Effects of silymarin supplementation on blood lipids: A systematic review and meta‐analysis of clinical trials

Nephroprotective effects of silymarin and its fabricated nanoparticles against aluminum-induced oxidative stress, hyperlipidemia, and genotoxicity

BACKGROUND

Aluminum (Al) is a ubiquitous element with proven nephrotoxicity. Silymarin (SM) is a mixture of polyphenolic components extracted from Silybum marianum and exhibited protective influences. However, SM bioactivity can be enhanced by its incorporation in chitosan (CS) through the use of nanotechnology. This work proposed to assess the protective influence of SM and its loaded chitosan nanoparticles (SM-CS-NPs) on aluminum chloride (AlCl3)-induced nephrotoxicity.

METHODS

Six groups were created randomly from 42 male Wistar rats and each one contains 7 rats (n = 7). Group I, acted as a control and received water. Group II received SM (15 mg/kg/day) and group III administered with SM-CS-NPs (15 mg/kg/day). Group IV received AlCl3 (34 mg/kg) and groups V and VI were treated with SM and SM-CS-NPs with AlCl3 respectively for 30 days.

RESULTS

AlCl3 administration significantly elevated TBARS, H2O2, and kidney function levels besides LDH activity. Whereas GSH, CAT, SOD, GPx, GST, and GR values were all substantially reduced along with protein content, and ALP activity. Additionally, significant alterations in lipid profile, hematological parameters, and renal architecture were observed. Moreover, TNF-α, TGF-β, and MMP9 gene expression were upregulated in kidney tissues. The administration of SM or its nanoparticles followed by AlCl3 intoxication attenuated renal dysfunction replenished the antioxidant system, and downregulated TNF-α, TGF-β, and MMP9 gene expression in renal tissues compared to the AlCl3 group.

CONCLUSION

SM-CS-NPs have more pronounced appreciated protective effects than SM and have the proficiency to balance oxidant/antioxidant systems in addition to their anti-inflammatory effect against AlCl3 toxicity.

Impacts of Supplementation with Silymarin on Cardiovascular Risk Factors: A Systematic Review and Dose-Response Meta-Analysis

It has been suggested that silymarin (SIL) supplementation has positive effects on cardiovascular health and reduces the risk of cardiometabolic syndrome (CMS). This systematic review and dose-response meta-analysis assessed the impacts of SIL administration on cardiovascular risk factors. A systematic search of multiple databases was performed to identify eligible controlled trials published up to January 2023. The analysis used a random-effects model and included 33 trials with 1943 participants. It was revealed that SIL supplementation led to a notable reduction in serum levels of fasting blood glucose (FBG) (weighted mean difference (WMD): -21.68 mg/dL, 95% CI: -31.37, -11.99; p < 0.001), diastolic blood pressure (DBP) (WMD: -1.25 mmHg; 95% CI: -2.25, -0.26; p = 0.013), total cholesterol (TC) (WMD: -13.97 mg/dL, 95% CI: -23.09, -4.85; p = 0.003), triglycerides (TG) (WMD: -26.22 mg/dL, 95% CI: -40.32, -12.12; p < 0.001), fasting insulin (WMD: -3.76 mU/mL, 95% CI: -4.80, -2.72; p < 0.001), low-density lipoprotein (LDL) (WMD: -17.13 mg/dL, 95% CI: -25.63, -8.63; p < 0.001), and hemoglobin A1C (HbA1c) (WMD: -0.85%, 95% CI: -1.27, -0.43; p < 0.001) in the SIL-treated groups compared to their untreated counterparts. In addition, there were no substantial differences in body mass index (BMI), systolic blood pressure (SBP), C-reactive protein (CRP), body weight, and high-density lipoprotein (HDL) between the two groups. These outcomes suggest that SIL consumption reduces certain CMS risk factors and has favorable impacts on lipid and glycemic profiles with potential hypotensive effects. These findings should be supported by additional trials with larger sample sizes and longer durations.

Bio-Actives from Natural Products with Potential Cardioprotective Properties: Isolation, Identification, and Pharmacological Actions of Apigenin, Quercetin, and Silibinin

Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality worldwide. As a result, pharmaceutical and non-pharmaceutical interventions modifying risk factors for CVDs are a top priority of scientific research. Non-pharmaceutical therapeutical approaches, including herbal supplements, have gained growing interest from researchers as part of the therapeutic strategies for primary or secondary prevention of CVDs. Several experimental studies have supported the potential effects of apigenin, quercetin, and silibinin as beneficial supplements in cohorts at risk of CVDs. Accordingly, this comprehensive review focused critically on the cardioprotective effects/mechanisms of the abovementioned three bio-active compounds from natural products. For this purpose, we have included in vitro, preclinical, and clinical studies associated with atherosclerosis and a wide variety of cardiovascular risk factors (hypertension, diabetes, dyslipidemia, obesity, cardiac injury, and metabolic syndrome). In addition, we attempted to summarize and categorize the laboratory methods for their isolation and identification from plant extracts. This review unveiled many uncertainties which are still unexplored, such as the extrapolation of experimental results to clinical practice, mainly due to the small clinical studies, heterogeneous doses, divergent constituents, and the absence of pharmacodynamic/pharmacokinetic analyses.

Effect of garlic extract on markers of lipid metabolism and inflammation in coronary artery disease (CAD) patients: A systematic review and meta-analysis

Several preclinical studies have focused on the beneficial effects of garlic on cardiovascular diseases, but the results were inconsistent. We performed a systematic review and meta-analysis on the effect of garlic powder tablets and aged garlic extract (AGE) in CAD patients, mainly focusing on blood pressure, coronary artery calcification, lipid profile, and inflammatory markers. We searched PubMed, Cochrane CENTRAL, and Google Scholar to identify randomized controlled trials which examined garlic's effect on CAD patients. The standardized mean difference with 95% CI was calculated using fixed-effect or random-effect models. Garlic has shown statistically significant changes of HDL (SMD = 0.18; 95% CI = -0.00 to 0.37; p = .05); LDL (SMD = -0.27; 95% CI = -0.46 to -0.08; p = .004), apolipoprotein-A (SMD = 0.68; 95% CI = 0.24 1.13; p = .002), C-RP (SMD = -0.59; 95% CI = -0.92 to -0.25; p = .0007), IL-6 (SMD = -1.08; 95% CI = -2.17 to 0.01; p = .05), homocysteine (SMD = -0.66; 95% CI = -1.04 to -0.28; p = .0007) and CAC score (SMD = -1.61; 95% CI = -2.66 to -0.57; p = .003). In the case of subgroup analysis, the overall effect was significantly effective in reducing TC, LDL levels and improving HDL levels in CV risk patients. Our study findings provide consistent evidence that intake of garlic reduces CVD risk factors. However, garlic could be considered a safe natural medicine to debilitate inflammation in CAD patients.

A Comprehensive Review of the Cardiovascular Protective Properties of Silibinin/Silymarin: A New Kid on the Block

Silibinin/silymarin has been used in herbal medicine for thousands of years and it is well-known for its hepato-protective properties. The present comprehensive literature review aimed to critically summarize the pharmacological properties of silymarin extract and its main ingredient silibinin in relation to classical cardiovascular risk factors (e.g., diabetes mellitus, etc.). We also assessed their potential protective and/or therapeutic application in cardiovascular diseases (CVDs), based on experimental and clinical studies. Pre-clinical studies including in vitro tests or animal models have predominantly implicated the following effects of silymarin and its constituents: (1) antioxidant, (2) hypolipidemic, (3) hypoglycemic, (4) anti-hypertensive and (5) cardioprotective. On the other hand, a direct amelioration of atherosclerosis and endothelial dysfunction after silymarin administration seems weak based on scarce data. In clinical trials, the most important findings are improved (1) glycemic and (2) lipid profiles in patients with type 2 diabetes mellitus and/or hyperlipidemia, while (3) the anti-hypertensive effects of silibinin/silymarin seem very modest. Finally, the changes in clinical endpoints are not robust enough to draw a firm conclusion. There are significant limitations in clinical trial design, including the great variety in doses and cohorts, the underlying conditions, the small sample sizes, the short duration and the absence of pharmacokinetic/pharmacodynamic tests prior to study commitment. More data from well-designed and high-quality pre-clinical and clinical studies are required to firmly establish the clinical efficacy of silibinin/silymarin and its possible therapeutic application in cardiovascular diseases.

Beneficial Effect of Fenofibrate and Silymarin on Hepatic Steatosis and Gene Expression of Lipogenic and Cytochrome P450 Enzymes in Non-Obese Hereditary Hypertriglyceridemic Rats

The efficacy of fenofibrate in the treatment of hepatic steatosis has not been clearly demonstrated. In this study, we investigated the effects of fenofibrate and silymarin, administered as monotherapy and in combination to existing hepatic steatosis in a unique strain of hereditary hypertriglyceridemic rats (HHTg), a non-obese model of metabolic syndrome. HHTg rats were fed a standard diet without or with fenofibrate (100 mg/kg b.wt./day) or with silymarin (1%) or with a combination of fenofibrate with silymarin for four weeks. Fenofibrate alone and in combination with silymarin decreased serum and liver triglycerides and cholesterol and increased HDL cholesterol. These effects were associated with the decreased gene expression of enzymes involved in lipid synthesis and transport, while enzymes of lipid conversion were upregulated. The combination treatment had a beneficial effect on the gene expression of hepatic cytochrome P450 (CYP) enzymes. The expression of the CYP2E1 enzyme, which is source of hepatic reactive oxygen species, was reduced. In addition, fenofibrate-induced increased CYP4A1 expression was decreased, suggesting a reduction in the pro-inflammatory effects of fenofibrate. These results show high efficacy and mechanisms of action of the combination of fenofibrate with silymarin in treating hepatic steatosis and indicate the possibility of protection against disorders in which oxidative stress and inflammation are involved.

The effects of Silymarin on the features of cardiometabolic syndrome in adults: A systematic review and meta-analysis

Some medicinal herbs and their effective components showed positive effects on the features of the cardiometabolic syndrome (CMS). The aim of the present systematic review and meta-analysis is to examine the effects of silymarin on the components of CMS in adults. Four electronic databases including PubMed/Medline, Scopus, Web of Science, and Embase were systematically searched up to December 31, 2020 to identify all eligible clinical trials. A random-effect model using DerSimonian and Laird method was used to estimate the pooled weighted mean differences (WMDs) and the 95% confidence intervals (95%CIs). Finally, 11 clinical trials met the eligibility criteria. Our results demonstrated that silymarin significantly reduced the levels of fasting blood glucose (WMD: -17.96 mg/dL, 95% CI: -32.91, -3.02;I² : 82.4%, p < 0.001), hemoglobin A1C (WMD: -1.25%, 95% CI: -2.34, 0.16; I² : 92.9%, p ˂ 0.001), total cholesterol (WMD: -17.46 mg/dL, 95% CI: -30.98, -3.95; I²  = 62.9%, p = 0.006), triglyceride (WMD: -25.70 mg/dL, 95% CI: -47.23, -4.17; I² :54.3%, p = 0.025), low-density lipoprotein-cholesterol (WMD: -10.53, 95% CI: -19.12, -1.94; I2: 37.5%, p = 0.119) and increased high-density lipoprotein- cholesterol (WMD: 3.36 mg/dL, 95% CI: 0.88, 5.84; I² : 37.4%, p = 0.120) compared to placebo. However, its effects on BMI were not statistically significant. Silymarin can be an effective complementary therapy to improve most features of CMS. However, due to high heterogeneity and limited clinical trials in some parameters, further high-quality clinical trials are needed to confirm its efficacy.

Effect of Silymarin Treatment on Circulating Bilirubin and Cardiovascular Disease Risk Factors in Healthy Men: A Single-Blind, Randomized Crossover Trial

This clinical trial (ACTRN12619001296123) investigated the impact of silymarin (Legalon®) on circulating bilirubin concentration, lipid status, systemic inflammation, and antioxidant status. The study design was a randomized, placebo-controlled, single-blind crossover trial of healthy men (18-65 years), conducted at Griffith University, Gold Coast, Australia. Participants were recruited from Griffith University and were randomized to silymarin (140 mg silymarin capsules thrice daily) or placebo (3 capsules containing mannitol taken daily) for 14 days followed by a ≥4-week washout and crossover to the other arm. The main outcomes were whether silymarin treatment would increase serum bilirubin concentration by >0.29 mg/dL, change serum lipid status (cholesterol and triglycerides), inflammation (c-reactive protein), and antioxidant capacity (ferric reducing ability of plasma) compared with baseline. Silymarin consumption (n = 17) did not affect serum concentrations of unconjugated bilirubin (0.73 versus 0.67 mg/dL, P = .79), cholesterol (185 versus 189 mg/dL, P = .19), triglycerides (94.2 versus 92.3 mg/dL, P = .79), c-reactive protein (0.17 versus 0.09 mg/dL, P = .23), or antioxidant status (6.61 versus 6.67 mg Fe²⁺ /dL, P = .40). These findings challenge previous reports and manufacturer claims of hyperbilirubinemia following silymarin treatment and are critical to guiding researchers toward an effective means to mildly elevate bilirubin, which evidence suggests could protect from cardiovascular disease.

Targeting dyslipidemia by herbal medicines: A systematic review of meta-analyses

ETHNOPHARMACOLOGICAL RELEVANCE

The worldwide increasing prevalence of dyslipidemia has become a global health concern. Various herbal remedies have been claimed to be effective for the treatment of dyslipidemia in traditional and folkloric medicine of different regions clinical trials have been conducted to investigate their efficacy. The aim of the current systematic review is to critically assess the meta-analyses of controlled trials (CT) evaluated herb medicines for dyslipidemia.

MATERIALS AND METHODS

Relevant studies from Web of Science, PubMed, Scopus, and Cochrane Library databases based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist until January 2021 have been searched. All meta-analyses which pooled studies on the effect of herbal medicines on lipid profile including total cholesterol (TC), triglyceride (TG), and low- or high-density lipoprotein cholesterol (LDL-C, HDL-C) were also included. Meta-analyses of in vitro, animal or observational studies were excluded.

RESULTS

The overall of 141 meta-analyses were revealed. Vegetable oils, phytosterols, tea, soy protein, nuts, and curcumin have been studied frequently among the herbal medicines. Among 13 meta-analyses on vegetable oils, the greater reduce of TC (18.95 mg/dl), LDL-C (16.24 mg/dl) and TG (13.69 mg/dl) were exhibited from sunflower oil. Furthermore, rice bran oil (6.65 mg/dl) increased HDL-C significantly. Phytosterols in 12 meta-analyses demonstrated significant improvements in reducing TC, LDL-C and TG as 16.4, 23.7, and 8.85 mg/dl, respectively, and rise in HDL-C as 10.6 mg/dl. The highest reduction in serum level of TC, LDL-C and TG was reported while intake Green tea; 27.57, 24.75, and 31.87 mg/dl, accordingly within 9 meta-analyses. Average improvement of lipid profiles by 6 meta-analyses on plant proteins were 23.2, 21.7, 15.06, and 1.55 mg/dl for TC, LDL-C, TG, and HDL-C, respectively. Among 11 meta-analyses on nuts, almond showed better and significant alleviations in TC (10.69 mg/dl), walnut in LDL-C (9.23 mg/dl), pistachio in TG (22.14 mg/dl), and peanut in HDL-C (2.72 mg/dl). Overall, Curcumin, Curcuminoid, and Turmeric have resulted in the reduction of TC (25.13 mg/dl), LDL-C (39.83 mg/dl), TG (33.65 mg/dl), and an increase in the HDL-C (4.31 mg/dl).

CONCLUSION

The current systematic review shed light on the use of herbal medicines for the management of dyslipidemia. However, more well-conducted CTs are required to determine effective doses of herbal medicines.

Effects of select dietary supplements on the prevention and treatment of viral respiratory tract infections: a systematic review of randomized controlled trials

Introduction: Viral respiratory tract infections (RTIs) have been recognized as a global public health burden. Despite current theories about their effectiveness, the true benefits of dietary supplements on the prevention and treatment of viral RTIs remain elusive, due to contradictory reports. Hence, we aimed to evaluate the effectiveness of dietary supplements on the prevention and treatment of viral RTIs.Areas covered: We systematically searched databases of PubMed, Web of Science, Scopus, and Google Scholar through 4 March 2020, to identify randomized controlled trials that evaluated the effects of consuming selected dietary supplements on the prevention or treatment of viral RTIs.Expert opinion: Thirty-nine randomized controlled trials (n = 16,797 participants) were eligible and included. Namely, vitamin D supplementation appeared to improve viral RTIs across cohorts particulate in those with vitamin D deficiency. Among the evaluated dietary supplements, specific lactobacillus strains were used most commonly with selected prebiotics that showed potentially positive effects on the prevention and treatment of viral RTIs. Further, ginseng extract supplementation may effectively prevent viral RTIs as adjuvant therapy. However, longitudinal research is required to confirm these observations and address the optimal dose, duration, and safety of dietary supplements being publicly recommended.

The Effect of Saffron Consumption on Liver Function: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials

BACKGROUND AND AIMS

The present systematic review and meta-analysis of randomized controlled trials aimed to determine the effects of saffron supplementation on liver function tests among adults.

METHODS

Electronic databases including PubMed, ISI Web of Science, and Scopus were searched up to January 2021. The risk of bias in individual studies was assessed using the Cochrane Collaboration tool. The overall estimates and their 95% CIs were calculated using random-effects models. Egger's test and Begg's rank-correlation were run to assess the presence of publication bias. p < 0.05 was considered statistically significant.

RESULTS

A total of 12 trials involving 608 participants were included in this systematic review and meta-analysis. Saffron supplementation had no significant effect on liver function tests including aspartate transaminase (AST) (weighted mean difference [WMD] = 0.23 U/L; 95% CI -2.22 to 2.69; p = 0.851; I2 = 74.0%), alanine aminotransferase (ALT) (WMD = -1.49 U/L; 95% CI -3.84 to 0.86; p = 0.213; I2 = 60.2%), and alkaline phosphatase (ALP) (WMD = -0.70 U/L; 95% CI -11.35 to 9.95; p = 0.898; I2 = 40.8%) compared to placebo.

CONCLUSION

Based on what was discussed, it seems that saffron supplementation could not improve liver function tests including AST, ALT, and ALP among the adult population. Further clinical trials with larger sample size, longer duration, and higher doses of saffron should be conducted exclusively among patients with liver dysfunction to elucidate the beneficial role of saffron consumption on liver function.

Phytonutrient supplements and metabolic biomarkers of cardiovascular disease: An umbrella review of meta-analyses of clinical trials

Phytonutrients exert several pharmacological effects on humans. In this study, we performed an umbrella review of the association of phytonutrient supplements (PNSs) with biomarkers of cardiovascular disease. Relevant published systematic reviews and meta-analyses of clinical trials were identified by searching PubMed, Embase, and Cochrane Library until July 4, 2020. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) for summarized effects and I² statistics of heterogeneity were extracted from individual studies or reanalyzed using a random-effects model. Of the 50 included studies, pooled effects of PNSs on blood pressure, lipid profiles, and glycemic control were reported in 16, 25, and 14 articles, respectively. The findings appeared to be highly heterogeneous among individual trials of included systematic reviews and meta-analyses. Ginger (WMD = -6.36 mmHg, 95% CI = -11.27, -1.46) and Hibiscus sabdariffa (WMD = -7.58 mmHg, 95% CI = -9.69, -5.46) were associated with lowered systolic blood pressure, whereas Aloe vera, Nigella sativa, and spirulina were associated with beneficial effects on both lipid profiles and glycemic control. In summary, this umbrella review has provided up-to-date evidence for the effect of PNSs on biomarkers related to hypertension, dyslipidemia, and diabetes. The results must be interpreted with caution due to potential heterogeneity.

Interaction of silymarin components and their sulfate metabolites with human serum albumin and cytochrome P450 (2C9, 2C19, 2D6, and 3A4) enzymes

Silymarin is a mixture of flavonolignans isolated from the fruit of milk thistle (Silybum marianum (L.) Gaertner). Milk thistle extract is the active ingredient of several medications and dietary supplements to treat liver injury/diseases. After the oral administration, flavonolignans are extensively biotransformed, resulting in the formation of sulfate and/or glucuronide metabolites. Previous studies demonstrated that silymarin components form stable complexes with serum albumin and can inhibit certain cytochrome P450 (CYP) enzymes. Nevertheless, in most of these investigations, silybin was tested; while no or only limited information is available regarding other silymarin components and metabolites. In this study, the interactions of five silymarin components (silybin A, silybin B, isosilybin A, silychristin, and 2,3-dehydrosilychristin) and their sulfate metabolites were examined with human serum albumin and CYP (2C9, 2C19, 2D6, and 3A4) enzymes. Our results demonstrate that each compound tested forms stable complexes with albumin, and certain silymarin components/metabolites can inhibit CYP enzymes. Most of the sulfate conjugates were less potent inhibitors of CYP enzymes, but 2,3-dehydrosilychristin-19-O-sulfate showed the strongest inhibitory effect on CYP3A4. Based on these observations, the simultaneous administration of high dose silymarin with medications should be carefully considered, because milk thistle flavonolignans and/or their sulfate metabolites may interfere with drug therapy.

The Effects of Magnesium Supplementation on Lipid Profile Among Type 2 Diabetes Patients: a Systematic Review and Meta-analysis of Randomized Controlled Trials

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effects of magnesium (Mg) supplementation on the lipid profile in type 2 diabetes (T2DM) patients. Web of Science, Scopus, PubMed, and Embase databases were searched to infinity until 30 January 2020. Weighted mean differences (WMD) were pooled using a random-effects model. Heterogeneity, sensitivity analysis, and publication bias were reported using standard methods. The pooled analysis of 12 randomized controlled trial s indicated that Mg administration led to significant reduction of serum low-density lipoprotein (LDL) levels (p = 0.006). However, our results revealed that Mg supplementation did not have any effect on triglycerides (TG), total cholesterol (TC), and high-density lipoprotein (HDL) serum concentrations among T2DM patients in comparison with the control group. Subgroup analysis based on duration of study suggested that more than 12 weeks of Mg supplementation significantly decreased the serum TC levels (p = 0.002). Subgroup analysis comparing the dose of intervention indicated that Mg supplementation less than 300 mg significantly decreased the serum LDL concentrations (p < 0.001), while more than 300 mg of Mg supplementation significantly increased the serum HDL levels (p = 0.026). In a subgroup analysis comparing the type of intervention, it displayed that inorganic Mg supplementation decreased the LDL (p < 0.001) and TC (p = 0.003) levels, while organic Mg supplementation showed no difference. Mg supplementation has a beneficial effect on lowering LDL level in T2DM patients. However, we have to note that any research performed so far is not sufficient for making robust guidelines to use Mg supplementation in clinical practice.

The therapeutic effects of silymarin for patients with glucose/lipid metabolic dysfunction: A meta-analysis

BACKGROUND

To comprehensively evaluate the treatment efficacy and safety of silymarin for patients with glucose/lipid metabolic dysfunction using a meta-analysis.

METHODS

A systematic literature search in PubMed, EMBASE and Cochrane Library databases was performed up to October 1, 2019. STATA 13.0 software was used to estimate pooled standardized mean difference (SMD) and 95% confidence interval (95% CI).

RESULTS

Sixteen studies involving 1358 patients were identified. Overall meta-analysis showed that compared with control, silymarin significantly reduced levels of fasting blood glucose (SMD: -1.27, 95% CI = [-1.78, -0.76]; P < .001), homeostatic model assessment for insulin resistance (SMD: -0.41, 95% CI = [-0.70, -0.12]; P = .005), hemoglobin A1c (SMD: -1.88, 95% CI = [-2.57, -1.20]; P < .001), total cholesterol (SMD: -1.13, 95% CI = [-1.82, -0.77]; P < .001), triglyceride (SMD: -0.37, 95% CI = [-0.69, -0.05]; P = .025), low-density lipoprotein-cholesterol (SMD: -1.30, 95% CI = [-1.93, -0.67]; P < .001), C-reactive protein (SMD: -0.63, 95% CI = [-1.01, -0.27]; P = .001), and increased high-density lipoprotein-cholesterol (SMD: 0.17, 95% CI = [0.05, 0.29]; P = .005), but had no impacts on function indicators of liver and kidney (alanine transaminase, aspartate aminotransferase, creatinine phosphokinase, creatinine) and the complication rate. Subgroup analyses indicated that insulin (which was negative in overall analysis) was significantly decreased in patients undergoing silymarin monotherapy (SMD: -2.03, 95% CI = [-3.03, -1.04]; P = .044) for more than 3 months (SMD: -0.01, 95% CI = [-0.25, -0.24]; P = .035).

CONCLUSION

Supplementation of silymarin may be effective and safe for the management of diabetes mellitus and hyperlipidemia.

Identification of UDP-glucuronosyltransferases involved in the metabolism of silymarin flavonolignans

Silybum marianum (milk thistle) is a medicinal plant used for producing the hepatoprotective remedy silymarin. Its main bioactive constituents, including silybin and related flavonolignans, can be metabolized directly by phase II conjugation reactions. This study was designed to identify UDP-glucuronosyltransferases (UGTs) involved in the glucuronidation of six silymarin flavonolignans, namely silybin A, silybin B, isosilybin A, isosilybin B, silychristin, and silydianin. UHPLC-MS analyses showed that all of the tested compounds, both individually and in silymarin, were glucuronidated by human liver microsomes, and that glucuronidation was the main metabolic transformation in human hepatocytes. Further, each compound was glucuronidated by multiple recombinant human UGT enzymes. UGTs 1A1, 1A3, 1A8 and 1A9 were able to conjugate all of the tested flavonolignans, and some of them were also metabolized by UGTs 1A6, 1A7, 1A10, 2B7 and 2B15. In contrast, no glucuronides were produced by UGTs 1A4, 2B4, 2B10 and 2B17. With silymarin, we found that UGT1A1 and, to a lesser extent UGT1A9, were primarily responsible for the glucuronidation of the flavonolignan constituents. It is concluded that the metabolism of silymarin flavonolignans may involve multiple UGT enzymes, of which UGT1A1 appears to play the major role in the glucuronidation. These results may be relevant for future research on the metabolism of flavonolignans in humans.

Effects of cardamom supplementation on lipid profile: A systematic review and meta-analysis of randomized controlled clinical trials

Cardiovascular disease is a highly prevalent issue worldwide and one of its main manifestations, dyslipidemia, needs more attention. Recent studies have suggested that cardamom has favorable effects beyond lipid lowering, but the result are contradictory. Our objective was to conduct a systematic review and meta-analysis on randomized controlled trials (RCTs) that assessed the effect of cardamom on lipids. The search included PubMed, Scopus, ISI Web of Science, Google Scholar, and the Cochrane library (up to March, 2019) to identify RCTs investigating the effects of cardamom supplementation on serum lipid parameters. Weighted mean differences (WMDs) were pooled using a random-effect model. Meta-analysis of data from five eligible RCTs showed that cardamom supplementation did not significantly change the concentrations of total cholesterol (WMD: -6.11 mg/dl, 95% CI [-13.06, 0.83], I² = 0.0%), low-density lipoprotein cholesterol (WMD: -4.31 mg/dl, 95% CI [-9.75, 1.13], I² = 0.0%), or high-density lipoprotein cholesterol (WMD: 1.75 mg/dl, 95% CI [-1.95 to 5.46], I² = 71.4%). However, a significant reduction was observed in serum triglyceride (TG; WMD: -20.55 mg/dl, 95% CI [-32.48, -8.63], I² = 0.0%) levels after cardamom supplementation. Cardamom might be able to change TG, but for confirming the results, more studies exclusively on dyslipidemia patients and considering the intake of lipid lowering agents as exclusion criteria are necessary.