Extração, saponificação e atividade antioxidante de luteína obtida de flores Tagetes patula L. e Calendula officinalis L.

• Autor(a) principal: Nachtigall, Aline Manke
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/471
• topic: Luteína; Saponificação; Extração; Atividade antioxidante; Flores; Lutein; Saponification; Extraction; Antioxidant activity; Flowers; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS

The aim of this present study was to evaluate the availability of using Tagetes patula L. (african marigold) and Calendula officinalis L. (marigold) flowers as sources of the lutein, as well as to evaluate the effect of the saponification process and extraction solvents over the oilresins and its antioxidant powers. The characterization of the flowers yellow, orange and brown T. patula L. flowers, as well as the yellow and orange C. officinalis L. was determined by their UV-visible spectra and high-Performance Liquid Chromatography (HPLC). The extract is obtained from a 24-hour extraction with tetrahydrofurane and saponification overnight with a solution of 10% KOH in ethanol. The highest content of lutein (means) was verified in the brown african marigold (1230,6 mg.100g-1), which was significantly higher than the values encountered in the yellow and orange marigold (29,80 mg.100g-1). However, these content values had not differed from the yellow african marigold (59,7 mg.100g-1). The brown african marigold and the orange marigold were the selected flowers to be carried out in the succeeding experiments since those were the ones showing the highest contents of lutein in each species. The influences of the modifications in the saponification process and extraction solvents over the contents of lutein and the carotenoid profiles of the extracts of the flowers were evaluated by UV-visible spectra and HPLC. The extracts of the lutein of the brown african marigold and the orange marigold flowers were obtained through a cold extraction of the dried petals for 24 hours, with the solvents ethanol, tetrahydrofurane, hexane and, hot extraction with hexane was also conducted by using a soxhlet apparatus in which a dynamic extraction took place for 7 hours, followed by an overnight static extraction and an extra hour of a dynamic extraction. Half of the extracts were not submitted to saponification whereas the other half was saponified, simultaneously to the ex traction, with a 10% KOH in ethanol (w/v), in a ratio of 1:1. The effect of the saponification on the profile chromatographic of the extracts was just verified in the flowers of african marigold, where a clear increase was observed in the lutein proportion accompanied by the reduction of the other carotenoids. However, when extracts of orange C. Officinalis L. were submitted to saponification, an increase in the lutein content was not observed whereas contents of other carotenoids actually increased. Hence, whenever working with african marigold, it is necessary to submit these flowers to saponification whereas marigold do not demand it. As far as the extraction solvent goes, it was confirmed that each one had different performances over the studied lutein sources. The marigold didn't suffer influence of the solvents, and for the african marigold the best solvents extractors were the tetraidrofurano (1220,0 mg.100g-1) and the hexano (893,9 mg.100g-1). Not only the use of temperature caused degradation of pigments but it also provided less pure extracts. The effects of the solvent extractor and of the saponification about the antioxidant capacity of the extracts were appraised for the test of the free radical DPPH and of the β-caroten/ac. linoleic. The saponification was associated with reducing the protection capacity of the extracts due to the oxidation effects. This capacity was not only correlated to the lutein contents, but to the influence of other antioxidants compounds as well. The extracts that presented larger capacity of reduction of the radical DPPH were the one of extracted marigold with independent tetrahydrofurane of the saponification and the one of extracted african marigold with ethanol without saponification and the extracted saponificado with tetrahydrofurane (0,004; 0,015; 0,044 and 0,068 g.mmol of DPPH-1, respectively). Saponification had no affect on the results of these former extracts. The african marigold extracts and more effective marigold about the inhibition of the peroxidation lipidic were the not saponification extracted with tetrahydrofurane (72,22% and 72,97%, respectively). It can be noticed that the plant sources analyzed in this study have their extracts highly influenced not only by the solvents and temperature but to saponification processes as well. The saponification estimulates an increase of the lutein concentration in the extracts. However, since lutein is not the only existent antioxidant substance in the extracts, the conduction of saponification processes tend to reduce the of protective antioxidant ability they possess. The results of this study indicate that the analised flowers are promising sources of biological active compounds, such as lutein, which contain antioxidants properties that assist in the strengthening of the imunologic system as well as reduce the risks of developing degenerative deseases.