Analisi comparativa dell'attività antiossidante fra estratti con CO2 supercritica e tinture alcoliche vegetali

This work aims to provide a comparison of antioxidant activity between supercritical carbon dioxide plant extract (SFE ) and alcoholic maceration (Tincture). The scope is to evaluate whether extraction by supercritical CO2, can be considered a convenient technique for the extraction of antioxidant compounds. The first part of this work was dedicated to the extraction of nine plants, used in traditional medicine and not: Echinacea angustifolia, Poygonum cuspidatum, Rosa canina, Sylibum marianum, Solanum lycopersicum, Eschscholtzia californica, Uncaria tomentosa, Passiflora incarnate and Vitis vinifera. Afterwards, the extracts obtained were compared with their respective tinctures to evaluate the antioxidant activity. Two assays, ABTS and DPPH, were used because they react differently according to the structure of the antioxidant compounds. Combining the data on the extraction parameters and antioxidants results, it was possible to hypothesize the behavior of compounds when extracted with the two techniques. The data strongly demonstrate the crucial role of extraction parameters to obtain selectively the bioactive compounds by Supercrtitical CO2. Although the ethanol maceration has been proved, often, more efficient in the extraction of antioxidant compounds, it is necessary to highlight for plant matrix rich in lipophilic antioxidant compounds such as S. lycopersicum, the optimal SFE parameters allow to obtain a very powerful bioactive extract. In conclusion, my results supported the literature data that showed that SC-CO2 is a versatile and powerful extraction technique based on green technologies. SC-CO2 allow the extraction of a wide range of secondary metabolites from different plant tissues and species. However, appropriate set up of extraction parameters and scale up make this technology less ready to use. Moreover, the main reason of the limited diffusion of SFE technology is the huge cost of industrial plan. Only molecules of plant extract with an high economic value on the market can justify the use SC-CO2 instead of traditional low costly extraction techniques.