Clinical applications of Silybum marianum in oncology

Effect of Silybum Marianum on Reduction of Chemotherapy-Induced Peripheral Neurotoxicity with Cisplatin

Background

Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of the major complications of chemotherapy regimens commonly used in the treatment of solid and hematologic cancers. Given the high incidence of CIPN in antitumor therapies in patients and limited studies on antioxidants, this study was aimed to investigate the effect of Silybum marianum (SM) on cisplatin-induced peripheral neuropathy.

Materials and Methods

This double-blind randomized clinical trial study was performed on 60 cancer patients treated with cisplatin chemotherapy at Seyyed-o-Shohada Hospital of Isfahan during 2019-2020. The patients were divided into two parallel groups as intervention (treated by SM) and placebo, and DN4 (Douleur neuropathique 4 questions) and CIPNAT (chemotherapy-induced peripheral neuropathy assessment tool) were completed for patients in the before and after intervention groups and compared between the two groups.

Results

The mean of DN4 score in the before and after study in the intervention group was in 1.76 ± 1.24 and 2.07 ± 2.03, respectively (P = 0.38), and in the control group was 1.41 ± 1.28 ± 3.11 ± 2.86, respectively (P = 0.012). The mean CIPNAT score in the intervention groups was 5.93 ± 3.65 and 4.20 ± 3.23 (P = 0.01), and in the control group was 4.20 ± 4.22 and 4.16 ± 4.03 (P = 0.39).

Conclusion

Based on our data, SM is an effective agent in reducing peripheral neuropathy. The use of SM was associated with decreased scores of peripheral neuropathy and was helpful in patients undergoing chemotherapy with cisplatin.

Genetic activity and cytotoxic effect of Silybum marianum extract in comparison with the impact of antitumor drugs etoposide and methotrexate: a study on Drosophila melanogaster

One of the most important directions in medical practice involves the exploration of protectors and adaptogens to mitigate side effects associated with the use of antitumor and potent medications. The extracts of medicinal plants are actively tested as protectors. In connection with this, the aim of the research was to determine the effectiveness of the protective properties of Silybum marianum extract against the drugs 'etoposide' and 'methotrexate' at concentrations of 800 μg/kg using the model object Drosophila melanogaster. To analyse the protective properties, the following research methods were applied: determining the lethal concentration, average individual fertility of individuals, mortality of F1 offspring at embryonic stages, SMART (a method for determining the frequency of somatic mutations and recombinations) and assessing the intensity of programmed cell death. The study revealed that a 5% S. marianum extract reduces the genotoxicity of etoposide and exhibits a high cytotoxic effect, both independently and in combination with etoposide and methotrexate.

Authentication of milk thistle commercial products using UHPLC-QTOF-ESI + MS metabolomics and DNA metabarcoding

BACKGROUND

Milk thistle is one of the most popular hepatoprotectants, and is often sold in combination with other ingredients. Botanical supplements are known to be vulnerable to contamination and adulteration, and emerging technologies show promise to improve their quality control.

METHODS

Untargeted and semi-targeted metabolomics based on UHPLC-QTOF-ESI⁺MS techniques, UV spectrometry, and DNA metabarcoding using Illumina MiSeq were used to authenticate eighteen milk thistle botanical formulations (teas, capsules, tablets, emulsion).

RESULTS

Untargeted metabolomics separated 217 molecules and by multivariate analysis the discrimination between the different preparations was established. The semi-targeted metabolomics focused on 63 phytochemicals, mainly silymarin flavonolignans and flavonoids, that may be considered as putative biomarkers of authenticity. All formulations contained molecules from silymarin complexes at different levels. The quantitative evaluation of silybins was done using in parallel UV spectrometry and UHPLC-QTOF-ESI⁺MS and their correlations were compared. DNA metabarcoding detected milk thistle in eleven out of sixteen retained preparations, whereas two others had incomplete evidence of milk thistle despite metabolomics validating specific metabolites, e.g., silymarin complex, identified and quantified in all samples. Meanwhile, the DNA metabarcoding provided insights into the total species composition allowing the interpretation of the results in a broad context.

CONCLUSION

Our study emphasizes that combining spectroscopic, chromatographic, and genetic techniques bring complementary information to guarantee the quality of the botanical formulations.

Biodegradable hydrogel from pectin and carboxymethyl cellulose with Silibinin loading for lung tumor therapy

Serious side effects of chemotherapy drugs greatly limited the anticancer performance, while targeted drug delivery could improve the therapeutic effect and reduce side effects. In this work, biodegradable hydrogel was fabricated from pectin hydrazide (pec-H) and oxidized carboxymethyl cellulose (DCMC) for localized Silibinin delivery in lung adenocarcinoma treatment. The self-healing pec-H/DCMC hydrogel showed blood compatibility and cell compatibility both in vitro and in vivo, and could be degraded by enzymes. The hydrogel also formed fast fit for injectable applications and showed sustained drug release characteristic sensitive to pH based on acylhydrzone bond cross-linked networks. The Silibinin, as a specific lung cancer inhibiting drug targets TMEM16A ion channel, was loaded into the pec-H/DCMC hydrogel to treat the lung cancer in mice model. The results showed that the hydrogel loaded Silibinin significantly enhanced the anti-tumor efficiency in vivo and greatly reduced the toxicity of the Silibinin. Based on the dual effect of improving efficacy and reducing side effects, the pec-H/DCMC hydrogel with Silibinin loading have broad application prospects to inhibit lung tumor growth in clinic.

Detecting and Profiling of Milk Thistle Metabolites in Food Supplements: A Safety-Oriented Approach by Advanced Analytics

Milk thistle (Silybum marianum (L.) Gaertn.) is among the top-selling botanicals used as a supportive treatment for liver diseases. Silymarin, a mixture of unique flavonolignan metabolites, is the main bioactive component of milk thistle. The biological activities of silymarin have been well described in the literature, and its use is considered safe and well-tolerated in appropriate doses. However, commercial preparations do not always contain the recommended concentrations of silymarin, failing to provide the expected therapeutic effect. While the poor quality of raw material may explain the low concentrations of silymarin, its deliberate removal is suspected to be an adulteration. Toxic contaminants and foreign matters were also detected in milk thistle preparations, raising serious health concerns. Standard methods for determination of silymarin components include thin-layer chromatography (TLC), high-performance thin-layer chromatography (HPTLC), and high-performance liquid chromatography (HPLC) with various detectors, but nuclear magnetic resonance (NMR) and ultra-high-performance liquid chromatography (UHPLC) have also been applied. This review surveys the extraction techniques of main milk thistle metabolites and the quality, efficacy, and safety of the derived food supplements. Advanced analytical authentication approaches are discussed with a focus on DNA barcoding and metabarcoding to complement orthogonal chemical characterization and fingerprinting of herbal products.

Apigenin Isolated from Carduus crispus Protects against H2O2-Induced Oxidative Damage and Spermatogenic Expression Changes in GC-2spd Sperm Cells

Testicular oxidative stress is one of the most common factors underlying male infertility. Welted thistle, Carduus crispus Linn., and its bioactive principles are attracting scientific interest in treating male reproductive dysfunctions. Here, the protective effects of apigenin isolated from C. crispus against oxidative damage induced by hydrogen peroxide (H2O2) and dysregulation in spermatogenesis associated parameters in testicular sperm cells was investigated. Cell viabilities, ROS scavenging effects, and spermatogenic associated molecular expressions were measured by MTT, DCF-DA, Western blotting and real-time RT-PCR, respectively. A single peak with 100% purity of apigenin was obtained in HPLC conditions. Apigenin treated alone (2.5, 5, 10 and 20 µM) did not exhibit cytotoxicity, but inhibited the H2O2-induced cellular damage and elevated ROS levels significantly (p < 0.05 at 5, 10 and 20 µM) and dose-dependently. Further, H2O2-induced down-regulation of antioxidant (glutathione S-transferases m5, glutathione peroxidase 4, and peroxiredoxin 3) and spermatogenesis-associated (nectin-2 and phosphorylated-cAMP response element-binding protein) molecular expression in GC-2spd cells were attenuated by apigenin at both protein and mRNA levels (p < 0.05). In conclusion, our study showed that apigenin isolated from C. crispus might be an effective agent that can protect ROS-induced testicular dysfunctions.

Natural Compounds for Counteracting Nonalcoholic Fatty Liver Disease (NAFLD): Advantages and Limitations of the Suggested Candidates

The booming prevalence of nonalcoholic fatty liver disease (NAFLD) in adults and children will threaten the health system in the upcoming years. The "multiple hit" hypothesis is the currently accepted explanation of the complex etiology and pathophysiology of the disease. Some of the critical pathological events associated with the development of NAFLD are insulin resistance, steatosis, oxidative stress, inflammation, and fibrosis. Hence, attenuating these events may help prevent or delay the progression of NAFLD. Despite an increasing understanding of the mechanisms involved in NAFLD, no approved standard pharmacological treatment is available. The only currently recommended alternative relies on lifestyle modifications, including diet and physical activity. However, the lack of compliance is still hampering this approach. Thus, there is an evident need to characterize new therapeutic alternatives. Studies of food bioactive compounds became an attractive approach to overcome the reticence toward lifestyle changes. The present study aimed to review some of the reported compounds with beneficial properties in NAFLD; namely, coffee (and its components), tormentic acid, verbascoside, and silymarin. We provide details about their protective effects, their mechanism of action in ameliorating the critical pathological events involved in NAFLD, and their clinical applications.

Silymarin: not just another antioxidant

Silymarin (Silybum marianum; SM), popularly known as milk thistle, is an extract that has been used for many centuries to treat liver diseases. In recent years, several studies have shown that SM is not only just another antioxidant but also a multifunctional compound that exhibits several beneficial properties for use in the treatment and prevention of different types of pathologies and disorders. This review aims at demonstrating the main protective activities of SM in diseases, such as cancer, diabetes, hepatitis, non-alcoholic fatty liver disease, alcoholic liver disease, hepatitis C virus, hepatitis B virus, metabolic syndrome, depression, cardiovascular diseases and thalassemia, in addition to its photoprotective activity in in vitro tests and preclinical studies. Its main functions include antioxidant and anti-inflammatory effects, and it acts as modulator of signaling pathways. It has been suggested that SM presents great multifunctional potential and is capable of achieving promising results in different types of research. However, caution is still needed regarding its indiscriminate use in humans as there are only a few clinical studies relating to the adequate dose and the actual efficacy of this extract in different types of diseases.

Flavonolignans: One Step Further in the Broad-Spectrum Approach of Cancer

BACKGROUND

The small chemical class of flavonolignans encompasses unique hybrid molecules with versatile biological activities. Their anticancer effects have received considerable attention, and a large body of supporting evidence has accumulated. Moreover, their ability to interact with proteins involved in drug resistance, and to enhance the effects of conventional chemotherapeutics in decreasing cell viability make them influential partners in addressing cancer.

OBJECTIVE

The review provides an outline of the various ways in which flavonolignans advance the combat against cancer. While the main focus falls on flavonolignans from milk thistle, attention is drawn to the yet, underexplored potential of less known flavonolignan subgroups derived from isoflavonoids and aurones.

METHODS

Proceeding from the presentation of natural flavonolignan subtypes and their occurrence, the present work reviews these compounds with regard to their molecular targets in cancer, anti-angiogenetic effects, synergistic efficacy in conjunction with anticancer agents, reversal of drug resistance, and importance in overcoming the side effects of anticancer therapy. Recent advances in the endeavor to improve flavonolignan bioavailability in cancer are also presented.

CONCLUSIONS

Significant progress has been achieved in detailing the molecular mechanisms of silybin and its congeners in experimental models of cancer. The availability of novel formulations with improved bioavailability, and data from phase I clinical trials in cancer patients provide an encouraging basis for more extensive trials aimed at evaluating the benefits of Silybum flavonolignans in cancer management. On the other hand, further research on the antitumor efficacy of iso-flavonolignans and other subtypes of flavonolignans should be pursued.

Silymarin antiproliferative and apoptotic effects: Insights into its clinical impact in various types of cancer

Silymarin is a complex extract isolated from the plant Silybum marianum, widely known for its prominent antioxidant and hepatoprotective effects, although increasing evidences have reported extraordinary antiproliferative and apoptotic abilities. As a result, several signaling pathways involved in cell cycle control, cell proliferation, and cell death have been deconvoluted as critical mechanisms. In this regard, cyclin and cyclin-dependent pathways have been the most studied ones. Following that, apoptotic pathways, such as p53, Akt, STAT-3, Ras, and caspases pathways, have been extensively studied, although other mechanisms involved in inflammation and angiogenesis have also been highlighted as silymarin-likely targets in cancer therapy. Therefore, the main challenge of this review is to discuss the diverse molecular mechanisms for silymarin antiproliferative and apoptotic effects; most of them largely studied in various types of cancers so far. Clinical trials and combination therapies related to silymarin application in cancer prevention and treatment are presented as well.

Escalation of liver malfunctioning: A step toward Herbal Awareness

ETHNOPHARMACOLOGICAL RELEVANCE

About 2-5% of the world's population is suffering from liver toxicity including Pakistan with the second highest rate of hepatitis prevalence. Liver is a vital body organ which not only performs metabolic activities but also aids in detoxification, storage and digestion of food. Now a day's malnutrition, alcohol consumption and drug addiction are major causes of liver diseases throughout the world. In fact, there is no possible outcome to compensate liver malfunction for long term, and transplantation of liver is the only option left after the irretrievable injury of hepatic function. Subsequently, natural based therapeutic approaches are in the process of scrupulous testing as strong hepatoprotective mediator. In this regard plants are well thought hepatoprotective agents having multiple active components. In this review, based on species' pharmacology and safety we have compiled some plants which show strong hepatoprotective activity, main phytoconstituents with biological activities and few commercially used herbal formulations.

MATERIALS AND METHODS

Ethnopharmacological information was gathered by an extensive literature survey like WHO monographs on selected herbal medicinal plants (Vol 1-Vol 4); Principles and Practice of Phytotherapy, Mills S and Bone K, Churchill Livingstone, London, UK; Herbal Drugs and Phytopharmaceuticals, Wichtl M Medpharm Press, Stuttgart 3rd edn; Pharmacology and Applications of Chinese Materia Medica Vols 1 and 2, Chang H-M and But P P-H World Scientific, Singapore; British Herbal Compendium Vol. 2, Bradley P British Herbal Medicine Association, Bournemouth, UK; ESCOP Monographs 2nd edn. Thieme, Stuttgart, Germany; as well as by using electronic databases such as Pubchem, Chemspider, http://www.herbal-ahp.org; http://www.ahpa.org; http://whqlibdoc.who.int/publications/2003/9241546271.pdf; http://www.escop.com, Pubmed, HubMed and Scopus.

RESULTS

Data for more about 29 plants have been accomplished for their bioactive constituent(s), biological activities and medicinal uses. Some of the plants have been identified as strong hepato-modulator. Such knowledge about traditional medicinal plants can be globally applied for safe and evidence based use in pharmacological applications.

CONCLUSION

With the rise in liver risks a meek struggle has been made to draw attention toward herbal therapy. Hepatoprotective constituents of said plants are expressed with chemical structures. However, for certain plants active constituents are not still isolated/purified but overall plant extract was found effective in providing protection against hepatic injury. As a future perspective, there is need to purify plant active constituents for ethnomedical rationale.

Optimization of Microwave-assisted Extraction of Silymarin from Silybum marianum Straws by Response Surface Methodology and Quantification by High-Performance Liquid Chromatograph Method

Background:

Silybum marianum, a member of the Aster family, is a well-known Chinese herb and the source of a popular antioxidant that is extensively used in Asia. The abundant S. marianum straws are still underutilized and wastefully discarded to pollute the environment.

Objective:

To solve the above problem and better utilize S. marianum straws, the objective of this study was to optimize the conditions for extraction of silymarin from S. marianum straws.

Materials and Methods:

A combination of microwave-assisted extraction and response surface methodology (RSM) was used for silymarin from S. marianum straws and yield assessment by high-performance liquid chromatography method. The RSM was based on a five-level, four-variable central composite design (CCD).

Results:

The results indicated that the optimal conditions to obtain highest yields of silymarin were microwave power of 146 W, extraction time of 117 s, liquid-to-solid ratio of 16:1 mL/g, and ethanol concentration of 43% (v/v). Validation tests indicated that under the optimized conditions, the actual yield of silymarin was 6.83 ± 0.57 mg/g with relative standard deviation of 0.92% (n = 5), which was in good agreement with the predicted yield.

Conclusions:

The exploitation of the natural plant resources present very important impact for the economic development. The knowledge obtained from this work should be useful to further exploit and apply this material.

SUMMARY

Silymarin has been isolated from Silybum marianum straws by microwave-assisted extraction and response surface methodology

The results obtained are helpful for the full utilization of S. marianum straws

The microwave-assisted extraction is a very useful method for the extraction of important phytochemicals from plant materials.

Abbreviations used: MAE: Microwave-assisted extraction, RSM: Response surface methodology, HPLC: High-performance liquid chromatography, CCD: Central composite design, ANOVA: Analysis of variance.

Radioprotective effects of Silymarin on the sperm parameters of NMRI mice irradiated with γ-rays

Free radicals and reactive oxygen species (ROS) are generated using various endogenous systems or from external sources such as exposure to different physiochemicals. Ionizing radiation damage to the cell can be caused by the direct or indirect effects of radiotherapy processes. Silymarin (SM), a flavanolignan compound, has been identified as a natural potent antioxidant with cytoprotection activities due to scavenging free radicals. The aim of the present study was to evaluate the radioprotective effect of SM on sperm parameters of mice induced by γ-rays. A total number of 40 adult, male NMRI mice were randomly divided into four equal groups. The control group was neither treated with SM nor irradiated by γ-rays. The second group was only irradiated with 2Gy of γ-rays. The third group was firstly treated with 50mg/kg of SM for 7 consecutive days, and one day later, last injections were irradiated by 2Gy of γ-rays. The fourth groups received only 50mg/kg of SM for 7 consecutive days. All the animals were treated intraperitoneally. Histopathological and morphometrical examinations were performed. The data were analyzed using ANOVA and Tukey post hoc test. A value of p<0.05 was considered significant. The results showed that in the radiation-only group when compared with those treated with SM and irradiated, a significant different was observed in testicular parameters and DNA damage (p<0.05). In conclusion, SM can be considered as a promising herbal radioprotective agent in complementary medicine which may play an important role to protect normal spermatocytes against possible effects of γ-radiation-induced cellular damage.

Effects of Oral Administration of Silymarin in a Juvenile Murine Model of Non-alcoholic Steatohepatitis

The increasing prevalence of non-alcoholic fatty liver disease (NAFLD) in adolescents is challenging the global care system. No therapeutic strategies have been defined so far, and changes in the lifestyle remain the only alternative. In this study, we assessed the protective effects of silymarin in a juvenile non-alcoholic steatohepatitis (NASH) model and the in vitro effects on fat-laden human hepatocytes. C57Bl/6 mice were exposed to HFHC diet immediately after weaning. After eight weeks, animals showed histological signs of NASH. Silymarin was added to the HFHC diet, the treatment continued for additional 12 weeks and the effects on BMI, hepatomegaly, visceral fat, lipid profile, transaminases, HOMA-IR, steatosis, inflammation, fibrosis, oxidative stress, and apoptosis were determined. The switch from HFHC to control diet was used to mimic life style changes. In vitro experiments were performed in parallel in human hepatocytes. HFHC diet supplemented with silymarin showed a significant improvement in glycemia, visceral fat, lipid profile, and liver fibrosis. Moreover, it reduced (both in vitro and in vivo) ALT, hepatic inflammation, oxidative stress, and apoptosis. Lifestyle changes restored the control group parameters. The data presented show the beneficial effects of the oral administration of silymarin in the absence of changes in the dietary habits in a juvenile model of NASH.

Semen quality, antioxidant status and reproductive performance of rabbits bucks fed milk thistle seeds and rosemary leaves

The study aimed to investigate the effects of milk thistle seeds (MTS) and rosemary leaves (RL) both at 5 and 10g/kg diet on reproductive performance, semen quality and blood metabolites of rabbit bucks. A total of 35 rabbit bucks were randomly distributed into five experimental groups (7 bucks/group). All the groups were fed the same basal diet. The 1st group (control) did not have MTS and RL in its basal diet. The 2nd and 3rd groups were supplemented with MTS at 5 and 10g/kg, respectively. The 4th and 5th groups were fed the basal diet supplemented with RL at 5 and 10g/kg, respectively. The sperm concentration (SC), total sperm output (TSO), live sperm (LS), total live sperm (TLS) and total motile sperm (TMS) were significantly greater in the bucks fed MTS at 10 and RL at 5g/kg diet than the control group. Bucks fed MTS at 10g/kg diet had higher fertility than the control. Also, RL 5g/kg group showed higher testosterone and fertility than the control, but the MTS 10g/kg group showed the highest value for both parameters. In conclusion, MTS and RL at 10 and 5g/kg, respectively, significantly improved the semen quality and the fertility and MTS also increased the economic efficiency of rabbit bucks.

Variation in the flavonolignan composition of fruits from different Silybum marianum chemotypes and suspension cultures derived therefrom

Mature fruits collected from different milk thistle (Silybum marianum (L.) Gaertn.) plants, grown in various habitats in Europe, were analysed for silymarin content and variation in component composition. Two different German and Polish cultivars each, as well as fruits from Hungary and Bulgaria have been compared with respect to their ratio of flavonolignan regioisomers. Besides differences in total silymarin content (0.8%-4.9%), three distinct chemotypical variations in fruit flavonolignan regioisomer composition in the cultivars have been observed. Although the differences in the diastereomer ratios of silybin A/B and isosilybin A/B were not significant, they never appeared in a 1:1 ratio. In vitro cultures have been established from seedlings of three typical chemotypes for further insights into flavonolignan content and composition in suspension cultures and the release of these specialized compounds to the extracellular space. The differences in the three Silybum marianum chemotypes were also observed in the composition of the intracellular silymarin of suspension-cultured cells. Silymarin components released to the cell culture medium, however, showed a highly differing composition with only low amounts of silychristin and silydianin. Assays with crude protein extracts prepared from suspension cells or habituated medium of these three chemotypes did not result in differences in silymarin content or composition. In in vitro assays the formation of the regioisomers silydianin and silychristin were strongly influenced by the taxifolin:coniferyl alcohol concentration ratio.

Botanicals and Their Bioactive Phytochemicals for Women's Health

Botanical dietary supplements are increasingly popular for women's health, particularly for older women. The specific botanicals women take vary as a function of age. Younger women will use botanicals for urinary tract infections, especially Vaccinium macrocarpon (cranberry), where there is evidence for efficacy. Botanical dietary supplements for premenstrual syndrome (PMS) are less commonly used, and rigorous clinical trials have not been done. Some examples include Vitex agnus-castus (chasteberry), Angelica sinensis (dong quai), Viburnum opulus/prunifolium (cramp bark and black haw), and Zingiber officinale (ginger). Pregnant women have also used ginger for relief from nausea. Natural galactagogues for lactating women include Trigonella foenum-graecum (fenugreek) and Silybum marianum (milk thistle); however, rigorous safety and efficacy studies are lacking. Older women suffering menopausal symptoms are increasingly likely to use botanicals, especially since the Women's Health Initiative showed an increased risk for breast cancer associated with traditional hormone therapy. Serotonergic mechanisms similar to antidepressants have been proposed for Actaea/Cimicifuga racemosa (black cohosh) and Valeriana officinalis (valerian). Plant extracts with estrogenic activities for menopausal symptom relief include Glycine max (soy), Trifolium pratense (red clover), Pueraria lobata (kudzu), Humulus lupulus (hops), Glycyrrhiza species (licorice), Rheum rhaponticum (rhubarb), Vitex agnus-castus (chasteberry), Linum usitatissimum (flaxseed), Epimedium species (herba Epimedii, horny goat weed), and Medicago sativa (alfalfa). Some of the estrogenic botanicals have also been shown to have protective effects against osteoporosis. Several of these botanicals could have additional breast cancer preventive effects linked to hormonal, chemical, inflammatory, and/or epigenetic pathways. Finally, although botanicals are perceived as natural safe remedies, it is important for women and their healthcare providers to realize that they have not been rigorously tested for potential toxic effects and/or drug/botanical interactions. Understanding the mechanism of action of these supplements used for women's health will ultimately lead to standardized botanical products with higher efficacy, safety, and chemopreventive properties.

Food-based natural products for cancer management: Is the whole greater than the sum of the parts?

The rise in cancer incidence and mortality in developing countries together with the human and financial cost of current cancer therapy mandates a closer look at alternative ways to overcome this burgeoning global healthcare problem. Epidemiological evidence for the association between cancer and diet and the long latency of most cancer progression have led to active exploration of whole and isolated natural chemicals from different naturally occurring substances in various preclinical and clinical settings. In general the lack of systemic toxicities of most 'whole' and 'isolated' natural compounds, their potential to reduce toxic doses and potential to delay the development of drug-resistance makes them promising candidates for cancer management. This review article examines the suggested molecular mechanisms affected by these substances focusing to a large extent on prostate cancer and deliberates on the disparate results obtained from cell culture, preclinical and clinical studies in an effort to highlight the use of whole extracts and isolated constituents for intervention. As such these studies underscore the importance of factors such as treatment duration, bioavailability, route of administration, selection criteria, standardized formulation and clinical end points in clinical trial design with both entities. Overall lack of parallel comparison studies between the whole natural products and their isolated compounds limits decisive conclusions regarding the superior utility of one over the other. We suggest the critical need for rigorous comparative research to identify which one of the two or both entities from nature would be best qualified to take on the mantle of cancer management.

Optimization and single-laboratory validation of a method for the determination of flavonolignans in milk thistle seeds by high-performance liquid chromatography with ultraviolet detection

Seeds of milk thistle, Silybum marianum (L.) Gaertn., are used for treatment and prevention of liver disorders and were identified as a high priority ingredient requiring a validated analytical method. An AOAC International expert panel reviewed existing methods and made recommendations concerning method optimization prior to validation. A series of extraction and separation studies were undertaken on the selected method for determining flavonolignans from milk thistle seeds and finished products to address the review panel recommendations. Once optimized, a single-laboratory validation study was conducted. The method was assessed for repeatability, accuracy, selectivity, LOD, LOQ, analyte stability, and linearity. Flavonolignan content ranged from 1.40 to 52.86% in raw materials and dry finished products and ranged from 36.16 to 1570.7 μg/mL in liquid tinctures. Repeatability for the individual flavonolignans in raw materials and finished products ranged from 1.03 to 9.88% RSDr, with HorRat values between 0.21 and 1.55. Calibration curves for all flavonolignan concentrations had correlation coefficients of >99.8%. The LODs for the flavonolignans ranged from 0.20 to 0.48 μg/mL at 288 nm. Based on the results of this single-laboratory validation, this method is suitable for the quantitation of the six major flavonolignans in milk thistle raw materials and finished products, as well as multicomponent products containing dandelion, schizandra berry, and artichoke extracts. It is recommended that this method be adopted as First Action Official Method status by AOAC International.

Effects of aqueous extract from Silybum marianum on adenosine deaminase activity in cancerous and noncancerous human gastric and colon tissues

Objective:

Investigation of possible effects of Silybum marianum extract (SME) on adenosine deaminase (ADA) activity in cancerous and noncancerous human gastric and colon tissues to obtain information about possible mechanism of anticancer action of S. marianum.

Materials and Methods:

Cancerous and noncancerous human gastric and colon tissues removed from patients by surgical operations were used in the studies. The extract was prepared in distilled water. Before and after treatment with the extract, ADA activities in the samples were measured.

Results:

ADA activity was found to be lowered significantly in cancerous gastric tissues but not in noncancerous gastric tissues after treatment with the SME. In the colon tissues, ADA activities were however found to increase after the treatment of SME.

Conclusion:

Our results suggest that the aqueous extract from S. marianum inhibits ADA activity in cancerous gastric tissues significantly. It is suggested that in addition to other proposed mechanisms, accumulated adenosine due to the inhibition of ADA might also play a part in the anticancer properties of the S. marianum.

The protective effects of silymarin against doxorubicin-induced cardiotoxicity and hepatotoxicity in rats

Silymarin is a complex of five major compounds, and silibinin is the most biologically active component of the complex. The aim of this study was to investigate, evaluate and confirm the potential cardioprotective and hepatoprotective effects of administration of silymarin, rich in silibinin, at a dose of 60 mg/kg orally for a time-span of 12 days on doxorubicin induced toxicity in male Wistar rats. The in vivo model was used to explore whether silymarin could prevent damage of liver and heart tissue induced by doxorubicin administered every other day at dose of 1.66 mg/kg intraperitoneally for twelve days. In the study the change of body weight, ECG changes, biochemical parameters of oxidative stress, serum activity of alanine and aspartate transaminase, lactate dehydrogenase, creatine kinase and histological preparations of heart and liver samples of treated animals were examined. According to physiological, pharmacological, microscopic and biochemical results, we confirmed that at the examined dose, silymarin exhibits a protective influence on the heart and liver tissue against toxicity induced by doxorubicin.

Investigating the potential for toxicity from long-term use of the herbal products, goldenseal and milk thistle

Two-year toxicity studies were conducted on the widely used herbal products, goldenseal and milk thistle, in male and female F344/N rats and B6C3F1 mice. With goldenseal root powder, the primary finding was an increase in liver tumors in rats and mice, and with milk thistle extract, a decrease in spontaneous background tumors including mammary gland tumors in female rats and liver tumors in male mice. Increased tumorigenicity in rodents exposed to goldenseal root powder may be due in part to the topoisomerase inhibition properties of berberine, a major alkaloid constituent in goldenseal, or its metabolite, berberrubine. In the clinic, use of topoisomerase-inhibiting agents has been associated with secondary tumor formation and inhibition in DNA repair processes. In contrast, the radical-scavenging and antioxidant properties of silibinin and other flavonolignans in milk thistle extract may have contributed to the decrease in background tumors in rodents in the present studies. The fate of the active constituents of goldenseal and milk thistle is similar in humans and rodents; therefore, the modes of action may translate across species. Further studies are needed to extrapolate the findings to humans.

Targeting silibinin in the antiproliferative pathway

IMPORTANCE OF THE FIELD

Due to the failure and severe toxicity of cancer chemotherapy, silibinin, a natural flavonoid from the seeds of milk thistle, has recently received more attention for its potential anticancer and nontoxic roles in animals and humans. Silibinin has clearly demonstrated inhibition of multiple cancer cell signaling pathways, including growth inhibition, inhibition of angiogenesis, chemosensitization, and inhibition of invasion and metastasis. Cumulative evidence implicates that silibinin is a potential agent for cancer chemoprevention and chemotherapy.

AREAS COVERED IN THIS REVIEW

Our aim is to discuss the recent progress of silibinin in regulating multiple anticancer proliferative signaling pathways; the review covers literature mainly from the past 3 - 5 years.

WHAT THE READER WILL GAIN

One of the strategies for tumor therapy is eradication of cancer cells through targeting specific cell-proliferative pathways. This review highlights the current knowledge of silibinin in regulating multiple cellular proliferative pathways in cancer cells, including receptor tyrosine kinases, androgen receptor, STATs, NF-kappaB, cell cycle regulatory and apoptotic signaling pathways.

TAKE HOME MESSAGE

The molecular mechanisms of silibinin-mediated antiproliferative effects are mainly via receptor tyrosine kinases, androgen receptor, STATs, NF-kappaB, cell cycle regulatory and apoptotic signaling pathways in various cancer cells. Targeting inhibition of proliferative pathways through silibinin treatment may provide a new approach for improving chemopreventive and chemotherapeutic effects.

A randomized, controlled, double-blind, pilot study of milk thistle for the treatment of hepatotoxicity in childhood acute lymphoblastic leukemia (ALL)

BACKGROUND

Despite limited preclinical and clinical investigations, milk thistle (MT) is often used for the treatment of chemotherapy-associated hepatotoxicity. Limited treatment options exist for chemotherapy-related hepatoxicity. Given the wide use of MT, the authors investigated MT in both the laboratory and a clinical setting.

METHODS

In a double-blind study, children with acute lymphoblastic leukemia (ALL) and hepatic toxicity were randomized to MT or placebo orally for 28 days. Liver function tests were evaluated during the study period. To assess MT in vitro, the authors evaluated supratherapeutic concentrations in an ALL cell line.

RESULTS

Fifty children were enrolled. No significant differences in frequency of side effects, incidence and severity of toxicities, or infections were observed between groups. There were no significant changes in mean amino alanine transferase (ALT), aspartate amino transferase (AST), or total bilirubin (TB) at Day 28. At Day 56, the MT group had a significantly lower AST (P = .05) and a trend toward a significantly lower ALT (P = .07). Although not significantly different, chemotherapy doses were reduced in 61% of the MT group compared with 72% of the placebo group. In vitro experiments revealed no antagonistic interactions between MT and vincristine or L-asparaginase in CCRF-CEM cells. A modest synergistic effect with vincristine was observed.

CONCLUSIONS

In children with ALL and liver toxicity, MT was associated with a trend toward significant reductions in liver toxicity. MT did not antagonize the effects of chemotherapy agents used for the treatment of ALL. Future study is needed to determine the most effective dose and duration of MT and its effect on hepatotoxicity and leukemia-free survival.

Milk thistle extracts inhibit the oxidation of low-density lipoprotein (LDL) and subsequent scavenger receptor-dependent monocyte adhesion

Silymarin encompasses a group of flavonolignans that are extracted from Silybum marianum (Asteraceae) fruits. The silymarins have previously been reported to lower low-density lipoprotein (LDL) levels associated with high-fat diets. The present study reports the efficacy of the silymarins in inhibiting oxidized low-density lipoprotein (oxLDL) generation and subsequent scavenger receptor (SR) mediated monocyte adherence to oxLDL. The flavonolignans that comprise silymarin include silichristin (SC), silidianin (SD), silibinin (SBN), and isosilibinin (IS). These flavonolignans (300 microM) lowered oxLDL generation, measured by the thiobarbituric acid-reacting substances (TBARS) assay, by 60.0, 28.1, 60.0, and 30.1%, respectively. SBN treatment of LDL in the presence of copper sulfate (CuSO 4) resulted in a significant dose-dependent inhibition of monocyte adhesion. Inhibition was paralleled by a decrease in binding of anti-oxLDL antibodies recognized by U937 monocyte Fc gamma receptors (FcgammaR). These results showed that silymarin and SBN, likely through antioxidant and free radical scavenging mechanisms of action, inhibit the generation of oxLDL and oxidation-specific neoepitopes recognized by SR and FcgammaR expressed on monocytes/macrophages.

Multitargeted therapy of cancer by silymarin

Silymarin, a flavonolignan from milk thistle (Silybum marianum) plant, is used for the protection against various liver conditions in both clinical settings and experimental models. In this review, we summarize the recent investigations and mechanistic studies regarding possible molecular targets of silymarin for cancer prevention. Number of studies has established the cancer chemopreventive role of silymarin in both in vivo and in vitro models. Silymarin modulates imbalance between cell survival and apoptosis through interference with the expressions of cell cycle regulators and proteins involved in apoptosis. In addition, silymarin also showed anti-inflammatory as well as anti-metastatic activity. Further, the protective effects of silymarin and its major active constituent, silibinin, studied in various tissues, suggest a clinical application in cancer patients as an adjunct to established therapies, to prevent or reduce chemotherapy as well as radiotherapy-induced toxicity. This review focuses on the chemistry and analogues of silymarin, multiple possible molecular mechanisms, in vitro as well as in vivo anti-cancer activities, and studies on human clinical trials.

Advances in the use of milk thistle (Silybum marianum)

Milk thistle (Silybum marianum) is an herbal supplement used to treat liver and biliary disorders. Silymarin, a mixture of flavanoid complexes, is the active component that protects liver and kidney cells from toxic effects of drugs, including chemotherapy. Although milk thistle has not significantly altered the course of chronic liver disease, it has reduced liver enzyme levels and demonstrated anti-inflammatory and T cell-modulating effects. There is strong preclinical evidence for silymarin's hepatoprotective and anticarcinogenic effects, including inhibition of cancer cell growth in human prostate, skin, breast, and cervical cells. Milk thistle is considered safe and well-tolerated, with gastrointestinal upset, a mild laxative effect, and rare allergic reaction being the only adverse events reported when taken within the recommended dose range. More clinical trials of rigorous methodology, using standardized and well-defined products and dosages, are needed to evaluate the potential of silymarin against liver toxicity, chronic liver disease, and human cancers.