Formation Of Vanillic Acid Research Articles

Biotransformation of ferulic acid into vanillyl alcohol and vanillic acid employing thermophilic bacterium Caldimonas thermodepolymerans

Caldimonas thermodepolymerans, a Gram-negative, moderately thermophilic bacterium, exhibits a remarkable biotechnological potential. Given the presence of genes in its genome dedicated to the metabolization of ferulic acid (FA), this study aimed to explore the bacterium's capability for biotransforming FA into high-value metabolites. The results unequivocally demonstrate the bacterium's proficiency in the efficient and rapid conversion of FA into vanillyl alcohol (VOH) and vanillic acid (VA). By manipulating key cultivation parameters, such as adjusting initial FA doses and varying cultivation periods, the product profile can be tailored. Higher initial doses and shorter cultivation periods favor the production of VOH, while lower FA doses and extended cultivation periods lead to the predominant formation of VA. Furthermore, the process can be operated in a repeated-batch scenario. This underscores the potential of C. thermodepolymerans for industrial biotransformation of FA, presenting a promising avenue for leveraging its capabilities in practical applications.

In Vitro Antibacterial Activity and Mechanism of Vanillic Acid against Carbapenem-Resistant Enterobacter cloacae.

Vanillic acid (VA) is a flavoring agent found in edible plants and fruits. Few recent studies exhibited robust antibacterial activity of VA against several pathogen microorganisms. However, little was reported about the effect of VA on carbapenem-resistant Enterobacter cloacae (CREC). The purpose of the current study was to assess in vitro antimicrobial and antibiofilm activities of VA against CREC. Here, minimum inhibitory concentrations (MIC) of VA against CREC was determined via gradient diffusion method. Furthermore, the antibacterial mode of VA against CREC was elucidated by measuring changes in intracellular adenosine triphosphate (ATP) concentration, intracellular pH (pHin), cell membrane potential and membrane integrity. In addition, antibiofilm formation of VA was measured by crystal violet assay and visualized with field emission scanning electron microscopy (FESEM) and confocal laser scanning microscopy (CLSM). The results showed that MIC of VA against E. cloacae was 600 μg/mL. VA was capable of inhibiting the growth of CREC and destroying the cell membrane integrity of CREC, as confirmed by the decrease of intracellular ATP concentration, pHin and membrane potential as well as distinctive variation in cellular morphology. Moreover, crystal violet staining, FESEM and CLSM results indicated that VA displayed robust inhibitory effects on biofilm formation of CREC and inactivated biofilm-related CREC cells. These findings revealed that VA exhibits potent antibacterial activity against CREC, and thus has potential to be exploited as a natural preservative to control the CREC associated infections.

Mechanistic Investigation of the Catalyzed Cleavage for the Lignin β-O-4 Linkage: Implications for Vanillin and Vanillic Acid Formation

The depolymerization of kraft lignin with a copper–vanadium hydrotalcite-like catalyst (HTc-Cu-V) and V(acac)3/Cu(NO3)2·3H2O mixtures to monomeric aromatic aldehydes and aromatic acids such as vanillin and vanillic acid using molecular oxygen as oxidant is reported. The obtained products correlate to model-based studies with erythro-1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol (1a). Kinetic investigations with 1a demonstrate that there is a combined effect of V(acac)3 together with Cu(NO3)2·3H2O that enhances the catalytic activity and increases the selectivity and yield for the cleavage products veratric acid and veratraldehyde. Veratric acid is formed through reaction pathways involving either the transient oxidation products 1-(3,4-dimethoxyphenyl)-3-hydroxy-2-(2-methoxyphenoxy)propan-1-one (2) and 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)prop-2-en-1-one (5) or through overoxidation of veratraldehyde. The formation of veratraldehyde likely proceeds through C–C bond cleavage involving...

Biotransformation of ferulic acid to 4-vinylguaiacol by a wild and a diploid strain of Aspergillusniger

Ferulic acid biotransformation has a number of interesting industrial uses. Ferulic acid biotransformation by the wild strain Aspergillusniger C28B25 and a diploid strain DAR2, obtained by parasexual recombination, was studied. The wild strain of A.niger C28B25 biotransforms ferulic acid to vanillic acid (VA); while the diploid strain DAR2 preferentially decarboxylates ferulic acid to 4-vinylguaiacol (4VG). The latter was identified by mass spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopy, and quantified by HPLC. The diploid strain A.niger DAR2 and the wild strain showed a ferulic acid conversion of 64% and 36%, respectively. Molar yields show that the formation of 4VG was preferred, being as much as 4.4 times higher than the formation of VA in diploid strain cultures. Differential regulation of enzymes involved in the biotransformation of ferulic acid may explain the accumulation of 4VG by diploid DAR2. This strain produced both 4VG and VA.

Degradation of bioactive spice compound: curcumin during domestic cooking

Many of the health beneficial physiological effects of the spice—turmeric (Curcuma longa), documented in recent years are attributable to the major flavour and colouring compound curcumin. Considerable decrease in the concentration of bioactive compound curcumin has been observed during the heat processing of turmeric. This study was aimed at understanding the nature of altered/degraded compounds formed from the bioactive spice compound—curcumin as a result of heat treatment encountered during domestic cooking. Among several of the degradation compounds of curcumin, three major ones were characterized as ferulic acid, vanillin and vanillic acid on the basis of their UV absorption, proton NMR spectra and mass spectral data of LC fractions, as well as by comparison of the three identified compounds with respective standards. The study confirmed the vulnerability of the diketone bridge in curcumin molecule to heat. In addition, formation of vanillic acid and vanillin indicated that the molecule is sensitive to heat at the first carbon atom of the alkyl chain which is connecting the two phenyl moieties.

Aldehyde Oxidase Activity and Inhibition in Hepatocytes and Cytosolic Fraction from Mouse, Rat,Monkey and Human

Aldehyde oxidase (AO) is a cytosolic enzyme that contributes to the Phase I metabolism of xenobiotics in human and preclinical species. We compared AO activity in cytosol and cryopreserved hepatocytes from human, monkey, rat and mouse livers to assess species differences. We also evaluated possible species differences in drug interactions using seven drugs known to inhibit human cytosolic AO i.e. raloxifene, perphenazine, menadione, maprotiline, ketoconazole, erythromycin, and estradiol. AO activity was measured using the formation of vanillic acid from vanillin. The rate of vanillic acid formation was 2 +/- 0.2 nmol/min/mg in human liver cytosol and 0.79 +/- 0.45 nmol/min/million cells in cryopreserved human hepatocytes. AO activity (V(max,app)) was highest in monkey and lowest in rat. Mouse liver cytosol had the lowest K(m,app) (1.44 +/- 0.16 microM) and highest intrinsic clearance (8.97 ml/min/mg) and rat liver cytosol the highest K(m,app) (10.9 +/- 1.2 microM) and lowest intrinsic clearance (0.47 ml/min/mg). There was a 4.25-fold difference in AO activity between the 5 human hepatocyte preparations. Drug interaction studies with the seven marketed drugs revealed marked species-specific inhibition. Our data indicates major differences in the rate of AO metabolism, and inhibition of AO across species, indicating that results from animal studies cannot be safely extrapolated to humans. Cryopreserved hepatocytes and cytosolic fractions from animals and humans provide qualitatively similar data within the species.

Inhibitory Effects of Catechin Gallates on o-Methyltranslation of Protocatechuic Acid in Rat Liver Cytosolic Preparations and Cultured Hepatocytes

Flavonoids including tea catechins and gallic acid esters were characterized for their ability to inhibit o-methyltranslation of protocatechuic acid (PCA) to form vanillic acid (VA) in rat liver cytosolic preparations and cultured hepatocytes. Flavonols and flavones exhibited different behaviors in inhibiting the formation of VA between the cell-free enzymatic preparations and the intact cells. The underlying mechanism of the inhibitory effects of flavonols and flavones on PCA o-methylation in cultured hepatocytes may not be due to the inhibition of the enzyme activity of catechol o-methyl transferase (COMT). Catechin gallates inhibited PCA o-methylation in liver cytosolic preparations with markedly higher potency than other flavonoids. As compared with catechin gallates, ungallated catechins had two to three orders of magnitude lower efficiency in inhibiting cytosolic PCA o-methylation. Gallic acid esters inhibited cytosolic PCA o-methylation with strong potency almost equal to that of catechin gallates. These results suggest that the COMT-inhibitory activity of catechin gallates is derived from the presence of the galloyl moiety at the C3 position in the C-ring. Catechin gallates and gallic acid esters inhibited PCA o-methylation in cultured hepatocytes with two orders of magnitude lower efficacy than that in cytosolic preparations. The inhibitory effects of catechin gallates and gallic acid esters on cellular PCA o-methylation appear to be due to the direct inhibition of COMT activity.

Biotransformation of ferulic acid and related compounds by mutant strains of Pseudomonas fluorescens

Pseudomonas fluorescens strain FE2 isolated in the presence of ferulic acid was able to grow on hydroxylated and methoxylated compounds bearing the hydroxyl group in the para position. By ethylmethansulphonate (EMS) and transposon mutagenesis, mutants unable to utilize ferulic acid have been selected. The metabolic characterization of the wild-type strain and its mutants indicates that ferulic acid was degraded through the formation of vanillic acid. Mutant FE2B in co-oxidation experiments with glutamate, is able to transform ferulic and dihydroferulic acid into vanillic acid, 4-hydroxycinnamic acid and 3 (4-hydroxyphenyl)-propanoic acid into 4-hydroxybenzoic acid, and 3-hydroxycinnamic acid into 3-hydroxybenzoic acid. The bioconversion of hydroxylated aromatic substrates by the FE2B mutants suggests that the presence of a hydroxyl group on the aromatic ring is required for deacetylase activity.