Silybum marianum has been a plant known for millenniums thanks to its pharmacological effects especially in fields of liver, gallbladder or even colon cancer treatment. A complex of effective components is called silymarin. Its amount and structure in milk thistle seeds are very important. That{\crq}s why there{\crq}s a tendency to develop methods which could increase silymarin quantity together with silymarin quality in this herb. This was also the aim of this thesis. One of the possibilities to level up the content of effective components in drugs is to bring this plant in stress. There were realized two ground-plot experiments. The stress agens was acetatonsalicylic acid (ASA) of different concentrations applicated on leaves of these plants, concretely in the concentrations of 10-5 mol.l-1, 10-4 mol.l-1, 10-3 mol.l-1. In the case of the application ASA concentration 10-3 mol.l-1 there was proved an effective action. The increase of effective components in seeds reached approximately 116,5 % ratio compared with control application of distilled water on the Silybum marianum leaves. The silymarin complex was determined by High Performance Liquid Chromatography. The preparation of the extract was practised in different ways {--} using ethyl alcohol extract and distilled water in combination with various temperatures of extracts storage. These methods were compared one another. As the best one has been turned out to be using 60% ethanol concentration for the duration of 96 hours in the storage temperature 20°C.

Natural flavonoids and flavonolignans feature beneficial properties for living organisms such as antioxidant and hepatoprotective effects, anticancer, chemoprotective, dermatoprotective and hypocholesterolemic activities. Their metabolism in mammals is complex, the exact structure of their metabolites still remains partly unclear and the standards are usually not commercially available. Hence, this project focused on the preparation of potential and defined biotransformation Phase II sulfated metabolites of silymarin flavonolignans: silybin, 2,3-dehydrosilybin, isosilybin, silychristin, silydianin and flavonoids quercetin, taxifolin, rutin and isoquercitrin. Pure sulfated derivatives were prepared using aryl sulfotransferase from Desulfitobacterium hafniense and aryl sulfotransferase from rat liver. Using heterologously expressed PAPS (3'-phosphoadenosine-5'-phosophosulfate) - independent arylsulfotransferase from Desulfitobacterium hafniense and cheap p-nitrophenyl sulfate as sulfate donor, sulfated flavonolignans and flavonoids were obtained in high yields. Silymarin flavonolignans afforded exclusively monosulfates at the position C-20 (C-19 in the case of silychristin), except 2,3-dehydrosilybin that yielded also the 7,20-O-disulfated derivative. Isoquercitrin and rutin were selectively sulfated...

L'extraction par CO2 supercritique démontre les avantages d'un procédé de chimie verte en comparant ce procédé à la méthode d'extraction par solvant organiques et en tenant compte du degré de toxicité et de pollution du solvant. L'extraction par solvants organiques met en évidence l'influence du solvant d'extraction alors que l'extraction par CO2-SC met en évidence l'influence de différents paramètres dont la pression, la température, le temps de contact entre la matrice végétale et le CO2-SC, le diamètre moyen des particules et l'ajout d'un co-solvant. L'analyse chromatographique a permis d'identifier et de quantifier les flavonolignanes (silychristine, silydianine, silybine, taxifoline) dans les extraits de graines obtenus par solvants organiques et par CO2-SC avec co-solvant. A 220 bar, les concentrations en silydianine (38,87 mg/g) et en silybine (45,91mg/g) sont les plus élevés et à 40°C les concentrations en silychristine (31,97mg/g), en silydianine (38,87 mg/g) et en silybine (45,91mg/g) sont les plus importantes. Les extraits huileux obtenus à 220 bar et à 40°C des graines de Silybum marianum sont riches en acides gras : acide linoléique (65,22%), acide oléique (27,01%), acide palmitique (12,12%). L'activité antioxydante a été évaluée par deux tests : test DPPH et test ABTS. Ces deux tests sont complémentaires et ont permis de conclure que l'extrait ayant un effet antioxydant le plus important est l'extrait obtenu par CO2-SC à 220 bar et à 40°C. L'activité biologique de cet extrait est mise en évidence par rapport à une lignée cellulaire cancéreuse du colon Caco-2. La silychristine, la silydianine et la silybine ainsi que l'extrait obtenu par CO2-SC avec co-solvant (éthanol) à 220 bar et à 40°C ont été testés vis à vis de cette lignée cancéreuse. Ces expérimentations in vitro reflètent une activité cytotoxique quantifiable et une mortalité cellulaire des Caco-2 des flavonolignanes allant jusqu'à 71% / The supercritical CO2 extraction demonstrates the benefits of green chemistry process comparing with the method of organic solvents extraction and depending to toxicity and pollution solvent degree. Organic solvents extraction shows the solvent extraction influence, so that the SC-CO2 extraction highlights different parameters including pressure, temperature, contact time between the plant matrix and CO2 SC, the average particle diameter and the addition of a cosolvent. Chromatographic analysis identified and quantified four flavonolignans (silychristin, silydianin, silybin, taxifolin) in seed extracts obtained by organic solvents and SC-CO2 with cosolvent. At 220 bar, silydianin (38.87 mg / g) and silybin (45.91 mg / g) have highest concentrations and at 40°C silychristin (31.97 mg / g), silydianin (38.87 mg / g) and silybin (45.91 mg / g) have the most important concentrations. The oily extracts obtained at 220 bar and 40°C of Silybum marianum seeds are rich in fatty acids: linoleic acid (65.22%), oleic acid (27.01%), palmitic acid (12.12%). The antioxidant activity measured by two tests: DPPH and ABTS test. These two tests are complementary and confirm that the extract with the higher antioxidant effect is the extract obtained by SC-CO2 at 220 bar and 40°C. The biological activity of this extract is demonstrated with respect to a colon cancer cell line Caco-2. Silychristin, silydianin and silybin and the extract obtained by CO2-SC with co-solvent (ethanol) at 220 bar and 40°C were tested with respect to this line cancer. These experiments in vitro cytotoxic activity reflect estimable and cell death of Caco-2 flavonolignans of up to 71%