Effect of Prophylactic Use of Silymarin on Anti-tuberculosis Drugs Induced Hepatotoxicity

Are alterations needed in Silybum marianum (Silymarin) administration practices? A novel outlook and meta-analysis on randomized trials targeting liver injury

It is widely believed that Silybum marianum (Silymarin) alleviates liver injury arising from various etiologies with different degrees of damage through its anti-inflammatory and antioxidant activities. This meta-analysis investigated the effects of silymarin administration on serum levels of liver enzymes including AST, ALT and ALP. From inception to November, 2023, a comprehensive literature search was conducted. Inclusion criteria for this study were randomized trials that provided sufficient data for each group at the beginning and end of the follow-up period. Ultimately, 55 studies with a total of 3545 patients were included. Comprehensive Meta-Analysis (CMA) V4 software was used for meta-analysis. Begg's funnel plot symmetry status, Begg's rank correlation, and Egger's weighted regression tests were used to examine potential publication bias. According to the findings of this meta-analysis silymarin administration showed a significant reduction in AST (SMD [95% CI]: - 0.670 [- 0.931, - 0.408], p-value = 0.000), and ALT (SMD [95% CI]: - 0.912 [- 1.177, - 0.646], p-value = 0.000) levels. While it had no statistically significant effect on ALP level (SMD [95% CI]: - 0.236 [- 1.929, 1.458], p-value = 0.159). Meta-regression analysis showed that there is no significant association between dose, age, BMI, treatment duration and hepatoprotective effects of silymarin. In subgroup analysis, a greater reduction in liver enzymes levels was observed in patients under 50 years old. The subgroup analysis was also showed significant decrease in AST and ALT levels for patients with BMI less than 30, while silymarin treatment had no significant effects on AST and ALT levels in patients with BMI ≥ 30. Silymarin at a dose of less than 400 mg and treatment duration ≤ 2 months showed greater decreasing effects on AST and ALT levels compared to its high doses and longer treatment duration. AST and ALT levels significantly decreased in patients with NAFLD and viral hepatitis, while it had no significant hepatoprotective effects in patients with drugs induced liver injury and alcohol-related liver disease. Modifying the dose and treatment duration with silymarin is recommended in patients with various causes of liver damage.

Repurposed Drugs and Plant-Derived Natural Products as Potential Host-Directed Therapeutic Candidates for Tuberculosis

Tuberculosis (TB) is one of the leading causes of death due to infectious disease. It is a treatable disease; however, conventional treatment requires a lengthy treatment regimen with severe side effects, resulting in poor compliance among TB patients. Intermittent drug use, the non-compliance of patients, and prescription errors, among other factors, have led to the emergence of multidrug-resistant TB, while the mismanagement of multidrug-resistant TB (MDR-TB) has eventually led to the development of extensively drug-resistant tuberculosis (XDR-TB). Thus, there is an urgent need for new drug development, but due to the enormous expenses and time required (up to 20 years) for new drug research and development, new therapeutic approaches to TB are required. Host-directed therapies (HDT) could be a most attractive strategy, as they target the host defense processes instead of the microbe and thereby may prevent the alarming rise of MDR- and XDR-TB. This paper reviews the progress in HDT for the treatment of TB using repurposed drugs which have been investigated in clinical trials (completed or ongoing) and plant-derived natural products that are in clinical or preclinical trial stages. Additionally, this review describes the existing challenges to the development and future research directions in the implementation of HDT.

Effects of silymarin supplementation on liver and kidney functions: A systematic review and dose-response meta-analysis

It is suggested that supplementation with silymarin (SIL) has beneficial impacts on kidney and liver functions. This systematic review and dose-response meta-analysis assessed the impact of SIL administration on certain hepatic, renal, and oxidative stress markers. A systematic search was conducted in various databases to identify relevant trials published until January 2023. Randomized controlled trials (RCTs) that evaluated the effects of SIL on kidney and liver markers were included. A random-effects model was used for the analysis and 41 RCTs were included. The pooled results indicated that SIL supplementation led to a significant reduction in serum levels of alkaline phosphatase, alanine transaminase, creatinine, and aspartate aminotransferase, along with a substantial elevation in serum glutathione in the SIL-treated group compared to their untreated counterparts. In addition, there was a nonsignificant decrease in serum levels of gamma-glutamyl transferase, malondialdehyde (MDA), total bilirubin, albumin (Alb), total antioxidant capacity, and blood urea nitrogen. Sub-group analyses revealed a considerable decline in MDA and Alb serum values among SIL-treated participants with liver disease in trials with a longer duration (≥12 weeks). These findings suggest that SIL may ameliorate certain liver markers with potential hepatoprotective effects, specifically with long-term and high-dose supplementation. However, its nephroprotective effects and impact on oxidative stress markers were not observed. Additional high-quality RCTs with longer durations are required to determine the clinical efficacy of SIL supplementation on renal and oxidative stress markers.

Unveiling the therapeutic promise of natural products in alleviating drug-induced liver injury: Present advancements and future prospects

Drug-induced liver injury (DILI) refers to adverse reactions to small chemical compounds, biological agents, and medical products. These reactions can manifest as acute or chronic damage to the liver. From 1997 to 2016, eight drugs, including troglitazone, nefazodone, and lumiracoxib, were removed from the market due to their liver-damaging effects, which can cause diseases. We aimed to review the recent research on natural products and their bioactive components as hepatoprotective agents in mitigating DILI. Recent articles were fetched via searching the PubMed, PMC, Google Scholar, and Web of Science electronic databases from 2010 to January 2023 using relevant keywords such as "natural products," "acetaminophen," "antibiotics," "paracetamol," "DILI," "hepatoprotective," "drug-induced liver injury," "liver failure," and "mitigation." The studies reveal that the antituberculosis drug (acetaminophen) is the most frequent cause of DILI, and natural products have been largely explored in alleviating acetaminophen-induced liver injury. They exert significant hepatoprotective effects by preventing mitochondrial dysfunction and inflammation, inhibiting oxidative/nitrative stress, and macromolecular damage. Due to the bioavailability and dietary nature, using natural products alone or as an adjuvant with existing drugs is promising. To advance DILI management, it is crucial to conduct well-designed randomized clinical trials to evaluate natural products' efficacy and develop new molecules clinically. However, natural products are a promising solution for remedying drug-induced hepatotoxicity and lowering the risk of DILI.

Systematic review and network meta-analysis of efficacy and safety of interventions for preventing anti-tuberculosis drug induced liver injury

Anti-tuberculosis drug induced liver injury (Anti-TB DILI) is the most common adverse events (AEs) necessitating therapy interruption but there is no preventing regimen. This study aimed to examine the efficacy and safety of herbs/alternative medicines for preventing anti-TB DILI. Relevant articles were identified through a systematic search in 5 international databases from inception till March 2022. All randomized controlled trials (RCT) assessing the effects of herbal or alternative medicines against anti-TB DILI were included. The network meta-analysis (NMA) was used to synthesize the evidence for preventing hepatotoxicity using a random-effects model. A total of 3423 patients from 14 RCTs were included. The NMA indicated that supplementation of Turmeric plus Tinospora cordifolia (RR 0.07; 95% CI 0.02 to 0.28), and N-acetyl cysteine (NAC) (RR 0.09; 95% CI 0.01 to 0.75) significantly reduced the incidence of anti-TB DILI compared with placebo. In addition, poly herbal product significantly reduced alkaline phosphatase (ALP) (MD - 21.80; 95% CI - 33.80 to - 9.80) and total bilirubin (Tbil) compared with placebo (MD - 0.51; 95% CI - 0.76 to - 0.26). There was no statistically significant difference in the occurrence of AEs in any intervention. In conclusion, Turmeric plus Tinospora cordifolia, NAC and poly-herbal product may provide benefit for preventing anti-TB DILI in TB patients. However, these findings are based on a small number of studies. Additional studies are warranted to confirm the findings.

Mechanistic Insights into the Pharmacological Significance of Silymarin

Medicinal plants are considered the reservoir of diverse therapeutic agents and have been traditionally employed worldwide to heal various ailments for several decades. Silymarin is a plant-derived mixture of polyphenolic flavonoids originating from the fruits and akenes of Silybum marianum and contains three flavonolignans, silibinins (silybins), silychristin and silydianin, along with taxifolin. Silybins are the major constituents in silymarin with almost 70–80% abundance and are accountable for most of the observed therapeutic activity. Silymarin has also been acknowledged from the ancient period and is utilized in European and Asian systems of traditional medicine for treating various liver disorders. The contemporary literature reveals that silymarin is employed significantly as a neuroprotective, hepatoprotective, cardioprotective, antioxidant, anti-cancer, anti-diabetic, anti-viral, anti-hypertensive, immunomodulator, anti-inflammatory, photoprotective and detoxification agent by targeting various cellular and molecular pathways, including MAPK, mTOR, β-catenin and Akt, different receptors and growth factors, as well as inhibiting numerous enzymes and the gene expression of several apoptotic proteins and inflammatory cytokines. Therefore, the current review aims to recapitulate and update the existing knowledge regarding the pharmacological potential of silymarin as evidenced by vast cellular, animal, and clinical studies, with a particular emphasis on its mechanisms of action.

Mechanism of drug-induced liver injury and hepatoprotective effects of natural drugs

Drug-induced liver injury (DILI) is a common adverse drug reaction (ADR) and a serious threat to health that affects disease treatments. At present, no targeted clinical drugs are available for DILI. Traditional natural medicines have been widely used as health products. Some natural medicines exert specific hepatoprotective effects, with few side effects and significant clinical efficacy. Thus, natural medicines may be a promising direction for DILI treatment. In this review, we summarize the current knowledge, common drugs and mechanisms of DILI, as well as the clinical trials of natural drugs and their bioactive components in anticipation of the future development of potential hepatoprotective drugs.

Oxidative Stress in Drug-Induced Liver Injury (DILI): From Mechanisms to Biomarkers for Use in Clinical Practice

Idiosyncratic drug-induced liver injury (DILI) is a type of hepatic injury caused by an uncommon drug adverse reaction that can develop to conditions spanning from asymptomatic liver laboratory abnormalities to acute liver failure (ALF) and death. The cellular and molecular mechanisms involved in DILI are poorly understood. Hepatocyte damage can be caused by the metabolic activation of chemically active intermediate metabolites that covalently bind to macromolecules (e.g., proteins, DNA), forming protein adducts-neoantigens-that lead to the generation of oxidative stress, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress, which can eventually lead to cell death. In parallel, damage-associated molecular patterns (DAMPs) stimulate the immune response, whereby inflammasomes play a pivotal role, and neoantigen presentation on specific human leukocyte antigen (HLA) molecules trigger the adaptive immune response. A wide array of antioxidant mechanisms exists to counterbalance the effect of oxidants, including glutathione (GSH), superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX), which are pivotal in detoxification. These get compromised during DILI, triggering an imbalance between oxidants and antioxidants defense systems, generating oxidative stress. As a result of exacerbated oxidative stress, several danger signals, including mitochondrial damage, cell death, and inflammatory markers, and microRNAs (miRNAs) related to extracellular vesicles (EVs) have already been reported as mechanistic biomarkers. Here, the status quo and the future directions in DILI are thoroughly discussed, with a special focus on the role of oxidative stress and the development of new biomarkers.

Appropriate chemopreventive strategy for anti-tubercular therapy related liver injury is unsettled: Results from a systematic review and network meta-analysis

BACKGROUND

Role of chemoprophylaxis for prevention of antitubercular therapy-related drug-induced liver injury (ATT-DILI) is uncertain.

METHODS

Electronic databases were searched for randomized trials reporting on chemoprophylaxis agents for prevention of ATT-DILI. We included studies evaluating the role of a drug in comparison to controls/placebo. The primary outcome was the occurrence of ATT-DILI. We performed a Bayesian random-effects network meta-analysis to calculate odds ratios (ORs) and 95% credible intervals (CrI) for those arms where at least two studies were available. Additional comparative studies for these arms were also identified.

RESULTS

Fourteen studies were identified and seven included in the meta-analysis. The agents used for prevention of ATT-DILI were silymarin/silibinin (4 trials), N-acetylcysteine (NAC) (3 studies), herbal preparations (5 studies) and one study each for cholecalciferol and carnitine. Compared with controls/placebo, the odds of occurrence of hepatotoxicity with NAC was 7 * 10-17 (95% CrI: 2.8 * 10-53, 0.0053) and Silymarin was 0.68 (95% CrI: 0.084, 4.6). NAC had the highest probability of rank 1 (0.99) which was followed by Silymarin (0.004).

CONCLUSION

N-acetyl cysteine, but not Silymarin/Silibinin, appears to be beneficial in prevention of ATT-DILI. However, the results were limited by the possible risk of bias in included studies, variable definitions of ATT-DILI and limited number and category of patients.

Safety and toxicity of silymarin, the major constituent of milk thistle extract: An updated review

Milk thistle (Silybum marianum) is a medicinal plant from the Asteraceae family. Silymarin is the major constituent of milk thistle extract and is a mixture of some flavonolignans such as silybin, which is the most active component of silymarin. It is most commonly known for its hepatoprotective effect. Also, studies have shown other therapeutic effects such as anticancer, anti-Alzheimer, anti-Parkinson, and anti-diabetic, so its safety is very important. It has no major toxicity in animals. Silymarin was mutagen in Salmonella typhimurium strains in the presence of metabolic enzymes. Silybin, silydianin, and silychristin were not cytotoxic and genotoxic at concentration of 100 μM. Silymarin is safe in humans at therapeutic doses and is well tolerated even at a high dose of 700 mg three times a day for 24 weeks. Some gastrointestinal discomforts occurred like nausea and diarrhea. One clinical trial showed silymarin is safe in pregnancy, and there were no anomalies. Consequently, caution should be exercised during pregnancy, and more studies are needed especially in humans. Silymarin has low-drug interactions, and it does not have major effects on cytochromes P-450. Some studies demonstrated that the use of silymarin must be with caution when co-administered with narrow therapeutic window drugs.

Prophylactic Therapy of Silymarin (Milk Thistle) on Antituberculosis Drug-Induced Liver Injury: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Prophylactic therapy with silymarin to prevent the development of antituberculosis drug-induced liver injury (anti-TB DILI) has been under debate. We aimed to evaluate the effect of silymarin in the prevention of anti-TB DILI.

METHODS

We searched MEDLINE, PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) up to 30th November 2018. Randomized controlled trials (RCTs) that compared silymarin and placebo to prevent anti-TB DILI were included. All statistical analyses were conducted using STATA 12.0 software. Standardized mean difference (SMD) and risk ratio (RR) with 95% confidence intervals (CIs) were used to evaluate the effect of silymarin. The quality of included studies was assessed according to Cochrane handbook. Funnel plots and Egger's tests were carried out to evaluate publication bias. Sensitivity analysis was conducted to assess the influence of each study.

RESULTS

A total of 1198 patients from five RCTs (585 with silymarin and 613 with placebo groups) were included. Overall, silymarin significantly reduced the occurrence of anti-TB DILI at week 4 [RR: 0.33, 95% CI (0.15, 0.75)]. In addition, silymarin exerted protective effect on liver function in patients undergoing anti-TB drugs [SMD = - 0.15, 95% CI (-0.24, -0.07), P < 0.001 (ALT); SMD =-0.14, 95% CI (-0.23, -0.06), P = 0.001(AST); SMD =-0.12, 95% CI (-0.20, -0.03), P = 0.008 (ALP)]. Silymarin led to similar AEs in placebo groups [OR: 1.09, 95% CI (0.86, 1.39), P = 0.47].

CONCLUSION

Prophylactic therapy of silymarin is contributed to a noticeably reduced risk of development of anti-TB DILI four weeks after the initiation. In addition, silymarin significantly improved the liver function in patients who are receiving anti-TB drugs.

Evaluation of Silymarin for management of anti-tuberculosis drug induced liver injury: a randomized clinical trial

AIM

This study was performed to evaluate the potential efficacy of silymarin in the management of anti-tuberculosis medication's induced liver injury.

BACKGROUND

Hepatic toxicity is the most serious complication in treatment of tuberculosis.

METHODS

In a randomized double blind clinical trial (ACTRN12610000643077), 55 cases with hepatotoxicity caused by anti-tuberculosis drugs were divided into two groups. Informed consents were obtained. The intervention group received silymarin and the control group received placebo. Severity of liver injury, the duration necessary for normalization of liver function and hospital stay were compared between the two groups.

RESULTS

There was not any statistically significant difference in the rate of adverse effects between silymarin and placebo groups.

CONCLUSION

Although silymarin is considered a safe herbal medication, it was not effective to treat hepatic toxicity of anti-tuberculosis drugs.