Significant advances have been achieved during the past decade concerning the metabolism of polyphenol compounds in vitro,
but scarce data has been presented about what really happens in vivo. Many studies on polyphenols to date have focused on the bioactivity
of one specific molecule in aglycone form, often at supraphysiological doses, whereas foods contain complex, often poorly characterized
mixtures with multiple additive or interfering activities.
Whereas most studies up to the middle-late 1990s measured total aglycones in plasma and urine, after chemical or enzymatic deconjugation,
or both, several recent works now report the polyphenol conjugate composition of plasma, urine, feces and/or tissues, after the administration
of pure polyphenols or polyphenol-rich matrices. HPLC methods with electrochemical, mass spectrometric and fluorescence
detection have adequate sensitivity. LC/UV-Vis methods have also been widely reported, but they are much less sensitive. Compared
with electro-chemical and fluorescence detection, MS can quantify analytes without chromatographic separation, which leads to high
throughput, presenting itself as the best choice to date. Regarding the experimental model to monitor the bioavailability of phenolic compounds,
most published studies are based on human and animal models, with the majority using rodents, primates and recently the nematode
Caenorhabditis elegans. This review focuses on the fundamentals of pharmacokinetic methods from the last 15 years and how the
results are evaluated and validated. The types of analytical methods, animal models and biological matrices were used to better elucidate
pharmacokinetics of polyphenols.