Development and validation of two liquid chromatography-tandem mass spectrometry methods for the determination of silibinin and silibinin hemisuccinate in human plasma

Urinary excretion of silibinin diastereoisomers and their conjugated metabolites in rat and human at different dosages

Silibinin is a mixture of two flavonoid lignan silibinins A and B from the seeds of milk thistle (Silybum marianum L.). Using UPLC/Q-TOFMS, a total of 18 metabolites were identified in rat and human urine samples after oral administration of Silibinin Capsule. Furthermore, nine glucuronides and/or sulfated metabolites and two prototype compounds were simultaneously quantified in rat urine after oral administration of Silibinin Capsule at 50 and 100 mg/kg. Over a 72-h period, 27.6% and 23.3% of the silibinin were excreted in the forms of eleven metabolites in urine, among which, 5 major metabolites, including silibinin A-7-O-β-glucuronide (SA-7G), silibinin B-7-O-β-glucuronide (SB-7G), silibinin A-5-O-β-glucuronide (SA-5G), silibinin B-5-O-β-glucuronide (SB-5G) and silibinin A-20-O-glucuronide (SA-20G), accounted for 20.5% and 15.5% of the dosages separatively at doses of 50 and 100 mg/kg. These results suggested that glucuronidation at the C7-, C5- and C20- hydroxyls was the primary metabolic pathway of silibinin diastereoisomers in vivo. The present results provide helpful information for in vivo metabolism and clinical usage of Silibinin Capsule.

Silibinin Schiff Base Derivatives Counteract CCl4-Induced Acute Liver Injury by Enhancing Anti-Inflammatory and Antiapoptotic Bioactivities

Background

Purpose

Patients and Methods

Results

Conclusion

The milk thistle (Silybum marianum) compound Silibinin stimulates leukopoiesis from mouse embryonic stem cells

The milk thistle compound Silibinin (i.e., a 1:1 mixture of Silybin A and Silybin B) stimulates vasculogenesis of mouse embryonic stem (ES) cells. Because vasculogenesis and leukopoiesis are interrelated, the effect of Silibinin on leukopoiesis of ES cells was investigated. Treatment of differentiating ES cells with hydrosoluble Silibinin-C-2',3-dihydrogen succinate dose-dependent increased the number of CD18+ , CD45+ , and CD68+ cells, indicating leukocyte/macrophage differentiation. Silibinin treatment activated phosphoinositide 3-kinase (PI3K), AKT (protein kinase B), signal transducer and activator of transcription 3 (STAT3), stimulated hypoxia-induced factor-1α (HIF-1α), and vascular endothelial growth factor receptor 2 (VEGFR2) expression and raised intracellular nitric oxide (NO). Western blot experiments showed that upon coincubation with either the PI3K inhibitor LY294002, the STAT3 inhibitor Stattic, the AKT antagonist AKT inhibitor VIII, or the NO inhibitor L-NAME, the Silibinin-induced expression of CD18, CD45, and CD68 was abolished. Moreover, the stimulation of HIF-1α and VEGFR2 expression was blunted upon STAT3 and PI3K/AKT inhibition. Treatment of differentiating ES cells with L-NAME abolished the stimulation of VEGFR2 and VE-cadherin expression achieved with Silibinin, indicating that NO is involved in vasculogenesis and leukocyte differentiation pathways. In summary, the data of the present study demonstrate that Silibinin stimulates leukocyte differentiation of ES cells, which is associated to vasculogenesis and regulated by PI3K/AKT-, STAT3-, and NO-mediated signaling.

A Lead-In with Silibinin Prior to Triple-Therapy Translates into Favorable Treatment Outcomes in Difficult-To-Treat HIV/Hepatitis C Coinfected Patients

Background

The efficacy of first-generation protease inhibitor based triple-therapy against hepatitis C virus (HCV) infection is limited in HIV/HCV-coinfected patients with advanced liver fibrosis and non-response to previous peginterferon-ribavirin. These patients have a low chance of achieving a sustained virologic response (SVR) using first generation triple-therapy, with a success rate of only 20%. We investigated the efficacy and safety of lead-in therapy with intravenous silibinin followed by triple-therapy in this difficult-to-treat patient group.

Methodology

Inclusion criteria were HIV/HCV coinfection with advanced liver fibrosis and documented previous treatment failure on peginterferon-ribavirin. The intervention was a lead-in therapy with intravenous silibinin 20 mg/kg/day for 14 days, followed by triple-therapy (peginterferon-ribavirin and telaprevir) for 12 weeks, and peginterferon-ribavirin alone for 36 weeks. Outcome measurements were HCV-RNA after silibinin lead-in and during triple-therapy, SVR data at week 12, and safety and tolerability of silibinin.

Results

We examined sixteen HIV/HCV-coinfected patients with previous peginterferon-ribavirin failure, of whom 14 had a fibrosis grade METAVIR ≥F3. All were on successful antiretroviral therapy. Median (IQR) HCV-RNA decline after silibinin therapy was 2.65 (2.1–2.8) log10 copies/mL. Fifteen of sixteen patients (94%) had undetectable HCV RNA at weeks 4 and 12, eleven patients (69%) showed end-of-treatment response (i.e., undetectable HCV-RNA at week 48), and ten patients (63%) reached SVR at week 12 (SVR 12). Six of the sixteen patients (37%) did not reach SVR 12: One patient had rapid virologic response (RVR) (i.e., undetectable HCV-RNA at week 4) but stopped treatment at week 8 due to major depression. Five patients had RVR, but experienced viral breakthroughs at week 21, 22, 25, or 32, or a relapse at week 52. The HIV RNA remained below the limit of detection in all patients during the complete treatment period. No serious adverse events and no significant drug-drug interactions were associated with silibinin.

Conclusion

A lead-in with silibinin before triple-therapy was safe and highly effective in difficult-to-treat HIV/HCV coinfected patients, with a pronounced HCV-RNA decline during the lead-in phase, which translates into 63% SVR. An add-on of intravenous silibinin to standard of care HCV treatment is worth further exploration in selected difficult-to-treat patients.

Trial Registration

ClinicalTrials.gov NCT01816490