New Aspect of Composition and Biological Properties of Glechoma hederacea L. Herb: Detailed Phytochemical Analysis and Evaluation of Antioxidant, Anticoagulant Activity and Toxicity in Selected Human Cells and Plasma In Vitro.

It is known that phenolic compounds can alleviate the negative impact of oxidative stress and modulate hemostasis. However, the effect of extracts and phenolics from Glechoma hederacea L. on the biomarkers of these processes is not well documented. The aim of our study was to investigate the in vitro protective effects of one extract and three fractions (20, 60, and 85% fraction) from G. hederacea L. on oxidative stress and hemostasis. Phytochemical analysis showed that aerial parts of G. hederacea L. are rich in both phenolic acids (such as rosmarinic acid, neochlorogenic acid, and chlorogenic acid) and flavonoids (mainly rutin and glycoside derivatives of apigenin, quercetin, and luteolin). We observed that the 85% fraction (at three concentrations: 5, 10, and 50 µg/mL) inhibited protein carbonylation. Moreover, the extract and 85% fraction (at the concentration of 50 µg/mL) could reduce lipid peroxidation. All fractions and the extract were very effective at decreasing H2O2-induced DNA damage in PBM cells. The 85% fraction had the strongest protective potential against DNA oxidative damage. We also observed that the extract and fractions decreased PBM cell viability to a maximum of 65% after 24 h incubation. Our results indicate that the 85% fraction showed the strongest antioxidant potential. The main component of the 85% fraction was apigenin (26.17 ± 1.44 mg/g), which is most likely responsible for its strong antioxidant properties.

Effect of Paulownia Leaves Extract Levels on In Vitro Ruminal Fermentation, Microbial Population, Methane Production, and Fatty Acid Biohydrogenation.

Paulownia is a fast-growing tree that produces a huge mass of leaves as waste that can be used as a feed source for ruminants. The previous study showed that phenolic compounds were the most active biological substances in Paulownia leaves, which affected the ruminal parameters and methane concentration. However, there are no scientific reports on the Paulownia leaves extract (PLE) containing phenolic compounds for their mode of action in the rumen. Phenolics constituted the main group of bioactive compounds in PLE (84.4 mg/g dry matter). PLE lowered the concentration of ammonia, modulated the VFA profile in the ruminal fluid, and decreased methane production. The PLE caused a significant reduction of in vitro dry matter degradability, reduced the number of methanogens and protozoa, and affected selected bacteria populations. PLE had a promising effect on the fatty acid profile in the ruminal fluid. Paulownia as a new dietary component or its extract as a feed additive may be used to mitigate ruminal methanogenesis, resulting in environmental protection and reducing ruminal biohydrogenation, improving milk and meat quality.

Qualitative and Quantitative Analysis of Secondary Metabolites in Morphological Parts of Paulownia Clon In Vitro 112® and Their Anticoagulant Properties in Whole Human Blood.

It is not easy to find data in the scientific literature on the quantitative content of individual phytochemicals. It is possible to find groups of compounds and even individual compounds rather easily, but it is not known what their concentration is in cultivated or wild plants. Therefore, the subject of this study was to determine the content of individual compounds in the new Paulownia species, Oxytree, developed in a biotechnology laboratory in 2008 at La Mancha University in Spain. Six secondary metabolites were isolated, and their chemical structure was confirmed by spectral methods. An analytical method was developed, which was then used to determine the content of individual compounds in leaves, twigs, flowers and fruits of Paulownia Clon in Vitro 112®. No flavonoids were found in twigs and fruits of Oxytree, while the highest phenylethanoid glycosides were found in twigs. In this study, we also focused on biological properties (anticoagulant or procoagulant) of extract and four fractions (A-D) of different chemical composition from Paulownia Clon in Vitro 112 leaves using whole human blood. These properties were determined based on the thrombus-formation analysis system (T-TAS), which imitates in vivo conditions to assess whole blood thrombogenecity. We observed that three fractions (A, C and D) from leaves decrease AUC10 measured by T-TAS. In addition, fraction D rich in triterpenoids showed the strongest anticoagulant activity. However, in order to clarify the exact mechanism of action of the active substances present in this plant, studies closer to physiological conditions, i.e., in vivo studies, should be performed, which will also allow to determine the effects of their long-term effects.

In vitro antiplatelet activity of extract and its fractions of Paulownia Clone in Vitro 112 leaves.

BACKGROUND: Paulownia Clone in Vitro 112, also known as Oxytree is a hybrid of Paulownia elongata and Paulownia fortunei, developed under laboratory conditions. Its seeds are sterile, making it a noninvasive variety that can only be propagated in the laboratory. In China, species from the Paulownia genus (Paulowniaceae) are widely used in traditional medicine for the treatment of infectious diseases, such as gonorrhea and erysipelas. It has a broad spectrum of bioactivity, including neuroprotective, antioxidant, antibacterial, antiphlogistic, antiviral, and cytotoxic actions. However, the antiplatelet potential of Paulownia Clone in Vitro 112 has not yet been described. STUDY DESIGN: The aim of our study was thus to examine the effect of an extract and four fractions from leaves of Paulownia Clone in Vitro 112 on various parameters of platelet activation in an in vitro model. METHODS: Composition of the investigated extract and fractions was determined by UHPLC-UV-MS. The following parameters of platelet activation were investigated: nonenzymatic lipid peroxidation in resting platelets; enzymatic lipid peroxidation (AA metabolism) in platelets activated by thrombin; superoxide anion (O2-.) generation in the resting and activated platelets; platelet adhesion to collagen type I and fibrinogen; platelet aggregation stimulated by various physiological agonists, such as ADP, collagen, and thrombin. The effect of the extract and fractions on extracellular LDH activity, a marker of cell damage, was also determined. RESULTS: Verbascoside a phenylethnanoid glycoside, was the main secondary metabolite of the extract from leaves of oxytree (constituting approximately 45 % of all compounds). There were also iridoids, such as catalpol, aucubin, and 7-hydroxytomentoside, as well as flavonoids, such as luteolin and apigenin glycosides. Moreover, the extract had stronger antiplatelet properties than the fractions. For example, the extract at 10 µg/mL inhibited five parameters of platelet activation. CONCLUSIONS: Our results show that Paulownia Clone in Vitro 112 leaves are a new valuable source of compounds with antiplatelet potential.

Bersaldegenin-1,3,5-orthoacetate induces caspase-independent cell death, DNA damage and cell cycle arrest in human cervical cancer HeLa cells.

CONTEXT: Bufadienolide compounds occur in many plants and animal species and have strong cardiac and anti-inflammatory properties. The compounds have been recently investigated for cytotoxic and antitumor activity. OBJECTIVE: The cytotoxic effect of bersaldegenin-1,3,5-orthoacetate - a bufadienolide steroid occuring in plants from Kalanchoe genus (Crassulaceae), was evaluated with cervical cancer HeLa cells in vitro. MATERIALS AND METHODS: The cytotoxic activity of the compound (at 0.1-20.0 µg/mL) on the cells was determined by Real-Time Cell Analysis (RTCA) system for 24 h. The estimation of cell cycle arrest, reactive oxygen species (ROS) production, reduction of mitochondrial membrane potential (MMP), and caspases-3/7/9 activity in the HeLa cells treated with the compound was done by flow cytometry and luminometric technique. DNA damage in the cells was estimated by immunofluorescence staining and the comet assay with etoposide as a positive control. RESULTS: The compound had strong effect on the cells (IC50 = 0.55 µg/mL) by the suppression of HeLa cells proliferation in G2/M phase of cell cycle and induction of cell death through double-stranded DNA damage and reactive oxygen species overproduction. Furthermore, we did not observe an increase in the activity of caspase-3/7/9 in the treated cells as well as a decrease in cellular mitochondrial membrane potential. Gene expression analysis revealed the overexpression of NF-Kappa-B inhibitors genes (>2-fold higher than control) in the treated cells. CONCLUSIONS: Bersaldegenin-1,3,5-orthoacetate induces cell cycle arrest and caspase-independent cell death through double-stranded DNA damage. These results are an important step in further studies on cell death signalling pathways induced by bufadienolides.

Comparative Phytochemical, Antioxidant, and Hemostatic Studies of Extract and Four Fractions from Paulownia Clone in Vitro 112 Leaves in Human Plasma.

Background: The Paulownia Clone in Vitro 112, known as oxytree or oxygen tree, is a hybrid clone of the species Paulownia elongata and Paulownia fortunei (Paulowniaceae). The oxytree is a fast-growing hybrid cultivar that can adapt to wide variations in edaphic and climate conditions. In this work, Paulownia Clone in Vitro 112 leaves were separated into an extract and four fractions (A-D) differing in chemical content in order to investigate their chemical content using LC-MS analysis. The extract and fractions were also evaluated for their anticoagulant and antioxidant properties in a human plasma in vitro. Results: The Paulownia leaf extract contained mainly phenolic compounds (e.g., verbascoside), small amounts of iridoids (e.g., aucubin or 7-hydroxytometoside) and triterpenoids (e.g., maslinic acid) were also detected. Our results indicate that the extract and fractions have different effects on oxidative stress in human plasma treated with H2O2/Fe in vitro, which could be attributed to differences in their chemical content. For example, the extract and all the fractions, at the two highest concentrations of 10 and 50 µg/mL, significantly inhibited the plasma lipid peroxidation induced by H2O2/Fe. Fractions C and D, at all tested concentrations (1-50 µg/mL) were also found to protect plasma proteins against H2O2/Fe-induced carbonylation. The positive effects of fraction C and D were dependent on the dose. Conclusions: The extract and all four fractions, but particularly fractions C and D, which are rich in phenolic compounds, are novel sources of antioxidants, with an inhibitory effect on oxidative stress in human plasma in vitro. Additionally, the antioxidant potential of fraction D may be associated with triterpenoids.

Identification of Flavonoids and Bufadienolides and Cytotoxic Effects of Kalanchoe daigremontiana Extracts on Human Cancer Cell Lines.

Kalanchoe species are well-known medicinal plants used in traditional medicine as anti-inflammatory and analgesic remedies. Recently, it has been reported that Kalanchoe plants have cytotoxic properties; however, data on traditional use of these plants in tumor treatment are extremely limited. Kalanchoe daigremontiana is one of the most popular species cultivated in Europe, and it is used, among other things, as a remedy in treating skin injuries and wounds. Studies on the biological activity of this species are scarce, and there is a lack of data on the cytotoxic activity of K. daigremontiana extracts on epithelial cancer cells in the literature. In our present study, we analyzed the phytochemical composition of K. daigremontiana ethanol extract and fractions-water and dichloromethane-by the HPLC-DAD-ESI-MS method and estimated cytotoxic activity of the extracts on human adenocarcinoma (HeLa), ovarian (SKOV-3), breast (MCF-7), and melanoma (A375) cell lines by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, real-time cell analyzer (RTCA), and flow cytometry. We identified 6 bufadienolide compounds and 19 flavonoids, mostly kaempferol, quercetin, isorhamnetin, and myricetin glycosides, of which only 3 flavonoids have been identified in K. daigremontiana to date. Other flavonoids that were characterized in our study have not yet been found in this plant. The ethanol extract and water fraction of K. daigremontiana did not show significant cytotoxic activity on the tested cell lines. In contrast, the dichloromethane fraction showed the strongest activity against all cell lines with IC50 values of ≤ 10 µg/mL. The results indicated that this activity is mainly due to the presence of bersaldegenin-1,3,5-orthoacetate.

Effect of synthetic surfactants and soapwort (Saponaria officinalis L.) extract on skin-mimetic model lipid monolayers.

The effect of a saponin-rich extract from rhizomes of Soapwort (Saponaria officinalis L) and four synthetic surfactants: sodium lauryl sulphate (SLS), sodium laureth sulphate (SLES), ammonium lauryl sulphate (ALS) and cocamidopropyl betaine (CAPB) on two model lipid monolayers is analyzed using surface pressure, surface dilatational rheology and fluorescence microscopy. The following monolayers were employed: dipalmitoylphosphatidylcholine/cholesterol mixture in a molar ratio of 7:3 (DPPC/CHOL) and Ceramide [AP]/stearic acid/cholesterol in a molar ratio of 14:14:10 (CER/SA/CHOL). They mimicked a general bilayer structure and an intercellular lipid mixture, respectively. Both lipid mixtures on Milli-Q water were first compressed to the initial surface pressure, Π0 = 30 mN/m and then the subphase was exchanged with the respective (bio)surfactant solution at 1% (w/w). All four synthetic surfactants behaved in a similar way: they increased surface pressure to about 40 mN/m and reduced the storage modulus of surface dilational surface rheology, E', to the values close to zero. The corresponding fluorescence microscopy pictures confirmed that the lipids mimicking the stratum corneum components were almost completely removed by the synthetic surfactants under the present experimental conditions. The components of the Soapwort extract (SAP) increased surface pressure to significantly higher values than the synthetic surfactants, but even more spectacular increase was observed for the storage modulus of the SAP-penetrated lipid monolayers (up to E'= 715 mN/m).

Bufadienolides from Kalanchoe daigremontiana modulate the enzymatic activity of plasmin - In vitro and in silico analyses.

Plasmin (EC 3.4.21.7) is a key enzyme of the fibrinolytic system, responsible for the degradation of fibrin clot and maintaining blood fluidity. Hence, alterations of the fibrinolytic capacity of blood plasma may contribute to thrombotic or bleeding complications. The aim of this study was to determine effects of a bufadienolide-rich fraction, isolated from roots of Kalanchoe daigremontiana (0.05-50 µg/ml) on enzymatic properties of plasmin. Hydrolysis of a synthetic substrate S-2251 (H-D-Valyl-l-leucyl-l-lysine-p-nitroaniline dihydrochloride) by plasmin revealed that the bufadienolide-rich fraction had a diverse effect on this enzyme, dependently on the concentration range. While the lower concentrations of the examined fraction (0.05-2.5 µg/ml) significantly enhanced the amidolytic activity of plasmin, at 25-50 µg/ml concentrations, the enzyme was evidently inhibited (by about 60%). The Lineweaver-Burk plot indicated on an uncompetitive inhibition of plasmin. Inhibitory effects (up to 80%) were also found in the streptokinase-induced plasminogen activation to plasmin. Docking results suggest that only some of compounds (mostly bersaldegenin 1-acetate (10), bryotoxin (13) and hovetrichoside C (17)) were bound to plasminogen/plasmin, depending on the presence or absence of the substrate in the active site. The obtained findings suggest allosteric regulation of plasminogen activation and plasmin activity by components of the examined fraction.

Phenolic fractions from nine Trifolium species modulate the coagulant properties of blood plasma in vitro without cytotoxicity towards blood cells.

OBJECTIVE: The study covers an evaluation of the influence of extracts (1-50 µg/ml), isolated from aerial parts of nine Trifolium L. species (i.e. T. alexandrinum, T. fragiferum, T. hybridum, T. incarnatum, T. pallidum, T. pratense, T. resupinatum var. majus, T. resupinatum var. resupinatum and T. scabrum) on haemostatic properties of blood plasma. METHODS: The clot formation and fibrinolysis assay (CFF), blood clotting times, the extrinsic and intrinsic coagulation pathway-dependent polymerization of plasma fibrin were measured. The effects of plant extracts on amidolytic activity of thrombin were also evaluated and compared with argatroban, an antithrombotic drug. Cytotoxicity was assessed in a model of blood platelets and as the viability of peripheral blood mononuclear cells. KEY FINDINGS: While no changes in blood clotting times or fibrinolytic properties of blood plasma were found, some fractions impaired the blood plasma coagulation induced by the intrinsic coagulation pathway. Reduction in the maximal velocity of fibrin polymerization was also observed in the clot formation and fibrinolysis assay. No cytotoxicity of Trifolium extracts towards the investigated cells was recorded. CONCLUSIONS: The most efficient anticoagulant activity in plasma was found for T. fragiferum and T. incarnatum extracts, while the T. alexandrinum fraction was the most effective inhibitor of thrombin amidolytic activity.

Bufadienolides from Kalanchoe daigremontiana as thrombin inhibitors-In vitro and in silico study.

Thrombin is an active plasma coagulation factor II, critical for the formation of fibrin clot during blood coagulation. For that reason, this protein is also a crucial target for different anti-thrombotic therapies. The work is based on in vitro evaluation of the inhibitory effect of bufadienolide-rich fraction, isolated from roots of Kalanchoe daigremontiana (1-50µg/ml) on enzymatic properties of a serine proteinase - thrombin. The efficacy of the inhibition of amidolytic activity of thrombin (measured as a hydrolysis of the chromogenic substrate S-2238, Chromogenix) attained about 10 and 66%, respectively. The IC50, established for the examined bufadienolide fraction was 2.79µg/ml, while the IC50 calculated for argatroban (reference compound) was 0.78µg/ml. Linearization conducted using Lineweaver-Burk plot indicated that the K. daigremontiana fraction contains compounds that are uncompetitive inhibitors of thrombin. K. daigremontiana fraction was also able to reduce the proteolytic activity of thrombin towards its physiological substrate, i.e. fibrinogen. Additionally, this study is supported by in silico analysis of interactions of the most common compounds, identified in the examined in Kalanchoe extract to crystal structure of this enzyme.

Antioxidant efficacy of Kalanchoe daigremontiana bufadienolide-rich fraction in blood plasma in vitro.

CONTEXT: The main source of bufadienolides is toad venom; however, plants such as members of Kalanchoe Adans. (Crassulaceae) genus may also synthesize these bioactive substances. OBJECTIVE: This is the first study on antioxidant effects and cytotoxicity of bufadienolide-rich fraction isolated from Kalanchoe daigremontiana Raym.-Hamet & H. Perrier. MATERIALS AND METHODS: The methanolic fraction was extracted from the plant roots and contained 0.48 mg bufadienolides/mg of dry mass (11α,19-dihydroksytelocinobufagin, bersaldegenin-1-acetate, bersaldegenin-1,3,5-orthoacetate, 19-(acetyloxy)-3ß,5ß,11α,14-tetrahydroxyl-12-oxo-bufa-20,22-dienolide and 19-(acetyloxy)-1ß,3ß,5ß,14-tetrahydroxyl-bufa-20,22-dienolide, mainly). The cytotoxicity of K. daigremontiana fraction was evaluated in an in vitro experimental model of blood platelets. The viability of blood platelets was determined on the basis of a release of lactate dehydrogenase. RESULTS: The fraction scavenged DPPH• radicals, with EC50 of 21.80 µg/mL. Studies on an experimental model of blood plasma under peroxynitrite-induced oxidative stress revealed that the plant preparation had moderate antioxidant properties. Levels of 3-nitrotyrosine and thiol groups indicated that the protective effect of K. daigremontiana was significant mainly for its concentration of 50 µg/mL. No effect was found in prevention of oxidation of low-molecular plasma thiols (glutathione, cysteine and cysteinylglycine). Simultaneously, measurements of lipid hydroperoxides and thiobarbituric acid-reactive substances (TBARS) indicated that the examined fraction might be effective antioxidant at broader concentration range, that is 1-5 and 25-50 µg/mL for hydroperoxides and TBARS generation, respectively. No cytotoxicity was observed at the concentration range of 1-50 µg/mL. CONCLUSIONS: Based on the obtained results, we suggest that antioxidant activity may additionally contribute to beneficial properties of K. daigremontiana-derived extracts.

New Bufadienolides Isolated from the Roots of Kalanchoe daigremontiana (Crassulaceae).

An aqueous extract from the roots of Kalanchoe daigremontiana turned out to be a rich source of bufadienolides. The existing literature data relate mainly to the aerial parts of Kalanchoe but there is no information about the metabolic profile of the roots, which are also used in traditional medicine. Our investigation concerning the roots of K. daigremontiana led to the isolation and characterization of eight new bufadienolides, namely 1ß,3ß,5ß,14ß,19-pentahydroxybufa-20,22-dienolide (1), 19-(acetyloxy)-1ß,3ß,5ß,14ß-tetrahydroxybufa-20,22-dienolide (2), 3ß-O-α-l-rhamno-pyranosyl-5ß,11α,14ß,19-tetrahydroxybufa-20,22-dienolide (3), 19-(acetyloxy)-3ß,5ß,11α,14ß-tetrahydroxybufa-20,22-dienolide (4), 3ß,5ß,11α,14ß,19-pentahydroxy-12-oxo-bufa-20,22-dienolide (5), 19-(acetyloxy)-3ß,5ß,11α,14ß-tetrahydroxy-12-oxo-bufa-20,22-dienolide (6), 19-(acetyloxy)-1ß,3ß,5ß,11α,14ß-pentahydroxy-12-oxo-bufa-20,22-dienolide (7) and 1ß-(acetyloxy)-3ß,5ß,11α,14ß,19-pentahydroxy-12-oxo-bufa-20,22-dienolide (8), together with seven known compounds: 11α,19-dihydroxytelocinobufagin (9), bersaldegenin-1-acetate (10), daigredorigenin-3-acetate (11), bersaldegenin-1,3,5-orthoacetate (12), bryotoxin B (13), bryophyllin B (14) and bersaldegenin (15). The structures were established applying extensive 1D- and 2D-NMR and MS spectroscopic analyses.

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.

New pharmacological properties of Medicago sativa and Saponaria officinalis saponin-rich fractions addressed to Candida albicans.

The antifungal activity of the saponin-rich fractions (SFs) from Medicago sativa (aerial parts and roots) and Saponaria officinalis (used as a well-known source of plant saponins) against Candida albicans reference and clinical strains, their yeast-to-hyphal conversion, adhesion, and biofilm formation was investigated. Direct fungicidal/fungistatic properties of the tested phytochemicals used alone, as well as their synergy with azoles (probably resulting from yeast cell wall instability) were demonstrated. Here, to the best of our knowledge, we report for the first time the ability of saponin-rich extracts of M. sativa and S. officinalis to inhibit C. albicans germ tube formation, limit hyphal growth, reduce yeast adherence and biofilm formation, and eradicate mature (24 h) Candida biofilm. Moreover, M. sativa SFs (mainly obtained from aerial parts), in the range of concentrations which were active modulators of Candida virulence factors, exhibited low cytotoxicity against the mouse fibroblast line L929. These properties seem to be very promising in the context of using plant-derived SFs as potential novel antifungal therapeutics supporting classic drugs or as ingredients of disinfectants.

Ultraperformance liquid chromatography tandem mass spectrometry determination of cyanogenic glucosides in Trifolium species.

Cyanogenic glucosides were analyzed by ultra-high-performance liquid chromatography combined with mass spectrometry in 88 Trifolium species grown at the same site. On the basis of the occurrence of cyanogenic glucosides and the linamarin/lotaustralin ratio species could be grouped into five clusters. Cluster C1 included 37 species, which did not contain cyanogens. Cluster C2 (22 species) included plants containing only lotaustralin. In clusters C3 (14 species), C4 (13 species), and C5 (2 species) both linamarin and lotaustralin were present but at different ratios. In C3 and C4 the linamarin/lotaustralin ratio was below 1, whereas in cluster C5 the ratio was much higher. Generally, the total content of cyanogens was below 500 µg/g dry matter. Only in Trifolium repens var. biasoletti and Trifolium montanum extremely high cyanogen concentrations were observed. There was no general rule of occurrence of cyanogens. Samples of the same species from different countries accumulated cyanogens or could be free of these compounds.

Antioxidative effects of extracts from Trifolium species on blood platelets exposed to oxidative stress.

Clovers (Trifolium) may possess a significant therapeutic potential, but the effects of compounds from these plants on blood platelets and haemostasis have been poorly recognized. The present study was designed to evaluate the antioxidative action of extracts from three species of clovers: Trifolium pratense, Trifolium pallidum and Trifolium scabrum in the protection of human blood platelets in vitro. Platelet suspensions were pre-incubated with crude extract and phenolic fraction of T. pratense or phenolic fractions of T. scabrum and T. pallidum, at the final concentrations of 0.5-50 µg/ml. Then, for the induction of oxidative stress, 100 µM peroxynitrite was added. The antioxidative activity of plant extracts was assessed by measurements of the level of 3-nitrotyrosine, thiol groups and lipid peroxidation products (hydroperoxides and thiobarbituric acid-reactive substances). Despite the significant differences in the composition of the investigated extracts, we observed antioxidative effects of all used mixtures. The presence of Trifolium extracts considerably reduced the peroxynitrite-mediated modifications of proteins and diminished peroxidation of lipids in platelets. Our results indicate on a strong antioxidative activity of the tested extracts-statistically significant effects were found even for the lowest concentrations (0.5 µg/ml) of all extracts. This action may be useful in the protection of blood components, very susceptible to oxidative modifications. The obtained results suggest that the examined clovers are a promising source of compounds, valuable for the protection against oxidative stress-induced damage to blood platelets.

Trifolium pallidum and Trifolium scabrum extracts in the protection of human plasma components.

Clovers (genus: Trifolium) have been used in traditional medicine by many cultures, but the biological activity of the most of these plants still remains unknown. The aim of our in vitro study was to assess the antioxidative action of phenolic extracts from aerial parts of Trifolium scabrum and Trifolium pallidum in human blood plasma, exposed to oxidative stress. In the present study we also demonstrate, for the first time the effects of the tested extracts on coagulative properties and fibrinolytic activity of blood plasma. The protective properties of the examined extracts (0.5-50 µg/ml) against peroxynitrite-induced oxidative stress were estimated by the measurements of 3-nitrotyrosine, thiol groups and the thiobarbituric acid-reactive substances levels. The extracts considerably prevented the oxidative and nitrative damage to plasma proteins. Even the lowest doses of the Trifolium extracts (0.5 µg/ml) were able to markedly reduce 3-nitrotyrosine formation (by about 50%) and to increase the level of -SH groups (by about 30%), in comparison to the plasma exposed to ONOO(-) in the absence of the extracts. The protective action of all the used concentrations of the Trifolium extracts in the prevention of lipid peroxidation was also found. The tested extracts influenced neither the coagulative properties nor fibrinolytic activity of plasma. Moreover, the extracts were able to significantly reduce the inhibitory effect of ONOO(-) on fibrinolytic activity of plasma (assessed with the use of a chromogenic substrate for plasmin).

New triterpenoid saponins from the roots of Saponaria officinalis.

Three new triterpenoid saponins (1-3), along with nine known saponins, were isolated from the roots of Saponaria officinalis L. Two of them: vaccaroside D (4) and dianchinenoside B (5) are known, but not previously reported for S. officinalis, and seven others: saponarioside C (6), D (7), F (8), G (9), I (10), K (11), and L (12) have been previously isolated from this plant. The structures of the new saponins were established as 3-O-beta-D-xylopyranosyl-16alpha-hydroxygypsogenic acid-28-O-[beta-D-glucopyranosyl-(1 -->6)-beta-D-glucopyranoside (1), 3-O-beta-D-xylopyranosyl-16alpha-hydroxygypsogenic acid-28-O-[beta-D-glucopyranosyl-(1-->3)]-[alpha-D-galactopyranosyl-(1-->6)-alpha-D-galactopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside (2) and 3-O-beta-D-xylopyranosyl-gypsogenic acid-28-O-[beta-D-glucopyranosyl-(1-->3)]-[6-O-(3-hydroxy-3-methylglutaryl)-beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside (3). Their structures were elucidated by extensive spectroscopic methods, including 1D- (1H, 13C) and 2D-NMR (D QF-COSY, TOCSY, ROESY, HSQC and HMBC) experiments, as well as high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), ESI-MS/MS and acid hydrolysis.

Phenolic fractions from Trifolium pallidum and Trifolium scabrum aerial parts in human plasma protect against changes induced by hyperhomocysteinemia in vitro.

Elevated concentration of homocysteine (Hcy) in human plasma, defined as hyperhomocysteinemia has been correlated with some diseases, such as cardiovascular, neurodegenerative, and kidney disorders. Homocysteine occurs in human plasma in several forms, including the most reactive form of Hcy - its cyclic thioester - homocysteine thiolactone (HTL), which represents up to 0.29% of plasma total Hcy. It is suggested that Hcy and HTL may also act as oxidants, but various polyphenolic antioxidants are able to inhibit the oxidative damage induced by Hcy or HTL. The aim of our present study was to investigate in vitro oxidative changes in human plasma induced by the model of hyperhomocysteinemia in the presence of the phenolic fractions from selected clovers (Trifolium pallidum and Trifolium scabrum aerial parts). Hyperhomocysteinemia was stimulated by a reduced form of Hcy (final dose 100 µM) or HTL (final dose 1 µM). The aim of our study was also to explain the effect of the phenolic fractions on the coagulation activity of human plasma treated with Hcy and its thiolactone. Tested phenolic fractions significantly inhibited the oxidative stress (measured by the total antioxidant level - TAS) in plasma treated with Hcy or HTL. The phenolic fractions from T. pallidum and T. scabrum also caused a distinct reduction of plasma lipid peroxidation (measured by the level of thiobarbituric acid reactive substance) induced by the model of hyperhomocysteinemia. Moreover, tested fractions modulated the coagulation properties of plasma treated with homocysteine and its thiolactone. It seems that antioxidative activities of the phenolic fractions from T. pallidum and T. scabrum aerial parts may be responsible for their medicinal properties during hyperhomocysteinemia.