Dihydroferulic Acid Research Articles

Effect of overexpression of Saccharomyces cerevisiae Pad1p on the resistance to phenylacrylic acids and lignocellulose hydrolysates under aerobic and oxygen-limited conditions

Lignocellulose hydrolysates, obtained by acid hydrolysis for production of bioethanol, contain, in addition to fermentable sugars, compounds that inhibit the fermenting micro-organism. One approach to alleviate the inhibition problem is to use genetic engineering to introduce increased tolerance. Phenylacrylic acid decarboxylase (Pad1p) catalyses a decarboxylation step, by which aromatic carboxylic acids are converted to the corresponding vinyl derivatives. Pad1p-overexpressing Saccharomyces cerevisiae was cultivated in synthetic medium in the presence of model compounds, ferulic acid [(2 E)-3-(4-hydroxy-3-methoxyphenyl)prop-2-enoic acid] and cinnamic acid [(2 E)-3-phenylprop-2-enoic acid], as well as in a dilute acid hydrolysate of spruce to examine the resistance against fermentation inhibitors. Overexpression of S. cerevisiae phenylacrylic acid decarboxylase (Pad1p) resulted in an improved growth rate and ethanol productivity in the presence of ferulic acid, cinnamic acid, and in a dilute acid hydrolysate of spruce. Vinyl guaiacol (2-methoxy-4-vinylphenol) was identified as a major metabolite of ferulic acid, and dihydroferulic acid [3-(4-hydroxy-3-methoxyphenyl)propanoic acid] was detected under oxygen-limited conditions. Styrene (vinylbenzene) and dihydrocinnamic acid (3-phenylpropanoic acid) were identified as metabolites of cinnamic acid. Transformants overexpressing Pad1p had the ability to convert ferulic and cinnamic acid at a faster rate than a control transformant (PAD(C)) not overexpressing Pad1p. This enabled faster growth for Pad1p-overexpressing transformants under both aerobic and oxygen-limited conditions. Pad1p activity was also studied using non-growing cells. The overexpressing transformants showed approximately tenfold higher activity than PAD(C). The Pad1p overexpressing transformants also showed a 22-25% faster glucose consumption rate, a 40-45% faster mannose consumption rate, and a 24-29% faster ethanol production rate in the dilute acid hydrolysate of spruce.

Novel biomarkers of the metabolism of caffeic acid derivatives in vivo

The purpose of this study was to investigate biomarkers of the bioavailability and metabolism of hydroxycinnamate derivatives through the determination of the pharmacokinetics of their urinary elimination and identification of the metabolites excreted. Coffee was used as a rich source of caffeic acid derivatives and human supplementation was undertaken. The results show a highly significant increase in the excretion of ferulic, isoferulic, dihydroferulic acid (3-(4-hydroxy-3-methoxyphenyl)-propionic acid), and vanillic acid postsupplementation relative to the levels presupplementation. Thus, ferulic, isoferulic, and dihydroferulic acids are specific biomarkers for the bioavailability and metabolism of dietary caffeic acid esters. Isoferulic acid is a unique biomarker as it is not a dietary component, however, dihydroferulic acid may well derive from other flavonoids with a structurally related B-ring. 3-Hydroxyhippuric acid has also been identified as an indicator for bioavailability and metabolism of phenolic compounds, and shows a highly significant excretion increase postsupplementation. The results reveal isoferulic acid (and possibly dihydroferulic acid) as novel markers of caffeoyl quinic acid metabolism.

Caffeic acid derivatives in artichoke extract are metabolised to phenolic acids in vivo

The purpose of this study was to investigate the absorption and metabolism of hydroxycinnamates from artichoke extract by determining the urinary excretion of the conjugates. Ten healthy, non smoking volunteers (5 female, 5 male) were given three capsules containing artichoke extract every 4 h (0, 4, 8h) following two days of a low-polyphenol diet. One capsule contained 320 mg of artichoke extract equivalent to 34.3 ± 0.6 mg/g hydroxycinnamates (caffeic acid derivatives) and 5.6 ± 0.1 mg/g flavonoids. Polyphenols and phenolic acids present in the artichoke extract were not detected in the urine either as conjugates or aglycones. However, ferulic, isoferulic, dihydroferulic and vanillic acid were identified as major metabolites after β-glucuronidase treatment of urine. The amount excreted as well as the ratio to that of creatinine, a biomarker for the general excretion rate, increased significantly on the study day compared to the presupplementation day. Thus, the caffeic acid esters found in the artichoke extract capsule are absorbed, metabolised and excreted as methylated phenolic acids such as ferulic, isoferulic, dihydroferulic and vanillic acid.

Phenanthrene and other aromatic constituents of Bulbophyllum vaginatum

Abstract Two new phenanthrenes (4-methoxyphenanthrene-2,3,7-triol and 4-methoxyphenanthrene-2,3,6,7-tetrol) and two new 9,10-dihydrophenanthrenes (5-methoxy-9,10-dihydrophenanthrene-2,3,7-triol and 4-methoxy-9,10-dihydrophenan-threne-2,3,6,7-tetrol), along with the known 4,6-dimethoxyphenanthrene-2,3,7-triol and its 9,10-dihydro derivative, 3,4′,5-trihydroxy-3′-methoxybibenzyl (tristin), dihydroferulic acid, p -coumaric acid, 3,4-dihydroxybenzoic acid and (±)-syringaresinol were isolated from the dichloromethane extract of the orchid Bulbophyllum vaginatum . The structures of these compounds were determined through spectroscopic analysis.

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.

Free and cell wall-bound phenolics and other constituents from healthy and fungus-infected carnation ( Dianthus caryophyllus L.) stems

Phenolic compounds and related substances from carnation stems infected with Fusarium oxysporum f.sp. dianthi were investigated. Healthy stems contained, esterified to wall polysaccharides, among others benzoic, p-hydroxybenzoic, vanillic, trans p-coumaric, cis and trans ferulic, 3-methoxy-4-hydroxy-n-chlorophenyl propionic and (in large amounts) dihydroferulic acid. Fungal infection affected the concentrations of these phenolic acids and induced the accumulation of two types of anthranilic acid derivatives. One group of those compounds included the dianthramides which were further characterized by HPLC-MS. A representative of the other group was identified as 2,2′-dicarboxy-5,5′-dihydroxy-N,N-diphenylamine, a new natural product.

Anaerobic reduction of ferulic acid to dihydroferulic acid by Wolinella succinogenes from cow rumen

Ferulic acid(FA)-modifying microflora from the rumen of cows were acclimated in an FA-containing medium, in which aromatic compounds (dihydroferulic acid, homovanillic acid, carboxymethylphenol and vanillic acid) and volatile fatty acids (acetic, butyric and isobutyric) were detected by gas chromatography and mass spectrometry. An anaerobic curved bacterium was isolated from the rumen microflora. This bacterium was characterized and identified as Wolinella succinogenes according to the method of Holdeman et al. (1977). It could only reduce FA to dihydroferulic acid in the absence of hydrogen acceptors such as nitrate or fumarate and under strictly anaerobic conditions. FA-reducing ability of the bacterium was inhibited to some extent at FA concentrations greater than 5 mM. The FA was reduced more effectively at pH values of 7.0–7.2 than at 6.8 and the reduction was enhanced by the addition of an Ruminococcus albus' culture supernatant.

Absorption and metabolism of gamma-oryzanol in rats.

The metabolism and lymphatic transport of γ-oryzanol in rats were investigated following oral administration of the 14C-labeled compound (triterpenyl esters of ferulic acid-3-14C). Redioactivity excreted in the urine during 72 h after oral administration was 9.8% of the dose (50 mg/kg). Unchanged γ-oryzanol was not detected at all in the urine, but an in situ intestinal absorption experiment suggested that more than 80% of the absorbed radioactivity was transferred into the mesenteric vein as an intact form, though a part was metabolized in the small intestine during absorption. Ferulic acid, dihydroferulic acid, m-hydroxyphenylpropionic acid, m-coumaric acid, m-hydroxyhippuric acid and hippuric acid were identified as the major urinary metabolites. These metabolites, with the exception of hippuric acid, were also excreted in the form of glucuronide or sulfate. The radioactivity transported into the thoracic duct was only 0.3% of the dose, and of this, more than 80% was found to be γ-oryzanol by thin-layer chromatography. From these results, it is considered that γ-oryzanol administered orally is absorbed mainly into the blood via the portal vein system, not into the lymph via the thoracic duct.

Metabolism of trans-ferulic acid by the white-rot fungus sporotrichum pulverulentum

Ferulic acid metabolism was studied in wild-type Sporotrichum pulverulentum and its phenoloxidase-less mutant, Phe 3. High levels of reduced products which included coniferyl aldehyde, dihydroferulic acid and dihydroconiferyl alcohol were detected in culture filtrates. Small amounts of vanillic acid and methoxyhydroquinone were also found. In addition, products which possessed a methylated p-hydroxyl group were identified by mass spectrometry. The phenoloxidase-less mutant gave essentially the same reduced products as the wildtype. These persisted for longer periods in the culture medium. Three fungi known to produce large amounts of phenoloxidases exhibited a markedly different pattern of ferulic acid depletion.

Stages in the biosynthesis of [6]-gingerol in zingiber Officinale

[2-14C,3H,3-3H]Dihydroferulic acid and [1-14C,6-3H]hexanoic acid are shown to be incorporated into (S)-[6]-gingerol in Zingiber officinale, the 3H/14C ratio falling by ½ in the first case but remaining constant in the second; a biogenetic scheme is proposed to accommodate these results, and includes discussion of the late stages of biosynthesis in the light of satisfactory incorporation of [10-3H]-[6]-dehydrogingerol (5).

The metabolism and excretion of curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) in the rat.

Curcumin labelled with deuterium and tritium was prepared. Oral and intraperitoneal doses of [3H]curcumin led to the faecal excretion of most of the radioactivity. 2. Intravenous and intraperitoneal doses of [3H]curcumin were well excreted in the bile of cannulated rats. 3. The major biliary metabolites were glucuronides of tetrahydrocurcumin and hexahydrocurcumin. A minor biliary metabolite was dihydroferulic acid together with traces of ferulic acid. Metabolites were identified using chemical ionization mass spectrometry.