"Nonconjugates of nonmethylated and 3′-O-methylated forms were at low levels compared with conjugates of nonmethylated and 3′-O-methylated forms in the plasma of the CA, EC and MIX groups (Table 1). These results suggest that (+)-catechin and (−)-epicatechin were absorbed from the digestive tract, RAPIDLY CONJUGATED and present as metabolites in plasma. This confirms the proposition by Piskula and Terao (13)."
Nonconjugates of nonmethylated or 3′-O-methylated forms in the CA, EC and MIX groups were MINOR components in the plasma, especially the free 3′-O-methylated forms.
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"The oral bioavailability of catechins is known to be LOW at LESS THAN 5%"
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"It has been proposed that the first detoxification step of dietary EC, namely, glucuronidation, occurs at the level of the intestinal mucosa in rats, and EC enters the common blood circulation EXCLUSIVELY IN THE GLUCURONIZED FORM."
"Because ingested EC undergoes extensive conjugation, ITS BIOLOGICAL ACTIVITIES PREVIOUSLY DEMONSTRATED IN VITRO MAY NOT BE OCCURRING IN IN VIVO SYSTEMS."
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"the bioavailability of both compounds was LESS THAN 5%."
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Hopefully, that's more than enough to establish the issues with oral administration. Since you know a lot about TDs from your experiments, I assume we can agree that TD administration has a large body of research regarding the evasion of these first pass metabolism issues? Or do I need to prove that too?