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Fukuyama Y, Kubo M, Harada K. Neurotrophic Natural Products. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2024; 123:1-473. [PMID: 38340248 DOI: 10.1007/978-3-031-42422-9_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.
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Affiliation(s)
- Yoshiyasu Fukuyama
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan.
| | - Miwa Kubo
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan
| | - Kenichi Harada
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan
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Ren L, Luo J, Tan L, Tang Q. Titanium-Mediated Domino Cross-Coupling/Cyclodehydration and Aldol-Addition/Cyclocondensation: Concise and Regioselective Synthesis of Polysubstituted and Fused Furans. J Org Chem 2022; 87:3167-3176. [PMID: 35133828 DOI: 10.1021/acs.joc.1c02894] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Titanium enolates, in situ-generated from readily available ketones and titanium tetraisopropoxide, undergo domino cross-coupling/cyclodehydration or domino Aldol-addition/cyclocondensation with α-chloroketones to provide synthetically valuable furan derivatives. The domino process tolerates a variety of cyclic and acyclic ketones and chloroketones, producing polysubstituted furans and bi-, tri-, and tetracyclic fused furans.
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Affiliation(s)
- Lu Ren
- College of Pharmacy, Center for Lab Teaching and Management, Chongqing Medical University, No. 1 Yixueyuan Road, Chongqing 400016, PR China
| | - Juan Luo
- College of Pharmacy, Center for Lab Teaching and Management, Chongqing Medical University, No. 1 Yixueyuan Road, Chongqing 400016, PR China
| | - Linbo Tan
- College of Pharmacy, Center for Lab Teaching and Management, Chongqing Medical University, No. 1 Yixueyuan Road, Chongqing 400016, PR China
| | - Qiang Tang
- College of Pharmacy, Center for Lab Teaching and Management, Chongqing Medical University, No. 1 Yixueyuan Road, Chongqing 400016, PR China
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Synthesis and Biological Evaluation of Diversified Hamigeran B Analogs as Neuroinflammatory Inhibitors and Neurite Outgrowth Stimulators. Mar Drugs 2020; 18:md18060306. [PMID: 32545418 PMCID: PMC7345552 DOI: 10.3390/md18060306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/07/2020] [Accepted: 06/09/2020] [Indexed: 11/16/2022] Open
Abstract
We describe the efficient synthesis of a series of new simplified hamigeran B and 1-hydroxy-9-epi-hamigeran B norditerpenoid analogs (23 new members in all), structurally related to cyathane diterpenoid scaffold, and their anti-neuroinflammatory and neurite outgrowth-stimulating (neurotrophic) activity. Compounds 9a, 9h, 9o, and 9q exhibited moderate nerve growth factor (NGF)-mediated neurite-outgrowth promoting effects in PC-12 cells at the concentration of 20 μm. Compounds 9b, 9c, 9o, 9q, and 9t showed significant nitric oxide (NO) production inhibition in lipopolysaccharide (LPS)-activated BV-2 microglial cells, of which 9c and 9q were the most potent inhibitors, with IC50 values of 5.85 and 6.31 μm, respectively. Two derivatives 9q and 9o as bifunctional agents displayed good activities as NO production inhibitors and neurite outgrowth-inducers. Cytotoxicity experiments, H2O2-induced oxidative injury assay, and ELISA reaction speculated that compounds may inhibit the TNF-α pathway to achieve anti-inflammatory effects on nerve cells. Moreover, molecular docking studies provided a better understanding of the key structural features affecting the anti-neuroinflammatory activity and displayed significant binding interactions of some derivatives (like 9c, 9q) with the active site of iNOS protein. The structure-activity relationships (SARs) were also discussed. These results demonstrated that this structural class compounds offered an opportunity for the development of a new class of NO inhibitors and NGF-like promotors.
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Harada K, Kubo M, Fukuyama Y. Chemistry and Neurotrophic Activities of (-)-Talaumidin and Its Derivatives. Front Chem 2020; 8:301. [PMID: 32391327 PMCID: PMC7192021 DOI: 10.3389/fchem.2020.00301] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/26/2020] [Indexed: 12/05/2022] Open
Abstract
(–)-Talaumidin (1), a 2,5-biaryl-3,4-dimethyltetrahydrofuran lignan isolated from Aristolochia arcuata Masters, exhibits significant neurite-outgrowth promotion and neuroprotection in primary cultured rat cortical neurons and in NGF-differentiated PC12 cells. The first enantioselective total synthesis of 1 was achieved by a flexible and reliable synthetic pathway involving an Evans asymmetric aldol reaction, as well as a stereocontrolled hydroboration and Friedel–Crafts arylation, to construct the four contiguous chiral centers on the tetrahydrofuran (THF) ring of 1. In order to investigate the stereochemistry–activity relationship of 1, a systematic synthesis of all diastereomers of 1 was accomplished by applying the synthetic strategy used for natural product 1. The evaluation of neurite-outgrowth promotion by all of the synthesized diastereomers indicated that the (–)-(1S,2R,3S,4R)-isomer 1e was significantly more active than naturally occurring 1. Additionally, we established a synthetic methodology for talaumidin derivatives that could be used to prepare a variety of analogs in a few steps and on a large scale. The synthesized racemic analog rac-1e (56a) exhibited neurite-outgrowth promoting activity in NGF-differentiated PC12 cells to the same degree as the optically active (–)-1e, revealing that a relative configuration bearing all-cis- substituents is important for potent neurotrophic activity, whilst the absolute configuration does not affect activity. Fourteen analogs based on (±)-56a were prepared via the same synthetic methodology. Among them, 56b with a methylenedioxy group on both benzene rings was found to exhibit the most significant neurite outgrowth promotion. In addition, 56a and 56b induced regeneration of the mouse optic nerve in vivo, and their activity was higher than that of talaumidin, as well as their in vitro measured activity. Furthermore, the structure–activity relationship of 56b indicated that the two benzene rings were essential structures, and that the methyl groups on the THF ring could enhance the neurotrophic activity. This result suggests that the two benzene rings of the talaumidin derivatives are essential structures for neurotrophic activity, while the two methyl groups on the THF ring can enhance neurite-outgrowth activity. Finally, it was observed that 1 and derivatives 56a and 56b exhibited potent regenerative activity in the injured mouse optic nerve in vivo.
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Affiliation(s)
- Kenichi Harada
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan
| | - Miwa Kubo
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan
| | - Yoshiyasu Fukuyama
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan
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Harada K. [Development of New Neurotrophic Compounds Based on Talaumidin]. YAKUGAKU ZASSHI 2020; 140:129-137. [PMID: 32009033 DOI: 10.1248/yakushi.19-00167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
(-)-2S,3S,4S,5S-Talaumidin (1) exhibits potent neurotrophic activities such as neurite-outgrowth promotion and neuroprotection in primary cultured rat cortical neurons and in nerve growth factor (NGF)-differentiated PC12 cells. To examine the stereochemistry-activity relationship of 1, systematic syntheses of seven stereoisomers of 1 were accomplished via Evans aldol reaction, diastereoselective hydroboration, and Mitsunobu reaction. All stereoisomers showed moderate-to-potent neurite-outgrowth promotion in NGF-differentiated PC12 cells. In particular, (-)-2S,3R,4S,5R-1e having all-cis-substituted configuration exhibited the most significant neurite-outgrowth promotion. Subsequently, we developed a short-step synthetic route for talaumidin derivatives so as to explore new neurotrophic compounds that could be obtained on a large scale. First, we synthesized derivative 2a, which is a racemic compound of (-)-1e, and compared its neurotrophic activity with (-)-1e. It was found that the neurotrophic activity of racemic 2a was similar to that of (-)-1e. Using the same synthetic route, several talaumidin derivatives were synthesized to optimize the oxy-functionality on aromatic rings. Thereby, bis(methylenedioxybenzene) derivative 2b was found to exhibit the highest neurotrophic activity. In addition, examination of the structure-activity relationship of 2b indicated that the 2,5-diphenyl structure was crucial moiety, and the two methyl groups on the tetrahydrofuran (THF) ring could enhance the neurotrophic activity. Furthermore, 2a and 2b were found to induce mouse optic nerve regeneration in vivo.
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Affiliation(s)
- Kenichi Harada
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University
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Alfonzo E, Beeler AB. A sterically encumbered photoredox catalyst enables the unified synthesis of the classical lignan family of natural products. Chem Sci 2019; 10:7746-7754. [PMID: 31588322 PMCID: PMC6761868 DOI: 10.1039/c9sc02682g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 06/30/2019] [Indexed: 11/21/2022] Open
Abstract
Herein, we detail a unified synthetic approach to the classical lignan family of natural products that hinges on divergence from a common intermediate that was strategically identified from nature's biosynthetic blueprints.
Herein, we detail a unified synthetic approach to the classical lignan family of natural products that hinges on divergence from a common intermediate that was strategically identified from nature's biosynthetic blueprints. Efforts toward accessing the common intermediate through a convergent and modular approach resulted in the discovery of a sterically encumbered photoredox catalyst that can selectively generate carbonyl ylides from electron-rich epoxides. These can undergo concerted [3 + 2] dipolar cycloadditions to afford tetrahydrofurans, which were advanced (2–4 steps) to at least one representative natural product or natural product scaffold within all six subtypes in classical lignans. The application of those synthetic blueprints to the synthesis of heterolignans bearing unnatural functionality was demonstrated, which establishes the potential of this strategy to accelerate structure–activity-relationship studies of these natural product frameworks and their rich biological activity.
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Affiliation(s)
- Edwin Alfonzo
- Department of Chemistry , Boston University , Boston , Massachusetts 02215 , USA .
| | - Aaron B Beeler
- Department of Chemistry , Boston University , Boston , Massachusetts 02215 , USA .
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Zálešák F, Bon DJYD, Pospíšil J. Lignans and Neolignans: Plant secondary metabolites as a reservoir of biologically active substances. Pharmacol Res 2019; 146:104284. [PMID: 31136813 DOI: 10.1016/j.phrs.2019.104284] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 05/21/2019] [Accepted: 05/22/2019] [Indexed: 12/19/2022]
Abstract
Lignans and neolignans are plant secondary metabolites derived from the oxidative coupling of phenylpropanoids. Biological activity of these phenolic compounds ranges from antioxidant, antitumor (terminaloside P, IC50 = 10 nM), anti-inflammatory, anti-neurodegenerative (schibitubin B, IC50 = 3.2 nM) and antiviral (patentiflorin A, IC50 = 14-23 nM) to antimicrobial. In addition, it was observed that several members of this group, namely enterolactone and its biochemical precursors also known as phytoestrogens, possess important protective properties. Most of these lignans and neolignans are presented in reasonable amounts in one's diet and thus the protection they provide against the colon and breast cancer, to name a few, is even more important to note. Similarly, neuroprotective properties were observed (schisanwilsonin G, IC50 = 3.2 nM) These structural motives also serve as an important starting point in the development of anticancer drugs. Presumably the most famous members of this family, etoposide and teniposide, synthetic derivatives of podophyllotoxin, are used in the clinical treatment of lymphocytic leukemia, certain brain tumors, and lung tumors already for nearly 20 years. This review describes 413 lignans and neolignans which have been isolated between 2016 and mid-2018 being reported in more than 300 peer-reviewed articles. It covers their source, structure elucidation, and bioactivity. Within the review, the structure-based overview of compounds as well as the bioactivity-based overview of compounds are described.
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Affiliation(s)
- František Zálešák
- Department of Organic Chemistry, Faculty of Science, Palacky University, tř. 17. listopadu 1192/12, CZ-771 46 Olomouc, Czech Republic.
| | - David Jean-Yves Denis Bon
- Department of Organic Chemistry, Faculty of Science, Palacky University, tř. 17. listopadu 1192/12, CZ-771 46 Olomouc, Czech Republic.
| | - Jiří Pospíšil
- Department of Organic Chemistry, Faculty of Science, Palacky University, tř. 17. listopadu 1192/12, CZ-771 46 Olomouc, Czech Republic; Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic.
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