (1), 3,4-dihydroxybenzoic acid (2), 4-hydroxy cinnamic acid(3), phenyl-beta-D-glucopyranoside (4), 3,4,5-trimethoxyphenyl-beta-D-glucopyranoside (5), 2alpha,3beta,22beta,23-tetrahydroxyursolic-12-en-28-oic acid (6), 2alpha,3beta,6beta,19alpha-tetrahydroxy-urs-12-en-28-O-beta-D-glucopyranoside (7), 2beta,3beta,6beta,16alpha-tetrahydroxy-olean-12-en-28-O-beta-D-glucopyranoside (8), (3S, 6E, 10R)-10-beta-D-glucopyranosyloxy-3,11-dihydroxy-3,7,11-trimethyldodeca-1,6-diene (9), icariside C5(10), and (2E, 6E)-10-beta-D-glucopyranosyl-1, 11-dihydroxy-3, 7, 11-trimethyldodeca-2,6-diene (11). CONCLUSION: Compounds 4 - 11are isolated from Callicarpa genus for the first time, compounds 1 - 3 are isolated from this plant for the first time.

[Chemical Constituents of the Aerial Parts from Plumbago zeylanica].[Pubmed:30203952]

Zhong Yao Cai. 2016 Jul;39(7):1541-4.

Objective: To study the anti-oxidative constituents of the aerial parts of Plumbago zeylanica. Methods: The ethanol extract of Plumbago zeylanica was separated and purified by various chromatographic techniques. On the basis of various spectroscopic data, the structures of isolated compounds were elucidated. ABTS+radical scavenging were carried out in antioxidant activity evaluation of the isolated compounds. Results: Eleven compounds were isolated and identified as cis-isoshinanolone-4-O-beta-D-glucopyranoside( 1),tachioside( 2),2,6-dimethoxy-p-hydroquinone-1-O-beta-D-glucopyranoside( 3),3-( beta-D-glucopyranosyloxy)-4-Methoxybenzoic acid( 4),3'-O-beta-D-glucopyranosyloxy-plumbagic acid( 5),3'-O-beta-D-glucopyranosyloxy-plumbagic acid methyl ester( 6),plumbagic acid( 7),plumbagine A( 8),plumbagine C( 9),syringate-4-O-beta-D-glucopyranoside( 10) and 2-methyl-5-hydroxychromone( 11). Compounds 2,3,and5 displayed significant scavenging effect on ABTS+. Conclusion: Compounds 1 ~ 4,10,11 are obtained from this plant for the first time. Compounds 2,3,and 5 show significant anti-oxidative effects.

The importance of the benzoic acid carboxylate moiety for substrate recognition by CYP199A4 from Rhodopseudomonas palustris HaA2.[Pubmed:26969786]

Biochim Biophys Acta. 2016 Jun;1864(6):667-675.

BACKGROUND: The cytochrome P450 enzyme CYP199A4 can efficiently demethylate 4-Methoxybenzoic acid. The substrate is positioned in the enzyme active site with the methoxy group ideally positioned for demethylation. This occurs through interactions of hydrophobic benzene ring with aromatic phenylalanine residues and the charged carboxylate group with polar and basic amino acids. METHODS: In vitro substrate binding and kinetic turnover assays coupled with HPLC and GC-MS analysis and whole-cell oxidation turnovers. RESULTS: Modification of the carboxylate group to an amide or aldehyde resulted in substrate binding, as judged by the almost total shift of the spin state to the high-spin form, but binding was three orders of magnitude weaker. Changing the carboxylate to phenol alcohol, ketone, ester and nitro groups and boronic, sulfinic and sulfonic acids resulted in a dramatic reduction in the binding affinity. Even phenylacetic acids were mediocre substrates for CYP199A4, despite maintaining a carboxylate group. The weaker binding of all of these substrates results in lower levels of turnover activity and product formation compared to 4-Methoxybenzoic acid. CONCLUSION: Substrate binding to CYP199A4 is tightly regulated by interactions between the 4-Methoxybenzoic acid and the amino acids in the active site. The benzoic acid carboxylate moiety is critical for optimal substrate binding and turnover activity with CYP199A4. GENERAL SIGNIFICANCE: An understanding of how the CYP199A4 enzyme has evolved to be highly selective for para-substituted benzoic acids. This provides valuable insight into how other, as yet structurally uncharacterised, monooxygenase enzymes may bind benzoic acid substrates.

Uncommon secondary metabolites from Etlingera pavieana rhizomes.[Pubmed:26901239]

Nat Prod Res. 2016 Oct;30(19):2215-9.

From the rhizomes of Etlingera pavieana (Pierre ex Gagnep.) R.M. Sm., four phenylpropens, (E)-3-(4-methoxyphenyl)prop-2-en-1-amine (1), (E)-4-methoxycinamaldehyde (2), (E)-4-methoxycinamic acid (3) and (E)-1-methoxy-4-(3-methoxyprop-1-enyl)benzene (4), together with two other compounds, (E)-((E)-3-(4-methoxyphenyl)allyl)3-(4-hydroxyphenyl)acrylate (5) and 4-Methoxybenzoic acid (6) were isolated. This is the first report on the presence of all compounds in Etlingera. Compounds 1 and 5 have been previously synthesised, but this is the first report of their isolation from a natural source. Compound 5 exhibited weak activity against Mycobacterium tuberculosis with MIC 50.00 mug/mL and cytotoxic activity against the KB, MCF7 and NCI-H187 cells with IC50 values of 25.11, 20.16 and 34.83 mug/mL, respectively.

[Chemical Constituents from Mallotus paniculatus (II)].[Pubmed:26672344]

Zhong Yao Cai. 2015 Apr;38(4):764-5.

OBJECTIVE: To study the chemical constituents of Mallotus paniculaus radix. METHODS: The compounds were isolated with column chromatography. The chemical structures were identified by spectral and spectroscopic technology. RESULTS: Seven compounds were isolated from the n-BuOH extract and identified as scopoletin(1), isoscopletin(2), erythordiol(3), apigenin(4), 4-Methoxybenzoic acid(5), acetylaleuritolic acid(6) and beta-daucosterol (7). CONCLUSION: compounds 2 - 6 are isolated from this plant for the first time.

Nanoimprinted Patterned Pillar Substrates for Surface-Enhanced Raman Scattering Applications.[Pubmed:26402032]

ACS Appl Mater Interfaces. 2015 Oct 7;7(39):22106-13.

A pragmatic method to deposit silver nanoparticles on polydopamine-coated nanoimprinted pillars for use as surface-enhanced Raman scattering (SERS) substrates was developed. Pillar arrays consisting of poly(methyl methacrylate) (PMMA) that ranged in diameter from 300 to 500 nm were fabricated using nanoimprint lithography. The arrays had periodicities from 0.6 to 4.0 mum. A polydopamine layer was coated on the pillars in order to facilitate the reduction of silver ions to create silver nucleation sites during the electroless deposition of sliver nanoparticles. The size and density of silver nanoparticles were controlled by adjusting the growth time for the optimization of the SERS performance. The size of the surface-adhered nanoparticles ranged between 75 and 175 nm, and the average particle density was approximately 30 particles per mum(2). These functionalized arrays had a high sensitivity and excellent signal reproducibility for the SERS-based detection of 4-Methoxybenzoic acid. The substrates were also able to allow the SERS-based differentiation of three types of bacteriophages (lambda, T3, and T7).

Cerium(IV) Hexanuclear Clusters from Cerium(III) Precursors: Molecular Models for Oxidative Growth of Ceria Nanoparticles.[Pubmed:26236034]

Chemistry. 2015 Sep 14;21(38):13454-61.

Reactions of cerium(III) nitrate, Ce(NO3 )3 6 H2 O, with different carboxylic acids, such as pivalic acid, benzoic acid, and 4-Methoxybenzoic acid, in the presence of a tridentate N,N,N-donor ligand, diethylenetriamine (L(1) ), under aerobic conditions yielded the corresponding cerium hexamers Ce6 O8 (O2 CtBu)8 (L(1) )4 (1), Ce6 O8 (O2 CC6 H5 )8 (L(1) )4 (2), and Ce6 O8 (O2 CC6 H4 -4-OCH3 )8 (L(1) )4 (3). Hexamers 1, 2, and 3 contain the same octahedral Ce(IV) 6 O8 core, in which all interstitial oxygen atoms are connected by mu3 -oxo bridging ligands. In contrast, treatment of the Ce(IV) precursor (NH4 )2 Ce(NO3 )6 (CAN) with pivalic acid and the ligand L(1) under the same conditions afforded Ce6 O4 (OH)4 (O2 CtBu)12 (L(1) )2 (4), exhibiting a deformed octahedral Ce(IV) 6 O4 (OH)4 core containing mu3 -oxo and mu3 -hydroxo moieties in defined positions. In contrast to the formation of 1-3, the use of N-methyldiethanolamine (L) in the reaction with Ce(NO3 )3 6 H2 O and pivalic acid afforded a previously reported Ce(III) dinuclear cluster, Ce2 (O2 CtBu)6 L2 , even in the presence of dioxygen. ESI-MS analysis of the reaction mixture clearly indicated the importance of the ligand L(1) in promoting oxidation of the Ce(III) aggregates, [Cen (O2 CtBu)3n (L(1) )2 ], which is necessary for the formation of Ce(IV) hexamers.

Structure-Activity Relationships of Antimicrobial Gallic Acid Derivatives from Pomegranate and Acacia Fruit Extracts against Potato Bacterial Wilt Pathogen.[Pubmed:26080741]

Chem Biodivers. 2015 Jun;12(6):955-62.

Bacterial wilts of potato, tomato, pepper, and or eggplant caused by Ralstonia solanacearum are among the most serious plant diseases worldwide. In this study, the issue of developing bactericidal agents from natural sources against R. solanacearum derived from plant extracts was addressed. Extracts prepared from 25 plant species with antiseptic relevance in Egyptian folk medicine were screened for their antimicrobial properties against the potato pathogen R. solancearum by using the disc-zone inhibition assay and microtitre plate dilution method. Plants exhibiting notable antimicrobial activities against the tested pathogen include extracts from Acacia arabica and Punica granatum. Bioactivity-guided fractionation of A. arabica and P. granatum resulted in the isolation of bioactive compounds 3,5-dihydroxy-4-Methoxybenzoic acid and gallic acid, in addition to epicatechin. All isolates displayed significant antimicrobial activities against R. solanacearum (MIC values 0.5-9 mg/ml), with 3,5-dihydroxy-4-Methoxybenzoic acid being the most effective one with a MIC value of 0.47 mg/ml. We further performed a structure-activity relationship (SAR) study for the inhibition of R. solanacearum growth by ten natural, structurally related benzoic acids.

Inhibition of Cancer Cell Proliferation and Antiradical Effects of Decoction, Hydroalcoholic Extract, and Principal Constituents of Hemidesmus indicus R. Br.[Pubmed:25753739]

Phytother Res. 2015 Jun;29(6):857-63.

Indian Sarsaparilla (Hemidesmus indicus R. Br.) is widely used in Indian traditional medicine. In the present work, we explored the effects of decoction, traditional Ayurvedic preparation, and hydroalcoholic extract, a phytocomplex more traditionally studied and commercialized as food supplement in western medicine, from the roots as possible source of chemicals with new functional potential linked to their nutritional uses. The antiproliferative and antioxidant properties were assayed. To test antiproliferative affects, different cancer cell lines, growing both as monolayers (CaCo2, MCF-7, A549, K562, MDA-MB-231, Jurkat, HepG2, and LoVo) and in suspension (K562 and Jurkat) were used. The decoction showed strong activity on HepG2 cells, while the hydroalcoholic extracts were active on HepG2, LoVo, MCF-7, K562, and Jurkat cell lines. Weak inhibition of cancer cell proliferation was observed for the principal constituents of the preparations: 2-hydroxy-4-methoxybenzaldehyde, 2-hydroxy-4-Methoxybenzoic acid, and 3-hydroxy-4-methoxybenzaldehyde that were tested alone. The antiradical activity was tested with 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt tests and inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW 264.7 macrophages. Interesting result has also been obtained for hydroalcoholic extract regarding genoprotective potential (58.79% of inhibition at 37.5 microg/mL).