2005 - Fátima Aparecida Vieira Machado
MSc. Thesis
Author: Fátima Aparecida Vieira Machado
Postgraduate Program in Pharmaceutical Sciences -Paulista State University "Júlio de Mesquita Filho"
Area of Knowledge: Research and Development of Drugs and Medicines
Date of Defense: February 25, 2005
Advisor: Prof. Dr. João Carlos Palazzo de Mello
Examination Board: Prof. Dra. Izabel Cristina Piloto Ferreira
Prof. Dra. Hérida Regina Nunes Salgado
Title: Phytochemical Study and Evaluation of the Antioxidant Capacity of Extracts from barks Stryphnodendron polyphyllum Mart., Leguminosae, Barbatimão
Abstract: The genus Stryphnodendron, Leguminosae, grows abundantly in the “cerrado” (central savannahs) of Brazil, where it is populary known as “barbatimão”. The stem barks of Stryphnodendron polyphyllum are extensively used by the local population of treatment of diarrhoea and leukorrhoea, as a blood coagulant, as antiinflamatory and to stimulate wound healing. The isolated chemical groups at the moment are saponins, flavonoids and mainly, tannins. This work aimed at the isolation of polyphenolic compound and the evaluation of the antioxidant capacity from crude extracts and semipurified fractions of the stem bark of S. polyphyllum The ethyl-acetate fraction was submitted to column chromatography, containing Sephadex® LH-20 and was obtained 20 subfractions. From these fractions were isolated and identified five compunds: gallic acid, gallocatechin, epigallocatechin, 4’-O-methylgallocatechin, and fisetinidol-(4α->8)-gallocatechin, through mass spectrometry, 1H NMR, 13C NMR; COSY 1H/H and NOE. The antioxidant capacity was evaluated in vitro, through two spectrophotometric methods: 2,2-diphenyl-1-picrylhidrazyl (DPPH ) radical, and the second based on the reduction of Mo(VI) to Mo(V) with formation of a green phosphate/Mo(V) complex at acidic pH. The result showed for the sample FAE a value of IC50 of 7.602 ± 0.21 (RSD%=2.75) for DPPH radical and the value for relative antioxidant capacity expressed as equivalent of ascorbic acid standard was 0.8178 ± 0.07 (RSD%=4.16) for reduction of phosphomolybdenum complex, among the sample tested.
Dissertation PDF: Fátima Aparecida Vieira Machado
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