title: Isolation and identification of twelve metabolites of isocorynoxeine in rat urine and their neuroprotective activities in HT22 cell assay.
abstract: Isocorynoxeine, one of the major alkaloids from Uncaria Hook, shows the effects of lowering blood pressure, vasodilatation, and protection against ischemia-induced neuronal damage. In this paper, the metabolism of isocorynoxeine was investigated in rats. Twelve metabolites and the parent drug were isolated by using solvent extraction and repeated chromatographic methods, and determined by spectroscopic methods including UV, MS, NMR, and CD experiments. Seven new compounds were identified as 11-hydroxyisocorynoxeine, 5-oxoisocorynoxeinic acid-22-O-β-D-glucuronide, 10-hydroxyisocorynoxeine, 17-O-demethyl-16,17-dihydro-5-oxoisocorynoxeine, 5-oxoisocorynoxeinic acid, 21-hydroxy-5-oxoisocorynoxeine, and oxireno[18, 19]-5-oxoisocorynoxeine, together with six known compounds identified as isocorynoxeine, 18,19-dehydrocorynoxinic acid, 18,19-dehydrocorynoxinic acid B, corynoxeine, isocorynoxeine-N-oxide, and corynoxeine-N-oxide. Possible metabolic pathways of isocorynoxeine are proposed. Furthermore, the activity assay for the parent drug and some of its metabolites showed that isocorynoxeine exhibited a significant neuroprotective effect against glutamate-induced HT22 cell death at the maximum concentration. However, little or weak neuroprotective activities were observed for M-3, M-6, M-7, and M-10. Our present study is important to further understand their metabolic fate and disposition in humans.
authors.affiliation: Department of Traditional Chinese Medicines, Shenyang Pharmaceutical University, Shenyang, People's Republic of China.
authors.forename: Wen
authors.initials: W
authors.lastname: Qi
authors.affiliation: Department of Traditional Chinese Medicines, Shenyang Pharmaceutical University, Shenyang, People's Republic of China.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Chen
authors.affiliation: Center for Basic and Translational Stroke Research, Department of Physiology and Pharmacology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, United States.
authors.forename: Jiahong
authors.initials: J
authors.lastname: Sun
authors.affiliation: Center for Basic and Translational Stroke Research, Department of Physiology and Pharmacology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, United States.
authors.forename: James W
authors.initials: JW
authors.lastname: Simpkins
authors.affiliation: Department of Traditional Chinese Medicines, Shenyang Pharmaceutical University, Shenyang, People's Republic of China.
authors.forename: Dan
authors.initials: D
authors.lastname: Yuan
mesh_terms: D000284:Administration, Oral; D000470:Alkaloids / Q000737:chemistry / Q000652:urine; D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line / Q000187:drug effects; D002942:Circular Dichroism; D018698:Glutamic Acid / Q000494:pharmacology; D026121:Indole Alkaloids / Q000008:administration & dosage / Q000378:metabolism* / Q000652:urine; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051379:Mice; D015394:Molecular Structure; D009284:Naphthols / Q000737:chemistry / Q000652:urine; D018696:Neuroprotective Agents / Q000494:pharmacology*; D017208:Rats, Wistar; D032070:Uncaria / Q000737:chemistry
chemical_list: C531542:18,19-dehydrocorynoxinic acid B; D000470:Alkaloids; D026121:Indole Alkaloids; D009284:Naphthols; D018696:Neuroprotective Agents; C054799:corynoxeine; C009957:5,6-dihydroxy-2-dimethylaminotetralin; D018698:Glutamic Acid