| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 2.5 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
As flores de várias espécies dos géneros Cytisus e Genista (da Tribo Genisteae, família Fabaceae) são muito utilizadas em todo o Mediterrâneo, e em particular na região do Nordeste de Portugal, para fins medicinais e condimentares. Tradicionalmente procede-se à secagem destas flores logo após a colheita, mantendo-as à sombra e à temperatura ambiente durante um período de cerca de 30 dias. No entanto, o processo de liofilização tem vindo a ser indicado como uma melhor alternativa para a preservação da qualidade das amostras de material vegetal. Neste trabalho, avaliaram-se os efeitos do processo de secagem (tradicional versus liofilização) no potencial antioxidante e na composição fitoquímica de flores de Cytisus multiflorus (L'Hér.) Sweet (giesta branca), Cytisus scoparius (L.) Link (giesta negral), Cytisus striatus (Hill) Rothm. (giesta amarela) e Pterospartum tridentatum (L.) Willk (carqueja).
As propriedades antioxidantes foram avaliadas por métodos bioquímicos (inibição da descoloração do β-caroteno na presença de radicais livres derivados do ácido linoleico e inibição da formação de espécies reativas do ácido tiobarbitúrico (TBARS) em homogeneizados cerebrais) e métodos químicos (determinação do poder redutor e da capacidade captadora de radicais 2,2-difenil-1-picril-hidrazilo (DPPH)). Determinaram-se antioxidantes hidrofílicos (ácido ascórbico, fenóis incluindo flavonóis e ésteres tartáricos e açúcares) e lipofílicos (carotenoides incluindo β-caroteno e licopeno, clorofilas, tocoferóis e ácidos gordos). O valor energético das amostras também foi calculado com base nos níveis totais de lípidos, proteínas e glúcidos.
A amostra liofilizada de Pterospartum tridentatum apresentou a maior atividade antioxidante (valores de EC50 0,15 mg/mL), o que está de acordo com os seus níveis mais elevados de fenóis (~520 mg EACl/g extrato). As amostras liofilizadas demonstraram sempre maior bioatividade e maiores concentrações de antioxidantes hidrofílicos (fenóis, ácido ascórbico e açúcares) e lipofílicos (tocoferóis, clorofilas e licopeno). No entanto, o processo de secagem não teve influência significativa na contribuição energética (que variou entre 386 e 404 kcal/100 g de massa seca).
Os resultados obtidos dão suporte técnico e científico aos usos tradicionais destas plantas na medicina popular como anti-inflamatórios, destacando-as como fonte de compostos bioativos. Mais ainda, a liofilização mostrou preservar de uma forma mais eficaz as qualidades das plantas medicinais em estudo, podendo ser aplicada a plantas medicinais para utilizações na indústria cosmética ou farmacêutica.
Flowers from several common Mediterranean shrubs, such as those from the Cytisus genus and Genista genus (tribe Genisteae/Fabaceae) have long been used for medicinal purposes and seasoning in the northeastern Portuguese region. Despite, the shade-drying traditionally used to process these plants, freeze-drying is claimed to better preserve the quality of medicinal plants. Herein, the effects of drying process in the antioxidants composition and properties of Cytisus multiflorus (L'Hér.) Sweet (white Spanish broom), Cytisus scoparius (L.) Link (common broom), Cytisus striatus (Hill) Rothm. (Portuguese broom) and Pterospartum tridentatum (L.) Willk were evaluated. The antioxidant activity was evaluated by biochemical (β-carotene bleaching inhibition in the presence of free radicals derived from linoleic acid and inhibition of lipid peroxidation though thiobarbituric acid reactive substances (TBARS) assay) and chemical methods (2,2-diphenyl-1-pycrilhydrazil (DPPH) radical scavenging capacity and reducing power). Hydrophilic (ascorbic acid, sugars and phenolics including flavonols and tartaric esters) and lipophilic (carotenoids including β-carotene and lycopene, chlorophylls, tocopherols, and fatty acids) compounds were quantified. The energetic value of the samples was also calculated based on the total levels of fats, proteins and carbohydrates. Pterospartum tridentatum submitted to freeze- or shade-drying proved to be the species with highest antioxidant capacity in all the assayed methods (lowest EC50 values), which is in agreement to its highest levels of phenolics (~500 mg ClAE/g extract). Freeze-drying benefits were confirmed showing, the samples submitted to this process, higher antioxidant activity and higher concentrations of hydrophilic (phenolics, ascorbic acid and sugars) and lipophilic (tocopherols, chlorophylls and lycopene) compounds. Nevertheless, the drying process did not have significantly influence in energetic contribution (values ranging from 386 and 404 kcal/100 g dry weight). The results give technical and scientific support to the traditional uses of these plants in folk medicine as anti-inflammatory, highlighting them as a source of bioactive compounds. Moreover, the drying process to be used in industrial applications is very important, since freeze-drying proved to preserve more the quality of the studied medicinal plants. This process could be applied in scale-up treatments of the studied plants for cosmetic or pharmaceutical applications.
Flowers from several common Mediterranean shrubs, such as those from the Cytisus genus and Genista genus (tribe Genisteae/Fabaceae) have long been used for medicinal purposes and seasoning in the northeastern Portuguese region. Despite, the shade-drying traditionally used to process these plants, freeze-drying is claimed to better preserve the quality of medicinal plants. Herein, the effects of drying process in the antioxidants composition and properties of Cytisus multiflorus (L'Hér.) Sweet (white Spanish broom), Cytisus scoparius (L.) Link (common broom), Cytisus striatus (Hill) Rothm. (Portuguese broom) and Pterospartum tridentatum (L.) Willk were evaluated. The antioxidant activity was evaluated by biochemical (β-carotene bleaching inhibition in the presence of free radicals derived from linoleic acid and inhibition of lipid peroxidation though thiobarbituric acid reactive substances (TBARS) assay) and chemical methods (2,2-diphenyl-1-pycrilhydrazil (DPPH) radical scavenging capacity and reducing power). Hydrophilic (ascorbic acid, sugars and phenolics including flavonols and tartaric esters) and lipophilic (carotenoids including β-carotene and lycopene, chlorophylls, tocopherols, and fatty acids) compounds were quantified. The energetic value of the samples was also calculated based on the total levels of fats, proteins and carbohydrates. Pterospartum tridentatum submitted to freeze- or shade-drying proved to be the species with highest antioxidant capacity in all the assayed methods (lowest EC50 values), which is in agreement to its highest levels of phenolics (~500 mg ClAE/g extract). Freeze-drying benefits were confirmed showing, the samples submitted to this process, higher antioxidant activity and higher concentrations of hydrophilic (phenolics, ascorbic acid and sugars) and lipophilic (tocopherols, chlorophylls and lycopene) compounds. Nevertheless, the drying process did not have significantly influence in energetic contribution (values ranging from 386 and 404 kcal/100 g dry weight). The results give technical and scientific support to the traditional uses of these plants in folk medicine as anti-inflammatory, highlighting them as a source of bioactive compounds. Moreover, the drying process to be used in industrial applications is very important, since freeze-drying proved to preserve more the quality of the studied medicinal plants. This process could be applied in scale-up treatments of the studied plants for cosmetic or pharmaceutical applications.
Description
Keywords
Citation
Pinela, José Virgílio Santulhão (2012). Efeito do processo de secagem no potencial antioxidante e na composição fitoquímica de plantas medicinais da família Fabaceae. Bragança: Escola Superior Agrária. Dissertação de Mestrado em Biotecnologia
Publisher
Instituto Politécnico de Bragança, Escola Superior Agrária