Protocatechuic Aldehyde Research Articles

Polyphenolic Constituents from the Aerial Parts of Thymus quinquecostatus var. japonica Collected on Ulleung Island

Phytochemical investigation on the polar constituents in the aerial parts of Thymus quinquecostatus var. japonica resulted in the isolation of three flavonoids along with four known phenolic components. The isolated compounds were characterized as 2(S)-5,7,3′,5′-tetrahydroxyflavanone (1), (+)-taxifolin (2), (+)-aromadendrin (3), rosmarinic acid (4), caffeic acid (5), protocatechuic acid (6), and protocatechuic aldehyde (7) from comparisons of their physicochemical and spectroscopic data 1H-, 13C-NMR, two-dimentioal NMR, and mass spectrometery) with those of authentic samples and reference data. This is the first report on the isolation of compounds 1–7 from T. quinquecostatus var. japonica. In addition, compounds 2 and 4 exhibited the most potent pancreatic lipase inhibitory activities in a concentration-dependent manner with IC50 values of 15.4±0.8 and 62.8±2.7 μM, respectively.

Qualitative and quantitative analysis of the major constituents in Chinese medicinal preparation Guan-Xin-Ning injection by HPLC–DAD–ESI-MS n

Guan-Xin-Ning (GXN) injection, a traditional Chinese medicinal preparation consisting of Radix Salvia miltiorrhiza and Rhizoma Ligusticum chuanxiong, has been used to treat coronary heart disease and angina pectoris in China for decades. In this paper, a HPLC/DAD/ESI-MS n method was successfully developed for qualitative and quantitative analysis of the active components in GXN injection for the first time. 28 compounds were identified by comparison of their retention times and MS spectra (HPLC/DAD/ESI-MS n ) with those elucidated standards or recorded literature. 19 of them (danshensu, furoic acid, 3- O-caffeoylquinic acid, protocatechuic aldehyde, p-hydroxybenzoic acid, chlorogenic acid, caffeic acid, 4- O-caffeoylquinic acid, vanillin, 1,3-dicaffeoylquinic acid, 4-hydroxycinnamic acid, ferulic acid, senkyunolide I, senkyunolide H, isosalvianolic acid A, rosmarinic acid, salvianolic acid B, salvianolic acid A and isosalvianolic acid C) were simultaneously determined by HPLC–DAD quantitatively. The analytical method was validated and successfully applied for simultaneous determination of major components in GXN injections from seven different production batches, indicating that the proposed approach was applicable for the routine analysis and quality control of GXN injection.

A quantitative method for simultaneous assay of five ingredients with one marker in Salvia miltiorrhiza

To establish a new quantitative method for simultaneous determination of multi-components in Salvia miltiorrhiza by using one chemical reference substance and validate its feasibilities. The new quality evaluation method, quantitative analysis of multi-components by singer-marker (QAMS), was established and validated with S. miltiorrhiza . Five main ingredients were selected as analytes to evaluate the quatity and their relative correlation factors (RCF) were determined by HPLC-DAD. Within the linear range, the values of RCF at 280 nm of sodium danshensu to protocatechuic aldehyde, rosmarinic acid, lithospermic acid and salvianolic acid B were 7.559, 2.901, 1.825 and 1.746, respectively. The contents of danshensu in the samples of S. miltiorrhiza were determined by using the external standard method, and the contents of the four other ingredients were calculated by their RCFS. The contents of these four ingredients in all samples were also determined by the external standard method. Within a certain range, the RCFs showed good reproducibility (RSD 1.0%-2.5%). No significant differences were observed between the quantitative results of the two methods. It is feasible and suitable to evaluate the quality of S. miltiorrhiza and its processed products by QAMS.

Simultaneous quantification of selected compounds from Salvia herbs by HPLC method and their application

A simple and reliable reversed-phase high performance liquid chromatographic method was developed and validated for simultaneous determination of danshensu, protocatechuic aldehyde, rosemarinic acid, salvianolic acid B, dihydrotanshinone I, tanshinone I, cryptotanshinone and tanshinone IIA in Salvia herbs. The contents of these eight main components were compared between Salvia miltiorrhiza Bunge and Salvia przewalskii Maxim, which were used for treating coronary heart diseases, cerebrovascular disease, bone loss, hepatitis, hepatocirrhosis and chronic renal failure. The samples were successfully separated by the HPLC method. All the standard compounds showed a good linearity (R2>0.9994) in the relatively wide concentration range. The limit of detection of the eight compounds was in the range of 0.05–0.5μg/ml and the limit of quantification was in the range of 0.25–1.50μg/ml. The intra-day variability was in the range of 0.03–8.08% and the inter-day variability was in the range of 0.18–12.36%. The recoveries of the selected compounds were in the range of 96.2–108.1%. This method was accurate, precise and reproducible, and could be successfully applied to the quality control and stable experiment for the preparations consisted of these active components, and the content comparison of the herbs from Salvia species.

Simultaneous Determination of Six Phenolic Constituents of Danshen Injection in Rat Plasma by Liquid Chromatography—Electrospray Ionization—Mass Spectrometry and its Application to a Pharmacokinetic Study

Salvianolic acid A, salvianolic acid B, danshensu, protocatechuic aldehyde, rosmarinic acid and lithospermic acid are the six major active constituents in Danshen injection. In this study, a rapid, sensitive and specific liquid chromatographic-electrospray ionization-mass spectrometry method for the simultaneous quantitative determination of these compounds in rat plasma was developed. After a single step of liquid-liquid extraction with ethyl acetate, they were eluted by a Hypersil C18 column (5 µm, i.d. 4.6 × 200 mm) within 4 min with a mobile phase consisting of acetonitrile and 0.1% formic acid water solution (35:65, v/v). The assay was linear in the concentration range of 0.05-10 µg mL(-1). Absolute recoveries were above 60%. The precisions and accuracies determined within three consecutive days were within acceptable limits. The method was successfully applied to a pharmacokinetic study in rats after an intravenous administration of Danshen injection.

Simultaneous quantitative determination of 9 active components in traditional Chinese medicinal preparation ShuangDan oral liquid by RP-HPLC coupled with photodiode array detection

A simple, accurate and reliable method for the simultaneous separation and determination of 9 active components (danshensu, protocatechuic acid, protocatechuic aldehyde, caffeic acid, rosmarinic acid, salvianolic acid B, paeonol, paeoniflorin and gallic acid) in traditional Chinese medicinal preparation ShuangDan (SD) oral liquid was developed using reverse phase high-performance liquid chromatography (RP-HPLC) coupled with photodiode array (PDA) detection. The chromatographic separation was performed on a SinoChrom ODS-BP C 18 column with gradient elution using methanol (A) and 3% glacial acetic acid aqueous solution (B) at a flow rate of 1.0 mL min −1, and with a PDA detection. Good linear behaviors over the investigated concentration ranges were observed with the values of r 2 higher than 0.9992 for all the analytes. The recoveries and relative standard deviation (RSD), measured at three concentration levels, varied from 98.21% to 101.82% and 0.07% to 1.37%, respectively. The proposed method enables the simultaneous identification and determination of 9 active components in a single run for the quality control of ShuangDan oral liquid.

Development of fluorescence imaging-based assay for screening cardioprotective compounds from medicinal plants

Medicinal plants have been widely recognized as a renewable resource for the discovery of novel leads and drug. In this study, an approach for screening and identification compounds with cardioprotective activity from medicinal plant extracts by cellular-fluorescence imaging technique was developed. It is a cell-based assay for measuring mitochondrial membrane potential changes in H9c2 cardiac muscle cells exposed to H 2O 2 by using a fluorescence automatic microscopy screening platform. Rhodamine 123 was used as the fluorescent dye to indicate the change of mitochondrial membrane potential. The sensitivity and linear range of the proposed approach were evaluated and validated using vitamin C, an antioxidative compound. The method was applied to screen active components with potent cardioprotective effects from a traditional Chinese formula. The potential cardioprotective components were identified by liquid chromatography coupled with mass spectrometry (LC/MS). Moreover, the utility of the proposed approach was further validated by three compounds (salvianolic acid B, protocatechuic aldehyde, and tanshinone II A) identified from the formula which showed cardioprotective effects in a dose-dependent manner. These applications suggested that the proposed rapid and sensitive screening approach offers an efficient way to discover active components or compounds from medicinal plants.

Capillary electrophoresis with field-enhanced stacking for determination of Water-Soluble Active Principles in Salvia miltiorrhiza var. miltiorrhiza f. alba

A simple and sensitive capillary electrophoresis method with field-enhanced stacking concentration for the analysis of protocatechuic aldehyde, protocatechuic acid, danshensu, rosmarinic acid and salvianolic acid B in Salvia miltiorrhiza var. miltiorrhiza f. alba was developed. The separation was achieved with a fused-silica capillary (75 microm x 50.2 cm, effective length was 40 cm) and a running buffer 15 mmol x L(-1) borax (pH 10.0) containing 20% CH3 OH. The UV detection wavelength was 210 nm. The applied voltage was 28 kV, and the cartridge temperature was 25 degrees C. Water plug was introduced from the anode by 0.5 psi x 4 s before injection. Sample was injected by electrokinetic injection - 8 kV x 3 s. The linear range of protocatechuic aldehyde is 3.0-60.00 mg x L(-1) (R2 = 0.999 8); that of protocatechuic acid, danshensu, rosmarinic acid and salvianolic acid B are 1.0-20.00 mg x L(-1) (R2 are 0.999 1, 0.999 4, 0.998 9 and 0.999 8, respectively), and the limits of detection of five analyts are 0.55, 0.40, 0.25, 0.32, 0.38 microg x L(-1), respectively, Stacking factor is higher and precision is satisfactory. The recoveries ranges were from 97.3% to 99.8%. The proposed method was used to determine the protocatechuic aldehyde, protocatechuic acid, danshensu, rosmarinic acid and salvianolic acid B in S. miltiorrhiza var. miltiorrhiza f. alba. The proposed method is simple, rapid, accurate and high sensitivity, and can be used to control of the quality of S. miltiorrhiza var. miltiorrhiza f. alba.

Characterization and Evaluation of Binding Properties of Salvianolic Acid a Imprinted Polymers Prepared by Precipitation Polymerization

Molecularly imprinted polymers (MIPs) were synthesized by precipitation polymerization using salvianolic acid A (Sal A), acrylamide (AA), ethylene glycol dimethacrylate (EGDMA) and acetonitrile as template molecule, functional monomer, cross-linker and solvent, respectively. The morphology of the obtained polymers was characterized by scanning electron microscopy (SEM). The effect of different polymerization conditions (solvent volume, solvent and template amount) on the size and shape of particles was investigated. The binding properties of the imprinted polymers were evaluated through the equilibrium rebinding experiments. Scatchard analysis revealed that two classes of binding sites were formed in the imprinted polymers with equilibrium dissociation constants of 0.33 μmol·mL-1 and 0.07 μmol·mL-1, respectively. Besides Sal A, two structurally related compounds, protocatechuic aldehyde (Pra) and salvianolic acid B (Sal B), were employed for molecular selectivity tests. The results indicated that the imprinted polymers exhibited good selectivity and specificity toward Sal A.

Study on the interaction of CdTe quantum dots with ferulic acid and protocatechuic aldehyde by optical spectroscopy

Luminescent CdTe quantum dots (QDs) were synthesized using thioglycolic acid (TGA) as a stabilizing agent in aqueous medium and were characterized by Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and transmission electron microscopy (TEM). In weak basic media the fluorescence of TGA–CdTe QDs was quenched notably by ferulic acid (FA) and protocatechuic aldehyde (PA), and the quenching values were proportional to the concentration of the quenchers in a certain range. The addition of bovine serum albumin (BSA) to TGA–CdTe QDs–FA and TGA–CdTe QDs–PA systems rendered a large recovery of the fluorescence of TGA–CdTe QDs.

Pharmacokinetics of phenolic compounds of Danshen extract in rat blood and brain by microdialysis sampling

To evaluate the pharmacokinetics of phenolic compounds after oral administration of Danshen extract in rat brain. Blood and brain microdialysis probes were inserted into jugular vein and cerebral cortex of rat under anesthesia and perfused with ringer's solution at the rate of 2.0 and 0.8 μL/min, respectively. Blank microdialysates were collected after 2h post-implantation equilibrium time. Danshen extract (danshensu 40 mg/kg BW, protocatechuic aldehyde 149 mg/kg BW, and salvianolic acid B 50mg/kg BW) was administrated intragastrically, and then blood and brain microdialysates were collected at 15 and 30 min time intervals for 4h, respectively. The concentrations of phenolic compounds were determined by high-performance liquid chromatography coupled with chemiluminescence detection. Pharmacokinetic parameters were estimated using non-compartmental methods. Danshensu and protocatechuic acid could be detected in both blood and brain microdialysates, while protocatechuic aldehyde and salvianolic acid B were not detected. Brain-to-blood (AUC(brain)/AUC(blood)) distribution ratio were 0.25±0.04 and 0.09±0.02 for danshensu and protocatechuic acid, respectively. Danshensu can readily permeate the blood brain barrier after oral administration of Danshen extract, and protocatechuic acid is a potential oxidative metabolite of protocatechuic aldehyde.

Pharmacokinetics of three phenolic acids of Xiangdan injection in rats

To establish a HPLC method for the analysis of Danshensu (DSS), protocatechuic acid (PA) and protocatechuic aldehyde (PAL) of Xiangdan injection in rat's plasma, and to study pharmacokinetic characteristics of Xiangdan injection components in rats with m-hydroxybenzoic acid as internal standard. protein was precipitated by 10% trichloroacetic acid and extracted by ethyl acetate. The plasma concentration was detected by HPLC, The pharmacokinetics parameters of DSS, PA and PAL were calculated by DAS2.0 software after iv injection. DSS, PA and PAL have a good linear relationship in 0.68-44.0 mg x L(-1), 0.43-14.0 mg x L(-1) and 0.38-12.0 mg x L(-1), respectively. The average recoveries were more than 92% and the RSD of precision and stability of the test were between 0.4%-4.8%. DSS, PA and PAL showed a two-compartment open model, the half-life of absorption (t(1/2alpha)) were (6.26 +/- 4.6), (5.93 +/- 4.9), (18.44 +/- 2.4) min, the half-life of elimination (t(1/2beta)) were (64.11 +/- 8.8), (63.28 +/- 0.13), (69.315 +/- 0) min, the area under curve(AUC(0-infinity)) were (852.98 +/- 175.6), (83.84 +/- 58.8), (147.79 +/- 12.3) mg x min(-1) x L(-1). A method with high recovery rate and good stability was established to determine the blood concentration of DSS, PA, PAL in Xiangdan injection and applied in its pharmacokinetics successfully.

Effect of Toasting Intensity at Cooperage on Phenolic Compounds in Acacia (Robinia pseudoacacia) Heartwood

The phenolic composition of heartwood from Robinia pseudoacacia, commonly known as false acacia, before and after toasting in cooperage was studied by HPLC-DAD and HPLC-DAD/ESI-MS/MS. A total of 41 flavonoid and nonflavonoid compounds were identified, some tentatively, and quantified. Seasoned acacia wood showed high concentrations of flavonoid and low levels of nonflavonoid compounds, the main compounds being the dihydroflavonols dihydrorobinetin, fustin, tetrahydroxy, and trihydroxymethoxy dihydroflavonol, the flavonol robinetin, the flavanones robtin and butin, and a leucorobinetinidin, none of which are found in oak wood. The low molecular weight (LMW) phenolic compounds present also differed from those found in oak, since compounds with a β-resorcylic structure, gallic related compounds, protocatechuic aldehyde, and some hydroxycinnamic compounds are included, but only a little gallic and ellagic acid. Toasting changed the chromatographic profiles of extracts spectacularly. Thus, the toasted acacia wood contributed flavonoids and condensed tannins (prorobinetin type) in inverse proportion to toasting intensity, while LMW phenolic compounds were directly proportional to toasting intensity, except for gallic and ellagic acid and related compounds. Even though toasting reduced differences between oak and acacia, particular characteristics of this wood must be taken into account when considering its use in cooperage: the presence of flavonoids and compounds with β-resorcylic structure and the absence of hydrolyzable tannins.

민들레 뿌리로부터 Pancreatic lipase 저해 물질의 분리

Activity-guided isolation from an ethylacetate-soluble fraction of a 70% (v/v) ethanolic extract from the roots of Taraxacum ohwianum, using a pancreatic lipase inhibition assay, resulted in isolation and identification of five phenolic metabolites of previously known structure; these were 3,5-di-O-caffeoylquinic acid, chicoric acid, caffeic acid, protocatechuic aldehyde, and luteolin. All structures were confirmed by NMR and MS scpectroscopic data. Of these compounds 3,5-di-O-caffeoylquinic acid exhibited the most potent inhibitory activity, with of against pancreatic lipase.

Rapid identification and determination of 11 polyphenols in Herba lycopi by HPLC–MS/MS with multiple reactions monitoring mode (MRM)

A new and rapid method was developed for simultaneous identification and determination of 11 polyphenols in Herba lycopi, i.e. rosmarinic acid, protocatechuic aldehyde, protocatechuic acid, caffeic acid, ferulic acid, apigenin, luteolin, quercetin, isorhamnetin, chlorogenic acid and rutin, using high performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry (MS/MS). Quantitation was based on multiple reactions monitoring (MRM) using the precursor→production combination for the determination of 11 analytes. The analysis was performed on an Eclipse Plus C18 column (I.D. 4.6mm×100mm, 3.5μm particle size). An electrospray ionization (ESI)-tandem interface in the negative mode was employed prior to mass spectrometric detection. With the optimized conditions, the 11 biomarkers were detected properly within 3min. Limits of detection (LOD) ranged from 0.6 to 2.6ng/ml. The average recoveries ranged from 95.42 to 101.11% with RSDs≤2.23%. The applicability of this analytical approach was confirmed by the successful analysis of 3 samples. The established method was validated and found to be sensitive and reliable for the determination of 11 analytes in Herba lycopi.

DJ-1–Mediated Protective Effect of Protocatechuic Aldehyde Against Oxidative Stress in SH-SY5Y Cells

DJ-1 was identified as a causal gene for a familial form of early onset Parkinson’s disease (PD), park 7. DJ-1 plays roles in transcriptional regulation and the anti-oxidative stress reaction. In this study, we found that protocatechuic aldehyde (PAL), a traditional Chinese medicine compound, bound to DJ-1 in vitro and that PAL protected SH-SY5Y cells but not DJ-1–knockdown SH-SY5Y cells from oxidative stress–induced cell death, indicating that the protective effect of PAL is mediated by DJ-1. Furthermore, PAL inhibited production of reactive oxygen species and the inhibition was abated in DJ-1–knockdown cells. PAL increased and decreased phosphorylation of AKT and PTEN, respectively, in SH-SY5Y cells, suggesting that the AKT pathway is one of the specific signaling pathways in PAL-induced neuroprotection. Moreover, PAL prevented superfluous oxidation of cysteine 106 of DJ-1, an essential amino acid for DJ-1’s function. The present study demonstrates that PAL has potential neuroprotective effects through DJ-1.

The interaction between protocatechuic aldehyde and human serum albumin using three-dimensional fluorescence techniques

The binding mechanism between protocatechuic aldehyde (PA) and human serum albumin (HSA) was investigated by fluorescence spectroscopy at different temperatures. It is proved that the fluorescence quenching of HSA by PA is not results of the formation of PA–HSA complex. The equilibrium constantKand the number of binding sitesnwere measured at different temperature by fluorescence quenching method. The standard enthalpy change (ΔH) and the standard entropy change (ΔS) of this interaction process were calculated to be 114.02 kJ · mol−1, 541.92 J · mol−1·K−1, respectively. According to the interaction between PA and HSA of thermodynamic parameters ΔHand ΔS, the major acting force can be measured. The synchronous fluorescence spectra shows the microenvironment of tryptophan residue is changed and the hydrophobicity is increased. Through three-dimensional (3D) fluorescence spectra can get some valuable structure changing information.

The interaction between protocatechuic aldehyde and human serum albumin using three-dimensional fluorescence techniques

The binding mechanism between protocatechuic aldehyde (PA) and human serum albumin (HSA) was investigated by fluorescence spectroscopy at different temperatures. It is proved that the fluorescence quenching of HSA by PA is not results of the formation of PA-HSA complex. The equilibrium constant K and the number of binding sites n were measured at different temperature by fluorescence quenching method. The standard enthalpy change (ΔH) and the standard entropy change (ΔS) of this interaction process were calculated to be 114.02 kJ · mol −1 , 541.92 J · mol −1 · K −1 , respectively. According to the interaction between PA and HSA of thermodynamic parameters ΔH and ΔS, the major acting force can be measured. The synchronous fluorescence spectra shows the microenvironment of tryptophan residue is changed and the hydrophobicity is increased. Through three-dimensional (3D) fluorescence spectra can get some valuable structure changing information.

Dialysis sampling on-line coupled with high-performance liquid chromatography for simultaneous investigation of the interactions between multi-components in herbs and the albumin

An on-line dialysis sampling method coupled with high-performance liquid chromatography was developed for simultaneous investigation of the interactions between multiple bioactive compounds contained in herbal medicines and proteins. The system was used to estimate the interactions of components in danshen (Salvia miltiorrhiza) injection with bovine serum albumin. The results showed that the binding actions of five water-soluble compounds in danshen injection could be simultaneously investigated. The binding parameters of caffeic acid, ferulic acid, danshensu, protocatechuic acid and protocatechuic aldehyde were obtained and the interaction mechanisms were explored. The association constant evaluated for caffeic acid agreed well with literature values. The proposed approach should be beneficial for examining the holistic combined action of herbal medicine with proteins and help facilitate the discovery process of drug candidates.

Peroxidase-Catalyzed Synthesis of Polyphenols Bearing Aldehyde Units

It is already known that phenolic monomers bearing electron-withdrawing groups could hardly be polymerized by oxireductases. In this paper, enzymatic polymerization (EP) of phenolic monomers possessing electron-withdrawing aldehyde side-groups, protocatechualdehyde (PCA) and pyrogallolaldehyde (PGA), is presented. The monomers were converted to their polymers via enzyme-catalyzed oxidative polymerization in buffered-dioxane solution using horseradish peroxidase as the catalyst and hydrogen peroxide as the oxidant. The resulting products (abbreviated as PPCA and PPGA) were characterized by means of UVVis, FT-IR, 1H-NMR, GPC (gel-permeation chromatography), TG–DTA and DSC analyses. IR and NMR data indicated that the obtained polymers consisted of a mixture of phenylene/oxyphenylene units, and the aldehyde (–CH=O) side-groups in the polymer chains were not oxidized. The electrical and electrochemical characterizations of the polymers were performed by solid-state conductivity and cyclic voltammetry (CV) techniques, respectively. Fluorescence analyses of PGA and PPGA were also conducted in DMSO. Emission maxima of PPGA were red shifted by nearly 34 nm compared to its monomer.