Wuzhi Tablet Research Articles

Dosing strategy of tacrolimus when co-administered with Wuzhi tablet in renal transplant recipients.

Tacrolimus (TAC) is a first-line immunosuppressant to prevent allograft rejection. Wuzhi tablet is widely used as a TAC-sparing agent in China that could significantly elevate TAC exposure. However, insufficient data support the dose recommendation of TAC when co-administered with Wuzhi. A total of 305 adult renal transplant patients with 2,541 TAC trough concentrations (C0) were enrolled for population pharmacokinetic (PPK) modeling. CYP3A5 polymorphism was genotyped, and corresponding clinical factors were recorded. Nonlinear mixed-effects modeling and Monte Carlo simulation were used for dose recommendation. PK parameters were calculated based on one-compartment model with first-order absorption and elimination. The estimated total clearance (CL/F) and volume of distribution (Vd/F) of TAC were 23.84 L/h and 1,075.96 L, respectively. Wuzhi, CYP3A5 genotype, hematocrit (HCT), and weight were found to have a significant influence on CL/F. CL/F was significantly lower in the individuals who were CYP3A5 non-expressers and received TAC together with Wuzhi. CYP3A5 genotype (expressers or non-expressers), body weight (40-80 kg), and hematocrit (20 - 40%) were selected as the specific clinical scenarios, and the starting dose of TAC ranged from 1.5 to 4.5 mg when co-administered with Wuzhi. We establish a TAC PPK model comprising Wuzhi as a covariate in renal transplant recipients and recommend an initial dose of TAC when co-administered with Wuzhi, which could provide reference for the individualized regimens of TAC.

Anwulignan Alleviates the Acute Liver Injury Induced by Acetaminophen in Mice

Background Drug-induced liver injury (DILI) is extremely common in clinical practice and needs to be focused. Anwulignan is a unique lignan monomer of Schisandra Sphenanthera Fructus and is used as the main active ingredient of Wuzhi tablet, which is used for liver protection in clinical practice. In this study, an acute liver injury mouse model induced by acetaminophen and paracetamol (APAP) was used to observe its effects. Materials and Methods An acute liver injury mouse model was established by intraperitoneally injecting APAP. Mice were divided into blank control (CON) group, APAP model (MOD) group, Anwulignan CON group, and Anwulignan MOD group. Anwulignan (6 mg/kg) or sodium carboxymethylcellulose (10 mL/kg) was intragastrically given to mice once a day, successively for 14 days. On day 14, 250 mg/kg APAP solution (10 mL/kg) or saline was injected intraperitoneally, and 12 h later, the mice were killed. alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in the serum of mice were tested. The liver index of mice was calculated, and the pathology of liver injury was evaluated by HE staining in mice. The activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) as well as the content of malondialdehyde (MDA) in the liver tissue were tested. The levels of kelch-like ECH-associated protein 1 (Keap-1), nuclear factor erythroid-2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), BCL2 associated X protein (Bax), B-cell lymphoma-2 (Bcl-2), caspase-3 and tumor suppressor protein (P53) mRNAs in the liver tissues of mice were detected by reverse transcription-PCR (RT-PCR), and the expression levels of Keap-1, Nrf2, HO-1, Bax, Bcl-2, caspase-3 and P53 proteins in the liver tissue of mice were detected by Western blot. Results Anwulignan can alleviate the acute liver injury of mice. The down-regulation of the cyclophosphamide (CYP2E1) expression in the liver tissue of mice to reduce the hepatotoxicity of APAP, and the regulation of Nrf2-ARE signaling pathway-related gene expressions to play an antioxidant role and apoptosis-related gene expressions to inhibit the liver cell apoptosis may be involved in the mechanism through which Anwulignan can exert its effect. Conclusion Anwulignan can alleviate the liver injury induced by APAP in mice, and this study may provide evidence for researching and developing some drugs and nutraceuticals used for preventing and treating liver injury.

Prediction of tacrolimus and Wuzhi tablet pharmacokinetic interaction magnitude in renal transplant recipients.

Wuzhi tablets are a dose-sparing agent for tacrolimus (TAC) in China and increase the bioavailability of TAC. The current study aimed to evaluate the pharmacokinetic interaction magnitude of Wuzhi and TAC and explore the potential determinants of this interaction. This study performed a retrospective, self-controlled study of 138 renal transplant recipients who were co-administered TAC and Wuzhi. The trough concentration (C0) of TAC at baseline and 3, 7, 14 and 21 days after Wuzhi co-therapy initiation was measured, and the CYP3A5 polymorphism was genotyped. The corresponding clinical factors were recorded. The ratio of dose-adjusted C0 (C0/D) post- and pre-combination therapy (ΔC0/D) indicates the interaction magnitude. Univariate and multivariate analyses were used to identify determinants and establish the prediction model. ΔC0/D reached a steady state within 14 days. The geometrical mean ΔC0/D was 2.91 (range 1.02-9.49, IQR 2.13-3.80). ΔC0/D was blunted in CYP3A5 expressers (estimated effect: -39.8%, P=.001) and affected by hematocrit (Hct) (+24.0% per 10% increase, P=.005) and baseline C0/D (-31.9% per 1ng·ml-1 ·mg-1 increase, P<.001). The prediction model was ΔC0/D=.319baseline C0/D × 1.398CYP3A5 (expressers=0/non-expressers=1) × 1.024Hct × 1.744, and it explained 28.1% of the variability. Our study is the first attempt to date to give an assessment of the magnitude of pharmacokinetic interaction between TAC and Wuzhi in a cohort of renal transplant recipients, and CYP3A5 genotypes, baseline C0/D and Hct were identified as determinants of this interaction.

Co-administration of Wuzhi tablet (Schisandra sphenanthera extract) alters tacrolimus pharmacokinetics in a dose- and time-dependent manner in rats

Ethnopharmacology relevanceTacrolimus is a well-known potent but expensive immunosuppressant. We previously clarified the herb-drug interaction between tacrolimus and Wuzhi tablet (WZ), a prescribed drug of ethanol extract of Schisandra sphenanthera, and showed the ideal effect of WZ on maintaining therapeutic level of tacrolimus and reducing the total drug expense. However, WZ possesses a biphasic effect on regulating CYP3A (the major metabolizing enzyme of tacrolimus), which could induce the mRNA and protein expression after long-term treatment while transiently inhibit the activity of CYP3A. In clinic, clinicians are confused about the relationship between the blood concentration of tacrolimus and the dose and the duration of pretreatment of WZ. Therefore, the effects of the pretreatment time and the dose of WZ on the pharmacokinetics of tacrolimus is urgently needed to be clarified to better combine the use of WZ and tacrolimus in clinic. Aim of the study and methodThis study aimed to investigate the effects of the pretreatment time and the dose of WZ on the pharmacokinetics of tacrolimus in rats. Results and conclusionsAfter pretreated rats with WZ for 0, 0.5, 2, 6, 12 or 24 h, the area under the curve (AUC) of tacrolimus was 2.27 ± 0.59, 1.87 ± 1.14, 2.86 ± 0.64, 1.62 ± 0.70, 1.54 ± 1.06 and 1.12 ± 0.69-fold of that of the tacrolimus alone group, respectively. The ratio of AUC of tacrolimus to that of the co-administration group with 0, 62.5, 125, 250, 500 or 750 mg/kg of WZ was 1.00: 1.07: 1.44: 2.60: 2.32: 2.42, respectively. These findings suggested that WZ increased tacrolimus AUC in a pretreatment time- and dose-dependent manner. In line with the in vivo findings, WZ extract inhibited CYP3A activity in a pre-treatment time- and concentration-dependent manner in human liver microsomes. In conclusion, the pharmacokinetics of tacrolimus was significantly affected by the pretreatment time and the dose of WZ. Oral pretreatment with WZ for 0–2 h or co-dosing of 250 mg/kg of WZ most significantly increased the blood concentration of tacrolimus. These findings would be helpful for guiding the reasonable use of WZ and tacrolimus in clinic.

Targeted bile acids and gut microbiome profiles reveal the hepato-protective effect of WZ tablet (Schisandra sphenanthera extract) against LCA-induced cholestasis.

Cholestasis is caused by the obstacle of bile formation or secretion and can develop into severe liver diseases. We previously reported the ethanol extract of Schisandra sphenanthera (Wuzhi tablet, WZ) can significantly protect against lithocholic acid (LCA)-induced intrahepatic cholestasis in mice, partially due to the activation of PXR pathway and promotion of liver regeneration. However, the effect of WZ on the bile acids profile and gut microbiome in cholestastic mice remain unknown. In this study, the effect of WZ against LCA-induced liver injury was evaluated and its effect on the bile acids metabolome and gut microbiome profiles in cholestastic mice was further investigated. Targeted metabolomics analysis was performed to examine the change of bile acids in the serum, liver, intestine and feces. The change of intestinal flora were detected by the genomics method. Targeted metabolomics analysis revealed that WZ enhanced the excretion of bile acids from serum and liver to intestine and feces. Genomics analysis of gut microbiome showed that WZ can reverse LCA-induced gut microbiome disorder to the normal level. In conclusion, WZ protects against LCA-induced cholestastic liver injury by reversing abnormal bile acids profiles and alteration of gut microbiome.

Wuzhi Tablet (Schisandra sphenanthera Extract) is a Promising Tacrolimus-Sparing Agent for Renal Transplant Recipients Who are CYP3A5 Expressers: a Two-Phase Prospective Study.

Tacrolimus is a potent but expensive first-line immunosuppressant, thus solutions to reduce tacrolimus consumption while maintain therapeutic level are in urgent need. A two-phase prospective study was conducted to assess the efficacy of an ethanolic extraction preparation of Schisandra sphenanthera (Wuzhi tablet) as a tacrolimus-sparing agent in renal transplant recipients who were high-dose tacrolimus consumers (CYP3A5*1 allele carriers, CYP3A5 expressers). A total of 12 patients were included in the Part I study. After co-administration of Wuzhi tablet, the average individual increment (%) in dose-adjusted C0, Cmax and AUC0-12 hour of tacrolimus were 198.8% (95% CI 149.2, 248.3), 111.0% (95% CI 63.4, 158.6) and 126.1% (95% CI 89.4, 162.8), respectively (P < 0.01), while the average individual reduction (%) in tacrolimus daily dose was 40.9% (95% CI 25.2, 56.6) (P < 0.01). Subsequently, 32 patients were enrolled in a prospective, randomized, controlled study and randomly assigned to receive tacrolimus by CYP3A5 genotype plus Wuzhi tablet co-administration guided dosing (study group) or standard dosing (control group). Besides less tacrolimus dose requirement (P < 0.01), a more accurate tacrolimus initial dose characterized by lower incidence of out-of-range C0 after initial dose (P < 0.01) and fewer dose changes (P < 0.01) was found in the study group. Moreover, no significant differences in acute rejection rate and serum creatinine levels were observed between two groups. Our results show that CYP3A5 genotype plus Wuzhi tablet co-administration guided tacrolimus dosing is a promising therapy for CYP3A5 expressers in the early post-transplant stage, while further study with a larger sample size is required to prove these findings.

Schisandra sphenanthera extract (Wuzhi Tablet) protects against chronic-binge and acute alcohol-induced liver injury by regulating the NRF2-ARE pathway in mice

Alcohol abuse leads to alcoholic liver disease and no effective therapy is currently available. Wuzhi Tablet (WZ), a preparation of extract from Schisandra sphenanthera that is a traditional hepato-protective herb, exerted a significant protective effect against acetaminophen-induced liver injury in our recent studies, but whether WZ can alleviate alcohol-induced toxicity remains unclear. This study aimed to investigate the contribution of WZ to alcohol-induced liver injury by using chronic-binge and acute models of alcohol feeding. The activities of ALT and AST in serum were assessed as well as the level of GSH and the activity of SOD in the liver. The expression of CYP2E1 and proteins in the NRF2-ARE signaling pathway including NRF2, GCLC, GCLM, HO-1 were measured, and the effect of WZ on NRF2 transcriptional activity was determined. We found that both models resulted in liver steatosis accompanied by increased transaminase activities, but that liver injury was significantly attenuated by WZ. WZ administration also inhibited CYP2E1 expression induced by alcohol, and elevated the level of GSH and the activity of SOD in the liver. Moreover, the NRF2-ARE signaling pathway was activated by WZ and the target genes were all upregulated. Furthermore, WZ significantly activated NRF2 transcriptional activity. Collectively, our study demonstrates that WZ protected against alcohol-induced liver injury by reducing oxidative stress and improving antioxidant defense, possibly by activating the NRF2-ARE pathway.

Metabolic mapping of Schisandra sphenanthera extract and its active lignans using a metabolomic approach based on ultra high performance liquid chromatography with high-resolution mass spectrometry.

Schisandra sphenanthera, the dried ripe fruit of Schisandra sphenanthera Rehd. et Wils, is widely used as a restorative, tonic and nutrition in many countries. Wuzhi tablet, an ethanol extract preparation of Schisandra sphenanthera, is a well-known herbal medicine widely used in China. Our previous studies show that Wuzhi tablet and its active lignans significantly protect liver injury. However, its metabolic profile remains unknown in vivo and in vitro. In this study, ultra high performance liquid chromatography coupled with electrospray ionization high-resolution mass spectrometry based metabolomics was employed to decipher the metabolic map of Wuzhi tablet and its active lignans. Serum (2 h) and urine (24 h) samples after a 700 mg/kg single oral dose of Wuzhi tablet, and mice liver microsome samples after incubation with its active lignans were collected and analyzed. The data were further analyzed using metabolomics and metabolite identification software. In total, 33 metabolites in vivo and 34 metabolites in vitro were identified, and six among them were new metabolites. The major metabolic reactions encompassed demethylation, hydroxylation, dehydrogenation, and epoxidation. Taken together, in vitro and in vivo studies revealed the metabolic profile of Wuzhi tablet and its active lignans and demethylation and hydroxylation were their major metabolic pathways.

Schisandra sphenanthera Extract Facilitates Liver Regeneration after Partial Hepatectomy in Mice.

Liver regeneration after surgical liver resection is crucial for the restoration of liver mass and the recovery of liver function.Schisandra sphenanthera extract (Wuzhi tablet, WZ) is a preparation of an extract from the dried ripe fruit of Schisandra sphenanthera Rehd. et Wils, a traditional hepatoprotective herb. Previously, we found that WZ could induce liver regeneration-related genes against acetaminophen-induced liver injury. However, whether WZ can directly facilitate liver regeneration after liver resection remains unknown. We investigated whether WZ has potential in promoting liver regeneration after a partial hepatectomy (PHX) in mice. Remnant livers were collected 1, 1.5, 2, 3, 5, 7, and 10 days after PHX. Hepatocyte proliferation was assessed using the Ki-67 labeling index. Western blot analysis was performed on proteins known to be involved in liver regeneration. The results demonstrated that WZ significantly increased the liver-to-body weight ratio of mice after PHX but had no effect on that of mice after a sham operation. Additionally, the peak hepatocyte proliferation was observed at 1.5 days in PHX/WZ-treated mice but at 2 days in PHX/saline-treated mice, as evidenced by the Ki-67 positive ratio. Furthermore, WZ significantly increased the protein expression of ligand-induced phosphorylation of epidermal growth factor receptor and up-regulated cyclin D1, cyclin D-dependent kinase 4, phosphorylated retinoblastoma, and proliferating cell nuclear antigen protein expression and down-regulated the expression of cell cycle inhibitors p21 and p27 in the regenerative process after PHX. These results demonstrate that WZ significantly facilitates hepatocyte proliferation and liver regeneration after PHX.

Hepatoprotective Effects of Schisandra sphenanthera Extract against Lithocholic Acid-Induced Cholestasis in Male Mice Are Associated with Activation of the Pregnane X Receptor Pathway and Promotion of Liver Regeneration.

We previously reported that the ethanol extract of Schisandra sphenanthera [Wuzhi (WZ) tablet] significantly protects against acetaminophen-induced hepatoxicity. However, whether WZ exerts a protective effect against cholestasis remains unclear. In this study, the protective effect of WZ on lithocholic acid (LCA)-induced intrahepatic cholestasis in mice was characterized and the involved mechanisms were investigated. WZ pretreatment (350 mg/kg) with LCA significantly reversed liver necrosis and decreased serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activity. More importantly, serum total bile acids and total bilirubin were also remarkably reduced. Quantitative reverse-transcription polymerase chain reaction and Western blot analysis showed that hepatic expression of pregnane X receptor (PXR) target genes such as CYP3A11 and UDP-glucuronosyltransferase (UGT) 1A1 were significantly increased by WZ treatment. Luciferase assays performed in LS174T cells illustrated that WZ extract and its six bioactive lignans could all activate human PXR. In addition, WZ treatment significantly promoted liver regeneration via inhibition of p53/p21 to induce cell proliferation-associated proteins such as cyclin D1 and proliferating cell nuclear antigen. In conclusion, WZ has a protective effect against LCA-induced intrahepatic cholestasis, partially owing to activation of the PXR pathway and promotion of liver regeneration.

Protective effect of Wuzhi tablet (Schisandra sphenanthera extract) against cisplatin-induced nephrotoxicity via Nrf2-mediated defense response

Cisplatin is a potent anti-cancer agent for various types of tumors. However, the clinical use of cisplatin is often limited by its nephrotoxicity. This study reports that WZ tablet (WZ, a preparation of an ethanol extract of Schisandra sphenanthera) mitigates cisplatin-induced toxicity in renal epithelial HK-2 cells and in mice. Pretreatment of HK-2 cells with WZ ameliorated cisplatin-induced cytotoxicity caused by oxidative stress, as was demonstrated by reductions in the levels of reactive oxygen species (ROS) and increased levels of glutathione (GSH). WZ facilitated the nuclear accumulation of the transcription factor NF-E2-related factor 2 (Nrf2) and the subsequent expression of its target genes such as NAD(P)H:quinine oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1) and glutamate cysteine ligase (GCL). Protective effects of WZ on cisplatin-induced nephrotoxicity were also observed in mice. WZ attenuated cisplatin-induced renal dysfunction, structural damage and oxidative stress. The nuclear accumulation of Nrf2 and its target genes were increased by WZ treatment. Taken together, these findings demonstrated WZ have a protective effect against cisplatin-induced nephrotoxicity by activation of the Nrf2 mediated defense response, which is of significant importance for therapeutic intervention in cisplatin induced renal injury.

Therapeutic Efficacy of Wuzhi Tablet (Schisandra sphenanthera Extract) on Acetaminophen-Induced Hepatotoxicity through a Mechanism Distinct from N-Acetylcysteine

Acetaminophen (APAP) hepatotoxicity is the most common cause of drug-induced liver injury and N-acetylcysteine (NAC) is the primary antidote of APAP poisoning. Wuzhi tablet (WZ), the active constituents well identified and quantified, is a preparation of an ethanol extract of Schisandra sphenanthera and exerts a protective effect toward APAP-induced hepatotoxicity in mice. However, the clinical use of WZ to rescue APAP-induced acute liver injury and the mechanisms involved in the therapeutic effect of WZ remain unclear. Therefore, the effect of WZ on APAP hepatotoxicity was compared with NAC in mice, and molecular pathways contributing to its therapeutic action were investigated. Administration of WZ 4 hours after APAP treatment significantly attenuated APAP hepatotoxicity and exerted much better therapeutic effect than NAC, as revealed by morphologic, histologic, and biochemical assessments. Both WZ and NAC prevented APAP-induced c-Jun N-terminal protein kinase activation and mitochondrial glutathione depletion in livers. The protein expression of nuclear factor erythroid 2-related factor 2 target genes including Gclc, Gclm, Ho-1, and Nqo1 was increased by WZ administration. Furthermore, p53 and p21 levels were upregulated upon APAP exposure, which were completely reversed by postdosing of WZ 4 hours after APAP treatment over 48 hours. In comparison with NAC, WZ significantly increased the expression of cyclin D1, cyclin D-dependent kinase 4, proliferating cell nuclear antigen, and augmenter of liver regeneration in APAP-injured livers. This study demonstrated that WZ possessed a therapeutic efficacy against APAP-induced liver injury by inhibiting oxidative stress and stimulating a regenerative response after liver injury. Thus WZ may represent a new therapy for APAP-induced acute liver injury.

Wuzhi tablet (Schisandra Sphenanthera extract) protects against acetaminophen-induced hepatotoxicity by inhibition of CYP-mediated bioactivation and regulation of NRF2-ARE and p53/p21 pathways.

Schisandra sphenanthera is widely used as a tonic and restorative in many countries to enhance the function of liver and other organs. Wuzhi tablet (WZ) is a preparation of an ethanol extract of Schisandra sphenanthera. Our previous study demonstrated that WZ exerted a protective effect toward acetaminophen (APAP)-induced hepatotoxicity. However, the molecular mechanisms of this protection remain unclear. This study aimed to determine what molecular pathways contributed to the hepatoprotective effects of WZ against APAP toxicity. Administration of WZ 3 days before APAP treatment significantly attenuated APAP hepatotoxicity in a dose-dependent manner and reduced APAP-induced JNK activation. Treatment with WZ resulted in potent inhibition of CYP2E1, CYP3A11, and CYP1A2 activities and then caused significant inhibition of the formation of the oxidized APAP metabolite N-acetyl-p-benzoquinone imine-reduced glutathione. The expression of NRF2 was increased after APAP and/or WZ treatment, whereas KEAP1 levels were decreased. The protein expression of NRF2 target genes including Gclc, Gclm, Ho-1, and Nqo1 was significantly increased by WZ treatment. Furthermore, APAP increased the levels of p53 and its downstream gene p21 to trigger cell cycle arrest and apoptosis, whereas WZ pretreatment could inhibit p53/p21 signaling to induce cell proliferation-associated proteins including cyclin D1, CDK4, PCNA, and ALR to promote hepatocyte proliferation. This study demonstrated that WZ prevented APAP-induced liver injury by inhibition of cytochrome P450-mediated APAP bioactivation, activation of the NRF2-antioxidant response element pathway to induce detoxification and antioxidation, and regulation of the p53, p21, cyclin D1, CDK4, PCNA, and ALR to facilitate liver regeneration after APAP-induced liver injury.

Effect of Tacrolimus on the pharmacokinetics of bioactive lignans of Wuzhi tablet (Schisandra sphenanthera extract) and the potential roles of CYP3A and P-gp

We recently reported that Wuzhi tablet (WZ), a preparation of the ethanol extract of Wuweizi (Schisandra sphenanthera), had significant effects on blood concentrations of Tacrolimus (FK506) in renal transplant recipients and rats. The active lignans in WZ are schisandrin A, schisandrin B, schisandrin C, schisandrol A, schisandrol B, schisantherin A, and schisantherin B. Until now, whether the pharmacokinetics of these lignans in WZ would be affected by FK506 remained unknown. Therefore, this study aimed to investigate whether and how FK506 affected pharmacokinetics of lignans in WZ in rats and the potential roles of CYP3A and P-gp. After a single oral co-administration of FK506 and WZ, the blood concentration of lignans in WZ was decreased by FK506; furthermore, the AUC of schisantherin A, schisandrin A, schisandrol A and schisandrol B was only 64.5%, 47.2%, 55.1% and 57.4% of that of WZ alone group, respectively. Transport study in Caco-2 cells showed that these lignans were not substrates of P-gp, suggesting decreased blood concentration of lignans by FK506 was not via P-gp pathway. Metabolism study in the human recombinant CYP 3A showed that these lignans had higher affinity to CYP3A than that of FK506, and thus had a stronger CYP3A-mediated metabolism. It was concluded that the blood concentrations of these lignans were decreased and their CYP3A-mediated metabolisms were increased in the presence of FK506 since these lignans had higher affinity to CYP3A.

In Vivo to In Vitro Effects of Six Bioactive Lignans of Wuzhi Tablet (Schisandra Sphenanthera Extract) on the CYP3A/P-glycoprotein–Mediated Absorption and Metabolism of Tacrolimus

We recently reported that Wuzhi tablet (WZ; Schisandra sphenanthera extract) can inhibit P-glycoprotein (P-gp)-mediated efflux and CYP3A-mediated metabolism of tacrolimus (FK506) and thus increase the blood concentrations of FK506. Major active lignans of WZ include schisandrin A, schisandrin B, schisandrin C, schisandrol A, schisandrol B, and schisantherin A. Whether and how these six lignans affect the pharmacokinetics of FK506 remains unclear. Therefore, this study aimed to investigate the effects of these lignans on the first-pass absorption and metabolism of FK506 and the involved mechanisms in vitro and in vivo. The results showed that whole-blood concentrations of FK506 were increased to different degrees following coadministration of the six lignans, respectively. Schisandrol B showed the strongest effect on the increase of the area under the concentration-time curve, the oral bioavailability, the gut processes affecting availability, and the hepatic availability of FK506. The reduction of intestinal first-pass effect contributed most to the increase in oral bioavailability of FK506 when coadministered with schisandrol B. In vitro transport experiment showed that schisandrin A, schisandrin B, and schisandrol B inhibited P-gp-mediated efflux of FK506. In vitro metabolism study showed that the inhibitory effect of these six lignans on FK506 metabolism was dose-dependent. In conclusion, the exposure of FK506 in rats was increased when coadministered with these lignans, and schisandrol B showed the strongest effect. Lignans of WZ inhibited P-gp-mediated efflux and CYP3A-mediated metabolism of FK506, and the reduction of intestinal first-pass affected by the lignans was the major cause of the increased FK506 oral bioavailability.

Targeted Metabolomics of Serum Acylcarnitines Evaluates Hepatoprotective Effect of Wuzhi Tablet (Schisandra sphenantheraExtract) against Acute Acetaminophen Toxicity

Possible prevention and therapeutic intervention strategies to counteract acetaminophen (APAP) hepatotoxicity would be of great value. Wuzhi tablet (WZ, extract of Schisandrae sphenanthera) possesses hepatoprotective effects against hepatitis and the hepatic dysfunction induced by various chemical hepatotoxins. In this study, the protective effect of WZ on APAP-induced hepatic injury was evaluated and targeted metabolomics by LC-MS-based metabolomics was used to examine whether WZ influences hepatic metabolism. The results demonstrated significant hepatoprotection of WZ against APAP-induced liver injury; pretreatment with WZ prior to APAP administration blocks the increase in serum palmitoylcarnitine and oleoylcarnitine and thus restores the APAP-impaired fatty acid β-oxidation to normal levels. These studies further revealed a significant and prolonged upregulation of the PPARα target genes Cpt1 and Acot1 by WZ mainly contributing to the maintenance of normal fatty acid metabolism and thus potentially contributing to the hepatic protection of WZ against APAP-induced hepatic toxicity. Taken together, the current study provides new insights into understanding the hepatoprotective effect of WZ against APAP-induced liver toxicity.

Effect of long-term co-administration of Wuzhi tablet (Schisandra sphenanthera extract) and prednisone on the pharmacokinetics of tacrolimus

Tacrolimus (TAC) is an immunosuppressant that has been widely used alone or in combination with prednisone (PRED) to prevent acute rejection after organ transplantation. Wuzhi tablet (WZ, Schisandra sphenanthera extract) is often prescribed with TAC to prevent drug-induced hepatitis. We recently reported that WZ could significantly increase TAC blood exposure by inhibiting P-gp-mediated efflux and CYP3A-mediated metabolism of TAC. PRED is also a substrate of P-gp and is a weak inducer of CYP3A, and drug-drug interactions within this combination therapy might occur. Therefore, the purpose of this study was to investigate the effect of long-term treatment of WZ and PRED on the pharmacokinetics of TAC in rats. After 14 days of co-administration of WZ and PRED, the AUC0–24h of oral TAC was increased (from 59.6±37.3 to 95.3±39.4 ngh/ml, p=0.18) and the clearance was decreased (from 38.4±28.4 to 17.7±6.4l/h/kg, p=0.15). When only co-administered with WZ, AUC0–24h of TAC was demonstrated a significantly increase (from 59.6±37.3 to 135.9±34.8 ngh/ml, p<0.05). The concomitant administration of PRED resulted in a reduction in the systemic exposure of TAC and an increase in its clearance, though neither was statistically significant. Thus, our study suggested that the presence of WZ and PRED still could increase the systemic exposure of TAC in rats. The drug–drug interactions among this combination therapy should still be taken into consideration in clinical practice.

Effect of Wuzhi Tablet (Schisandra sphenanthera extract) on the Pharmacokinetics of Cyclosporin A in Rats

In our previous reports, Wuzhi tablet (an herbal preparation of ethanol extract of Wuweizi (Schisandra sphenanthera)) can significantly increase the blood concentration of tacrolimus and paclitaxel in rats by inhibiting the CYP3A-mediated metabolism and the P-gp-mediated efflux. Cyclosporin A (CsA), a well-known immunosuppressant agent, is also a substrate of CYP3A and P-gp. Therefore, this study aimed to investigate whether and how WZ affects pharmacokinetics of CsA in rats. The AUC0-48 h and Cmax of CsA were increased by 40.1% and 13.1%, respectively, with a single oral co-administration of WZ and high dose of CsA (37.8 mg/kg). Interestingly, after a single oral co-administration of WZ and low dose of CsA (1.89 mg/kg), the AUC0-36 h and Cmax of CsA were dramatically increased by 293.1% (from 1103.2 ± 293.0 to 4336.5 ± 1728.3 ng.h/mL; p < 0.05) and 84.1% (from 208.5 ± 67.9 to 383.1 ± 92.5 ng/mL; p < 0.05), respectively. The CL/F was decreased from 1.7 L/h/kg to 0.5 L/h/kg. Thus, the effect of WZ on high dose of CsA was not significant, but pharmacokinetic parameters of CsA at low dose were significantly influenced by co-administration of WZ. The herb-drug interaction should be taken into consideration at this situation.

Effect of Wuzhi Tablet (Schisandra sphenanthera extract) on the Pharmacokinetics of Paclitaxel in Rats

Wuzhi tablet (WZ, registration no. in China: Z20025766) is a preparation of an ethanol herb extract of Wuweizi (Schisandra sphenanthera) containing 7.5 mg Schisantherin A per tablet. It was reported recently that WZ could significantly increase the blood concentrations of tacrolimus, which might be due to the inhibitory effect of WZ and its ingredients on P-gp and/or CYP450 activity. Paclitaxel is a substrate of the efflux transporter P-gp, and is mainly metabolized by CYP450 enzymes in the liver. Therefore, the purpose of this study was to investigate whether and how WZ affects the pharmacokinetics of paclitaxel in rats. After pretreatment with WZ, there were significant increases in the AUC(0-24h) of oral paclitaxel (from 280.8 ± 97.3 to 543.5 ± 115.2 h ng/mL; p < 0.05) and C(max) (from 44.6 ± 16.4 to 86.8 ± 16.1 ng/mL; p < 0.05). The pharmacokinetic data for i.v. paclitaxel with WZ showed a relatively small (when compared against oral paclitaxel) but still significant increase in AUC(0-24h) (from 163.6 ± 22.1 to 212.7 ± 17.7 h ng/mL; p < 0.05) and a decrease in clearance (from 3.2 ± 0.6 to 2.2 ± 0.3 L/h/kg; p < 0.05). Thus, the presence of WZ improved the systemic exposure of paclitaxel in rats. The herb-drug interaction between WZ and paclitaxel should be taken into consideration in clinical use.

Mechanistic understanding of the different effects of Wuzhi Tablet ( Schisandra sphenanthera extract) on the absorption and first-pass intestinal and hepatic metabolism of Tacrolimus (FK506)

We recently reported that the blood concentrations of Tacrolimus (FK506) in rats were markedly increased following the intake of a Chinese herbal preparation, Wuzhi Tablet (WZ, Schisandra sphenanthera extract). In order to identify the underlying mechanisms of the increase in FK506 level, we investigated the effects of WZ on the absorption and first-pass intestinal and hepatic metabolism of FK506 in vitro and in vivo. When co-administered with WZ, the AUC 0–∞ value after oral FK506 dosing was increased by 2.1 fold, the oral bioavailability ( F oral) was increased from 5.4% to 13.2% ( p = 0.0002), and the ( F abs × F G) was 111.4% ( p < 0.01), much greater than that when FK506 was given alone. However, the F H was only 21.2% greater than that when FK506 was given alone, which indicates that the reduction of intestinal first-pass effect was the major cause of the increased FK506 oral bioavailability when co-administered with WZ. In the Caco-2 cell transport study, the transport ratio of FK506 with WZ extract was significantly lower than that of FK506 alone, which suggested WZ extract inhibited P-gp-mediated efflux of FK506. Furthermore, 100 μM of WZ extract almost completely inhibited FK506 metabolism in rat and human liver microsomes, indicating WZ extract potently inhibited the CYP3A-mediated metabolism of FK506. In conclusion, WZ inhibited P-gp-mediated efflux and CYP3A-mediated metabolism of FK506, and the reduction of intestinal first-pass effect by WZ was the major cause of the increased FK506 oral bioavailability.