Oxidative and inflammatory stress represents a major risk factor for 
cardiovascular disease (CVD) in overweight and obese subjects. Between the 
different plant foods, chocolate has been shown to decrease CVD risk due to its 
antioxidant and anti-inflammatory properties. However, as we recently showed in 
epidemiological studies, meta-analyses, and human trials, dietary antioxidants 
resulted more effective in subjects characterized by an ongoing oxidative 
stress, than in healthy people. Aim of this work was to investigate the effect 
of different concentrations of chocolate phenolic extract (CPE) on in vitro free 
radical production, stimulated by phorbol 12-myristate 13-acetate (PMA), in 
leukocytes extracted from blood of normo-weight and overweight/obese subjects. 
Neutrophils from overweight/obese group had a significantly higher free radical 
production compared to the normo-weight group. In neutrophils, the lowest CPE 
concentration significantly reduced free radical production in overweight/obese 
group only, and higher CPE concentrations were effective in both groups. In 
monocytes, the CPE concentration that was significantly effective in reducing 
free radical production was lower in overweight/obese subjects than in 
normo-weight subjects. Chocolate polyphenol extracts inhibit oxidative burst in 
human neutrophils and monocytes with a higher efficiency in subjects 
characterized by an unphysiological oxidative/inflammatory stress, such as 
overweight and obese. Results of this study provide further evidence about a 
differential role of dietary antioxidant strictly related to the "stress" 
condition of the subjects.