pH-Dependent Forms of Red Wine Anthocyanins as Antioxidants

Abstract

Anthocyanins are one of the main classes of flavonoids in red wines, and they appear to contribute significantly to the powerful antioxidant properties of the flavonoids. In grapes and wines the anthocyanins are in the flavylium form. However, during digestion they may reach higher pH values, forming the carbinol pseudo-base, quinoidal-base, or the chalcone, and these compounds appear to be absorbed from the gut into the blood system. The antioxidant activity of these compounds, in several metal-catalyzed lipid oxidation model systems, was evaluated in comparison with other antioxidants. The pseudo-base and quinoidal-base malvidin 3-glucoside significantly inhibited the peroxidation of linoleate by myoglobin. Both compounds were found to work better than catechin, a well-known antioxidant. In a membrane lipid peroxidation system, the effectiveness of the antioxidant was dependent on the catalyst: In the presence of H(2)O(2)-activated myoglobin, the inhibition efficiency of the antioxidant was malvidin 3-glucoside > catechin > malvidin > resveratrol. However, in the presence of an iron redox cycle catalyzer, the order of effectiveness was resveratrol > malvidin 3-glucoside = malvidin > catechin. The pH-transformed forms of the anthocyanins remained effective antioxidants in these systems, and their I(50) values were between 0.5 and 6.2 microM.

Anthocyanidins and anthocyanins: colored pigments as food, pharmaceutical ingredients, and the potential health benefits

“…A previous study reports the antioxidant activity of malvidin-3-glucoside that was determined by metal-catalyzed lipid peroxidation models in comparison with other antioxidants [30]. The result shows that the quinoidal-base and pseudo-base of malvidin-3-glucoside significantly inhibited peroxidation of linoleate by myoglobin compared with catechin.…”

“…During digestion, the flavylium ion is converting to carbinol pseudo-base, quinoidal-base, or the chalcone at increasing pH before being absorbed into the blood system [30]. As mentioned earlier, anthocyanin pigment appears to be red in acidic conditions and blue to purple in alkaline solutions.…”

Effect of different calcium sources on the antioxidant stability of tortilla chips from extruded and nixtamalized blue corn (Zea mays L.) flours

“…This can be attributed to the fact that during baking and frying, the bioactive compounds such as polyphenols and anthocyanins are degraded, affecting the antioxidant activity (Lapidot et al, 1999). Some studies have reported that the presence of polyphenolics such as catechin and free forms of ferulic acid in corn flours contribute to the antioxidant activity (De la Parra et al, 2007;López-Martínez et al, 2009).…”

Aplicación de diversos métodos químicos para determinar actividad antioxidante en pulpa de frutos

“…El consumo de frutos y verduras esta asociado al bajo riesgo de incidencias y mortalidad de cáncer [7], y a menores índices de mortalidad por enfermedad coronaria [18,22], según se desprende de diversos estudios epidemiológicos. Los fenoles, especialmente los flavonoides [16] y los antocianos [9,16,24,31], muestran una gran capacidad para captar radicales libres causantes del estrés oxidativo, atribuyéndoseles a su vez un efecto beneficioso en la prevención de enfermedades tales como: cardiovasculares, circulatorias, cancerígenas y neurológicas [20,21,26,44,48,52]. Poseen actividades anti-inflamatoria, antialérgica, antitrombótica, antimicrobiana y antineoplá-sica [34,40,41,43].…”