Metabolism of echinacoside, a good antioxidant, in rats: isolation and identification of its biliary metabolites.

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Jia C, Shi H, Jin W, Zhang K, Jiang Y, Zhao M, Tu P

Metabolism of echinacoside, a good antioxidant, in rats: isolation and identification of its biliary metabolites.

Drug Metab Dispos. 2009 Feb;37(2):431-8. doi: 10.1124/dmd.108.023697. Epub 2008 Nov 20.

PubMed ID

19022941 [ View in PubMed

]

Abstract

Echinacoside (ECH) is one of the major active phenylethanoid glycosides (PEGs) in famous traditional Chinese medicine, Herba Cistanches. Although it has various bioactivities, such as antioxidation, neuroprotection, and hepatoprotection, knowledge about its metabolic fate is scant. In the present study, eight phase II metabolites, 3,4 -O-dimethyl-ECH-3 -O-beta-d-glucuronide (M1); 4,4 -O-dimethyl-ECH-3 -O-beta-d-glucuronide (M2); 3,4 -O-dimethyl-ECH-4-O-sulfate ester (M3); 4,4 -O-dimethyl-ECH-3-O-sulfate ester (M4); 3,3 -O-dimethyl-ECH (M5); 3,4 -O-dimethyl-ECH (M6); 4,3 -O-dimethyl-ECH (M7); and 4,4 -O-dimethyl-ECH (M8), were isolated from rat bile sample after intravenous administration of ECH and identified by mass spectra and NMR spectroscopy, including (1)H NMR, (13)C NMR, nuclear Overhauser effect difference spectroscopy, and two-dimensional NMR (heteronuclear single quantum correlation, heteronuclear multiple-bond correlation spectroscopy, gradient-selected correlation spectroscopy, and nuclear Overhauser effect spectroscopy). Among them, M5 to M8 were O-di-methylated conjugates; M1 and M2 and M3 and M4 were O-dimethyl glucuronides and O-dimethyl sulfates, respectively. In the three types of metabolites of rat, the major metabolites were the methyl ethers and the glucuronides, whereas the sulfates were minor. The regioselectivity of conjugation for ECH and metabolic pathway of ECH were proposed, which gave insight into the mechanism of ECH for its bioactivities in vivo.

DrugBank Data that Cites this Article

Drugs

Echinacoside

Drug Enzymes

Drug	Enzyme	Kind	Organism	Pharmacological Action	Actions
Echinacoside	Catechol O-methyltransferase	Protein	Humans	Unknown	Substrate	Details