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Zhao P, Yu Z, Huang JP, Wang L, Huang SX, Yang J. Four unreported aporphine alkaloids with antifungal activities from Artabotrys hexapetalus. Fitoterapia 2024; 174:105868. [PMID: 38378133 DOI: 10.1016/j.fitote.2024.105868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 02/14/2024] [Accepted: 02/17/2024] [Indexed: 02/22/2024]
Abstract
In this study, the extract from Artabotrys hexapetalus showed strong antifungal activity against phytopathogenic fungi in vitro. Four unreported aporphine alkaloids, hexapetalusine A-D (1-4), were isolated from stems and roots of Artabotrys hexapetalus (L.f.) Bhandari, along with six known aporphine alkaloids (5-10). Their chemical structures were elucidated by extensive spectroscopic analysis. The absolute configurations of 1-3 were determined using single-crystal X-ray diffractions and ECD calculations. Hexapetalusine A-C (1-3) were special amidic isomers. Additionally, all isolated compounds were evaluated for their antifungal activity against four phytopathogenic fungi in vitro. Hexapetalusine D (4) exhibited weak antifungal activity against Curvularia lunata. Liriodenine (5) displayed significant antifungal activity against Fusarium proliferatum and Fusarium oxysporum f. sp. vasinfectum, which is obviously better than positive control nystatin, suggesting that it had great potential to be developed into an effective and eco-friendly fungicide.
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Affiliation(s)
- Pei Zhao
- College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China; State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China; Yinchuan Hospital of Traditional Chinese Medicine, Yinchuan, China
| | - Zhiyin Yu
- College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jian-Ping Huang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Li Wang
- College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Sheng-Xiong Huang
- College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China; State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
| | - Jing Yang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
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2
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Geng Y, Li W, Wong NK, Xue F, Li Q, Zhang Y, Xu J, Deng Z, Zhou Y. Discovery of Artemisinins as Microsomal Prostaglandins Synthase-2 Inhibitors for the Treatment of Colorectal Cancer via Chemoproteomics. J Med Chem 2024; 67:2083-2094. [PMID: 38287228 DOI: 10.1021/acs.jmedchem.3c01989] [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: 01/31/2024]
Abstract
Colorectal cancer remains the second leading cause of cancer-related mortalities worldwide. While artemisinin (ART), a key active compound from the traditional Chinese medicinal herb Artemisia annua, has been recognized for its antiproliferative activity against colon cancer cells, its underlying molecular underpinnings remain elusive. Whereas promiscuity of heme-dependent alkylating of macromolecules, mainly proteins, has been seen pivotal as a universal and primary mode of action of ART in cancer cells, accumulating evidence suggests the existence of unique targets and mechanisms of actions contingent on cell or tissue specificities. Here, we employed photoaffinity probes to identify the specific targets responsible for ART's anti-colon cancer actions. Upon validation, microsomal prostaglandins synthase-2 emerged as a specific and reversible target of ART in HCT116 colorectal cancer cells, whose inhibition resulted in reduced cellular prostaglandin E2 biosynthesis and cell growth. Our discovery opens new opportunities for pharmacological treatment of colon cancer.
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Affiliation(s)
- Yiyun Geng
- School of Biotechnology and Food Engineering, Changshu Institute of Technology, Suzhou 215500, China
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China
| | - Weichao Li
- CAS Key Laboratory of Synthetic Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Nai-Kei Wong
- Clinical Pharmacology Section, Department of Pharmacology, Shantou University Medical College, Shantou 515041, China
| | - Fuchong Xue
- School of Biotechnology and Food Engineering, Changshu Institute of Technology, Suzhou 215500, China
| | - Qing Li
- School of Biotechnology and Food Engineering, Changshu Institute of Technology, Suzhou 215500, China
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China
| | - Yang Zhang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Jingyuan Xu
- School of Biotechnology and Food Engineering, Changshu Institute of Technology, Suzhou 215500, China
| | - Zhangshuang Deng
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China
| | - Yiqing Zhou
- School of Biotechnology and Food Engineering, Changshu Institute of Technology, Suzhou 215500, China
- Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China
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3
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Jameson B, Glaser R. Rotation-Inversion Isomerization of Tertiary Carbamates: Potential Energy Surface Analysis of Multi-Paths Isomerization Using Boltzmann Statistics. Chemphyschem 2023; 24:e202200442. [PMID: 36300905 DOI: 10.1002/cphc.202200442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/03/2022] [Indexed: 01/07/2023]
Abstract
Potential energy surface (PES) analyses at the SMD[MP2/6-311++G(d,p)] level and higher-level energies up to MP4(fc,SDTQ) are reported for the fluorinated tertiary carbamate N-ethyl-N-(2,2,2-trifluoroethyl) methyl carbamate (VII) and its parent system N,N-dimethyl methyl carbamate (VI). Emphasis is placed on the analysis of the rotational barrier about the CN carbamate bond and its interplay with the hybridization of the N-lone pair (NLP). All rotational transition state (TS) structures were found by computation of 1D relaxed rotational profiles but only 2D PES scans revealed the rotation-inversion paths in a compelling fashion. We found four unique chiral minima of VII, one pair each of E- and Z-rotamers, and we determined the eight unique rotational TS structures associated with every possible E/Z-isomerization path. It is a significant finding that all TS structures feature N-pyramidalization whereas the minima essentially contain sp2 -hybridized nitrogen. We will show that the TS stabilities are affected by the synergetic interplay between NLP/CO2 repulsion minimization, NLP→σ* (CO) negative hyperconjugation, and two modes of intramolecular through-space electrostatic stabilization. We demonstrate how Boltzmann statistics must be applied to determine the predicted experimental rotational barrier based on the energetics of all eight rotamerization pathways. The computed barrier for VII is in complete agreement with the experimentally measured barrier of the very similar fluorinated carbamate N-Boc-N-(2,2,2-trifluoroethyl)-4-aminobutan-1-ol II. NMR properties of VII were calculated with a variety of density functional/basis set combinations and Boltzmann averaging over the E- and Z-rotamers at our best theoretical level results in good agreement with experimental chemical shifts δ(13 C) and J(13 C,19 F) coupling constants of II (within 6 %).
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Affiliation(s)
- Brian Jameson
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri, 65401, USA
| | - Rainer Glaser
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri, 65401, USA
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4
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Xu X, Gujarati PD, Okwor N, Sivey JD, Reber KP, Xu W. Reactivity of chloroacetamides toward sulfide + black carbon: Insights from structural analogues and dynamic NMR spectroscopy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 803:150064. [PMID: 34525700 DOI: 10.1016/j.scitotenv.2021.150064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/22/2021] [Accepted: 08/27/2021] [Indexed: 06/13/2023]
Abstract
Chloroacetamides are commonly used in herbicide formulations, and their occurrence has been reported in soils and groundwater. However, how their chemical structures affect transformation kinetics and pathways in the presence of environmental reagents such as hydrogen sulfide species and black carbon has not been investigated. In this work, we assessed the impact of increasing Cl substituents on reaction kinetics and pathways of six chloroacetamides. The contribution of individual pathways (reductive dechlorination vs. nucleophilic substitution) to the overall decay of selected chloroacetamides was differentiated using various experimental setups; both the transformation rates and product distributions were characterized. Our results suggest that the number of Cl substituents affected reaction pathways and kinetics: trichloroacetamides predominantly underwent reductive dechlorination whereas mono- and dichloroacetamides transformed via nucleophilic substitution. Furthermore, we synthesized eight dichloroacetamide analogs (Cl2CHC(=O)NRR') with differing R groups and characterized their transformation kinetics. Dynamic NMR spectroscopy was employed to quantify the rotational energy barriers of dichloroacetamides. Our results suggest that adsorption of dichloroacetamides on black carbon constrained R groups from approaching the dichloromethyl carbon and subsequently favored nucleophilic attack. This study provides new insights to better predict the fate of chloroacetamides in subsurface environments by linking their structural characteristics to transformation kinetics and pathways.
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Affiliation(s)
- Xiaolei Xu
- Department of Civil and Environmental Engineering, Villanova University, Villanova, PA 19085, USA
| | | | - Neechi Okwor
- Department of Chemistry, Towson University, Towson, MD 21252, USA
| | - John D Sivey
- Department of Chemistry, Towson University, Towson, MD 21252, USA
| | - Keith P Reber
- Department of Chemistry, Towson University, Towson, MD 21252, USA
| | - Wenqing Xu
- Department of Civil and Environmental Engineering, Villanova University, Villanova, PA 19085, USA.
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Morrelli D, Guerra JG, Kumar P, Bajwa B, Krishnan V, Maitra S. Role of solvent dielectric constant on the enthalpy-entropy compensation in the hindered amide bond rotation. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Gallegos M, Costales A, Pendás ÁM. Energetic Descriptors of Steric Hindrance in Real Space: An Improved IQA Picture*. Chemphyschem 2021; 22:775-787. [PMID: 33497008 DOI: 10.1002/cphc.202000975] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/05/2021] [Indexed: 11/11/2022]
Abstract
Steric hindrance (SH) plays a central role in the modern chemical narrative, lying at the core of chemical intuition. As it however happens with many successful chemical concepts, SH lacks an underlying physically sound root, and multiple mutually inconsistent approximations have been devised to relate this fuzzy concept to computationally derivable descriptors. We here argue that being SH related to spatial as well as energetic features of interacting systems, SH can be properly handled if we chose a real space energetic stance like the Interacting Quantum Atoms (IQA) approach. Drawing on previous work by Popelier and coworkers (ChemistryOpen 8, 560, 2019) we build an energetic estimator of SH, referred to as EST . We show that the rise in the self-energy of a fragment that accompanies steric congestion is a faithful proxy for the chemist's SH concept if we remove the effect of charge transfer. This can be done rigorously, and the EST here defined provides correct sterics even for hydrogen atoms, where the plain use of deformation energies leads to non-chemical results. The applicability of EST is validated in several chemical scenarios, going from atomic compressions to archetypal SN2 reactions. EST is shown to be a robust steric hindrance descriptor.
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Affiliation(s)
- Miguel Gallegos
- Department of Analytical and Physical Chemistry, University of Oviedo, E-33006, Oviedo, Spain
| | - Aurora Costales
- Department of Analytical and Physical Chemistry, University of Oviedo, E-33006, Oviedo, Spain
| | - Ángel Martín Pendás
- Department of Analytical and Physical Chemistry, University of Oviedo, E-33006, Oviedo, Spain
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Guerra J, Bajwa B, Kumar P, Vazquez S, Krishnan VV, Maitra S. Validation of Enthalpy-Entropy Compensation Mechanism in Partial Amide Bond Rotation. ACS OMEGA 2020; 5:9348-9355. [PMID: 32363286 PMCID: PMC7191833 DOI: 10.1021/acsomega.0c00332] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
The concept of enthalpy-entropy compensation (EEC) is one of the highly debated areas of thermodynamics. The conformational change due to restricted double-bond rotation shows a classic two-site chemical exchange phenomenon and has been extensively studied. Fifty-four analogs of N,N-diethyl-m-toluamide (DEET) as a model system were synthesized to study the thermodynamics of the partial amide bond character using nuclear magnetic resonance (NMR) spectroscopy. Line-shape analysis as a function of temperature is used to estimate the chemical exchange. Eyring analysis was then used to convert the chemical exchange rates to determine the transition state enthalpy and entropy of the molecules. The experimental design follows selective variations that perturb one aspect of the molecular system and its influence on the observed thermodynamic effect. The results of the study demonstrate that amide bond resonance in analogs of DEET follows an EEC mechanism. Simple modifications made to DEET's structural motif alter both the enthalpy and entropy of the system and were limited overall to a temperature compensation factor, T β = 292.20 K, 95% CI [290.66, 293.73]. We suggest EEC as a model to describe the kinetic compensation seen in chemical exchange phenomena in analogs of DEET.
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Affiliation(s)
- Jacob Guerra
- Department
of Chemistry, California State University, Fresno, California 93740, United States
| | - Bhvandip Bajwa
- Department
of Chemistry, California State University, Fresno, California 93740, United States
| | - Prarthana Kumar
- Department
of Chemistry, California State University, Fresno, California 93740, United States
| | - Salvador Vazquez
- Department
of Chemistry, California State University, Fresno, California 93740, United States
| | - Viswanathan V. Krishnan
- Department
of Chemistry, California State University, Fresno, California 93740, United States
- Department
of Pathology & Laboratory
Medicine, University of California Davis, Davis, California 95616, United States
| | - Santanu Maitra
- Department
of Chemistry, California State University, Fresno, California 93740, United States
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Abstract
Nuclear magnetic resonance (NMR) spectroscopy is perhaps the most widely used technology from the undergraduate teaching labs in organic chemistry to advanced research for the determination of three-dimensional structure as well as dynamics of biomolecular systems... The NMR spectrum of a molecule under a given experimental condition is unique, providing both quantitative and structural information. In particular, the quantitative nature of NMR spectroscopy offers the ability to follow a reaction pathway of the given molecule in a dynamic process under well-defined experimental conditions. To highlight the use of NMR when determining the molecular thermodynamic parameters, a review of three distinct applications developed from our laboratory is presented. These applications include the thermodynamic parameters of (a) molecular oxidation from time-dependent kinetics, (b) intramolecular rotation, and (c) intermolecular exchange. An experimental overview and the method of data analysis are provided so that these applications can be adopted in a range of molecular systems.
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Nikitin K, O'Gara R. Mechanisms and Beyond: Elucidation of Fluxional Dynamics by Exchange NMR Spectroscopy. Chemistry 2019; 25:4551-4589. [PMID: 30421834 DOI: 10.1002/chem.201804123] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Indexed: 12/31/2022]
Abstract
Detailed mechanistic information is crucial to our understanding of reaction pathways and selectivity. Dynamic exchange NMR techniques, in particular 2D exchange spectroscopy (EXSY) and its modifications, provide indispensable intricate information on the mechanisms of organic and inorganic reactions and other phenomena, for example, the dynamics of interfacial processes. In this Review, key results from exchange NMR studies of small molecules over the last few decades are systemised and discussed. After a brief introduction to the theory, the key types of dynamic processes are identified and fundamental examples given of intra- and intermolecular reactions, which, in turn, could involve, or not, bond-making and bond-breaking events. Following that logic, internal molecular rotation, intramolecular stereomutation and molecular recognition will first be considered because they do not typically involve bond breaking. Then, rearrangements, substitution-type reactions, cyclisations, additions and other processes affecting chemical bonds will be discussed. Finally, interfacial molecular dynamics and unexpected combinations of different types of fluxional processes will also be highlighted. How exchange NMR spectroscopy helps to identify conformational changes, coordination and molecular recognition processes as well as quantify reaction energy barriers and extract detailed mechanistic information by using reaction rate theory in conjunction with computational techniques will be shown.
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Affiliation(s)
- Kirill Nikitin
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Ryan O'Gara
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
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