Data/hora: 03/06/2024 08:35:29

Provedor de dados: 	60	
País: 	Brazil	
Título: 	Antioxidant capacity of extracts and isolated compounds from Stryphnodendron obovatum Benth	
Autores: 	Zocoler,Analice Martins Daleffi; Sanches,Andréia Cristina Conegero; Albrecht,Ingrid; Mello,João Carlos Palazzo de.	
Data: 	2009-09-01	
Ano: 	2009	
Palavras-chave: 	Stryphnodendron obovatum; Antioxidant capacity; Condensed tannins; DPPH free radical; Phosphomolybdenum complex.	
Resumo: 	The extract from stem bark of Stryphnodendron obovatum Benth. was chromatographed on a Sephadex® LH-20 column, and yielded nine compounds: gallic acid (GA), p-hydroxybenzoic acid (PHB), gallocatechin (GC), epigallocatechin (EPG), 4'-O-methylgallocatechin (MGC), epigallocatechin-(4β→8)-epigallocatechin (EPEP), epigallocatechin-(4β→8)-gallocatechin (EPGC), robinetinidol-(4α→8)-gallocatechin (ROGC) and robinetinidol-(4β→8)-epigallocatechin (ROEP). Evaluation of the antioxidant capacity in vitro by the methods of DPPH free radical (IC50; μg/mL) and reduction of the phosphomolybdenum complex (RAC) gave the following results, respectively: crude extract 4.52 and 0.8242; ethyl-acetate fraction 4.04 and 0.9537; aqueous fraction 5.58 and 0.9275. The crude extract and ethyl-acetate fraction were shown to possess an antioxidant capacity comparable to that of vitamin C (4.93 and 1.0). The values obtained by the DPPH free-radical method for the isolated compounds were IC50 (μM): GA=8.89; PHB=10.12; GC=16.46; EPG=13.20; MGC=21.00; EPEP=6.89; EPGC=4.91; ROGC=7.78 and ROEP=6.20. Vitamin C and trolox showed 30.11 and 30.10, respectively. Dimers showed greater activity in scavenging free radicals, possibly related to the number of hydroxyls. However, compounds without a hydroxyl at position 5 of the A-ring (5-deoxy-proanthocyanidins) did not change the antioxidant activity of the DPPH free radical, as evaluated here for the first time. Among the monomers, there appeared to be a direct relationship in scavenging of free radicals because of the stereochemistry of the compounds. The presence of a methyl radical on the B-ring significantly reduced the scavenging of free radicals of gallocatechin. All compounds showed greater scavenging of radicals than vitamin C and trolox, and these two compounds showed no significant difference from each other.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502009000300009	
Editor: 	Universidade de São Paulo, Faculdade de Ciências Farmacêuticas	
Relação: 	10.1590/S1984-82502009000300009	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Pharmaceutical Sciences  v.45 n.3 2009	
Fonte: 	info:eu-repo/semantics/openAccess