Among the five administered prototypes, icariin alone was not observed in the hydrolyzed plasma, but its deglycosylated metabolite, BaoI, was detected.
Among the five active prenylflavonoid prototypes (EpiA, EpiB, EpiC, icariin, and BaoI) and the five deglycosylated metabolites (SagA, SagB, 2"-rha-icaII, IcaI, and icaritin), icaritin was the only compound to exist in hydrolyzed plasma after the administration of the five prototypes.
EpiA, EpiB, EpiC, and BaoI concentrations in hydrolyzed plasma reached 3-10 ng/ml within 0.3-1.6 h after EWH extract administration.
Collectively, our analyses reduced the number of potential pharmacokinetic markers in hydrolyzed plasma to five: four prototypes with rapid-elimination (EpiA, EpiB, EpiC, and BaoI), representative of intestinal absorption, and one icaritin, whose elimination profile was representative of systemic prenylflavonoid exposure.
As described in the previous section, ten potential pharmacokinetic markers were condensed to four prototypes (EpiA, EpiB, EpiC, and BaoI) and one deglycosylated metabolite (icaritin) in hydrolyzed plasma.
Icariin served as a representative of diglycosides, but because icariin is rapidly biotransformed into BaoI, the latter was used for correlation analysis.
The exposure levels of five prototype prenylflavonoids, with BaoI level representing icariin level, in hydrolyzed rat plasma only indicated their corresponding exposure levels in unhydrolyzed rat plasma.