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Silybum marianum, commonly known as milk thistle, is renowned for its potent antioxidant and hepatoprotective properties, primarily attributed to its active compound, silymarin. This study investigates the antioxidant and hepatoprotective effects of Silybum marianum extract against carbon tetrachloride (CCl4)-induced hepatotoxicity in Wistar rats. The extract was prepared through ethanol-based solvent extraction and subjected to preliminary phytochemical screening, revealing the presence of tannins, alkaloids, saponins, flavonoids, glycosides, steroids and terpenoids. Hepatoprotective efficacy was assessed by measuring serum biochemical markers such as AST, ALT, ALP, total bilirubin and MDA levels, alongside histopathological analysis of liver tissues. Rats treated with Silybum marianum extract showed significant improvements in liver function and oxidative stress markers compared to the CCl4 control group. The extract also enhanced antioxidant enzyme activities such as superoxide dismutase (SOD) and glutathione peroxidase (GPx). These findings suggest that Silybum marianum holds therapeutic potential for protecting the liver against oxidative damage and inflammation. Further clinical studies are warranted to validate its efficacy and optimize therapeutic applications. [ABSTRACT FROM AUTHOR]

Supercritical fluid extraction with carbon dioxide is nowadays one of the best approaches on an economic and ecological point of view for the extraction of natural compounds from plants. Besides, many seeds or fruits contain both lipids, as triglycerides, which can be used for food or cosmetic industries, and polyphenols which do have many bioprotective effects for the human health. By using successively pure carbon dioxide and carbon dioxide added with a polar modifier, either pure ethanol or a ethanol/water mixture, we achieved first the extraction of triglycerides of the milk thistle seeds, followed by the extraction of the flavonolignans, which are bioactive compounds. Effects of pressure (15 and 25 MPa) and temperature (40 and 60 °C) were studied on the lipids extraction efficiency. For flavonolignans, the polar compounds, the impact of modifier amount (pure ethanol from 10% to 40%) and water percentage in ethanol (5–15%) were compared. The duration of the two sequential steps to achieve the complete seed defatting and to increase the flavonolignan recovery were also studied. The complete lipids extraction was achieved with pure CO2 at 40 °C, 25 MPa for 30 min whereas the extraction of flavonolignans was achieved with 20% of modifier (wate/ethanol 15/85) during 90 min. The analysis of the triglyceride composition of milk thistle seed were studied by using supercritical fluid chromatography (SFC), whereas the analysis of flavonolignans was carried out by an improved Ultra-high-pressure liquid chromatography (UHPLC) method.

Herbal chemicals with a long history in medicine have attracted a lot of attention. Flavonolignans and flavonoids are considered as two classes of the above-mentioned compounds with different functional groups which exhibit several therapeutic capabilities such as antimicrobial, anti-inflammatory, antioxidant, antidiabetic, and anticancer activities. Based on the studies, high hydrophobic properties of the aforementioned compounds limit their bioavailability inside the human body and restrict their wide application. Nanoscale formulations such as solid lipid nanoparticles, liposomes, and other types of lipid-based delivery systems have been introduced to overcome the above-mentioned challenges. This approach allows the aforementioned hydrophobic therapeutic compounds to be encapsulated between hydrophobic structures, resulting in improving their bioavailability. The above-mentioned enhanced delivery system improves delivery to the targeted sites and reduces the daily required dosage. Lowering the required daily dose improves the performance of the drug by diminishing its side effects on non-targeted tissues. The present study aims to highlight the recent improvements in implementing lipid-based nanocarriers to deliver flavonolignans and flavonoids. [ABSTRACT FROM AUTHOR]

Advancements in the field of research and development have paved toward the use of herbal agents to cure and control health maladies. Milk thistle (Silybum marianum L.) is one of the herbs that possess pharmacological and therapeutic attributes. Various bioactive components in milk thistle have a key role in pathological conditions like blood-related disorders, hepatic ailments, arthritis, ulcerative colitis, and carcinomas. Among various bioactive components, silymarin is an active agent which isa standardized mixture of flavonolignans (70%–80%) along with silybin, silydianin, and silychristin, with silybin being the main active chemical component. Silymarin has been used medicinally to treat liver disorders, including acute and chronic viral hepatitis, toxin/drug-induced hepatitis, cirrhosis, and alcoholic liver diseases. Traditionally, the plant was employed to increase human reproduction ability, possess reactive oxygen species (ROS) scavenging, antioxidant, anti-inflammatory and immunomodulatory properties, has UV-induced skin damage protection, maintains the menstrual cycle, lessen viral infection, decrease fibrosis, and blood glucose as well as improve functions of the liver, pancreas, and reproductive cells. This review summarizes the basic as well as advanced therapeutic effects of silymarin which will ultimately lead researchers in developinphytopharmaceutical-based complementary medicine. [ABSTRACT FROM AUTHOR]

This study examined the metabolism of flavonolignans and taxifolin in 33 healthy adult male volunteers, who received 200 mg of silymarin orally twice daily for three months. First-morning urine and feces collected on days 10 and 90 were analyzed by UHPLC-MS and bacterial composition of feces was investigated by Next Generation Sequencing. The analyses revealed 5/4 types of flavonolignan/taxifolin metabolites in urine and 13/10 types of metabolites in feces, with large differences in total metabolite levels in both urine and feces observed among individual participants. In urine, 21 and 23 participants showed some increase in the total amount of flavonolignan and taxifolin metabolites, respectively, on day 90 compared with day 10. In feces, some correlation was found between the amount of metabolites and the composition of the intestinal microbiota. In conclusion, silymarin flavonolignans and taxifolin undergo multiple biotransformation reactions, and the metabolic profiles of the constituents considerably vary among individuals.

A library of previously unknown halogenated derivatives of flavonolignans (silybins A and B, 2,3-dehydrosilybin, silychristin A, and 2,3-dehydrosilychristin A) was prepared. The effect of halogenation on the biological activity of flavonolignans was investigated. Halogenated derivatives had a significant effect on bacteria. All prepared derivatives inhibited the AI-2 type of bacterial communication (quorum sensing) at concentrations below 10 µM. All prepared compounds also inhibited the adhesion of bacteria (Staphyloccocus aureus and Pseudomonas aeruginosa) to the surface, preventing biofilm formation. These two effects indicate that the halogenated derivatives are promising antibacterial agents. Moreover, these derivatives acted synergistically with antibiotics and reduced the viability of antibiotic-resistant S. aureus. Some flavonolignans were able to reverse the resistant phenotype to a sensitive one, implying that they modulate antibiotic resistance. [ABSTRACT FROM AUTHOR]

Herbal chemicals with a long history in medicine have attracted a lot of attention. Flavonolignans and flavonoids are considered as two classes of the above-mentioned compounds with different functional groups which exhibit several therapeutic capabilities such as antimicrobial, anti-inflammatory, antioxidant, antidiabetic, and anticancer activities. Based on the studies, high hydrophobic properties of the aforementioned compounds limit their bioavailability inside the human body and restrict their wide application. Nanoscale formulations such as solid lipid nanoparticles, liposomes, and other types of lipid-based delivery systems have been introduced to overcome the above-mentioned challenges. This approach allows the aforementioned hydrophobic therapeutic compounds to be encapsulated between hydrophobic structures, resulting in improving their bioavailability. The above-mentioned enhanced delivery system improves delivery to the targeted sites and reduces the daily required dosage. Lowering the required daily dose improves the performance of the drug by diminishing its side effects on non-targeted tissues. The present study aims to highlight the recent improvements in implementing lipid-based nanocarriers to deliver flavonolignans and flavonoids.

• The anti-diabetic effects of Chamaerops humilis methanol extract (CHME) and five identified compounds named: tricin-7-rutinoside (1), tricin (2), dihydrotricin (3), (salcolin A) (4a), (salcolin B) (4b), and (-)-(5s, 6s)-5,6-dihydro-3,8,10-trihydroxy-5-(4-hydroxy-3-methoxyphenyl)-6-hydroxymethyl-2,4-dimethoxy 7H benzo [e] xanthen-7-one (5) were evaluated in-vivo and in-vitro. • The beneficial activities of CHME were attributed to its phenolic content. • CHME extract exhibited an antidiabetic effect by controlling hyperglycaemia and reducing the inflammatory response including TNF-α, IL6, and MMP-1, were downregulated by CHME treatment. • Molecular docking simulations indicated that compounds 1, 2, and 3 had higher binding energies compared to the reference drug acarbose when tested against α-glucosidase and α-amylase. Five compounds were isolated from the aerial parts of Chamaerops humilis L. and characterized as tricin-7-rutinoside (1), tricin (2), dihydrotricin (3) diasteroisomer of tricin 4′-O(erythro-β-guaiacyl glyceryl) ether (salcolin A)(4a), tricin-4′-O-(threo-β-guaiacyl glyceryl) ether (salcolin B) (4b) and (-)-(5s, 6s)-5,6-dihydro-3,8,10-trihydroxy-5-(4-hydroxy-3-methoxyphenyl)-6-hydroxymethyl-2,4-dimethoxy 7H benzo [e] xanthen-7-one (5). Their structures were elucidated by comparing their spectral data with those reported in the literature. To the best of our knowledge, compounds (3-5) were reported here for the first time from Chamaerops humilis. The methanolic extract of Chamaerops humilis (CHME) and the five isolated compounds were studied for its anti-diabetic effect using in vitro α-glucosidase and α-amylase inhibitory assay that showed a significant activity. The toxicological study indicated that CHME was safe up to 5000 mg/kg bw. Two doses were selected for the in vivo study (800 and 1600 mg/kg bw) and orally administered to high fat diet/streptozotocin-induced diabetic rats for 10 consecutive days. The results revealed that the CHME improved the blood glucose levels in a dose dependent manner, the dose 1600 mg/kg showed the best results dependently along the period of the experiment. CHME and the five isolated compounds were evaluated in silico for their anti-diabetic effect. The anti-inflammatory effect of CHME (1600 mg/kg bw) was proved by significant downregulation of expression for interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and matrix metalloproteinase-1 (MMP-1) genes. In conclusion, CHME and its constituents may be a potential hypoglycemic agent working through the anti-inflammatory and enzyme inhibitory pathways. The docking studies demonstrated that compounds Tricin7-rutinoside and Salcolin isomers had promising binding energies of -9.10 kcal/mol and -8.70 kcal/mol, respectively, against α-amylase. These binding energies were superior to that of acarbose, which had a binding energy of -7.60 kcal/mol. In addition, docking analysis provided promising results for the inhibition of α-glucosidase by Tricin7-rutinoside and Dihydrotricin with binding affinity -7.9 kcal/mol and -7.9 kcal/mol, respectively while the binding affinity of acarbose is -6.40 kcal/mol. Overall, the methanolic extract from Chamaerops humilis exhibited good in silico of α-amylase and α-glucosidase enzyme inhibition potential. These findings suggest that these compounds may have potential as anti-diabetic agents, with further research needed to verify their efficacy and safety. [ABSTRACT FROM AUTHOR]

Salinity is an important challenge around the world, effecting all physiological and biochemical processes of plants. It seems that seed priming can diminish the negative impacts of salinity. To study the effects of hydro-priming and inoculation with Piriformospora indica (Pi) and Azotobacter chroococcum (Az) on physio-biochemical traits, flavonolignans and fatty acids composition of milk thistle under saline conditions, a greenhouse experiment was carried out. Our results indicated that under salinity, seed priming, especially Pi, improved physio-biochemical properties in milk thistle. Under 120 mM NaCl, inoculation with Pi increased membrane stability index (MSI) and relative water content (RWC) (by 21.86 and 33.43%, respectively). However, peroxidase (POX) (5.57- and 5.68-fold in roots and leaves, respectively), superoxide dismutase (SOD) (4.74- and 4.44-fold in roots and leaves, respectively), catalase (CAT) (6.90- and 8.50-fold in roots and leaves, respectively) and ascorbate peroxidase (APX) (5.61- and 5.68-fold in roots and leaves, respectively) activities increased with increasing salinity. Contrary to salinity, hydro-priming with Az and Pi positively altered all these traits. The highest content of the osmolytes, adenosine triphosphate (ATP) content and rubisco activity were recorded in Pi treatments under 120 mM NaCl. Stearic acid (20.24%), oleic acid (21.06%) and palmitic acid (10.48%) increased, but oil content (3.81%), linolenic and linoleic acid content (22.21 and 15.07%, respectively) decreased under saline conditions. Inoculations of Pi positively altered all these traits. The present study indicated that seed priming with Pi under 120 mM NaCl resulted in maximum silychristin, taxidolin, silydianin, isosilybin, silybin and silymarin of milk thistle seeds. [ABSTRACT FROM AUTHOR]

Objectives: Plant-derived flavonolignans had been demonstrated to have various biological functions. They are an important class of natural products combined by a flavonoid unit and a phenylpropanoid unit. Key findings: From the literature survey, 88 constituents from natural resources were identified. Different derivatives of flavonolignans were listed, fused phenylpropanoid unit with dioxane ring, or cyclic ether, or simple ether side chain, or lactone, and so on. Besides, the pharmacological effects of flavonolignans were summarized as well. It has a wide range of anti-tumour, antioxidant, anti-microorganic and anti-inflammatory effects. Summary: This review had provided a full-scale profile of flavonolignans on its plant sources, phytochemistry and pharmacology, and also proposed some issues and perspectives which may be of concern in the future. It was greatly anticipated that the commercialization of the flavonolignans would lead to uplift the financial abilities of communities attending the growing of the flavonolignans and the relevant and potential production becoming an international herbal and pharmaceutical commodity. [ABSTRACT FROM AUTHOR]

Silybum marianum (L.) Gaertn. (Asteraceae) was hydroponically cultured using a nutrient film technique system. Silibinin, isosilibinin and silychristin were detected in the fruits of the cultured plants. The effect of salicylic acid on the improvement of flavonolignans production by the fruits of the hydroponically cultured S. marianum was investigated. Salicylic acid was added to the nutrient solution at different concentrations (100, 200 and 400 µM) and the mature fruits of the plant were collected five days after elicitor addition. The fruits were then analyzed for their total flavonolignans contents and individual components using quantitative proton nuclear magnetic resonance spectroscopy (qHNMR) and high-performance liquid chromatography (HPLC). The results showed that elicitation with salicylic acid at 200 µM for five days increased production of total flavonolignans (1.7-fold by qHNMR and 1.6-fold by HPLC) higher than the control cultures and (1.4-fold by qHNMR and 1.1-fold by HPLC) higher than the cultivated plants. Silychristin was the major flavonolignan produced by the cultured plant. Elicitation by 200 µM salicylic acid increased silychristin production (1.6-fold by qHNMR and HPLC) higher than the control cultures and (1.3-fold by qHNMR and 1.0-fold by HPLC) higher than the cultivated plants. The present study provides a chance to improve secondary metabolite yield, serves as a useful tool for studying the biosynthesis of these medicinally valuable compounds and its regulation in plant and spots more light on hydroponic system as an important agricultural technique.

Taraxacum officinale , a cosmopolitan perennial, is widely used as an edible, fodder, honey, and medicinal plant. Interestingly, detailed LC-QTOF-MS profiling of the flower extract revealed the presence of several flavonoid signals, most likely lacking literature confirmation. Targeted isolation, including extraction based on DoE planning, led to the isolation of 11 flavonoids, three of which were new ( 16 , 18 , and 33 ). Their structures were determined by the NMR technique. Both biflavones ( 16 and 18 ) were structured by two luteolin molecules, linked by a C-C bond through IB (C-6') and IIA (C-6″ or C-8″) rings. Novel flavonolignan ( 33 ) was composed of tricin and an unusual carboxyl function containing a lignan moiety. The content of 28 flavonoids (glycosides, aglycones, biflavones, and flavonolignans) was determined by the LC-MS/MS method in raw flowers and dandelion syrups and tincture. Multivariate analyses showed the separation of spring and autumn flowers and a high diversity of food products and helped to identify metabolites correlated with the samples.

In the last few decades, targeting cancer by the use of dietary phytochemicals has gained enormous attention. The plausible reason and believe or mind set behind this fact is attributed to either lesser or no side effects of natural compounds as compared to the modern chemotherapeutics, or due to their conventional use as dietary components by mankind for thousands of years. Silibinin is a naturally derived polyphenol (a flavonolignans), possess following biochemical features; molecular formula C 25 H 22 O 10 , Molar mass: 482.44 g/mol, Boiling point 793 °C, with strikingly high antioxidant and anti-tumorigenic properties. The anti-cancer properties of Silibinin are determined by a variety of cellular pathways which include induction of apoptosis, cell cycle arrest, inhibition of angiogenesis and metastasis. In addition, Silibinin controls modulation of the expression of aberrant miRNAs, inflammatory response, and synergism with existing anti-cancer drugs. Therefore, modulation of a vast array of cellular responses and homeostatic aspects makes Silibinin an attractive chemotherapeutic agent. However, like other polyphenols, the major hurdle to declare Silibinin a translational chemotherapeutic agent, is its lesser bioavailability. After summarizing the chemistry and metabolic aspects of Silibinin, this extensive review focuses on functional aspects governed by Silibinin in chemoprevention with an ultimate goal of summarizing the evidence supporting the chemopreventive potential of Silibinin and clinical trials that are currently ongoing, at a single platform. [ABSTRACT FROM AUTHOR]

Silybum marianum (L.) Gaertn. (Asteraceae), commonly known as milk thistle, is a botanical natural product used to self‐treat multiple diseases such as Type 2 diabetes mellitus and nonalcoholic steatohepatitis (NASH). An extract from milk thistle seeds (achenes), termed silymarin, is comprised primarily of several flavonolignans. Systemic concentrations of these flavonolignans can influence the potential biologic effects of silymarin and the risk for pharmacokinetic silymarin‐drug interactions. The aims of this research were to determine the roles of organic anion transporting polypeptides (OATPs/Oatps) in silymarin flavonolignan disposition and in pharmacokinetic silymarin‐drug interactions. The seven major flavonolignans from silymarin were determined to be substrates for OATP1B1, OATP1B3, and OATP2B1. Sprague Dawley rats were fed either a control diet or a NASH‐inducing diet and administered pitavastatin (OATP/Oatp probe substrate), followed by silymarin via oral gavage. Decreased protein expression of Oatp1b2 and Oatp1a4 in NASH animals increased flavonolignan area under the plasma concentration‐time curve (AUC) and maximum plasma concentration. The combination of silymarin inhibition of Oatps and NASH‐associated decrease in Oatp expression caused an additive increase in plasma pitavastatin AUC in the animals. These data indicate that OATPs/Oatps contribute to flavonolignan cellular uptake and mediate the interaction between silymarin and NASH on pitavastatin systemic exposure. [ABSTRACT FROM AUTHOR]

Salinity is an important challenge around the world, effecting all physiological and biochemical processes of plants. It seems that seed priming can diminish the negative impacts of salinity. To study the effects of hydro-priming and inoculation with Piriformospora indica (Pi) and Azotobacter chroococcum (Az) on physio-biochemical traits, flavonolignans and fatty acids composition of milk thistle under saline conditions, a greenhouse experiment was carried out. Our results indicated that under salinity, seed priming, especially Pi, improved physio-biochemical properties in milk thistle. Under 120 mM NaCl, inoculation with Pi increased membrane stability index (MSI) and relative water content (RWC) (by 21.86 and 33.43%, respectively). However, peroxidase (POX) (5.57- and 5.68-fold in roots and leaves, respectively), superoxide dismutase (SOD) (4.74- and 4.44-fold in roots and leaves, respectively), catalase (CAT) (6.90- and 8.50-fold in roots and leaves, respectively) and ascorbate peroxidase (APX) (5.61- and 5.68-fold in roots and leaves, respectively) activities increased with increasing salinity. Contrary to salinity, hydro-priming with Az and Pi positively altered all these traits. The highest content of the osmolytes, adenosine triphosphate (ATP) content and rubisco activity were recorded in Pi treatments under 120 mM NaCl. Stearic acid (20.24%), oleic acid (21.06%) and palmitic acid (10.48%) increased, but oil content (3.81%), linolenic and linoleic acid content (22.21 and 15.07%, respectively) decreased under saline conditions. Inoculations of Pi positively altered all these traits. The present study indicated that seed priming with Pi under 120 mM NaCl resulted in maximum silychristin, taxidolin, silydianin, isosilybin, silybin and silymarin of milk thistle seeds.

Silybum marianum (L.) Gaertn. (Asteraceae) was hydroponically cultured using a nutrient film technique system. Silibinin, isosilibinin and silychristin were detected in the fruits of the cultured plants. The effect of salicylic acid on the improvement of flavonolignans production by the fruits of the hydroponically cultured S. marianum was investigated. Salicylic acid was added to the nutrient solution at different concentrations (100, 200 and 400 µM) and the mature fruits of the plant were collected five days after elicitor addition. The fruits were then analyzed for their total flavonolignans contents and individual components using quantitative proton nuclear magnetic resonance spectroscopy (qHNMR) and high-performance liquid chromatography (HPLC). The results showed that elicitation with salicylic acid at 200 µM for five days increased production of total flavonolignans (1.7-fold by qHNMR and 1.6-fold by HPLC) higher than the control cultures and (1.4-fold by qHNMR and 1.1-fold by HPLC) higher than the cultivated plants. Silychristin was the major flavonolignan produced by the cultured plant. Elicitation by 200 µM salicylic acid increased silychristin production (1.6-fold by qHNMR and HPLC) higher than the control cultures and (1.3-fold by qHNMR and 1.0-fold by HPLC) higher than the cultivated plants. The present study provides a chance to improve secondary metabolite yield, serves as a useful tool for studying the biosynthesis of these medicinally valuable compounds and its regulation in plant and spots more light on hydroponic system as an important agricultural technique. [ABSTRACT FROM AUTHOR]

This review provides a systematic and in-depth overview of the promise and potential of milk thistle (Silybum marianum) as an interesting alternative nutraceutical preparation for pharmaceutical and medicinal applications. Moreover, it aims to summarize and update the existing evidence of extract of milk thistle in the treatment of various diseases by in vitro, in vivo, and clinical studies, and special care is paid to the action mechanisms. The main active component of milk thistle, collectively known as silymarin, consists of a mixture of flavonolignans and flavonoid taxifolin. Silymarin acts as a hepatoprotective, anticancer, anti-inflammatory, immunomodulatory, neuroprotective and lactogenic agent. Precise mechanisms of silymarin action still needs investigations and molecular/genetic background of silymarin synthesis is crucial to be elucidated for reinforcement of the therapeutical potential of the plant by breeding. [ABSTRACT FROM AUTHOR]

Abstract Background Arachidonic acid metabolism by cyclooxygenase (COX) is a major pathway for blood platelets’ activation, which is associated with pro-thrombotic platelet activity and the production of pro-inflammatory mediators. Inhibition of COX activity is one of the major means of anti-platelet pharmacotherapy preventing arterial thrombosis and reducing the incidence of cardiovascular events. Recent studies have presented that a silymarin (standardized extract of Milk thistle (Silybum marianum)) can inhibit the COX pathway. Accordingly, the aim of our study was to determine the effects of three major flavonolignans (silybin, silychristin and silydianin) on COX pathway activity in blood platelets. Methods We determined the effect of flavonolignans on arachidonic acid induced blood platelet aggregation, COX pathway metabolites formation, as well as COX activity in platelets. Additionally, we analysed the potential mechanism of this interaction using the bioinformatic ligand docking method. Results We observed that tested compounds decrease the platelet aggregation level, both thromboxane A2 and malondialdehyde formation, as well as inhibit the COX activity. The strongest effect was observed for silychristin and silybin. In our in silico study we showed that silychristin and silybin have conformations which interact with the active COX site as competitive inhibitors, blocking the possibility of substrate binding. Conclusions The results obtained from this study clearly present the potential of flavonolignans as novel antiplatelet and anti-inflammatory agents.

2,3-Dehydrosilybin (DHS) was previously shown to chelate and reduce both copper and iron ions. In this study, similar experiments with 2,3-dehydrosilychristin (DHSCH) showed that this congener of DHS also chelates and reduces both metals. Statistical analysis pointed to some differences between both compounds: in general, DHS appeared to be a more potent iron and copper chelator, and a copper reducing agent under acidic conditions, while DHSCH was a more potent copper reducing agent under neutral conditions. In the next step, both DHS and DHSCH were tested for metal-based Fenton chemistry in vitro using HPLC with coulometric detection. Neither of these compounds were able to block the iron-based Fenton reaction and, in addition, they mostly intensified hydroxyl radical production. In the copper-based Fenton reaction, the effect of DHSCH was again prooxidant or neutral, while the effect of DHS was profoundly condition-dependent. DHS was even able to attenuate the reaction under some conditions. Interestingly, both compounds were strongly protective against the copper-triggered lysis of red blood cells, with DHSCH being more potent. The results from this study indicated that, notwithstanding the prooxidative effects of both dehydroflavonolignans, their in vivo effect could be protective.

• Milk thistle has a potent potential to tyrosinase inhibition. • First report on full characterization of tyrosinase inhibition by silymarin. • A long prolongation of lag time indicated that silymarin formed E met ·I effectively. • Tyrosinase inhibition of silymarin was doubly confirmed by HPLC analysis. Anti-melanogenesis effects of silymarin from milk thistle have been reported recently, but detailed tyrosinase inhibition properties of individual components have not been investigated. This study purported to substantiate tyrosinase inhibition and its mechanism based on a single metabolite. The responsible components for tyrosinase inhibition of target source were found out as flavonolignans which consist of isosilybin A (1), isosilybin B (2), silydianin (3), 2,3-dihydrosilychristin (4), silychristin A (5), silychristin B (6) and silybin (7), respectively. The isolated flavonolignans (1 – 7) inhibited both monophenolase (IC 50 = 1.7–7.6 µM) and diphenolase (IC 50 = 12.1–44.9 µM) of tyrosinase significantly. Their inhibitions were 10-fold effective in comparison with their mother skeletons (8 – 10). Inhibitory functions were also proved by HPLC analysis using N -acetyl- l -tyrosine as substrate. The predominant formation of E met ·I was confirmed from a long prolongation of lag time and a decrease of the static state activity of the enzyme. All tested compounds had a significant binding affinity to tyrosinase with K SV values of 0.06–0.27 × 104 L·mol−1, which are well correlated with IC 50 s. In kinetic study, all flavonolignan (1 – 7) were mixed type I (K I < K IS) inhibitors, whereas their mother skeletons (8 – 10) were competitive ones. The UPLC-ESI-TOF/MS analysis showed that the isolated inhibitors are the most abundant metabolites in the target plant. [ABSTRACT FROM AUTHOR]

Background: In recent years the number of natural products used as pharmaceuticals, components of dietary supplements and cosmetics has increased tremendously requiring more extensive evaluation of their pharmacokinetic properties.Purpose: This study aims at combining in vitro and in silico methods to evaluate the gastrointestinal absorption (GIA) of natural flavonolignans from milk thistle (Silybum marianum (L.) Gaertn.) and their derivatives.Methods: A parallel artificial membrane permeability assay (PAMPA) was used to evaluate the transcellular permeability of the plant main components. A dataset of 269 compounds with measured PAMPA values and specialized software tools for calculating molecular descriptors were utilized to develop a quantitative structure-activity relationship (QSAR) model to predict PAMPA permeability.Results: The PAMPA permeabilities of 7 compounds constituting the main components of the milk thistle were measured and their GIA was evaluated. A freely-available and easy to use QSAR model predicting PAMPA permeability from calculated physico-chemical molecular descriptors was derived and validated on an external dataset of 783 compounds with known GIA. The predicted permeability values correlated well with obtained in vitro results. The QSAR model was further applied to predict the GIA of 31 experimentally untested flavonolignans.Conclusions: According to both in vitro and in silico results most flavonolignans are highly permeable in the gastrointestinal tract, which is a prerequisite for sufficient bioavailability and use as lead structures in drug development. The combined in vitro/in silico approach can be used for the preliminary evaluation of GIA and to guide further laboratory experiments on pharmacokinetic characterization of bioactive compounds, including natural products. [ABSTRACT FROM AUTHOR]

Selection of milk thistle (Silybum marianum (L.) Gaertn.) genotypes for commercial cultivation depends on wild population resources, rather than on selection of varieties. The evaluation of these populations could contribute to the development of new milk thistle varieties with desirable traits such as high silymarin content. Therefore, we conducted a study to evaluate 30 wild populations occurring naturally in Greece, based on seed silymarin content. Seeds were collected from populations growing in localities presenting different environmental conditions. In addition, we also investigated the diversity in levels of silymarin constituents, as well as observed correlations among them. Significant differences in silymarin content were recorded among the populations studied, with values ranging from 2.31 to 7.71% (avg. 3.31%), as well as in flavonolignan and taxifolin content. The mean taxifolin content was 4.96 mg/g, while the highest silybin A + silybin B content (21.77–31.39 mg/g of dry weight (dw)) was recorded in seeds from the "Spata" population originating from central Greece. Our results showed noticeable levels of diversity in silymarin content and composition in native milk thistle populations, indicating that a valuable gene pool for exploitation in milk thistle breeding programmes exists in Greece. Selection of milk thistle genotypes for commercial cultivation depends on wild population resources. The evaluation of these populations could contribute to the development of new milk thistle varieties with desirable traits. Therefore, we conducted a study to evaluate 30 wild populations growing in Greece. Significant differences in silymarin content were recorded among the populations studied, with values ranging from 2.31 to 7.71%, as well as in flavonolignan and taxifolin content. Our results showed noticeable levels of diversity in silymarin content, indicating that a valuable gene pool for exploitation in milk thistle breeding programmes exists in Greece. [ABSTRACT FROM AUTHOR]

Supercritical fluid extraction with carbon dioxide is nowadays one of the best approaches on an economic and ecological point of view for the extraction of natural compounds from plants. Besides, many seeds or fruits contain both lipids, as triglycerides, which can be used for food or cosmetic industries, and polyphenols which do have many bioprotective effects for the human health. By using successively pure carbon dioxide and carbon dioxide added with a polar modifier, either pure ethanol or a ethanol/water mixture, we achieved first the extraction of triglycerides of the milk thistle seeds, followed by the extraction of the flavonolignans, which are bioactive compounds. Effects of pressure (15 and 25 MPa) and temperature (40 and 60 °C) were studied on the lipids extraction efficiency. For flavonolignans, the polar compounds, the impact of modifier amount (pure ethanol from 10% to 40%) and water percentage in ethanol (5–15%) were compared. The duration of the two sequential steps to achieve the complete seed defatting and to increase the flavonolignan recovery were also studied. The complete lipids extraction was achieved with pure CO2 at 40 °C, 25 MPa for 30 min whereas the extraction of flavonolignans was achieved with 20% of modifier (wate/ethanol 15/85) during 90 min. The analysis of the triglyceride composition of milk thistle seed were studied by using supercritical fluid chromatography (SFC), whereas the analysis of flavonolignans was carried out by an improved Ultra-high-pressure liquid chromatography (UHPLC) method. [Display omitted] • Selective sequential supercritical fluid extraction applied on Milk Thistle seeds. • Supercritical fluid chromatography for the TG analysis of Milk Thistle. • Study of the defatting and the supercritical extraction of flavonolignans. [ABSTRACT FROM AUTHOR]

Dandelion (Taraxacum officinale L.) roots, leaves, and flowers have a long history of use in traditional medicine. Compared to the above organs, dandelion fruits are the least known and used. Hence, the present paper was aimed at the phytochemical analysis of T. officinale fruit extract and estimating its antiradical, antiplatelet, and antioxidant properties related to hemostasis. Methanolic extract of fruits (E1), enriched with polyphenols (188 mg gallic acid equivalents (GAE)/g), was successfully separated into cinnamic acids (E2; 448 mg GAE/g) and flavonoids (E3; 377 mg GAE/g) extracts. Flavonoid extract was further divided into four fractions characterized by individual content: A (luteolin fraction; 880 mg GAE/g), B (philonotisflavone fraction; 516 mg GAE/g), C (flavonolignans fraction; 384 mg GAE/g), and D (flavone aglycones fraction; 632 mg GAE/g). High DPPH radical scavenging activity was evaluated for fractions A and B (A > B > Trolox), medium for extracts (Trolox > E3 > E2 > E1), and low for fractions C and D. No simple correlation between polyphenol content and antiradical activity was observed, indicating a significant influence of qualitative factor, including higher anti-oxidative effect of flavonoids with B-ring catechol system compared to hydroxycinnamic acids. No cytotoxic effect on platelets was observed for any dandelion preparation tested. In experiments on plasma and platelets, using several different parameters (lipid peroxidation, protein carbonylation, oxidation of thiols, and platelet adhesion), the highest antioxidant and antiplatelet potential was demonstrated by three fruit preparations–hydroxycinnamic acids extract (E2), flavonoid extract (E3), and luteolin fraction (A). The results of this paper provide new information on dandelion metabolites, as well as their biological potential and possible use concerning cardiovascular diseases.

Flavonolignans occur typically in Silybum marianum (milk thistle) fruit extract, silymarin, which contains silybin, isosilybin, silychristin, silydianin, and their 2,3-dehydroderivatives, together with other minor flavonoids and a polymeric phenolic fraction. Biotransformation of individual silymarin components by human microbiota was studied ex vivo, using batch incubations inoculated by fecal slurry. Samples at selected time points were analyzed by ultrahigh-performance liquid chromatography equipped with mass spectrometry. The initial experiment using a concentration of 200 mg/L showed that flavonolignans are resistant to the metabolic action of intestinal microbiota. At the lower concentration of 10 mg/L, biotransformation of flavonolignans was much slower than that of taxifolin, which was completely degraded after 16 h. While silybin, isosilybin, and 2,3-dehydrosilybin underwent mostly demethylation, silychristin was predominantly reduced. Silydianin, 2,3-dehydrosilychristin and 2,3-dehydrosilydianin were reduced, as well, and decarbonylation and cysteine conjugation proceeded. No low-molecular-weight phenolic metabolites were detected for any of the compounds tested. Strong inter-individual differences in the biotransformation profile were observed among the four fecal-material donors. In conclusion, the flavonolignans, especially at higher (pharmacological) doses, are relatively resistant to biotransformation by gut microbiota, which, however, depends strongly on the individual structures of these isomeric compounds, but also on the stool donor.

Herbal preparations from Silybum marianum have been used since the fourth century BC in liver disease treatment and against numerous other pathologies. Consumption of silymarin containing drugs and food supplements continues to increase. Precise, fast, reliable, and complex determination of all components of silymarin preparations is paramount for assessing its pharmacological quality. We present here simple and fast HPLC-DAD and LC-MS analytical methods for the determination and quantification of all known silymarin components, including 2,3-dehydroflavonolignans that has not been achieved so far. The first method, using a common C18 column, allows baseline separation of previously inseparable silychristin A, B, isosilychristin, and silydianin. Moreover, this method allowed detection of three so far unknown silymarin components. In addition, the first analytical separation of enantiomers of 2,3-dehydrosilybin was achieved using a Lux 3μ Cellulose-4 chiral column, providing even more accurate description of silymarin composition. 2,3-Dehydroflavonolignans were isolated for the first time from silymarin using preparative chromatography on C18 and ASAHIPAK columns, and 2,3-dehydrosilychristin and 2,3-dehydrosilybin were for the first time conclusively confirmed by HPLC, MS, and NMR to be silymarin components. Using the optimized analytical methods, six various silymarin preparations were analyzed showing substantial differences in the composition.

Background and objectives: Silymarin is a unique flavonoid complex with documented hepatoprotective properties. Silybum marianum hairy root culture as a source for producing silymarin has been an important strategy for study the cell signaling pathway. In the present investigation Trichoderma strains- Silybum marianum hairy root cultures interactions have been studied. Methods: The effects of two Trichoderma Strains (KHB and G46-7) (0, 0.5, 1, 2 and 4 mg/ 50 mL culture) in 6 different exposure times (0, 24, 48, 72, 96 and 120 h) have been investigated on flavonolignans production. The flavonolignans were analyzed by High Performance Liquid Chromatography method. Cell signaling pathway was evaluated by determination of H2O2 content, peroxidase and ascorbate peroxidase activities. Results:The elicitation effects of two Trichoderma Strains (KHB and G46-7) were examined on flavonolignans accumulation and the activation of cell defense system in S. marianum hairy root cultures. The results indicated that the highest silymarin accumulation (0.45 and 0.33 mg/g DW) was obtained in media elicited with 0.5 mg/50 mL cultures of T. harzianum Strains (KHB and G46-3, respectively) after 120 h. Feeding time experiments indicated that a significant higher content of silymarin production was achieved after 120 and 72 h in media treated with 0.5 mg/50 mL cultures of KHB and G46-3, respectively. Our results showed that S. marianum treated by KHB strain, increased taxifolin, silychristin, isosilybin and silydianin productions significantly. The H2O2 content in the control hairy root cultures remained lower than the treated cultures. There was significant enhancement in both peroxidase and ascorbate peroxidase activities in treated hairy roots reaching a peak after 72 h. Conclusion: These findings suggested that some Trichoderma strains are positive elicitors for promoting silymarin accumulation in S. marianum hairy root cultures. The results also suggested the presence of H2O2 and oxidative burst induced by T. harzianum as a signaling pathway.

The physicochemical properties of classical lignans, neolignans, flavonolignans and carbohydrate-lignan conjugates (CLCs) were analysed to assess their ADMET profiles and establish if these compounds are lead-like/drug-like and thus have potential to be or act as leads in the development of future therapeutics. It was found that while no studied compounds were lead-like, a very large proportion (>75%) fulfilled all the requirements to be deemed as present in drug-like space and almost all compounds studied were in the known drug space. Principal component analysis was an effective technique that enabled the investigation of the relationship between the studied molecular descriptors and was able to separate the lignans from their sugar derivatives and flavonolignans, primarily according to the parameters that are considered when defining chemical space (i.e., number of hydrogen bond donors, acceptors, rotatable bonds, polar surface area and molecular weight). These results indicate that while CLCs and flavonolignans are less drug-like, lignans show a particularly high level of drug-likeness, an observation that coupled with their potent biological activities, demands future pursuit into their potential for use as therapeutics. [ABSTRACT FROM AUTHOR]

New silibinin phosphodiester glyco-conjugates were synthesized by efficient phosphoramidite chemistry and were fully characterized by 2D-NMR. A wide-ranging study focused on the determination of their pKa and E ° values as well as on their radical scavenging activities by different assays (DPPH, ABTS + and HRSA) was conducted. The new glyco-conjugates are more water-soluble than silibinin, and their radical scavenging activities are higher than those of silibinin. The conjugation therefore improves both the water solubilities and antioxidant activities of the flavonolignan moieties. The serum stability was evaluated under physiological conditions, and the glyco-conjugates degraded with half-lives of 40–70 h, making them useful in pro-drug approaches. We started by treating androgen-dependent prostate cancer (PCa) LNCaP cells and then expanded our studies to androgen-independent PCa PC3 and DU145 cells. In most cases, the new derivatives significantly reduced both total and live cell numbers, albeit at different levels. Anti-HIV activities were evaluated and the glucosamine-phosphate silibinin derivative showed higher activity (IC 50  = 73 μM) than silibinin. [ABSTRACT FROM AUTHOR]

Adenosine diphosphate (ADP) is the major platelet agonist, which is important in the shape changes, stability, and growth of the thrombus. Platelet activation by ADP is associated with the G protein-coupled receptors P2Y1 and P2Y12. The pharmacologic blockade of the P2Y12 receptor significantly reduces the risk of peripheral artery disease, myocardial infarction, ischemic stroke, and vascular death. Recent studies demonstrated the inhibition of ADP-induced blood platelet activation by three major compounds of the flavonolignans group: silybin, silychristin, and silydianin. For this reason, the aim of the current work was to verify the effects of silybin, silychristin, and silydianin on ADP-induced physiological platelets responses, as well as mechanisms of P2Y12-dependent intracellular signal transduction. We evaluated the effect of tested flavonolignans on ADP-induced blood platelets’ aggregation in platelet-rich plasma (PRP) (using light transmission aggregometry), adhesion to fibrinogen (using the static method), and the secretion of PF-4 (using the ELISA method). Additionally, using the double labeled flow cytometry method, we estimated platelet vasodilator-stimulated phosphoprotein (VASP) phosphorylation. We demonstrated a dose-dependent reduction of blood platelets’ ability to perform ADP-induced aggregation, adhere to fibrinogen, and secrete PF-4 in samples treated with flavonolignans. Additionally, we observed that all of the tested flavonolignans were able to increase VASP phosphorylation in blood platelets samples, which is correlated with P2Y12 receptor inhibition. All of these analyses show that silychristin and silybin have the strongest inhibitory effect on blood platelet activation by ADP, while silydianin also inhibits the ADP pathway, but to a lesser extent. The results obtained in this study clearly demonstrate that silybin, silychristin, and silydianin have inhibitory properties against the P2Y12 receptor and block ADP-induced blood platelet activation. [ABSTRACT FROM AUTHOR]

The primary biological function of platelets is to form hemostatic thrombi that prevent blood loss and maintain vascular integrity. These multi-responding cells are activated by different endogenous, physiological agonists due to the vast number of receptors present on the surface of the platelets. Collagen represents up to 40% of the total protein presented in the vessel wall and is the major activator of the platelets’ response after tissue injury, and is the only matrix protein which supports both platelet adhesion and complete activation. The aim of our study was to determine the effects of three major flavonolignans (silybin, silychristin and silydianin) on collagen-induced blood platelets’ activation, adhesion, aggregation and secretion of PF-4. We observed that depending on the dose, silychristin and silybin have anti-platelet properties observed as inhibition of collagen-induced activation (formation of blood platelet aggregates and microparticles, as well as decreased expression of P-selectin and activation of integrin α IIb β 3 ), aggregation, adhesion and secretion of PF-4. These effects highlight the potential of silybin and silychristin as supplementation to prevent primary and secondary thrombotic events wherein excessive blood platelet response to a physiological agonist is observed. [ABSTRACT FROM AUTHOR]

• Sequential supercritical fluid extraction of non-polar and polar compounds. • On-line supercritical fluid chromatography analysis of both fractions. • Transfer loop facilitates independent extraction and chromatographic steps. • Transfer loop is best suited to polar fractions than on-column transfer. • Transfer loop allows for kinetics study of analysis of optimized extract. Plant seeds, as those from milk thistle (Silybum marianum), are a valuable source of nonpolar and polar compounds with potentially interesting biological activity. The main nonpolar compounds are triglycerides, which are also the main components of all vegetable oils. In addition, specific polar compounds – flavonolignans, called silymarin, have been found in large amounts in milk thistle seeds extract. These flavonoids derivatives have different biological activity, for instance hepatoprotective effects. In order to extract and analyze both nonpolar (triglycerides) and polar compounds (flavonolignans) from milk thistle seeds through a sequential methodology, an on-line supercritical fluid extraction - supercritical fluid chromatography (SFE-SFC) method was developed. Different ways of transferring the extracts from SFE to SFC (i.e. direct on-column transfer and loop transfer) were compared, and particularly for their effect on chromatographic quality. In this respect, nonpolar and polar compounds caused different issues, especially as polar compounds required a significant portion of co-solvent in the extraction step, favoring early elution in the chromatographic column. First, on-line SFE-SFC was used for triglycerides analysis and allowed the comparison of transfer modes. Then, on-line kinetics were performed to measure defatting time before polar molecules extraction. Finally, the eventual benefit of loop transfer was also investigated for the analysis of flavonolignans, polar molecules whose analysis can be difficult by on-line SFE-SFC. The aim of this paper is to discuss the versatility of on-line SFE-SFC and how challenging the coupling can be, especially when both non-polar and polar molecules must be analyzed independently in a single sample. [ABSTRACT FROM AUTHOR]

Elicitation with middle-viscous chitosan (30 mg/50 mL) significantly stimulated silymarin synthesis in Silybum marianum hairy root cultures. The root cultures established by infection with Agrobacterium rhizogenes AR15834 showed a potential for production of silymarin. Elicitation with medium molecular weight of chitosan (0, 5, 10, 20, and 30 mg/50 mL) was used in order to improve silymarin production. Total silymarin increased about 5.26-fold after 96 h of treatment with 30 mg/50 mL chitosan. Dry weight of the hairy roots reached the highest point (0.530 and 0.535 g) after 96 h in presence of 20 and 30 mg/50 mL chitosan, respectively. Five different flavonolignans were isolated; taxifolin, silychristin, silydianin, silybin and isosilybin) 0.133, 0.200, 0.120, 0.041 and 0.056 mg/g dry weight, respectively). 30 days old hairy roots were treated by 30 mg/50 mL chitosan in different times (12, 24, 48, 72, 96 and 120 h). The amount of silymarin accumulation significantly increased (0.705 mg/gDW) in hairy roots after 96 h treatment. These observations suggested that the medium molecular weight of chitosan could be elicited by S. marianum hairy root cultures that lead to the higher production of silymarin. These results correlated with the culture time, and the biosynthesis which reached to a maximum of 0.705 mg/gDW by 96 h after culture. (2.9-fold higher than the control).

Milk thistle (Silybum marianum (L.) Gaertn.) is a promising new crop in the Mediterranean region. Its seeds contain silymarin, a complex of flavonolignans, which is widely used in the pharmaceutical industry, mainly to produce dietary supplements. To meet the increasing demand for milk thistle, the production and productivity of milk thistle should also be optimized by employing adequate cultivation practices. In the present study, a two-year field experiment was conducted to assess the effects of plant density and a plant growth regulator on milk thistle crop growth, seed yield, and silymarin accumulation under Mediterranean semi-arid conditions. Our results showed that plant density had a significant impact on milk thistle crop growth and seed yield. The main crop characteristics, such as height, aboveground biomass, and seed yield were greatest when plant density was the highest. Increased plant density significantly reduced the silymarin content only in 2018. In contrast, mepiquat chloride (MC) treatment did not affect the following traits: plant biomass, relative chlorophyll content, silymarin content, and production. Nevertheless, mepiquat chloride reduced the plant height by 7.9−14.8%, depending on the application rates and growth conditions. Moreover, the impact of climatic conditions on milk thistle production and quality was significant, since the lowest values of silymarin content and seed yield were recorded in the year with drought conditions during the period from March to May.

Silybum marianum (L.) Gaertn. (aka milk thistle) constitutes the source of silymarin (SILM), a mixture of different flavonolignans and represents a unique model for their extraction. Here we report on the development and validation of an ultrasound-assisted extraction (UAE) method of S. marianum flavonolignans follow by their quantification using LC system. The optimal conditions of this UAE method were: aqueous EtOH 54.5% (v/v) as extraction solvent, with application of an ultrasound (US) frequency of 36.6 kHz during 60 min at 45 °C with a liquid to solid ratio of 25:1 mL/g dry weight (DW). Following its optimization using a full factorial design, the extraction method was validated according to international standards of the association of analytical communities (AOAC) to ensure precision and accuracy in the quantitation of each component of the SILM mixture. The efficiency of this UAE was compared with maceration protocol. Here, the optimized and validated conditions of the UAE allowed the highest extraction yields of SILM and its constituents in comparison to maceration. During UAE, the antioxidant capacity of the extracts was retained, as confirmed by the in vitro assays CUPRAC (cupric ion reducing antioxidant capacity) and inhibition of AGEs (advanced glycation end products). The skin anti-aging potential of the extract obtained by UAE was also confirmed by the strong in vitro cell-free inhibition capacity of both collagenase and elastase. To summarize, the UAE procedure presented here is a green and efficient method for the extraction and quantification of SILM and its constituents from the fruits of S. marianum, making it possible to generate extracts with attractive antioxidant and anti-aging activities for future cosmetic applications.

Antioxidants protect the structural and functional components in organisms against oxidative stress. Most antioxidants are of plant origin as the plants are permanently exposed to oxidative stress (UV radiation, photosynthetic reactions). Both carotenoids and flavonoids are prominent antioxidant and anti-radical agents often occurring together in the plant tissues and acting in lipophilic and hydrophilic milieu, respectively. They are complementary in their anti-radical activity. This study describes the synthesis of a series of hybrid ester conjugates of retinoic acid with various flavonolignans, such as silybin, 2,3-dehydrosilybin and isosilybin. Antioxidant/anti-radical activities and bio-physical properties of novel covalent carotenoid-flavonoid hybrids, as well as various mixtures of the respective parent components, were investigated. Retinoyl conjugates with silybin—which is the most important flavonolignan in silymarin complex—(and its pure diastereomers) displayed better 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than both the parent compounds and their equimolar mixtures.