Abstract(s)
Nos últimos anos tem crescido o interesse pela descoberta de novos compostos antioxidantes,
a partir de fontes naturais, aplicáveis quer na indústria alimentar como na medicina preventiva.
Neste trabalho foi estudada a capacidade antioxidante de extractos de dez plantas medicinais
Angolanas em diferentes solventes orgânicos (Hymenodictyon floribundum, Parinari pumila,
Tinnea antiscorbutica, Eragrostis viscosa, Xylopia odoratissima, Peucedanum angolense,
Boscia microphylla, Adenodolichos huillensis, Cassia occidentalis e Rhus kirkii). A capacidade
antioxidante foi avaliada por quatro métodos in vitro (ABTS, DPPH, TBA e Valor peróxido). A
concentração de compostos fenólicos totais nos extractos foi determinada pelo método de Folin-
Ciocalteau.
Os compostos fenólicos totais variam entre 40,63mg/g extracto ± 0,00 para a Eragrostis
viscosa em diclorometano e 549,27mg/g extracto ± 0,01 para a Parinari pumila aquoso. A percentagem
mais elevada de inibição de radicais livres de DPPH, quando em comparação com uma
solução de Trolox na mesma concentração dos extractos (69,79 % ± 0,43), foi observada no
extracto de Parinari pumila em metanol com um valor de 36,19 % ± 0,21. Para o método de
ABTS, o valor mais alto de TEAC e de percentagem de inibição, foi observado para o extracto
de Hymenodictyon floribundum em acetato de etilo, respectivamente com o valor de 3,24 mM
Trolox/g extracto ± 0,52 e 5,71 % ± 0,52. No teste de TBA, os extractos de Parinari pumila e
Hymenodictyon floribundum são alguns dos que se mostraram menos eficazes na prevenção da
oxidação do ácido linoleico, embora onze dos extractos tenham apresentado uma capacidade
antioxidante equivalente à do BHA. Relativamente ao valor peróxido, o extracto com melhor
capacidade em diminuir a oxidação ao longo dos oitos dias, foi o de Adenodolichos huillensis
folhas aquoso, com um valor de 37,47meq / g extracto ± 0,20.
Uma vez que a composição química dos diferentes extractos não é conhecida, será necessário
isolar e purificar os diferentes compostos químicos presentes nos extractos.
In recent years there has been growing interest in the discovery of new antioxidant compounds from natural sources, apply whether the food industry and in preventive medicine. In this work the antioxidant capacity of extracts of ten medicinal plants from Angola in different organic solvents (Hymenodictyon floribundum, Parinari pumila, Tinnea antiscorbutica, Eragrostis viscosa, Xylopia odoratissima, Peucedanum angolense, Boscia microphylla, Adenodolichos huillensis, Cassia occidentalis e Rhus kirkii), was studied. The antioxidant capacity was evaluated by four in vitro methods (ABTS, DPPH, TBA and Peroxide value). The concentration of total phenolic compounds in the extracts was determined by Folin-Ciocalteau method. The total phenolic compounds ranging from 40,63 mg / g extract ± 0,00 for Eragrostis viscosa in dichloromethane and 549,27 mg / g extract ± 0,01 for Parinari pumila aqueous. The highest percentage of inhibition of DPPH free radicals, when compared with a solution of Trolox in the same concentration of extracts (69,79 % ± 0,43), was observed in the extract of Parinari pumila in methanol with a value of 36,19 % ± 0,21. For the method of ABTS, the highest value of TEAC and percentage of inhibition was observed for the extract Hymenodictyon floribundum in ethyl acetate, respectively with a value of 3,24 mM Trolox / g extract ± 0,52 and 5,71% ± 0,52. In the test of TBA, the extracts of Parinari pumila and Hymenodictyon floribundum are among those who were less effective in preventing the oxidation of linoleic acid, although eleven of extracts have an antioxidant capacity equivalent to that of BHA. For the peroxide value, the extract with better ability in reduce oxidation during the eight days, was Adenodolichos huillensis leaves aqueous, with a value of 37,47meq / g extract ± 019. Since the chemical composition of different extracts is not known, it is necessary to isolate and purify the different chemical compounds present in the extracts.
In recent years there has been growing interest in the discovery of new antioxidant compounds from natural sources, apply whether the food industry and in preventive medicine. In this work the antioxidant capacity of extracts of ten medicinal plants from Angola in different organic solvents (Hymenodictyon floribundum, Parinari pumila, Tinnea antiscorbutica, Eragrostis viscosa, Xylopia odoratissima, Peucedanum angolense, Boscia microphylla, Adenodolichos huillensis, Cassia occidentalis e Rhus kirkii), was studied. The antioxidant capacity was evaluated by four in vitro methods (ABTS, DPPH, TBA and Peroxide value). The concentration of total phenolic compounds in the extracts was determined by Folin-Ciocalteau method. The total phenolic compounds ranging from 40,63 mg / g extract ± 0,00 for Eragrostis viscosa in dichloromethane and 549,27 mg / g extract ± 0,01 for Parinari pumila aqueous. The highest percentage of inhibition of DPPH free radicals, when compared with a solution of Trolox in the same concentration of extracts (69,79 % ± 0,43), was observed in the extract of Parinari pumila in methanol with a value of 36,19 % ± 0,21. For the method of ABTS, the highest value of TEAC and percentage of inhibition was observed for the extract Hymenodictyon floribundum in ethyl acetate, respectively with a value of 3,24 mM Trolox / g extract ± 0,52 and 5,71% ± 0,52. In the test of TBA, the extracts of Parinari pumila and Hymenodictyon floribundum are among those who were less effective in preventing the oxidation of linoleic acid, although eleven of extracts have an antioxidant capacity equivalent to that of BHA. For the peroxide value, the extract with better ability in reduce oxidation during the eight days, was Adenodolichos huillensis leaves aqueous, with a value of 37,47meq / g extract ± 019. Since the chemical composition of different extracts is not known, it is necessary to isolate and purify the different chemical compounds present in the extracts.
Description
Keywords
Plantas medicinais - Antioxidantes Radicais livres Antioxidantes Antioxidantes - Métodos de avaliação Compostos fenólicos
Citation
Publisher
Universidade da Beira Interior