The isoflavonoid tectorigenin has better antiplatelet potential than acetylsalicylic acid.

BACKGROUND: One reason for the lower incidence of cardiovascular diseases in Asian countries may be the high intake of isoflavonoids and their antiplatelet effects may be an important factor. To date, there is limited comparison of a range of isoflavonoids and knowledge of their effects at different levels of platelet aggregation. PURPOSE: To screen the antiplatelet effects of a number of isoflavonoids on the arachidonic acid based aggregation pathway and investigate how the antiplatelet activity might occur. METHODS: The antiplatelet effects were first screened in whole human blood where platelet aggregation was induced by arachidonic acid. Further analysis was targeted at search of the mechanism of action. RESULTS: Thirteen of the eighteen tested isoflavonoids had significant inhibitory effect on platelet aggregation in whole human blood. Genistein had the same potency as clinically used acetylsalicylic acid (ASA) while tectorigenin was clearly stronger than ASA. Further analyses showed that the effect of tectorigenin was not based on inhibition of cyclooxygenase-1 in contrast to ASA or thromboxane synthase but by competitive antagonism at thromboxane receptors. CONCLUSION: Tectorigenin is a more potent antiplatelet compound than ASA and thus an interesting substance for further testing.

Production of Podophyllotoxin by Plant Tissue Cultures of Juniperus virginiana.

Plant tissue cultures are a potential source of secondary metabolites. However, their production, when compared with intact plants, is usually lower. Phenylalanine, a biogenetic precursor of podophyllotoxin, was used to stimulate podophyllotoxin production in callus and suspension cultures of Juniperus virginiana L. The best phenylalanine effect on podophyllotoxin production was manifested in three-years-old callus cultures after a 21-days application of a 10 mmol/L concentration. A podophyllotoxin content of 0.15 mg/g DW was determined, which was about 400% higher in comparison with the control. The maximum content (0.48 mg/g DW) in newly derived suspension cultures (the 4' passage) was induced by 14-days application of a I mmol/L concentration; this was about 243% higher than the control. In one-year-old suspension cultures the highest podophyllotoxin content (0.56 mg/g DW) was recorded also after 14-days application of a I mmol/L concentration; this was about 211% higher than in the control cultures.

Plant Tissue Cultures of Juniperus virginiana.

Callus cultures of Juniperus virginiana L. (varieties 'Hetzii', 'Glauca', 'Grey Owl') were derived from fresh leaves of garden-grown trees on Schenk and Hildebrandt medium supplemented with 3.0 mg/L of α-naphthaleneacetic acid, 0.2 mg/L of kinetin and 15 mg/L of ascorbic acid. The growth characteristics of one-year-old and two-years-old cultures were determined. The maximum biomass in all varieties was achieved on the 35th day of the cultivation period. The increase in fresh weights of two-years-old callus cultures, when compared with one-year-old callus cultures, was as follows: variety 'Hetzii' by 25%, variety 'Glauca' by 29% and variety 'Grey Owl' by 49%. J. virginiana suspension cultures (varieties 'Hetzii', 'Glauca', 'Grey Owl') were derived from two-years-old callus cultures on Schenk and Hildebrandt medium supplemented with 3.0 mg/L of α-naphthaleneacetic acid, 0.2 mg/L of kinetin and 15 mg/L of ascorbic acid. The maximum biomass of all varieties was found on the 21st day of the cultivation period. These results indicate that a sub-cultivation interval of 35 days for callus cultures and of 21st days for suspension cultures can be recommended. The callus and suspension cultures of J. virginiana of the variety 'Glauca' have the best survivability and thus provide the most biomass.

Epilobium angustifolium extract demonstrates multiple effects on dermal fibroblasts in vitro and skin photo-protection in vivo.

Stress-induced fibroblast senescence is thought to contribute to skin aging. Ultraviolet light (UV) radiation is the most potent environmental risk factor in these processes. An Epilobium angustifolium (EA) extract was evaluated for its capacity to reverse the senescent response of normal human dermal fibroblasts (NHDF) in vitro and to exhibit skin photo-protection in vivo. The HPLC-UV-MS analysis of the EA preparation identified three major polyphenol groups: tannins (oenothein B), phenolic acids (gallic and chlorogenic acids) and flavonoids. EA extract increased the cell viability of senescent NHDF induced by serum deprivation. It diminished connective tissue growth factor and fibronectin gene expressions in senescent NHDF. Down-regulation of the UV-induced release of both matrix metalloproteinase-1 and -3 and the tissue inhibitor of matrix metalloproteinases-1 and -2, and also down-regulation of the gene expression of hyaluronidase 2 were observed in repeatedly UV-irradiated NHDF after EA extract treatment. Interestingly, EA extract diminished the down-regulation of sirtuin 1 dampened by UV-irradiation. The application of EA extract using a sub-irritating dose protected skin against UV-induced erythema formation in vivo. In summary, EA extract diminished stress-induced effects on NHDF, particularly on connective tissue growth factor, fibronectin and matrix metalloproteinases. These results collectively suggest that EA extract may possess anti-aging properties and that the EA polyphenols might account for these benefits.

Effects of zinc and cadmium ions on cell growth and production of coumarins in cell suspension cultures of Angelica archangelica L.

The plant cell may respond to the excess of heavy metals in its environment by various mechanisms, including enhanced biosynthesis of secondary metabolites. In this study, zinc (0 to 1500 µM) and cadmium ions (0 to 100 µM) were tested as potential elicitors of the production of coumarins in angelica cell suspension cultures. In addition, the toxicity of both metals was assessed by evaluating their effect on cell growth (characterized by fresh and dry biomass at the end of a two-week subculture). It has been found that fresh biomass was not influenced up to zinc concentrations of 150 and 300 µM in the dark-grown and light-grown cultures, resp. Then it declined with an increasing zinc level. Zinc at 1500 µM diminished it by 54% and 24% in the dark-grown and light-grown cultures, resp. Dry biomass was influenced in a similar way. Zinc at 1500 µM reduced dry cell weight by 30% and 20% in cultures in the dark and in the light, resp. Cadmium ions did not affect fresh and dry weights of cells up to concentrations of 10 µM and 50 µM in cultures in the dark and in the light, resp. Toxic concentrations of cadmium are by an order of magnitude lower than those of zinc. Cadmium at 50 µM reduced fresh and dry cell weights by 66% and 59%, resp., in the dark-grown cultures. Cadmium at 100 µM caused a decrease in fresh and dry biomass by 40% and 44%, resp., in the light-grown cultures. Neither zinc nor cadmium improved production of coumarins.

Coated chitosan pellets containing rutin intended for the treatment of inflammatory bowel disease: in vitro characteristics and in vivo evaluation.

Preparation of coated pellets intended for rutin colon delivery, their evaluation in vitro and in vivo in experimental colitis in rats was the purpose of this study. Pellets were obtained using extrusion/spheronization and coated with three types of coatings (caffeic acid/hypromellose/alginic acid; sodium alginate/hypromellose/zinc acetate; sodium alginate/chitosan). Dissolution using buffers of pH values, ß-glucosidase and times corresponding to gastrointestinal tract (GIT) was provided. Pellets coated with alginate/chitosan showed low rutin dissolution (12-14%) in upper GIT conditions and fast release (87-89%) under colon conditions; that is a good presumption of intended rutin release. After colitis induction and development, the rats were treated with pellets and rutin solution administered orally, solution also rectally. Colon/body weight ratio, myeloperoxidase activity and histological evaluation were performed. Rutin was able to promote colonic healing at the dose of 10mg/kg: colon/body weight ratio decreased and myeloperoxidase activity was significantly suppressed. Pellets coated with alginate/chitosan applied orally and rutin solution administered rectally showed the best efficacy. The combination of rutin as natural product, mucoadhesive chitosan degraded in the colon and sodium alginate as the main coating substance in the form of pellets create a promising preparation for therapy of this severe illness.

Determination of selected antioxidants in Melissae herba by isotachophoresis and capillary zone electrophoresis in the column-coupling configuration.

A method utilising isotachophoresis and capillary zone electrophoresis in the column coupling configuration with UV detection at 320 nm was developed for separation and determination of five phenolic acids (rosmarinic, p-coumaric, ferulic, caffeic and chlorogenic) and flavonoid quercitrin in a methanolic extract of Melissae herba. The proposed method has been validated with correlation coefficients from 0.9842 to 0.9988, RSD values between 0.39% and 0.83% for migration times and between 0.40% and 2.05% for peak areas.

Analysis of selected constituents in methanolic extracts of Hypericum perforatum collected in different localities by capillary ITP-CZE.

The on-line combination of CZE with capillary ITP (ITP-CZE) was used for the separation and quantification of selected flavonoids and phenolic acids in Hypericum perforatum leaves and flowers collected in six different localities in Slovakia. The leading electrolyte in the ITP preseparation step was 10 mM HCl with Tris as counterion (pH* 7.2). The terminating electrolyte was 50 mM boric acid of pH* 8.2 (adjusted with barium hydroxide). The BGE in the electrophoretic step contained 25 mM beta-hydroxy-4-morpholinopropanesulfonic acid (MOPSO), 50 mM Tris, 65 mM boric acid, pH* 8.3. The content of methanol in all electrolytes was 20% v/v. The total time of the analysis (including the preseparation step) was approximately 35 min. The rectilinear calibration ranges were between 0.125 and 5.0 microg/mL with kaempferol as internal standard. The correlation coefficients ranged between 0.9912 (for quercitrin and chlorogenic acid) and 0.9988 (for isoquercitrin). The RSD values are between 0.86 and 7.78% (n = 6) when determining rutin and quercetin (4 microg/mL). The optimized method was employed for the assay of flavonoids in medicinal plant extract of different collections of Hypericum perforatum haulm. The variability of the content of the active components depending on the place of collection was confirmed.

Free radical scavenging activity of different extracts and some constituents from the leaves of Ligustrum vulgare and L. delavayanum.

The free radical scavenging activity of the water infusions, different organic solvent extracts and some constituents from Ligustrum vulgare and Ligustrum delavayanum leaves was assessed with the aid of DPPH radical. Among the samples screened, water infusions had the strongest free radical scavenging capacity. From the tested compounds scavenging active flavonoid aglycones are present in the most active chloroform fractions from both leaves samples.