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PubMed2005

Purification and characterization of a chlorogenic acid hydrolase from Aspergillus niger catalysing the hydrolysis of chlorogenic acid.

Among 15 Aspergillus strains, Aspergillus niger BRFM 131 was selected for its high chlorogenic acid hydrolase activity. The enzyme was purified and characterized with respect to its physico-chemical and kinetic properties. Four chromatographic steps were necessary to purify the protein to homogeneity with a recovery of 2%. Km of the chlorogenic acid hydrolase was estimated to be 10 microM against chlorogenic acid as substrate. Under native conditions, the protein presented a molecular mass of 170 kDa, and SDS-PAGE analysis suggested the presence of two identical 80 kDa subunits. Isoelectric point was 6.0; pH optimum for activity was determined to be 6.0 and temperature optima to be 55 degrees C. The N-terminal sequence did not present any homology with other cinnamoyl ester hydrolases previously described suggesting the purification of a new protein. The chlorogenic acid hydrolase was used successfully for the production of caffeic acid, which possesses strong antioxidant properties, from natural substrates specially rich in chlorogenic acid like apple marc and coffee pulp.

Aspergillus niger↗
PubMed2001

Structure of green pigment formed by the reaction of caffeic acid esters (or chlorogenic acid) with a primary amino compound.

A marked greening observed in some foods such as sweet potato, burdock, and others during food processing was shown to be due to green pigment formation by the condensation reaction of two molecules of chlorogenic acid or caffeic acid ester with one molecule of a primary amino compound under aeration in alkaline solution. Reduction of the green pigment by ascorbic acid or NaBH4 gave a yellow product, which readily turn green and then blue in air. The reduced and acetylated product of the green pigment was identified to be a novel trihydroxy benzacridine derivative, and the yellowish ethanol solution of this product immediately turned green upon addition of butyl amine or diluted alkali. Therefore, the green pigment was assumed to be an oxidized quinone type product of trihydroxy benzacridine. This identification of the structure was supported by the correspondence of the measured absorption spectra with those calculated by the molecular orbital method. A possible charge transfer complex between products of different oxidation steps in green solution was proposed.

Acetylation↗
PubMed2003

The dietary hydroxycinnamate caffeic acid and its conjugate chlorogenic acid increase vitamin e and cholesterol concentrations in Sprague-Dawley rats.

Vegetarian diets are correlated with a reduced risk of developing cardiovascular disease and comprise a great variety of bioactive compounds, including hydroxycinnamic acid derivatives. Therefore, this study aimed to identify dietary hydroxycinnamic acid derivatives that may alter two important factors related to the development of cardiovascular disease, namely, tocopherol (T) and cholesterol (C) concentrations in the body. The effects of caffeic acid (CA), chlorogenic acid (CGA), and ferulic acid (FA) on alpha-T, gamma-T, and C levels in blood plasma, liver, and lungs were investigated after these compounds had been fed to rats for 4 weeks at concentrations of 2 g/kg in semisynthetic diets. None of the regimens affected weight gain, feed intake, or absolute weights of livers and lungs, although CA increased the liver weight relative to the body weight (P < 0.05). CA- and CGA-fed animals showed a tendency toward sparing vitamin E in all tissues, but statistical significance was obtained only for gamma-T in the liver of CA-fed animals (P < 0.005) and for alpha-T in the lungs of CGA-treated rats (P < 0.05). CGA supplementation reduced concentrations of lipids in the lung tissue (P < 0.05). CA and CGA elevated the concentrations of C in liver tissue and lipids to a similar extent, but only CA decreased the ratio of high-density lipoprotein C to total C in blood plasma (P < 0.05 for all effects). Animals eating FA showed T and C values comparable to those in the control group. In conclusion, this study demonstrates that dietary caffeic and chlorogenic acid may elevate tocopherols and cholesterol in vivo.

Administration, Oral↗
PubMed2003

Genetic mapping of a caffeoyl-coenzyme A 3-O-methyltransferase gene in coffee trees. Impact on chlorogenic acid content.

Chlorogenic acids (CGA) are involved in the bitterness of coffee due to their decomposition in phenolic compounds during roasting. CGA mainly include caffeoyl-quinic acids (CQA), dicaffeoyl-quinic acids (diCQA) and feruloyl-quinic acids (FQA), while CQA and diCQA constitute CGA sensu stricto (CGA s.s.). In the two cultivated species Coffea canephora and Coffea arabica, CGA s.s. represents 88% and 95% of total CGA, respectively. Among all enzymes involved in CGA biosynthesis, caffeoyl-coenzyme A 3-O-methyltransferase (CCoAOMT) is not directly involved in the CGA s.s. pathway, but rather in an upstream branch leading to FQA through feruloyl-CoA. We describe how a partial cDNA corresponding to a CCoAOMT encoding gene was obtained and sequenced. Specific primers were designed and used for studying polymorphism and locating the corresponding gene on a genetic map obtained from an interspecific backcross between Coffea liberica var. Dewevrei and Coffea pseudozanguebariae. Offspring of this backcross were also evaluated for the chlorogenic acid content in their green beans. A 10% decrease was observed in backcross progenies that possess one C. pseudozanguebariae allele of the CCoAOMT gene. This suggests that CGA s.s. accumulation is dependent on the CCoAMT allele present and consequently on the activity of the encoded isoform, whereby CGA accumulation increases as the isoform activity decreases. Possible implications in coffee breeding are discussed.

Alleles↗
PubMed1973

Studies on chlorogenic Acid biosynthesis in sweet potato root tissue in special reference to the isolation of a chlorogenic Acid intermediate.

Marked polyphenol production takes place in root tissue of sweet potato, Ipomoea batatas Lam. cv. Norin 1, in response to slicing. A possible intermediate, tentatively termed compound V, of chlorogenic acid biosynthesis was isolated from the root tissue administrated with t-cinnamic acid-2-(14)C. Compound V was proved to be an ester whose acid moiety was t-cinnamic acid, and the hydroxyl group-bearing moiety appeared to be a carbohydrate. Compound V was suggested to be the first intermediate after t-cinnamic acid involved in the chlorogenic acid biosynthetic pathway by the following three results. (a) label of t-cinnamic acid-2-(14)C was distributed in compound V first, then transferred to chlorogenic acid and isochlorogenic acid, isomers of dicaffeoylquinic acid; (b) specific radioactivity of compound V increased prior to that of the fraction containing chlorogenic acid and isochlorogenic acids and decreased prior to that of the latter; and (c) label of compound V was efficiently incorporated into chlorogenic acid and isochlorogenic acid.

Journal Article↗
PubMed2001

Development of free radical products during the greening reaction of caffeic acid esters (or chlorogenic acid) and a primary amino compound.

ESR spectra were measured directly on a marked greening reaction mixture of Et-caffeate and a primary amino compound in alkali solution under aeration. A clear hyperfine structure was commonly detected early in the greening reaction with different amino compounds. Its hyperfine spectrum split into seven peaks was analyzed and found to be due to the oxidized free radical product of the Et-caffeate using an authentic sample system. Another type of hyperfine ESR spectrum was observed later in the reaction, and was altered with different amino compounds. The hyperfine structure for n-butylamine split into 12 lines. The latter type of free radical products were assumed to be a semiquinone type radical compound of the trihydroxy benzacridine derivative, which was identified as the principal structure of the green and yellow pigments formed by this greening reaction system. A formation mechanism of the green pigment and related products involving these free radical products is proposed.

Acridines↗
PubMed2006

Uptake and metabolism of hydroxycinnamic acids (chlorogenic, caffeic, and ferulic acids) by HepG2 cells as a model of the human liver.

Hydroxycinnamic acids are antioxidant polyphenols common in the human diet, although their potential health benefits depend on their bioavailability. To study the hepatic uptake and metabolism, human hepatoma HepG2 cells were incubated for 2 and 18 h with caffeic, ferulic, and chlorogenic acids. Moderate uptake of caffeic and ferulic acids was observed versus a low absorption of chlorogenic acid, where esterification of the caffeic acid moiety markedly reduced its absorption. Methylation was the preferential pathway for caffeic acid metabolism, along with glucuronidation and sulfation, while ferulic acid generated glucuronides as the only metabolites. Ferulic acid appeared to be more slowly taken up and metabolized by HepG2 cells than caffeic acid, with 73% and 64% of the free, nonmetabolized molecules detected in the culture medium after 18 h, respectively. In conclusion, hydroxycinnamic acids can be metabolized by the liver as suggested by the results obtained using HepG2 cells as a hepatic model system.

Absorption↗
PubMed1990

Properties and Activity Changes of Chlorogenic Acid:Glucaric Acid Caffeoyltransferase From Tomato (Lycopersicon esculentum).

A novel acyltransferase from cotyledons of tomato (Lycopersicon esculentum Mill.), which catalyzes the transfer of caffeic acid from chlorogenic acid (5-O-caffeoylquinic acid) to glucaric and galactaric acids, was purified with a 2400-fold enrichment and a 4% recovery. The enzyme showed specific activities (theoretical V(max) per milligram of protein) of 625 nanokatals (caffeoylglucaric acid formation) and 310 nanokatals (caffeoylgalactaric acid formation). On sodium dodecyl sulfate-polyacrylamide gel electrophoresis it gave an apparent M(r) of 40,000, identical to the value obtained by gel filtration column chromatography. Highest activity was found at pH 5.7, which was constant over a range of 20 to 120 millimolar K-phosphate. The isoelectric point of the enzyme was at pH 5.75. The reaction temperature optimum was at 38 degrees C and the apparent energy of activation was calculated to be 57 kilojoules per mole. The apparent K(m) values were 0.4 millimolar for glucaric acid, 1.7 millimolar for galactaric acid, and with both acceptors as second substrates 20 millimolar for chlorogenic acid. The relative ratio of the V(max)/K(m) values for glucaric acid and galactaric acid was found to be 100:12. Substrate-competition experiments support the conclusion that one single enzyme is responsible for both the glucaric and galactaric acid ester formation with marked preference for glucaric acid. It is proposed that the enzyme be called chlorogenic acid:glucaric acid O-caffeoyltransferase (EC 2.3.1.-). The three caffeic acid-dependent enzyme activities involved in the formation of the glucaric and galactaric acid esters, the chlorogenic acid:glucaric acid caffeoyltransferase as the key activity as well as the caffeic acid:CoA ligase and the caffeoyl-CoA:quinic acid caffeoyltransferase as the preceding activities, were determined. The time course of changes in these activities were followed during development of the seedling in the cotyledons and growth of the young plant in the first and second leaf. The results from tomato seedlings suggest a sequential appearance of these enzymes.

Journal Article↗
PubMed2003

The metabolic pathway of salicylic acid rather than of chlorogenic acid is involved in the stress-induced flowering of Pharbitis nil.

We examined the involvement of chlorogenic acid (CGA) and salicylic acid (SA) in the stress-induced flowering of Pharbitis nil (synonym Ipomoea nil). The incorporation efficiency of exogenously applied CGA and the deactivation rate of incorporated CGA were determined in cotyledons by high-performance liquid chromatography. The assay plants could not incorporate a sufficient amount of CGA via roots. The perfusion technique by which the assay solution was forced into the plant from the cut end of the hypocotyl improved the efficiency of CGA incorporation. However, no flower-inducing activity was detected, indicating that CGA was not involved in flowering. It was concluded that the close correlation between CGA content and flowering response is merely coincidence or a parallelism. Flowering under long-day conditions induced by low-temperature stress was completely inhibited by aminooxyacetic acid (AOA), an inhibitor of phenylalanine ammonialyase. The flower-inhibiting effect of AOA was nullified by co-applied t-cinnamic acid and by benzoic acid. This indicates that the metabolic pathway from t-cinnamic acid to SA via benzoic acid is involved in the stress-induced flowering. The results indicate that the metabolic pathway of SA is involved in the stress-induced flowering of P. nil not the metabolic pathway of CGA.

Aminooxyacetic Acid↗
PubMed1986

Inhibition by chlorogenic acid of haematin-catalysed retinoic acid 5,6-epoxidation.

Chlorogenic acid (3-O-caffeoylquinic acid) inhibited haematin- and haemoglobin-catalysed retinoic acid 5,6-epoxidation. Some other phenol compounds (caffeic acid and 4-hydroxy-3-methoxybenzoic acid) also showed inhibitory effects on the haematin- and haemoglobin-catalysed epoxidation, but salicylic acid did not. Of the above compounds, caffeic acid and chlorogenic acid were potent inhibitors compared with the other two, suggesting that the o-hydroquinone moiety of chlorogenic acid and caffeic acid is essential to the inhibition of the epoxidation. Although caffeic acid inhibited retinoic acid 5,6-epoxidation requiring the consumption of O2, formation of retinoic acid radicals was not inhibited on the addition of caffeic acid to the incubation mixture. The above results suggest that caffeic acid does not inhibit the formation of retinoic acid radicals but does inhibit the step of conversion of retinoic acid radical into the 5,6-epoxide.

Caffeic Acids↗
PubMed2001

Chlorogenic acid and caffeic acid are absorbed in humans.

Chlorogenic acid, an ester of caffeic acid and quinic acid, is a major phenolic compound in coffee; daily intake in coffee drinkers is 0.5-1 g. Chlorogenic acid and caffeic acid are antioxidants in vitro and might therefore contribute to the prevention of cardiovascular disease. However, data on the absorption of chlorogenic acid and caffeic acid in humans are lacking. We determined the absorption of chlorogenic acid and caffeic acid in a cross-over study with 4 female and 3 male healthy ileostomy subjects. In such subjects, degradation by the colonic microflora is minimal and absorption can be calculated as the amount ingested minus the amount excreted in ileostomy effluent. The ileostomy subjects ingested 2.8 mmol chlorogenic acid and 2.8 mmol caffeic acid on separate days in random order and subsequently collected ileostomy fluid and urine for 24 h. Absorption of chlorogenic acid was 33 +/- 17% (mean +/- SD) and of caffeic acid 95 +/- 4%. Traces of the ingested chlorogenic acid and 11% of the ingested caffeic acid were excreted in urine. Thus, one third of chlorogenic acid and almost all of the caffeic acid were absorbed in the small intestine of humans. This implies that part of chlorogenic acid from foods will enter into the blood circulation, but most will reach the colon.

Absorption↗
PubMed2004

Interactions of human serum albumin with chlorogenic acid and ferulic acid.

The interactions of chlorogenic acid and ferulic acid with human serum albumin (HSA) have been investigated by fluorescence and Fourier transformed infrared (FT-IR) spectrometry. Fluorescence results showed that one molecule of protein combined with one molecule of drugs at the molar ratio of drug to HSA ranging from 1 to 10, and their binding affinities (KA) are 4.37 x 10(4) M(-1) and 2.23 x 10(4) M(-1) for chlorogenic acid and ferulic acid, respectively. The primary binding site for chlorogenic acid is most likely located on IIA and that for ferulic acid in IIIA. The main mechanism of protein fluorescence quenching was static quenching process. Combining the curve-fitting results of infrared amide I and amide III bands, the alterations of protein secondary structure after drug complexation were estimated. With increasing the drug concentration, the protein alpha-helix structure decreased gradually and the reduction of protein alpha-helix structure reached about 7% and 5% for protein binding with chlorogenic acid and ferulic acid individually at the drug to protein molar ratio of 30. This indicated a partial unfolding of HSA in the presence of the two acids. From the fluorescence and FT-IR results, the binding mode was discussed.

Binding Sites↗
PubMed2004

Application of preparative high-speed counter-current chromatography for separation of chlorogenic acid from Flos Lonicerae.

Chlorogenic acid, an ester formed between caffeic acid and quinic acid, is a major phenolic compound in the traditional Chinese medicinal herb Flos Lonicerae. The separation and purification of chlorogenic acid from the crude extract of Flos Lonicerae was achieved by high-speed counter-current chromatography (HSCCC). A high acid, highly polar two-phase solvent system containing n-butanol-acetic acid-water (4:1:5) was run on a preparative scale. The upper phase was used as the mobile phase in the head to tail elution mode. A 300-mg quantity of the crude extract containing 5.97% chlorogenic acid was loaded on a 342-ml HSCCC column. Double separations were performed with the same solvent system yielding 16.9 mg chlorogenic acid at 94.8% purity with approximately 90% recovery.

Chlorogenic Acid↗
PubMed1998

Iron chelation by chlorogenic acid as a natural antioxidant.

Chlorogenic acid, a dietary antioxidant, effectively inhibited the iron-induced lipid peroxidation of bovine liver microsomes in a concentration-dependent manner. In the Fenton-type reaction, chlorogenic acid inhibited the production of the hydroxyl radical by iron-EDTA or iron-ADP, while iron plus chlorogenic acid did not generate the hydroxyl radical. The formation of an iron complex with chlorogenic acid was demonstrated by UV/vis absorbance spectroscopic, ESR and 1H-NMR studies. The ferric complex with chlorogenic acid was in the ferric high-spin state near rhombicity, and had no radical scavenging activity. The results indicate that chlorogenic acid prevented the formation of the hydroxyl radical by forming a chelate with iron whose complex cannot catalyze the Fenton-type reaction.

Animals↗