Antioxidant and Free-Radical Scavenging Activity of Constituents of the Leaves of Tachigalia paniculata

Abstract

Two new myricetin glycosides, myricetin 7-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (1) and myricetin 7-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (2), together with the known compounds quercetin 3-O-beta-D-glucopyranoside (3), quercetin 3-O-alpha-L-rhamnopyranoside (4), quercetin 3-O-beta-D-galactopyranoside (5), methyl gallate (6), isovanillin (7), 4-hydroxymethylbenzoate (8), 3,4-dihydroxymethylbenzoate (9), and caffeoyl aldehyde (10) were isolated from the leaves of Tachigalia paniculata. The structures of these compounds were determined by spectroscopic methods. Their antioxidant activity was determined by measuring free-radical scavenging effects using three different assays, namely, the Trolox Equivalent Antioxidant Capacity (TEAC) assay, the coupled oxidation of beta-carotene and linoleic acid (autoxidation assay), and the inhibition of xanthine oxidase activity. Compounds 1, 2, and 6 showed activity in the TEAC test, compounds 5-7 and 10 were moderately active in the autoxidation assay, while compounds 1 and 2 were the most potent of the isolates in the xanthine oxidase test.

Flavonoides e atividade antioxidante em Palicourea rigida Kunth, Rubiaceae

“…Vários trabalhos na literatura sugerem a correlação entre as atividades antioxidante e antiinflamatória, ou seja, alguns extratos vegetais reduzem inflamações por eliminar superóxidos conhecidos por participarem do recrutamento de células polimorfonucleares (PMN) presentes em tecidos inflamados (Thambi et al, 2009;Ródenas et al, 2000). Apesar de não ser possível inferir com precisão quais são os compostos responsáveis pela ação antioxidante da fração acetato de etila, os flavonóides devem ser parcialmente responsáveis por esta atividade, tendo em vista os inúmeros trabalhos que relatam as diferentes atividades exibidas por esta classe de compostos, os quais são descritos preponderantemente como potentes antioxidantes (Alves et al, 2007;Furusawa et al, 2005;Suzgeç et al, 2005;Cioffi et al, 2002 …”

Antioxidative Activities of Natural Hydroxy-Bearing Cinnamaldehydes and Cinnamic Acids: A Comparative Study

“…Cinnamaldehydes are more fatsoluble than their corresponding acids, so it is easier for cinnamaldehydes to adhere to the lipid part of erythrocytes than their corresponding acids, and thus cinnamaldehydes showed stronger hemolysis inhibitory activities than their corresponding acids. Certain phenolic compounds may incorporate into the hydrophobic core of the membrane bilayer, causing a reduction in membrane fluidity [17][18][19] [9,11,12,14], such as antimicrobial, anti-inflammatory, and as a good candidate for cancer therapy. Another possible cause for the higher activities of aldehydes is that the carbonyl group of cinnamaldehydes can easily combine with the residual amino group of the protein of RBCs forming reversible imine structure [20].…”

“…Some hydroxybearing cinnamaldehydes, such as ocoumaraldehyde from bark of cinnamon，p-coumaraldehyde， ferulaldehyde，and caffeic aldehyde have been widely studied and found to be good bioactive compounds. Much attention has been paid to their antioxidative activities [8][9][10][11][12][13][14]. But the comparative studies on the antioxidative effects of the hydroxy-bearing cinnamaldehydes with their corresponding acids are few.…”

Phenolic profile of hazelnut (Corylus Avellana L.) leaves cultivars grown in Portugal

“…Antioxidants from plants, namely phenolic compounds [1][2][3], can be used in order to preserve food, for organoleptic and nutritional qualities, and also for medicinal purposes [4,5].…”