Procyanidin B1 is detected in human serum after intake of proanthocyanidin-rich grape seed extract.

@article{Sano2003ProcyanidinBI,
  title={Procyanidin B1 is detected in human serum after intake of proanthocyanidin-rich grape seed extract.},
  author={Atsushi Sano and Jun Yamakoshi and Shoichi Tokutake and Koichiro Tobe and Yoshiro Kubota and Mamoru Kikuchi},
  journal={Bioscience, biotechnology, and biochemistry},
  year={2003},
  volume={67 5},
  pages={1140-3}
}
To confirm the absorption of proanthocyanidin (PA) into the human body, four healthy adults were administered 2.0 g of PA-rich grape seed extract (GSE). Blood were drawn before intake and 2 h after intake. Through the enzymatic treatment of sulfatase and beta-glucuronidase, blood samples were analyzed by HPLC coupled with mass-spectrometry (LC/MS). Procyanidin B1 [epicatechin-(4beta-->8)-catechin] was detected in human serum 2 h after intake. Its concentration was 10.6 +/- 2.5 nmol/l.