ABSTRACT
Bioavailability or pharmacokinetics of isoavones is based on data from absorption, metabolism, distribution, and excretion (ADME) studies conducted both in humans and animals. Following the consumption of pure compounds, isoavonerich extracts, or foods/beverages containing high levels of isoavones, the parent compounds and their metabolites can be detected in plasma and urine of human volunteers. Numerous studies attest to the fact that following ingestion, soy iso-avones attain maximal plasma concentrations (Cmax) within 4-8 h (Tmax) and are then eliminated from the body through the bile and kidneys with a terminal elimination half-life (t1/2) that is on average ~8 h (Setchell et al. 2001, 2003a,b; Cassidy 2006). Available data suggest that they are more efciently absorbed than other subclasses of avonoids, withCmax levels of ~2 µM and meanrelative urinary excretions of 42% for daidzein and 16% forgenistein, after a 50 mg isoavone intake (Manach et al. 2005).
