Structural characterization of metabolites of salvianolic acid B from Salvia miltiorrhiza in normal and antibiotic-treated rats by liquid chromatography–mass spectrometry

Gut microbiota: a superior operator for dietary phytochemicals to improve atherosclerosis

Mounting evidence implicates the gut microbiota as a possible key susceptibility factor for atherosclerosis (AS). The employment of dietary phytochemicals that strive to target the gut microbiota has gained scientific support for treating AS. This study conducted a general overview of the links between the gut microbiota and AS, and summarized available evidence that dietary phytochemicals improve AS via manipulating gut microbiota. Then, the microbial metabolism of several dietary phytochemicals was summarized, along with a discussion on the metabolites formed and the biotransformation pathways involving key gut bacteria and enzymes. This study additionally focused on the anti-atherosclerotic potential of representative metabolites from dietary phytochemicals, and investigated their underlying molecular mechanisms. In summary, microbiota-dependent dietary phytochemical therapy is a promising strategy for AS management, and knowledge of "phytochemical-microbiota-biotransformation" may be a breakthrough in the search for novel anti-atherogenic agents.

Metabolism of phenolics in coffee and plant-based foods by canonical pathways: an assessment of the role of fatty acid β-oxidation to generate biologically-active and -inactive intermediates

ω-Phenyl-alkenoic acids are abundant in coffee, fruits, and vegetables. Along with ω-phenyl-alkanoic acids, they are produced from numerous dietary (poly)phenols and aromatic amino acids in vivo. This review addresses how phenyl-ring substitution and flux modulates their gut microbiota and endogenous β-oxidation. 3',5'-Dihydroxy-derivatives (from alkyl-resorcinols, flavanols, proanthocyanidins), and 4'-hydroxy-phenolic acids (from tyrosine, p-coumaric acid, naringenin) are β-oxidation substrates yielding benzoic acids. In contrast, 3',4',5'-tri-substituted-derivatives, 3',4'-dihydroxy-derivatives and 3'-methoxy-4'-hydroxy-derivatives (from coffee, tea, cereals, many fruits and vegetables) are poor β-oxidation substrates with metabolism diverted via gut microbiota dehydroxylation, phenylvalerolactone formation and phase-2 conjugation, possibly a strategy to conserve limited pools of coenzyme A. 4'-Methoxy-derivatives (citrus fruits) or 3',4'-dimethoxy-derivatives (coffee) are susceptible to hepatic "reverse" hydrogenation suggesting incompatibility with enoyl-CoA-hydratase. Gut microbiota-produced 3'-hydroxy-4'-methoxy-derivatives (citrus fruits) and 3'-hydroxy-derivatives (numerous (poly)phenols) are excreted as the phenyl-hydracrylic acid β-oxidation intermediate suggesting incompatibility with hydroxy-acyl-CoA dehydrogenase, albeit with considerable inter-individual variation. Further investigation is required to explain inter-individual variation, factors determining the amino acid to which C6-C3 and C6-C1 metabolites are conjugated, the precise role(s) of l-carnitine, whether glycine might be limiting, and whether phenolic acid-modulation of β-oxidation explains how phenolic acids affect key metabolic conditions, such as fatty liver, carbohydrate metabolism and insulin resistance.

Dissection of the potential anti-diabetes mechanism of salvianolic acid B by metabolite profiling and network pharmacology

RATIONALE

Salvianolic acid B (Sal B), the Q-marker in Salvia miltiorrhiza, was proved to present an obvious anti-diabetes effect when treated as a food intake. Until now, the metabolism feature, tissue distribution and anti-diabetes mechanism of Sal B have not been fully elucidated.

METHODS

The metabolites of Sal B in rats were profiled using ultrahigh-performance liquid chromatography coupled with time-of-flight mass spectrometry. The potential anti-diabetes mechanism of Sal B was predicted by network pharmacology.

RESULTS

A total of 31 metabolites were characterized in rats after ingestion of Sal B at a dosage of 40 mg/kg, including 1 in plasma, 19 in urine, 31 in feces, 0 in heart, 0 in liver, 0 in spleen, 1 in lung, 1 in kidney and 0 in brain. Among them, 18 metabolites were reported for the first time. Phase I reactions of hydrolysis, hydrogenation, dehydroxylation, hydroxylation, decarboxylation and isomerization, and phase II reactions of methylation were found in Sal B. Notably, decarboxylation and dehydroxylation were revealed in Sal B for the first time. The pharmacology network results showed that Sal B and its metabolites could regulate ALB, PLG, ACE, CASP3, MMP9, MMP2, MTOR, etc. The above targets were involved in insulin signaling pathway, PI3K-Akt signaling pathway, HIF-1 signaling pathway, TNF signaling pathway, etc. CONCLUSIONS: The metabolism feature of Sal B in vivo was systematically revealed, and its anti-diabetes mechanism for further pharmacological validations was predicted based on metabolite profiling and network pharmacology for the first time.

Investigation of the metabolites of five major constituents from Berberis amurensis in normal and pseudo germ-free rats

Berberis amurensis (Berberidaceae) is a traditional Chinese medicine, which is often used to treat hypertension, inflammation, dysentery and enteritis. It contains alkaloids, mainly including berberine, berbamine, magnoflorine, jatrorrhizine and palmatine. Berberis amurensis extracts (BAEs) is often orally taken. Oral herbs might be metabolized by intestinal bacteria in the small intestine. However, the interaction between the herb and the gut microbiota is still unknown. In the current study, UPLC/Q-TOF-MS/MS combined with Metabolitepilot and Peakview software was used to identify the metabolites of BAEs in anti-biotic cocktail induced pseudo germ-free rats and normal rats. As a result, a total of 46 metabolites in normal rats were detected and its main metabolic pathways include demethylation, dehydrogenation, methylation, hydroxylation, sulfation and glucuronidation. Only 29 metabolites existed in pseudo germ-free rats. Dehydrogenated metabolites (M29, M30, M34 and M36), methylated metabolites (M33, M41 and M46) and other metabolites were not detected in pseudo germ-free rats. The result implied that the intestinal bacteria have an influence on the metabolism of BAEs. Furthermore, this investigation might contribute to the understanding of the metabolism of BAEs, and further promote its clinical application.

The Metabolism of Tanshinone IIA, Protocatechuic Aldehyde, Danshensu, Salvianolic Acid B and Hydroxysafflor Yellow A in Zebrafish

Background:

Tanshinone IIA (TIIA), protocatechuic aldehyde (PA), danshensu (DSS), salvianolic acid B (SAB) and hydroxysafflor yellow A (HSYA) are the major components of Salvia miltiorrhiza Bge. (Danshen) and Carthamus tinctorius L. (Honghua) herbal pair. These active components may contribute to the potential synergistic effects of the herbal pair.

Objective:

This study aimed to investigate the metabolites of TIIA, PA, DSS, SAB and HSYA in zebrafish, and to explore the influence of HSYA on the metabolism of TIIA, PA, DSS, and SAB.

Method:

48 h post-fertilization zebrafish embryos were exposed either to each compound alone, TIIA (0.89 μg/mL), PA (0.41 μg/mL), DSS (0.59 μg/mL), SAB (2.15 μg/mL), and HSYA (1.83 μg/mL) and in combination with HSAY (1.83 μg/mL). The metabolites of TIIA, PA, DSS, SAB, and HSYA in zebrafish were characterized using high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) and quantitatively determined by HPLC-MS with single and combined exposure.

Results:

Among the 26 metabolites detected and characterized from these five compounds, methylation, hydroxylation, dehydrogenation, hydrolysis, sulfation and glucuronidation were the main phase I and phase II metabolic reactions of these compounds, respectively. Furthermore, the results showed that HSYA could either enhance or reduce the amount of TIIA, PA, DSS, SAB, and their corresponding metabolites.

Conclusion:

The results provided a reference for the study on drug interactions in vivo. In addition, the zebrafish model which required much fewer amounts of test samples, compared to regular mammal models, had higher efficiency in predicting in vivo metabolism of compounds.

Pharmacokinetic Comparisons of Different Combinations of Yigan Jiangzhi Formula in Rats: Simultaneous Determination of Fourteen Components by UPLC-MS/MS

A rapid, specific, and sensitive analysis for simultaneous determination of fourteen components (daidzein, fermononetin, apigenin, luteolin, puerarin, ononin, calycosin-7-O-β-D-glucoside, tanshinol, rosmarinic acid, alkanoic acid, salvianolic acid B, berberine, jatrorrhizin, and palmatine) of Yigan Jiangzhi formula (YGJZF, a clinical experienced formula for damp-heat syndrome) in rat plasma was developed and validated using ultraperformance liquid chromatography coupled with mass spectrometry. Lower limit of quantitation ranged from 0.2-10.0 ng/mL, and the calibration curves showed good linearity over 500 times of measuring range. The validated method was successfully applied to the pharmacokinetics investigation of the fourteen compounds in rat plasma after oral administration of two different doses of YGJZF. Compared with the low-dose group of YGJZF, the high-dose group showed significant increase (P < 0.01 or P < 0.05) in maximum plasma concentration, maximum concentration time, and area under the plasma concentration-time curve and decrease (P < 0.01 or P < 0.05) in clearance of most of the fourteen analytes, which suggested that the bioavailability of these components could be enhanced by increasing dosage. The above results may provide useful information for cognizing the relationship between in vitro and in vivo data of the fourteen bioactive ingredients of YGJZF and further guiding rational clinical drug prescription.

Oxidative metabolism of typical phenolic compounds of Danshen by electrochemistry coupled to quadrupole time-of-flight tandem mass spectrometry

An electrochemistry coupled to online quadrupole time-of-flight tandem mass spectrometry (EC/Q-TOF/MS) was applied to investigate the oxidative transformation and metabolic pathway of five phenolic acids in Danshen sample. Simulation of the phase I oxidative metabolism was carried out in an electrochemical reactor equipped with a glassy carbon working electrode. The phase II reactivity of the generated oxidative products towards biomolecules (such as glutathione) was investigated by ways of covalent adduct formation experiments. The results obtained by EC/MS were compared with well-known in vitro studies by conducting rat liver microsome incubations. Structures of the electrochemically produced metabolites were identified by accurate mass measurement and previously results in vivo metabolites. It was indicated that the electrochemical oxidation was in good accordance with similar products found in vivo experiments. In conclusion, this work confirmed that EC/Q-TOF/MS was a promising analytical tool in the prediction of metabolic transformations of functional foods.

Chemical and pharmacological research on the polyphenol acids isolated from Danshen: A review of salvianolic acids

Danshen, the dried root of Salvia miltiorrhiza Bge, is a common medicinal herb in Traditional Chinese Medicine, which has been used for the treatment of a number of diseases for thousands of years. More than 2000 years ago, the Chinese early pharmacy monograph "Shennong Materia Medica" recorded that Danshen could be used for the treatment of gastrointestinal diseases, cardiovascular diseases, certain gynecological diseases, etc. Since then, Danshen has been widely used clinically in many different prescriptions for many different diseases, especially for the treatment of cardiovascular diseases. Nowadays, many pharmacological studies about the water-soluble components from Danshen have been reported, especially salvianolic acids. It turned out that salvianolic acids showed strong anti-lipid peroxidation and anti-thrombic activities, and among them, SalAA and SalAB were the most potent. This review focused on the achievements in research of salvianolic acids regarding their bioactivities and pharmacological effects. These studies not only shed light on the water-soluble active components of Danshen and their mechanisms at the molecular level, but also provided theoretical information for the development of new medicines from Danshen for the treatment of cardiovascular and cerebrovascular diseases, inflammatory diseases, metabolic diseases, etc.

Systematic screening and characterization of Qi-Li-Qiang-Xin capsule-related xenobiotics in rats by ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry

Qi-Li-Qiang-Xin capsule (QLQX), a well-known traditional Chinese medicine prescription (TCMP), is consisted of eleven commonly used herbal medicines, has been widely used for the treatment of chronic heart failure (CHF). However, the absorbed components and related metabolites after oral administration of QLQX are still remaining unknown. In the present work, a reliable and effective method using ultra performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS) was established to identify QLQX-related xenobiotics in rats. Based on a representative structure based homologous xenobiotics identification (RSBHXI) strategy, a total of eleven compounds (salvianolic acid B, formononetin, benzoylmesaconine, alisol A, sinapine thiocyanate, naringin, tanshinone IIA, ginsenoside Rg1, ginsenoside Rb1, astragaloside IV and periplocin), bearing different chemical core structures, were selected and investigated for their metabolism in vivo. And then, comprehensive metabolic profiles of the holistic multi-ingredients in QLQX were achieved. As a result, a total of 121 QLQX-related xenobiotics (47 prototypes and 74 metabolites) were identified or tentatively characterized, among them eight prototypes (mesaconine, hypaconine, songorine, fuziline, neoline, talatizamine formononetin, neocryptotanshinone) and two metabolites (calycosin-gluA, formononetin-guA) were relatively the main existing xenobiotics exposed in blood. All absorbed prototype constituents were mainly from six composed herbal medicines (Aconiti lateralis radix, Astragali radix, Ginseng radix, Alismatis rhizoma, Salvia miltiorrhiza radix, Periploca cortex). The main metabolic reactions were methylation, hydrogenation, hydroxylation, oxidization, sulfation and glucuronidation. This is the first study on in vivo metabolism of QLQX. These results enabled us to focus on several high exposure ingredients in the discovery of effective substances of QLQX, however further pharmacokinetic study on these QLQX-related xenobiotics are needed to be carried out.

Rapid characterization of the absorbed chemical constituents of Tangzhiqing formula following oral administration using UHPLC-Q-TOF-MS

Tangzhiqing formula, a Chinese herbal formula, is used for the treatment of type II diabetes and prediabetes. Although its effectiveness has been certified by clinical use, its absorbed chemical constituents are not comprehensively represented. Thence, in order to reveal potential bioactive components and metabolism of Tangzhiqing formula, an ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry method was developed. A total of 86 absorbed components, including 38 prototype compounds and 48 metabolites, were identified in rat plasma, urine, and feces after oral administration of Tangzhiqing formula. This was the first systematic study on the chemical constituents and metabolic profiling of Tangzhiqing formula. The results indicated that alkaloids and flavonoids were main absorbed components, and glucuronidation and sulfation were the major metabolites. Moreover we concluded that alkaloids and flavonoids first underwent demethylation and hydrolysis reactions before biotransformed to phase II metabolites. This study provided valuable data for safety estimation of Tangzhiqing formula, which will be advantageous for clinical application.

Development and validation of an LC-MS/MS method for the simultaneous quantification of seven constituents in rat plasma and application in a pharmacokinetic study of the Zaoren Anshen prescription

A sensitive, specific and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of seven constituents of the Zaoren Anshen prescription (ZAP) in rat plasma after oral administration of the ZAP: spinosin, salvianic acid A, 6'''-feruloylspinosin, protocatechualdehyde, salvianolic acid B, schisandrin and deoxyschisandrin. The plasma samples and the internal standard (IS) sulfamethoxazole were extracted using acetonitrile. Chromatographic separation was performed with an Agilent HC-C₁₈ column using a gradient elution profile and a mobile phase consisting of 0.01% formic acid in water (A) and acetonitrile (B). The analytes were quantified simultaneously in a single run using an ion trap mass spectrometer operated in the multiple reaction monitoring mode and electrospray ion-source polarity in the positive and negative modes. The calibration curves for spinosin, salvianic acid A, 6'''-feruloylspinosin, protocatechualdehyde, salvianolic acid B, schisandrin and deoxyschisandrin were linear over the concentration ranges of 2.90-1160, 2.50-1000, 1.80-720, 0.65-260, 2.50-1000, 8.00-1600 and 1.30-520 ng/mL, respectively. The intra- and inter-day precisions in terms of relative standard deviation were <18.9%, and the accuracies in terms of relative error were within ±14.2%. Consequently, the proposed method was successfully applied to the pharmacokinetic analysis of these seven major active compounds in rats administered ZAP. These results will facilitate research aiming to predict the effectiveness of the optimal dose of ZAP and might be beneficial for the therapeutic use of ZAP in the clinical setting.

Quantitatively metabolic profiles of salvianolic acids in rats after gastric-administration of Salvia miltiorrhiza extract

Salvianolic acids, the well-known active components in Salvia miltiorrhiza, have been shown to possess markedly pharmacological activities. However, due to the complex in vivo course after administration, the pharmacologically active forms are still poorly understood. In present study, we evaluated the stability of eight major salvianolic acids from Danshen extract under different chemical and physiological conditions. We also quantitatively explained the absorption, metabolism and excretion of these salvianolic acids in rats after gastric-administration, which was carried out by simultaneously determining the amounts of salvianolic acids and their metabolites in the rat gastrointestinal contents, gastrointestinal mucosa, plasma, bile and urine. We found that: 1) protocatechuic aldehyde (PAL) was much stable whether in acidic environment (pH4.0) or in alkaline environment (pH8.0), while other salvianolic acids were stable in acidic environment and instable in alkaline environment; 2) PAL, salvianoli acid A (SAA) and salvianolic acid B (SAB) were instable whether in rat stomach or in small intestine, while other salvianolic acids were stable in rat stomach and instable in small intestine; 3) after gastric-administration, except PAL and Danshensu (DSS), other phenolic acids would be metabolized into DSS and caffeic acid (CA) in the rat gastrointestinal tract before absorption, and only free and glucuronidated PAL, CA and DSS were detected in rat plasma, bile and urine. In conclusion, it was the free and glucuronidated PAL, CA and DSS rather than the prototypes of other salvianolic acids that were present in plasma with considerable concentrations after gastric-administration.

Effect of salvianolic acid B on TNF-α induced cerebral microcirculatory changes in a micro-invasive mouse model

PURPOSE

To investigate the effects of salvianolic acid B (SAB) on tumor necrosis factor a (TNF-α) induced alterations of cerebral microcirculation with a bone-abrading model.

METHODS

The influences of craniotomy model and bone-abrading model on cerebral microcirculation were compared. The bone-abrading method was used to detect the effects of intracerebroventricular application of 40 μg/kg·bw TNF-α on cerebral venular leakage of fluorescein isothiocyanate (FITC)- albulmin and the rolling and adhesion of leukocytes on venules with fluorescence tracer rhodamine 6G. The therapeutical effects of SAB on TNF-α induced microcirculatory alteration were observed, with continuous intravenous injection of 5 mg/kg·h SAB starting at 20 min before or 20 min after TNF-α administration, respectively. The expressions of CD11b/CD18 and CD62L in leukocytes were measured with flow cytometry. Immunohistochemical staining was also used to detect E-selectin and ICAM-1 expression in endothelial cells.

RESULTS

Compared with craniotomy method, the bone-abrading method preserved a higher erythrocyte velocity in cerebral venules and more opening capillaries. TNF-α intervention only caused responses of vascular hyperpermeability and leukocyte rolling on venular walls, without leukocyte adhesion and other hemodynamic changes. Pre- or post-SAB treatment attenuated those responses and suppressed the enhanced expressions of CD11b/CD18 and CD62L in leukocytes and E-selectin and ICAM-1 in endothelial cells induced by TNF-α.

CONCLUSIONS

The pre- and post-applications of SAB during TNF-α stimulation could suppress adhesive molecular expression and subsequently attenuate the increase of cerebral vascular permeability and leukocyte rolling.

UPLC-Q-TOF/MS-based screening and identification of the main flavonoids and their metabolites in rat bile, urine and feces after oral administration of Scutellaria baicalensis extract

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese Medicines (TCMs) are increasingly used in combination with Western medicine. Scutellaria baicalensis Georgi (Lamiaceae) is a widely used TCM in treating various diseases. However, the in vivo metabolism of its main bioactive flavonoids, baicalin, baicalein, wogonoside and wogonin, needs further study.

MATERIALS AND METHODS

A systematic method based on ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) technique combined with Metabolynx(TM) software was developed to speculate the metabolites and excretion profiles of the main flavonoids in S. baicalensis extract in rats bile, urine and feces samples after oral administration of the extract.

RESULTS

Four parent components and a total of 15 metabolites were tentatively detected in vivo. All metabolites were detected including sulfate and glucuronide conjugates, hydroxylated, methylated, acetylated and deoxygenated products. Twelve metabolites were from the rat urine, five from the feces and two from the bile. Among them, several products were reported firstly.

CONCLUSION

The research provided useful information for further study of the pharmacology and mechanism of action of S. baicalensis extract in vivo and a proposed method which could develop an integrated template approach to analyze screening and identification of biological samples after oral administration of TCMs.

Development and validation of liquid chromatography-tandem mass spectrometry method for simultaneous determination of six steroidal saponins in rat plasma and its application to a pharmacokinetics study

A specific and reliable liquid chromatography-electrospray ionization-tandem mass spectrometry method was developed for the simultaneous determination of timosaponin H1 (TH1), timosaponin E1 (TE1), timosaponin E (TE), timosaponin B-II (TB-II), timosaponin B-III (TB-III) and anemarrhenasaponin I (AS-I) in rat plasma. After addition of internal standard (IS) ginsenoside Rh1, plasma samples were pretreated by protein precipitation with acetonitrile. Chromatographic separation was performed on a reverse phase ACQUITY™ BEH C18 column (100mm×2.1mm i.d., 1.7μm) using a gradient mobile phase system of acetonitrile-water containing 0.05% formic acid and 5mM ammonium formate. The triple quadruple mass spectrometer was set in negative electrospray ionization mode and multiple reaction monitoring (MRM) was used for six steroidal saponins quantification. The precursors to produce ion transitions monitored for TH1, TE1, TE, TB-II, TB-III, AS-I and IS were m/z 1211.5>1079.6, 935.5>773.4, 935.4>773.5, 919.6>757.4, 901.5>739.3, 757.4>595.3 and 637.3>475.3, respectively. The method validation was conducted over the curve range of 0.5-400ng/mL for the six saponins. The intra- and inter-day precisions (RSD%) were less than 9.4% and the average extraction recoveries ranged from 82.5% to 97.8% for each analyte. Six steroidal saponins were proved to be stable during sample storage, preparation and analytical procedures. The validated method was successfully applied for the first time to determine the concentrations of six main steroidal saponins in incurred rat plasma samples, after intragastric administration of the extract of Anemarrhena asphodeloides Bge. for a rat pharmacokinetic study.

Regulation of vascular endothelial genes by dietary flavonoids: structure-expression relationship studies and the role of the transcription factor KLF-2

Physiological concentrations (1 μM) of 15 flavonoids were evaluated in human umbilical vein endothelial cells in the presence of hydrogen peroxide (H₂O₂) for their ability to affect endothelial nitric oxide synthase (eNOS) and endothelin-1 (ET-1) expression in order to establish the structural basis of their bioactivity. Flavonoid effects on eNOS transcription factor Krüpple like factor-2 (KLF-2) expression were also evaluated. All studied flavonoids appeared to be effective compounds for counteracting the oxidative stress-induced effects on vascular gene expression, indicating that flavonoids are an excellent source of functional endothelial regulator products. Notably, the more effective flavonoids for KLF-2 up-regulation resulted in the highest values for eNOS expression, showing that the increment of eNOS expression would take place through KLF-2 induction. Structure-activity relationship studies showed that the combinations of substructures on flavonoid skeleton that regulate eNOS expression are made up of the following elements: glycosylation and hydroxylation of C-ring, double bond C2=C3 at C-ring, methoxylation and hydroxylation of B-ring, ketone group in C4 at C-ring and glycosylation in C7 of A-ring, while flavonoid features involved in the reduction of vasoconstrictor ET-1 expression are as follows: double bond C2=C3 at C-ring glycosylation in C7 of A-ring and ketone group in C4 of C-ring.

The identification and pharmacokinetic studies of metabolites of salvianolic acid B after intravenous administration in rats

AIM

To identify and quantify the major metabolites of salvianolic acid B (SAB) after intravenous injection in rats.

METHODS

LC-IT/TOF-MS was used to identify the metabolites in rat bile, plasma, and urine; LC-MS/MS was used to quantify the two major metabolites.

RESULTS

In rat bile, plasma, and urine, nine metabolites were identified, including methylated metabolites of SAB, lithospermic acid (LSA), the decarboxylation and methylation metabolites of LSA, salvianolic acid S (SAS), and dehydrated-SAS. The t1/2 of monomethyl-SAB and LSA were both very short, and monomethyl-SAB had a larger AUC than LSA in rats.

CONCLUSION

Nine metabolites were found, the metabolic pathway was described, and the pharmacokinetic profiles of LSA and monomethyl-SAB were studied, thereby clarifying that methylation was the dominant metabolic pathway for SAB in rats.

Alteration of bile acid metabolism in pseudo germ-free rats [corrected]

To characterize the impact of gut microbiota on host bile acid metabolism, we investigated the metabolic profiles of oxysterols and bile acids (BAs) in a conventional rat model (SD) (n=5) and its pseudo germ-free (GF) equivalent (n=5). GF rats were developed by the oral administration of bacitracin, neomycin and streptomycin (200 mg/kg, each) twice a day for 6 days. Urinary levels of oxysterols and bile acid metabolites were quantified using gas chromatography-mass spectrometry (GC-MS). The activity levels of enzymes involved in the bile acid metabolic pathway were determined through urinary concentration ratio between product to precursor. Cholic acid (CA) and α-/β-muricholic acid (α-/β-MCA) were significantly elevated at pseudo germ-free condition. An increase of hydroxylase (cholesterol 7α-hydroxylase, oxysterol 7α-hydroxylase and cytochrome P450 scc) and a significant decrease of 7α-dehydroxylase were observed. The urinary concentration ratio of primary bile acids, a marker for hepatotoxicity, increased in pseudo germfree conditions. Therefore, it was found that gut microbiota could play a significant role in the bile acids homeostasis and metabolism.

Analysis of the Constituents in Rat Serum after Oral Administration of Fufang Zhenzhu Tiaozhi Capsule by UPLC-Q-TOF-MS/MS

A rapid and sensitive UPLC/Q-TOF-MS method has been established for analysis of the constituents in rat serum after oral administration of Fufang Zhenzhu Tiaozhi (FTZ) capsule, an effective compound prescription for treating hyperlipidemia in the clinic. The UPLC/MS information of samples was obtained first in FTZ preparation and FTZ-treated rat serum. Mass spectra were acquired in both negative and positive ion modes. Thirty-six constituents in rat serum after oral administration of FTZ were detected, including the alkaloids, ginsenosides, pentacyclic triterpenes, and their metabolites. These chemicals were identified based on the retention time and mass spectrometry data with those of authentic standards or comparison of the literatures reports. Twenty-seven prototype components originated from FTZ and nine were the metabolites of the FTZ constituents. These results shed light on the potential active constituents of the complex traditional Chinese medicinal formulas.

Investigation of endogenous metabolic changes in the urine of pseudo germ-free rats using a metabolomic approach

Gut microflora are recognized as an active metabolic compartment in whole body systems. Understanding their impact on host physiology is an ongoing process, although many studies demonstrate that they play significant roles in host life. To assess the impact of gut microflora on host physiology in normal or close to normal conditions of the intestine, we prepared pseudo germ-free rats by antibiotic treatment, and we investigated urinary metabolite profiles of pseudo germ-free rats using UPLC-QTOF-MS based on metabolomics. The repeatability and stability of the analysis were evaluated using QC samples and testmixes in both positive and negative ionization modes. When data sets were analyzed with OPLS-DA, 25 metabolites related to the activities of gut microflora were identified. The changes of amino acid metabolism, especially aromatic or sulfur amino acids, and alternations of bioactive nutrients, such as isoflavonoid and riboflavin were observed in the pseudo germ-free rats. Among the sulfur amino acid metabolites, the metabolites reflecting oxidative stress increased in the urine of pseudo germ-free animals, which imply that the activities of intestinal microorganisms can affect the host redox homeostasis. Altered isoflavonoid metabolism due to lack of gut bacteria may impact on steroid hormone metabolism in the body, especially estrogen metabolism. These results indicate that the some essential metabolic pathways are sensitive to the activities of gut microorganism and directly or indirectly affected by the state of intestinal bacteria, thus gut microflora plays an important role in whole body physiology.

Salvianolic acid B functioned as a competitive inhibitor of matrix metalloproteinase-9 and efficiently prevented cardiac remodeling

Background

Infarct-induced left ventricular (LV) remodeling is a deleterious consequence after acute myocardial infarction (MI) which may further advance to congestive heart failure. Therefore, new therapeutic strategies to attenuate the effects of LV remodeling are urgently needed. Salvianolic acid B (SalB) from Salviae mitiorrhizae, which has been widely used in China for the treatment of cardiovascular diseases, is a potential candidate for therapeutic intervention of LV remodeling targeting matrix metalloproteinase-9 (MMP-9).

Results

Molecular modeling and LIGPLOT analysis revealed in silico docking of SalB at the catalytic site of MMP-9. Following this lead, we expressed truncated MMP-9 which contains only the catalytic domain, and used this active protein for in-gel gelatin zymography, enzymatic analysis, and SalB binding by Biacore. Data generated from these assays indicated that SalB functioned as a competitive inhibitor of MMP-9. In our rat model for cardiac remodeling, western blot, echocardiography, hemodynamic measurement and histopathological detection were used to detect the effects and mechanism of SalB on cardio-protection. Our results showed that in MI rat, SalB selectively inhibited MMP-9 activities without affecting MMP-9 expression while no effect of SalB was seen on MMP-2. Moreover, SalB treatment in MI rat could efficiently increase left ventricle wall thickness, improve heart contractility, and decrease heart fibrosis.

Conclusions

As a competitive inhibitor of MMP-9, SalB presents significant effects on preventing LV structural damage and preserving cardiac function. Further studies to develop SalB and its analogues for their potential for cardioprotection in clinic are warranted.

Interaction of salvianolic acids and notoginsengnosides in inhibition of ADP-induced platelet aggregation

Salvia miltiorrhiza and Panax notoginseng were both considered to be beneficial to cardiovascular diseases in traditional Chinese medicine and often used in combination. To examine the possible interaction between them, the effects of the active fractions of these two herbs, salvianolic acids (SA) and notoginsengnosides (NG), on platelet aggregation were checked respectively or in combination in vitro and in vivo. Both the platelet aggregation of platelet rich plasma (PRP) and washed platelet after ADP induction were checked. In vitro study showed that both SA and NG had an inhibitory effect on platelet aggregation. However, there is no synergistic effect of the combination of SA and NG in vitro. In vivo study showed that i.g. 550 mg/kg/day SA or NG for 5 days could significantly inhibit ADP-induced platelet aggregation of PRP. Moreover, combination of SA and NG at a ratio of 5:1 had a synergistic effect on platelet aggregation of PRP. The mechanism for the synergism of SA and NG in vivo was not clear. High performance liquid chromatography analysis of the plasma of rats received SA, NG or combination of SA and NG showed that co-administration of NG caused change in the plasma distribution profile of SA. The influence of combination on the absorption and/or metabolism of SA may be one of the reasons for the synergism of SA and NG in vivo.

Plasma and urinary tanshinol from Salvia miltiorrhiza (Danshen) can be used as pharmacokinetic markers for cardiotonic pills, a cardiovascular herbal medicine

Cardiotonic pills are a type of cardiovascular herbal medicine. To identify suitable pharmacokinetic (PK) marker(s) for indicating systemic exposure to cardiotonic pills, we examined the in vivo PK properties of putatively active phenolic acids from the component herb Danshen (Radix Salviae miltiorrhizae). We also performed in vitro and in silico assessments of permeability and solubility. Several phenolic acids were investigated, including tanshinol (TSL); protocatechuic aldehyde (PCA); salvianolic acids A, B, and D; rosmarinic acid; and lithospermic acid. Plasma TSL exhibited the appropriate PK properties in dogs, including dose-dependent systemic exposure in area under concentration-time curve (AUC) and a 0.5-h elimination half-life. In rats, more than 60% of i.v. TSL was excreted intact into the urine. In humans, we found a significant correlation between the urinary recovery of TSL and its plasma AUC. The absorption rate and bioavailability of TSL were not significantly different whether cardiotonic pills were given p.o. or sublingually. The gender specificity in plasma AUC disappeared after body-weight normalization, but the renal excretion of TSL was significantly greater in women than in men. PCA was predicted to be highly permeable according to in vitro and in silico studies; however, extensive presystemic hepatic elimination and degradation in the erythrocytes led to extremely low plasma levels and poor dose proportionality. Integrated in vivo, in vitro, and in silico studies on the other phenolic acids showed poor gut permeability and nearly undetectable levels in plasma and urine. In conclusion, plasma and urinary TSL are promising PK markers for cardiotonic pills at the tested dose levels.