MEDICINE AND PHARMACY

. Natural antioxidants protect cells against oxidative stress, which is directly involved in ageing processes and in the pathogenesis of cardiovascular, neurodegenerative and neoplastic diseases. Taraxacum officinale (TO) due to its rich content of biologically active ingredients has been commonly used in traditional medicine. It contains a wide spectrum of compounds with antioxidant activity. The content depends of parts of this plant. The roots are rich in phenolic and terpene compounds, sesquiterpene lactones, fructosans and inulin, while leaves are rich in substances belonging to flavonoids, phenolic acids, coumarins and vitamins, especially vitamin A. The literature results prove that antioxidant activity of TO depends on several factors including the plant part, the solvent used, as well as the duration of extraction. The aim of this study was to evaluate and to compare the action of alcoholic extracts of roots and leaves of TO on RBC’s catalase activity. Material and methods. Raw Taraxacum officinale plant material consisted of dried leaves and roots were harvested from a natural site. The extracts for analysis were prepared using 20, 25, 40, 50 and 80% (v/v) ethanol mixtures used as solvents. The catalase activity was established by using RBC of healthy persons. Conclusions. Phytotherapeutic herbs and plants continue to play an important role in the discovery and development of drugs. Leaves and roots of dandelion represent a rich source of bioactive compounds for potential exploitation in nutraceuticals and pharmacological sectors. Taraxacum officinale has a high ability to act as an antioxidant. The highest influence on RBC’s catalase activity was reported in case of roots ethanolic extracts of 25%. These actions are realized due to multiple substances, whose content probably depends of ethanol’s concentration. Additional studies are needed to characterize biological activities of these extracts.

peroxisomes. This enzyme represents a tetramer of four polypeptide chains, with four iron-containing heme groups that allow the enzyme to react with the hydrogen peroxide. By means of a peroxidation reaction the catalase can eliminates the poisonous hydrogen peroxide in the process of oxidizing other substances, including alcohols, phenols, formic acid and formaldehyde. The optimal pH for catalase activity is about 7 and the rate of reaction does not change too much between 6,8 and 7,5.
People always tried to find in the nature components that can solve cruel health problems. The evaluation of the antioxidant activity of plants has been an important issue taking into account its importance on human health. Taraxacum officinale (TO), popularly known as dandelion, demonstrated its effectiveness in treatment of liver disorders, inflammations, as well as exhibited promising antibacterial, antiviral, antiparasitic, antifungal and cytotoxic activities.
Taraxacum officinale is an excellent source of terpene derivatives (taraxerol, taraxasterol and the glycoside taraxacoside), as well as sterols (ß-sitosterol, stigmasterol), rubber, tannins, fatty acids, levulose, caffeic acid, ϸhydroxyphenylacetic acid, asparagine, tyrosine, carotenoids, phytosterol, ß-amirin, flavonoids, citric acid, amino acids, saponins and inulin. This plant is also rich in minerals such as iron, copper, potassium, contains a lot of vitamins A, C B1, PP and D. Extracts from TO exhibit a significant antioxidant activity, which seems to be THEORY AND PRACTICE OF SCIENCE: KEY ASPECTS 170 related to the presence of phenolic compounds. However, in plasma, the best protective effect against H 2 O 2 / Fe oxidation was reported in the presence of enriched fractions of SL amino acid adducts (flavonoids, sesquiterpene lactones) and inositol 4-hydroxyphenylacetate esters. Because TO contain many components, it is difficult to assimilate their mechanisms of action, since these are generally ill-understood.
Nowadays, there is no exhaustive data which can describe the TO content and action regarding to different types of extractants and their concentration, as well to compare roots and leaves action on catalase activity.
Aim of the study. To explore the impact of different Taraxacum officinale ethanolic extracts with different bioactive ingredients on red blood cells (RBC) catalase activity.

Materials and methods. Leaves and roots of Taraxacum officinale F. H. Wigg
were harvested from a natural habitat (May 2017). Two weeks of desiccation took place in the lab conditions, at room temperature. Dried leaves and roots were ground manually to a fine powder and five series (20, 25, 40, 50 and 80%) of ethanolic extracts were made. The ratio of biomass-to-solvent was 10:1(expressed in mg/ml).
The extraction of active components was done in recipients of 100 ml during 24 hours, at room temperature. The extracts were filtered (Whatman No.1) and stored at +4 0 C. Extracts' aliquots (1.5ml) were centrifuged (MPW 370, 5 min, 5000 rpm) and supernatants were used for further assays.
The RBC's catalase was obtained in accordance with method purposed by Results. The catalase activity was different in diverse ethanolic extracts of TO.
In case of roots extracts of 20%, catalase was measured as 48,04±0,73 (p=0,05), data which were lower with 13,3% than control. This enzyme activity grew up By comparing the results, leaves vs roots have been established: catalase activity in leaves extracts, made with ethanol of 20% is lower than roots made with the same extractant with 24,3% (p=0,05), leaves extracted with 25% ethanol exhibited a lower activity than roots with 8,5% (p=0,05), equal in ethanol's of 40% (1,3%, p=0,51), 50% (1,8%, p=0,51) and 80% (2,1%, p=0,28). These results were plotted in Fig.1. The investigation, identification and quantification of the bioactive compounds of TO extracts are related mainly to phenolic compounds, which play an important role in plants defense reactions against biotic and abiotic stresses, as well as in nutrition and welfare. But TO contains a wide spectrum of bioactive components whose ratio and summary effects on different biochemical processes will be debated by many experiments.
The type of extractant seems to be very important. In accordance to Hu et al.  (12). Their results showed that TO leaves extract blocks the growth of MCF-7/AZ cancerous cells, while flowers and roots extracts had no effect on cells growth, but roots extracts in turn were able to block tumor invasion. Esatbeyoglu et al. (2017) supplemented the TO heterogenic activity by demonstrating that leaves extracts activate the transcription of nuclear related factor 2 in human hepatocytes more than roots extracts (13).
Such kind of data generates assumption that content and ratio of bioactive components, as well the action in case of oxidative stress in our experiment should be different. And it was proved. In our experiment, the catalase activity was influenced also by ethanol concentration, in both cases, roots and leaves. We reported before that other biochemical pathways of oxidative stress are influenced by TO in ethanol concentration dependent manner (14)(15)(16).
Commission monographs recommended the use of TO three times daily as herb or liquid extract 1:1 in 25% alcohol, which corresponds in fact with our results, where highest activity of catalase was determined exactly in this ethanol's concentration (6).
Taraxacum officinale is not a single example which describes how important is the type of solvent, the literature abounds in fresh data which underlines the importance of extractant type and its concentration (17)(18)(19).
Conclusions. Phytotherapeutic herbs and plants continue to play an important role in the discovery and development of drugs. Leaves and roots of dandelion represent a rich source of bioactive compounds for potential exploitation in nutraceuticals and pharmacological sectors. Taraxacum officinale has a high ability to act as an antioxidant. The highest influence on RBC's catalase activity was reported in case of roots ethanolic extracts of 25%. These actions are realized due to multiple substances, whose content probably depends of ethanol's concentration.
Additional studies are needed to characterize biological activities of these extracts.