Abstract
We studied the human in vivo metabolism and the elimination kinetics of α-pinene (αPN), a natural monoterpene which commonly occurs in the environment. Four volunteers were exposed to a single oral dose of 10 mg αPN. Each subject provided one pre-exposure and subsequently all post-exposure urine samples up to 24 h after administration. Additionally, blood samples were drawn hourly from two volunteers for 5 h. The analysis of the parent compound in blood was performed by a headspace GC–MS procedure, whereas the proposed αPN metabolites myrtenol (MYR) and cis- and trans-verbenol (cVER; tVER) were quantified in blood and urine using GC–PCI-MS/MS. Unknown metabolites were investigated using GC–PCI-MS full-scan analyses. The urinary concentration of the metabolites reached their maxima 1.6 h after exposure. Afterwards, they declined to the pre-exposure levels within the 24-h observation period with elimination half-lives of 1.5 h (MYR) and 1.6 h (cVER and tVER). The total eliminated amounts corresponded to 1.5 % (MYR), 5.6 % (cVER), and 4.1 % (tVER) of the orally applied dose. The GC–PCI-MS full-scan analyses identified three novel metabolites, of which one conforms to myrtenic acid (MYRA). A re-analysis of MYRA in urine showed maximum elimination 1.6 h after αPN ingestion, an elimination half-life of 1.4 h, and a share of the oral dose of 6.7 %. The study revealed that the human in vivo metabolism of αPN proceeds fast and elimination of metabolites takes places rapidly. The metabolism of αPN is dominated by extensive oxidation reactions at the methyl side-chains yielding in carboxylic acid structures as well as by allylic oxidation of the cyclohexenyl backbone, whereas predicted products of a double-bond oxidation were not detected.
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References
Adams TB, Gavin CL, McGowen MM et al (2011) The FEMA GRAS assessment of aliphatic and aromatic terpene hydrocarbons used as flavor ingredients. Food Chem Toxicol 49(10):2471–2494. doi:10.1016/j.fct.2011.06.011
Chen H, Chan KK (1997) Synthesis of deuterium labeled perillyl alcohol and dual C-13 and deuterium labeled perillic acid, major metabolites of d-limonene. J Label Compd Radiopharm 39(5):369–377. doi:10.1002/(SICI)1099-1344(199705)39:5<369::AID-JLCR983>3.0.CO;2-F
Crowell PL, Elson CE, Bailey HH, Elegbede A, Haag JD, Gould MN (1994) Human metabolism of the experimental cancer therapeutic agent d-limonene. Cancer Chemother Pharmacol 35(1):31–37. doi:10.1007/s002800050189
Demers PA, Teschke K, Davies HW, Kennedy SM, Leung V (2000) Exposure to dust, resin acids, and monoterpenes in softwood lumber mills. AIHAJ-Am Ind Hyg Assoc 61(4):521–528. doi:10.1080/15298660008984564
EFSA (2011) EFSA panel on food contact materials, enzymes, flavourings and processing aids (CEF). Consideration of aliphatic and alicyclic and aromatic hydrocarbons evaluated by JECFA (63rd meeting) structurally related to aliphatic and aromatic hydrocarbons evaluated by EFSA in FGE.25Rev2. EFSA J 9(6:2178):69. doi:10.2903/j.efsa.2011.2178
Eriksson KA, Levin JO (1990) Identification of cis- and trans-verbenol in human urine after occupational exposure to terpenes. Int Arch Occup Environ Health 62(5):379–383. doi:10.1007/BF00381368
Eriksson KA, Levin JO (1996) Gas chromatographic-mass spectrometric identification of metabolites from alpha-pinene in human urine after occupational exposure to sawing fumes. J Chromatogr B 677(1):85–98. doi:10.1016/0378-4347(95)00435-1
Geron C, Rasmussen R, Arnts RR, Guenther A (2000) A review and synthesis of monoterpene speciation from forests in the United States. Atmos Environ 34(11):1761–1781. doi:10.1016/S1352-2310(99)00364-7
Ho DX, Kim KH, Sohn JR, Oh YH, Ahn JW (2011) Emission rates of volatile organic compounds released from newly produced household furniture products using a large-scale chamber testing method. Sci World J 11:1597–1622. doi:10.1100/2011/650624
Hodgson A, Rudd A, Beal D, Chandra S (2000) Volatile organic compound concentrations and emission rates in new manufactured and site-built houses. Indoor Air 10(3):178–192
Ishida T, Asakawa Y, Takemoto T, Aratani T (1981) Terpenoids biotransformation in mammals III: biotransformation of α-pinene, β-pinene, pinane, 3-carene, carane, myrcene, and p-cymene in rabbits. J Pharm Sci 70(4):406–415. doi:10.1002/jps.2600700417
Köppel C, Tenczer J, Tönnesmann U (1981) Acute poisoning with pine oil. Metabolism of monoterpenes. Arch Toxicol 49(1):73–78. doi:10.1007/BF00352074
Levin JO, Eriksson K, Falk A, Loef A (1992) Renal elimination of verbenols in man following experimental alpha-pinene inhalation exposure. Int Arch Occup Environ Health 63(8):571–573. doi:10.1007/BF00386348
Liljelind I, Rappaport S, Eriksson K et al (2003) Exposure assessment of monoterpenes and styrene: a comparison of air sampling and biomonitoring. Occup Environ Med 60(8):599–603. doi:10.1136/oem.60.8.599
Meesters RJW, Duisken M, Jaehnigen H, Hollender J (2008) Sensitive determination of monoterpene alcohols in urine by HPLC-FLD combined with ESI-MS detection after online-solid phase extraction of the monoterpene-coumarincarbamate derivates. J Chromatogr B 875(2):444–450. doi:10.1016/j.jchromb.2008.09.024
Mercier B, Prost J, Prost M (2009) The essential oil of turpentine and its major volatile fraction (α- and β-pinenes): a review. Int J Occup Med Environ Health 22(4):331–342. doi:10.2478/v10001-009-0032-5
Passaro LC, Webster FX (2004) Synthesis of the female sex pheromone of the citrus mealybug, Planococcus citri. J Agric Food Chem 52(10):2896–2899. doi:10.1021/jf035301h
Rosenberg C, Liukkonen T, Kallas-Tarpila T et al (2002) Monoterpene and wood dust exposures: work-related symptoms among Finnish sawmill workers. Am J Ind Med 41(1):38–53. doi:10.1002/ajim.10033
Sandner F, Fornara J, Dott W, Hollender J (2002) Sensitive biomonitoring of monoterpene exposure by gas chromatographic-mass spectrometric measurement of hydroxy terpenes in urine. J Chromatogr B 780(2):225–230. doi:10.1016/S1570-0232(02)00469-5
Schmidt L, Belov VN, Göen T (2013) Sensitive monitoring of monoterpene metabolites in human urine using two-step derivatisation and positive chemical ionisation-tandem mass spectrometry. Anal Chim Acta 793:26–36. doi:10.1016/j.aca.2013.07.046
Schmidt L, Belov VN, Göen T (2015a) Human metabolism of Δ3-carene and renal elimination of Δ3-caren-10-carboxylic acid (chaminic acid) after oral administration. Arch Toxicol 89(3):381–392. doi:10.1007/s00204-014-1251-5
Schmidt L, Lahrz T, Kraft M, Göen T, Fromme H (2015b) Monocyclic and bicyclic monoterpenes in air of German daycare centers and human biomonitoring in visiting children, the LUPE 3 study. Environ Int 83:86–93. doi:10.1016/j.envint.2015.06.004
Southwell IA, Flynn TM, Degabriele R (1980) Metabolism of α- and β-pinene, β-cymene and 1,8-cineole in the brushtail possum, Trichosurus vulpecula. Xenobiotica 10(1):17–23. doi:10.3109/00498258009033726
Tsigonia A, Lagoudi A, Chandrinou S, Linos A, Evlogias N, Alexopoulos EC (2010) Indoor air in beauty salons and occupational health exposure of cosmetologists to chemical substances. Int J Environ Res Public Health 7(1):314–324. doi:10.3390/ijerph7010314#sthash.UC6ljwhL.dpuf
van der Werf MJ, Orru RVA, Overkamp KM et al (1999) Substrate specificity and stereospecificity of limonene-1,2-epoxide hydrolase from Rhodococcus erythropolis DCL14; an enzyme showing sequential and enantioconvergent substrate conversion. Appl Microbiol Biotechnol 52(3):380–385. doi:10.1007/s002530051535
Acknowledgments
We like to thank Dr. Vladimir N. Belov (Max Planck Institute for Biophysical Chemistry MPI bpc, Göttingen) for performing the syntheses and Mr. Jürgen Bienert (MPI bpc) for recording NMR and mass spectra. Furthermore, we gratefully acknowledge the cooperation of the volunteers in the oral exposure study. This study was supported by a grant from the Adolf Rohrschneider-Stiftung (Erlangen, Germany).
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Schmidt, L., Göen, T. Human metabolism of α-pinene and metabolite kinetics after oral administration. Arch Toxicol 91, 677–687 (2017). https://doi.org/10.1007/s00204-015-1656-9
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DOI: https://doi.org/10.1007/s00204-015-1656-9