Michaela Miksits

Sulfation of resveratrol in human liver: Evidence of a major role for the sulfotransferases SULT1A1 and SULT1E1

Sulfation of resveratrol, a polyphenolic compound present in grapes and wine with anticancer and cardioprotective activities, was studied in human liver cytosol. In the presence of 3′-phosphoadenosine-5′-phosphosulfate, three metabolites (M1–3) whose structures were identified by mass spectrometry and NMR as trans-resveratrol-3-O-sulfate, trans-resveratrol-4′-O-sulfate, and trans-resveratrol-3-O-4′-O-disulfate, respectively. The kinetics of M1 formation in human liver cytosol exhibited an pattern of substrate inhibition with a Ki of 21.3 ± 8.73 µM and a Vmax/Km of 1.63 ± 0.41 µL min−1mg−1 protein. Formation of M2 and M3 showed sigmoidal kinetics with about 56-fold higher Vmax/Km values for M3 than for M2 (2.23 ± 0.14 and 0.04 ± 0.01 µL min−1 mg−1). Incubation in the presence of human recombinant sulfotransferases (SULTs) demonstrated that M1 is almost exclusively catalysed by SULT1A1 and only to a minor extent by SULT 1A2, 1A3 and 1E1, whereas M2 is selectively formed by SULT1A2. M3 is mainly catalysed by SULT1A2 and 1A3. In conclusion, the results elucidate the enzymatic pathways of resveratrol in human liver, which must be considered in humans following oral uptake of dietary resveratrol.

Glucuronidation of piceatannol by human liver microsomes: major role of UGT1A1, UGT1A8 and UGT1A10

Objectives Piceatannol, a dietary polyphenol present in grapes and wine, is known for its promising anticancer and anti‐inflammatory activity. The aim of this study was to analyse the concentration‐dependent glucuronidation of piceatannol in vitro.

In-vitro sulfation of piceatannol by human liver cytosol and recombinant sulfotransferases

Objectives The aim of this study was to investigate the concentration‐dependent sulfation of piceatannol, a dietary polyphenol present in grapes and wine and known for its promising anticancer and anti‐inflammatory activity.