To evaluate the effects of a capsule formulation of an antioxidant polyphenolic extract of grapes on serum total antioxidant activity and vitamin C and E levels.Method:
A single-blinded randomised, placebo-controlled cross-over study was undertaken in 20 young volunteers. Subjects were given two capsules containing 300 mg of grape procyanidin extracts (Leucoselect™-phytosome®) or placebo daily for 5 days. Blood samples were taken at the start of the study and end of the study and assayed for antioxidant activity and vitamins C and E levels. After a washout period of at least 2 weeks, the study was repeated with the second treatment.Results:
The extract had no effect on serum vitamins C and E levels but increased serum total antioxidant activity (TAC). On day 5, TAC increased from 408·1 ± 22·9 to 453·3 ± 453·3 µmol/l trolox equivalents 1 hour postdose.Conclusion:
The capsules increased serum antioxidant activity but the longer-term clinical implications need to be assessed in further randomised clinical trials.