Extratos secos padronizados de Bidens pilosa L.: Desenvolvimento tecnológico e avaliação da atividade biológica

Abstract

Cortes Rojas, D.F. Standarized dried extracts of Bidens pilosa L.: Technological development and evaluation of biological activity. 2011. 165 f. Dissertation (Master). Faculdade de Ciencias Farmaceuticas de Ribeirao Preto – Universidade de Sao Paulo, Ribeirao Preto, 2011. This work presents the development of an experimental methodology in order to produce a standardized dried extract of Bidens pilosa L. This plant is commonly known as picao-preto and is used in traditional medicine due to its biological activities as antimalaric, antioxidant, antimicrobial, hepatoprotector and for jaundice treatment. The first stage of this work was the characterization of the plant material, regarding to pharmacognostic profile, particle size, drying loss, total flavonoids and polyphenol content. Different populations of B. pilosa were collected from different places and the plants were divided in roots, steams and leaves-flowers. Extracts were analyzed comparatively with respect to flavonoid and polyphenol content and antioxidant activity. Based on the results was selected the plant material that presented the higher content of compounds analyzed which were associated to the antioxidant activity. It was also determined that the leaves-flowers were the plant part that presented the higher antioxidant activity, flavonoid and polyphenols content. Once selected the plant material, an experimental design associated to response surface was employed in order to analyze the temperature and ethanol concentration influence on the extraction process of antioxidants. Antifungal activity of the extracts was determined presenting and inverse relationship with antioxidant activity. Optimum conditions were selected based on the results of the experimental design and a comparative study with others extractions methods. The selected solution was employed in the drying process stage. Initially, preliminary studies were performed by spray drying and spouted bed drying testing different drying carriers, freeze dried extract was set as reference. Dried extracts were characterized in flavonoid content, particle size, solubility, water content and the flowing properties. Compounds previously isolated from this plant and reported in the literature were set as markers and their degradation were monitored by high performance liquid chromatography (HPLC). Drying efficiency was also assessed by product recovery, elutriation and accumulation. These experiments allowed to select a blend of Aerosil and microcrystalline cellulose as the best drying carrier and were tested in different operational conditions using an experimental design. Extracts from those planed experiments were characterized by its physics and chemical properties in order to define the optimum drying conditions. Results showed lower compounds degradation by spray drying and a better drying efficiency. Finally antifungal activity of a freeze dried water infusion was higher than the antifungal activity of spray and spouted bed dried extracts obtained at the optimized conditions for antioxidant extraction.