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Santis GD, Okura Y, Hirata K, Ishiuchi SI, Fujii M, Xantheas SS. Affinity of Nicotinoids to a Model Nicotinic Acetylcholine Receptor (nAChR) Binding Pocket in the Human Brain. J Phys Chem B 2024; 128:4577-4589. [PMID: 38696590 DOI: 10.1021/acs.jpcb.3c07919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2024]
Abstract
The binding affinity of nicotinoids to the binding residues of the α4β2 variant of the nicotinic acetylcholine receptor (nAChR) was identified as a strong predictor of the nicotinoid's addictive character. Using ab initio calculations for model binding pockets of increasing size composed of 3, 6, and 14 amino acids (3AA, 6AA, and 14AA) that are derived from the crystal structure, the differences in binding affinity of 6 nicotinoids, namely, nicotine (NIC), nornicotine (NOR), anabasine (ANB), anatabine (ANT), myosmine (MYO), and cotinine (COT) were correlated to their previously reported doses required for increases in intracranial self-stimulation (ICSS) thresholds, a metric for their addictive function. By employing the many-body decomposition, the differences in the binding affinities of the various nicotinoids could be attributed mainly to the proton exchange energy between the pyridine and non-pyridine rings of the nicotinoids and the interactions between them and a handful of proximal amino acids, namely Trp156, Trpβ57, Tyr100, and Tyr204. Interactions between the guest nicotinoid and the amino acids of the binding pocket were found to be mainly classical in nature, except for those between the nicotinoid and Trp156. The larger pockets were found to model binding structures more accurately and predicted the addictive character of all nicotinoids, while smaller models, which are more computationally feasible, would only predict the addictive character of nicotinoids that are similar to nicotine. The present study identifies the binding affinity of the guest nicotinoid to the host binding pocket as a strong descriptor of the nicotinoid's addiction potential, and as such it can be employed as a fast-screening technique for the potential addiction of nicotine analogs.
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Affiliation(s)
- Garrett D Santis
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Yuika Okura
- Department of Chemistry, School of Science, Tokyo Intitute of Technology; 2-12-1 4259 Ookayama, Meguro-ku, Tokyo 152855, Japan
| | - Keisuke Hirata
- Department of Chemistry, School of Science, Tokyo Intitute of Technology; 2-12-1 4259 Ookayama, Meguro-ku, Tokyo 152855, Japan
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Shun-Ichi Ishiuchi
- Department of Chemistry, School of Science, Tokyo Intitute of Technology; 2-12-1 4259 Ookayama, Meguro-ku, Tokyo 152855, Japan
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Masaaki Fujii
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
- Research and Development Initiative, Chuo University, Tokyo 112-8551, Japan
| | - Sotiris S Xantheas
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, MS K1-83, P.O. Box 999, Richland, Washington 99352, United States
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Moghbel N, Ryu B, Steadman KJ. A reversed-phase HPLC-UV method developed and validated for simultaneous quantification of six alkaloids from Nicotiana spp. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 997:142-5. [PMID: 26114650 DOI: 10.1016/j.jchromb.2015.06.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 06/08/2015] [Accepted: 06/10/2015] [Indexed: 11/23/2022]
Abstract
A reversed-phase HPLC-UV method was developed, optimized, and validated for the separation and quantitation of six target alkaloids from leaves of Nicotiana species (nicotine, nornicotine, anatabine, anabasine, myosmine, and cotinine). A bidentate reversed-phase C18 column was used as stationary phase and an alkaline ammonium formate buffer and acetonitrile as mobile phase. The alkaloids were well separated in a short run time of 13min with mobile phase pH 10.5 and a small gradient of 9-13% acetonitrile, and detected using UV at 260nm. Peak parameters were acceptable for all six closely related alkaloids. The proposed method has enough linearity with correlation coefficient >0.999 within the investigated range for all tested alkaloids. Satisfactory precision was achieved for both intra- and inter-day assay, with RSD less than 2% for all alkaloid standards. Reproducibility was also within the acceptable range of RSD <2%. Limit of detection was 1.6μg/mL for nicotine and below 1μg/mL for all other alkaloids. The limit of quantification was 2.8 and 4.8μg/mL for nornicotine and nicotine respectively, and below 2μg/mL for all other alkaloids. The method was successfully applied for simultaneous analysis of alkaloids in leaves of Nicotiana benthamiana.
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Affiliation(s)
- Nahid Moghbel
- School of Pharmacy, The University of Queensland, Brisbane, Qld 4072, Australia
| | - BoMi Ryu
- School of Pharmacy, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Kathryn J Steadman
- School of Pharmacy, The University of Queensland, Brisbane, Qld 4072, Australia.
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Dziomba S, Belka M, Kowalski P, Plenis A, Bączek T. The advances of electromigration techniques applied for alkaloid analysis. Biomed Chromatogr 2013; 27:1312-38. [DOI: 10.1002/bmc.2967] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 05/16/2013] [Accepted: 05/16/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Szymon Dziomba
- Department of Pharmaceutical Chemistry; Medical University of Gdańsk; Hallera 107; 80-416; Gdańsk; Poland
| | - Mariusz Belka
- Department of Pharmaceutical Chemistry; Medical University of Gdańsk; Hallera 107; 80-416; Gdańsk; Poland
| | - Piotr Kowalski
- Department of Pharmaceutical Chemistry; Medical University of Gdańsk; Hallera 107; 80-416; Gdańsk; Poland
| | - Alina Plenis
- Department of Pharmaceutical Chemistry; Medical University of Gdańsk; Hallera 107; 80-416; Gdańsk; Poland
| | - Tomasz Bączek
- Department of Pharmaceutical Chemistry; Medical University of Gdańsk; Hallera 107; 80-416; Gdańsk; Poland
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