Short and mid-term bioavailability of flavanones from oranges in humans

Abstract

Flavanones are a group of flavonoids characteristic of citrus fruits that have been associated with hypocholesterolemic and antioxidative effects. Flavanones from oranges, mainly hesperetin and naringenin, have also been proved to be effective in the inhibition of chemically induced carcinogenesis in animal models. Although there are some studies regarding the bioavailability of flavanones from orange juice or pure compounds, the levels of hesperetin and naringenin that may be reached in plasma after the consumption of oranges in a normal diet in humans is largely unknown. The purpose of this study was to investigate the effects of single and repeated intakes of a normal amount of orange flavanones on hesperidin and naringin plasma concentrations and antioxidant activity in humans. After ingestion of 400 g of minimally processed orange fruit the levels of plasma hesperetin increased gradually throughout the study period. The maximum level of hesperetin reached in plasma was 148 nmol/L, whereas for naringenin the maximum level was only 15 nmol/L. Plasma FRAP decreased slightly during the study, however this decrease was not significant. In the multiple-doseresponse study the results showed a significant increase over the baseline levels of hesperetin in plasma after 7 and 14 days of daily ingestion of 200 g orange, thus indicating that the effect obtained after a single-dose ingestion is not predictive of the effect after a multiple-dose regimen.