title: Method for analysis of tannic acid and its metabolites in biological samples: application to tannic acid metabolism in the rat.
abstract: A new analytical method for measuring tannic acid (TA) using tannase was developed and applied to the investigation of TA metabolism in the rat following oral administration at a dose of 1.0 g/kg. The proposed method for TA determination was based on the enzymatic hydrolysis of TA to gallic acid (GA) and subsequent determination by HPLC. TA metabolites were determined by HPLC. 4-O-Methylgallic acid (4-OMGA), pyrogallol (PY), and resorcinol (RE) were detected in serum. TA was excreted into urine as GA (0.01%), 4-OMGA (0.10%), PY (0.24%), and RE (2.06%) and into feces as TA (62.74%), GA (0.19%), PY (0.02%), and RE (0.76%) within 54 h after oral administration. It was suggested that >60% of TA remained unchanged but that some was hydrolyzed to GA by tannase in the intestine and further metabolized to 4-OMGA, PY, and RE.
authors.affiliation: National Institute of Health Sciences, Osaka Branch, 1-1-43 Hoenzaka, Chuo-ku, Japan. ynakamura@nihs.go.jp
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Sumiko
authors.initials: S
authors.lastname: Tsuji
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Tonogai
mesh_terms: D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005243:Feces / Q000737:chemistry; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood / Q000378:metabolism / Q000652:urine; D047348:Hydrolyzable Tannins / Q000032:analysis* / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D011748:Pyrogallol / Q000032:analysis / Q000097:blood / Q000652:urine; D051381:Rats; D017208:Rats, Wistar; D012118:Resorcinols / Q000032:analysis / Q000097:blood / Q000652:urine
chemical_list: D047348:Hydrolyzable Tannins; D012118:Resorcinols; D011748:Pyrogallol; C024272:3,5-dihydroxy-4-methoxybenzoic acid; D005707:Gallic Acid; D002265:Carboxylic Ester Hydrolases; C022711:tannase; C031389:resorcinol