Aim: 

there is a considerable interest in antioxidants as bioactive components of food and as nutritional agents with a role in the maintenance of health and in disease prevention. Purpose of this work is to elucidate the antioxidant or proxidant behaviours of some polyhenolic compounds of red wine and to determinate their structure-activity relationships as antioxidants.

Methods: 

15 pure phenols were analyzed. All standard solutions were used at 1 mM in phosphate buffer, pH = 7. These compounds belong to the different polyphenol classes of red wine: phenol acids, flavan-3-ols, and flavonols. Antioxidant capacity was measured by a competition kinetics test, based on the crocin bleaching. The results was expressed as "Trolox equivalents".

Results: 

Flavonols have a higher antioxidant activity than flavan-3ols and phenolic acids. Benzoic acids were less active than the cinnamic acids. Gallic acid was the most active among analyzed compounds. The aldehyde derivatives were found to be more active than the respective acids.

Conclusion: 

The data got from this study show the different antioxidant power contribution that each of the polyphenolic compounds can bring to food depending on their chemical structure. The position and the total number of OH groups influence magnitude and mechanisms of the antioxidant activity. The introduction of a methoxy group to a phenolic structure decreases the radical scavenging capacity of the antioxidants. This study could be to investigate the antioxidant contribution of polyphenol compunds to the total antioxidant capacity of red wine.