TY - JOUR T1 - Metabolism of (2<em>S</em>)-Pterosin A: Identification of the Phase I and Phase II Metabolites in Rat Urine JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 1566 LP - 1574 DO - 10.1124/dmd.112.045039 VL - 40 IS - 8 AU - Yung-Ping Lee AU - Feng-Lin Hsu AU - Jaw-Jou Kang AU - Chien-Kuang Chen AU - Shoei-Sheng Lee Y1 - 2012/08/01 UR - http://dmd.aspetjournals.org/content/40/8/1566.abstract N2 - The metabolic profile of the potent hypoglycemic agent, (2S)-pterosin A (1), in rat urine via intragastrical oral administration was investigated. In total, 19 metabolites (M1–M19) were identified. Among these, 16 metabolites were characterized by high-performance liquid chromatography solid-phase extraction-tube transfer-NMR, and seven metabolites were further isolated from the treated urine to enable further structural determination. Twelve of these are new compounds. The phase I metabolites of 1 were formed via various oxidations at positions C-3, C-10, C-12, C-13, or C-1 followed by decarboxylation of C-10 or C-14, and lactonization at C-12/C-14 or C-14/C-12. The phase II metabolites were glucuronide conjugates from the parent compound or phase I metabolites. The major metabolites were found to be (2S)-14-O-glucuronylpterosin A (M9), (2S)-2-hydroxymethylpterosin E (M14), and (±)-pterosin B (M19). Quantitative HPLC analysis of metabolites, based on similar UV absorption and use of the regression equation of 1, indicated that ∼71% 1 was excreted as metabolites in rat urine. ER -