Bioavailability of the phenolic compounds of the fruits (drupes) of Olea europaea (olives): Impact on plasma antioxidant status in humans

To examine the bioavailability of olive polyphenols and to correlate it with their antioxidant efficacy, plasma and urine from healthy volunteers who had consumed 20 olives were subjected to (a) GC–MS analysis for individual phenolics, (b) estimation of plasma total polyphenol content and (c) estimation of plasma total antioxidant potential. Olive polyphenols were absorbed and metabolized within the body, occurring in plasma mainly in the conjugated form with glucuronic acid and reaching Cmax in 1–2 h. Excretion rates were maximum at 0–4 h. Tyrosol and hydroxytyrosol increased in plasma after intervention. Total antioxidant potential increased (p<0.05). The results indicate that olive polyphenols possess good bioavailability, which is in accordance with their antioxidant efficacy.