In vivo recovery effect of silibinin treatment on streptozotocin-induced diabetic mice is associated with the modulations of sirt-1 expression and autophagy in pancreatic β-cell

Improper adjustments of autophagy and silent information regulator 1 (Sirt-1) expression were reported to be closely associated with metabolic disorders. In this study, we examined the roles of Sirt-1 and autophagy in streptozotocin-induced diabetes mellitus, assessed the relationship between autophagy and Sirt-1, and investigated the protective mechanism of silibinin. Diabetes was induced in 6-week-old mice by intravenous injection of streptozotocin (150 mg/kg/day, for 2 weeks). In the treatment groups, silibinin (50 mg/kg/day, intramuscular injection, for 8 weeks) or inhibitors (50 mg/kg/day, subcutaneous injection, for 8 weeks) were given. Diabetic control animals received vehicle for the same time. Compared with diabetic controls, silibinin or autophagy inhibitor, 3-methyladenine, treated mice showed decreased levels of glycosylated hemoglobin A1C (P < 0.01), serum triglyceride (P < 0.01), cholesterol (P < 0.01), blood glucose (P < 0.05), autophagy (P < 0.05), and apoptosis ratio (P < 0.05) of pancreatic β-cells. Systemic administration of silibinin reversed streptozotocin-induced downregulation of Sirt-1 expression. Sirt-1 may play a role in regulating the physiological level of autophagy and is associated with loss of pancreatic β-cells and metabolic biochemical disorders. Through promoting Sirt-1 expression and recovering autophagy physiologically, silibinin may reverse hyperglycemia and repair damaged pancreatic β-cells.     

Inhibition of urinary bladder cancer cell proliferation by silibinin

Silibinin, a natural compound extracted from milk thistle, has demonstrated antitumor properties in urinary bladder cancer cells; however, the role of TP53 gene in these effects is unclear. In order to better understand the molecular and antiproliferative mechanisms of this compound, urinary bladder cancer cells with different TP53 gene status, RT4 (low-grade tumor, wild TP53 gene), 5637 (high-grade tumor, Grade 2, mutated TP53 gene), and T24 (high-grade tumor, Grade 3, mutated TP53 gene) were treated with several concentrations of silibinin (1, 5, 10, 50, 100, and 150 μM). Cytotoxicity, prooxidant effect, morphological changes, cell migration, cell cycle progression, global methylation profile, and relative expression of HOXB3, c-MYC, PLK1, SMAD4, SRC, HAT, HDAC, and RASSF1A genes were evaluated. The silibinin presented cytotoxic and prooxidant effects in the three cell lines. In mutated TP53 cells, significant interference in cell migration and cell cycle arrest at the G2/M phase was observed. Additionally, silibinin induced global DNA hypomethylation in the highest grade tumor cells. For wild-type TP53 cells, a sub-G1 apoptotic population was present. Furthermore, there was modulation of gene expression responsible for cell growth (SMAD and c-MYC), migration (SRC), cell cycle kinetics (PLK1), angiogenesis (HOXB3), and of genes associated with epigenetic events such as DNA acetylation (HAT) and deacetylation (HDAC). In conclusion, the silibinin inhibited the urinary bladder tumor cell proliferation independently of TP53 status; however, cell cycle effects, gene expression changes, and alteration of cell migration are dependent on TP53 status. © 2020 Wiley Periodicals, Inc.     

水飞蓟宾及其同分异构体的抑菌谱及其与抗生素联合抑菌效应探讨

目的探讨水飞蓟宾及同分异构体的体外抗菌谱及水飞蓟宾与临床常用抗生素的联合抑菌效应。方法用微量肉汤稀释法测定水飞蓟宾及同分异构体对临床感染常见细菌的6种标准菌株和6种临床分离菌株(74株)的最低抑菌浓度(MIC)。用平板菌落计数法测定不同质量浓度水飞蓟宾对6种标准菌株的生长抑制曲线。用棋盘微量肉汤稀释法进行水飞蓟宾与临床常用抗生素的联合药敏试验,计算联合抑菌指数(FIC),判定水飞蓟宾与抗生素的联合抑菌效应。结果水飞蓟宾对表皮葡萄球菌、金黄色葡萄球菌、粪肠球菌和屎肠球菌标准菌株的MIC为50~400μg/m L,对大肠埃希菌和铜绿假单胞菌标准菌株的MIC均400μg/m L;对表皮葡萄葡萄球菌临床分离菌株的MIC分别为100、200、400、400μg/m L,对金黄色葡萄球菌、粪肠球菌和屎肠球菌临床分离菌株的MIC分别为400、400μg/m L;对大肠埃希菌和铜绿假单胞菌临床分离菌株的MIC均400μg/m L。水飞蓟宾其他同分异构体对6种标准菌株的MIC为≥400μg/m L。水飞蓟宾对表皮葡萄球菌、金黄色葡萄球菌、粪肠球菌和屎肠球菌标准菌株的生长曲线都有明显抑制作用,抑制效果随药物质量浓度增加而增加,对大肠埃希菌和铜绿假单胞菌标准菌株的生长曲线无影响。水飞蓟宾与青霉素/红霉素联用对革兰阳性试验菌的FIC以0.5FIC≤1和1FIC≤2为主,水飞蓟宾与环丙沙星或庆大霉素联用对革兰阴性试验菌的FIC以FIC2或1FIC≤2为主。结论水飞蓟宾对革兰阳性菌有较好的抑菌活性,其中对表皮葡萄球菌抑菌活性最强。水飞蓟宾的抑菌活性明显高于其他同分异构体。水飞蓟宾与青霉素/红霉素联用主要为相加和无关作用,与环丙沙星或庆大霉素联用主要为拮抗或无关作用。     

Silibinin affects the pharmacokinetics of methadone in rats

The aim of the present study was to investigate the pharmacokinetic effect of silibinin on methadone in rats. Twenty‐four male Sprague–Dawley rats were randomly divided into 4 groups: control group, single dose of 100 mg/kg group, multiple doses of 100 mg/kg group, and multiple doses of 30 mg/kg group. A single dose of 6 mg/kg methadone was administrated to rats orally without or with silibinin. Plasma samples were collected via tail vein at different time points and concentrations of methadone and its metabolite, 2‐ethylidene‐1,5‐dimethyl‐3,3‐diphenylpyrrolidine (EDDP), were determined by ultra performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). Compared with the control group (without silibinin), both 30 and 100 mg/kg silibinin significantly increased the C_max of methadone, but only 100 mg/kg silibinin significantly increased the AUC_(0‐t) of methadone and decreased its clearance. Pharmacokinetics parameters of EDDP were not altered by 30 mg/kg silibinin; its T_max was decreased by 100 mg/kg silibinin and the C_max was increased by single dose of 100 mg/kg silibinin. It is concluded that silibinin significantly altered the pharmacokinetics of methadone in rats by increasing the exposure of methadone. Further investigations in human should be conducted. Therapeutic drug monitoring of methadone in individuals undergoing methadone maintenance therapy is recommended when silibinin is concomitant.     

水飞蓟宾对内毒素血症心肌损伤的保护作用及机制

摘要：目的探究水飞蓟宾（SIL）对小鼠内毒素血症心肌损伤的保护作用和分子机制。方法24只C57BL/6小鼠分为对照（Control）组、SIL组、LPS组、LPS+SIL组,每组6只。通过腹腔注射脂多糖（LPS,10 mg/kg）制备内毒素血症心肌损伤小鼠模型。LPS注射前3 d,SIL组和LPS+SIL组每日通过灌胃方式给予SIL（100 mg/kg）,共给药3次;Control组和LPS组每日通过灌胃方式给予等量（0.2 mL）生理盐水,共灌胃3次。LPS注射6 h后超声检测各组小鼠心脏收缩功能;ELISA检测血清IL-1β和TNF-α表达水平;DHE染色观察各组小鼠心肌组织内活性氧（ROS）产量;TUNEL染色检测心肌凋亡率;Western blot检测凋亡相关蛋白Bax、Bcl-2、Caspase 3和NOX2表达。结果与Control组相比,LPS组小鼠左心室射血分数、左心室短轴缩短率和Bcl-2表达量明显降低,而ROS产量、NOX2、Bax、Caspase 3、IL-1β与TNF-α表达量以及心肌凋亡率明显增加（P＜0.05）。与LPS组相比,LPS+SIL组经水飞蓟宾预处理后可明显改善LPS引起的上述改变（P＜0.05）。与Control组相比,单纯给予SIL干预对上述指标的变化无明显影响（P＞0.05）。结论水飞蓟宾可有效缓解内毒素血症心肌损伤,其作用可能与抑制氧化应激、炎症反应和抗凋亡有关。     

Inhibitory effect of silibinin on ligand binding to erbB1 and associated mitogenic signaling, growth, and DNA synthesis in advanced human prostate carcinoma cells

We recently showed the inhibitory effect of a flavonoid antioxidant, silymarin, on erbB1-Shc activation in prostate cancer (PCA) DU145 cells. In the present study, we performed more detailed mechanistic and molecular modeling studies with pure silibinin to assess and define its effect on membrane signaling related to erbB1 activation in human PCA LNCaP and DU145 cells. Studies also were performed to establish the biologic responses toward extracellular signal-regulated protein kinase 1/2 (ERK1/2) activation, cell growth, and DNA synthesis. Treatment of serum-starved cells with various doses of silibinin for 2 h followed by (125)I-epidermal growth factor (EGF) showed 30-75% inhibition in ligand binding and 55-95% inhibition in its internalization in LNCaP cells and 20-64% and 12-27% inhibition in these two events in DU145 cells. Time-response studies showed similar effects. In further studies, treatment of serum-starved cultures with silibinin followed by EGF showed strong inhibitory effects on membrane and cytoplasmic signaling molecules. In the case of erbB1 activation, silibinin showed a 58-75% decrease in LNCaP and a 40-100% decrease in DU145 cells at 50, 75, and 100-microg/mL doses. Inhibitory effects of silibinin also were evident on ERK1/2 activation (20-80% inhibition) in both cell lines. Treatment of serum-starved cultures with silibinin resulted in 20-40% and 30-55% inhibition of LNCaP and DU145 cell growth, respectively, at similar doses after 1-3 d of treatment, and 10-50% cell death in both cell lines. Under 10% serum conditions, identical silibinin treatments resulted in 20-65% inhibition of cell growth in LNCaP and DU145 cells but did not cause any cell death. Similar doses of silibinin treatments for 24 h also resulted in 25-60%, 35-40%, and 36-50% inhibition of DNA synthesis when cells were cultured in 10% serum, totally serum starved, and serum starved plus stimulated with EGF, respectively. Molecular modeling of silibinin showed that it is a highly lipophilic compound, suggesting that it interacts with lipid-rich plasma membrane, including binding with erbB1, thereby competing with the EGF-erbB1 interaction. Because the ligand-erbB1 autocrine-loop is causally involved in advanced and androgen-independent PCA, the observed effects of silibinin and its strong lipophilic nature could be useful in developing this agent for the prevention and therapy of PCA.     

水飞蓟宾对阿尔茨海默病模型大鼠学习记忆功能及对神经细胞内活性氧的影响

目的探讨水飞蓟宾对阿尔茨海默病(AD)大鼠行为的改善作用及对神经细胞内自由基的清除情况。方法大鼠60只,采用皮下注射东莨菪碱致AD模型,随机分为模型组、空白对照组、水飞蓟宾高中低剂量组及阳性对照多奈哌齐组,用Morris水迷宫法,检测大鼠的学习记忆能力。另外采用过氧化试剂诱导人神经母细胞瘤细胞(SH-SY5Y)过氧化损伤通过流式细胞仪检测水飞蓟宾对活性氧自由基的清除能力。结果模型组与空白对照组比学习记忆能力显著下降,治疗组与模型组比学习记忆能力得到显著改善,同时体外实验证实水飞蓟宾能显著降低细胞内的自由基水平。结论水飞蓟宾对AD有较好的改善作用,其机制可能与其抗自由基活性有关。     

Silibinin synergizes with mitoxantrone to inhibit cell growth and induce apoptosis in human prostate cancer cells

The purpose of these experiments was to assess the synergistic activity of silibinin with chemotherapy agents in clinical use against prostate cancer. Silybin-phytosome, a commercially available formulation containing silibinin, has recently been studied in a phase I clinical trial. The silibinin doses used in the present study are clinically achievable based on the preliminary phase I data. DU145, PC-3 and LNCaP prostate cancer cells were seeded in 96-well plates in triplicate. Twenty-four hours later, silibinin (10, 20 and 40 microM) and either mitoxantrone or docetaxel were added to the designated wells. Seventy-two hours post-treatment, cell viability was determined with a tetrazolium-based assay. The combination index (CI) for determination of a synergistic effect was calculated, with values of <0.9 indicating synergy and values >1.1 antagonism. Apoptosis was also assessed using a luminescent assay after 72 hr of treatment with media alone, silibinin, mitoxantrone, or silibinin plus mitoxantrone. Silibinin showed a synergistic effect with mitoxantrone, as measured by reduction in cell viability. The CI values ranged from 0.413 to 2.650 for the combination of silibinin and mitoxantrone; in contrast, treatment with docetaxel and silibinin showed little or no synergy, with CI values of 0.898-4.469. In concordance with these findings, the addition of silibinin increased the level of apoptosis compared to mitoxantrone alone, particularly in the PC-3 cells. The combination of silibinin and mitoxantrone exhibits a pattern of synergy in reducing cell viability with increased apoptosis. These data are important in the planning of future clinical applications of silibinin.     

Silibinin prevents dopaminergic neuronal loss in a mouse model of Parkinson's disease via mitochondrial stabilization

Parkinson's disease (PD) is a progressive neurodegenerative disease characterized by the selective loss of dopaminergic neurons in the nigrostriatal pathway. The lipophile 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) can cross the blood–brain barrier and is subsequently metabolized into toxic1‐methyl‐4‐phenylpyridine (MPP⁺), which causes mitochondrial dysfunction and the selective cell death of dopaminergic neurons. The present article reports the neuroprotective effects of silibinin in a murine MPTP model of PD. The flavonoid silibinin is the major active constituent of silymarin, an extract of milk thistle seeds, and is known to have hepatoprotective, anticancer, antioxidative, and neuroprotective effects. In the present study, silibinin effectively attenuated motor deficit and dopaminergic neuronal loss caused by MPTP. Furthermore, in vitro study confirmed that silibinin protects primary cultured neurons against MPP⁺‐induced cell death and mitochondrial membrane disruption. The findings of the present study indicate that silibinin has neuroprotective effects in MPTP‐induced models of PD rather than antioxidative or anti‐inflammatory effects and that the neuroprotection afforded might be mediated by the stabilization of mitochondrial membrane potential. Furthermore, these findings suggest that silibinin protects mitochondria in MPTP‐induced PD models and that it offers a starting point for the development of treatments that ameliorate the symptoms of PD. © 2015 Wiley Periodicals, Inc.