Studies on chemical stability of wine metal-polyphenol complexes during in vitro digestion with high performance liquid chromatography and atomic absorption spectrometry analysis

ESCUDERO, LETICIA B.; FUSARI, CECILIA; ALTAMIRANO, JORGELINA C.; CAMARGO, ALEJANDRA B.; WUILLOUD, RODOLFO G.

Foz do Iguaçu

Simposio; TWELFTH RIO SYMPOSIUM ON ATOMIC SPECTROMETRY; 2012

TWELFTH RIO SYMPOSIUM ON ATOMIC SPECTROMETRY

Polyphenols content in wines is an important parameter because of its contribution as dietary antioxidant. Phenolic acids, stilbenoids, flavonols, dihydroflavonols, anthocyanins, flavanol monomers and flavanol polymers represent major groups of polyphenols found in wine. Ingestion of these compounds has been linked to health beneficial effects, including reduced incidence of cancer and coronary heart disease [1]. The potential health effects of polyphenols depend on its bioavailability, which could be related with chemical associations to metals due to complexing capacity of some phenolic compounds [2]. In fact, it has been shown that these organic molecules, known for their antioxidant properties and their occurrence mainly in red wines, are able to form complexes with different cations. Another aspect of polyphenols bioavailability lies on their chemical stability during digestion. In vitro digestion methods have been developed for evaluating dietary wine polyphenols changes under gastric or intestinal conditions. However, digestibility of metal-polyphenol complexes has not been extensively studied and the influence of this process on metal association/dissociation to organic fractions upon wine ingestion still remains to be investigated. For this reason, the aim of this work was to develop initial studies on metal complexing capacity of eight polyphenols usually found in grape wine, namely resveratrol, catequine, quercetin, rutin, morin, naringenin, kaempferol and chlorogenic acid, with different metal ions (i.e. Fe, Cu, Zn, Mn). The in vitro digestibility of metal-polyphenol complexes was assayed following a digestion model. Thus, metal-polyphenol complexes were studied before and after in vitro gastric and intestinal digestions by high-performance liquid chromatography (HPLC) with UV-Vis detection. Adittionally, in order to reject any possibility of metal retention on the chromatographic column, all elution fractions were collected, acidified and injected directly into the graphite furnace of an electrothermal atomic absorption spectrometer (ETAAS). Furthermore, complementary studies on possible dissociation of metal-polyphenol complexes were performed by ETAAS determination of metals in the fractions obtained after HPLC separation. This is a basic study oriented to a better understanding of the nature and chemical stability of metal-polyphenol complexes under an in vitro digestion model.1. F. Paiva-Martinis, M. H. Gordon, J. Agric. Food Chem., 53:2704,20052. J. Bouayed, Current Nutrition & Food Science, 6:13,2010.