Metabolomic profiling of rat urine after oral administration of the prescription antipyretic Hao Jia Xu Re Qing Granules by UPLC/Q-TOF-MS.

Hao Jia Xu Re Qing Granules (HJ), is an effective clinically used antipyretic based on traditional Chinese medicine. Although its antipyretic therapeutic effectiveness is obvious, its therapeutic mechanism has not been comprehensively explored yet. In this research, we first identified potential biomarkers which may be relevant for the antipyretic effect of HJ based on urine metabolomics using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). A rat model of fever was established using the yeast-induced febrile response. Total-ion-current metabolic profiles of different groups were acquired and the data were processed by multivariate statistical analysis-partial least-squares discriminant analysis. As envisioned, the results revealed changes of urine metabolites related to the antipyretic effect. Fourteen potential biomarkers were selected from the urine samples based on the results of Student's t-test, "shrinkage t", variable importance in projection and partial least-squares discriminant analysis. N-Acetylleucine, kynurenic acid, indole-3-ethanol, nicotinuric acid, pantothenic acid and tryptophan were the most significant biomarkers found in the urine samples, and may be crucially related to the antipyretic effect of HJ. Consequently, we propose the hypothesis that the significant antipyretic effect the HJ may be related to the inhibition of tryptophan metabolism. This research thus provides strong theoretical support and further direction to explain the antipyretic mechanism of HJ, laying the foundation for future studies.

An integrated strategy by using target tissue metabolomics biomarkers as pharmacodynamic surrogate indices to screen antipyretic components of Qingkaikling injection.

Traditional Chinese medicine (TCM) treatment can be valuable therapeutic strategies. However, the active components and action mechanisms that account for its therapeutic effects remain elusive. Based on the hypothesis that the components of a formula which exert effect would be measurable in target tissue, a target tissue metabolomics-based strategy was proposed for screening of antipyretic components in Qingkaikling injection (QKLI). First, we detected the components of QKLI which could reach its target tissue (hypothalamus) by determining the hypothalamus microdialysate and discovered that only baicalin and geniposide could be detected. Then, by conducting hypothalamus metabolomics studies, 14 metabolites were screened as the potential biomarkers that related to the antipyretic mechanisms of QKLI and were used as its pharmacodynamic surrogate indices. Subsequently, the dynamic concentration of baicalin and geniposide in hypothalamus microdialysates and biomarkers in hypothalamus were measured and correlated with each other. The results indicated that only baicalin shown a good correlation with these biomarkers. Finally, a network pharmacology approach was established to validate the antipyretic activity of baicalin and the results elucidated its antipyretic mechanisms as well. The integrated strategy proposed here provided a powerful means for identifying active components and mechanisms contributing to pharmacological effects of TCM.

Pharmacokinetic-Pharmacodynamic Modeling to Study the Antipyretic Effect of Qingkailing Injection on Pyrexia Model Rats.

Qingkailing injection (QKLI) is a modern Chinese medicine preparation derived from a well-known classical formulation, An-Gong-Niu-Huang Wan. Although the clinical efficacy of QKLI has been well defined, its severe adverse drug reactions (ADRs) were extensively increased. Through thorough attempts to reduce ADR rates, it was realized that the effect-based rational use plays the key role in clinical practices. Hence, the pharmacokinetic-pharmacodynamic (PK-PD) model was introduced in the present study, aiming to link the pharmacokinetic profiles with the therapeutic outcomes of QKLI, and subsequently to provide valuable guidelines for the rational use of QKLI in clinical settings. The PK properties of the six dominant ingredients in QKLI were compared between the normal treated group (NTG) and the pyrexia model group (MTG). Rectal temperatures were measured in parallel with blood sampling for NTG, MTG, model control group (MCG), and normal control group (NCG). Baicalin and geniposide exhibited appropriate PK parameters, and were selected as the PK markers to map the antipyretic effect of QKLI. Then, a PK-PD model was constructed upon the bacalin and geniposide plasma concentrations vs. the rectal temperature variation values, by a two-compartment PK model with a Sigmoid Emax PD model to explain the time delay between the drug plasma concentration of PK markers and the antipyretic effect after a single dose administration of QKLI. The findings obtained would provide fundamental information to propose a more reasonable dosage regimen and improve the level of individualized drug therapy in clinical settings.

Anti-inflammatory Activities of Erythrina variegata Bark Ethanolic Extract.

Background: The bark of Erythrina variegata Linn.(Ev) is used in Thai traditional medicine for the treatment of many diseases in Thailand and is an ingredient in the Mahanintangthong remedy (antipyretic) and Lomammapruek remedy (analgesic and anti-inflammatory). Objective: To study anti-inflammatory activities of ethanolic extract of E. variegata in vitro. Material and Method: Bark of E. variegata was extracted with 95% ethanol. In this study, Griess reagent was used to measure the anti-inflammatory activity by inhibitory effects of extract on nitric oxide production activated by lipopolysaccharide in RAW 264.7 cell lines, COX-2 and TNF-α were also tested by using ELISA techniques. Results: The ethanolic extract of E. variegata showed potent anti-inflammation properties by inhibiting prostaglandins production through enzyme COX-2 and inhibitory activity against lipopolysaccharide induced nitric oxide production in RAW 264.7 cell lines with an IC50 value of 9.27±0.72 and 47.1±0.21 µg/ml, respectively. However it was not effective against TNF-α release. Conclusion: The ethanolic extracts of E. variegata bark showed higher inhibitory effect on PGE2 as acute inflammation than inhibitory effect on Nitric oxide production and TNF-α release representing chronic inflammation. This study thus supports the use of E. variegata bark for treatment of inflammation-related diseases by Thai traditional medicine.

Glucosamine enhances paracetamol bioavailability by reducing its metabolism.

Paracetamol has an extensive first-pass metabolism that highly affects its bioavailability (BA); thus, dose may be repeated several times a day in order to have longer efficacy. However, hepatotoxicity may arise because of paracetamol metabolism. Therefore, this project aimed to increase paracetamol BA in rats by glucosamine (GlcN). At GlcN-paracetamol racemic mixture ratio of 4:1 and paracetamol dose of 10 mg/kg, paracetamol area under the curve (AUC) and maximum concentration (Cmax ) were significantly increased by 99% and 66%, respectively (p < 0.05). Furthermore, paracetamol AUC and Cmax levels were increased by 165% and 88% in rats prefed with GlcN for 2 days (p < 0.001). Moreover, GlcN significantly reduced phase Ι and phase I/ΙΙ metabolic reactions in liver homogenate by 48% and 54%, respectively. Furthermore, GlcN molecule was found to possess a good in silico binding mode into the CYP2E1 active site-forming bidentate hydrogen bonding with the Thr303 side chain. Finally, serum ALT and AST levels of rats-administered high doses of paracetamol were significantly reduced when rats were prefed with GlcN (p < 0.01). In conclusion, GlcN can increase the relative BA of paracetamol through reducing its metabolism. This phenomenon is associated with reduction in hepatocytes injury following ingestion of high doses of paracetamol.

Dipyrone metabolite 4-MAA induces hypothermia and inhibits PGE2 -dependent and -independent fever while 4-AA only blocks PGE2 -dependent fever.

BACKGROUND AND PURPOSE: The antipyretic and hypothermic prodrug dipyrone prevents PGE2 -dependent and -independent fever induced by LPS from Escherichia coli and Tityus serrulatus venom (Tsv) respectively. We aimed to identify the dipyrone metabolites responsible for the antipyretic and hypothermic effects. EXPERIMENTAL APPROACH: Male Wistar rats were treated i.p. with indomethacin (2 mg·kg(-1) ), dipyrone, 4-methylaminoantipyrine (4-MAA), 4-aminoantipyrine (4-AA) (60-360 mg·kg(-1) ), 4-formylaminoantipyrine, 4-acethylaminoantipyrine (120-360 mg·kg(-1) ) or vehicle 30 min before i.p. injection of LPS (50 µg·kg(-1) ), Tsv (150 µg·kg(-1) ) or saline. Rectal temperatures were measured by tele-thermometry and dipyrone metabolite concentrations determined in the plasma, CSF and hypothalamus by LC-MS/MS. PGE2 concentrations were determined in the CSF and hypothalamus by elisa. KEY RESULTS: In contrast to LPS, Tsv-induced fever was not followed by increased PGE2 in the CSF or hypothalamus. The antipyretic time-course of 4-MAA and 4-AA on LPS-induced fever overlapped with the period of the highest concentrations of 4-MAA and 4-AA in the hypothalamus, CSF and plasma. These metabolites reduced LPS-induced fever and the PGE2 increase in the plasma, CSF and hypothalamus. Only 4-MAA inhibited Tsv-induced fever. The higher doses of dipyrone and 4-MAA also induced hypothermia. CONCLUSIONS AND IMPLICATIONS: The presence of 4-MAA and 4-AA in the CSF and hypothalamus was associated with PGE2 synthesis inhibition and a decrease in LPS-induced fever. 4-MAA was also shown to be an antipyretic metabolite for PGE2 -independent fever induced by Tsv suggesting that it is responsible for the additional antipyretic mechanism of dipyrone. Moreover, 4-MAA is the hypothermic metabolite of dipyrone.

[Pharmacokinetic/pharmacodynamic modeling of antipyretic and reducing plasma concentration of NO effects of Rheum palmatum in rat].

Pharmacokinetic-pharmacodynamic (PK-PD) modeling was used to characterize the antipyretic and anti-inflammatory effects in rats of Rhein, a major component in rhubarb. Twenty-four healthy male Sprague-Dawley (SD) rats were randomly into four groups, of 6 each. The rats in first group were injected intravenously with lipopolysaccharide (LPS, 100 microg x kg(-1)). The second group rats were given rhubarb decoction (RD, 1.54 g x kg(-1)) by oral administration alone. The rats belonging to third group were administered orally RD 30 min after LPS injection. The rest rats were given normal saline only as control group. Orbital sinus blood sampling was collected at different time points. The Rhein and NO concentration in plasma and body temperature (BT) were measured. Relevant data of PK-PD modeling were performed with Kinetica 5. 0. 11. RD could suppress the rise in BT and plasma NO concentration. The antipyretic and anti-inflammatory responses were best described by a Sigmod-E(max) model. Delay between exposure and response was accounted for by a transit compartment model with two parallel transit compartment chains. The results showed that some parameters such as t1/2, C(max) and AUC were significantly increased in rats treated with LPS, compared to those in rats treated with normal saline. The EC50 for antipyretic effect and decrease of plasma NO concentration was respectively equal to 114.1, 90.80 microg x L(-1). The E(max) for antipyretic effect was about 111% of that for increase in BT after LPS injection. The E(max) for anti-inflammatory action was close to 8.399% of that for elevated NO level after modeling. Meanwhile, there was a difference in pharmacokinetic process of Rhein between the impact of normal saline and LPS. So, it can be concluded that the targets of regulating NO production and BT after RD administration may be at the same location. Not only do that, the antipyretic effect induced by RD maybe completely manifest through reducing the plasma concentration of NO.

The effects of lipopolysaccharide-induced endogenous hyperthermia and different antipyretic treatment modalities on rat brain.

BACKGROUND: In the present study, the effects of fever and hyperthermia, and different anti hyperthermia treatment modalities on the brain by was investigated by using experimental animal model MATERIALS AND METHODS: Endogenous hyperthermia (41 degrees C) was induced by lipopolysaccharide (LPS) injection, and the signs of probable neuronal damage were evaluated by healthy, necrotic and apoptotic cells, and heat-shock proteins (HSP 27 and HSP 70) in cerebral cortex, cerebellum and hypothalamus. The animals were treated with widely used treatment modalities for high fever in pediatric practice, namely hypothermia, dexamethasone, paracetamol and diclofenac, and their effect on the hyperthermia-induced brain changes were evaluated. RESULTS: Generalized seizure was observed in fifteen rats of which rectal temperature achieved 41 degrees C (15/36, 41%); five of them died on second day (5/15, 33%). LPS-induced endogenous hyperthermia; (i) caused significant increase of necrotic cells in cerebral cortex and cerebellum and apoptotic cells in all three regions (p < 0.05), (ii) caused significant decrease of healthy cells in cerebral cortex (p < 0.05), and (iii) no significant change of HSP 27 and 70 in all three neuronal locations (p > 0.05). For the treatment modalities applied; (i) paracetamol had an effect of increasing the healthy cell count in cerebral cortex and hypothalamus and decreasing the necrotic cell count in cerebellum and hypothalamus (p < 0.05). CONCLUSION: The neuronal tissue in different regions of brain can show various degrees of damage in response to endogenous hyperthermia and the applied medications have varying degree of protection (Tab. 3, Fig. 6, Ref. 44).

Pharmacokinetic-pharmacodynamic modeling of the inhibitory effects of naproxen on the time-courses of inflammatory pain, fever, and the ex vivo synthesis of TXB2 and PGE2 in rats.

PURPOSE: To quantify and compare the time-course and potency of the analgesic and antipyretic effects of naproxen in conjunction with the inhibition of PGE(2) and TXB(2). METHODS: Analgesia was investigated in a rat model with carrageenan-induced arthritis using a gait analysis method. Antipyretics were studied in a yeast-induced fever model using telemetrically recorded body temperature. Inhibition of TXB(2) and PGE(2) synthesis was determined ex vivo. Pharmacokinetic profiles were obtained in satellite animals. Population PKPD modeling was used to analyze the data. RESULTS: The IC(50) values (95% CI) of naproxen for analgesia (27 (0-130) µM), antipyretics (40 (30-65) µM) and inhibition of PGE(2) (13 (6-45) µM) were in similar range, whereas inhibition of TXB(2) (5 (4-8) µM) was observed at lower concentrations. Variability in the behavioral measurement of analgesia was larger than for the other endpoints. The inhibition of fever by naproxen was followed by an increased rebound body temperature. CONCLUSION: Due to better sensitivity and similar drug-induced inhibition, the biomarker PGE(2) and the antipyretic effect would be suitable alternative endpoints to the analgesic effects for characterization and comparisons of potency and time-courses of drug candidates affecting the COX-2 pathway and to support human dose projections.