Dihydrochalcones: Implication in resistance to oxidative stress and bioactivities against advanced glycation end-products and vasoconstriction

Abstract

Flavonoids are a group of polyphenol compounds with known antioxidant activities. Among them, dihydrochalcones are mainly found in apple leaves (Malus domestica). Glycosylated dihydrochalcones were previously found in large amounts in leaves of two genotypes of Malus with contrasting resistance to fire blight, a bacterial disease caused by Erwinia amylovora. In the present study we demonstrate that soluble polyphenol patterns comprised phloridzin alone or in combination with two additional dihydrochalcones, identified as sieboldin and trilobatin. Presence of sieboldin in young leaves correlated well with a high 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. Moreover, these leaves displayed enhanced tolerance to paraquat, a photooxidative-stress generating herbicide. Interestingly, phloridzin had a high activity in the oxygen radical absorbance capacity (ORAC) assay, but its presence alone in leaves did not correlate with tolerance to paraquat. In order to further characterise the activity of these compounds, we tested their ability to prevent oxidative-dependent formation of advanced glycation end-products (AGEs) and phenylephrine-induced contraction of isolated rat mesenteric arteries. The antioxidant capacity of sieboldin was clearly demonstrated by showing that this compound (i) prevented vasoconstriction and (ii) inhibited AGEs formation. Both assays provided interesting information concerning a potential use of sieboldin as a therapeutic. Hence, our results strongly argue for a bioactivity of dihydrochalcones as functional antioxidants in the resistance of Malus leaves to oxidative stress. In addition, we demonstrate for the first time that sieboldin is a powerful multipotent antioxidant, effective in preventing physiopathological processes. Further work should aim at demonstrating the potential use of this compound as a therapeutic in treating free radical-involving diseases.

Flavonoides e outras substâncias de Lippia sidoides e suas atividades antioxidantes

“…8 Do extrato etanólico das raízes foi isolada e identificada a naftoquinona tecomaquinona (1), 5 e do extrato etanólico das folhas foram isolados e identificados o monoterpeno carvacrol, 9 o flavonoide naringenina (4',5,7-tri-hidroxiflavanona, 2), 10 a mistura de 3',4',5,7-tetra-hidroxiflavanona (3) 11 e 4',5,7-tri-hidroxi-6-metoxiflavona (4) 11 e a mistura de 2'-O-glicopiranosil-3,4,4',6'-tetra-hidroxi-di-hidrochalcona (5) 12 e 2'-O-glicopiranosil-4,4',6'-tri-hidroxi-di-hidrochalcona (6) 13 , resumidos na Tabela 1, foram usados para deduzir as estruturas dos componentes da mistura como 2'-O-b-D-glicopiranosil-3,4,4',6'-tetra-hidroxi-di-hidrochalcona (5) e 2'-O-b-D-glicopiranosil-4,4',6'-tri-hidroxi-di-hidrochalcona (6). Os dados da Tabela 1 permitiram também estabelecer a correlação inequívoca dos deslocamentos dos átomos de hidrogênio e carbono das duas di-hidrochalconas (5 e 6).…”

Plant-Derived Agents with Anti-Glycation Activity

“…The anti-glycation capacity of numerous medicinal herbs and dietary plants was comparable with [59], or even stronger than that of aminoguanidine [42,60,[61][62][63]. Several studies have demonstrated that the anti-glycation activity correlates significantly with the phenolic content of the tested plant extracts [5,50,59,64,65].…”

“…Among the known dihydrochalcones, phloridzin and its aglycone, phloretin, are simple forms [91] and their biosynthesis in Malus has been recently described [92]. Bernonville et al (2010), demonstrated the presence of phloridzin alone or in combination with two additional dihydrochalcones, identified as sieboldin and trilobatin [60]. Phloridzin was shown to inhibit glucose intestinal absorption and renal resorption, resulting in normalization of blood glucose and overall diminution of glycaemia in animal models [93].…”

“…Phloridzin was shown to inhibit glucose intestinal absorption and renal resorption, resulting in normalization of blood glucose and overall diminution of glycaemia in animal models [93]. Based on the results of the antioxidant assays and the fact that sieboldin was several folds more efficient than phloridzin in inhibiting AGE formation (10-fold lower IC50 than phloridzin and 40-fold lower IC50 (0.2 mM) than AG), a role for sieboldin in inhibiting the formation of intermediate glycation products is suggestive [60].…”

Determination of phytochemical composition and antioxidant capacity of 22 old apple cultivars grown in Poland

“…It is a phytoalexin that provides resistance to the pathogens-Venturia inaequalis and Erwinia amylovora [13,14]. Phloridzin can inhibit lipid peroxidation [15,16].…”