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Toxicological evaluation of 2-dodecylcyclobutanone, a unique radiolytic compound of palmitic acid. Food Chem Toxicol 2018; 121:639-647. [PMID: 30268793 DOI: 10.1016/j.fct.2018.09.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 09/10/2018] [Accepted: 09/24/2018] [Indexed: 11/22/2022]
Abstract
This study was conducted to evaluate the toxic effects and potency of 2-dodecylcyclobutanone (2-dDCB), a unique compound derived from palmitic acid via irradiation. In a series of assays of bacterial reverse-mutation, in vitro chromosomal aberration, and in vivo micronucleus, negative responses were found by the treatment of 2-dDCB comparing vehicle control, dimethyl sulfoxide or corn oil. In the acute oral toxicity test, all of the mice administrated 2-dDCB survived, and there were no clinical and necropsy signs observed at any doses (0, 300, and 2000 mg/kg body weight) during the experimental period of 14 days. These results suggested that 2-dDCB is a relatively non-toxic substance with median lethality dose higher than 2000 mg/kg body weight. Moreover, there were no adverse effects noted in rats orally administrated 2-dDCB everyday via gavage for 28 days, even at the highest dose (2.0 mg/kg body weight/day) tested, which is 1000-times higher than the human daily intake of 2-dDCB estimated through an extreme exposure scenario. Overall, these results indicate that 2-dDCB is not likely to raise any human health concerns and irradiated foods containing palmitic acid can be recognized as safe for human consumption under the current international regulation systems for food irradiation.
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Yamakage K, Sui H, Ohta R, Toyoizumi T, Kawakami K, Matsumoto H, Takahashi T, Sasaki K, Ikezumi M, Negishi S, Izumi K, Todoriki S, Takashi K, Furuta M. Genotoxic potential and in vitro tumour-promoting potential of 2-dodecylcyclobutanone and 2-tetradecylcyclobutanone, two radiolytic products of fatty acids. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2014; 770:95-104. [PMID: 25344170 DOI: 10.1016/j.mrgentox.2014.04.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 03/16/2014] [Accepted: 04/10/2014] [Indexed: 10/25/2022]
Abstract
The DNA-damaging and tumour-promoting effects of two 2-alkylcyclobutanones (2-ACBs), which are found in irradiated fat-containing foods, were investigated by use of the comet assay and in an azoxymethane (AOM)-induced colon-carcinogenesis study in rats, respectively. We conducted genotoxicity tests of 2-dodecylcyclobutanone (2-dDCB) and 2-tetradecylcyclobutanone (2-tDCB) according to the test guidelines for chemicals or drugs. In addition, a cell-transformation assay with Bhas 42 cells was performed to investigate their promoting potential in vitro. The Salmonella typhimurium mutagenicity assay (Ames test), conducted with five tester strains, revealed that neither 2-dDCB nor 2-tDCB possessed mutagenic activity. Moreover, both in the in vitro chromosomal aberration test on CHL/IU cells and the in vivo bone-marrow micronucleus test where mice were given 2-dDCB and 2-tDCB (orally, up to 2000 mg/kg bw/day), we did not detect any clastogenic effects. Furthermore, DNA strand-breaks were not detected in the in vitro comet assay with CHL/IU cells, and DNA adducts derived from 2-dDCB and 2-tDCB were not detected in the colon tissues of the mice used for the micronucleus tests, in rats from a repeated dose 90-day oral toxicity test (0.03% 2-tDCB in the diet), or in rats from the AOM-induced carcinogenesis study (0.025% 2-tDCB in the diet). An in vitro tumour-promotion assay with Bhas 42 cells revealed that the number of transformed foci increased significantly following treatment of cells in the stationary phase with 2-dDCB or 2-tDCB for 10 days. Our results indicate that neither 2-dDCB nor 2-tDCB were genotoxic chemicals. However, they exhibited promoting activity, at least in vitro, when Bhas 42 cells were continuously exposed to these chemicals at toxic doses.
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Affiliation(s)
- Kohji Yamakage
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan.
| | - Hajime Sui
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Ryo Ohta
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Tomoyasu Toyoizumi
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Kumiko Kawakami
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Hirotaka Matsumoto
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Toshitaka Takahashi
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Kiyoshi Sasaki
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Mayu Ikezumi
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Saki Negishi
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Keisuke Izumi
- Department of Molecular and Environmental Pathology, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Setsuko Todoriki
- Food Safety Division, National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
| | - Kondo Takashi
- Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan
| | - Masakazu Furuta
- Laboratory of Quantum-Beam Chemistry and Biology, Radiation Research Center, Osaka Prefecture University, 1-2 Gakuen-cho, Sakai, Osaka 599-8570, Japan
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Song BS, Choi SJ, Jin YB, Park JH, Kim JK, Byun EB, Kim JH, Lee JW, Kim GS, Marchioni E. A critical review on toxicological safety of 2-alkylcyclobutanones. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2014.05.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Molecular mechanisms of apoptosis induction by 2-dodecylcyclobutanone, a radiolytic product of palmitic acid, in human lymphoma U937 cells. Apoptosis 2012; 17:636-45. [PMID: 22311471 DOI: 10.1007/s10495-012-0698-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The irradiation of fat-containing food forms 2-dodecylcyclobutanone (2-DCB) from palmitic acid (PA). In this study, we investigated whether 2-DCB and PA induce apoptosis in human lymphoma U937 cells. We found that cell viability decreased by 2-DCB and apoptosis was induced by 2-DCB and PA. 2-DCB and PA significantly enhanced the formation of intracellular reactive oxygen species (ROS). Apoptosis induced by 2-DCB and PA was strongly prevented by an antioxidant, N-acetyl-L: -cysteine. The treatment with 2-DCB and PA resulted in the loss of mitochondrial membrane potential, and Fas, caspase-8 and caspase-3 activation. Pretreatment with a pan-caspase inhibitor (z-VAD) significantly inhibited apoptosis induced by 2-DCB and PA. Moreover, 2-DCB and PA also induced Bax up-regulation, the reduction in Bcl-2 expression level, Bid cleavage and the release of cytochrome c from the mitochondria to the cytosol. In addition, an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) was observed after the treatment with 2-DCB and PA. Our results indicated that intracellular ROS generation, the modulation of the Fas-mitochondrion-caspase-dependent pathway and the increase in [Ca(2+)](i) involved in apoptosis are induced by 2-DCB and PA in U937 cells.
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Hijaz F, Shrestha TB, Bossman SH, Hussain F, Smith JS. In vitro and in vivo metabolism of the radiolytic compound 2-dodecylcyclobutanone. J Food Sci 2010; 75:T72-80. [PMID: 20546430 DOI: 10.1111/j.1750-3841.2010.01600.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Our knowledge about the metabolism of alkylcyclobutanones (2-ACBs) is limited, and the lack of literature on the metabolism of 2-ACBs causes consumers to doubt the safety of irradiated foods. The objectives of this study were to evaluate the metabolism of 2-dodecylcyclobutanone (2-DCB) and identify any possible metabolite. The 2-DCB was mixed with rat S9 (postmitochondrial supernatant fraction) and beta-nicotinamide adenine dinucleotide phosphate (NADPH) in phosphate buffer (pH 7.4) and incubated for 2 h at 37 degrees C. Then, the incubation mixture was mixed with sodium sulfate and extracted with n-hexane by using a Soxhlet apparatus. The hexane extract was concentrated under nitrogen and injected into the gas chromatography-mass spectrometry (GC-MS) machine running in selective ion monitoring mode (SIM) to measure 2-DCB concentration. The hexane extract from the in vitro and in vivo studies was also derivatized with a silylation reagent and injected into a GC-MS running in full scan mode. The average percentage of 2-DCB recovered from the test incubations was 23%, compared with 50% from the controls. The GC-MS chromatograms of the derivatized samples showed a unique peak in the in vitro test incubations and in the hexane extract of the rat feces that were given 2-DCB. This peak was later identified as 2-doecylcyclobutanol.
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Affiliation(s)
- Faraj Hijaz
- Food Science Inst., Dept. of Animal Sciences and Industry, 208 Call Hall, Kansas State Univ., Manhattan, KS 66506, USA
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