Batch solvent extraction of flavanolignans from milk thistle (Silybum marianum L. Gaertner)

Mitigation of intrahepatic cholestasis induced by 17α-ethinylestradiol via nanoformulation of Silybum marianum L

BACKGROUND

Cholestasis is an important predisposing factor for hepatocyte damage, liver fibrosis, primary biliary cirrhosis, and even liver failure. Silybum marianum L. (SM) plant is used in teas or eaten in some countries due to its antioxidant and hepatoprotective properties. Because of its low and poor oral bioavailability, so we improve the therapeutic activity of Silybum marianum L. extract (SM) by studying the potential effects of nanoformulation of Silybum marianium L. extract (nano-SM) on 17α-ethinylestradiol (EE)-induced intrahepatic cholestasis.

METHODS

Thirty female Sprague-Dawley rats were divided into 5 groups (6 rats/group). Group I: Rats were received the treatment vehicle and served as normal group. Group II:Rats were injected daily with EE (10 mg/kg) for five successive days. Group III-V: Rats were injected daily with EE (10 mg/kg) and treated with either Ursodeoxycholic acid (UDCA) (40 mg/kg), SM (100 mg/kg) and nano-SM (100 mg/kg) orally once/day throughout the trialfor five successive days, respectively.

RESULTS

Nano-SM greatly dampened the increase in serum levels of total and direct bilirubin, alanine aminotransaminase, aspartate aminotransaminase, and alkaline phosphatase caused by EE. Furthermore, nano-SM increased the hepatic contents of reduced glutathione (GSH) and catalase (CAT) and also upregulated the relative hepatic gene expressions of Rho-kinase (ROCK-1), myosin light chain kinase (MLCK), and myosin phosphatase target subunit (MYPT1) compared to the EE-induced group. Administration of nano-SM reduced hepatic lipid peroxidation and downregulated the relative hepatic expressions of the nuclear factor-kappa B (NF-ҡB) and interleukin-1β (IL-1β). In addition, nano-SM improved the histopathological changes induced by EE.

CONCLUSION

Nano-SM possessed a superior effect over SM, which can be considered an effective protective modality against EE-induced cholestatic liver injury through its antioxidant, anti-inflammatory activities, and enhancing bile acid (BA) efflux.

Dihydroquercetin Supplementation Improved Hepatic Lipid Dysmetabolism Mediated by Gut Microbiota in High-Fat Diet (HFD)-Fed Mice

Dihydroquercetin (DHQ) is a natural flavonoid with multiple bioactivities, including hepatoprotective effects. This study aimed to investigate whether DHQ improved lipid dysmetabolism in the body, especially in the liver, and whether there is a relationship between hepatic metabolism and altered gut flora in high-fat diet (HFD)-induced mice. HFD-induced mice were given 50 mg/kg body weight DHQ intragastrically for 10 weeks. The data showed that DHQ reduced body weight, the weight of the liver and white adipose tissue as well as serum leptin, LPS, triglyceride and cholesterol levels. RNA-seq results indicated that DHQ down-regulated lipogenesis-related genes and up-regulated fatty acid oxidation-related genes, including MOGAT1 and CPT1A. Furthermore, DHQ had a tendency to decrease hepatic cholesterol contents by reducing the mRNA levels of cholesterol synthesis genes such as FDPS and HMGCS1. 16S rRNA sequencing analysis indicated that DHQ significantly decreased the richness of Lactococcus, Lachnoclostridium, and Eubacterium_xylanophilum_group. Correlation analysis further demonstrated that these bacteria, Lactococcus and Eubacterium_xylanophilum_group in particular, had significantly positive correlation with lipid and cholesterol synthesis genes, and negative correlation with fatty acid oxidation genes. In conclusion, DHQ could improve hepatic lipid dysmetabolism potentially by improved gut microbial community, which may be used as an intervention strategy in hepatic metabolism diseases.

Engineering Saccharomyces cerevisiae for the production of dihydroquercetin from naringenin

Background

Dihydroquercetin (DHQ), a powerful bioflavonoid, has a number of health-promoting qualities and shows potential as a treatment for a number of disorders. Dihydroquercetin biosynthesis is a promising solution to meet the rising demand for dihydroquercetin. However, due to the significant accumulation of eriodietyol (ERI), naringenin (NAR), dihydrokaempferol (DHK), and other metabolites, the yield of DHQ biosynthesis is low. As a result, this is the hindrance to the biosynthesis of DHQ.

Results

In this study, we proposed several strategies to enhance the product formation and reduce the metabolites in accumulation. The flavonoid 3′-hydroxylase (F3′H) and cytochrome P450 reductase from different species were co-expressed in S. cerevisiae, and the best strain expressing the P450-reductase enzyme complex (SmF3′H/ScCPR) yielded 435.7 ± 7.6 mg/L of ERI from NAR in the deepwell microplate. The product conversion rate was improved further by mutating the predicted potential ubiquitination sites to improve SmF3′H stability, resulting in a 12.8% increase in titre using the mutant SmF3′H (K290R). Besides, different F3Hs from various sources and promoters were tested for the improved DHQ production, with the best strain producing 381.2 ± 10.7 mg/L of DHQ from 1 g/L of NAR, suggesting the temporal regulation the expression of F3H is important for maximization the function of F3′H and F3H.

Conclusion

This study offers effective strategies for improving DHQ production from NAR and could be used as a reference for related research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12934-022-01937-8.

Effects of Quercetin on the Intestinal Microflora of Freshwater Dark Sleeper Odontobutis potamophila

Flavonoids have antimicrobial and anti-oxidation properties. The effects of the flavonoid quercetin on the intestinal microflora of freshwater dark sleeper Odontobutis potamophila were tested for the first time. Odontobutis potamophila juveniles were treated with quercetin for 21 days at one of three concentrations (2.5, 5.0, or 10.0 mg/L) and compared with a control group that was not treated with quercetin. Quercetin improved the stability of the intestinal flora in O. potamophila and the probiotic bacteria Bacillus spp. and Lactobacillus spp. increased in species abundance after the low concentration quercetin treatments. Furthermore, the abundance of pathogenic bacteria Plesiomonas spp., Aeromonas spp., and Shewanella spp. decreased after the fish had been exposed to quercetin. Activity of hepatic antioxidant enzymes (superoxide dismutase, SOD), (glutathione S-transferase, GST), (glutathione peroxidase, GSH-Px), and (total antioxidant capacity, T-AOC) increased in the livers of O. potamophila treated with quercetin, thereby increasing their hepatic antioxidant capacity and their ability to scavenge free radicals.

In utero di-(2-ethylhexyl) phthalate-induced testicular dysgenesis syndrome in male newborn rats is rescued by taxifolin through reducing oxidative stress

Testicular dysgenesis syndrome in male neonates manifests as cryptorchidism and hypospadias, which can be mimicked by in utero phthalate exposure. However, the underlying phthalate mediated mechanism and therapeutic effects of taxifolin remain unclear. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundantly used phthalate and can induce testicular dysgenesis syndrome in male rats. To explore the mechanism of DEHP mediated effects and develop a therapeutic drug, the natural phytomedicine taxifolin was used. Pregnant Sprague-Dawley female rats were daily gavaged with 750 mg/kg/d DEHP or 10 or 20 mg/kg/d taxifolin alone or in combination from gestational day 14 to 21, and male pup's fetal Leydig cell function, testicular MDA, and antioxidants were examined. DEHP significantly reduced serum testosterone levels of male pups, down-regulated the expression of SCARB1, CYP11A1, HSD3B1, HSD17B3, and INSL3, reduced the cell size of fetal Leydig cells, decreased the levels of antioxidant and related signals (SOD2 and CAT, SIRT1, and PGC1α), induced abnormal aggregation of fetal Leydig cells, and stimulated formation of multinucleated gonocytes and MDA levels. Taxifolin alone (10 and 20 mg/kg/d) did not affect these parameters. However, taxifolin significantly rescued DEHP-induced alterations. DEHP exposure in utero can induce testicular dysgenesis syndrome by altering the oxidative balance and SIRT1/PGC1α levels, and taxifolin is an ideal phytomedicine to prevent phthalate induced testicular dysgenesis syndrome.

Effect of Dihydroquercetin on Energy Metabolism in LPS-Induced Inflammatory Mice

This study investigated the effects and alterations of dihydroquercetin on the growth performance, nutriment metabolism, antioxidant and immune function, and energy substrate utilization in lipopolysaccharide-challenged mice. A total of 0, 50, and 200 mg/kg of dihydroquercetin were intragastrically administered once a day for 21 days. After the pretreatment with dihydroquercetin, each group was subjected to a lipopolysaccharide challenge (except for the control group). After lipopolysaccharide injection, food intake, body weight, metabolic indexes of blood and liver nutrients, blood inflammatory factors, and liver oxidative stress indexes were measured at 6, 12, 24, and 48 h, respectively. Indirect calorimetry analysis was performed by respiratory gas analysis for 48 h to calculate the energy substrate metabolism of carbohydrate, fat, and protein. Urinary nitrogen excretion was measured to evaluate the urinary protein metabolism to calculate the substrate utilization. The results showed that dihydroquercetin pretreatment can significantly increase the weight gain and average food intake and decrease the mortality rate in lipopolysaccharide-induced inflammation mice. Furthermore, dihydroquercetin pretreatment can alleviate the negative effects of lipopolysaccharides by increasing levels of superoxide dismutase and glutathione peroxidase and by decreasing the malondialdehyde and serum inflammatory cytokines (interleukin-1β, nuclear factor κB, and interleukin-6). Dihydroquercetin pretreatment also can relieve nutrient metabolic disorder by increasing blood glucose, serum total protein, and liver glycogen levels and reducing serum and liver triglycerides, serum cholesterol, serum lactate dehydrogenase, and serum urea nitrogen levels. Meanwhile, it increases the relative utilization of carbohydrate, reducing relative utilization of protein and lipid, alleviating the change in energy metabolism pattern from glucose-predominant to lipid-predominant caused by lipopolysaccharide stimulation. In addition, the degree of metabolic pattern transformation depends on the dose of dihydroquercetin supplement. Finally, according to principal component analysis, we found that the inflammation was strongest in the mice at 24 h and was subsequently relieved in the LPS-stimulated group, whereas in the dihydroquercetin-pretreated group, the inflammation was initially relieved. To summarize, dihydroquercetin pretreatment can improve energy metabolism disorder and attenuate the negative effects of lipopolysaccharide challenge in mice from the initial stage of inflammation.

Dihydroquercetin supplement alleviates colonic inflammation potentially through improved gut microbiota community in mice

The purpose of the current study was to investigate the effect of dietary dihydroquercetin (DHQ) supplementation on dextran sodium sulfate (DSS)-induced colitis in mice. Mice were given DHQ supplementation (3 g kg^-1) throughout the study, starting 14 days prior to DSS treatment for 1 week followed by 2 days without DSS. The results showed that dietary DHQ supplementation restored DSS-induced disease activity index (DAI), colon length and histopathology scores of the colon tissue. Additionally, supplementation with DHQ reduced the pro-inflammatory cytokine levels, and enhanced the level of IL-10 in the serum. qPCR results indicated that DHQ supplementation significantly downregulated IL-1β, IL-6, and TNF-α, and upregulated IL-10 gene mRNA expression. Western blot results proved that DHQ supplementation upregulated ZO-1 and occludin levels. Using amplicon sequencing technology, 16S rRNA sequencing results showed that DHQ supplementation increased the fecal Firmicutes/Bacteroidetes ratio and the relative abundance of Lactobacillus and Dubosiella, and decreased the relative abundance of Bacteroidetes. Additionally, DHQ supplementation restored the decreased fecal acetic acid and butyric acid concentrations in DSS-induced colitis mice. Besides, Spearman's correlation analysis showed that Dubosiella was positively correlated with the butyric acid level and Bacteroidetes was positively correlated with the mRNA expression of IL-1β and IL-6. Both Lactobacillus and Dubosiella showed a negative correlation with the mRNA expression of IL-1β, IL-6, and TNF-α, and Dubosiella was positively correlated with IL-10. In summary, it was found that DHQ supplementation alleviated DSS-induced colitis which may be potentially associated with altered fecal microbiota communities in mice.

Taxifolin as a Promising Ingredient of Cosmetics for Adult Skin

Active substances, effective in the reduction in or delay of skin changes caused by aging occurring in natural compounds, are desirable. Taxifolin (TXF), a flavonoid of strong antioxidant activity found in the plant Stizolophus balsamita (S. balsamita), has been tested for its biological effects on adult human skin. The aim of the study was to investigate the effects of two creams: 3% S. balsamita extract and 3% TXF on the function of adult skin. In total, 97 Caucasian women with clinical signs of skin aging were investigated. The biophysical and biomechanical skin parameters were measured before and after applying the creams, using Colorimeter CL400, Mexameter MX16, Skin-pH-Meter PH900, Skin-Thermometer ST 500, Glossymeter GL200, and Cutiscan SC100. Patch tests were performed with the investigated products to assess their potential irritant properties. The percutaneous penetration of creams was examined with the use of electrospray ionization mass spectrometry (ESI-MS) and confocal Raman spectroscopy. The 3% S. balsamita extract cream reduced hyperpigmentation, erythema, and elevated pH. All the tested preparations were proven to be nonirritant. A higher penetration rate was revealed for the 3% TXF cream than for the 3% S. balsamita extract cream. A total of 3% TXF cream improved skin viscoelasticity. The obtained results suggested that S. balsamita extract and TXF may be considered as ingredients of skincare products for adults.

Exploring the genes involved in biosynthesis of dihydroquercetin and dihydromyricetin in Ampelopsis grossedentata

Dihydroquercetin (DHQ), an extremely low content compound (less than 3%) in plants, is an important component of dietary supplements and used as functional food for its antioxidant activity. Moreover, as downstream metabolites of DHQ, an extremely high content of dihydromyricetin (DHM) is up to 38.5% in Ampelopsis grossedentata. However, the mechanisms involved in the biosynthesis and regulation from DHQ to DHM in A. grossedentata remain unclear. In this study, a comparative transcriptome analysis of A. grossedentata containing extreme amounts of DHM was performed on the Illumina HiSeq 2000 sequencing platform. A total of 167,415,597 high-quality clean reads were obtained and assembled into 100,584 unigenes having an N50 value of 1489. Among these contigs, 57,016 (56.68%) were successfully annotated in seven public protein databases. From the differentially expressed gene (DEG) analysis, 926 DEGs were identified between the B group (low DHM: 210.31 mg/g) and D group (high DHM: 359.12 mg/g) libraries, including 446 up-regulated genes and 480 down-regulated genes (B vs. D). Flavonoids (DHQ, DHM)-related DEGs of ten structural enzyme genes, three myeloblastosis transcription factors (MYB TFs), one basic helix-loop-helix (bHLH) TF, and one WD40 domain-containing protein were obtained. The enzyme genes comprised three PALs, two CLs, two CHSs, one F3'H, one F3'5'H (directly converts DHQ to DHM), and one ANS. The expression profiles of randomly selected genes were consistent with the RNA-seq results. Our findings thus provide comprehensive gene expression resources for revealing the molecular mechanism from DHQ to DHM in A. grossedentata. Importantly, this work will spur further genetic studies about A. grossedentata and may eventually lead to genetic improvements of the DHQ content in this plant.

Evaluation of variability of silymarin complex in Silybi mariani fructus harvested during two production years

Milk thistle [Silybum marianum (L.) Gaertn.], a member of Asteraceae family, is one of the most cultivated medicinal plants widespread throughout the world. The pharmacological drug is a ripe fruit without pappus – Silybi mariani fructus – containing flavonolignans and generating silymarin complex. In folk medicine, it is used for the treatment of liver disorders, kidney problems, rheumatism as well as gastronomic disturbances, cardiac and neurotic disorders, and fever. The components of silymarin complex are useful in cancer prevention and treatment. The aim of the study was to determine the amount of silymarin complex contained in the fruit of the harvest of two consecutive years and how much they differ from one another. Representative samples of fruit were collected in 2015 and 2016 and distributed by a company Agrofos (Slovakia). Regarding the analytical method, we used a high-performance liquid chromatography (HPLC); the method was approved by the European Pharmacopoeia 10. The statistical significance was on the level P < 0.05. The total content of silymarin complex was 15.28 ± 0.06 g.kg−1 (in 2015) and 16.65 ± 0.09 g.kg−1 (in 2016). In both studied years, the highest representation of silybin B was observed (7.04 ± 0.07 g.kg−1 versus 5.92 ± 0.08 g.kg−1). The differences between the individual fractions of the silymarin complex were statistically significant. There was also a significant difference of 9% in the total silymarin content between 2015 and 2016. In conclusion, we can state that both samples of Silybi mariani fructus meet the requirements of the European Pharmacopoeia.

Evaluation of pro-apoptotic potential of taxifolin against liver cancer

Liver cancer is the second most common cause of cancer-induced deaths worldwide. Liver cirrhosis and cancer are a consequence of the abnormal angio-architecture formation of liver and formation of new blood vessels. This angiogenesis is driven by overexpression of hypoxia-inducible factor 1-alpha (Hif1-α) and vascular endothelial growth factor (VEGF). Apart from this, protein kinase B (Akt) is also impaired in liver cancer. Despite the advancement in conventional treatments, liver cancer remains largely incurable. Nowadays, the use of naturally occurring anticancer agents particularly flavonoids is subject to more attention due to their enhanced physicochemical properties. Therefore, this study underlines the use of a natural anticancer agent taxifolin in the treatment of liver cancer using hepatocellular carcinoma cell line HepG2 and Huh7. The aim of our study is to devise a natural and efficient solution for the disease prevalent in Pakistan. The study involved the assessment of binding of ligand taxifolin using molecular docking. The binding of taxifolin with the proteins (Hif1-α, VEGF and Akt) was calculated by docking using Vina and Chimera. Further evaluation was performed by cell viability assay (MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) Assay), colony formation assay, cell migration assay, DNA ladder assay and flow cytometry. To see whether taxifolin directly affected expression levels, analysis of gene expression of Hif1-α, VEGF and Akt was performed using real-time polymerase chain reaction (qPCR) and western blotting. In silico docking experiments revealed that these proteins showed favorable docking scores with taxifolin. Treatment with taxifolin resulted in the inhibition of the liver cancer growth and migration, and induced apoptosis in HepG2 and Huh7 cell lines at an inhibitory concentration (IC50) value of 0.15 µM and 0.22 µM, respectively. The expression of HIF1-α, VEGF and Akt was significantly reduced in a dose- dependent manner. The inhibitory effect of taxifolin on hepatic cells suggested its chemopreventive and therapeutic potential. The studied compound taxifolin exhibited pronounced pro-apoptotic and hepatoprotective potential. Our study has confirmed the pro-apoptotic potential of taxifolin in liver cancer cell lines and will pave a way to the use of taxifolin as a chemotherapeutic agent after its further validation on the animal models and humans based epidemiological studies.

Taxifolin ameliorate high-fat-diet feeding plus acute ethanol binge-induced steatohepatitis through inhibiting inflammatory caspase-1-dependent pyroptosis

Excessive alcohol drinking and a high-fat diet (HFD) promote steatohepatitis in the comorbidity of NAFLD and AFLD. Taxifolin (TAX) is a rich dihydroxyflavone compound found in onions, milk thistle and Douglas fir. We aimed to explore the intervention mechanism of TAX on chronic steatohepatitis induced by HFD feeding plus acute ethanol binge. We established an in vivo model by HFD feeding plus a single dose of ethanol binge, and established an in vitro model by oleic acid or palmitic acid on HepG2 cells to induce lipid accumulation. TAX regulated lipid synthesis by inhibiting the expression of SREBP1 and upregulating the PPARγ level. In addition, TAX inhibited the expression of P2X7R, IL-1β, and caspase-1. Moreover, TAX reduced the expression of caspase-1 activation; thereby inhibiting the recruitment of macrophages and neutrophils. TAX also improved the inflammatory response caused by caspase-1 activation in steatotic hepatocytes. TAX exhibited an inhibitory effect on lipid accumulation and caspase-1-related pyroptosis. Collectively, TAX has therapeutic potential as an intervention of steatohepatitis induced by alcohol combined with HFD and for preventing non-alcoholic fatty liver degeneration targeting caspase-1-dependent pyroptosis.

Acidic hydrolysis of astilbin and its application for the preparation of taxifolin from Rhizoma Smilacis Glabrae

The acidic hydrolysis of astilbin to produce its aglycone, taxifolin, was investigated in this study. The effects of aq. HCl concentration and temperature on the reaction were studied, and the kinetic parameters were calculated. The results showed that with higher aq. HCl concentration and temperature, the hydrolysis of astilbin became faster. The activation energy of the hydrolysis reaction under 1 mol L−1 aq. HCl was calculated with a value of 148.6 kJ mol−1. The reaction was successfully applied to produce taxifolin from a sample of Rhizoma Smilacis Glabrae. A simple method for the purification of taxifolin from Rhizoma Smilacis Glabrae was developed with purity of 97.5%.

Taxifolin attenuates the developmental testicular toxicity induced by di-n-butyl phthalate in fetal male rats

Di-n-butyl phthalate (DBP) is widely used in consumer products as a plasticizer. Here, we report a natural product taxifolin that can attenuate developmental and reproductive toxicity of DBP. Pregnant rats were daily gavaged with 500 mg/kg DBP alone or together with taxifolin (10 and 20 mg/kg) from gestational day (GD) 12-21. At GD21, sera and testes of male fetus were collected. DBP significantly lowered serum testosterone level at 500 mg/kg and taxifolin can completely reverse its action. DBP caused abnormal aggregation of fetal Leydig cells and taxifolin can reverse it. DBP down-regulated the expression of the genes of cholesterol side-chain cleavage enzyme (Cyp11a1), 17β-hydroxysteroid dehydrogenase 3 (Hsd17b3), and insulin-like 3 (Insl3) and taxifolin can reverse its action. DBP increased malondialdehyde levels and decreased superoxide dismutase and glutathione peroxidase expression and taxifolin can reverse it. DBP increased incidence of multinucleated gonocytes and taxifolin can prevent it. Moreover, DBP lowered sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) and phosphorylated AMP-activated protein kinase (pAMPK) signalling and taxifolin antagonized DBP. In conclusion, in utero exposure to DBP caused developmental/reproductive toxicity of male offspring via increasing reactive oxygen species and taxifolin is an effective food component that completely reverses DBP-mediated action.

An insight into the health-promoting effects of taxifolin (dihydroquercetin)

Taxifolin (3,5,7,3,4-pentahydroxy flavanone or dihydroquercetin) is a flavonoid commonly found in onion, milk thistle, French maritime pine bark and Douglas fir bark. It is also used in various commercial preparations like Legalon™, Pycnogenol^®, and Venoruton^®. This review focuses on taxifolin's biological activities and related molecular mechanisms. Published literatures were gathered from the scientific databases like PubMed, SciFinder, ScienceDirect, Wiley Online Library, Google Scholar, and Web of Science up to January 2019. Taxifolin showed promising pharmacological activities in the management of inflammation, tumors, microbial infections, oxidative stress, cardiovascular, and liver disorders. The anti-cancer activity was more prominent than other activities evaluated using different in vitro and in vivo models. Further research on the pharmacokinetics, in-depth molecular mechanisms, and safety profile using well-designed randomized clinical studies are suggested to develop a drug for human use.

The chemical composition of a cold-pressed milk thistle seed flour extract, and its potential health beneficial properties

Cold-pressed milk thistle seed flour was extracted with 50% acetone and evaluated for its phytochemical composition, and gut microbiota modulating, free radical scavenging, anti-inflammatory and anti-proliferative capacities. UHPLC-MS analysis detected fifteen compounds in the milk thistle seed flour extract with silychristin as the primary component followed by silybin B and isosilybins A & B. The milk thistle seed flour extract enhanced the total bacteria number and altered the abundance of a specific bacterial phylum or genus under the experimental conditions. The extract had RDSC, ORAC, HOSC, and ABTS˙+ scavenging capacities of 49, 634, 10 420 and 116 μmol Trolox equivalents (TE) per g flour, respectively. In addition, the milk thistle seed flour extract suppressed LPS induced IL-1β mRNA expression in the cultured J774A.1 mouse macrophages and the proliferation of LNCaP prostate cancer cells. The results suggest milk thistle seed flour's potential health benefits in functional foods.

The Synthesis Followed by Spectral and Calorimetric Evaluation of Stability of Human Milk Fat Substitutes Obtained from Thistle Milk and Lard

The central point of current investigations was the first time ever synthesis of modern substitutes of human milk fat followed by versatile evaluation of their oxidative properties. The enzymatic interesterification conducted at 70°C for 2, 4, and 6 hours, respectively, with milk thistle oil and lard blend as starting reactants was catalyzed by 1,3-specific lipase Lipozyme RM IM, obtained from Rhizomucor miehei. Pressure Differential Scanning Calorimetry (PDSC) and Fourier Transform Infrared Spectroscopy (FT-IR) were applied to evaluate quality of products formed. Although PDSC curves showed lower oxidative stability of newly synthesized fats as compared to both starting materials separately, they can be considered adequate substitutes of human fat milk fat, as distribution of fatty acids in triacylglycerol molecules of substitutes obtained is much alike human milk fat itself, as resulted from analysis of GC data collected. Obvious changes in chemical structure of fats occurring during interesterification resulted in specific alterations in IR spectra of processed materials. Spectral data accompanied by PLS technique were successfully used for accurate determination of oxidative stability of new fats through indirect procedure, i.e., IR-PDSC-reference analysis of induction time. Additionally IR data exclusively, i.e., without any reference data, occurred powerfully in discrimination of human fat milk substitutes obtained.

Amelioration of Alcoholic Liver Steatosis by Dihydroquercetin through the Modulation of AMPK-Dependent Lipogenesis Mediated by P2X7R-NLRP3-Inflammasome Activation

Dihydroquercetin (TAX) is the most abundant dihydroflavone found in onions, milk thistle, and Douglas fir bark. We investigated whether TAX could inhibit lipid accumulation in alcoholic liver steatosis in vivo and in vitro. An in vivo model was established by intragastrically treating mice with ethanol, and an in vitro model was created by treating HepG2 cells with ethanol. TAX regulated SREBP1 and ACC expression by elevating LKB1 and AMPK phosphorylation. Also, TAX upregulated SIRT1 expression, which was suppressed by ethanol intake. Decreased expression of P2X7R and NLRP3 and suppressed cleavage of caspase-1 by TAX resulted in the inhibition of IL-1β production and release. Additionally, TAX reduced lipogenesis and promoted lipid oxidation via the regulation of AMPK and ACC in ethanol-treated steatotic HepG2 cells. TAX downregulated IL-1β cleavage responses to LPS and ATP stimulation in HepG2 cells. P2X7R deficiency attenuated lipid accumulation, characterized by increased AMPK activity and decreased SREBP1 expression in ethanol-treated HepG2 cells. Our data showed that TAX exhibited the ability to inhibit lipogenesis and a hepatoprotective capacity, indicating that TAX has therapeutic potential for preventing alcoholic liver steatosis.

Taxifolin suppresses rat and human testicular androgen biosynthetic enzymes

Taxifolin is a flavonoid. It has been used as a chemopreventive agent and supplement. It may have some beneficial effects to treat prostate cancer by suppressing androgen production in Leydig cells. The objective of the present study was to study the effects of taxifolin on androgen production of rat Leydig cells isolated from immature testis and some rat and human testosterone biosynthetic enzyme activities. Rat Leydig cells were incubated with 100μM taxifolin without (basal) or with 10ng/ml luteinizing hormone (LH), 10mM 8-bromoadenosine 3',5'-cyclic monophosphate (8BR), and steroid enzyme substrates (20μM): 22R-hydroxychloesterol, pregnenolone, progesterone, and androstenedione. The medium concentrations of 5α-androstane-3α, 17β-diol (DIOL) and testosterone were measured. Taxifolin significantly suppressed basal, LH-stimulated, 8BR-stimulated, pregnenolone-mediated, and progesterone-mediated androgen production by Leydig cells. Further study demonstrated that taxifolin inhibited rat 3β-hydroxysteroid dehydrogenase and 17α-hydroxylase/17, 20-lyase with IC₅₀ values of 14.55±0.013 and 16.75±0.011μM, respectively. Taxifolin also inhibited these two enzyme activities in human testis with IC₅₀ value of about 100μM. Taxifolin was a competitive inhibitor for these two enzymes when steroid substrates were used. In conclusion, taxifolin may have benefits for the treatment of prostate cancer.

Pretreatment with dihydroquercetin, a dietary flavonoid, protected against concanavalin A-induced immunological hepatic injury in mice and TNF-α/ActD-induced apoptosis in HepG2 cells

We have previously demonstrated the hepatoprotective effect of dihydroquercetin (DHQ) against concanavalin A (Con A)-induced immunological hepatic injury in mice.

Recent advances in the analysis of flavonolignans of Silybum marianum

Extracts of milk thistle (Silybum marianum, Asteraceae) have been recognized for centuries as remedies for liver and gallbladder disorders. The active constituents of milk thistle fruits are flavonolignans, collectively known as silymarin. Flavonolignans in S. marianum are structurally diverse, 23 constituents have been isolated from purple- and white-flowering variants. Flavonolignans have a broad spectrum of bioactivities and silymarin has been the subject of intensive research for its profound pharmacological activities. Silymarin is extracted from the seeds, commercialized in standardized form, and widely used in drugs and dietary supplements. The thorough analysis of silymarin, its constituents and silymarin-containing products has a key role in the quality control of milk thistle-based products. Due to the low concentration of analytes, especially pharmacological and pharmacokinetic studies require more and more selective and sensitive, advanced techniques. The objective of the present review is to summarize the recent advances in the chemical analysis of S. marianum extracts, including the chemical composition, isolation and identification of flavonolignans, sample preparation, and methods used for qualitative and quantitative analysis. Various analytical approaches have been surveyed, and their respective advantages and limits are discussed.

Detection of 191 Taxifolin Metabolites and Their Distribution in Rats Using HPLC-ESI-IT-TOF-MS(n)

Taxifolin is a ubiquitous bioactive constituent of foods and herbs. To thoroughly explore its metabolism in vivo, an HPLC-ESI-IT-TOF-MSⁿ method combined with specific metabolite detection strategy was used to detect and identify the metabolites of taxifolin in rats. Of the 191 metabolites tentatively identified, 154 were new metabolites, 69 were new compounds and 32 were dimers. This is the first report of the in vivo biotransformation of a single compound into more than 100 metabolites. Furthermore, acetylamination and pyroglutamic acid conjugation were identified as new metabolic reactions. Seventeen metabolites were found to have various taxifolin-related bioactivities. The potential targets of taxifolin and 63 metabolites were predicted using PharmMapper, with results showing that more than 60 metabolites have the same five targets. Metabolites with the same fragment pattern may have the same pharmacophore. Thus these metabolites may exert the same pharmacological effects as taxifolin through an additive effect on the same drug targets. This observation indicates that taxifolin is bioactive not only in the parent form, but also through its metabolites. These findings enhance understanding of the metabolism and effective forms of taxifolin and may provide further insight of the beneficial effects of taxifolin and its derivatives.

Protective effect of polyphenols in an inflammatory process associated with experimental pulmonary fibrosis in mice

Polyphenols have been described to have a wide range of biological activities, and many reports, published during recent years, have highlighted the beneficial effects of phenolic compounds, illustrating their promising role as therapeutic tools in several acute and chronic disorders. The purpose of study was to evaluate, in an already-assessed model of lung injury caused by bleomycin (BLM) administration, the role of resveratrol and quercetin, as well as to explore the potential beneficial properties of a mango leaf extract, rich in mangiferin, and a grape leaf extract, rich in dihydroquercetin (DHQ), on the same model. Mice were subjected to intra-tracheal administration of BLM, and polyphenols were administered by oral route immediately after BLM instillation and daily for 7 d. Treatment with resveratrol, mangiferin, quercetin and DHQ inhibited oedema formation and body weight loss, as well as ameliorated polymorphonuclear infiltration into the lung tissue and reduced the number of inflammatory cells in bronchoalveolar lavage fluid. Moreover, polyphenols suppressed inducible nitric oxide synthase expression, and prevented oxidative and nitroxidative lung injury, as shown by the reduced nitrotyrosine and poly (ADP-ribose) polymerase levels. The degree of apoptosis, as evaluated by Bid and Bcl-2 balance, was also suppressed after polyphenol treatment. Finally, these natural products down-regulated cyclo-oxygenase-2, extracellular signal-regulated kinase phosphorylated expression and reduced NF-κBp65 translocation. Our findings confirmed the anti-inflammatory effects of resveratrol and quercetin in BLM-induced lung damage, and highlight, for the first time, the protective properties of exogenous administration of mangiferin and DHQ on experimental pulmonary fibrosis.

Taxifolin mitigates oxidative DNA damage in vitro and protects zebrafish (Danio rerio) embryos against cadmium toxicity

Taxifolin (TAX) is a natural source of bioflavonoid found in various conifers. In this study, initially we investigated the antioxidant potential of TAX under in vitro assays such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), ferric-ion reducing power (FRAP) and hydroxyl radical (OH). The activities of DPPH, ABTS, FRAP and OH radical levels were significantly inhibited by TAX with an IC50 values of 16.48, 66.34, 18.17 and 11.42μg/ml, respectively. Secondly, TAX exhibited a strong protection against OH mediated DNA damage on pUC19 plasmid DNA at 1.0μg/ml. Finally, we evaluated the protective mechanism of TAX against cadmium intoxicated zebrafish embryos (Danio rerio). We found that embryos exposed to 100μM Cd exhibited significantly reduced survival, delayed hatching and phenotypic abnormalities at 24, 48, 72 and 96hours post fertilization (hpf). Similarly, Cd intoxicated embryos showed significantly increased cardiac function (131beats/min) at 60hpf. Conversely, treatment with TAX (0.1, 1.0 and 10μM) significantly enhanced the antioxidant enzyme levels (SOD, CAT, GPx and GR) by reducing the lipid peroxidation (MDA) in zebrafish embryos. Collectively, our results concluded that TAX could act as a potent redox scavenger against oxidative DNA damage and also functions as a crucial suppressor of Cd toxicity in zebrafish embryos.

Development of an ionic liquid-based microwave-assisted method for the extraction and determination of taxifolin in different parts of Larix gmelinii

An ionic liquid-based microwave-assisted extraction method (ILMAE) was successfully applied for the extraction of taxifolin from Larix gmelinii. Different kinds of 1-alkyl-3-methylimidazolium ionic liquids with different kinds of cations and anions were studied and 1-butyl-3-methylimidazolium bromide was chosen as the optimal solvent for taxifolin extraction. The optimal conditions of ILMAE were determined by single factor experiments and Box-Behnken design as follows: [C₄mim]Br concentration of 1.00 M, soaking time of 2 h, liquid-solid ratio of 15:1 mL/g, microwave irradiation power of 406 W, microwave irradiation time of 14 min. No degradation of taxifolin had been observed under the optimum conditions as evidenced from the stability studies performed with standard taxifolin. Compared with traditional solvent and methods, ILMAE provided higher extraction yield, lower energy and time consumption. The distribution of taxifolin in different parts of larch and the influences of age, orientation, and season on the accumulation of taxifolin were analyzed for the sufficient utilization of L. gmelinii.

EWS Knockdown and Taxifolin Treatment Induced Differentiation and Removed DNA Methylation from p53 Promoter to Promote Expression of Puma and Noxa for Apoptosis in Ewing's Sarcoma

Ewing’s sarcoma is a pediatric tumor that mainly occurs in soft tissues and bones. Malignant characteristics of Ewing’s sarcoma are correlated with expression of EWS oncogene. We achieved knockdown of EWS expression using a plasmid vector encoding EWS short hairpin RNA (shRNA) to increase anti-tumor mechanisms of taxifolin (TFL), a new flavonoid, in human Ewing’s sarcoma cells in culture and animal models. Immunofluorescence microscopy and flow cytometric analysis showed high expression of EWS in human Ewing’s sarcoma SK-N-MC and RD-ES cell lines. EWS shRNA plus TFL inhibited 80% cell viability and caused the highest decreases in EWS expression at mRNA and protein levels in both cell lines. Knockdown of EWS expression induced morphological features of differentiation. EWS shRNA plus TFL caused more alterations in molecular markers of differentiation than either agent alone. EWS shRNA plus TFL caused the highest decreases in cell migration with inhibition of survival, angiogenic and invasive factors. Knockdown of EWS expression was associated with removal of DNA methylation from p53 promoter, promoting expression of p53, Puma, and Noxa. EWS shRNA plus TFL induced the highest amounts of apoptosis with activation of extrinsic and intrinsic pathways in both cell lines in culture. EWS shRNA plus TFL also inhibited growth of Ewing’s sarcoma tumors in animal models due to inhibition of differentiation inhibitors and angiogenic and invasive factors and also induction of activation of caspase-3 for apoptosis. Collectively, knockdown of EWS expression increased various anti-tumor mechanisms of TFL in human Ewing’s sarcoma in cell culture and animal models.

The Effect of Elephantopus scaber L. on Liver Regeneration after Partial Hepatectomy

Liver regeneration after partial hepatectomy (PHx) is a physiological response for maintaining homeostasis. The aim of this study is to investigate effects of Elephantopus scaber L.- (ESL-) induced liver regeneration on growth factors (HGF and IGF-1), cell cycle regulation, and apoptosis suppressed. In this study, we fed five Chinese medicinal herbs (1 g/kg/day), Codonopsis pilosula (CP, Dangshen), Salvia miltiorrhiza Bunge (SMB, Danshen,), Bupleurum kasi (BK, Chaihu), Elephantopus scaber L. (ESL, Teng-Khia-U), and Silymarin (Sm, 25 mg/kg) for 7 days to male Spraue-Dawley rats. Then surgical 2/3 PHx was conducted and liver regeneration mechanisms were estimated on the following 24 hrs and 72 hrs. The activities of growth factors (HGF and IGF-I) and cell cycle proteins were measured by Western blot and RT-PCR. Histological analysis and apoptosis were detected by H&E stain and TUNEL. The results showed that extraction of Elephantopus scaber L. (ESL) and Silymarin (Sm, positive control) were increased protein expression levels of HGF and IGF-1 which leads into cell cycle. These results suggest that the ESL plays a crucial role in cell cycle-induced liver regeneration and apoptosis. These results suggested that the ESL plays a crucial role in cell cycle-induced liver regeneration and suppressed hepatocytes apoptosis.

A sensitive LC-MS/MS assay for the simultaneous analysis of the major active components of silymarin in human plasma

Silymarin, an extract of crushed achenes of the milk thistle plant Silybum marianum is a multi-constituent mixture, 70-80% of which consists of a complex assortment containing the flavonolignans silybin A and B, isosilybin A and B, silydianin, and silychristin, and the flavonoid taxifolin. To date, numerous pharmacological actions of the silymarin extract have been documented in the biomedical literature, including hepatoprotective, anti-inflammatory, anti-tumor, and anti-fibrotic activities. The present study describes a novel liquid chromatographic-tandem mass spectrometric method for simultaneous analysis of silychristin, silydianin, silybin A and silybin B, isosilybin A and isosilybin B, and taxifolin in human plasma employing liquid-liquid extraction. This assay provides excellent resolution of the individual silymarin constituents via utilization of a 100 A 250 mm × 2 mm, 5 μm C(18) column with the mobile phase consisting of 51% methanol, 0.1% formic acid, and 10mM ammonium acetate. The lower limit of quantification was 2 ng/ml for each constituent. Calibration curves were linear over the range from 2 ng/ml to 100 ng/ml for all analytes (r(2)>0.99). The intra- and inter-day accuracies were 91-106.5% and 95.1-111.9%, respectively. The intra- and inter-day precision was within 10.5%. Additionally, recovery, stability, and matrix effects were fully validated as well. This method was successfully applied to human plasma samples from subjects treated with the milk thistle extract Legalon(®).

Taxifolin suppresses UV-induced skin carcinogenesis by targeting EGFR and PI3K

Skin cancer is one of the most commonly diagnosed cancers in the United States. Taxifolin reportedly exerts multiple biologic effects, but the molecular mechanisms and direct target(s) of taxifolin in skin cancer chemoprevention are still unknown. In silico computer screening and kinase profiling results suggest that the EGF receptor (EGFR), phosphoinositide 3-kinase (PI3K), and Src are potential targets for taxifolin. Pull-down assay results showed that EGFR, PI3K, and Src directly interacted with taxifolin in vitro, whereas taxifolin bound to EGFR and PI3K, but not to Src in cells. ATP competition and in vitro kinase assay data revealed that taxifolin interacted with EGFR and PI3K at the ATP-binding pocket and inhibited their kinase activities. Western blot analysis showed that taxifolin suppressed UVB-induced phosphorylation of EGFR and Akt, and subsequently suppressed their signaling pathways in JB6 P+ mouse skin epidermal cells. Expression levels and promoter activity of COX-2 and prostaglandin E(2) (PGE(2)) generation induced by UVB were also attenuated by taxifolin. The effect of taxifolin on UVB-induced signaling pathways and PGE(2) generation was reduced in EGFR knockout murine embryonic fibroblasts (MEF) compared with EGFR wild-type MEFs. Taxifolin also inhibited EGF-induced cell transformation. Importantly, topical treatment of taxifolin to the dorsal skin significantly suppressed tumor incidence, volume, and multiplicity in a solar UV (SUV)-induced skin carcinogenesis mouse model. Further analysis showed that the taxifolin-treated group had a substantial reduction in SUV-induced phosphorylation of EGFR and Akt in mouse skin. These results suggest that taxifolin exerts chemopreventive activity against UV-induced skin carcinogenesis by targeting EGFR and PI3K.

Dihydroquercetin: More than just an impurity?

Dihydroquercetin (taxifolin) is a potent flavonoid found in onions, French maritime bark, milk thistle, tamarind seeds and commercially available semi-synthetic monoHER marketed as Venoruton. This review focuses on the therapeutic promise of dihydroquercetin in major disease states such as cancer, cardiovascular disease and liver disease by reviewing the proposed mechanism(s) of action, including the activation of the antioxidant response element (ARE) and detoxifying phase II enzymes, inhibition of cytochrome P(450) and fatty acid synthase in carcinogenesis. TNF-alpha and NF-ĸB dependent transcription in hepatitis C infections, the scavenging effect of myeloperoxidase (MPO) derived reactive nitrogen species and subsequent effects on cholesterol biosynthesis as well as the effects on apob/apoA-I, HMG-CoA reductase and apoptosis are reviewed. The stereochemistry and pro-oxidant effect of dihydroquercetin are also considered. Although the majority of research on dihydroquercetin to date has focused on the identification of molecular targets in vitro, this review will bring together evidence of the potency and mode of action of dihydroquercetin and will propose a role for the therapeutic potential of flavonoid antioxidants.

Optimisation of enzyme assisted extraction of silybin from the seeds of Silybum marianum by Box-Behnken experimental design

INTRODUCTION

Silybin, a standardised extract of flavanolignans from the seeds of Silybum marianum, has been used for centuries as a natural remedy in the treatment of hepatitis and cirrhosis. The higher yield of silybin by using more efficient extraction technique is of particular interest in the herbal products manufacture.

OBJECTIVE

To systematically investigate the important factors of enzyme-assisted extraction of flavanolignans from the seeds of Silybum marianum to enhance the extraction yield of silybin.

METHODOLOGY

The important factors of enzyme-assisted extraction were optimised by employing Box-Behnken design with the aid of the orthogonal array design (OAD) OA(8) (2(7)). The effects of enzyme incubation temperature (EIT), the pH of enzyme solution (PES) and the size of seeds (SS) on the yield of silybin were visualised as three-dimensional response surface and contour plots.

RESULTS

The predictive yield was 24.6 mg/g defatted seeds under the optimum enzymolysis conditions (EIT 40 degrees C, PES 4.5 and SS 7003 microm). The coefficient of the model was r(2) > 0.97 (n = 15). The actual yield of silybin was 24.81 + or - 1.93 mg/g defatted seeds, higher by 138 and 123.6% than that from ethanol extraction in this study and in the previous literature, respectively. IR spectra and HPLC of the extracts by EAE were in agreement with those from ethanol extraction. SEM and TEM pictures of defatted seeds by variant extractions demonstrate that the extraction of silybin depends on the destruction of cell walls.

CONCLUSION

The results suggest that EAE is a promising alternative for the extraction of silybin by the use of traditional ethanol extraction.

Pretreatment of milk thistle seed to increase the silymarin yield: an alternative to petroleum ether defatting

Milk thistle (Silybum marianum L.) seed meal is extracted for the flavonolignans, silychristin, silydianin, silybinin A, silybinin B, isosilybinin A and isosilybinin B, which are collectively known as the silymarin complex. To obtain the flavonolignans, the meal is usually treated with successive washes of petroleum ether to remove the lipids, followed by extraction of the flavonolignans with ethanol. This work examines the possible replacement of petroleum ether and ethanol by water or other aqueous solutions in these processes. To replace petroleum ether, pretreatments with 1.2% NaOH (w/w), 1.5% H2SO4 (w/w), 2% NaHCO3 (w/w), 0.14% cellulase and water were investigated. Of these pretreatments, 1.5% H2SO4 and water produced similar flavonolignan yields as petroleum ether. Results established that pretreating the milk thistle seed meal with 1.5% H2SO4 (w/w) at 50 degrees C for 18 h could replace the petroleum ether pretreatment. In addition, it was shown that similar amounts of flavonolignan could be recovered with a 1.5% H2SO4/water (100 degrees C) extraction as with a petroleum ether/ethanol extraction. Although cellulase pretreatment was not examined extensively, significant advances in cellulase effectiveness and cost have occurred in the past few years by companies such as Genencor International and Novozymes. These advances should help to make enzyme use for cellulose conversion, as well as extraction pretreatment, technically and economically feasible.

Analysis of silibinin in rat plasma and bile for hepatobiliary excretion and oral bioavailability application

Silibinin is an herbal ingredient isolated from milk thistle. The aim of this study was to develop a simple liquid chromatographic system to assay silibinin in plasma and bile for pharmacokinetic study. Silibinin was given oral and intravenously. The plasma sample (25 microL) was vortex-mixed with 50 microL of internal standard solution (naringenin 10 microg/mL in acetonitrile) to achieve protein precipitation. Silibinin in the rat plasma and bile was separated using a reversed-phase C18 column (250 mm x 4.6 mm, 5 microm) with a mobile phase of acetonitrile -10 mM monosodium phosphate (pH 5.45 adjusted with orthophosphoric acid) (50:50, v/v) and the flow-rate of 1 mL/min. The UV detection wavelength was 288 nm. The concentration-response relationship from the present method indicated linearity over a concentration range of 0.5-100 microg/mL. Intra- and inter-assay precision and accuracy of silibinin fell well within the predefined limits of acceptability (<15%). An ultrafiltration method was used in this experiment and the protein binding of silibinin was 70.3+/-4.6%. After silibinin administration in rats, the disposition of silibinin in the plasma and bile fluid was due to rapid distribution and equilibration between the blood and hepatobiliary system, and the bile levels of unconjugated silibinin and total silibinin were greater than those in the plasma. The oral bioavailability of silibinin in rats was estimated to be 0.73%.

Milk thistle nomenclature: why it matters in cancer research and pharmacokinetic studies

Extracts of milk thistle have been recognized for centuries as "liver tonics" and are well-known to prevent or reverse hepatotoxicity of reactive drug metabolites or naturally occurring toxins. Milk thistle extracts are now under intense study in the experimental therapeutics of cancer for chemoprevention, treatment, and amelioration of chemotherapy side effects. Precision in nomenclature, however, has lagged behind this progress. The crude commercial product of milk thistle is termed silymarin, a complex of at least 7 flavonolignans and 1 flavonoid that comprises 65% to 80% of milk thistle extract. From silymarin is derived silibinin, a semipurified fraction once thought to be a single compound but now recognized as a 1:1 mixture of 2 diastereoisomers, silybin A and silybin B. The distinction between silymarin and silibinin is not only important to understanding the historical literature, but thorough characterization and use of chemically defined mixtures in preclinical and clinical studies are essential to the progress of these botanical compounds as human therapeutics. As a result, we urge clinicians and preclinical investigators alike to exercise rigor in nomenclature and use pure compounds or precisely defined chemical mixtures in subsequent studies. Herein, we provide a guide to the proper nomenclature and composition of milk thistle extracts and discuss the known pharmacokinetic studies of these botanical medicines. The drug-interaction potential of these extracts appears to be quite low, and in fact, silibinin appears to synergize with the antitumor effects of some commonly used chemotherapeutics. However, some precautions are advised as high-dose, phase II studies are conducted.

Inhibition of T-cell inflammatory cytokines, hepatocyte NF-kappaB signaling, and HCV infection by standardized Silymarin

BACKGROUND & AIMS

Chronic hepatitis C is a serious global medical problem necessitating effective treatment. Because standard of care with pegylated interferon plus ribavirin therapy is costly, has significant side effects, and fails to cure about half of all infections, many patients seek complementary and alternative medicine to improve their health, such as Silymarin, derived from milk thistle (Silybum marianum). Milk thistle's clinical benefits for chronic hepatitis C are unsettled due to variability in standardization of the herbal product.

METHODS

In the current study, we focused on the anti-inflammatory and antiviral properties of a standardized Silymarin extract (MK-001).

RESULTS

MK-001 inhibited expression of tumor necrosis factor-alpha in anti-CD3 stimulated human peripheral blood mononuclear cells and nuclear factor kappa B-dependent transcription in human hepatoma Huh7 cells. Moreover, MK-001 dose dependently inhibited infection of Huh7 and Huh7.5.1 cells by JFH-1 virus. MK-001 displayed both prophylactic and therapeutic effects against HCV infection, and when combined with interferon-alpha, inhibited HCV replication more than interferon-alpha alone. Commercial preparations of Silymarin also displayed antiviral activity, although the effects were not as potent as MK-001. Antiviral effects of the extract were attributable in part to induction of Stat1 phosphorylation, while interferon-independent mechanisms were suggested when the extract was biochemically fractionated by high-performance liquid chromatography. Silybin A, silybin B, and isosilybin A, isosilybin B elicited the strongest anti-NF-kappaB and anti-HCV actions. These effects were independent of MK-001-induced cytotoxicity.

CONCLUSIONS

The data indicate that Silymarin exerts anti-inflammatory and antiviral effects, and suggest that complementary and alternative medicine-based approaches may assist in the management of patients with chronic hepatitis C.

Analysis and comparison of active constituents in commercial standardized silymarin extracts by liquid chromatography-electrospray ionization mass spectrometry

A sensitive method for the simultaneous quantitation of six active constituents in commercial silymarin standardized extracts was developed based on liquid chromatography (LC) in combination with mass spectrometry (MS). The six main active constituents, namely, silydianin, silychristin, diastereoisomers of silybin (silybin A and B), and diastereoisomers of isosilybin (isosilybin A and B) were completely separated and quantified by LC/MS. Silymarin obtained from Sigma-Aldrich Co. was evaluated and used as standard reference material for the six individual constituents in comparing the relative content of silymarin and the relative ratio of each constituent in commercial standardized silymarin extracts, respectively. Significant variation was found between different commercial silymarin sources. As a result, this method has proven useful in evaluating and quantifying the six active constituents in commercial milk thistle extracts. The calibration curves were over the range from 0.25 to 100 microg/mL for silychristin and silydianin, and from 0.10 to 100 microg/mL for silybin A, silybin B, isosilybin A and isosilybin B, respectively (r(2)> or =0.9958). For all six active constituents, the overall intra-day precision values, based on the relative standard deviation replicate for four QC levels, ranged from 1.18% to 12.4% and accuracy ranged from 89.4% to 112%. This methodology could easily be incorporated into standardized testing to assess content uniformity including lot-to-lot variation as part of routine process controls as well as a means to describe cross-product variation among the exiting marketed formulations.

Separation and characterization of silybin, isosilybin, silydianin and silychristin in milk thistle extract by liquid chromatography-electrospray tandem mass spectrometry

A selective and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed for the characterization of silymarin in commercially available milk thistle extract. In this study, six main active constituents, including silydianin, silychristin, diastereomers of silybin (silybin A and B) and diastereomers of isosilybin (isosilybin A and B) in silymarin, were completely separated on a YMC ODS-AQ HPLC column using a gradient mobile phase system comprised of ammonium acetate and methanol/water/formic acid. Identification and characterization of the major constituents were based not only on the product ion scan, which provided unique fragmentation information of a selected molecular ion, but also on the specific fragmentation of multiple reaction monitoring (MRM) data, which confirmed the retention times of LC chromatographic peaks. The method was applied in the analysis of human plasma samples in the presence of silymarin and appeared to be suitable for the pharmacokinetic studies in which the discrimination of silymarin constituents is essential.