Avaliação da atividade alelopática, antioxidante, fotoprotetora e do perfil fitoquímico de extratos de folhas de Geonoma schottiana (Arecaceae)

• Ano de defesa: 2020
• Autor(a) principal: Gomes, Alessandro Bermudes
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Doutorado em Biologia Vegetal; Centro de Ciências Humanas e Naturais; UFES; Programa de Pós-Graduação em Biologia Vegetal
• Palavras-chave em Português: Alelopatia; bioprospecção; germinação; antioxidantes; subject.br-rjbn; Agronomia
• Link de acesso: http://repositorio.ufes.br/handle/10/14841

Geonoma schottiana Mart. is a native plant of the Atlantic Forest and it shows few studies on its biological and phytochemical potential. Therefore, this study aimed at bioprospecting of the G. schottiana leaves, evaluating its allelopathic, antioxidant, photoprotective potential and the phytochemical constitution of the ethanolic extract and its fractions (hexane, dichloromethane, ethyl acetate and butanol). The allelopathic activity was developed through biological tests with analysis of the germination variables and the initial growth, in which the hexane and butanol fractions showed the best results, as they potentiated the germination and growth variables on the lettuce and sensitized the colonio grass. The analysis of the hexane and butanol fractions at a concentration of 1.0 mg / mL promoted an increase in the activity of the antioxidant enzymes Catalase (CAT), Peroxidase (POX) and superoxide dismutase (SOD)as well as lipid peroxidation (MDA) on seed and roots of colonio grass. The contents of phenolic compounds and total flavonoids were evaluated by the Folin-Ciocalteau and aluminum chloride methods, respectively, while the tannins were determined by the casein precipitation method. The antioxidant activity was determined by ABTS, DPPH, FRAP, TAC-Phosphomolybdenum assay. The analysis of ABTS redox activity increased in the butanol fraction, as well as in the DPPH in the ethyl acetate and dichloromethane fractions and in the FRAP for the dichloromethane fraction, compared to the trolox equivalent (µMol Trolox / g of the extract). The TAC-Phosphomolybdenum assay was significant for the hexane and dichloromethane fractions compared to ascorbic acid equivalents (µg EAA g-1). Phytochemical prospecting was performed by thin layer chromatography (CCD), high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (CG/EM). steroids, lignin, mono and diterpenes, alkali and flavonoids were identified in phytochemical prospecting by CCD for the hexane and butanol fractions. The HPLC analysis demonstrated the presence of chlorogenic acid in the crude extract and hyperoside in the ethyl acetate fraction, with the patterns isoquecertine, mirecithin and rutin found in the ethyl acetate and butanol fraction. The CG/EM of the hexane and dichloromethane fractions demonstrated the presence of phytol, a precursor to vitamin E. The photoprotection factor of the ethanolic extract and its fractions was evaluated, and the hexane fraction obtained the best result for the sun protection factor (6.39). In summary, the results obtained in this work indicate that the ethanol extract from G. schottiana leaves and its fractions have potential as a source of compounds with allelopathic, antioxidant and photoprotective activities.