RESUMO
Polyphenol-rich diet decreases cardiovascular risk. LDL oxidation is the primary event in atherosclerosis plaque formation and antioxidants such as polyphenols were shown to inhibit LDL oxidation and atherosclerosis development. Hawthorn (Crataegus) and derived pharmaceuticals are rich in polyphenols and already prescribed to treat moderate heart failure, nervousness and sleep disorders. Extracts either from fresh plant parts (flower buds, flowers, young leaves or green fruits) or from dried pharmaceutical parts (flowers and flowering tops) were previously shown to be effective inhibitors of lipoperoxidation and scavengers of oxygen species. In this study, the capacity of total and ethyl-acetate extracts from dried pharmaceutical flowers, tops and fruits to inhibit Cu(2+)-induced LDL oxidation was tested. This capacity was positively linked to their content in total polyphenols, proanthocyanidins (global and oligomeric forms), as well as to their content in two individual phenolics: a flavanol, the dimeric procyanidin B2 and a flavonol glycoside, hyperoside. Flavanol-type phenolics showed to be higher active than the majority of the flavonoids tested in inhibiting Cu(2+)-induced LDL peroxidation. This study suggests that hawthorn could be a source of polyphenols able to inhibit LDL oxidation.
Assuntos
Biflavonoides , Crataegus/química , Lipoproteínas LDL/metabolismo , Proantocianidinas , Acetatos , Antioxidantes/química , Antioxidantes/farmacologia , Catequina/química , Catequina/farmacologia , Cromatografia Líquida de Alta Pressão , Colorimetria , Cobre/química , Flavonoides/química , Flavonoides/farmacologia , Humanos , Lipoproteínas LDL/sangue , Lipoproteínas LDL/química , Oxirredução , Fenóis/química , Fenóis/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , SolventesRESUMO
The interest of polyphenolics as therapeutic agents against diseases involving radical damage is growing. The phenolic contents of the hulls and flour from the seeds of Fagopyrum esculentum (French variety 'La Harpe') (total phenols, flavonoids, total flavanols, oligomeric proanthocyanidins) are compared with the antioxidative effects of the extracts against reactive oxygen species: hydrogen peroxide, hypochlorous acid, superoxide anion. The higher efficiency of the flour extract can be related to its higher flavanolic content rather than to flavonoids which are predominant in the hull extract.
