Effect of Silybin on Lipid Profile in Hypercholesterolaemic Rats

Bioactive Flavonoids in Protecting Against Endothelial Dysfunction and Atherosclerosis

Atherosclerosis is a common cardiovascular disease closely associated with factors such as hyperlipidaemia and chronic inflammation. Among them, endothelial dysfunction serves as a major predisposing factor. Vascular endothelial dysfunction is manifested by impaired endothelium-dependent vasodilation, enhanced oxidative stress, chronic inflammation, leukocyte adhesion and hyperpermeability, endothelial senescence, and endothelial-mesenchymal transition (EndoMT). Flavonoids are known for their antioxidant activity, eliminating oxidative stress induced by reactive oxygen species (ROS), thereby preventing the oxidation of low-density lipoprotein (LDL) cholesterol, reducing platelet aggregation, alleviating ischemic damage, and improving vascular function. Flavonoids have also been shown to possess anti-inflammatory activity and to protect the cardiovascular system. This review focuses on the protective effects of these naturally-occuring bioactive flavonoids against the initiation and progression of atherosclerosis through their effects on endothelial cells including, but not limited to, their antioxidant, anti-inflammatory, anti-thrombotic, and lipid-lowering properties. However, more clinical evidences are still needed to determine the exact role and optimal dosage of these compounds in the treatment of atherosclerosis.

Impact of Berberine or Berberine Combination Products on Lipoprotein, Triglyceride and Biological Safety Marker Concentrations in Patients with Hyperlipidemia: A Systematic Review and Meta-Analysis

Monoclonal antibody Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) inhibitors reduce total cholesterol (TC), low density lipoproteins (LDL), high density lipoproteins (HDL), and triglycerides (TG). We assessed the ability of berberine, a natural PCSK9 inhibitor, to reduce lipid concentrations either alone or combined with other nutraceuticals. We searched PubMed, Scopus and EMBASE from inception to September 30th, 2022 for randomized controlled trials (RCTs) assessing 8-18 wk of berberine therapy on. A total of 41 RCTs with 4,838 patients met our inclusion criteria. Berberine containing products significantly reduced TC (MD -17.42 mg/dL [95%CI: -22.91 to -11.93]), LDL (MD -14.98 mg/dL [95%CI: -20.67 to -9.28]), and TG (MD -18.67 mg/dL [95%CI: -25.82 to -11.51]) while raising HDL (MD 1.97 mg/dL [95%CI: 1.16 to 2.78]) versus control (I2 > 72% for all analyses). Products with berberine alone had less robust effects on TC (MD -12.08 mg/dL [95%CI: -21.79 to -2.37]), LDL (MD -9.26 mg/dL [95%CI: -20.31 to 1.78]), and HDL (MD 1.38 mg/dL [95%CI: -1.27 to 4.03]) but TG effects were similar (MD -17.40 mg/dL [95%CI: -32.57 to -2.23]). Berberine along with red yeast rice reduced TC (MD -19.62 mg/dL [95%CI: -28.56 to -10.68]) and LDL (MD -18.79 mg/dL [95%CI: -28.03 to -9.54]) as did combination therapy with Silybum maranium for TC (MD -31.81 mg/dL [95%CI: -59.88 to -3.73]) and LDL (MD -30.82 mg/dL [95%CI: -56.48 to -5.16]). Berberine, alone or with other nutraceuticals, can provide a modest positive impact on lipid concentrations.

Trained immunity in monocyte/macrophage: Novel mechanism of phytochemicals in the treatment of atherosclerotic cardiovascular disease

Atherosclerosis (AS) is the pathology of atherosclerotic cardiovascular diseases (ASCVD), characterized by persistent chronic inflammation in the vessel wall, in which monocytes/macrophages play a key role. It has been reported that innate immune system cells can assume a persistent proinflammatory state after short stimulation with endogenous atherogenic stimuli. The pathogenesis of AS can be influenced by this persistent hyperactivation of the innate immune system, which is termed trained immunity. Trained immunity has also been implicated as a key pathological mechanism, leading to persistent chronic inflammation in AS. Trained immunity is mediated via epigenetic and metabolic reprogramming and occurs in mature innate immune cells and their bone marrow progenitors. Natural products are promising candidates for novel pharmacological agents that can be used to prevent or treat cardiovascular diseases (CVD). A variety of natural products and agents exhibiting antiatherosclerotic abilities have been reported to potentially interfere with the pharmacological targets of trained immunity. This review describes in as much detail as possible the mechanisms involved in trained immunity and how phytochemicals of this process inhibit AS by affecting trained monocytes/macrophages.

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.

Effect of Silibinin on Dyslipidemia and Glycemic Alteration Associated with Polycystic Ovarian Syndrome: An Experimental Study on Rats

PURPOSE

Females with polycystic ovary syndrome (PCOS) are found to have hormonal and metabolic alterations. This study investigated the efficacy of the flavonolignan silibinin in restoring the metabolic alterations associated with letrozole-induced PCOS in rats.

METHODS

The study allocated 42 albino rats into two groups. The first group was a normal control group (n=12) in which only the vehicle was given. The second group, the PCOS group (n=30), received letrozole (1 mg/kg/day) orally for 21 days. On day 21, six animals from the first group and six animals from the second group were sacrificed to confirm the development of PCOS, and the rest of the animals (n=24) in the second group were distributed equally into four groups: the PCOS group received vehicle, the metformin (MET) group received 300 mg/kg metformin orally, and the low-dose silibinin (LD-100) and high-dose silibinin (HD-200) groups received 100 and 200 mg/kg silibinin intraperitoneally, respectively. Blockade of the estrus cycle in the diestrus phase, hyperglycemia, and body weight elevation were related to a positive PCOS induction. An oral glucose tolerance test (OGTT) was also carried out for all animals on day 21 and on the last day of the experiment (day 40) to investigate the effect of silibinin on insulin resistance. The rats' lipid profile, insulin level, estrus cycle patterns, body weight, and weights of the ovaries and uterus were also measured on day 40.

RESULTS

A 19-day silibinin treatment led to the restoration of regular estrus cyclicity, reduced the glucose spike in OGTT analysis, and alleviated insulin resistance in PCOS rats. There was a statistically non-significant decrement in insulin level and lipid profile in the treatment groups.

CONCLUSION

Silibinin flavonolignan ameliorated some metabolic and reproductive alterations associated with PCOS. This could be related to the decreased insulin resistance, and antiandrogenic and phytoestrogenic activity of silibinin. Further study with longer term therapy is recommended to clarify more potential effects of silibinin and its mechanism of action in PCOS.

Liver Protection Mechanism and Absorption Promotion Technology of Silybin Based on Intelligent Medical Analysis

With the continuous popularization of smart medicine, the protective effect of silibinin in the liver has attracted much attention. This study mainly explores the liver protection mechanism and absorption promotion technology of silybin based on intelligent medical analysis. Refining of silibinin: accurately weigh 1.0 g of silibinin in a three-necked flask; gradually add 50 mL of anhydrous methanol, reflux and filter the precipitated solid; and weigh it after drying. ICR male mice were taken as experimental subjects and randomly divided into groups of 10 each. The mice in the normal group and the model group were given intragastrically with 0.5% CMC-Na solution; the mice in the silibinin group were given intragastrically with SB/CMC-Na suspension; the mice in the remaining groups were given low, medium, and high-dose suspensions to their stomachs, and silibinin 23 acylate/CMC-Na suspension was administered at a dose of 10 mL/kg for 7 consecutive days. After that, the mice were fasted for 12 hours. After 6 hours of fasting (18 hours after modeling), the blood cells from their orbits were taken, placed in a 37°C water bath for 30 minutes, and centrifuged at 4000 rpm for 10 minutes, and then the serum was taken; the activity equivalent of AST and ALT in serum was measured; serum determination Medium AST and ALT vitality. The mice were killed by decapitation, fresh liver tissue was immediately collected, and part of it was frozen in liquid nitrogen for the RT-PCR test. The hepatocyte expansion and death were observed using a transmission electron microscope, and the oncosis index (OI) was calculated. Another part of the liver tissue was fixed in 4% paraformaldehyde solution, embedded in paraffin, dehydrated, and sliced at 4 μm. Some sections were stained with conventional HE, and the pathological changes of liver cells were observed under light microscope; some sections were subjected to immunohistochemistry. Only one mouse died when 240 mg/kg of silibinin was given 10 minutes after the model was modeled. However, when 240 mg/kg silibinin was given to the mice 20 minutes after modeling, the mortality rate of the mice rose to 50%, and the therapeutic effect was significantly weakened. This research is helpful to advance the research of silybin in liver protection.

Hypoglycemic and hypolipidemic activity of combined milk thistle and fenugreek seeds in alloxan-induced diabetic albino rats

BACKGROUND AND AIM

Despite the availability of antidiabetic drugs, they are not free from associated adverse side effects. This study aimed to evaluate the hypoglycemic and hypolipidemic effects of oral administration of seeds from two medicinal plants: (1) Milk thistle and (2) fenugreek.

MATERIALS AND METHODS

Plant seeds were washed in distilled water and ground with a coffee grinder. Alloxan was used to induce diabetes in 20 male albino rats. Diabetic rats were randomly divided into two groups: (1) Group 1 (n=10), diabetic rats fed with 0.5 g/kg milk thistle and 2 g/kg fenugreek seeds per day and (2) Group 2 (n=10), diabetic rats fed standard rodent food for 4 weeks.

RESULTS

Oral administration of milk thistle and fenugreek seeds for 2 weeks resulted in significant improvement in body weight, blood glucose, glycosylated hemoglobin (HbA1c), cholesterol, and triglyceride levels in alloxan-induced diabetic rats. After 4 weeks, this ameliorative effect was significantly elevated with respect to blood glucose (155.00±9.70 mg/dL vs. 427.50±5.70 mg/dL; p<0.001), HbA1c (5.5±0.19% vs. 13.65±1.77%; p<0.001), cholesterol (281.50±10.95 mg/dL vs. 334.30±6.80 mg/dL; p<0.001), triglyceride (239.60±6.87 mg/dL vs. 284.20±9.95 mg/dL; p<0.01), and body weight (265.30±8.10 g vs. 207.40±11.4 g; p<0.01) as compared with non-treated diabetic rats.

CONCLUSION

Milk thistle and fenugreek seeds possess hypoglycemic and hypolipidemic properties and could be used as natural compounds that are suitable as parent compounds for the development of new antidiabetic drugs.

YangXue QingNao Wan and Silibinin Capsules, the Two Chinese Medicines, Attenuate Cognitive Impairment in Aged LDLR (+/-) Golden Syrian Hamsters Involving Protection of Blood Brain Barrier

The purpose of the study was to explore the effect and the underlying mechanism of YangXue QingNao Wan (YXQNW) and Silibinin Capsules (SC), the two Chinese medicines, on cognitive impairment in older people with familial hyperlipidaemia. Fourteen month-old female LDLR (+/-) golden Syrian hamsters were used with their wild type as control. YXQNW (0.5 g/kg/day), SC (0.1 g/kg/day), or YXQNW (0.5 g/kg/day) + SC (0.1 g/kg/day) were administrated orally for 30 days. To assess the effects of the two drugs on plasma lipid content and cognitive ability, plasma TC, TG, LDL-C, and HDL-C were measured, and Y maze task was carried out both before and after administration. After administering of the drugs for 30 days, to evaluate the effect of the two drugs on disturbed blood flow caused by hyperlipidemia, the cerebral blood flow (CBF) was measured. To assess blood-brain barrier integrity, albumin leakage in middle cerebral artery (MCA) area was determined. To evaluate the effect of the drugs on impaired microvessels, the number and morphology of microvessels were assessed in hippocampus area. To further evaluate the ultrastructure of microvessels in hippocampus, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were carried out. To assess the profiles of claudin-5 and occludin in hippocampus, we performed immunofluorescence. Finally, to assess the expression of claudin-5, JAM-1, occludin and ZO-1 in hippocampus, western blot was carried out. The results showed that YXQNW, SC, and YXQNW + SC improved cognitive impairment of aged LDLR (+/-) golden Syrian hamsters without lowering plasma TC and LDL-C. YXQNW, SC, and YXQNW + SC attenuated albumin leakage in MCA area and neuronal damage in hippocampus, concomitant with an increase in CBF, a decrease of perivascular edema and an up-regulated expression of claudin-5, occludin and ZO-1. In conclusion, YXQNW, SC, and YXQNW + SC are able to improve cognitive ability in aged LDLR (+/-) golden Syrian hamsters via mechanisms involving maintaining blood-brain barrier integrity. These findings provide evidence suggesting YXQNW or SC as a potential regime to counteract the cognitive impairment caused by familial hypercholesterolemia.