Program

Poster Presentations

Day 3, May 17（Thu.）　　Poster

3P-30　　PDF

Oxygenation of monoterpenes by human liver microsomes

(¹Asahikawa Med. Univ., ²TMPU)
^oHiroaki Akutsu¹, Kazuhiro Sumitomo², Hiroshi Funakoshi¹, Naoyuki Hasebe¹, Masao Nakamura¹

We have reported that monoterpenes in the atmosphere of a conifer forest are transferred to and accumulate by inhalation in the walkers by walking. Gas chromatography/mass spectrometry (GC/MS) spectrum of monoterpenes in urine indicates the metabolites of transferred monoterpenes. Monoterpenes are mainly metabolized by liver microsomes. The reaction mixture contained 1 μM α-pinene or limonene, 0.4mg/ml human liver microsomes and 100 μM NADPH in 10 mM phosphate buffer (pH 7.0) were incubated at 25 ℃ for 5 hours. NADPH was added last to initiate the reaction. We exposed the solid phase microextraction (SPME) fiber to head space (HS) of vials. Reaction products in the samples were identified by GC-MS. α-Pinene- or limonene- derived oxygenated monoterpenes have been identified by GC/MS. GC/MS chromatogram of αα-pinene reaction mixture. Peaks corresponding to myrtenol, myrtenal, pinocarvone and pinanone were observed. Limonene oxide, terpineol and carveol derivatives are found in chromatogram. These oxygenated monoterpenes were not found in urine from forest walkers. The data indicate human liver P-450 has broad substrate specificity for monoterpenes. Resulting oxygenated monoterpenes would be further biotransformed and excreted in air. HS-SPME is a sensitive tool for the detection of metabolites of monoterpenes.