Determination of isoflavones in red clover and related species by high-performance liquid chromatography combined with ultraviolet and mass spectrometric detection

An Isoflavone Synthase Gene in Arachis hypogea Responds to Phoma arachidicola Infection Causing Web Blotch

Peanut web blotch is an important leaf disease caused by Phoma arachidicola, which seriously affects the quality and yield of peanuts. However, the molecular mechanisms of peanut resistance to peanut web blotch are not well understood. In this study, a transcriptome analysis of the interaction between peanut (Arachis hypogaea) and P. arachidicola revealed that total 2989 (779 up- and 2210 down-regulated) genes were all differentially expressed in peanut leaves infected by P. arachidicola at 7, 14, 21 days post inoculation. The pathways that were strongly differentially expressed were the flavone or isoflavone biosynthesis pathways. In addition, two 2-hydroxy isoflavanone synthase genes, IFS1 and IFS2, were strongly induced by P. arachidicola infection. Overexpression of the two genes enhanced resistance to Phytophthora parasitica in Nicotiana benthamiana. Knockout of AhIFS genes in peanut reduced disease resistance to P. arachidicola. These findings demonstrated that AhIFS genes play key roles in peanut resistance to P. arachidicola infection. Promoter analysis of the two AhIFS genes showed several defense-related cis-elements distributed in the promoter region. This study improves our understanding of the molecular mechanisms behind resistance of peanut infection by P. arachidicola, and provides important information that could be used to undertake greater detailed characterization of web blotch resistance genes in peanut.

Transformation profiles of the isoflavones in germinated soybean based on UPLC-DAD quantification and LC-QTOF-MS/MS confirmation

Germinated soybean is one kind of food and a medicine. In the actual process of producing a large amount of naturally germinated soybean, it is difficult to strictly control the germination process conditions. However, sprout length may be more suitable as the terminal judgment indicator for naturally germinated soybean. An UPLC-DAD method was developed and validated to explore the transformation profiles of soybean isoflavones in germinated yellow or black soybean with different sprout lengths. Moreover, an LC - QTOF-MS/MS method was used to avoid false positive results. The contents of daidzein, glycitein, and genistein almost reached their corresponding maximum values when the sprout length ranged from 1.0 cm to 1.5 cm (P < 0.05). Therefore, yellow soybean is suggested to be the processing raw material with higher contents of those isoflavones, and the optimal sprout length for germinated soybean may be in the range of 1.0-1.5 cm.

Estrogenic Isoflavones in Clover Plants, Flower Nectar, Unripe Honeys and Mature Honeys: A Natural Biochemical Transformation of Isoflavones by Honeybees

This study is the first to report on the presence of oestrogenic compounds in different clover flower nectar samples, in bee-deposited nectars collected from hive combs (unripe honey) and in mature honeys harvested from the same hives. The clover species investigated were two red clover (Trifolium pratense) cultivars, bred specifically for high isoflavone content, alongside a sainfoin (Onobrychis viciifolia) and a purple clover (T. purpureum) cultivar. A total of eight isoflavones, four of them non-glycosidic (biochanin A, formononetin, genistein and daidzein) the others glycosidic (sissotrin, ononin, genistin and daidzin), were targeted for identification and quantification in this study using high-performance thin-layer chromatography (HPTLC). Leaves and flower bracts of the clover samples were also investigated. Different isoflavone profiles were found across the four clover species and also in the different samples collected from each species indicating that, most likely due to the activity of honeybee (Apis mellifera) salivary enzymes, biochemical conversions take place when these bioactive compounds transition from flower nectar into ripe honey. Among the four investigated clover species, the two red clover cultivars, including their honeys, were found to contain higher levels of estrogenic compounds compared to other two cultivars.

An Insight on Synergistic Anti-cancer Efficacy of Biochanin A and Sulforaphane Combination Against Breast Cancer

Breast cancer is a serious malignancy that has higher rate of morbidity and mortality. It has been known to affect the women indifferently. The lack and side effects in the current therapeutic modules result in the search of the wide treatment options including combinatorial treatment. The goal of this study was to investigate combinatorial anti-proliferative efficacy of biochanin A (BCA) and sulforaphane (SFN) against MCF-7 breast cancer cells. The study involves the utilisation of various qualitative techniques including cytotoxicity analysis (MTT), morphogenic analysis, AO/EtBr, DAPI, ROS, cell cycle, and cell migration analysis in order to examine the combinatorial efficacy of BCA and SFN in inducing the cell death. The results had shown that the cytotoxicity of BCA and SFN was found to be around 24.5 µM and 27.2 µM respectively, while the combination of BCA and SFN had shown an inhibitory activity at about 20.1 µM. And furthermore, AO/EtBr and DAPI had shown a profound increase in apoptogenic activity of compounds when treated in combination at lower dose. This apoptogenic activity may be attributed to the increased ROS production. Moreover, it has been shown that the BCA and SFN have been involved in the down-regulation of ERK-1/2 signalling pathway resulting in induction of apoptosis of cancer cells. Thus, our results had concluded that BCA and SFN co-treatment could be used as an efficient therapeutic target against breast cancer. Furthermore, in vivo efficiency by which the co-treatment induces apoptosis has to be deliberated further in near future to make their use commercially.

Clover microgreen incorporation in diet-controlled diabetes and counteracted aflatoxicosis of rats

Diabetes mellitus is one of the chronic metabolic diseases whose control remains a challenge. Its increased incidence was mainly attributed to increased environmental contamination. Therefore, this study aims to investigate the effect of feeding clover microgreen (CM) on a diabetes model with or without aflatoxin exposure. Rats were distributed into 8 groups. G1 was a control group. G2 was fed CM. G3 was administered aflatoxin orally. G4 was fed clover and administered aflatoxin. G5 was diabetic rats. G6 was diabetic rats fed CM. G7 was diabetic rats administered aflatoxin. G8 was diabetic rats administered aflatoxin and fed CM. Phytochemical analysis of the CM showed that gardenin was the most common compound. The administration of aflatoxin aggravated diabetes. The groups fed CM showed a decreased glucose concentration compared to the unfed groups. Liver and kidney function parameters were improved by CM. The histopathological alteration of the pancreas, liver, and kidneys was relieved in CM-fed groups. The area % of insulin in islets of Langerhans was increased in CM-fed groups. Feeding CM also enhanced the oxidative stress biomarkers. In conclusion, CM improved all evaluated parameters in diabetic rats either exposed to aflatoxin or not compared to the control.

Isoflavone Metabolism by Lactic Acid Bacteria and Its Application in the Development of Fermented Soy Food with Beneficial Effects on Human Health

Isoflavones are phenolic compounds (considered as phytoestrogens) with estrogenic and antioxidant function, which are highly beneficial for human health, especially in the aged population. However, isoflavones in foods are not bioavailable and, therefore, have low biological activity. Additionally, their transformation into bioactive compounds by microorganisms is necessary to obtain bioavailable isoflavones with beneficial effects on human health. Many lactic acid bacteria (LAB) can transform the methylated and glycosylated forms of isoflavones naturally present in foods into more bioavailable aglycones, such as daidzein, genistein and glycitein. In addition, certain LAB strains are capable of transforming isoflavone aglycones into compounds with a greater biological activity, such as dihydrodaidzein (DHD), O-desmethylangolensin (O-DMA), dihydrogenistein (DHG) and 6-hydroxy-O-desmethylangolensin (6-OH-O-DMA). Moreover, Lactococcus garviae 20-92 is able to produce equol. Another strategy in the bioconversion of isoflavones is the heterologous expression of genes from Slackia isoflavoniconvertens DSM22006, which have allowed the production of DHD, DHG, equol and 5-hydroxy-equol in high concentrations by engineered LAB strains. Accordingly, the consequences of isoflavone metabolism by LAB and its application in the development of foods enriched in bioactive isoflavones, as well as health benefits attributed to their consumption, will be addressed in this work.

Investigation of apoptotic and antiproliferative effects of Turkish natural tetraploids Trifolium pratense L. extract on C6 glioblastoma cells via light and electron microscopy

Glioblastoma (GBM) is the most common type of primary brain tumors in adults, characterized by its ability to proliferate rapidly and its tendency to aggressively and strongly invaded the surrounding brain tissue. The standard treatment approach of GBM is surgical resection followed by simultaneous chemotherapy and radiation. However, a significant number of GBM cases develop resistance to currently used chemotherapeutic drugs. Therefore, there is a need for the development of new chemotherapeutic agents. Trifoliumpratense L. is an endemic plant containing various isoflavones such as biochanin A, genistein, daidzein, and formononetin in high concentrations, and it has been shown in various studies that these molecules can function as anticancer agents. The present study was designed to determine the effect of the possible anticarcinogenic effects of the Trifolium pratense L. which grown in our country and to obtain new treatment approaches alternative to the classical treatment protocols applied in the treatment of GBM. C6 glioblastoma cells were cultured with Trifolium pratense L. Cell proliferation, apoptotic cell morphology, and cell structure were evaluated with CCK8, Annexin V, cytochrome c, CD117, and Betatubulin labeling, respectively. And also, investigated effects of this Turkish tetraploid on GBM by TEM. Decreased cell proliferation and increased number of apoptotic cells were observed depending on the increasing doses of Trifolium pratense L. In addition, intense morphological changes were detected depending on increasing doses. In this context, we believe that the plant Trifolium pratense L., may be a new alternative and adjuvant agent for the treatment of GBM.

The Potential Therapeutic Properties of Prunetin against Human Health Complications: A Review of Medicinal Importance and Pharmacological Activities

BACKGROUND

Flavonoids are polyphenolic compounds found to be present in nature and abundant in flowers and fruits. Flavonoidal class phytochemicals have gained interest in the scientific field because of their important pharmacological activities. Several scientific studies have revealed anti-bacterial, anti-oxidant, anti-fungal, analgesic, anti-viral, anti-inflammatory, anti-tumor, anti-parasitic and anti-allergic activities of flavonoidal class phytochemicals. Prunetin is an O-methylated isoflavone that belongs to the phytochemical phytoestrogen class, found to be present in licorice, red cherry, soybean and legumes.

METHODS

Biological potential and pharmacological activities of prunetin have been investigated in the present work through scientific data analysis of numerous scientific research works. Numerous literature databases have been searched in order to collect the scientific information on prunetin in the present work. Pharmacological activities of prunetin have been investigated in the present work through literature data analysis of different scientific research works. Scientific data have been collected from Google Scholar, Google, PubMed, Science Direct and Scopus. Analytical data on prunetin has been collected from literature sources and analyzed in the present work.

RESULTS

Scientific data analysis revealed the biological importance of prunetin in medicine. Prunetin was found to be present in the pea, peach, Oregon cherry, skimmed cheese, cheese, cow kefir and goat kefir. Prunetin is also present in the Prunus avium, Andira surinamensis, Butea superba, Dalbergia sympathetica, Ficus nervosa, Pterospartum tridentatum and Pycnanthus angolensis. Pharmacological data analysis revealed the biological importance of prunetin on bone disorders, cancers, especially hepatocellular carcinoma, urinary bladder cancer, gastric cancer, ovarian cancer, human airway, gut health and enzymes. Scientific data analysis revealed biological effectiveness of prunetin for their angiogenic effects, anti-inflammatory, anti-oxidant, antimicrobial, estrogenic and vasorelaxant potential. Analytical data revealed the importance of modern analytical techniques for qualitative and quantitative analysis of prunetin in the scientific fields.

CONCLUSION

Scientific data analysis in the present investigation revealed the biological importance and pharmacological activities of prunetin in medicine.

A Review of the Phytochemistry and Bioactivity of Clover Honeys (Trifolium spp.)

This review covers a comprehensive overview of the phytoconstituents and bioactivities reported to date for clover honeys produced from various Trifolium spp. against the backdrop of a more general discussion of the chemistry and bioactivity of these important agricultural species. While research into the phytochemical composition of various honeys and their associated bioactivities is growing, this review demonstrates that the literature to date has seen only a limited number of studies on clover honeys. Surprisingly, there appear to be no comparative data on the concentration of flavonoids in general or isoflavonoids specifically in different clover honeys, although the latter have been identified as a main group of bioactive compounds in red clover plants. Based on the findings of this review, the presence of phytoestrogenic isoflavonoids (e.g., formononetin, biochanin A, genistein, daidzein, glycitein) in clover plants and, by extension, in clover honeys should be further investigated, specifically of clover species outside the three popular perennial clovers (red, white and alsike clovers) to exploit new opportunities of potential benefit to both the pharmaceutical and apiculture industries.

Neuroprotective mechanisms of red clover and soy isoflavones in Parkinson's disease models

Parkinson's disease (PD) is a neurodegenerative disorder characterized by nigrostriatal degeneration and the spreading of aggregated forms of the presynaptic protein α-synuclein (aSyn) throughout the brain. PD patients are currently only treated with symptomatic therapies, and strategies to slow or stop the progressive neurodegeneration underlying the disease's motor and cognitive symptoms are greatly needed. The time between the first neurobiochemical alterations and the initial presentation of symptoms is thought to span several years, and early neuroprotective dietary interventions could delay the disease onset or slow PD progression. In this study, we characterized the neuroprotective effects of isoflavones, a class of dietary polyphenols found in soy products and in the medicinal plant red clover (Trifolium pratense). We found that isoflavone-rich extracts and individual isoflavones rescued the loss of dopaminergic neurons and the shortening of neurites in primary mesencephalic cultures exposed to two PD-related insults, the environmental toxin rotenone and an adenovirus encoding the A53T aSyn mutant. The extracts and individual isoflavones also activated the Nrf2-mediated antioxidant response in astrocytes via a mechanism involving inhibition of the ubiquitin-proteasome system, and they alleviated deficits in mitochondrial respiration. Furthermore, an isoflavone-enriched soy extract reduced motor dysfunction exhibited by rats lesioned with the PD-related neurotoxin 6-OHDA. These findings suggest that plant-derived isoflavones could serve as dietary supplements to delay PD onset in at-risk individuals and mitigate neurodegeneration in the brains of patients.

Study of the Interactions between MeOH and Daidzein at the Molecular Level

In this study, the interactions between daidzein and methanol were studied to investigate isoflavone extraction. The complexes of MeOH-daidzein = 1:1, 2:1, 4:1, and 7:1 were studied using DFT/B3LYP-D3. According to the findings of this study, daidzein can act as a hydrogen bond donor as well as an acceptor. Binding energies demonstrate that more MeOH molecules interacting with daidzein could give more stability to the system. The strengths of the hydrogen bonds reveal that daidzein prefers to act as a hydrogen bond donor than an acceptor. The atoms in molecules (AIM) topological analysis was performed to analyze the nature of the hydrogen bonds. Moreover, daidzein, genistein, and glycitein are the most common soybean isoflavones, and their properties during extraction were also studied. The binding energies show that the soy isoflavone genistein is more reactive with the solvent than daidzein, followed by glycitein. The extraction conditions of the three common soy isoflavones in MeOH solution were obtained at 321, 328, and 348 K for genistein, daidzein, and glycitein, respectively. The generalized Kohn-Sham energy decomposition analysis (GKS-EDA) results indicate that the solute-solvent molecular interactions are typical hydrogen bonds with predominantly electrostatic and exchange energies in nature.

Quantitative analysis of nine isoflavones in traditional Chinese medicines using mixed micellar liquid chromatography containing sodium dodecylsulfate/β-cyclodextrin supramolecular amphiphiles

Isoflavone is one of the phytoestrogens that have estrogenic effects, so it is usually served as an active ingredient for quality control of traditional Chinese medicines rich in isoflavones. Nine isoflavones commonly found in traditional Chinese medicines were separated in 30 min using mixed micellar liquid chromatography. The mobile phase consisted of 0.08 M sodium dodecylsulfate and 6.05 mM β-cyclodextrin:methanol (87:13, v/v) at pH 3 and eluted isocratically at 1 mL/min through a C18 column. In this study, we systematically optimized the chromatographic conditions including the pH, the composition and concentration of surfactants, the type and ratio of organic solvents, and column temperature. The method was validated according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use guidelines. There is no report using micellar liquid chromatography to detect isoflavones, and the optimized method has been successfully applied to quantify isoflavones in red clover and Radix Puerariae. This method is efficient, cheap, and convenient. Finally, we verified the existence of supramolecular amphiphilic vesicles in the mobile phase by transmission electron microscopy to explain the increased chromatographic efficiency.

Single-Laboratory Validation of UHPLC-MS/MS Assays for Red Clover Isoflavones in Human Serum and Dietary Supplements

BACKGROUND

Extracts of red clover (Trifolium pratense L.) containing estrogenic and pro-estrogenic isoflavones are used in dietary supplements primarily for the management of menopausal symptoms in women.

OBJECTIVE

A UHPLC-MS/MS assay was developed and validated for the quantitative analysis of the six major red clover isoflavones in dietary supplements and in human serum in support of clinical trials.

METHODS

Enzymatic deconjugation of isoflavone glucuronides and sulfate conjugates in human serum specimens was carried out followed by protein precipitation. Isoflavones in red clover dietary supplements were acid hydrolyzed to release aglycons from glycosides. UHPLC separations (< 4 min) were combined with MS/MS using collision-induced dissociation, selective reaction monitoring and deuterated internal standards to measure biochanin A, formononetin, daidzein, genistein, irilone, and prunetin.

RESULTS

The method was validated with respect to selectivity, specificity, accuracy, linearity, precision, LOD, and LOQ. The calibration curves for all analytes were linear (R2 > 0.998). The mean recovery for low-, medium- and high-quality control standards ranged between 80% and 108%. The precision of the method was assessed using coefficients of variation, which were <15%.

CONCLUSIONS

The UHPLC-MS/MS method is fast, precise, sensitive, selective, accurate, and applicable to the quantitative analysis of red clover isoflavones in different matrices.

HIGHLIGHTS

This validated UHPLC-MS/MS assay is applicable to the rapid quantitative analysis of red clover isoflavones in human serum and in dietary supplements.

Red Clover (Trifolium pratense L.) Sprout Prevents Metabolic Syndrome

We examined the prevention effect of red clover (Trifolium pratense L.) sprout on metabolic syndrome using a high-carbohydrate and high-fat diet (Western diet; WD)-induced male C57BL/6J obese model mouse. Red clover sprout-lyophilized powder (RC) contained 3.5 mg/g dry-weight of formononetin as a major phenolic compound, as analyzed by high performance liquid chromatography. Supplementation of 0.3% (w/w) RC in a WD (WD+RC) showed an anti-obesity effect and ameliorated lipid metabolism in the obese model mice. Additionally, fasting plasma glucose levels were significantly reduced in the WD+RC group. Administration of 0.1 mg/kg formononetin reduced the postprandial blood glucose level, as assessed using the oral maltose tolerance test. However, no significant formononetin intake effect was observed on the plasma insulin level. These results suggest that the formononetin contained in red clover sprout inhibits α-glucosidase and thereby contributes to reducing the postprandial blood glucose response in mice.

Integrated Phytochemical Analysis Based on UPLC-MS and Network Pharmacology Approaches to Explore the Quality Control Markers for the Quality Assessment of Trifolium pratense L

Red clover consists of the overground parts and inflorescence of Trifolium pratense L., a leguminous plant belonging to the genus Trifolium. It is widely distributed worldwide and has long been used in traditional medicine. In this study, a combination approach using UPLC-MS and network pharmacology was applied to explore the quality control markers for the quality assessments of red clover. Firstly, UPLC-MS was used to identify the compounds in different parts of red clover. Twenty-eight compounds were totally identified. According to the traditional clinical efficacy of red clover, a compound-target-function network was constructed by network pharmacology to discover the main active compounds based on the identified compounds. Nine compounds of chlorogenic acid, daidzin, calycosin-7-O-β-d-glucoside, genistin, ononin, daidzein, genistein, formononetin, and biochanin A were filtrated and further confirmed in rat plasma in view of the blood-absorbed components taking effects. Finally, a novel method for simultaneously detecting the nine quality control markers was developed by UPLC-QQQ-MS in an effort to assess the quality of red clover. For all samples, the average contents of the nine compounds measured from high to low consist of formononetin, ononin, biochanin A, genistin, daidzin, calycosin-7-O-β-d-glucoside, genistein, daidzein, and chlorogenic acid. The samples from Gansu province showed the best quality in the three producing areas This study provides new strategies to explore the quality control markers and develops a novel method for the quality assessment of red clover.

Phytochemical profile and pharmacological properties of Trifolium repens

Trifolium repens belongs to the family Leguminosae and has been used for therapeutic purposes as traditional medicine. The plant is widely used as fodder and leafy vegetables for human uses. However, there is a lack of a detailed review of its phytochemical profile and pharmacological properties. This review presents a comprehensive overview of the phytochemical profile and biological properties of T. repens. The plant is used as antioxidants and cholinesterase inhibitors and for anti-inflammatory, antiseptic, analgesic, antirheumatic ache, and antimicrobial purposes. This review has summarized the available updated useful information about the different bioactive compounds such as simple phenols, phenolic acids, flavones, flavonols, isoflavones, pterocarpans, cyanogenic glucosides, saponins, and condensed tannins present in T. repens. The pharmacological roles of these secondary metabolites present in T. repens have been presented. It has been revealed that T. repens contain important phytochemicals, which is the potential source of health-beneficial bioactive components for food and nutraceuticals industries.

Metabolic Profiling Provides Unique Insights to Accumulation and Biosynthesis of Key Secondary Metabolites in Annual Pasture Legumes of Mediterranean Origin

Annual legumes from the Mediterranean region are receiving attention in Australia as alternatives to traditional pasture species. The current study employed novel metabolic profiling approaches to quantify key secondary metabolites including phytoestrogens to better understand their biosynthetic regulation in a range of field-grown annual pasture legumes. In addition, total polyphenol and proanthocyanidins were quantified using Folin-Ciocalteu and vanillin assays, respectively. Metabolic profiling coupled with biochemical assay results demonstrated marked differences in the abundance of coumestans, flavonoids, polyphenols, and proanthocyanidins in annual pasture legume species. Genetically related pasture legumes segregated similarly from a chemotaxonomic perspective. A strong and positive association was observed between the concentration of phytoestrogens and upregulation of the flavonoid biosynthetic pathway in annual pasture legumes. Our findings suggest that evolutionary differences in metabolic dynamics and biosynthetic regulation of secondary metabolites have logically occurred over time in various species of annual pasture legumes resulting in enhanced plant defense.

Soy Isoflavones Inhibit Endothelial Cell Dysfunction and Prevent Cardiovascular Disease

Soybeans are among the most popular foods worldwide, and intake of soy-containing foods has been associated with many health benefits in part because of it structure similar to estrogen. Epidemiologic studies have demonstrated that soy consumption improves serum profiles of hypercholesterolemic patients. Several studies have also indicated an inverse relationship between the consumption of soy isoflavones and the incidence of cardiovascular diseases (CVD). Soy is a rich dietary source of isoflavones. The main soy isoflavones are daidzein and genistein; equol, another isoflavone and a major intestinal bacterial metabolite of daidzein, is generated by enterobacterial effects. Many isoflavones have antioxidative effects and anti-inflammatory actions, as well as induce nitric oxide production to maintain a healthy endothelium and prevent endothelial cell dysfunction. These effects may limit the development of atherosclerosis and CVD and restore healthy endothelial function in altered endothelia. Although the evidence supporting the benefits of soy isoflavones in CVD prevention continues to increase, the association between soy isoflavones and disease is not fully understood. This review summarized recent progress in identifying the preventive mechanisms of action of dietary soybean isoflavones on vascular endothelial cells. Furthermore, it describes the beneficial roles that these isoflavones may have on endothelial dysfunction-related atherosclerosis.

Age-related pharmacodynamics in a bumblebee-microsporidian system mirror similar patterns in vertebrates

Immune systems provide a key defence against diseases. However, they are not a panacea and so both vertebrates and invertebrates co-opt naturally occurring bioactive compounds to treat themselves against parasites and pathogens. In vertebrates, this co-option is complex, with pharmacodynamics leading to differential effects of treatment at different life stages, which may reflect age-linked differences in the immune system. However, our understanding of pharmacodynamics in invertebrates is almost non-existent. Critically, this knowledge may elucidate broad parallels across animals in regard to the requirement for the co-option of bioactive compounds to ameliorate disease. Here, we used biochanin A, an isoflavone found in the pollen of red clover (Trifolium pratense), to therapeutically treat Nosema bombi (Microsporidia) infection in bumblebee (Bombus terrestris) larvae and adults, and thus examine age-linked pharmacodynamics in an invertebrate. Therapeutic treatment of larvae with biochanin A did not reduce the infection intensity of N. bombi in adults. In contrast, therapeutic treatment of adults did reduce the infection intensity of N. bombi This transition in parasite resistance to bioactive compounds mirrors the age-linked pharmacodynamics of vertebrates. Understanding how different life-history stages respond to therapeutic compounds will provide novel insights into the evolution of foraging and self-medication behaviour in natural systems more broadly.

Trifolium pratense (Red Clover) Improve SIRT1 Expression and Glycogen Content in High Fat Diet-Streptozotocin Induced Type 2 Diabetes in Rats

Flowering tops of Trifolium pratense L. (Fabaceae) are known for its traditional medicinal values. In present study, our aim was to investigate effect of standardized aqueous extract of flowering tops of Trifolium pratense L. on insulin resistance and SIRT1 expression in type 2 diabetic rats. Type 2 diabetes was induced by feeding high fat diet and administering low dose of streptozotocin. Diabetic animals were treated with standardized aqueous extract at three different doses. Parameters such as blood glucose, lipid profile, glycohemoglobin, insulin sensitivity, HOMA-IR and liver glycogen content were measured. Changes in morphology and expression of SIRT1 in pancreatic tissue were measured in histopathological and immunohistological studies. Aqueous extract treatment showed reduction in hyperglycemia and improved insulin sensitivity. Extract treatment also showed reduction in formation of glycated hemoglobin and improved liver glycogen level. Histopathological study revealed protecting effect of extract in pancreatic tissue against hyperglycemia induced damage. Treatment increased expression of SIRT1 in rat pancreatic tissue. Results indicate that the aqueous extract of Trifolium pratense had beneficial role in improving insulin sensitivity and SIRT1 expression.

Molecular Understanding of Solvents and Glycitein Interaction during Extraction

Hydrogen bonding interaction plays a crucial role in liquid systems. Methanol, ethanol, and acetone are the most commonly used solvents to extract isoflavones from soybeans. The structural and electronic properties of the molecular clusters of naturally occurring glycitein with solvents were investigated using the density functional theory method employing the B3LYP-D3/cc-pVTZ approach. The influence of the solvent was carried out by using the polarized continuum model (PCM). The geometry optimization, vibrational frequencies, and topological parameters have been assessed at the same level of theory. From the molecular structure and thermodynamic point of view, the most stable structures are formed by the interaction between the carbonyl group of glycitein and MeOH or EtOH. For acetone-glycitein, the strongest interaction is formed by the interaction of the hydroxyl group of glycitein with the carbonyl group of acetone. All the hydrogen bonds in the MeOH/EtOH/acetone-glycitein complexes are closed-shell interactions. This study can help increase the efficiency of extraction.

Preparation of DESIGNER extracts of red clover (Trifolium pratense L.) by centrifugal partition chromatography

Starting with an isoflavone-rich red clover extract (RCE), this study expands on the DESIGNER approach to Deplete and Enrich Select Ingredients to Generate Normalized Extract Resources using countercurrent separation (CCS) methodology. A hydrostatic CCS (also known as centrifugal partition chromatography, CPC) technique was used to enrich and deplete selected bioactive isoflavones of RCE extracts. In order to efficiently prepare large enough DESIGNER extracts from RCE for biological testing including in vivo assays, it was necessary to choose a balance between resolution and a loading capacity of at least 1 g per separation for the selected solvent system (SS). Adding 3 mL of DMSO to the sample containing equal amounts of upper and lower phases of hexanes-ethyl acetate-methanol-water (HEMWat 5.5/4.5/5/5, v/v) allowed 1 g of RCE to be dissolved in the sample without disrupting the chromatographic resolution of the target isoflavones. CPC experiments using other solubility modifiers, acetone and acetonitrile indicated that these modifiers increase solubility significantly, even better than DMSO, but the separation of target compounds was sufficiently disturbed to be unacceptable for producing the desired DESIGNER extracts. The preparation of DESIGNER extracts was achieved with two sequential CPC separations. The first produced a biochanin A enriched fraction (93.60% w/w) with only small amounts of other isoflavones: 2.30% w/w prunetin, 1.17% w/w formononetin, and 0.12% w/w irilone. Gravimetric investigations of this step demonstrated the high efficiency of CCS technology for full and unbiased sample recovery, confirmed experimentally to be 99.80%. A formononetin enriched fraction from this first separation was re-chromatographed on a more polar HEMWat (4/6/4/6, v/v) SS to produce a formononetin enriched DESIGNER fraction of 94.70% w/w purity. The presence of the minor (iso)flavonoids: 3.16% w/w pseudobaptigenin, 0.39% w/w kaempferol, and 0.31% w/w genistein was also monitored in these fractions. Chromatographic fractions, combined fractions, and DESIGNER extracts were analyzed with quantitative ¹H NMR (qHNMR) spectroscopy which provided purity information, quantitation, and structural identification of the components.

Cell Cycle Arrest in Different Cancer Cell Lines (Liver, Breast, and Colon) Induces Apoptosis under the Influence of the Chemical Content of Aeluropus lagopoides Leaf Extracts

Natural products, especially secondary metabolites produced by plants under stressed conditions, are shown to have different pharmacological impacts from one to another. Aeluropus lagopoides is one of the common halophyte plants that survive under stressed conditions, and has been used for healing wounds and as a painkiller. The bioactivity and the chemical composition of this plant have been poorly investigated. Consequently, the chemical components of A. lagopoides leaves were extracted using hexane (nonpolar), ethyl acetate (semi-polar), and n-butanol (polar) to extract the most extensive variety of metabolites. The cytotoxicity and anticancer impact of extracted secondary metabolites were evaluated against breast (MCF-7), colon (HCT-116), and liver (HepG2) cancer cell lines using a SulphoRhodamine-B (SRB) test. Their mechanisms of action were verified by observing the appearance of apoptotic bodies using the fluorescent microscope, while their antiproliferative impacts were evaluated using a flow cytometer. Results revealed that secondary metabolites extracted using hexane and ethyl acetate had the highest cytotoxicity and thus the greatest anticancer activity effect on HepG2 with IC50 (24.29 ± 0.85 and 11.22 ± 0.679 µg/mL, respectively). On the other hand, flow cytometer results showed that secondary metabolites could inhibit the cell cycle in the G0/G1 phase. To ascertain the chemical composition⁻function relationship, the extracts were analyzed using LC-MS/MS. Accordingly, A. lagopoides hexane and ethyl acetate extracts may contain agents with anticancer potential.

Identification of Polyphenols, Glycoalkaloids, and Saponins in Solanum scabrum Berries Using HPLC-UV/Vis-MS

Consumption safety of Solanum scabrum berries is controversial in different cultural practices and evaluation of the toxicity as well as micronutrition value relies on relevant phytochemical study. Thus, this study aimed to systematically profile the phytochemicals in the berries from different genetic sources and maturity. Using a combination of three different and complementary methods of HPLC-UV/Vis-MS or MS/MS with acid-assisted hydrolysis, a total of 54 phytochemicals were identified including polyphenols, saponins and toxic glycoalkaloids. Particularly, a broad range of glycoalkaloids of solasodine and its uncommon or potentially novel hydroxylated and methylated derivatives were reported, with the structure putatively identified based on the known scaffold-fragmentation pattern. Other identified phytochemicals included phenolic acids of chlorogenic acid and neochlorogenic acid, flavonol glycosides of quercetin and isorhamnetin, anthocyanins of petunidin, malvidin and delphinidin, and saponins of diosgenin and tigogenin. PRACTICAL APPLICATION: This study provides solutions for identifying the phytochemicals of S. scabrum berries, and unveiled for the first time a wide range of toxic glycoalkaloids of solasodine and analogues in the berries from different genetic sources and maturation stages. This work laid the foundation for prospective quantitative determination of berry phytochemicals and future toxicity and nutrition evaluation, and could also apply to facilitate screening or breeding for glycoalkaloid-deficient genotypes that can be used as new food supply.

UPLC-Q-TOF-MS and UPLC-MS/MS methods for metabolism profiles and pharmacokinetics of major compounds in Xuanmai Ganjie Granules

Xuanmai Ganjie Granules (XMGJ), a widely used Chinese herbal formula in the clinic, is used for treatment of sore throats and coughs. Despite the chemical constituents having been clarifying by our previous studies, both of the metabolism and pharmacokinetic studies of XMGJ are unclear. This study aimed to explore the disposition process of XMGJ in vivo. A sensitive and selective ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) method was developed to analyze the absorbed components and metabolites in rat plasma and urine after oral administration of XMGJ. A total of 42 absorbed components, including 16 prototype compounds and 26 metabolites, were identified or tentatively characterized in rat plasma and urine after oral administration of XMGJ. Moreover, the pharmacokinetic studies of five compounds of XMGJ were investigated using ultra-high liquid chromatography with tandem mass spectrometry method. The results indicated that liquiritin, harpagoside, glycyrrhetic acid, liquiritigenin, formononetin and their metabolites might be the major components involved in the pharmacokinetic and metabolism process of XMGJ. This research showed a comprehensive investigation of XMGJ in vivo, which could provide a meaningful basis for further material basis and pharmacological as well as toxicological research.

Molecular interaction between MeOH and genistein during soy extraction

Genistein has received great attention due to its possible anti-oxidant properties. The interaction between genistein and the extraction solvent helps in understanding the extraction efficiency. Hydrogen bonding plays a crucial role in liquid systems. Density functional theory quantum chemical computations in both gas phase and solution were performed to investigate the molecular interaction between genistein and methanol. All the resulting complexes (MeOH : genistein = 1 : 1, 2 : 1, 3 : 1, 6 : 1) were studied using the B3LYP-D3 computational level and the cc-pVTZ basis set. Binding energies demonstrate that more MeOH molecules surrounding genistein could stabilize the system more. Geometry optimizations show that there are strong O–H⋯O interactions between MeOH and genistein. The electron density and the corresponding Laplacian of charge density at bond critical points were also calculated using AIM theory, and the results are in line with the structural and energetic analysis of the studied system. Moreover, energy decomposition analysis shows that the exchange energy term has the largest contribution to the attraction interaction energy as compared with other energy terms. Meanwhile, this study shows that the MeOH–genistein system is more stable under basic conditions. This study could help increase the efficiency of extraction.

The interaction between genistein and extraction solvent helps in understanding the extraction efficiency.

Effects of isoflavones on breast tissue and the thyroid hormone system in humans: a comprehensive safety evaluation

Isoflavones are secondary plant constituents of certain foods and feeds such as soy, linseeds, and red clover. Furthermore, isoflavone-containing preparations are marketed as food supplements and so-called dietary food for special medical purposes to alleviate health complaints of peri- and postmenopausal women. Based on the bioactivity of isoflavones, especially their hormonal properties, there is an ongoing discussion regarding their potential adverse effects on human health. This review evaluates and summarises the evidence from interventional and observational studies addressing potential unintended effects of isoflavones on the female breast in healthy women as well as in breast cancer patients and on the thyroid hormone system. In addition, evidence from animal and in vitro studies considered relevant in this context was taken into account along with their strengths and limitations. Key factors influencing the biological effects of isoflavones, e.g., bioavailability, plasma and tissue concentrations, metabolism, temporality (pre- vs. postmenopausal women), and duration of isoflavone exposure, were also addressed. Final conclusions on the safety of isoflavones are guided by the aim of precautionary consumer protection.

Recent (2000-2015) developments in the analysis of minor unknown natural products based on characteristic fragment information using LC-MS

Liquid chromatography-Mass Spectrometry (LC-MS) has been widely used in natural product analysis. Global detection and identification of nontargeted components are desirable in natural product research, for example, in quality control of Chinese herbal medicine. Nontargeted components analysis continues to expand to exciting life science application domains such as metabonomics. With this background, the present review summarizes recent developments in the analysis of minor unknown natural products using LC-MS and mainly focuses on the determination of the molecular formulae, selection of precursor ions, and characteristic fragmentation patterns of the known compounds. This review consists of three parts. Firstly, the methods used to determine unique molecular formula of unknown compounds such as accurate mass measurements, MSⁿ spectra, or relative isotopic abundance information, are introduced. Secondly, the methods improving signal-to-noise ratio of MS/MS spectra by manual-MS/MS or workflow targeting-only signals were elucidated; pure precursor ions can be selected by changing the precursor ion isolated window. Lastly, characteristic fragmentation patterns such as Retro-Diels-Alder (RDA), McLafferty rearrangements, "internal residue loss," and so on, occurring in the molecular ions of natural products are summarized. Classical application of characteristic fragmentation patterns in identifying unknown compounds in extracts and relevant fragmentation mechanisms are presented (RDA reactions occurring readily in the molecular ions of flavanones or isoflavanones, McLafferty-type fragmentation reactions of some natural products such as epipolythiodioxopiperazines; fragmentation by "internal residue loss" possibly involving ion-neutral complex intermediates). © 2016 Wiley Periodicals, Inc. Mass Spec Rev 37:202-216, 2018.

Application of ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry in identification of three isoflavone glycosides and their corresponding metabolites

RATIONALE

Metabolites of isoflavones have attracted much attention in recent years due to their potential bioactivities. However, the complex constituents of the metabolic system and the low level of metabolites make them difficult to analyze. A mass spectrometry (MS) method was applied in our identification of metabolites and study of their fragmentation pathways due to the advantages of rapidity, sensitivity, and low level of sample consumption.

METHODS

Three isoflavone glycosides and their metabolites were identified using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/QTOF-MS). These metabolites were obtained by anaerobically incubating three isoflavone glycosides with human intestinal flora. The characteristic fragments of isoflavone glycosides and their metabolites were used for the identification work.

RESULTS

Two metabolites from ononin, three metabolites from irilone-4'-O-β-D-glucoside, and five metabolites from sissotrin were identified respectively by the retention time (RT), accurate mass, and mass spectral fragmentation patterns. The losses of the glucosyl group, CO from the [M+H]⁺ ion were observed for all the three isoflavone glycosides. The characteristic retro-Diels-Alder (RDA) fragmentation patterns were used to differentiate the compounds. The metabolic pathways of the three isoflavone glycosides were proposed according to the identified chemical structures of the metabolites.

CONCLUSIONS

A selective, sensitive and rapid method was established for detecting and identifying three isoflavone glycosides and their metabolites using UPLC/QTOF-MS. The established method can be used for further rapid structural identification studies of metabolites and natural products. Furthermore, the proposed metabolic pathways will be helpful for understanding the in vivo metabolic process of isoflavone.

Protective effect of flavonoids from Cyclocarya paliurus leaves against carbon tetrachloride-induced acute liver injury in mice

Cyclocarya paliurus (Batal.) Iljinskaja (C. paliurus), known locally as 'sweet tea tree', is commonly cultivated in China. Flavonoids from Cyclocarya paliurus (Batal.) Iljinskaja (FC) is reported to exhibit multiple biological effects, including anti-inflammatory, anti-oxidant and anti-diabetic activities. However, their influence on carbon tetrachloride (CCl₄)-induced acute liver injury remains unclear. This study was designed to investigate the hepatoprotective effect of total flavonoids from C. paliurus leaves. Results revealed that flavonoids from C. paliurus significantly decreased CCl₄-induced elevation of activities of aspartate transaminase (AST), alanine transaminase (ALT) and superoxide dismutase (SOD) as well as the level of malondialdehyde (MDA), and markedly increased the levels of SOD, total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) compared with the model group. Structures of mainly compounds were elucidated by nuclear magnetic resonance (NMR), mass spectrometry (MS) spectroscopic and chemical analyses. This study clearly shows that flavonoids from C. paliurus exert a potent protective effect against CCl₄-induced acute liver injury in mice. Its hepatoprotective effect appears to be closely associated with its antioxidant activity. The results indicated that flavonoids from C. paliurus leaves could be considered as a potent food supplement in the prevention of acute liver injury.

Inducible De Novo Biosynthesis of Isoflavonoids in Soybean Leaves by Spodoptera litura Derived Elicitors: Tracer Techniques Aided by High Resolution LCMS

Isoflavonoids are a characteristic family of natural products in legumes known to mediate a range of plant-biotic interactions. For example, in soybean (Glycine max: Fabaceae) multiple isoflavones are induced and accumulate in leaves following attack by Spodoptera litura (Lepidoptera: Noctuidae) larvae. To quantitatively examine patterns of activated de novo biosynthesis, soybean (Var. Enrei) leaves were treated with a combination of plant defense elicitors present in S. litura gut content extracts and L-α-[13C9, 15N]phenylalanine as a traceable isoflavonoid precursor. Combined treatments promoted significant increases in 13C-labeled isoflavone aglycones (daidzein, formononetin, and genistein), 13C-labeled isoflavone 7-O-glucosides (daidzin, ononin, and genistin), and 13C-labeled isoflavone 7-O-(6″-O-malonyl-β-glucosides) (malonyldaidzin, malonylononin, and malonylgenistin). In contrast levels of 13C-labeled flavones and flavonol (4',7-dihydroxyflavone, kaempferol, and apigenin) were not significantly altered. Curiously, application of fatty acid-amino acid conjugate (FAC) elicitors present in S. litura gut contents, namely N-linolenoyl-L-glutamine and N-linoleoyl-L-glutamine, both promoted the induced accumulation of isoflavone 7-O-glucosides and isoflavone 7-O-(6″-O-malonyl-β-glucosides), but not isoflavone aglycones in the leaves. These results demonstrate that at least two separate reactions are involved in elicitor-induced soybean leaf responses to the S. litura gut contents: one is the de novo biosynthesis of isoflavone conjugates induced by FACs, and the other is the hydrolysis of the isoflavone conjugates to yield isoflavone aglycones. Gut content extracts alone displayed no hydrolytic activity. The quantitative analysis of isoflavone de novo biosynthesis, with respect to both aglycones and conjugates, affords a useful bioassay system for the discovery of additional plant defense elicitor(s) in S. litura gut contents that specifically promote hydrolysis of isoflavone conjugates.

Isoflavone Content in Subterranean Clover Germplasm from Sardinia

Subterranean clover (Trifolium subterraneum) is an important pasture legume, and Sardinia is known as a major centre of diversification of this species. As other legumes, this clover produces biologically active flavonoids including the subclass of isoflavones that are natural phytoestrogens with positive health effects. Present sources of isoflavones for medical/nutraceutical treatments are red clover (Trifolium pratense) and soybean (Glycine max). This study assessed the content and composition of flavonoids in 14 subterranean clover genotypes from Sardinia, grown ex-situ in comparison with two red clover ecotypes, to acquire information on the potential of the species as an alternative source of isoflavones for possible exploitation. Twenty compounds were tentatively identified across the two clovers after HPLC and LC/ESI-MS analyses, including clovamide, four flavonols, and 15 isoflavones. Most compounds were present as glucosides or glucosyl malonates. Subterranean clover extracts mainly comprised of derivatives of the isoflavones genistein, biochanin A, and formononetin. Compared to red clover, subterranean clover had higher content of total isoflavones and lower concentration of total flavonols. The isoflavone concentration in subterranean clover was higher than literature data for soybean or red clover. The existing genotypic variation warrants the possibility of selecting varieties with high isoflavone concentration for nutraceutical or pharmaceutical purposes.

Determination of Phytoestrogen Content in Fresh-Cut Legume Forage

The aim of the study was to determine phytoestrogen content in fresh-cut legume forage. This issue has been much discussed in recent years in connection with the health and safety of feedstuffs and thus livestock health. The experiments were carried out on two experimental plots at Troubsko and Vatín, Czech Republic during June and July in 2015. Samples were collected of the four forage legume species perennial red clover (variety "Amos"), alfalfa (variety "Holyně"), and annuals Persian clover and Alexandrian clover. Forage was sampled twice at regular three to four day intervals leading up to harvest and a third time on the day of harvest. Fresh and wilted material was analyzed using liquid chromatography-mass spectrometry (LC-MS). Higher levels ( p < 0.05) of isoflavones biochanin A (3.697 mg·g (-1) of dry weight) and formononetin (4.315 mg·g (-1) of dry weight) were found in red clover than in other species. The highest isoflavone content was detected in red clover, reaching 1.001% of dry matter ( p < 0.05), representing a risk for occurrence of reproduction problems and inhibited secretion of animal estrogen. The phytoestrogen content was particularly increased in wilted forage. Significant isoflavone reduction was observed over three to four day intervals leading up to harvest.

Characterization of the Principal Constituents of Danning Tablets, a Chinese Formula Consisting of Seven Herbs, by an UPLC-DAD-MS/MS Approach

Danning Tablets are a traditional Chinese formula showing broad clinical applications in hepatobiliary diseases and containing a diversity of bioactive chemicals. However, the chemical profiling of the formula, which serves as the material foundation of its efficacy, is really a big challenge as Danning Tablets consist of seven herbs from different origins. An ultra-performance liquid chromatography coupled to diode array detection and electrospray ionization mass spectrometry (UPLC-DAD-ESI-MS/MS) approach was developed to characterize the principal polyphenol constituents in the formula. As a result, a total of 32 constituents, including 14 anthraquinones and their glucosides, four anthrones, two naphthalene glycosides, two stilbenes and 10 flavonoids were identified based on their retention time, UV absorption and MS/MS fragmentation patterns. The sources of these compounds were also illustrated. Most of the bioactive anthraquinone derivatives were found in Rhei Radix et Rhizoma or Polygoni Cuspidati Rhizoma et Radix, which are the Emperor drugs in the formula for its clinic usage. These findings indicate the merit of using this integrated UPLC-DAD-ESI-MS/MS approach to rapidly illustrate the chemical foundation of complex formulas. The present study will facilitate the quality control of Danning Tablet formulas as well as the individual herbs.

Isoflavones in food supplements: chemical profile, label accordance and permeability study in Caco-2 cells

Consumers nowadays are playing an active role in their health-care. A special case is the increasing number of women, who are reluctant to use exogenous hormone therapy for the treatment of menopausal symptoms and are looking for complementary therapies. However, food supplements are not clearly regulated in Europe. The EFSA has only recently begun to address the issues of botanical safety and purity regulation, leading to a variability of content, standardization, dosage, and purity of available products. In this study, isoflavones (puerarin, daidzin, genistin, daidzein, glycitein, genistein, formononetin, prunetin, and biochanin A) from food supplements (n = 15) for menopausal symptoms relief are evaluated and compared with the labelled information. Only four supplements complied with the recommendations made by the EC on the tolerable thresholds. The intestinal bioavailability of these compounds was investigated using Caco-2 cells. The apparent permeability coefficients of the selected isoflavonoids across the Caco-2 cells were affected by the isoflavone concentration and product matrix.

A robust analytical method for measurement of phytoestrogens and related metabolites in serum with liquid chromatography tandem mass spectrometry

A sensitive and robust method using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for quantitation of 13 phytoestrogens and related metabolites in rat serum samples. A new type of column, the Kinetex core-shell C18 column, was applied for rapid separation of the target analytes in 10min. Two enzymes, sulfatase H-1 and gulcuronidase H-5 from Helix pomatia were compared on the efficiency of releasing the conjugated forms of the target analytes to their free forms in serum samples. The method detection limit (MDL) defined as three times the signal to noise ratio in spiked serum matrix-based solutions was in the range of 0.1-3.5ng/mL. The linear dynamic calibration was in the broad range of 0.2-500ng/mL for all target compounds. Thirty-two rat serum samples from the rats that were fed with diets containing either casein or soy protein isolates with various amounts of isoflavones for 8 weeks were analyzed for the target analytes with the developed method. Nine target analytes were detected in the serum samples. Those detectable compounds are all the metabolites of the dietary isoflavones, suggesting that the diet isoflavones were mostly metabolized to their metabolites in rat.

Neutral Loss Ion Mapping Experiment Combined with Precursor Mass List and Dynamic Exclusion for Screening Unstable Malonyl Glucoside Conjugates

Malonates are one type of the acylation conjugates and found abundantly in ginseng and soybean. Malonyl conjugates of ginsenosides and isoflavone glycosides were often considered as the characteristic components to evaluate various species and different forms of ginseng and soybean products because of their thermal instability. Another famous isoflavonoid-rich leguminous traditional Chinese medicine (TCM), named Puerarin lobata (Gegen), has also been reported to contain malonyl daidzin and malonyl genistin. However, the conjugates were found to present in very low amount and particularly unstable in the negative ion mode scan using LTQ Orbitrap mass spectrometry with electrospray ionization (ESI). In order to screen and characterize the malonyl conjugates in Gegen, a specific method was designed and developed combining neutral loss ion mapping (NLIM) experiment and precursor mass list (PL) triggered data dependent acquisition (DDA). Along with the activation of dynamic exclusion (DE), the method was proven to be specific and efficient for searching the malonate derivatives from Gegen. Two samples were examined by the established method. A total of 66 compounds were found, and 43 of them were malonates of isoflavone glycoside. Very few compounds were reported previously in Gegen. The results are helpful to understand the constituents of Gegen with more insight. The study not only provided a method for analyzing the malonyl conjugates from complex matrices but also explored a way to trace other low amount components in TCMs.

Clovamide and Flavonoids from Leaves of Trifolium pratense and T. pratense subsp. nivale Grown in Italy

The phenolic content and composition in leaves of Trifolium pratense (red clover) and T. pratense subsp. nivale (snow clover) grown in Italy were evaluated by means of ultraperformance liquid chromatography (UPLC) coupled with photodiode array and mass spectrometry detectors. Compound identification was based on UV and MS data comparing results with those of reference compounds. Quantitative evaluation of all detected compounds was based on calibration curves obtained with available standards. Several phenolics were identified in both extracts, including clovamide, flavonols and isoflavones as their glycosilated and malonated derivatives. The total phenolic content was higher in red clover (53.7 ± 2.2 mg/g dry weight) than in snow clover (44.4 ± 4.9 mg/g dry weight). Red clover contained higher amounts of clovamide and isoflavones (15.6 ± 0.6 and 24.6 ± 1.6 mg/g dry weight, respectively) than snow clover (8.2 ± 0.1 mg/g and 16.9 ± 0.4 mg/g dry weight, respectively), while flavonols were quantified almost in the same amount in both extracts (13.2 ± 0.6 mg/g and 15.8 ± 0.6 mg/g dry weight in red clover and snow clover, respectively). Red clover was characterized by the presence of quercetin, formononetin and biochanin A derivatives as the most abundant flavonoids, whereas snow clover was characterized by higher amounts of quercetin and prunetin derivatives. This investigation, conducted for the first time on phenolics from T. pratense subsp. nivale, revealed the presence in this plant of several flavonoid derivatives the same as in T. pratense. The higher amount of prunetin in snow clover suggest a possible role of this isoflavone as a chemotaxonomic marker for this subspecies. Moreover, snow clover may represent an interesting new source of natural isoflavones with a different concentration pattern than in red clover.

Determination of the isoflavone composition and estrogenic activity of commercial dietary supplements based on soy or red clover

Dietary supplements high in isolated isoflavones are commercially available for human consumption primarily to alleviate menopausal symptoms in women. The isoflavone composition, quantity and importantly their estrogenic potency are poorly standardised and can vary considerably between different products. The aim of this study was to analyse the isoflavone composition of 11 dietary supplements based on soy or red clover using the HPLC/MS/MS technique. Furthermore, we investigated the transactivational potential of the supplements on the estrogen receptors (ER), ERα and ERβ, performing luciferase reporter gene assays. As expected, we found that the isoflavone composition varies between different products. The measured total isoflavone contents in various supplements were mostly comparable to those claimed by the manufacturers in their product information. However expressing the isoflavone content as isoflavone aglycone equivalents, soy-based supplements had a clearly lower quantity compared to the manufacturer information. All supplements transactivated more or less ERα and ERβ with a preference for ERβ. The transactivational efficiency exceeded partly the maximal 17β-estradiol induced ER activation. While the different soy-based supplements revealed similar transactivation potential to both ERs, red clover-based supplements differed considerably. We conclude that different commercial dietary supplements based on soy or red clover vary in their isoflavone composition and quantity. They are estrogenically active, although especially the red clover-based supplements show considerable differences in their estrogenic potential to ERα and ERβ. Thus, different isoflavone-rich products cannot be necessarily compared regarding possible biological effects.

Mutagenic potential of the isoflavone irilone in cultured V79 cells

After consumption of red clover-based dietary supplements, plasma concentrations of the isoflavone irilone (IRI) equal that of the well-investigated daidzein. Since some isoflavones are genotoxic, the potential of IRI to induce mutations was investigated. Gene mutations were determined by hypoxanthine-guanine phosphoribosyltransferase (HPRT) assay and sequencing of mutant cDNA, chromosome and genome mutations by micronucleus assay complemented by immunochemical staining of centromere proteins and microtubules in cultured V79 cells. Cell proliferation was monitored by electronic cell counting, flow cytometry and fluorescence microscopy. IRI did not affect the mutant frequency in the Hprt locus but altered the mutation spectrum by increasing the proportion of deletions and decreasing that of base pair substitutions. Induction of chromosome mutations was supported by a slight but significant increase in the number of micronucleated cells containing chromosomal fragments despite activation of three cell cycle checkpoints possibly interfering with micronuclei formation. Moreover, IRI exhibited a strong aneugenic potential characterized by disrupted mitotic spindles, mitotic arrest, and asymmetrical cell divisions leading to chromosome loss, nuclear fragmentation as well as mitotic catastrophe. Thus, IRI might be another isoflavone to be taken into account in safety assessment of dietary supplements.

Ultrasound-assisted dynamic extraction coupled with parallel countercurrent chromatography for simultaneous extraction, purification, and isolation of phytochemicals: application to isoflavones from red clover

A novel procedure comprising ultrasonic-assisted dynamic extraction (UADE) coupled with two countercurrent-chromatography systems (parallel countercurrent chromatography, PCCC) was developed. This technique offers the possibility for simultaneous extraction, solvent configuration, purification, and isolation of target compounds. This new approach was applied to the fractionation and purification of isoflavones from red clover. The two-phase solvent system was prepared by automating the equipment. The lower aqueous phase of the two-phase solvent system was used as the UADE solution and as the mobile phase for PCCC. After the extraction and purification steps, the purified sample was pumped into the countercurrent chromatography 1 (CCC1) column for the first isolation step. During CCC1 separation, the sample was enriched and purified and then pumped into the CCC2 column for the second isolation step. After completion of the first cycle of UADE-PCCC steps, the second-cycle experiments were performed. Using this sequence, five target compounds, daidzein, prunetin, genistein, irilone, and maackiain, with >95.31 % purity were successfully extracted and isolated using the two-phase solvent system of n-hexane-ethyl acetate-ethanol-water (0.623:1.00:0.99:1.246, v/v). With this instrumental setup, scientific and systematic extraction and isolation of natural products was achieved, and this technique has great potential for industrial application. Graphical Abstract Simplified schematic of instrumental setup of UADE combined with two HSCCC instruments.

Free radical scavenging actions of three Trifolium species in the protection of blood plasma antioxidant capacity in vitro

CONTEXT

Three clover [Trifolium L. (Leguminosae)] species were selected on the basis of data from traditional medicine, phytochemical profiles, and agricultural significance.

OBJECTIVE

The in vitro evaluations of free radical scavenging properties, ferric reducing abilities, and antioxidant effects of extracts from T. pratense L. (crude extract and phenolic fraction), T. pallidum L., and T. scabrum L. (phenolic fractions) were performed.

MATERIALS AND METHODS

Activities of the Trifolium extracts were determined at their final concentrations of 1.5-50 µg/ml. Free radical scavenging properties of methanol extract solutions were estimated by the reduction of DPPH(•) and ABTS(•) radicals. Measurements of the total antioxidant capacity (TAC) were carried out to assess the antioxidant activities of the extracts in human blood plasma under conditions of oxidative stress, induced by 200 μM peroxynitrite.

RESULTS

The phenolic fraction of T. pratense displayed the strongest ABTS(•) and DPPH(•) radical scavenging effects (EC50 value of 21.69 and 12.27 µg/ml, respectively). The EC50 value for T. pallidum extract attained 29.77 and 30.06 µg/ml. The two remaining extracts were less potent scavengers (EC50 value higher than 50 µg/ml). Similar differences were obtained during evaluation of the ferric reducing abilities. Analysis of antioxidant properties of the extracts in blood plasma did not provide such evident differences in their actions, however, it indicated that the T. pratense phenolic fraction displayed the strongest effect.

CONCLUSIONS

The examined Trifolium extracts partly protected blood plasma and enhanced its non-enzymatic antioxidant defense against harmful action of peroxynitrite in vitro.

Phytochemical Analysis and Anti-Inflammatory Activity of the Extracts of the African Medicinal Plant Ximenia caffra

A method was developed for identification and quantification of polyphenols in the leaves of Ximenia caffra using HPLC/UV/MS. Based on analyzing the MS and UV data and in comparison to the authentic standards, a total of 10 polyphenols were identified and quantified, including gallic acid, catechin, quercetin, kaempferol, and their derivatives. The total content of these compounds was found to be approximately 19.45 mg/g in the leaf and the most abundant is quercetin-rutinoside (9.08 mg/g). The total phenolic content as measured by Folin-Ciocalteu assay was 261.87 ± 7.11 mg GAE/g and the total antioxidant capacity as measured in vitro was 1.46 ± 0.01 mmol Trolox/g. The antiproliferative effect of the leaf extract was measured by MTS assay with IC50 value of 239.0 ± 44.5 μg/mL. Cell-based assays show that the leaf extract inhibits the mRNA expression of proinflammatory genes (IL-6, iNOS, and TNF-α) by using RT-qPCR, implying its anti-inflammatory effects. It was further demonstrated that the underlying therapeutic mechanism involves the suppression of NF-κB, a shared pathway between cell death and inflammation.