scholarly journals Organic Anion Transporting Polypeptides 1B1 and 1B3 Play an Important Role in Uremic Toxin Handling and Drug-Uremic Toxin Interactions in the Liver

2014 ◽  
Vol 17 (4) ◽  
pp. 475 ◽  
Author(s):  
Toshihiro Sato ◽  
Hiroaki Yamaguchi ◽  
Takuma Kogawa ◽  
Takaaki Abe ◽  
Nariyasu Mano
Keyword(s):  
Chronic Kidney Disease ◽  
Kynurenic Acid ◽  
Organic Anion ◽  
Uremic Toxins ◽  
Uremic Toxin ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Concentration Dependent Manner ◽  
Uptake Studies ◽  
Indole 3 Acetic Acid

PURPOSE. Organic anion-transporting polypeptide (OATP) 1B1 and OATP1B3 contribute to hepatic uptake of numerous drugs. Thus, reduced OATP1B1 and OATP1B3 activity in chronic kidney disease (CKD) may have a major impact on the hepatic clearance of drugs. The effect of drug-uremic toxin interactions on OATP1B1 and OATP1B3 has not been well studied. In the present study, we examine the inhibitory effects of uremic toxins on OATP1B1 and OATP1B3 transport activity to evaluate the interactions between drugs and uremic toxins in patients with chronic kidney disease. METHODS. [3H]Estron-3-sulfate, [3H]taurocholate uptake and [3H]methotrexate by OATP1B1 and OATP1B3 expressing HEK293 cells were performed to evaluate the inhibitory effect of uremic toxins. To clarify whether the uremic toxins that interact with OATP1B1 and/or OATP1B3 were substrates for these transporters, we performed uptake studies. RESULTS. Four uremic toxins, kynurenic acid, indole-3-acetic acid, indoxyl sulfate, and p-cresol, inhibited OATP1B1- and OATP1B3-mediated transport in a concentration-dependent manner, with IC50 values of 180, 770, 2700, and 4600 µM, respectively, for OATP1B1 and 180, 1100, 1300, and 1700 µM, respectively, for OATP1B3. [3H]Methotrexate uptake by OATPs was also inhibited by the four uremic toxins in a dose-dependent manner. Uptake studies revealed that kynurenic acid is a substrate for both the OATP1B1 and OATP1B3. Moreover, OATP1B3 was involved in the transport of indoxyl sulfate. Indole-3-acetic acid and p-cresol were not significantly transported by OATP1B1 and OATP1B3. CONCLUSIONS. We showed that some uremic toxins inhibit OATP-mediated uptake in a concentration-dependent manner, and clarified OATPs contribution to uremic toxin handling in the liver. Thus, we provided basic information to estimate the inhibitory effects of uremic toxins on OATPs in CKD patients. These data suggest that the dose of drugs excreted via renal and non-renal pathways should be carefully adjusted in CKD patients.This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

scholarly journals Uremic Toxins and Frailty in Patients with Chronic Kidney Disease: A Molecular Insight

2021 ◽  
Vol 22 (12) ◽  
pp. 6270
Author(s):  
Chia-Ter Chao ◽  
Shih-Hua Lin
Keyword(s):  
Chronic Kidney Disease ◽  
Renal Function ◽  
Kidney Disease ◽  
Uremic Toxins ◽  
Heme Oxygenase 1 ◽  
Signal Pathways ◽  
Uremic Toxin ◽  
Nuclear Factor ◽  
Cognitive Frailty ◽  
Renal Function Decline

The accumulation of uremic toxins (UTs) is a prototypical manifestation of uremic milieu that follows renal function decline (chronic kidney disease, CKD). Frailty as a potential outcome-relevant indicator is also prevalent in CKD. The intertwined relationship between uremic toxins, including small/large solutes (phosphate, asymmetric dimethylarginine) and protein-bound ones like indoxyl sulfate (IS) and p-cresyl sulfate (pCS), and frailty pathogenesis has been documented recently. Uremic toxins were shown in vitro and in vivo to induce noxious effects on many organ systems and likely influenced frailty development through their effects on multiple preceding events and companions of frailty, such as sarcopenia/muscle wasting, cognitive impairment/cognitive frailty, osteoporosis/osteodystrophy, vascular calcification, and cardiopulmonary deconditioning. These organ-specific effects may be mediated through different molecular mechanisms or signal pathways such as peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α), mitogen-activated protein kinase (MAPK) signaling, aryl hydrocarbon receptor (AhR)/nuclear factor-κB (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), Runt-related transcription factor 2 (RUNX2), bone morphogenic protein 2 (BMP2), osterix, Notch signaling, autophagy effectors, microRNAs, and reactive oxygen species induction. Anecdotal clinical studies also suggest that frailty may further accelerate renal function decline, thereby augmenting the accumulation of UTs in affected individuals. Judging from these threads of evidence, management strategies aiming for uremic toxin reduction may be a promising approach for frailty amelioration in patients with CKD. Uremic toxin lowering strategies may bear the potential of improving patients’ outcomes and restoring their quality of life, through frailty attenuation. Pathogenic molecule-targeted therapeutics potentially disconnect the association between uremic toxins and frailty, additionally serving as an outcome-modifying approach in the future.

Abstract 17220: Effects of the Oral Adsorbent of AST-120 in Patients with both Chronic Heart Failure and Chronic Kidney Disease

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Miki Imazu ◽  
Masanori Asakura ◽  
Takuya Hasegawa ◽  
Hiroshi Asanuma ◽  
Shin Ito ◽  
...  
Keyword(s):  
Heart Failure ◽  
Chronic Kidney Disease ◽  
Chronic Heart Failure ◽  
Kidney Disease ◽  
Diastolic Dysfunction ◽  
Uremic Toxins ◽  
Control Group ◽  
Blood Levels ◽  
Uremic Toxin ◽  
Oral Adsorbent

Background: One of uremic toxins, indoxyl sulfate (IS) is related to the progression of chronic kidney disease (CKD) and the worse cardiovascular outcomes. We have previously reported the relationship between IS levels and the severity of chronic heart failure (CHF), but the question arises as to whether the treatment of uremic toxin is beneficial in patients with CHF. This study aimed to elucidate whether the treatment with the oral adsorbent which reduces uremic toxin improved the cardiac function of the patients with CHF. Methods: First of all, we retrospectively enrolled 49 patients with both CHF and stage ≤3 CKD in our institute compared with the healthy subjects without CHF or CKD in the resident cohort study of Arita. Secondly, we retrospectively enrolled 16 CHF outpatients with stage 3-5 CKD. They were treated with and without the oral adsorbent of AST-120 for one year termed as the treatment and control groups, respectively. We underwent both blood test and echocardiography before and after the treatment. Results: First of all, among 49 patients in CHF patients, plasma IS levels increased to 1.38 ± 0.84 μg/ml from the value of 0.08 ± 0.06 μg/ml in Arita-cho as a community-living matched with gender and eGFR of CHF patients. We found both fractional shortening (FS) and E/e’, an index of diastolic function were decreased (25.0 ± 12.7%) and increased (13.7 ± 7.5), respectively in CHF patients compared with the value of FS and E/e’ in Arita-cho (FS: 41.8 ± 8.3%, E/e’: 8.8 ± 2.1). Secondly, in the treatment group, the plasma IS levels and the serum creatinine and brain natriuretic peptide levels decreased (1.40 ± 0.17 to 0.92 ± 0.15 μg/ml; p<0.05, 1.91 ± 0.16 to 1.67 ± 0.12 mg/dl; p<0.05, 352 ± 57 to 244 ± 49 pg/ml; p<0.05, respectively) and both FS and E/e’ were improved following the treatment with AST-120 (28.8 ± 2.8 to 32.9 ± 2.6%; p<0.05, 18.0 ± 2.0 to 11.8 ± 1.0; p<0.05). However, these parameters did not change in the control group. Conclusions: The treatment to decrease the blood levels of uremic toxins improved not only renal dysfunction but cardiac systolic and diastolic dysfunction in patients with chronic heart failure. Oral adsorbents might be a new treatment of heart failure especially with diastolic dysfunction.

MO448MICRORNAS IMPLICATED IN CHRONIC KIDNEY DISEASE

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Laurent Metzinger
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Clinical Outcomes ◽  
Molecular Mechanisms ◽  
Neointimal Hyperplasia ◽  
Uremic Toxins ◽  
University Hospital ◽  
Transcriptional Level ◽  
Uremic Toxin ◽  
Ckd Stage

Abstract Background and Aims The gene program is controlled at the post-transcriptional level by the action of small non-coding RNAs known as microRNAs (miRNAs), short, single-stranded molecules that control mRNA stability or translational repression via base pairing with regions in the 3' untranslated region of their target mRNAs. Recently, considerable progress has been made to elucidate the roles of miRNAs in vascular pathogenesis and develop the use of miRNAs as biomarkers, and innovative drugs. We demonstrated during the last decade that miRNAs miR-126 and miR-223 are implicated in the course of chronic kidney disease (CKD) and cardiovascular damage. miR-223 expression is enhanced in vascular smooth muscle cells (VSMCs) subjected to an uremic toxin and also in aortas of a murine model of CKD. As restenosis is a common complication of angioplasty, in which neointimal hyperplasia results from migration of VSMCs into the vessel lumen we measured the effect of miR-223 modulation on restenosis in a rat model of carotid artery after balloon injury. We over-expressed and inhibited miR-223 expression using adenoviral vectors, coding a pre-miR-223 sequence or a sponge sequence, used to trap endogenous microRNA, respectively. We demonstrated that inhibiting miR-223 function significantly reduced neointimal hyperplasia by almost half in carotids. Thus down-regulating miR-223 could be a potential therapeutic approach to prevent restenosis after angioplasty. We also correlated miR-126 and miR-223 expression with clinical outcomes in a large cohort of CKD patients, in collaboration with the University Hospital of Ghent (Belgium) and Ambroise Paré Hospital, France. We evaluated both miRNA’s link with all-cause mortality and cardiovascular and renal events over a 6-year follow-up period. The serum levels of miR-126 and miR-223 were decreased as CKD stage advanced, and patients with higher levels of miR-126 and miR-223 had a higher survival rate. Similar results were observed for cardiovascular and renal events. In conclusion, CKD is associated with a decrease in circulating miR-126 and miR-223 levels in CKD patients. We will also present links between several uremic toxin concentrations and miRNA concentration in the patients of this cohort. Finally, anemia is a common feature of CKD that is associated with cardiovascular disease and poor clinical outcomes. A mixture of uremic toxins accumulates in the blood of CKD patients during the course of the disease, and there is good evidence that they modulate erythropoiesis, explaining at least partly anemia. The exact molecular mechanisms implicated are however poorly understood, although recent progresses have been made to identify key components in the CKD process. We will present results on the effect of uremic toxins on erythropoiesis, having an impact on cell metabolism during this process. Taken together, our findings could be of interest to both researchers and clinicians working in the field since they might shed new light on the molecular mechanisms involved in the CKD process. MicroRNAs implicated in Chronic Kidney Disease Pr. Laurent Metzinger, UR-UPJV 4666 HEMATIM, CURS, Université de Picardie Jules Verne, CHU Amiens Sud, Avenue René Laënnec, Salouel, F-80054, Amiens, France. Tel: (+33) 22 82 53 56, Email: [email protected]

scholarly journals Twenty Traditional Algerian Plants Used in Diabetes Therapy as Strong Inhibitors of α-Amylase Activity

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Ihcen Khacheba ◽  
Amar Djeridane ◽  
Mohamed Yousfi
Keyword(s):  
Amylase Activity ◽  
Aluminium Chloride ◽  
Total Phenolic ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Concentration Dependent Manner ◽  
Diabetes Therapy ◽  
Methanolic Extracts ◽  
Phenolic Extract ◽  
Gallic Acid Equivalent

In the present work, we have studied the inhibitory effects of aqueous and alcoholic extracts of six Algerian medicinal plants known by their therapeutic virtues against diabetes. The total phenolic compounds content, assayed using Folin-Ciocalteu’s reagent, of the samples ranged from 0.183 mg/g to 43.088 mg/g and from 1.197 mg/g to 7.445 mg/g, expressed as gallic acid equivalent (GAE), for the, respectively, whereas the total flavonoids concentrations, detected using 2% of the aluminium chloride, ranged from 0.41 mg/g to 11.613 mg/g and from 0.0097 mg/g to 1.591 mg/g, expressed as rutin equivalents (RE), for the aqueous and methanolic extracts, respectively. The major plants were found to inhibit enzymatic activities of Aspergillus oryzae-amylase in a concentration dependent manner. The values of the inhibition constants (Ki) have been determined according to the Dixon and Lineweaver-Burk methods. The results showed that the Ki values were less than 55 ppm for the all extracts. A strong inhibition was found in the phenolic extract of Salvia officinalis with a Ki of 8 ppm.

Comparative Effects of Bupivacaine and Ropivacaine on Intracellular Calcium Transients and Tension in Ferret Ventricular Muscle

2004 ◽  
Vol 101 (4) ◽  
pp. 888-894 ◽  
Author(s):  
Yasushi Mio ◽  
Norio Fukuda ◽  
Yoichiro Kusakari ◽  
Yoshikiyo Amaki ◽  
Yasumasa Tanifuji ◽  
...  
Keyword(s):  
Inhibitory Effect ◽  
Bay K 8644 ◽  
Clinical Settings ◽  
Ca Channel ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Concentration Dependent Manner ◽  
Intracellular Ca ◽  
Slope Difference ◽  
The Relationship

Background Recent evidence suggests that ropivacaine exerts markedly less cardiotoxicity compared with bupivacaine; however, the mechanisms are not fully understood at the molecular level. Methods Isolated ferret ventricular papillary muscles were microinjected with the Ca-binding photoprotein aequorin, and intracellular Ca transients and tension were simultaneously measured during twitch in the absence and presence of bupivacaine or ropivacaine. Results Bupivacaine and ropivacaine (10, 30, and 100 microm) reduced peak systolic [Ca]i and tension in a concentration-dependent manner. The effects were significantly greater for bupivacaine, particularly on tension (approximately twofold). The percentage reduction of tension was linearly correlated with that of [Ca]i for both anesthetics, with the slope of the relationship being approximately equal to 1.0 for ropivacaine and approximately equal to 1.3 for bupivacaine (slope difference, P &lt; 0.05), suggesting that the cardiodepressant effect of ropivacaine results predominantly from inhibition of Ca transients, whereas bupivacaine suppresses Ca transients and the reaction beyond Ca transients, i.e., myofibrillar activation, as well. BAY K 8644, a Ca channel opener, abolished the inhibitory effects of ropivacaine on Ca transients and tension, whereas BAY K 8644 only partially inhibited the effects of bupivacaine, particularly the effects on tension. Conclusion The cardiodepressant effect of bupivacaine is approximately twofold greater than that of ropivacaine. Bupivacaine suppresses Ca transients more markedly than does ropivacaine and reduces myofibrillar activation, which may at least in part underlie the greater inhibitory effect of bupivacaine on cardiac contractions. These results suggest that ropivacaine has a more favorable profile as a local anesthetic in the clinical settings.

scholarly journals Advanced oxidation protein products downregulate CYP1A2 and CYP3A4 expression and activity via the NF-κB-mediated signaling pathway in vitro and in vivo

2021 ◽  
Author(s):  
Tianrong Xun ◽  
Zhufen Lin ◽  
Xiaokang Wang ◽  
Xia Zhan ◽  
Haixing Feng ◽  
...  
Keyword(s):  
Liver Microsomes ◽  
Advanced Oxidation ◽  
Uremic Toxins ◽  
Uremic Toxin ◽  
Dependent Manner ◽  
Advanced Oxidation Protein Products ◽  
Protein Levels ◽  
Cyp3a4 Expression

AbstractUremic toxin accumulation is one possible reason for alterations in hepatic drug metabolism in patients with chronic kidney disease (CKD). However, the types of uremic toxins and underlying mechanisms are poorly understood. In this study, we report the role of advanced oxidation protein products (AOPPs), a modified protein uremic toxin, in the downregulation of cytochromes P450 1A2 (CYP1A2) and P450 3A4 (CYP3A4) expression levels and activities. We found that AOPP accumulation in plasma in a rat CKD model was associated with decreased protein levels of CYP1A2 and CYP3A4. CYP1A2 and CYP3A4 metabolites (acetaminophen and 6β-hydroxytestosterone, respectively,) in liver microsomes were also significantly decreased. In human hepatocytes, AOPPs significantly decreased CYP1A2 and CYP3A4 protein levels in a dose- and time-dependent manner and downregulated their activities; however, bovine serum albumin (BSA), a synthetic precursor of AOPPs, had no effect on these parameters. The effect of AOPPs was associated with upregulation of p-IKKα/β, p-IκBα, p-NF-κB, and inflammatory cytokines protein levels and increases in p-IKKα/β/IKKα, p-IκBα/IκBα, and p-NF-κB/NF-κB phosphorylation ratios. Further, NF-kB pathway inhibitors BAY-117082 and PDTC abolished the downregulatory effects of AOPPs. These findings suggest that AOPPs downregulate CYP1A2 and CYP3A4 expression and activities by increasing inflammatory cytokine production and stimulating NF-κB-mediated signaling. Protein uremic toxins, such as AOPPs, may modify the nonrenal clearance of drugs in patients with CKD by influencing metabolic enzymes.

scholarly journals Inhibitory effect of Sphagnum palustre extract and its bioactive compounds on aromatase activity

2016 ◽  
Vol 11 (3) ◽  
pp. 661
Author(s):  
Hee Jeong Eom ◽  
Yong Joo Park ◽  
Hee Rae Kang ◽  
Ha Ryong Kim ◽  
In Jae Bang ◽  
...  
Keyword(s):  
Video Clip ◽  
Inhibitory Effect ◽  
The Other ◽  
Aromatase Activity ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Aromatase Inhibition ◽  
Concentration Dependent Manner ◽  
Cardiac Pain ◽  
Sphagnum Palustre

<p><em>Sphagnum palustre</em> (a moss) has been traditionally used in Korea for the cure of several diseases such as cardiac pain and stroke. In this research, the inhibitory effect of <em>S. palustre</em> on aromatase (cytochrome P<sub>450</sub> 19, CYP19) activity was studied. [1β-<sup>3</sup>H] androstenedione was used as a substrate and incubated with <em>S. palustre</em> extract and recombinant human CYP19 in the presence of NADPH. <em>S. palustre</em> extract inhibited aromatase in a concentration-dependent manner (IC<sub>50</sub> value: 36.4 ± 8.1 µg/mL). To elucidate the major compounds responsible for the aromatase inhibitory effects of <em>S. palustre</em> extract, nine compounds were isolated from the extract and tested for their inhibition of aromatase activity. Compounds <strong>1</strong>, <strong>6</strong>, and <strong>7</strong> displayed aromatase inhibition, while the inhibition by the other compounds was negligible.</p><p><strong>Video Clip</strong></p><p><a href="https://youtube.com/v/n6xeo3RXJVY">Aromatase enzyme activity:</a> 4 min 16 sec  </p>

Stereoselective Inhibition of Renal Basolateral Human Organic Anion Transporter 3 by Lansoprazole Enantiomers

Pharmacology ◽  
2018 ◽  
Vol 101 (3-4) ◽  
pp. 176-183 ◽  
Author(s):  
Yugo Hamada ◽  
Kenji Ikemura ◽  
Takuya Iwamoto ◽  
Masahiro Okuda
Keyword(s):  
Cultured Cells ◽  
Organic Anion ◽  
Inhibitory Effect ◽  
Organic Anion Transporter ◽  
Racemic Mixture ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Anion Transporter ◽  
Ic50 Value ◽  
Organic Anion Transporter 3

Lansoprazole, a proton pump inhibitor, potently inhibits human organic anion transporter, hOAT3 (SLC22A8). Lansoprazole has an asymmetric atom in its structure and is clinically administered as a racemic mixture of (R)-and (S)-enantiomers. However, little is known about the stereoselective inhibitory potencies of lansoprazole against hOAT3 and its homolog, hOAT1. In the present study, the stereoselective inhibitory effect of lansoprazole was evaluated using hOAT1-and hOAT3-expressing cultured cells. hOAT1 and hOAT3 transported [14C]p-aminohippurate and [3H]estrone-3-sulfate (ES) with Michaelis-Menten constants of 29.8 ± 4.0 and 30.1 ± 9.0 µmol/L respectively. Lansoprazole enantiomers inhibited hOAT1- and hOAT3-mediated transport of each substrate in a concentration-dependent manner. The IC50 value of (S)-lansoprazole against hOAT3-mediated transport of [3H]ES (0.61 ± 0.08 µmol/L) was significantly lower than that of (R)-lansoprazole (1.75 ± 0.31 µmol/L). In contrast, stereoselectivity was not demonstrated for the inhibition of hOAT1. Furthermore, (S)-lansoprazole inhibited hOAT3-mediated transport of pemetrexed and methotrexate (hOAT3 substrates) more strongly than the corresponding (R)-lansoprazole. This study is the first to demonstrate that the stereoselective inhibitory potency of (S)-lansoprazole against hOAT3 is greater than that of (R)-lansoprazole. The present findings provide novel information about the drug interactions associated with lansoprazole.

Pre- and postjunctional effects of some prostanoids in human isolated vas deferens

1991 ◽  
Vol 260 (4) ◽  
pp. R792-R797 ◽  
Author(s):  
F. Holmquist ◽  
H. Hedlund ◽  
K. E. Andersson
Keyword(s):  
Vas Deferens ◽  
Thromboxane A2 ◽  
Electrical Field Stimulation ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Concentration Dependent Manner ◽  
Thromboxane A2 Receptor ◽  
Thromboxane Receptor ◽  
Thromboxane A2 Analogue

The effects of prostaglandin (PG) E1, PGE2, the thromboxane A2 analogue U-44069, and the prostacyclin derivative iloprost were studied on isometric contractions induced by norepinephrine (NE) and by electrical field stimulation of nerves in isolated preparations of the human vas deferens. The effects of these agents on the electrically induced release of 3H from preparations preincubated with [3H]NE were also investigated. PGE1 and PGE2 inhibited the electrically induced contractions concentration dependently. U-44069 augmented the contractions without affecting baseline tension, and in preparations where the contractions had been inhibited by PGE1 or PGE2, U-44069 restored the contractions almost to starting levels. The thromboxane A2-receptor antagonist BM 13505, having no effect or inhibitory effects on electrically induced contractions, abolished the stimulatory effect of U-44069. Contractions induced by exogenous NE were augmented by U-44069, whereas PGE1 and BM 13505 were without effects. The electrically induced release of 3H was inhibited by PGE1 and PGE2 in a concentration-dependent manner, whereas U-44069 and BM 13505 increased the release of 3H. Furthermore, the inhibitory effect of PGE1 on 3H release was partly counteracted by U-44069. Iloprost had no significant effect on electrically induced contractions or on 3H release. These results suggest that, in the human vas deferens, thromboxane A2 augments contractions predominantly through a postjunctional site of action, whereas PGs of the E type have a prejunctional inhibitory effect. In addition, the pre- and post-junctional effect profiles of U-44069 and BM 13505 suggest that there may be more than one thromboxane receptor.

Inhibitory Effects of Garcinia cambogia Extract on CYP2B6 Enzyme Activity

Planta Medica ◽  
2017 ◽  
Vol 83 (11) ◽  
pp. 895-900 ◽  
Author(s):  
Jun Yu ◽  
Min Choi ◽  
Jong Park ◽  
Shaheed Rehman ◽  
Katsunori Nakamura ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Enzyme Activities ◽  
Liver Microsomes ◽  
Cytochrome P450 Enzyme ◽  
Dependent Manner ◽  
Cytochrome P450 Enzymes ◽  
Inhibitory Effects ◽  
Concentration Dependent Manner ◽  
Garcinia Cambogia ◽  
P450 Enzyme

AbstractThis study assessed the inhibitory effects of Garcinia cambogia extract on the cytochrome P450 enzymes in vitro. G. cambogia extract was incubated with cytochrome P450 isozyme-specific substrates in human liver microsomes and recombinant CYP2B6 isozyme, and the formation of the marker metabolites was measured to investigate the inhibitory potential on cytochrome P450 enzyme activities. The results showed that G. cambogia extract has significant inhibitory effects on CYP2B6 activity in a concentration-dependent manner. Furthermore, the inhibition was potentiated following preincubation with NADPH, indicating that G. cambogia extract is a time-dependent inhibitor of CYP2B6. Meanwhile, hydroxycitric acid, the major bioactive ingredient of G. cambogia extract, did not exhibit significant inhibition effects on cytochrome P450 enzyme activities. G. cambogia extract could modulate the pharmacokinetics of CYP2B6 substrate drugs and lead to interactions with those drugs. Therefore, caution may be required with respect to concomitant intake of dietary supplements containing G. cambogia extract with CYP2B6 substrates.

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