Screening and verification of CYP3A4 inhibitors from Bushen-Yizhi formula to enhance the bioavailability of osthole in rat plasma.

ETHNOPHARMACOLOGICAL RELEVANCE: With the features of multiple-components and targets as well as multifunction, traditional Chinese medicine (TCM) has been widely used in the prevention and treatment of various diseases for a long time. During the application of TCM, the researches about bioavailability enhancement of the bioactive constituents in formula are flourishing. Bushen-Yizhi formula (BSYZ), a TCM prescription with osthole (OST) as one of the main bioactive ingredients, have been widely used to treat kidney deficiency, mental retardation and Alzheimer's disease. However, the underlying biological mechanism and compound-enzyme interaction mediated bioavailability enhancement of OST are still not clearly illuminated. AIM OF THE STUDY: The aim of this study is to explore the material basis and molecular mechanism from BSYZ in the bioavailability enhancement of OST. Screening the potential CYP3A4 inhibitors using theoretical prediction and then verifying them in vitro, and pharmacokinetics study of OST in rat plasma under co-administrated of screened CYP3A4 inhibitors and BSYZ were also scarcely reported. MATERIALS AND METHODS: Screening of CYP3A4 inhibitors from BSYZ was performed with molecular docking simulation from systems pharmacology database. The screened compounds were verified by using P450-Glo Screening Systems. A multiple reaction monitoring (MRM) mass spectrometry method was established for OST quantification. Male Sprague-Dawley rats divided into four groups and six rats in each group were employed in the pharmacokinetics study of OST. The administrated conditions were group I, OST (20 mg/kg); group II, BSYZ (containing OST 1 mg/mL, at the dose of 20 mg/kg OST in BSYZ); group III, co-administration of ketoconazole (Ket, 75 mg/kg) and OST (20 mg/kg); group IV, co-administration of CYP3A4 inhibitor (10 mg/kg) and OST (20 mg/kg). They were determined by using HPLC-MS/MS (MRM) and statistical analysis was performed using student's t-test with p < 0.05 as the level of significance. RESULTS: 21 potential CYP3A4 inhibitors were screened from BSYZ compounds library. From the results of verification in vitro, we found 4 compounds with better CYP3A4 inhibition efficiency including Oleic acid, 1,2,3,4,6-O-Pentagalloylglucose, Rutin, and Schisantherin B. Under further verification, Schisantherin B exhibited the best inhibitory effect on CYP3A4 (IC50 = 0.339 µM), and even better than the clinically used drug (Ket) at the concentration of 5 µM. In the study of pharmacokinetics, the area under the curve (AUC, ng/L*h) of OST after oral administration of BSYZ, Ket and Schisantherin B (2196.23 ± 581.33, 462.90 ± 92.30 and 1053.03 ± 263.62, respectively) were significantly higher than that of pure OST treatment (227.89 ± 107.90, p < 0.01). CONCLUSIONS: Schisantherin B, a profoundly effective CYP3A4 inhibitor screened from BSYZ antagonized the metabolism of CYP3A4 on OST via activity inhibition, therefore significantly enhanced the bioavailability of OST in rat plasma. The results of this study will be helpful to explain the rationality of the compatibility in TCM formula, and also to develop new TCM formula with more reasonable drug compatibility.

The anti-ovarian cancer effect of RPV modified paclitaxel plus schisandra B liposomes in SK-OV-3 cells and tumor-bearing mice.

AIMS: Due to poor targeting ability of anti-tumor drugs and self-adaptation of tumors, the chemotherapy of ovarian cancer is still poorly effective. In recent years, the treatment of tumor with nano-targeted agents has become a potential research focus. In this study, a new type of short cell-penetrating peptide RPV-modified paclitaxel plus schisandrin B liposomes were constructed to disrupt VM channels, angiogenesis, proliferation and migration for the treatment of ovarian cancer. MATERIALS AND METHODS: In this study, clone assay, TUNEL, Transwell, wound-healing, CAM and mimics assay were used to detect the effects of RPV-modified liposomes on ovarian cancer SK-OV-3 cells before and after treatment. HE-staining, immunofluorescence and ELISA were used to further detect the expression of tumor-related proteins. KEY FINDINGS: RPV-modified paclitaxel plus schisandrin B liposomes can inhibit angiogenesis, VM channel formation, invasion and proliferation of ovarian SK-OV-3 cells. In vitro and in vivo studies showed that tumor-related protein expression was down-regulated. Modification of RPV can prolong the retention time of liposome in vivo and accumulate in the tumor site, increasing the anti-tumor efficacy. SIGNIFICANCE: The RPV-modified paclitaxel plus schisandrin B liposomes have good anti-tumor effect, thus may provide a new avenue for the treatment of ovarian cancer.

Lefamulin efficacy and safety in a pooled phase 3 clinical trial population with community-acquired bacterial pneumonia and common clinical comorbidities.

BACKGROUND: Lefamulin, a first-in-class pleuromutilin antibiotic approved for intravenous and oral use in adults with community-acquired bacterial pneumonia (CABP), was noninferior to moxifloxacin in the Lefamulin Evaluation Against Pneumonia (LEAP) 1 intravenous-to-oral switch study and the LEAP 2 oral-only study. Using pooled LEAP 1/2 data, we examined lefamulin efficacy/safety overall and within subgroups of patients presenting with comorbidities typical in CABP management. METHODS: In LEAP 1, adults with CABP were randomized to receive intravenous lefamulin (150 mg every 12 h) for 5‒7 days or moxifloxacin (400 mg every 24 h) for 7 days, with optional intravenous-to-oral switch if predefined improvement criteria were met. In LEAP 2, adults with CABP were randomized to receive oral lefamulin (600 mg every 12 h) for 5 days or moxifloxacin (400 mg every 24 h) for 7 days. Both studies assessed early clinical response (ECR) at 96 ± 24 h after first study drug dose and investigator assessment of clinical response (IACR) at test-of-cure (5‒10 days after last dose). Pooled analyses of the overall population used a 10% noninferiority margin. RESULTS: Lefamulin (n = 646) was noninferior to moxifloxacin (n = 643) for ECR (89.3% vs 90.5%, respectively; difference - 1.1%; 95% CI - 4.4 to 2.2); IACR success rates at test-of-cure were similarly high (≥ 85.0%). High efficacy with both lefamulin and moxifloxacin was also demonstrated across all well-represented patient subgroups, including those with advanced age, diabetes mellitus, a history of cardiovascular diseases (e.g., hypertension, congestive heart failure, or arrhythmia) or chronic lung diseases (e.g., asthma or chronic obstructive pulmonary disease), elevated liver enzymes, or mild-to-moderate renal dysfunction. No new safety signals were identified. CONCLUSIONS: Lefamulin may provide a valuable intravenous/oral monotherapy alternative to fluoroquinolones or macrolides for empiric treatment of patients with CABP, including cases of patients at risk for poor outcomes due to age or various comorbidities. TRIAL REGISTRATION: ClinicalTrials.gov LEAP 1 (NCT02559310; Registration Date: 24/09/2015) and LEAP 2 (NCT02813694; Registration Date: 27/06/2016).

Pharmacokinetics and safety of lefamulin after single intravenous dose administration in subjects with impaired-hepatic function.

STUDY OBJECTIVE: Lefamulin is a novel pleuromutilin recently approved by the FDA for the treatment of community-acquired bacterial pneumonia. Given that, lefamulin is primarily metabolized by CYP450 Phase-1 reactions, this study evaluated the pharmacokinetics of IV lefamulin in subjects with various degrees of hepatic impairment as compared with matched healthy subjects. DESIGN: Open-label, Phase-1 clinical pharmacokinetic study. SETTING: Research Study Center. PATIENTS: Twenty-seven subjects; comprised of 11 individuals with normal hepatic function and eight each with moderate or severe hepatic impairment were included, as classified by Child-Pugh scores. MEASUREMENTS AND MAIN RESULTS: Subjects were administered a single dose of IV lefamulin 150 mg over 1 h. Plasma was collected for 48 h and analyzed for lefamulin and its major metabolite, BC-8041, concentrations in addition to assessing lefamulin plasma protein binding. Pharmacokinetics were evaluated by noncompartmental analysis. Pharmacokinetic parameters were compared using least square geometric mean ratios. Lefamulin was well tolerated in all hepatic function groups. Statistical analyses revealed reductions in Cmax and increases in renal clearance for Moderate and Severe groups, as well as, the increased volume of distribution for the Severe group. Lefamulin plasma AUC mean (SD) was similar across groups at 7615 (1554), 8233 (2286), and 8938 (1640) h.ng/mL for Normal, Moderate, and Severe groups, respectively, despite decreased clearance observed primarily during terminal elimination phases. Decreased plasma-protein binding was seen in hepatically-impaired versus normal subjects. CONCLUSION: Lefamulin was generally well tolerated. Differences in lefamulin and BC-8041 pharmacokinetics were small, relative to the overall variability, and any changes appear to be compensated by increases in renal clearance and decreased protein binding.

Pharmacokinetics and safety of lefamulin after single intravenous dose administration in subjects with impaired renal function and those requiring hemodialysis.

STUDY OBJECTIVE: Lefamulin is a novel IV and oral pleuromutilin recently approved for the treatment of community-acquired bacterial pneumonia (CABP). Given that renal comorbidities are common in patients admitted for CABP, understanding the pharmacokinetics of lefamulin in the face of severe renal impairment, including those requiring hemodialysis, is needed. DESIGN: Open-label, Phase-1 pharmacokinetic study. SETTING: Research Study Center. PATIENTS: Twenty-three matched subjects were included, seven with "Normal" renal function (creatinine clearance >90 ml/min), eight with "Severe" renal impairment (glomerular filtration rate <30 ml/min/1.73 m2 ), and eight subjects requiring hemodialysis. MEASUREMENTS AND MAIN RESULTS: Subjects were administered a single dose of lefamulin IV 150 mg as a 1-h infusion. Subjects in the hemodialysis group started hemodialysis within 1 h after lefamulin infusion (On dialysis), as well as, on a non-dialysis day (Off dialysis). Plasma, urine, and dialysate fluid were collected for 36 h and analyzed for lefamulin and its major metabolite, BC-8041. Lefamulin was primarily excreted non-renally across groups. Statistical analyses revealed lefamulin and BC-8041 pharmacokinetics were similar between Normal and Severe groups, except for renal clearance, which decreased in Severe subjects (mean 1.3 L/h Normal vs. 0.4 L/h Severe). Likewise, lefamulin pharmacokinetics during on and off dialysis were unchanged, with lefamulin not measurably filtered in dialysate fluid. Two, three, and three subjects reported drug-related treatment-emergent adverse events (TEAE) in Normal, Severe, and Hemodialysis groups, respectively. All TEAEs were mild, except one (infusion-site reaction) that was classified as moderate. CONCLUSION: No dosage adjustment is required for patients with renal impairment, and lefamulin can be administered without regard to hemodialysis timing.

Lefamulin: A Novel Oral and Intravenous Pleuromutilin for the Treatment of Community-Acquired Bacterial Pneumonia.

Lefamulin is a novel oral and intravenous (IV) pleuromutilin developed as a twice-daily treatment for community-acquired bacterial pneumonia (CABP). It is a semi-synthetic pleuromutilin with a chemical structure that contains a tricyclic core of five-, six-, and eight-membered rings and a 2-(4-amino-2-hydroxycyclohexyl)sulfanylacetate side chain extending from C14 of the tricyclic core. Lefamulin inhibits bacterial protein synthesis by binding to the 50S bacterial ribosomal subunit in the peptidyl transferase center (PTC). The pleuromutilin tricyclic core binds to a pocket close to the A site, while the C14 side chain extends to the P site causing a tightening of the rotational movement in the binding pocket referred to as an induced-fit mechanism. Lefamulin displays broad-spectrum antibacterial activity against Gram-positive and Gram-negative aerobic and anaerobic bacteria as well as against atypical bacteria that commonly cause CABP. Pleuromutilin antibiotics exhibit low rates of resistance development and lack cross-resistance to other antimicrobial classes due to their unique mechanism of action. However, pleuromutilin activity is affected by mutations in 23S rRNA, 50S ribosomal subunit proteins rplC and rplD, ATP-binding cassette (ABC)-F transporter proteins such as vga(A), and the methyltransferase cfr. The pharmacokinetic properties of lefamulin include: volume of distribution (Vd) ranging from 82.9 to 202.8 L, total clearance (CLT) of 19.5 to 21.4 L/h, and terminal elimination half-life (t1/2) of 6.9-13.2 h; protein binding of lefamulin is high and non-linear. The oral bioavailability of lefamulin has been estimated as 24% in fasted subjects and 19% in fed subjects. A single oral dose of lefamulin 600 mg administered in fasted patients achieved a maximum plasma concentration (Cmax) of 1.2-1.5 mg/L with a time of maximum concentration (Tmax) ranging from 0.8 to 1.8 h, and an area under the plasma concentration-time curve from 0 to infinity (AUC0-∞) of 8.5-8.8 mg h/L. The pharmacodynamic parameter predictive of lefamulin efficacy is the free plasma area under the concentration-time curve divided by the minimum inhibitory concentration (fAUC24h/MIC). Lefamulin efficacy has been demonstrated using various animal models including neutropenic murine thigh infection, pneumonia, lung infection, and bacteremia. Lefamulin clinical safety and efficacy was investigated through a Phase II clinical trial of acute bacterial skin and skin structure infection (ABSSSI), as well as two Phase III clinical trials of CABP. The Phase III trials, LEAP 1 and LEAP 2 established non-inferiority of lefamulin to moxifloxacin in both oral and IV formulations in the treatment of CABP. The United States Food and Drug Administration (FDA), European Medicines Agency (EMA), and Health Canada have each approved lefamulin for the treatment of CABP. A Phase II clinical trial has been completed for the treatment of ABSSSI, while the pediatric program is in Phase I. The most common adverse effects of lefamulin include mild-to-moderate gastrointestinal-related events such as nausea and diarrhea. Lefamulin represents a safe and effective option for treating CABP in cases of antimicrobial resistance to first-line therapies, clinical failure, or intolerance/adverse effects to currently used agents. Clinical experience and ongoing clinical investigation will allow clinicians and antimicrobial stewardship programs to optimally use lefamulin in the treatment of CABP.

Mechanisms dissection of the combination GRS derived from ShengMai preparations for the treatment of myocardial ischemia/reperfusion injury.

ETHNOPHARMACOLOGICAL RELEVANCE: Recently, a new drug combination GRS comprising ginsenoside Rb1 (G-Rb1), ruscogenin (R-Rus) and schisandrin (S-SA) was screened based on ShengMai preparations, which exhibited a prominent cardioprotective effects against myocardial ischemia/reperfusion (MI/R) injury. AIM OF THE STUDY: To investigate their systemic and individual mechanism of each compound in combination GRS. MATERIALS AND METHODS: The mice model of MI/R and hypoxia/reoxygenation (H/R)-induced cardiomyocytes injury were performed to explore the respective characteristics of each compound in GRS against myocardial injury. RESULTS: Each component in the combination GRS attenuated MI/R injury as evidenced by decreased myocardial infarct size, ameliorated histological features, and improved biochemical indicators. Meanwhile, ingredient G, R and S in combination also individually performed a significant decrease of apoptotic index in MI/R mice and H/R-induced cardiomyocytes injury. Mechanistically, component G in GRS could markedly increase the ATP content in cardiomyocytes through activation of AMPKα phosphorylation. Interestingly, the anti-apoptotic actions of G were profoundly attenuated by knockdown of AMPKα, while no alteration was observed on composition R and S. Moreover, component R in GRS significantly reduced the IL-6 and TNF-α mRNA expression, as well as the content of IL-6 via the modulation of NF-κB signaling pathway. Further, component S exhibited the most powerful anti-oxidative capacity in GRS and remarkably decreased the production of MDA and ROS, and potential mechanisms might at least in part through activating the Akt-14-3-3 signaling pathway and inhibiting the phosphorylation of Bad and ERK1/2. CONCLUSIONS: Our results indicated that the respective mechanism of each compound in combination GRS against MI/R injury might closely associated with energy metabolism modulation, suppression of inflammation and oxidative stress.

Synergistic Effect of a Pleuromutilin Derivative with Tetracycline against Streptococcus suis In Vitro and in the Neutropenic Thigh Infection Model.

Tetracycline (TET) has been widely used in the treatment of Streptococcus suis (S. suis) infection. However, it was found that the efficacy of many antibiotics in S. suis decreased significantly, especially tetracycline. In this study, GML-12 (a novel pleuromutilin derivative) was used in combination with TET against 12 S. suis isolates. In the checkerboard assay, the TET/GML-12 combination exhibited synergistic and additive effects against S. suis isolates (n = 12). In vitro time-killing assays and in vivo therapeutic experiments were used to confirm the synergistic effect of the TET/GML-12 combination against S. suis strains screened based on an FICI ≤ 0.5. In time-killing assays, the TET/GML-12 combination showed a synergistic effect or an additive effect against three isolates with a bacterial reduction of over 2.4-log10 CFU/mL compared with the most active monotherapy. Additionally, the TET/GML-12 combination displayed potent antimicrobial activity against four isolates in a mouse thigh infection model. These results suggest that the TET/GML-12 combination may be a potential therapeutic strategy for S. suis infection.

Schisandrin B improves cerebral ischemia and reduces reperfusion injury in rats through TLR4/NF-κB signaling pathway inhibition.

It has been established that poor outcomes in ischemic stroke patients are associated with the post-reperfusion inflammatory response and up-regulation of TLR4. Therefore, suppression of the TLR4 signaling pathway constitutes a potential neuroprotective therapeutic strategy. Schisandrin B, a compound extracted from Schisandra chinensis, has been shown to possess anti-inflammatory and neuroprotective properties. However, the mechanism remains unclear. In the present study, the therapeutic effect of schisandrin B was assessed following cerebral ischemia and reperfusion (I/R) injury in a model of middle cerebral artery occlusion and reperfusion (MCAO/R) in rats. The effects of schisandrin B were investigated with particular emphasis on TLR4 signal transduction and on the inflammatory response. Schisandrin B treatment conferred significant protection against MCAO/R injury, as evidenced by decreases in infarct volume, neurological score, and the number of apoptotic neurons and inflammatory signaling molecules. ABBREVIATIONS: I/R: schemia/reperfusion; IL: interleukin; MCAO/R: middle cerebral artery occlusion and reperfusion; NF-κB: nuclear; TLR4: Toll-like receptor 4; TNF-α: tumor necrosis factor-α.

Albendazole-Schisandrin B Co-Therapy on Angiostrongylus cantonensis-Induced Meningoencephalitis in Mice.

Abstract: Currently, Angiostrongylus cantonensis infections are predominantly treated with albendazole. However, the use of albendazole can provoke certain neurological symptoms as a result of the immune response triggered by the dead worms. Therefore, treatment usually involves co-administration of corticosteroids to limit the inflammatory reaction. Corticosteroids play a useful role in suppressing inflammation in the brain; however, long-term usage or high dosage may make it problematic.Schisandrin B, an active ingredient from Schisandra chinensis, has been shown to have anti-inflammatory effects on the brain. This study aimed to investigate the effects and potential of schisandrin B in combination with albendazole to treat Angiostrongylus-induced meningoencephalitis. Here, we show that albendazole-schisandrin B co-treatment suppressed neuroinflammation in Angiostrongylus-infected mice and increased the survival of the mice. Accordingly, albendazole-schisandrin B co-treatment significantly inhibited inflammasome activation, pyroptosis, and apoptosis. The sensorimotor functions of the mice were also repaired after albendazole-schisandrin B treatment. Immune response was shown to shift from Th2 to Th1, which reduces inflammation and enhances immunity against A. cantonensis. Collectively, our study showed that albendazole-schisandrin B co-therapy may be used as an encouraging treatment for Angiostrongylus-induced meningoencephalitis.

Lefamulin vs moxifloxacin for community-acquired bacterial pneumonia.

Lefamulin is a novel pleuromutilin antibiotic with potent in vitro activity against key community-acquired bacterial pneumonia (CABP) pathogens. However, the clinical efficacy and safety of lefamulin for treating CABP remains unclear.An integrated analysis of 2 phase III trials investigating the clinical efficacy and safety of lefamulin vs moxifloxacin in the treatment of CABP was conducted.A total of 1289 patients (lefamulin group: 646 and moxifloxacin group: 643) were included in this analysis. The early clinical response rate was 89.3% and 90.5% among lefamulin and moxifloxacin group, respectively. Lefamulin was noninferior to moxifloxacin (89.3% vs 90.5%, RR: 0.99, 95% CI: 0.95-1.02, I = 0%). In terms of clinical response at test of cure, no significant difference was observed between the lefamulin and moxifloxacin groups (for modified intention to treat population, RR: 0.98, 95% CI: 0.94-1.02, I = 0%; for clinically evaluable population, RR: 0.96, 95% CI: 0.93-1.00, I = 0%). In the subgroup analysis, the early clinical response rate at early clinical assessment and clinical response rate at test of cure of lefamulin was similar to that of moxifloxacin across different subgpopulations and all baseline CABP pathogens. Lefamulin was associated with a similar risk of adverse events as moxifloxacin.Clinical efficacy and tolerability for lefamulin in the treatment of CABP were similar to those for moxifloxacin.

Preventive Effects of Schisandrin A, A Bioactive Component of Schisandra chinensis, on Dexamethasone-Induced Muscle Atrophy.

Muscle wasting is caused by various factors, such as aging, cancer, diabetes, and chronic kidney disease, and significantly decreases the quality of life. However, therapeutic interventions for muscle atrophy have not yet been well-developed. In this study, we investigated the effects of schisandrin A (SNA), a component extracted from the fruits of Schisandra chinensis, on dexamethasone (DEX)-induced muscle atrophy in mice and studied the underlying mechanisms. DEX+SNA-treated mice had significantly increased grip strength, muscle weight, and muscle fiber size compared with DEX+vehicle-treated mice. In addition, SNA treatment significantly reduced the expression of muscle degradation factors such as myostatin, MAFbx (atrogin1), and muscle RING-finger protein-1 (MuRF1) and enhanced the expression of myosin heavy chain (MyHC) compared to the vehicle. In vitro studies using differentiated C2C12 myotubes also showed that SNA treatment decreased the expression of muscle degradation factors induced by dexamethasone and increased protein synthesis and expression of MyHCs by regulation of Akt/FoxO and Akt/70S6K pathways, respectively. These results suggest that SNA reduces protein degradation and increases protein synthesis in the muscle, contributing to the amelioration of dexamethasone-induced muscle atrophy and may be a potential candidate for the prevention and treatment of muscle atrophy.

Enhanced antitumor efficacy using epirubicin and schisandrin B co-delivery liposomes modified with PFV via inhibiting tumor metastasis.

As a malignant tumor, breast cancer is very prone to metastasis. Chemotherapy is one of the most common means for treating breast cancer. However, due to the serious metastasis and the poor targeting effect of traditional chemotherapeutic drugs, even after years of efforts, the therapeutic effect is still unsatisfied. Therefore, in this study, we constructed a kind of PFV modified epirubicin plus schisandrin B liposomes to solve the above disadvantages. In vitro experiments showed that the targeting liposomes with ideal physicochemical property could increase the cytotoxicity of MDA-MB-435S cells, destroy the formation of vasculogenic mimicry (VM), and inhibit tumor invasion and migration. Action mechanisms indicated that the inhibition of targeting liposomes on tumor metastasis was attributed to the regulation of the expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 (MMP-9), vimentin (VIM), and E-cadherin (E-cad). In vivo pharmacodynamic experiments showed that the targeting liposomes could significantly improve the antitumor effect in mice. H&E staining and TUNEL results showed that the targeting liposomes could promote the apoptosis of tumor cells. Hence, the PFV modified epirubicin plus schisandrin B liposomes constructed in this study provided a new therapeutic strategy for breast cancer.

Assaying Chlamydia pneumoniae Persistence in Monocyte-Derived Macrophages Identifies Dibenzocyclooctadiene Lignans as Phenotypic Switchers.

Antibiotic-tolerant persister bacteria involve frequent treatment failures, relapsing infections and the need for extended antibiotic treatment. The virulence of an intracellular human pathogen C. pneumoniae is tightly linked to its propensity for persistence and means for its chemosensitization are urgently needed. In the current work, persistence of C. pneumoniae clinical isolate CV6 was studied in THP-1 macrophages using quantitative PCR and quantitative culture. A dibenzocyclooctadiene lignan schisandrin reverted C. pneumoniae persistence and promoted productive infection. The concomitant administration of schisandrin and azithromycin resulted in significantly improved bacterial eradication compared to sole azithromycin treatment. In addition, the closely related lignan schisandrin C was superior to azithromycin in eradicating the C. pneumoniae infection from the macrophages. The observed chemosensitization of C. pneumoniae was associated with the suppression of cellular glutathione pools by the lignans, implying to a previously unknown aspect of chlamydia-host interactions. These data indicate that schisandrin lignans induce a phenotypic switch in C. pneumoniae, promoting the productive and antibiotic-susceptible phenotype instead of persistence. By this means, these medicinal plant -derived compounds show potential as adjuvant therapies for intracellular bacteria resuscitation.

Schisandrin A ameliorates MPTP-induced Parkinson's disease in a mouse model via regulation of brain autophagy.

Schisandrin A (Sch A) is one of the principal bioactive lignans isolated from Fructus schisandrae. In this study, we demonstrated its protective effect and biochemical mechanism of action in a 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine-induced mouse model of Parkinson's disease. Sch A significantly ameliorated behavioural abnormalities and increased the number of nigral dopaminergic neurons detected by tyrosine hydroxylase immunohistochemistry. Pre-treatment with Sch A significantly decreased the levels of the inflammatory mediators IL-6, IL-1ß, and TNF-α and markedly improved antioxidant defences by inhibiting the activity of MDA and increasing that of SOD. Furthermore, Sch A activated expression of the autophagy-related proteins LC3-II, beclin1, parkin, and PINK1 and increased mTOR expression. Taken together, these findings indicate that Sch A has neuroprotective effects against the development of Parkinson's disease via regulation of brain autophagy.

The Pharmacokinetic Prediction of Cyclosporin A after Coadministration with Wuzhi Capsule.

We aim to describe the influence of principal ingredients of Wuzhi capsule, schisandrin A (SIA) and schisantherin A (STA), on the pharmacokinetics of cyclosporin A (CsA) and to quantify the herb-drug interactions (HDIs) between SIA, STA, and CsA. CsA is a first-line immunosuppressant for anti-rejection therapy after solid organ transplantation, while narrow therapeutic window associated with strong hepatotoxicity largely limited its use. Wuzhi capsule, a liver-protective drug, was approved for coadministration with CsA to reduce the hepatotoxicity. There are few studies exploring HDIs of CsA when coadministered with Wuzhi capsule. The essential adjusted physicochemical data and pharmacokinetic parameters of SIA, STA, and CsA were collected. Then physiologically based pharmacokinetic (PBPK) models of SIA, STA, and CsA were built and verified in healthy subjects using Simcyp respectively. The refined PBPK models were used to estimate potential HDIs between CsA and SIA, STA. The simulated plasma concentration-time curves of CsA, SIA, and STA were in good accordance with the observed profiles respectively. CsA pharmacokinetics were improved after coadministration. After a single dose and multiple doses, the area under the plasma concentration-time curve (AUC) of CsA was increased by 47% and 226% when coadministered with STA, respectively, and by 8% and 36% when coadministered with SIA, respectively. PBPK models sufficiently described the pharmacokinetics of CsA, SIA, and STA. Compared with SIA, STA inhibited CsA metabolism to a greater extent. Our result revealed the dose of CsA can be reduced to maintain similar profile when used concomitantly with Wuzhi capsule.

Introduction: lefamulin and pharmacokinetic/pharmacodynamic rationale to support the dose selection of lefamulin.

Lefamulin is the first semisynthetic pleuromutilin being developed for oral and intravenous administration. The drug selectively inhibits prokaryotic ribosomal protein synthesis by binding to the peptidyl transferase centre via four H-bonds and other interactions, resulting in an 'induced fit' that tightens the binding pocket around lefamulin. This unique mechanism of action has been associated with a low probability of cross-resistance to other antimicrobial classes commonly used to treat community-acquired bacterial pneumonia (CABP). This Supplement, entitled 'Pharmacokinetic and pharmacodynamic analyses and dose rationale for lefamulin, a novel pleuromutilin antibiotic, for the treatment of community-acquired bacterial pneumonia', is intended to be a valuable resource for both clinicians and researchers. It provides the essential pharmacokinetic and pharmacodynamic data on lefamulin that were used to support the optimal dose selection of lefamulin for the safe and effective treatment of CABP in adults.

Pharmacokinetic/pharmacodynamic target attainment analyses to support intravenous and oral lefamulin dose selection for the treatment of patients with community-acquired bacterial pneumonia.

OBJECTIVES: Lefamulin is a semi-synthetic intravenous (iv) and oral pleuromutilin antibiotic active against community-acquired bacterial pneumonia (CABP) pathogens. Pharmacokinetic/pharmacodynamic (PK/PD) target attainment analyses were carried out to evaluate lefamulin 150 mg iv q12h and 600 mg orally q12h under fed and fasted conditions for the treatment of patients with CABP. METHODS: The analyses undertaken used a population PK model based on Phase 1 PK data, non-clinical PK/PD targets for efficacy and in vitro surveillance data for Streptococcus pneumoniae (SP) and Staphylococcus aureus (SA), and Monte Carlo simulation. Percentage probabilities of PK/PD target attainment by MIC on day 1 were determined using median total-drug epithelial lining fluid (ELF) and free-drug plasma AUC:MIC ratio targets associated with 1 and 2 log10 cfu reductions from baseline. RESULTS: Percentage probabilities of attaining the total-drug ELF AUC:MIC ratio target for a 1 log10 cfu reduction from baseline for SP were ≥99.2% at the MIC90 of 0.12 mg/L and 96.7%, 82.1% and 96.3% for iv and oral dosing regimens under fed and fasted conditions, respectively, at the MIC99 of 0.25 mg/L. Percentage probabilities of attaining the free-drug plasma AUC:MIC target for the same endpoint at the SP MIC99 were 100% for each regimen. For the SA MIC90 of 0.12 mg/L and AUC:MIC ratio targets for the same endpoint, percentage probabilities were 92.7%-100% for iv and oral dosing regimens. CONCLUSIONS: These data provide support for lefamulin 150 mg iv q12h and 600 mg orally q12h for the treatment of patients with CABP and suggest that doses may not need to be taken under fasted conditions.

Pharmacokinetics and tolerability of lefamulin following intravenous and oral dosing.

OBJECTIVES: To explore the pharmacokinetics (PK) of oral and intravenous (iv) lefamulin after single and multiple doses, and the effect of food on bioavailability. METHODS: Lefamulin PK was examined in four studies. In Study 1, PK was assessed in patients with acute bacterial skin and skin structure infections who received repeated iv lefamulin q12h (150 mg). In Study 2, a four-period crossover study, healthy subjects received a single dose of oral lefamulin [immediate-release (IR) tablet, 1 × 600 mg] in a fasted and fed state, oral lefamulin (capsule, 3 × 200 mg) in a fasted state, and iv lefamulin in a fasted state. In Study 3, a three-period crossover study, healthy males received a single oral lefamulin dose (IR) in the following states: fasted, fasted followed by a high-calorie meal 1 h post-dose, and fed. Study 4 had two parts; in part A, healthy males received a single lefamulin dose (IR) in a fasted and fed state; in part B, subjects received repeated doses of lefamulin (IR, q12h) or placebo. Adverse events (AEs) were recorded in each study. RESULTS: Single and repeated dosing of iv and oral lefamulin resulted in comparable exposure. Intravenous and oral lefamulin (given fasted or with a meal 1 h post-dose) resulted in bioequivalence. Bioequivalence was not established between oral lefamulin in the fed state and iv or oral administration in the fasted state. All AEs were mild or moderate in severity, no serious AEs were reported, and no participant discontinued because of an AE. CONCLUSIONS: The PK of lefamulin supports successful switch from iv to oral therapy; lefamulin was generally well tolerated.