Journal article
Enteric disposition and recycling of flavonoids and ginkgo flavonoids
The journal of alternative and complementary medicine (New York, N.Y.), Vol.9(5), pp.631-640
10/2003
Handle:
https://hdl.handle.net/2376/107984
PMID: 14629841
Abstract
The objective of this study was to determine the intestinal and microbial disposition of flavonoids and how these disposition processes affect their enteric recycling.
Studies were performed using a perfused rat intestinal model or using enrichment cultures and a pure isolate of Enterococcus avium (LY1).
In the rat intestine, aglycones, such as quercetin and apigenin, were as permeable (P*(eff) > or = 2) as compounds such as propranolol (100% absorption). However, a significant portion of the absorbed aglycones was conjugated and the metabolites were excreted into the lumen. Flavonoid glycosides, such as isoquercitrin and apigenin-7-O-glucoside, also had high apparent P*(eff) values (> or = 2) in the upper small intestine because of rapid hydrolysis. However, isoquercitrin was absorbed much slower (P*(eff) < or = 0.7, p < 0.05) when hydrolysis was absent or inhibited by 20 mmol gluconolactone. Absorption of other intact glycosides was similar to intact isoquercitrin and was much slower than the corresponding aglycones (P*(eff) < or = 0.7, p < 0.05). Intestinal bacteria, such as LY1, hydrolyzed the flavonoid glycosides used in the study. Excreted glycosidases were involved in the hydrolysis of glycosides because glycosides were poorly taken up by LY1. In conclusion, glycosidase-catalyzed hydrolysis is a critical first step in the intestinal and microbial disposition of flavonoid glycosides. Aglycones were not only rapidly absorbed, but also rapidly metabolized into phase II conjugates, which were then excreted back into the lumen. Therefore, intestinal and microbial glycosidases and intestinal phase II enzymes make a significant contribution to the disposition of flavonoids via the proposed enteric and enterohepatic recycling scheme.
Metrics
8 Record Views
Details
- Title
- Enteric disposition and recycling of flavonoids and ginkgo flavonoids
- Creators
- Yong Liu - School of Molecular Biosciences, College of Pharmacy, Washington State University, Pullman, WA 99164-6584, USAYan LiuYang DaiLuying XunMing Hu
- Publication Details
- The journal of alternative and complementary medicine (New York, N.Y.), Vol.9(5), pp.631-640
- Academic Unit
- Molecular Biosciences, School of
- Publisher
- United States
- Grant note
- AT-00182 / NCCIH NIH HHS
- Identifiers
- 99900547368001842
- Language
- English
- Resource Type
- Journal article