Enzyme Conversion May Improve Bioavailability of Citrus Flavonoids

SWITZERLANDResults published in the Journal of Nutrition(136, 2:404-8, 2006) from a study done at the Nestle Research Center demonstrated that enzymatic conversion of the citrus flavonoid hesperitin to hesperetin-7-glucoside can change the absorption site from the colon to the small intestine and enhance bioavailability. Sixteen volunteers completed a double blind, randomized, crossover study. They were randomly given hesperitin equivalents supplied as orange juice with natural hesperitin ("low dose"), orange juice treated with hesperidinase enzyme to yield hesperetin-7-glucoside, and orange juice fortified to obtain three times more hesperitin than naturally present ("high dose"). The peak plasma concentrations (C(max)) of hesperitin were four-times higher after subjects consumed hesperetin-7-glucoside juice compared with those consuming the "low" dose hesperitin juice and 1.5-times higher than those consuming "high" dose hesperitin juice. The corresponding T(max) was much faster (0.+/-0.1 h, P<0.0001) after subjects consumed hesperetin-7-glucoside juice compared with the "low" and high doses of hesperitin juices.