Protocatechuic acid prevents isoproterenol-induced heart failure in mice by downregulating kynurenine-3-monooxygenase

Protocatechuic acid (3,4-dihydroxybenzoic acid) prevents oxidative stress, inflammation and cardiac hypertrophy. This study aimed to investigate the therapeutic effects of protocatechuic acid in an isoproterenol-induced heart failure mouse model and to identify the underlying mechanisms. To establish the heart failure model, C57BL/6NTac mice were given high-dose isoproterenol (80 mg/kg body weight) for 14 days. Echocardiography revealed that protocatechuic acid reversed the isoproterenol-induced downregulation of fractional shortening and ejection fraction. Protocatechuic acid attenuated cardiac hypertrophy as evidenced by the decreased heart-weight-to-body-weight ratio and the expression of Nppb. RNA sequencing analysis identified kynurenine-3-monooxygenase (Kmo) as a potential target of protocatechuic acid. Protocatechuic acid treatment or transfection with short-interfering RNA against Kmo ameliorated transforming growth factor β1–induced upregulation of Kmo, Col1a1, Col1a2 and Fn1 in vivo or in neonatal rat cardiac fibroblasts. Kmo knockdown attenuated the isoproterenol-induced increase in cardiomyocyte size, as well as Nppb and Col1a1 expression in H9c2 cells or primary neonatal rat cardiomyocytes. Moreover, protocatechuic acid attenuated Kmo overexpression–induced increases in Nppb mRNA levels. Protocatechuic acid or Kmo knockdown decreased isoproterenol-induced ROS generation in vivo and in vitro. Thus, protocatechuic acid prevents heart failure by downregulating Kmo. Therefore, protocatechuic acid and Kmo constitute a potential novel therapeutic agent and target, respectively, against heart failure.     

Biotransformation of protocatechuic aldehyde and caffeic acid to vanillin and capsaicin in freely suspended and immobilized cell cultures of Capsicum frutescens

Freely suspended cells and immobilized cell cultures of Capsicum frutescens Mill. were treated with phenylpropanoid intermediates--protocatechuic aldehyde and caffeic acid to study their biotransformation ability. It was found that externally fed protocatechuic aldehyde and caffeic acids were biotransformed to vanillin and capsaicin. It was noted that this culture biotransformed externally fed protocatechuic aldehyde to vanillin more than its conversion to capsaicin, whereas, caffeic acid-treated cultures accumulated more capsaicin than vanillin. The maximum accumulation of vanillin (5.63 mg l(-1)) and capsaicin (3.83 mg l(-1)) was recorded on the 6th and 15th day, respectively in immobilized C. frutescens cell cultures treated with protocatechuic aldehyde, which was 1.8 and 1.4 times higher than in protocatechuic aldehyde-treated freely suspended cell cultures. Caffeic acid-treated immobilized C. frutescens cell cultures accumulated maximum vanillin and capsaicin at 2.68 and 3.03 mg l(-1) culture, respectively, on the 9th and 12th day, which was 1.65 and 1.33 times over freely suspended cultures treated with caffeic acid. The addition of S-adenosyl-L-methionine, a methyl donor, to protocatechuic aldehyde-treated immobilized C. frutescens cell cultures, resulted in accumulation of vanillin (14.08 mg l(-1)) on the 4th day, which was 2.5-fold higher than that in cultures treated with protocatechuic aldehyde alone, suggesting the influence of S-adenosyl-L-methionine on O-methylation of protocatechuic aldehyde, resulting in more vanillin accumulation. The increase in vanillin accumulation was well correlated with an increase in specific activity of caffeic acid O-methyltransferase in protocatechuic aldehyde and S-adenosyl-L-methionine-treated immobilized C. frutescens cell cultures. This study also provides an example for an alternative route to formation of vanillin by C. frutescens cell cultures.     

傣药“雅糯妙”（肾茶）正丁醇部位的化学成分研究

目的：对肾茶正丁醇部位进行系统分离和化合物鉴定,为探索肾茶药理活性物质基础研究奠定基础;方法：采用多种分离纯化技术（硅胶柱层析色谱、反相硅胶柱色谱、SephadesLH-20、半制备型高效液相色谱等）对肾茶正丁醇部位化学成分进行系统的分离纯化,得到单体化合物;运用电喷雾质谱（ESI—MS）、核磁共振氢谱（1HNMR）、核磁共振碳谱（13CNMR／DEPT）和二维核磁共振谱（HSQC,HMBC）对所得单体化合物进行结构鉴定。结果：从肾茶正丁醇部位中共分离得到9个化合物,分别鉴定为：原儿茶酸甲酯（1）、原儿茶醛（2）、原儿茶酸（3）、3,4．二羟基苯乙酸甲酯（4）、3,4一二甲氧基乙酸甲酯（5）、2,5-二羟基苯甲醛（6）、苯甲酸（7）、咖啡酸（8）、迷迭香酸（9）。结论：肾茶正丁醇部位主要化学成分为酚醛、芳香酸及其衍生物,除分离得到之前献报告的咖啡酸、迷迭香酸等外,还首次分离鉴定4个化合物（1,4,5,6）,其中化合物6为首次从植物中分离得到,并首次对该化合物核磁数据进行了归属;化合物1、4、5均为首次从肾荼属植物中分离得到。     

Production of B-group vitamins by two Azotobacter strains with phenolic compounds as sole carbon source under diazotrophic and adiazotrophic conditions

Azotobacter vinelandii strain ATCC 12837 and A. chroococcum strain H23 (CECT 4435) were able to grow on N-free or NH4Cl-amended chemically-defined (Burk's) media, with protocatechuic acid (1-2 mmol 1(-1)) or sodium p-hydroxybenzoate (1-10 mmol 1(-1)) as sole carbon (C) sources. At a concentration of 2 mmol 1(-1), both substrates supported nitrogen fixation (acetylene reduction assay) at similar or higher rates than bacteria grown in control media amended with 2 mmol 1(-1) sodium succinate as C source. The two strains produced the B-group vitamins niacin, pantothenic acid, thiamine, riboflavin and biotin after 72 h of growth in chemically-defined media with 2 mmol 1(-1) protocatechuic acid, sodium phydroxybenzoate or sodium succinate as sole C source, either in N-free media or in media amended with 0.1% NH4Cl. Quantitative production of all vitamins was affected by the use of the different C and N substrates.     

Metabolism of cinnamic, p-coumaric, and ferulic acids by Streptomyces setonii

Streptomyces setonii strain 75Vi2 was grown at 45 degrees C in liquid media containing yeast extract and trans-cinnamic acid, p-coumaric acid, ferulic acid, or vanillin. Gas chromatography, thin-layer chromatography, and mass spectrometry showed that cinnamic acid was catabolized via benzaldehyde, benzoic acid, and catechol; p-coumaric acid was catabolized via p-hydroxybenzaldehyde, p-hydroxybenzoic acid, and protocatechuic acid; ferulic acid was catabolized via vanillin, vanillic acid, and protocatechuic acid. When vanillin was used as the initial growth substrate, it was catabolized via vanillic acid, guaiacol, and catechol. The inducible ring-cleavage dioxygenases catechol 1,2-dioxygenase and protocatechuate 3,4-dioxygenase were detected with an oxygen electrode in cell-free extracts of cultures grown in media with aromatic growth substrates and yeast extract.     

苣叶丹参的多酚类化合物

自云南省文山州产的中药丹参代用植物苣叶丹参(SalviasonchifoliaCYWu)的根中分离得到9个多酚类化合物。即:原儿茶醛,原儿茶酸,咖啡酸,R( )βD(3,4-二羟基苯基)乳酸,3,4-二羟基苯基乙醇酮,迷迭香酸,迷迭香酸甲酯,紫草酸和紫草酸B。它们的结构通过波谱方法得到鉴定。研究结果表明,苣叶丹参含有与正品丹参相似的酚类化合物。     

Enzymatic oxidation of vanillin, isovanillin and protocatechuic aldehyde with freshly prepared Guinea pig liver slices.

BACKGROUND/AIMS: The oxidation of xenobiotic-derived aromatic aldehydes with freshly prepared liver slices has not been previously reported. The present investigation compares the relative contribution of aldehyde oxidase, xanthine oxidase and aldehyde dehydrogenase activities in the oxidation of vanillin, isovanillin and protocatechuic aldehyde with freshly prepared liver slices. METHODS: Vanillin, isovanillin or protocatechuic aldehyde was incubated with liver slices in the presence/absence of specific inhibitors of each enzyme, followed by HPLC. RESULTS: Vanillin was rapidly converted to vanillic acid. Vanillic acid formation was completely inhibited by isovanillin (aldehyde oxidase inhibitor), whereas disulfiram (aldehyde dehydrogenase inhibitor) inhibited acid formation by 16% and allopurinol (xanthine oxidase inhibitor) had no effect. Isovanillin was rapidly converted to isovanillic acid. The formation of isovanillic acid was not altered by allopurinol, but considerably inhibited by disulfiram. Protocatechuic aldehyde was converted to protocatechuic acid at a lower rate than that of vanillin or isovanillin. Allopurinol only slightly inhibited protocatechuic aldehyde oxidation, isovanillin had little effect, whereas disulfiram inhibited protocatechuic acid formation by 50%. CONCLUSIONS: In freshly prepared liver slices, vanillin is rapidly oxidized by aldehyde oxidase with little contribution from xanthine oxidase or aldehyde dehydrogenase. Isovanillin is not a substrate for aldehyde oxidase and therefore it is metabolized to isovanillic acid predominantly by aldehyde dehydrogenase. All three enzymes contribute to the oxidation of protocatechuic aldehyde to its acid.     

Alcohol fermentation using lignin-related compounds as a carbon source

Clostridium indolis JCM 1380 produced 0.24 g/l of ethanol from protocatechuic acid with consumption of about 40% of the substrate (1.2 g/l) at 96 h of cultivation, while Clostridium sphenoides JCM 1415 produced 0.37 g/l of ethanol from p-hydroxybenzoic acid with consumption of about 30% of the substrate (1.5 g/l) at 60 h of cultivation. However, a long lag time was necessary to produce ehtanol from protocatechuic acid by C. indolis, whereas ethanol from p-hydroxybenzoic acid by C. sphenoides was produced without a lag time.     

Liquid chromatography-tandem mass spectrometry analysis of protocatechuic aldehyde and its phase I and II metabolites in rat

A method using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS/MS) analysis was established for the identification of metabolites in rat after oral administration of protocatechuic aldehyde, a major bioactive phenolic acid in the roots of Salvia miltiorrhiza. Eleven metabolites in rat plasma and urine were firstly identified as protocatechuic aldehyde, protocatechuic acid and their methylated, glucuronized or glycine conjugates on the basis of their MS fragmentation behaviors, while nine of these metabolites (except protocatechuic aldehyde and protocatechuic acid) were detected in rat bile. In addition, the possible metabolic pathway was proposed for the first time. In the phase I metabolism, protocatechuic aldehyde could be oxidized to protocatechuic acid. The conjugates would be formed in rat intestine, liver and kidney and excreted from rat urine and bile. Enthrohepatic circulation played an important role in the metabolism of protocatechuic aldehyde. The results proved that the established method was simple, reliable and sensitive, revealing that it could be used to rapid screen and identify the structures of active components responsible for pharmacological effects of protocatechuic aldehyde and to better understand its in vivo metabolism.     

Protocatechuic acid production from trans-ferulic acid by Pseudomonas sp. HF-1 mutants defective in protocatechuic acid catabolism

Summary A trans-ferulic acid-utilizing Pseudomonas sp. HF-1 was isolated from soil samples. Mutant HF-1124, capable of growing on trans-ferulic acid but not on protocatechuic acid, was isolated from HF-1 after mutagenesis with nitrosoguanidine. The optimum temperature was 30°C and the optimum pH was 7.0–8.0 for protocatechuic acid production from trans-ferulic acid by mutant HF-1124. Protocatechuic acid production reached 4 g/l from a concentration of 8 g/l trans-ferulic acid. As a result of co-oxidation of methoxy aromatic compounds by strain HF-1124 grown on acetic acid, protocatechuic acid was formed from vanillin and vanillic acid, and vanillic acid and isovanillic acid were formed from veratric acid. By the co-oxidative demethylation of substituted monomethoxybenzene, m- and p-hydroxybenzoic acids were accumulated from m-and p-anisic acid, respectively, while no products were detected from anisole, o-anisic acid, nitroanisole, methylanisole, methoxyphenol and dimethoxybenzene.     

Degradation of lignin and lignin derivatives by Acinetobacter sp.

An Acinetobacter sp. utilized 2-methoxy-4-formylphenoxyacetic acid, dehydrodivanillyl alcohol, dehydrodiisoeugenol and conidendrin as sole carbon source. It also degraded ¹⁴C-labelled DHP lignin and teakwood lignin. Vanillic acid, protocatechuic acid and catechol were separated from 2-methoxy-4-formylphenoxyacetic acid grown cultures. Both protocatechuic acid and catechol were formed from dehydrodivanillyl alcohol, dehydrodiisoeugenol and conidendrin. On the dimeric lignin model substances this Acinetobacter sp. produced protocatechuate 3,4-dioxygenase and catechol 1,2-dioxygenase.     

Effect of methanol extract of Zanthoxylum piperitum leaves and of its compound,protocatechuic acid,on hepatic drug metabolizing enzymes and lipid peroxidation in rats

The effect of methanol extract and protocatechuic acid from the leaves of Zanthoxylum piperitum on lipid peroxidation and drug metabolizing enzymes were investigated in the liver of bromobenzene-treated rats. The methanol extract and protocatechuic acid reduced the level of lipid peroxide induced by bromobenzene. The methanol extract and protocatechuic acid reduced the activity of aniline hydroxylase that had been increased by bromobenzene, while did not affect the activities of aminopyrine N-demethylase and glutathione S-transferase. The methanol extract and compound effectively restored the activity of epoxide hydrolase which had been decreased by bromobenzene. These results may suggest that the methanol extract of Z. piperitum and protocatechuic acid prevented lipid peroxidation by reducing the activity of aniline hydroxylase, an epoxide-producing enzyme, and by enhancing the activity of epoxide hydrolase, an epoxide-removing enzyme, in rats that had been intoxicated with bromobenzene.     

Degradation of Methoxylated Benzoic Acids by a Nocardia from a Lignin-Rich Environment: Significance to Lignin Degradation and Effect of Chloro Substituents

Strain A81 of Nocardia corallina hydroxylates or demethylates p-anisic acid to p-hydroxybenzoic acid and isovanillic acid. It demethylates veratric acid to a mixture of vanillic and isovanillic acids. These are both demethylated to protocatechuic acid, which undergoes ring cleavage to afford beta-carboxy-cis-cis-muconic acid. The intermediacy of protocatechuic acid in the catabolic pathway of veratric acid was confirmed by blocking ring cleavage with an additional substituent in the ring: 5-chlorovanillic acid was demethylated to 5-chloro-protocatechuic acid, which accumulated. Chloro substituents in the ring of other methoxylated benzoic acids also arrested their normal metabolism by the Nocardia: an ortho-chloro substituent thwarted both demethylation and ring-opening. ortho-Hydroxylation of p-methoxybenzoic acid to isovanillic acid was unaffected by a chlorine ortho to the methoxyl group. Washed whole cells of veratric acid-grown N. corallina A81 produced no detected structural changes in an isolated lignin. The implications of this observation are discussed.     

刺楸中酚性成分研究

采用常压柱色谱、半制备型高效液相色谱以及制备型薄层色谱等色谱技术结合重结晶等分离纯化手段,从刺楸根中分离得到6个酚性化学成分,通过理化性质和波谱分析鉴定所得化合物分别为苔色酸乙酯(1),2-羟基-4-甲氧基-3,6-二甲基苯甲酸(2),香草醛(3),原儿茶醛(4),原儿茶酸(5)和3-甲氧基苯甲醛(6).所有化合物均为首次从该属植物中获得.     

Effect of natural phenols on the catalytic activity of cytochrome P450 2E1

The effect of protocatechuic acid, tannic acid and trans-resveratrol on the activity of p-nitrophenol hydroxylase (PNPH), an enzymatic marker of CYP2E1, was examined in liver microsomes from acetone induced mice. trans-Resveratrol was found to be the most potent inhibitor (IC(50) = 18.5 +/- 0.4 microM) of PNPH, while protocatechuic acid had no effect on the enzyme activity. Tannic acid with IC(50) = 29.6 +/- 3.3 microM showed mixed- and trans-resveratrol competitive inhibition kinetics (K(i) = 1 microM and 2.1 microM, respectively). Moreover, trans-resveratrol produced a NADPH-dependent loss of PNPH activity, suggesting mechanism-based CYP2E1 inactivation. These results indicate that trans-resveratrol and tannic acid may modulate cytochrome P450 2E1 and influence the metabolic activation of xenobiotics mediated by this P450 isoform.     

Polyphenol Oxidase in the Respiration and the Salt Uptake of Storage Tissues3

The respiration and potassium uptake of beet and potato diskshave been measured in the presence of protocatechuic acid. Itis found that protocatechuic acid in a concentration of 10^–3to 3 x 10^–3 M at pH 6, stimulates both oxygen uptake andcarbon dioxide output. This stimulation of respiration is accompaniedby a reduction in potassium uptake. Experiments with carbon monoxide indicate that polyphenol oxidasemediates the ‘extra’ respiration in the presenceof protocatechuic acid, although this enzyme does not appearto play any part in the normal respiration, at least in 5 percent oxygen. These results are considered in relation to previousclaims concerning the role of polyphenol oxidase in salt uptakeand respiration of potato disks. Potassium uptake by potato disks is light-reversibly inhibitedby carbon monoxide, indicating the participation of cytochromeoxidase in salt uptake in this, as in other tissues.     

Metabolism of Benzoic Acid by Bacteria: 3,5- Cyclohexadiene-1,2-Diol-1-Carboxylic Acid Is an Intermediate in the Formation of Catechol

3,5-Cyclohexadiene-1,2-diol-1-carboxylic acid (1,2-dihydro-1,2-dihydroxy-benzoic acid) is converted enzymatically to catechol in cell extracts from Acinetobacter, Alcaligenes, Azotobacter, and three Pseudomonas species. This enzymatic activity is present only in cultures which have been grown in the presence of benzoic acid, and which convert benzoic acid to catechol rather than to protocatechuic acid. The reaction is assayed by the concomitant formation of reduced nicotinamide adenine dinucleotide from nicotinamide adenine dinucleotide. The conversion of [(14)C]benzoic acid to [(14)C]dihydrodihydroxybenzoic acid is demonstrated in cell extracts. A scheme for the conversion of benzoic acid to catechol in bacteria is presented, involving the formation of dihydrodihydroxybenzoic acid from benzoic acid by a dioxygenase which is unstable in cell extracts, followed by the dehydrogenation and decarboxylation of dihydrodihydroxybenzoic acid to catechol by a previously undescribed enzyme. Experiments with anthranilic acid and phthalic acid suggest that dihydrodihydroxybenzoic acid is a metabolite unique to benzoic acid metabolism. Two new methods for assaying benzoic acid dioxygenase are suggested.     

ACCUMULATION OF 4-O-β-D-GLUCOSIDE OF PROTOCATECHUIC ACID IN THE LEFT COLLETERIAL GLAND OF THE COCKROACH, PERIPLANETA AMERICANA. II. HORMONAL REGULATION

The amount of protocatechuic acid glucoside in the left colleterial gland changes with the reproductive cycle. Allatectomy, beheading and injection of actinomycin D cause inhibition of the accumulation of glucoside, but glucoside resumes to accumulate in the left colleterial gland with the reimplantation of corpora allata into the allatectomized cockroaches.
When ¹⁴C-glucose was injected in normal animals, radioactive glucoside was accumulated in the left colleterial gland whereas in the allatectomized cockroaches, it was not accumulated in the gland but was found abundantly in blood.
The level of protocatechuic acid glucoside synthetase activity of the fat body tissue and of the left colleterial gland was assayed. The enzyme activity in the left colleterial gland was not affected by allatectomy but that in the fat body was slightly affected.
The mechanism of accumulation of protocatechuic acid glucoside in the left colleterial gland and the endocrine control on the accumulation are discussed.     

镉胁迫对丹参生长及有效成分积累的影响研究

采用盆栽试验方法,研究了镉（Cd2＋）对丹参（Salvia miltiorrhiza Bunge）的生长及其有效成分积累的影响。结果表明,镉胁迫下丹参的生长受到了显著抑制,体内Cd2＋残留量、可溶性蛋白含量和膜脂过氧化程度显著增加,叶绿素含量降低。与对照相比,镉胁迫下丹参叶片水溶性酚酸类化合物咖啡酸和迷迭香酸的含量显著降低（P〈0．05）,原儿茶酸含量增加,丹参素、原儿茶醛和丹酚酸B的含量也降低,但变化均不显著（P〉0．05）。而根系中这6种酚酸类化合物含量均降低,其中迷迭香酸的含量变化极显著（P〈0．01）。镉胁迫下丹参根系脂溶性丹参酮类化合物二氢丹参酮、丹参酮I和隐丹参酮含量均显著降低,而丹参酮lIA含量变化不显著。丹参叶片中水溶性酚酸类化合物合成关键酶苯丙氨酸解氨酶（PAL）和酪氨酸氨基转移酶（TAT）的活性显著降低,而肉桂酸4一羟化酶（C4H）和4一香豆酸CoA连接酶（4CL）的活性显著升高。这些结果均说明镉胁迫可以降低丹参的产量和质量。     

New aspects of co-regulation of decarboxylation and demethylation activities in Nocardia

Vanillic acid at 0.2% concentration in the medium of Nocardia autotrophic DSM 43100 leads to cyclic production of guaiacol; protocatechuic and p-hydroxybenzoic acids as well as catechol appear at the same time in the medium instead of isovanillic acid, which accumulates at lower vanillic acid concentration. Transformation of catechol formed into guaiacol by methylation with formaldehyde, and successively into protocatechuic acid by carboxylation seems possible. Successive reactions of methylation/demethylation and carboxylation/decarboxylation result in cyclic production of guaiacol.