NMR-based metabonomic study on the subacute toxicity of aristolochic acid in rats

Development of an immunochromatographic test strip for the rapid detection of aristolochic acid A in herbal medicinal materials

INTRODUCTION

Plants containing aristolochic acid and its derivatives are nephrotoxic, mutagenic, and carcinogenic to humans; chronic diet poisoning caused by the aristolochic acid is the cause of endemic (Balkan) nephropathy and related cancers.

OBJECTIVE

To develop a colloidal gold immunochromatographic test strip (ICS) based on the competitive format for the rapid detection of aristolochic acid A (AA-A) in herbal medicinal materials.

MATERIALS AND METHODS

For the ICS based on gold nanoparticles (AuNPs), the antigen [AA-A-bovine serum albumin (BSA)], and goat anti-mouse IgG were drawn on the nitrocellulose membrane as the test line (T line) and the control line (C line), respectively. Monoclonal antibody (MAb)-AuNP conjugates were sprayed onto the conjugate pad. The sensitivity of the ICS was 6 ng/mL, and the test was completed in 10 min. The analysis of AA-A in traditional Chinese medicine samples showed that the ICS results were in good agreement with those obtained by high-performance liquid chromatography methods.

CONCLUSION

These results demonstrated that the ICS test could be used as a reliable, rapid, cost-effective, and convenient qualitative tool for on-site screening techniques to detect AA-A in herbal medicinal materials without any special instrumentation.

NMR as a "Gold Standard" Method in Drug Design and Discovery

Studying disease models at the molecular level is vital for drug development in order to improve treatment and prevent a wide range of human pathologies. Microbial infections are still a major challenge because pathogens rapidly and continually evolve developing drug resistance. Cancer cells also change genetically, and current therapeutic techniques may be (or may become) ineffective in many cases. The pathology of many neurological diseases remains an enigma, and the exact etiology and underlying mechanisms are still largely unknown. Viral infections spread and develop much more quickly than does the corresponding research needed to prevent and combat these infections; the present and most relevant outbreak of SARS-CoV-2, which originated in Wuhan, China, illustrates the critical and immediate need to improve drug design and development techniques. Modern day drug discovery is a time-consuming, expensive process. Each new drug takes in excess of 10 years to develop and costs on average more than a billion US dollars. This demonstrates the need of a complete redesign or novel strategies. Nuclear Magnetic Resonance (NMR) has played a critical role in drug discovery ever since its introduction several decades ago. In just three decades, NMR has become a "gold standard" platform technology in medical and pharmacology studies. In this review, we present the major applications of NMR spectroscopy in medical drug discovery and development. The basic concepts, theories, and applications of the most commonly used NMR techniques are presented. We also summarize the advantages and limitations of the primary NMR methods in drug development.

Study on the mechanism of cantharidin-induced hepatotoxicity in rat using serum and liver metabolomics combined with conventional pathology methods

Cantharidin (CTD), a compound secreted from Mylabris species, exhibits strong antitumor properties; however, hepatotoxicity restricts its clinical application. The mechanism by which CTD induces toxicity remains unclear. In the present study, the hepatotoxicity of CTD in the rat was investigated using a metabolomic approach combined with conventional pathology methods. A total of 30 rats were intragastrically treated with two doses of CTD (0.75 and 1.5 mg/kg) for 15 days to evaluate hepatotoxicity. Serum and liver samples were collected for biochemical dynamics analyses, histopathological examination and metabolomic analysis. It was found that liver index and serum biochemical indices were significantly increased. Furthermore, the pathology results showed that hepatocytes and subcellular organelles were damaged. Metabolomics analysis found 4 biomarkers in serum and 15 in the liver that were associated with CTD-induced hepatotoxicity. In addition, these were responsible for CTD hepatotoxicity by glycerophospholipid metabolism, sphingolipid metabolism, and steroid hormone biosynthesis. In conclusion, conventional pathology and metabolomics for exploring hepatotoxicity can provide useful information about the safety and potential risks of CTD.

The Use of Omic Technologies Applied to Traditional Chinese Medicine Research

Natural products represent one of the most important reservoirs of structural and chemical diversity for the generation of leads in the drug development process. A growing number of researchers have shown interest in the development of drugs based on Chinese herbs. In this review, the use and potential of omic technologies as powerful tools in the modernization of traditional Chinese medicine are discussed. The analytical combination from each omic approach is crucial for understanding the working mechanisms of cells, tissues, organs, and organisms as well as the mechanisms of disease. Gradually, omic approaches have been introduced in every stage of the drug development process to generate high-quality Chinese medicine-based drugs. Finally, the future picture of the use of omic technologies is a promising tool and arena for further improvement in the modernization of traditional Chinese medicine.

The interactive effects of mercury and selenium on metabolic profiles, gene expression and antioxidant enzymes in halophyte Suaeda salsa

Suaeda salsa is the pioneer halophyte in the Yellow River Delta and was consumed as a popular vegetable. Mercury has become a highly risky contaminant in the sediment of intertidal zones of the Yellow River Delta. In this work, we investigated the interactive effects of mercury and selenium in S. salsa on the basis of metabolic profiling, antioxidant enzyme activities and gene expression quantification. Our results showed that mercury exposure (20 μg L(-1)) inhibited plant growth of S. salsa and induced significant metabolic responses and altered expression levels of INPS, CMO, and MDH in S. salsa samples, together with the increased activities of antioxidant enzymes including SOD and POD. Overall, these results indicated osmotic and oxidative stresses, disturbed protein degradation and energy metabolism change in S. salsa after mercury exposures. Additionally, the addition of selenium could induce both antagonistic and synergistic effects including alleviating protein degradation and aggravating osmotic stress caused by mercury.

Toxicological effects of benzo(a)pyrene, DDT and their mixture on the green mussel Perna viridis revealed by proteomic and metabolomic approaches

Benzo(a)pyrene (BaP) and dichlorodiphenyltrichloroethane (DDT) are persistent organic pollutants and environmental estrogens (EEs) with known toxicity towards the green mussel, Perna viridis. In this study, the toxic effects of BaP (10 µg/L) and DDT (10 µg/L) and their mixture were assessed in green mussel gills with proteomic and metabolomic approaches. Metabolic responses indicated that BaP mainly caused disturbance in osmotic regulation by significantly decrease in branched chain amino acids, dimethylamine and dimethylglycine in gills of male green mussels after exposure for 7 days. DDT mainly caused disturbance in osmotic regulation and energy metabolism by differential alteration of betaine, dimethylamine, dimethylglycine, amino acids, and succinate in gills of male green mussels. However, the mixture of BaP and DDT didn't show obvious metabolite changes. Proteomic analysis showed different protein expression profiles between different treatment groups, which demonstrated that BaP, DDT and their mixture may have different modes of action. Proteomic responses revealed that BaP induced cell apoptosis, disturbance in protein digestion and energy metabolism in gills of green mussels, whereas DDT exposure altered proteins that were associated with oxidative stress, cytoskeleton and cell structure, protein digestion and energy metabolism. However, the mixture of BaP and DDT affected proteins related to the oxidative stress, cytoskeleton and cell structure, protein biosynthesis and modification, energy metabolism, growth and apoptosis.

Comparative investigations on the biological effects of As (III) and As (V) in clam Ruditapes philippinarum using multiple biomarkers

Inorganic arsenic is a known pollutant with two chemical forms, arsenite (As (III)) and arsenate (As (V)), in marine environment. Clam Ruditapes philippinarum is an important fishery species along the Bohai coast. In this study, the biological effects induced by the two arsenic chemical forms (arsenite and arsenate) were compared using multiple biochemical indices in the digestive glands of clam R. philippinarum. The production of reactive oxygen species, antioxidant enzyme activities and metabolic responses exhibited that both As (III) and As (V) induced immune, oxidative and osmotic stresses in clam digestive glands. The differential metabolic biomarkers, histidine and taurine, indicated the differential responsive mechanisms in osmotic regulation in clam digestive glands. In addition, both arsenic treatments enhanced the anaerobiosis metabolism in clam digestive glands. Overall, this work illustrated that arsenite and arsenate induced similar biological effects in clams, which might be accounted for the biological transformation of arsenate to arsenite in clams.

A metabolomic study on the responses of daphnia magna exposed to silver nitrate and coated silver nanoparticles

We examined the short-term toxicity of AgNPs and AgNO3 to Daphnia magna at sublethal levels using (1)H NMR-based metabolomics. Two sizes of polyvinylpyrrolidone-coated AgNPs (10 and 40nm) were synthesized and characterized and their Ag(+) release was studied using centrifugal ultrafiltration and inductively coupled plasma mass spectrometry. Multivariate statistical analysis of the (1)H NMR spectra showed significant changes in the D. magna metabolic profiles following 48h exposure to both AgNP particle sizes and Ag(+) exposure. Most of the metabolic biomarkers for AgNP exposure, including 3-hydroxybutyrate, arginine, lysine and phosphocholine, were identical to those of the Ag(+)-exposed groups, suggesting that the dominant effects of both AgNPs were due to released Ag(+). The observed metabolic changes implied that the released Ag(+) induced disturbance in energy metabolism and oxidative stress, a proposed mechanism of AgNP toxicity. Elevated levels of lactate in all AgNP-treated but not in Ag(+)-treated groups provided evidence for Ag-NP enhanced anaerobic metabolism. These findings show that (1)H NMR-based metabolomics provides a sensitive measure of D. magna response to AgNPs and that further targeted assays are needed to elucidate mechanisms of action of nanoparticle-induced toxicity.

Multiple biomarkers of biological effects induced by cadmium in clam Ruditapes philippinarum

Cadmium (Cd) is a known heavy metal pollutant in the Bohai Sea. Manila clam Ruditapes philippinarum is an important fishery species along the Bohai coast. In this study, the biological effects induced by two concentrations (20 and 200 μg/L) of Cd were characterized using multiple biochemical indices in the digestive glands of clam R. philippinarum. The total hemocyte counts, reactive oxygen species productions and antioxidant enzyme activities exhibited that Cd induced dose-dependent immune and oxidative stresses in clam digestive glands. Metabolic responses indicated that both Cd exposures caused immune stress marked by the elevated branched chain amino acids (valine, leucine and isoleucine), together with the disturbance in energy metabolism. The differential metabolic biomarkers related to osmotic stress, including homarine, betaine, tyrosine and phenylalanine, suggested the differential responsive mechanisms in clam digestive glands induced by Cd exposures. In addition, both Cd treatments enhanced the anaerobiosis metabolism in clam digestive glands via differential metabolic pathways.

Toxicological evaluation of two pedigrees of clam Ruditapes philippinarum as bioindicators of heavy metal contaminants using metabolomics

Heavy metal pollution has been of great concern in the Bohai marine environment. Manila clam Ruditapes philippinarum has been used as a bioindicator in marine toxicology. In this study, NMR-based metabolomics was used to ascertain whether there were significant biological differences between two dominant pedigrees (White and Zebra) of clam and evaluate the suitability of two pedigrees for marine environmental toxicology, together with antioxidant enzymatic analysis. Our results indicated that there were significant biological differences between White and Zebra clams based on the metabolic profiles and antioxidant enzyme activities. In details, the metabolic profiles showed higher levels of amino acids and succinate in Zebra clam digestive glands and higher levels of ATP in White clam digestive glands, respectively. The superoxide dismutase activities in control White and Zebra clam samples were significantly different. Additionally, White clam was more sensitive to Cd based on the significant accumulation of Cd, antioxidant enzymatic alterations and sensitive metabolic changes. Overall, we concluded that White clam could be a preferable bioindicator for marine environmental toxicology.

Metabolomics in nephrotoxicity

Nephrotoxicity or renal toxicity can be a result of hemodynamic changes, direct injury to cells and tissue, inflammatory tissue injury, and/or obstruction of renal excretion. Nephrotoxicity is frequently induced by a wide spectrum of therapeutic drugs and environ mental pollutants. Knowledge of the complex molecular and pathophysiologic mechanisms leading to nephrotoxicity remains limited, in part, by research that historically focused on single or relatively few risk markers. As such, current kidney injury biomarkers are inadequate in terms of sensitivity and specificity. In contrast, metabolomics enables screening of a vast array of metabolites simultaneously using NMR and MS to assess their role in nephrotoxicity development and progression. A more comprehensive understanding of these biochemical pathways would also provide valuable insight to disease mechanisms critical for drug development and treatment.

Metabolomic analysis of complex chinese remedies: examples of induced nephrotoxicity in the mouse from a series of remedies containing aristolochic Acid

Aristolochic acid nephropathy is caused by aristolochic acid (AA) and AA-containing herbs. In traditional Chinese medicine, a principle called “Jun-Chen-Zou-Shi” may be utilized to construct a remedial herbal formula that attempts to mitigate the toxicity of the main ingredient. This study used Bu-Fei-A-Jiao-Tang (BFAJT) to test if the compound remedy based on a principle of “Jun-Chen-Zou-Shi” can decrease the toxicity of AA-containing herbs. We compared the three toxicities of AA standard, Madouling (an Aristolochia herb), and a herbal formula BFAJT. AA standard was given for BALB/c mice at a dose of 5 mg/kg bw/day or 7.5 mg/kg bw/day for 10 days. Madouling and BFAJT were given at an equivalence of AA 0.5 mg/kg bw/day for 21 days. Nephrotoxicity was evaluated by metabolomics and histopathology. The urinary metabolomics profiles were characterized by ¹H NMR spectroscopy. The spectral data was analyzed with partial least squares discriminant analysis, and the significant differential metabolites between groups were identified. The result showed different degrees of acute renal tubular injuries, and metabolomics analysis found that the kidney injuries were focused in proximal renal tubules. Both metabolomics and pathological studies revealed that AA standard, Madouling, and BFAJT were all nephrotoxicants. The compositions of the compound remedy did not diminish the nephrotoxicity caused by AA.

Zinc oxide nanoparticles cause nephrotoxicity and kidney metabolism alterations in rats

Although zinc oxide nanoparticles (ZnO NPs) have been widely used, their potential hazards on mammalian and human remain largely unknown. In this study, the biochemical compositions of urine and kidney from the rats treated with ZnO NPs (100, 300 and 1000 mg/kg, respectively) were investigated using (1)H nuclear magnetic resonance (NMR) technique with the pattern recognition of partial least squares-discriminant analysis. Hematology, clinical biochemistry and kidney histopathological examinations were also performed. Metabolic profiles from rats treated with ZnO NP(S) exhibited increases in the levels of taurine, lactate, acetate, creatine, phosphocholine, trimethylamine-N-oxide, α-glucose, and 3-D-hydroxybutyrate, as well as decreases in lipid, succinate, citrate, α-ketoglutarate, hippurate and 4-hydroxyphenylacetic acid in urine after ZnO NPs treatment for 14 days. A similar alteration pattern was also identified in kidney. Urine choline and phosphocholine increased significantly shortly after ZnO NPs treatment, moreover, some amino acids and glucose also increased during the experimental period. However, succinate, citrate and α-ketoglutarate in urine exhibited a different alteration trend, which showed increases on the first day after ZnO NPs treatment, but decreases gradually until the termination of the study. A similar alteration pattern of urinary (1)H NMR spectra was also detected in kidney. Moreover, ZnO NPs (1000 mg/kg) resulted in significant increases in serum creatine and blood urea nitrogen, decreases in hemoglobin, haematocrit and mean corpuscular hemoglobin concentration, and overt tubular epithelial cell necrosis. These findings show that ZnO NPs can disturb the energy metabolism and cause mitochondria and cell membrane impairment in rat kidney, which may contribute to ZnO NPs-induced nephrotoxicity.

Review of current and "omics" methods for assessing the toxicity (genotoxicity, teratogenicity and nephrotoxicity) of herbal medicines and mushrooms

ETHNOPHARMACOLOGICAL RELEVANCE

The increasing use of traditional herbal medicines around the world requires more scientific evidence for their putative harmlessness. To this end, a plethora of methods exist, more or less satisfying. In this post-genome era, recent reviews are however scarce, not only on the use of new "omics" methods (transcriptomics, proteomics, metabonomics) for genotoxicity, teratogenicity, and nephrotoxicity assessment, but also on conventional ones.

METHODS

The present work aims (i) to review conventional methods used to assess genotoxicity, teratogenicity and nephrotoxicity of medicinal plants and mushrooms; (ii) to report recent progress in the use of "omics" technologies in this field; (iii) to underline advantages and limitations of promising methods; and lastly (iv) to suggest ways whereby the genotoxicity, teratogenicity, and nephrotoxicity assessment of traditional herbal medicines could be more predictive.

RESULTS

Literature and safety reports show that structural alerts, in silico and classical in vitro and in vivo predictive methods are often used. The current trend to develop "omics" technologies to assess genotoxicity, teratogenicity and nephrotoxicity is promising but most often relies on methods that are still not standardized and validated.

CONCLUSION

Hence, it is critical that toxicologists in industry, regulatory agencies and academic institutions develop a consensus, based on rigorous methods, about the reliability and interpretation of endpoints. It will also be important to regulate the integration of conventional methods for toxicity assessments with new "omics" technologies.

An NMR-based metabonomic investigation of the subacute effects of melamine in rats

The subacute toxic effects of 28 days of exposure to three dosages (250, 500, 1000 mg/kg/day) of melamine on Wistar rats were investigated using nuclear magnetic resonance spectra, histopathological examination, and biochemical analysis. Rats treated with melamine developed adverse health effects compared to the controls, including decrease in body weight and kidney damage. Blood biochemical analysis showed that the blood urea nitrogen and creatinine increased distinctly compared to the control group. Urinary metabonomic analysis indicated that melamine caused an increase in succinate and citrate. Serum metabonomic analysis showed that the lowest dose led to an increase in dimethylglycine, N-acetylglycoprotein (NAC), accompanied by a decrease in taurine and glucose. Rats treated with the highest dose developed high levels of serum choline and 3-hydroxybutyrate (3-HB) together with low lactate levels. Metabonomic analysis of liver tissue indicated that melamine caused an increase in NAC, choline, and creatine, accompanied by a decrease in lactate, trimethylamine-N-oxide, glutamate, and glucose. All three dosages resulted in an increase in glutamate, lactate, choline, glucose, and animo acids and a decrease in 3-HB and pyruvate in aqueous kidney extract. These results indicate that melamine not only caused renal disfunction but also disturbed the liver's glucose, protein, and nitrogen metabolism.

Unsupervised principal component analysis of NMR metabolic profiles for the assessment of substantial equivalence of transgenic grapes (Vitis vinifera)

Substantial equivalence is a key concept in the evaluation of unintended and potentially harmful metabolic impact consequent to a genetic modification of food. The application of unsupervised multivariate data analysis to the metabolic profiles is expected to improve the effectiveness of such evaluation. The present study uses NMR spectra of hydroalcoholic extracts, as holistic representations of the metabolic profiles of grapes, to evaluate the effect of the insertion of one or three copies of the DefH9-iaaM construct in plants of Silcora and Thompson Seedless cultivars. The comparison of the metabolic profiles of transgenic derivatives with respect to their corresponding natural lines pointed out that the overall metabolic changes occur in the same direction, independent of the host genotype, although the two cultivars are modified to different extents. A higher number of copies not only produces a larger effect but also modifies the whole pattern of perturbed metabolites.

Metabolomics for bioactivity assessment of natural products

Natural products historically have been a rich source of lead molecules in drug discovery, based on their capability to create unique and diverse chemical structures. However, it is also true that the vast number of metabolites typically present in natural products and their huge dynamic range results in the loss of many possibly bioactive natural compounds, becoming an inextricable obstacle for drug development. Recently, new strategies which favour a holistic approach as opposed to the traditional reductionist methods used previously, have been introduced with the purpose of overcoming the bottlenecks in natural product research. This approach is based on the application of new technologies, including metabolomics, for example. Metabolomics allows a systematic study of a complex mixture such as a phytochemical preparation, which can be linked to observations obtained through biological testing systems without the need for isolating active principles. This may put drug discovery from natural products back in the limelight again. In this review paper, the description of some examples of successful metabolomics applications in several important fields related to drug discovery from natural sources aims at raising the potential of metabolomics in reducing the gap between natural products (NP) and modern drug discovery demand.

Comparative Nephrotoxicity of Aristolochic Acid and Tetrandrine In Vitro and In Vivo

Aristolochic acid (AA) and tetrandrine (TET) are the major bioactive components in Chinese herbs used for weight loss. The nephropathy caused by the 2 Chinese herbs has not been simultaneously investigated. The aim of this study was to examine the potential nephrotoxicity of AA and TET using Madin-Darby canine kidney (MDCK) cells and mice. The results showed that TET was more potent than AA in inhibiting MDCK cell growth via inducing apoptosis, as determined by annexin-V staining, 4’, 6’-diamino-2-phenylindole (DAPI) staining, DNA fragmentation, and caspase 3 activity. Mice treated with AA (10 mg/kg) by intraperitoneal administration for 3 months showed nephrotoxicity, elevated blood urea nitrogen, and increased renal tubular injuries. In contrast, mice treated with 50 mg/kg of TET in the same time period had moderate hydropic degeneration of the distal tubules in the kidneys. These results suggest that TET is more cytotoxic than AA in MDCK cells but shows less nephrotoxic than AA in mice.

Liquid chromatography/mass spectrometry for investigating the biochemical effects induced by aristolochic acid in rats: the plasma metabolome

In this study, high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry in conjunction with chemometric methods including principal components analysis was used to investigate metabolic profiling in plasma samples from rats dosed with aristolochic acid (AA). Differentiating metabolites were identified by high-resolution mass spectrometry and tandem mass spectrometry analyses, database searching and comparison with the analytical results of authentic standards. Several metabolites in plasma including a glucuronide conjugate, bile acids, lysophosphatidylcholines and fatty acids were detected in rats exposed to AA. To improve visualization, a z-score plot and a cluster heat map were generated for the concentration fluctuations of the metabolites in different dosage groups. The results obtained from this study indicated that class-specific metabolomic patterns were obviously differentiated for each metabolite in the different dosage groups of AA.

Assessment of herbal medicinal products: challenges, and opportunities to increase the knowledge base for safety assessment

Although herbal medicinal products (HMP) have been perceived by the public as relatively low risk, there has been more recognition of the potential risks associated with this type of product as the use of HMPs increases. Potential harm can occur via inherent toxicity of herbs, as well as from contamination, adulteration, plant misidentification, and interactions with other herbal products or pharmaceutical drugs. Regulatory safety assessment for HMPs relies on both the assessment of cases of adverse reactions and the review of published toxicity information. However, the conduct of such an integrated investigation has many challenges in terms of the quantity and quality of information. Adverse reactions are under-reported, product quality may be less than ideal, herbs have a complex composition and there is lack of information on the toxicity of medicinal herbs or their constituents. Nevertheless, opportunities exist to capitalise on newer information to increase the current body of scientific evidence. Novel sources of information are reviewed, such as the use of poison control data to augment adverse reaction information from national pharmacovigilance databases, and the use of more recent toxicological assessment techniques such as predictive toxicology and omics. The integration of all available information can reduce the uncertainty in decision making with respect to herbal medicinal products. The example of Aristolochia and aristolochic acids is used to highlight the challenges related to safety assessment, and the opportunities that exist to more accurately elucidate the toxicity of herbal medicines.

Application of metabonomic analytical techniques in the modernization and toxicology research of traditional Chinese medicine

In the recent years, a wide range of metabonomic analytical techniques are widely used in the modern research of traditional Chinese medicine (TCM). At the same time, the international community has attached increasing importance to TCM toxicity problems. Thus, many studies have been implemented to investigate the toxicity mechanisms of TCM. Among these studies, many metabonomic-based methods have been implemented to facilitate TCM toxicity investigation. At present, the most prevailing methods for TCM toxicity research are mainly single analysis techniques using only one analytical means. These techniques include nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS), etc.; with these techniques, some favourable outcomes have been gained in the toxic reaction studies of TCM, such as the action target organs assay, the establishment of action pattern, the elucidation of action mechanism and the exploration of action material foundation. However, every analytical technique has its advantages and drawbacks, no existing analytical technique can be versatile. Multi-analysed techniques can partially overcome the shortcomings of single-analysed techniques. Combination of GC-MS and LC-MS metabolic profiling approaches has unravelled the pathological outcomes of aristolochic acid-induced nephrotoxicity, which can not be achieved by single-analysed techniques. It is believed that with the further development of metabonomic analytical techniques, especially multi-analysed techniques, metabonomics will greatly promote TCM toxicity research and be beneficial to the modernization of TCM in terms of extending the application of modern means in the TCM safety assessment, assisting the formulation of TCM safety norms and establishing the international standards indicators.

Metabolic profiling studies on the toxicological effects of realgar in rats by (1)H NMR spectroscopy

The toxicological effects of realgar after intragastrical administration (1 g/kg body weight) were investigated over a 21 day period in male Wistar rats using metabonomic analysis of (1)H NMR spectra of urine, serum and liver tissue aqueous extracts. Liver and kidney histopathology examination and serum clinical chemistry analyses were also performed. (1)H NMR spectra and pattern recognition analyses from realgar treated animals showed increased excretion of urinary Kreb's cycle intermediates, increased levels of ketone bodies in urine and serum, and decreased levels of hepatic glucose and glycogen, as well as hypoglycemia and hyperlipoidemia, suggesting the perturbation of energy metabolism. Elevated levels of choline containing metabolites and betaine in serum and liver tissue aqueous extracts and increased serum creatine indicated altered transmethylation. Decreased urinary levels of trimethylamine-N-oxide, phenylacetylglycine and hippurate suggested the effects on the gut microflora environment by realgar. Signs of impairment of amino acid metabolism were supported by increased hepatic glutamate levels, increased methionine and decreased alanine levels in serum, and hypertaurinuria. The observed increase in glutathione in liver tissue aqueous extracts could be a biomarker of realgar induced oxidative injury. Serum clinical chemistry analyses showed increased levels of lactate dehydrogenase, aspartate aminotransferase, and alkaline phosphatase as well as increased levels of blood urea nitrogen and creatinine, indicating slight liver and kidney injury. The time-dependent biochemical variations induced by realgar were achieved using pattern recognition methods. This work illustrated the high reliability of NMR-based metabonomic approach on the study of the biochemical effects induced by traditional Chinese medicine.

Liquid chromatography/mass spectrometry for metabonomics investigation of the biochemical effects induced by aristolochic acid in rats: the use of information-dependent acquisition for biomarker identification

The toxic effects of oral administrations of nephrotoxic and carcinogenic aristolochic acid (AA) to male Sprague-Dawley rats were investigated by using high-performance liquid chromatography coupled with a quadrupole time-of-flight mass spectrometer. Analysis of the urine and plasma samples revealed distinct changes in the biochemical patterns in the AA-dosed rats. After peak finding and alignment, principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) were used for multivariate data analysis. Potential biomarkers were studied by high-resolution mass spectrometry (MS) and tandem mass spectrometry (MS/MS) analyses. The MS/MS spectra of all endogenous metabolites satisfying the pre-defined criteria were acquired in a single information-dependent acquisition (IDA) analysis, demonstrating that IDA was an efficient approach for structural elucidation in metabonomic studies. Citric acid and a glucuronide-containing metabolite were observed as potential biomarkers in rat urine. A significant increase in plasma creatinine concentration was also observed in the AA-dosed rats, which indicated that AA induced an adverse effect on the renal clearance function.

New molecular and field evidences for the implication of mycotoxins but not aristolochic acid in human nephropathy and urinary tract tumor

To find out whether ochratoxin A (OTA), citrinin (CIT), aristolochic acids (AA) are etiologic agents of Balkan endemic nephropathy (BEN) or Chinese herbal nephrotoxicity, and associated urinary tract tumor (UTT), we have compared (i) in human kidney cell culture, the DNA adduct formation and persistence of OTA/CIT and AA adducts (ii) analyzed DNA adduct in several tumors from human kidney suspected to be exposed to either OTA and CIT, or AAs (iii) analyzed OTA, CIT, and AA in food. In kidney cell cultures, formation of specific OTA-DNA adduct and AA-DNA adduct were detected in the same range (around 10 adducts/10(9) nucleotides) and were time- and dose-dependent. After 2 days all disappeared. DNA adduct related to OTA and CIT are found in human kidney tissues from Balkans, France, and Belgium whereas no DNA adducts related to AA could be found in any tumors of BEN patients from Croatia, Bulgaria, or Serbia. No DNA adduct was found in kidney biopsy or necropsy of the French women suspected to be exposed to AA. OTA and CIT are more frequently found in rural area. AA was never detected. All these plead for implication of mycotoxins, especially OTA, in BEN and UTT.

Transforming Growth Factor and Nuclear Factor Kappa B Mediated Prophylactic Cardioprotection by Total Flavonoids of Fructus Chorspondiatis in Myocardial Ischemia

BACKGROUND

Chorspomias axillaries Batt et Hill, a well-known Chinese herb, has been used in clinical treatment of angina pectoris for hundreds of years, but its effective components and intrinsic cardioprotective mechanism are still beyond us.

OBJECTIVES AND METHODS

In this study, we extracted Total Flavonoids of Fructus Chorspondiatis (TFFC), a potential effective component from Chorspomias axillaries Batt et Hill to investigate its effect on myocardial ischemia induced by isoproteronol in rat and elucidated its probable mechanism.

RESULTS

The results showed that prophylactically ;;intragastrical administration of TFFC at the dose of 200 mg/kg body weight effectively suppressed the variation of J points in electrocardiogram (0.211 +/- 0.059( )mV versus 0.277 +/- 0.046( )mV, p < 0.05) and inhibited the upregulated serum level of creatine kinase (754 +/- 114( )U/l versus 1,112 +/- 239( )U/l, p < 0.05), creatine kinase -MB (700 +/- 95( )U/l versus 1,012 +/- 252( )U/l, p < 0.05) and lactate dehydrogenase (1,174 +/- 200( )U/l versus 2,025 +/- 975( )U/l, p < 0.05) in myocardial ischemia, revealing its cardioprotective effect. It increased a potent tissue protective polypeptide, transforming growth factor beta(1) (TGF-beta(1)) level as well as its receptors TbetaRI and TbetaRII(p < 0.05) and significantly inhibited the expression of a redox-sensitive transcription factor, nuclear factor kappa B (NF-kappaB).

CONCLUSIONS

These data demonstrated that TFFC at the dose of 200 mg/kg body weight exerts prophylactically cardioprotective effect during ischemia injury. Part of its cardioprotective mechanism may relate to induction of TGF-beta(1) to competitively inhibit NF-kappaB signaling pathway. Prophylactically exogenous administration with the component may serve as a novel therapeutic strategy for ischemic cardiovascular diseases.

Detection of urinary drug metabolite (xenometabolome) signatures in molecular epidemiology studies via statistical total correlation (NMR) spectroscopy

Western populations use prescription and nonprescription drugs extensively, but large-scale population usage is rarely assessed objectively in epidemiological studies. Here we apply statistical methods to characterize structural pathway connectivities of metabolites of commonly used drugs detected routinely in 1H NMR spectra of urine in a human population study. 1H NMR spectra were measured for two groups of urine samples obtained from U.S. participants in a known population study. The novel application of a statistical total correlation spectroscopy (STOCSY) approach enabled rapid identification of the major and certain minor drug metabolites in common use in the population, in particular, from acetaminophen and ibuprofen metabolites. This work shows that statistical connectivities between drug metabolites can be established in routine "high-throughput" NMR screening of human samples from participants who have randomly self-administered drugs. This approach should be of value in considering interpopulation patterns of drug metabolism in epidemiological and pharmacogenetic studies.