Structure-activity relationships regarding the antioxidant effects of the flavonoids on human erythrocytes

Abstract

The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H<sub>2</sub>O<sub>2</sub> for 60 min at 37 ºC have been studied. The following flavonoids; quercetin, rutin and morin significantly protected eryt-hrocytes against lipid peroxidation caused by H<sub>2</sub>O<sub>2</sub>. This inhibition of lipid peroxidation could be explained by the presence of at least two hydroxyl groups in ring B of the flavonoid structure, regardless of their positions. However, the flavonoids; quercetin, 3,5,7-trihy- droxy-4'-methoxy flavone-7-rutinoside and 3- hydroxy flavone significantly protected eryt-hrocytes against protein degradation. This inhibition could also be explained by the presence of a hydroxyl group at C-3 in ring C of the flavonoid structure. Quercetin and 3,5,7-trihydroxy-4'- methoxy flvone-7-rutinoside significantly protected erythrocytes against loss of deformability and increased osmotic fragility, indicating that the loss of erythrocyte deformability and the increase in osmotic fragility of erythrocytes exposed to H<sub>2</sub>O<sub>2</sub> are related to protein degradation rather than to lipid peroxidation. The other flavonoids (chrysin, 2-carboxy ethyl dihydroxy flavone, apigenin, cirsimaritin, α-naphto flavone and flavanone) failed to protect erythrocytes against the observed oxidative damages. The results demonstrate the importance of the chemical groups substituted on the basic skeleton of the flavonoids in dictating the type of antioxidant activity, and also demonstrate the hemorheological potentials of flavonoids that have particular protein-antioxidant activities

A review of the factors that influence erythrocyte osmotic fragility

“…and Solidago microglossa increased erythrocyte osmotic fragility in humans (de Freistas et al, 2008). Biltto et al (2012) reported that preincubation of erythrocytes with rutin and α-naphtho flavone did not have any effect on osmotic fragility but quercetin and 3, 5, 7-tri-hydroxy-4'-methoxy flavone-7-rutinoside reduced osmotic fragility of human erythrocytes. Oral administration of ethanol extracts of Jatropha gossypifolia (Pohl) (Oyedeji et al, 2015a) and Adenopus breviflorus (Benth) (Oyedeji et al, 2015b) did not affect erythrocyte osmotic fragility in male Wistar rats.…”

Reactivity of phenolic compounds towards free radicals under in vitro conditions

“…The structure-antioxidant activity relationship (SAR) approach is considered to be useful for food, cosmetic and pharmaceutical applications as it provides evidence about the potency of natural phenolic constituents (Bountagkidou et al 2010). Bilto et al (2012), Sivakumar et al (2011), Bountagkidou et al (2010), Natella et al (1999) and Torres de Pinedo et al (2007) studied the SAR of flavonoids, chalcone derivatives, hydroxybenzaldehydes, benzoic and cinnamic acids and phenolic based antioxidants respectively employing different antioxidant assay methods. Cai et al (2006) studied the SAR of phenolic antioxidants from Chinese medicinal plants using ABTS and DPPH radical scavenging assays.…”

In Silico Study and Bioprospection of the Antibacterial and Antioxidant Effects of Flavone and Its Hydroxylated Derivatives

“…The experiment was carried out in accordance with a study by Bilton et al [ 59 ], with minor modifications. Each flavonoid (1, 10, 100, 200 and 500 μg/mL) was incubated with 2 mL of a 0.5% erythrocyte suspension in 0.9% NaCl for 4 h at 25 ± 2 °C in the presence of H 2 O 2 (40 mM).…”