An acute herb-drug interaction of Magnoliae Officinalis Cortex with methotrexate via inhibiting multidrug resistance-associated protein 2.

Magnoliae Officinalis Cortex (MOC), an herbal drug, contains polyphenolic lignans mainly magnolol (MN) and honokiol (HK). Methotrexate (MTX), a critical drug for cancers and autoimmune deseases, is a substrate of multidrug resistance-associated protein 2 (MRP2) and breast cancer resistance protein (BCRP). This study investigated the effect of coadministration of MOC on the pharmacokinetics of MTX and relevant mechanisms. Sprague-Dawley rats were orally administered MTX alone and with single dose (2.0 and 4.0 g/kg) and repeated seven doses of MOC (2.0 g/kg thrice daily for 2 days, the 7th dose given at 0.5 h before MTX). The serum concentrations of MTX were determined by a fluorescence polarization immunoassay. The results showed that a single dose of MOC at 2.0 g/kg significantly increased the AUC0-t and MRT of MTX by 352% and 308%, and a single dose at 4.0 g/kg significantly enhanced the AUC0-t and MRT by 362% and 291%, respectively. Likewise, repeated seven doses of MOC at 2.0 g/kg significantly increased the AUC0-t and MRT of MTX by 461% and 334%, respectively. Mechanism studies indicated that the function of MRP2 was significantly inhibited by MN, HK and the serum metabolites of MOC (MOCM), whereas BCRP was not inhibited by MOCM. In conclusion, coadministration of MOC markedly enhanced the systemic exposure and mean residence time of MTX through inhibiting the MRP2-mediated excretion of MTX.

Viloxazine Increases Extracellular Concentrations of Norepinephrine, Dopamine, and Serotonin in the Rat Prefrontal Cortex at Doses Relevant for the Treatment of Attention-Deficit/Hyperactivity Disorder.

Background: Viloxazine ER (viloxazine extended-release capsules; Qelbree®), a nonstimulant attention-deficit/hyperactivity disorder (ADHD) treatment, has known activity as a norepinephrine (NE) transporter (NET) inhibitor. In vitro studies have also shown direct pharmacological effects on specific serotonin (5-HT) receptors, but not on the serotonin transporter (SERT). An in vivo microdialysis study in rats showed viloxazine (50 mg/kg i.p.) increased extracellular 5-HT, NE, and dopamine (DA) in the prefrontal cortex (PFC), a key brain region in ADHD pathology. This study evaluated whether these effects occur at clinically relevant concentrations. Methods: Microdialysis experiments were conducted in freely-moving, Sprague-Dawley rats (males, 8 weeks). Viloxazine (1, 3, 10, 30 mg/kg) was administered intraperitoneally to establish the dose range in rats at which viloxazine plasma concentrations aligned with those of individuals with ADHD administered therapeutic doses of viloxazine ER. Concentrations of unbound viloxazine, NE, 5-HT, DA, and NE and 5-HT metabolites (3,5-dihydroxyphenylglycol [DHPG] and 5-hydroxyindoleacetic acid [5-HIAA]) were measured in PFC interstitial fluid. After identifying a therapeutically relevant dose (30 mg/kg), the experiment was repeated using 30 and 50 mg/kg viloxazine (as 50 mg/kg increased NE, 5-HT, and DA in prior studies). Results: Viloxazine unbound (free drug) plasma concentrations in rats at 30 mg/kg were comparable to free drug concentrations in individuals with ADHD taking clinically effective doses (based on validated population PK models). Viloxazine 30 mg/kg significantly increased extracellular NE, 5-HT, and DA PFC levels compared to vehicle. Concomitant decreases in DHPG, but not 5-HIAA, support the inhibitory effect of viloxazine on NET but not SERT. Conclusion: At clinically relevant concentrations, viloxazine increases PFC NE, DA, and 5-HT. Prefrontal augmentation of 5-HT does not appear to result from 5-HT reuptake inhibition but may be related to activation of 5-HT neurons. The potential therapeutic role of serotonergic effects in ADHD treatment merits further exploration.

Two curcumin analogs inhibited the function and protein expression of breast cancer resistance protein: in vitro and in vivo studies.

1. Two curcumin analogs, (1E,6E)-1,7-bis(3,5-diethyl-4-hydroxyphenyl)hepta-1,6-diene-3,5- dione (N17) and its prodrug ((1E,6E)-3,5-dioxohepta-1,6-diene-1,7-diyl)bis(2,6-diethyl-4,1- phenylene)bis(3-hydroxy-2-(hydroxymethyl)-2-methylpropanoate) (N17'), were evaluated as breast cancer resistance protein (BCRP) inhibitors.2. MDCKII-BCRP and MDCKII-WT were used to evaluate the modulation effects of N17 and N17' on BCRP and to explore the relevant mechanism. Sprague-Dawley rats were orally administered rosuvastatin (ROS), a probe substrate of BCRP, without and with N17' (100 mg/kg) to investigate the effect of N17' on ROS pharmacokinetics.3. In cell studies, N17 and N17' were substrates of BCRP, and they decreased the activity and protein expression of BCRP. In rat study, N17' increased the systemic exposure of ROS by 218% (p = 0.058).4. N17 and N17' are potential BCRP inhibitors and will be promising candidates for overcoming the BCRP-mediated multidrug resistance.

Cranberry Ingestion Modulated Drug Transporters and Metabolizing Enzymes: Gefitinib Used as a Probe Substrate in Rats.

Cranberry, a polyphenol-rich functional food, is commonly used for the prophylaxis of urinary tract infections. Gefitinib, an anticancer agent clinically prescribed to treat non-small-cell lung cancer, is a substrate of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), and metabolized mainly by cytochrome P450 (CYP) 3A4 and CYP2D6. This study used gefitinib as a probe substrate to investigate the modulation of cranberry on P-gp, BCRP, CYP3A4 and CYP2D6. Rats were administered gefitinib with and without 5.0 g/kg of cranberry as juice (CJ). The concentration of gefitinib in serum was determined by LC-MS/MS. The results showed that CJ significantly increased the Cmax and AUC0-t of gefitinib by 28% and 55%, respectively. Mechanism studies indicated that CJ activated P-gp, and cranberry metabolites (CM) inhibited CYP2D6. Moreover, the protein level of P-gp in rat enterocytes was decreased, whereas that in hepatocytes was increased. In addition, the protein levels of BCRP, CYP3A4 and CYP2D6 in enterocytes and hepatocytes were decreased. In conclusion, CJ ingestion affected the activities and protein levels of P-gp, BCRP, CYP3A4 and CYP2D6.

Magnolol and Honokiol Inhibited the Function and Expression of BCRP with Mechanism Exploration.

Breast cancer resistance protein (BCRP), one of the ATP-binding cassette (ABC) transporters, was associated with the multidrug resistance (MDR) of chemotherapy. Magnolol (MN) and honokiol (HK) are major bioactive polyphenols of Magnolia officinalis. This study investigated the effects of MN and HK on the function and expression of BCRP for the purpose of developing BCRP inhibitor to overcome MDR. Cell lines including MDCKII-BCRP and MDCKII-WT were used for evaluating the function and expression of BCRP. The results showed that MN (100-12.5 µM) and HK (100-12.5 µM) significantly decreased the function of BCRP by 80~12% and 67~14%, respectively. In addition, MN and HK were verified as substrates of BCRP. Furthermore, MN and HK reduced the protein expression of BCRP, and inhibited the phosphorylation of epidermal growth factor receptor (EGFR) and phosphatidylinositol 3-kinase (PI3K). In conclusion, both MN and HK decreased the function and expression of BCRP via EGFR/PI3K signaling pathway. Therefore, both compounds were promising candidates for reversing the MDR of chemotherapy.

Folium Sennae Increased the Bioavailability of Methotrexate through Modulation on MRP 2 and BCRP.

Folium Sennae (FS), a popular laxative (Senna), contains polyphenolic anthranoids, whose conjugation metabolites are probable modulators of multidrug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP). We suspected that the combined use of FS might alter the pharmacokinetics of various medicines transported by MRPs or BCRP. This study investigated the effect of FS on the pharmacokinetics of methotrexate (MTX), an anticancer drug and a probe substrate of MRPs/BCRP. Rats were orally administered MTX alone and with two dosage regimens of FS in a parallel design. The results show that 5.0 g/kg of FS significantly increased the AUC0-2880, AUC720-2880 and MRT of MTX by 45%, 102% and 42%, and the seventh dose of 2.5 g/kg of FS significantly enhanced the AUC720-2880 and MRT by 78% and 42%, respectively. Mechanism studies indicated that the metabolites of FS (FSM) inhibited MRP 2 and BCRP. In conclusion, the combined use of FS increased the systemic exposure and MRT of MTX through inhibition on MRP 2 and BCRP.

Bidirectional Influences of Cranberry on the Pharmacokinetics and Pharmacodynamics of Warfarin with Mechanism Elucidation.

Cranberry is a dietary supplement popularly used for the prophylaxis of urinary tract infection. Interestingly, cranberry-warfarin interactions in clinical reports have shown bidirectional outcomes. (±) Warfarin, a widely prescribed anticoagulant, but with a narrow therapeutic index, contains equal amounts of S- and R-warfarin, of which S-warfarin is more active. The aim of this study was to investigate the effects of different ingestion times of cranberry on the pharmacokinetics and pharmacodynamics of warfarin. Rats were orally administered (±) warfarin (0.2 mg/kg) with and without cranberry (5.0 g/kg) at 0.5 h prior to the warfarin, and at 10 h after the warfarin. The plasma concentrations of S- and R-warfarin were determined by LC/MS. The results indicate that cranberry ingested at 0.5 h before (±) warfarin significantly decreased the systemic exposures of S-warfarin and R-warfarin. Conversely, when cranberry was ingested at 10 h after (±) warfarin, the elimination of S-warfarin was significantly inhibited, and the anticoagulation effect of (±) warfarin was significantly enhanced. The results of the mechanism studies indicate that cranberry activated the breast cancer resistance protein (BCRP), which mediated the efflux transports of S-warfarin and R-warfarin. Moreover, the metabolites of cranberry inhibited cytochrome P450 (CYP) 2C9, the main metabolizing enzyme for S-warfarin. In conclusion, cranberry affected the pharmacokinetics of (±) warfarin in a bidirectional manner by activating the BCRP by CJ during absorption and inhibiting the BCRP and CYP2C9 by CMs during elimination, depending on the ingestion time of CJ. The combined use of cranberry with warfarin should be avoided.

Viloxazine in the Management of CNS Disorders: A Historical Overview and Current Status.

Viloxazine has a long history of clinical use in Europe as an antidepressant, and has recently been repurposed into an extended-release form for the treatment of attention-deficit/hyperactivity disorder in the USA. An immediate-release formulation was approved for the treatment of depression in the UK in 1974, and was subsequently marketed there and in several European countries for 30 years with no major safety concerns. In contrast to first-generation antidepressants (e.g., tricyclic antidepressants, monoamine oxidase inhibitors), viloxazine was associated with a relatively low risk for cardiotoxicity. Gastrointestinal symptoms were the most commonly reported side effects. The therapeutic effects of viloxazine are thought to be primarily the result of its action as a norepinephrine reuptake inhibitor, although in vitro and preclinical in vivo animal data suggest that viloxazine may also impact the serotoninergic system. This review summarizes the evolving knowledge of viloxazine based on information from previously published preclinical and clinical investigations, and acquired unpublished historical study reports from both open-label and blinded controlled clinical trials. We review the chemical properties, mechanism of action, safety, and tolerability across these studies, and discuss the contemporary rationale for the development of this agent as an extended-release oral formulation for the treatment of attention-deficit/hyperactivity disorder.

New Insights into the Mechanism of Action of Viloxazine: Serotonin and Norepinephrine Modulating Properties.

BACKGROUND: Viloxazine was historically described as a norepinephrine reuptake inhibitor (NRI). Since NRIs have previously demonstrated efficacy in attention deficit/hyperactivity disorder (ADHD), viloxazine underwent contemporary investigation in the treatment of ADHD. Its clinical and safety profile, however, was found to be distinct from other ADHD medications targeting norepinephrine reuptake. Considering the complexity of neuropsychiatric disorders, understanding the mechanism of action (MoA) is an important differentiating point between viloxazine and other ADHD medications and provides pharmacology-based rationale for physicians prescribing appropriate therapy. METHODS: Viloxazine was evaluated in a series of in vitro binding and functional assays. Its effect on neurotransmitter levels in the brain was evaluated using microdialysis in freely moving rats. RESULTS: We report the effects of viloxazine on serotoninergic (5-HT) system. In vitro, viloxazine demonstrated antagonistic activity at 5-HT2B and agonistic activity at 5-HT2C receptors, along with predicted high receptor occupancy at clinical doses. In vivo, viloxazine increased extracellular 5-HT levels in the prefrontal cortex (PFC), a brain area implicated in ADHD. Viloxazine also exhibited moderate inhibitory effects on the norepinephrine transporter (NET) in vitro and in vivo, and elicited moderate activity at noradrenergic and dopaminergic systems. CONCLUSION: Viloxazine's ability to increase 5-HT levels in the PFC and its agonistic and antagonistic effects on certain 5-HT receptor subtypes, which were previously shown to suppress hyperlocomotion in animals, indicate that 5-HT modulating activity of viloxazine is an important (if not the predominant) component of its MoA, complemented by moderate NET inhibition. Supported by clinical data, these findings suggest the updated psychopharmacological profile of viloxazine can be best explained by its action as a serotonin norepinephrine modulating agent (SNMA).

Resveratrol stereoselectively affected (±)warfarin pharmacokinetics and enhanced the anticoagulation effect.

Resveratrol (RVT) has various beneficial bioactivities and popularly used as a dietary supplement. RVT showed inhibitions on CYP1A2/2C9/3A4, breast cancer resistance protein (BCRP), and some conjugated metabolites of RVT also inhibited BCRP. (±)Warfarin, an anticoagulant for cardiovascular disease but with narrow therapeutic window, were substrates of CYP1A2/3A4(R-form), 2C9(S-form) and BCRP. We hypothesized that the concurrent use of RVT might affect the metabolism and excretion of warfarin. This study investigated the effect of RVT on the pharmacokinetics and anticoagulation effect of (±)warfarin. Rats were orally given (±)warfarin (0.2 mg/kg) without and with RVT (100 mg/kg) in a parallel design. The results showed that RVT significantly increased the AUC0-t of S-warfarin and international normalized ratio. Mechanism studies showed that both RVT and its serum metabolites (RSM) inhibited BCRP-mediated efflux of R- and S-warfarin. Moreover, RSM activated CYP1A2/3A4, but inhibited CYP2C9. In conclusion, concomitant intake of RVT increased the systemic exposure of warfarin and enhanced the anticoagulation effect mainly via inhibitions on BCRP and CYP2C9.

Metabolism and in vitro drug-drug interaction assessment of viloxazine.

Viloxazine is currently being developed as a treatment for attention deficit/hyperactivity disorder (ADHD). The aim of these studies is to update the understanding of the rat and human metabolism and the in vitro drug-drug interaction profile of viloxazine to a degree where it meets current regulatory standards for such investigations. In vivo absorption-distribution-metabolism-excretion (ADME) studies demonstrated that in humans 5-hydroxylation followed by glucuronidation is the major metabolic route. This route was also seen as a minor route in rats where the major route is O-deethylation with subsequent sulfation. In humans, the 5-hydoxylation pathway is mediated by CYP2D6. An estimate for the fraction of the metabolism via this pathway suggests a PM/EM difference of <2-fold, making it highly unlikely that this will be an issue of clinical significance. Viloxazine forms a unique N-carbamoyl glucuronide in humans. The chemical reactivity characteristics of this metabolite are similar to stable glucuronide conjugates and dissimilar from acyl glucuronides; therefore, it is regarded as a stable Phase II conjugate. In vitro drug-drug interaction (DDI) testing indicates that viloxazine is not a significant inhibitor or inducer of CYPs and transporters with the exception of CYP1A2.

Near-complete regression 19 years after Gamma Knife radiosurgery of vestibular schwannoma with massive pseudoprogression: case report.

Gamma Knife radiosurgery (GKRS) is a frequent treatment choice for patients with small- to moderate-sized vestibular schwannoma (VS). However, pseudoprogression after GKRS is commonly observed, with a reported incidence ranging from 7% to 77%. The wide range of the reported incidence of pseudoprogression reflects the fact that there is no consensus on how it should be diagnosed. The authors present the case of a 66-year-old woman who had a 2.5-cm right-sided VS treated with GKRS in 1997. The first posttreatment MRI obtained 5 months later showed that the tumor volume had increased to 9.7 cm3. The tumor volume increased further and reached its peak 24 months after treatment at 20.9 cm3, which was a 161% increase from pretreatment volume. Thereafter, the tumor shrank gradually and mass effect on the brainstem reduced over time. By 229 months after treatment, the tumor volume was 1.0 cm3, equaling 12.5% of pretreatment tumor volume, or 4.8% of peak tumor volume after treatment. This case demonstrates that if a patient remains asymptomatic despite a dramatic increase in tumor volume after GKRS, observation remains an option, because even a very sizable tumor can shrink with near-complete resolution. Patients undergoing GKRS for VS should be counseled regarding the possibility of pseudoprogression, and followed carefully over time while avoiding premature decisions for surgical removal after treatment.

Effects of antibiotics on the pharmacokinetics of indoxyl sulfate, a nephro-cardiovascular toxin.

Indoxyl sulfate (IS), a highly protein-bound nephro-cardiovascular toxin, was poorly removed by hemodialysis. IS exists as anions in the body and the renal excretion is mediated by organic anion transporter 1 (OAT1) and OAT3. Acidic antibiotics such as cephalosporins and fluoroquinolones were putative substrates/inhibitors of OATs. We hypothesized that cephalosporins and fluoroquinolones might compete with IS for OAT1- and/or OAT3-mediated renal excretions.This study investigated the effects of ciprofloxacin, cefuroxime, cefotaxime, cefazolin and ofloxacin on the intravenous pharmacokinetics of IS in rats. IS was intravenously injected with and without each individual antibiotics, and the concentrations of IS in serum and lysate were determined by HPLC.The results showed that ciprofloxacin significantly increased AUC0-t and T1/2 of IS by 272% and 491%, respectively, and decreased the clearance by 71%. However, ofloxacin, cefuroxime, cefotaxime and cefazolin did not alter the pharmacokinetics of IS. Furthermore, cell line study showed that ciprofloxacin inhibited the OAT3-mediated transport of IS.This study indicates 30 mg/kg of ciprofloxacin decreased the clearance of IS through inhibition on the OAT3-mediated transport, whereas 50 mg/kg of ofloxacin, cefuroxime, cefotaxime and cefazolin did not show significant influence.

A proposed anti-maladaptive aggression agent classification: improving our approach to treating impulsive aggression.

Proper drug categorization enables clinicians to readily identify the agents most appropriate for patients in need. Currently, patients with maladaptive aggression do not all always fall into a single existing diagnostic or treatment category. Such is the case for those with impulsive aggression (IA). IA is an associated feature of numerous neuropsychiatric disorders, and can be described as eruptive, aggressive behavior or a 'short fuse'. Although agents from a broad spectrum of drug classes have been used to treat maladaptive aggression, few have been tested distinctly in patients with IA, and there is no drug specifically indicated by the US Food and Drug Administration (US FDA) for IA. Further, current treatments often fail to sufficiently treat IA symptomatology. These issues create an unclear and inadequate treatment path for patients. Here we will propose the establishment of a class of anti-maladaptive aggression agents to begin addressing this clinical issue. The development of such a class would unify the various drugs currently used to treat maladaptive aggression and streamline the treatment approach towards IA. As an important case example of the range of candidate drugs that could fit into a new anti-maladaptive aggression agent category, we will review an investigational IA pharmacotherapy. SPN-810 (extended-release molindone) is currently being investigated as a novel treatment for children with IA and ADHD. Based on these studies we will review how SPN-810 may be well suited for a new, anti-maladaptive aggression drug class and more precisely, a proposed subgroup of IA modulators. The goal of this review is to begin improving the identification of and therapeutic approach for maladaptive aggression as well as IA through more precise anti-maladaptive aggression agent categorization.

In vitro pharmacological characterization of SPN-810M (molindone).

BACKGROUND: Impulsive aggression (IA) is considered a maladaptive form of aggression that is reactive and overt and occurs outside of the acceptable social context. Many children and adolescents with attention-deficit/hyperactivity disorder (ADHD) display clinically significant aggression, with the predominant subtype being IA. However, there is currently no Food and Drug Administration-approved medication specifically to treat IA. The pathophysiology of IA is not fully understood, although it has been suggested to include the dopamine, norepinephrine, and serotonin systems. METHODS: SPN-810 (extended-release molindone) is being developed for the novel indication of IA and is currently being studied in patients treated for ADHD. Molindone is an indole derivative and a dopamine D2 receptor antagonist. RESULTS: The in vitro pharmacological studies described in the current manuscript demonstrate that the active substance molindone (SPN-810M) is a potent antagonist for the dopamine receptors, D2S and D2L, and the serotonin receptor, 5-HT2B, at therapeutic concentrations. The in vitro studies further demonstrate that the antagonist effect of SPN-810M is due to the parent drug and not the metabolites, and that the antagonism is not affected by the presence of norepinephrine or dopamine neurotransmitters. In addition, studies investigating the potential differential effects of the enantiomers of SPN-810M have demonstrated that the R(-) enantiomer is more potent than S(+), showing greater regulatory effect on D2S and D2L receptors. CONCLUSION: Overall, the results of the in vitro SPN-810M pharmacological studies provide some insight into how SPN-810M modulates the serotonin and dopamine pathways that play a role in IA.

Reproductive toxicology studies supporting the safety of molindone, a dopamine receptor antagonist.

BACKGROUND: An extended-release molindone (a dopamine D2 and serotonin antagonist) is currently being developed as a novel treatment for impulsive aggression (IA) in patients optimally treated for ADHD. Oral Good Laboratory Practice reproductive toxicology studies (fertility and early embryonic [FEE], prenatal/postnatal [PPN], embryo-fetal development [EFD]) were conducted with molindone HCl using International Conference on Harmonisation (ICH) S5(R2)-compliant protocols. METHODS: In the FEE study, 0, 5, 15, or 30 mg kg-1 day-1 was administered to female (2 weeks premating through implantation) and male (4 weeks premating for 57 days) rats, and fertility parameters were evaluated. In the EFD studies, rats received 0, 5, 20, or 40 mg kg-1 day-1 on gestational days (GDs) 6-17; rabbits received 0, 5, 10, or 15 mg kg-1 day-1 on GDs 6-18. Ovarian/uterine and fetal parameters were evaluated at term. In the PPN study, F0 rats received 0, 5, 20, or 40 mg kg-1 day-1 (GD6-LD21); behavior and reproduction were evaluated in F1 offspring. RESULTS: Parental hypoactivity and reduced body weight gain occurred in all studies. In the FEE, prolonged estrous cycles and delayed mating occurred at ≥15 mg kg-1 day-1 , without effects on fertility or embryonic development. No developmental toxicity occurred in F1 fetuses. In F1 pups, reduced preweaning growth was observed at 40 mg kg-1 day-1 , but there were no effects on postweaning growth, behavior, or reproduction. CONCLUSIONS: Molindone was not developmentally toxic in rats or rabbits at 69X and 6X clinical exposures, confirming the reproductive safety of molindone. Changes in estrous cyclicity were related to species-specific pharmacological effects of molindone in rodents and are not considered relevant to human risk.

Activation of P-glycoprotein and CYP 3A by Coptidis Rhizoma in vivo: Using cyclosporine as a probe substrate in rats.

Coptidis Rhizoma (CR), the rhizome of Coptis chinensis FRANCH, is a popular Chinese herb. CR contains plenty of isoquinoline alkaloids such as berberine, coptisine and palmatine. Cyclosporine (CSP), an important immunosuppressant with narrow therapeutic window, is employed as a probe substrate of P-glycoprotein (P-gp) and CYP3A4 in order to investigate the in vivo modulation effect of CR on P-gp and CYP3A4. Three groups of rats were orally administered CSP without and with single dose or repeated dosing of CR in a parallel design. Blood samples were collected at specific time points and the blood CSP concentration was determined by a specific monoclonal fluorescence polarization immunoassay. The results showed that a single dose (1.0 g/kg) and the 7th dose (1.0 g/kg) of CR significantly decreased the Cmax of CSP by 56.9% and 70.4%, and reduced the AUC0-540 by 56.4% and 68.7%, respectively. Cell study indicated that CR decoction, berberine, coptisine, palmatine all activated the efflux transport of P-gp. Ex-vivo study showed that the serum metabolites of CR activated CYP 3A4. In conclusion, through using CSP as an in vivo probe substrate, we have verified that oral intake of CR activated the functions of P-gp and CYP3A based on in vivo and in vitro studies.

Transporter-mediated interaction of indican and methotrexate in rats.

Indican (indoxyl-ß-D-glucoside) is present in several Chinese herbs e.g. Isatis indigotica, Polygonum tinctorium and Polygonum perfoliatum. The major metabolite of indican was indoxyl sulfate (IS), an uremic toxin which was a known substrate/inhibitor of organic anion transporter (OAT) 1, OAT 3 and multidrug resistance-associated protein (MRP) 4. Methotrexate (MTX), an important immunosuppressant with narrow therapeutic window, is a substrate of OAT 1, 2, 3, 4 and MRP 1, 2, 3, 4. We hypothesized that IS, the major metabolite of oral indican, might inhibit the renal excretion of MTX mediated by OAT 1, OAT 3 and MRP 4. Therefore, this study investigated the effect of oral indican on the pharmacokinetics of MTX. Rats were orally given MTX with and without indican (20.0 and 40.0 mg/kg) in a parallel design. The serum MTX concentration was determined by a fluorescence polarization immunoassay. For mechanism clarification, phenolsulfonphthalein (PSP, 5.0 mg/kg), a probe substrate of OAT 1, OAT 3, MRP 2 and MRP 4, was intravenously given to rats with and without a intravenous bolus of IS (10.0 mg/kg) to measure the effect of IS on the elimination of PSP. The results indicated that 20.0 and 40.0 mg/kg of oral indican significantly increased the area under concentration-time curve0-t (AUC0-t) of MTX by 231% and 259%, prolonged the mean residence time (MRT) by 223% and 204%, respectively. Furthermore, intravenous IS significantly increased the AUC0-t of PSP by 204% and decreased the Cl by 68%. In conclusion, oral indican increased the systemic exposure and MRT of MTX through inhibition on multiple anion transporters including OAT 1, OAT 3 and MRP 4 by the major metabolite IS.

Aloe Metabolites Prevent LPS-Induced Sepsis and Inflammatory Response by Inhibiting Mitogen-Activated Protein Kinase Activation.

Aloe, a polyphenolic anthranoid-containing Aloe vera leaves, is a Chinese medicine and a popular dietary supplement worldwide. In in vivo situations, polyphenolic anthranoids are extensively broken down into glucuronides and sulfate metabolites by the gut and the liver. The anti-inflammatory potential of aloe metabolites has not been examined. The aim of this study was to investigate the anti-inflammatory effects of aloe metabolites from in vitro (lipopolysaccharides (LPS)-activated RAW264.7 macrophages) and ex vivo (LPS-activated peritoneal macrophages) to in vivo (LPS-induced septic mice). The production of proinflammatory cytokines (TNF-[Formula: see text] and IL-12) and NO was determined by ELISA and Griess reagents, respectively. The expression levels of iNOS and MAPKs were analyzed by Western blot. Our results showed that aloe metabolites inhibited the expression of iNOS, decreased the production of TNF-[Formula: see text], IL-12, and NO, and suppressed the phosphorylation of MAPKs by LPS-activated RAW264.7 macrophages. In addition, aloe metabolites reduced the production of NO, TNF-[Formula: see text] and IL-12 by murine peritoneal macrophages. Furthermore, aloe administration significantly reduced the NO level and exhibited protective effects against sepsis-related death in LPS-induced septic mice. These results suggest that aloe metabolites exerted anti-inflammatory effects in vivo, and that these effects were associated with the inhibition of inflammatory mediators. Therefore, aloe could be considered an effective therapeutic agent for the treatment of sepsis.