ACS Publications. Most Trusted. Most Cited. Most Read
Chemical Composition of the Bark of Tetrapterys mucronata and Identification of Acetylcholinesterase Inhibitory Constituents
My Activity

    Article

    Chemical Composition of the Bark of Tetrapterys mucronata and Identification of Acetylcholinesterase Inhibitory Constituents
    Click to copy article linkArticle link copied!

    View Author Information
    Núcleo de Bioensaios, Biossíntese e Ecofisiologia de Produtos Naturais, NuBBE, Instituto de Química, Universidade Estadual Paulista (UNESP), Araraquara, São Paulo, Brazil
    School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 30, Quai Ernest-Ansermet, CH-1211, Geneva 4, Switzerland
    § Division of Pharmaceutical Biology, University of Basel, Klingelbergrstrasse 50, CH-4056, Basel, Switzerland
    *Tel: ++ 41 22 379 3641. Fax: ++41 22 379 33 99. E-mail: [email protected]
    *Tel: ++55 16 3301 9660. Fax: ++55 16 3322 2308. E-mail: [email protected]
    Other Access OptionsSupporting Information (1)

    Journal of Natural Products

    Cite this: J. Nat. Prod. 2014, 77, 3, 650–656
    Click to copy citationCitation copied!
    https://doi.org/10.1021/np401003p
    Published February 12, 2014
    Copyright © 2014 The American Chemical Society and American Society of Pharmacognosy

    Abstract

    Click to copy section linkSection link copied!
    Abstract Image

    The secondary metabolite content of Tetrapterys mucronata, a poorly studied plant that is used occasionally in Brazil for the preparation of a psychotropic plant decoction called “Ayahuasca”, was determined to establish its chemical composition and to search for acetylcholinesterase (AChE) inhibitors. The ethanolic extract of the bark of T. mucronata exhibited in vitro AChE inhibition in a TLC bioautography assay. To localize the active compounds, biological profiling for AChE inhibition was performed using at-line HPLC-microfractionation in 96-well plates and subsequent AChE inhibition bioautography. The analytical HPLC-PDA conditions were transferred geometrically to a preparative medium-pressure liquid chromatography column using chromatographic calculations for the efficient isolation of the active compounds at the milligram scale. Twenty-two compounds were isolated, of which six are new natural products. The structures of the new compounds (9, 10, 1618, and 20) were elucidated by spectroscopic data interpretation. Compounds 1, 5, 6, 9, and 10 inhibited AChE with IC50 values below 15 μM.

    Copyright © 2014 The American Chemical Society and American Society of Pharmacognosy

    Read this article

    To access this article, please review the available access options below.

    Get instant access

    Purchase Access

    Read this article for 48 hours. Check out below using your ACS ID or as a guest.

    Recommended

    Access through Your Institution

    You may have access to this article through your institution.

    Your institution does not have access to this content. Add or change your institution or let them know you’d like them to include access.

    Supporting Information

    Click to copy section linkSection link copied!

    This material is available free of charge via the Internet at http://pubs.acs.org.

    Terms & Conditions

    Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

    Cited By

    Click to copy section linkSection link copied!
    Citation Statements
    Explore this article's citation statements on scite.ai

    This article is cited by 51 publications.

    1. Wilailak Saetae, Chayamon Chantana, Saowanit Saithong, Kampanart Chayajarus, Jaray Jaratjaroonphong. Short Total Synthesis of (+)-Colletotryptins B-D and Mucronatin B Derivative. The Journal of Organic Chemistry 2024, 89 (12) , 8620-8631. https://doi.org/10.1021/acs.joc.4c00552
    2. Helena Mannochio-Russo, Wilhan D. G. Nunes, Rafael F. Almeida, Lorena C. Albernaz, Laila S. Espindola, Vanderlan S. Bolzani. Old Meets New: Mass Spectrometry-Based Untargeted Metabolomics Reveals Unusual Larvicidal Nitropropanoyl Glycosides from the Leaves of Heteropterys umbellata. Journal of Natural Products 2023, 86 (3) , 621-632. https://doi.org/10.1021/acs.jnatprod.2c00788
    3. Zhengyu Han, Wenlong Wang, Han Zhuang, Jie Wang, Cheng Wang, Jianhao Wang, Hai Huang, Jianwei Sun. Catalytic Enantioselective Synthesis of 2,3′-Bis(indolyl)methanes Bearing All-Carbon Quaternary Stereocenters via 2-Indole Imine Methides. Organic Letters 2023, 25 (3) , 477-482. https://doi.org/10.1021/acs.orglett.2c04109
    4. Kang Dong, Jia Li, Rui-Peng Li, Mingming Mao, Jian Liu, Xiaolei Wang, Shouchu Tang. One-Pot Sequential Synthesis of 3,3′- or 2,3′-Bis(indolyl)methanes by Using 1,3-Dithiane as the Methylene Source. The Journal of Organic Chemistry 2022, 87 (21) , 14930-14939. https://doi.org/10.1021/acs.joc.2c01844
    5. Chayamon Chantana, Jaray Jaratjaroonphong. FeCl3·6H2O as a Mild Catalyst for Nucleophilic Substitution of Symmetrical Bis(indoyl)methanes. The Journal of Organic Chemistry 2021, 86 (3) , 2312-2327. https://doi.org/10.1021/acs.joc.0c02466
    6. Helena Mannochio-Russo, Paula Carolina P. Bueno, Anelize Bauermeister, Rafael Felipe de Almeida, Pieter C. Dorrestein, Alberto José Cavalheiro, Vanderlan S. Bolzani. Can Statistical Evaluation Tools for Chromatographic Method Development Assist in the Natural Products Workflow? A Case Study on Selected Species of the Plant Family Malpighiaceae. Journal of Natural Products 2020, 83 (11) , 3239-3249. https://doi.org/10.1021/acs.jnatprod.0c00495
    7. Euan B. McLean, Francesca M. Cutolo, Orla J. Cassidy, David J. Burns, Ai-Lan Lee. Selectivity Control in Gold-Catalyzed Hydroarylation of Alkynes with Indoles: Application to Unsymmetrical Bis(indolyl)methanes. Organic Letters 2020, 22 (17) , 6977-6981. https://doi.org/10.1021/acs.orglett.0c02526
    8. Yuan Ling, Di An, Yuanyuan Zhou, Weidong Rao. Ga(OTf)3-Catalyzed Temperature-Controlled Regioselective Friedel–Crafts Alkylation of Trifluoromethylated 3-Indolylmethanols with 2-Substituted Indoles: Divergent Synthesis of Trifluoromethylated Unsymmetrical 3,3′-and 3,6′-Bis(indolyl)methanes. Organic Letters 2019, 21 (9) , 3396-3401. https://doi.org/10.1021/acs.orglett.9b01135
    9. Ying-Ying He, Xiao-Xue Sun, Guo-Hao Li, Guang-Jian Mei, and Feng Shi . Substrate-Controlled Regioselective Arylations of 2-Indolylmethanols with Indoles: Synthesis of Bis(indolyl)methane and 3,3′-Bisindole Derivatives. The Journal of Organic Chemistry 2017, 82 (5) , 2462-2471. https://doi.org/10.1021/acs.joc.6b02850
    10. Paul Coulerie, Yann Ratinaud, Sofia Moco, Loraine Merminod, Martine Naranjo Pinta, Julien Boccard, Laurent Bultot, Maria Deak, Kei Sakamoto, Emerson Ferreira Queiroz, Jean-Luc Wolfender, and Denis Barron . Standardized LC×LC-ELSD Fractionation Procedure for the Identification of Minor Bioactives via the Enzymatic Screening of Natural Extracts. Journal of Natural Products 2016, 79 (11) , 2856-2864. https://doi.org/10.1021/acs.jnatprod.6b00628
    11. Tingting Wang, Zhanhui Yang. Sterically Directed Site‐ and Stereoselective O ‐Glycosylation of tert ‐Butyl Gentisate. Chemistry – An Asian Journal 2025, https://doi.org/10.1002/asia.202500359
    12. Mohd Kamil Hussain, Moazzam Ahmad, Shahnaaz Khatoon, Mohsin Vahid Khan, Sarfuddin Azmi, Md Arshad, Shakir Ahamad, Mohammad Saquib. Phytomolecules as Alzheimer's therapeutics: A comprehensive review. European Journal of Medicinal Chemistry 2025, 288 , 117401. https://doi.org/10.1016/j.ejmech.2025.117401
    13. Minakshi Ghosh, Shuvendu Saha, Modhu Sudan Maji. Reversed Allylation of 3‐Alkenyl Indoles Using Allyl Boronic Acids: Access to Tryptamine Based Alkaloids. Chemistry – A European Journal 2025, 31 (11) https://doi.org/10.1002/chem.202403966
    14. Emerson Ferreira Queiroz, Davy Guillarme, Jean-Luc Wolfender. Advanced high-resolution chromatographic strategies for efficient isolation of natural products from complex biological matrices: from metabolite profiling to pure chemical entities. Phytochemistry Reviews 2024, 23 (5) , 1415-1442. https://doi.org/10.1007/s11101-024-09928-w
    15. Ana Paula Murray, Brunella Biscussi, Valeria Cavallaro, Martina Donozo, Silvana A. Rodriguez. Naturally Occurring Cholinesterase Inhibitors from Plants, Fungi, Algae, and Animals: A Review of the Most Effective Inhibitors Reported in 2012-2022. Current Neuropharmacology 2024, 22 (10) , 1621-1649. https://doi.org/10.2174/1570159X21666230623105929
    16. Berrak Ertugrul, Abdulmelik Aytatli, Omer Faruk Karatas, Nurullah Saracoglu. Design, synthesis, and biological evaluation of indole-modified tamoxifen relatives as potent anticancer agents. RSC Medicinal Chemistry 2023, 14 (7) , 1362-1376. https://doi.org/10.1039/D3MD00157A
    17. Qiwen Pang, Wei‐Fang Zuo, Yang Zhang, Xiang Li, Bo Han. Recent Advances on Direct Functionalization of Indoles in Aqueous Media. The Chemical Record 2023, 23 (3) https://doi.org/10.1002/tcr.202200289
    18. Jirapat Yimyaem, Chayamon Chantana, Suthimon Boonmee, Jaray Jaratjaroonphong. Expedient Access to Indolyl-Substituted Tri- and Diarylmethanes and (±)-Colletotryptin E by Silica Sulfuric Acid Catalyzed Transindolylation. Synlett 2022, 33 (14) , 1363-1370. https://doi.org/10.1055/s-0040-1719915
    19. Bálint Lőrinczi, Péter Simon, István Szatmári. Synthesis of Indole-Coupled KYNA Derivatives via C–N Bond Cleavage of Mannich Bases. International Journal of Molecular Sciences 2022, 23 (13) , 7152. https://doi.org/10.3390/ijms23137152
    20. Helena Mannochio-Russo, Rafael F. de Almeida, Wilhan D. G. Nunes, Paula C. P. Bueno, Andrés M. Caraballo-Rodríguez, Anelize Bauermeister, Pieter C. Dorrestein, Vanderlan S. Bolzani. Untargeted Metabolomics Sheds Light on the Diversity of Major Classes of Secondary Metabolites in the Malpighiaceae Botanical Family. Frontiers in Plant Science 2022, 13 https://doi.org/10.3389/fpls.2022.854842
    21. Robin Huber, Laurence Marcourt, Alexey Koval, Sylvain Schnee, Davide Righi, Emilie Michellod, Vladimir L. Katanaev, Jean-Luc Wolfender, Katia Gindro, Emerson Ferreira Queiroz. Chemoenzymatic Synthesis of Complex Phenylpropanoid Derivatives by the Botrytis cinerea Secretome and Evaluation of Their Wnt Inhibition Activity. Frontiers in Plant Science 2022, 12 https://doi.org/10.3389/fpls.2021.805610
    22. Wen-Run Zhu, Qiong Su, Xiao-Yi Deng, Jia-Sheng Liu, Tao Zhong, Shan-Shui Meng, Ji-Tao Yi, Jiang Weng, Gui Lu. Organocatalytic enantioselective S N 1-type dehydrative nucleophilic substitution: access to bis(indolyl)methanes bearing quaternary carbon stereocenters. Chemical Science 2021, 13 (1) , 170-177. https://doi.org/10.1039/D1SC05174A
    23. Chao ZHAO, Min CHEN, Shan-Liang SUN, Jiao-Jiao WANG, Yue ZHONG, Huan-Huan CHEN, He-Min LI, Han XU, Nian-Guang LI, Hong-Yue MA, Xiao-Long WANG. Bufotenine and its derivatives: synthesis, analgesic effects identification and computational target prediction. Chinese Journal of Natural Medicines 2021, 19 (6) , 454-463. https://doi.org/10.1016/S1875-5364(21)60044-4
    24. Alaa A. Atia, Masanari Kimura. Pd-porphyrin complex-catalyzed allylation of indole with allylic alcohols through C3–C2 coupling. Tetrahedron 2021, 90 , 132213. https://doi.org/10.1016/j.tet.2021.132213
    25. Zhen-yu Lu, Jin-tao Hu, Wei-qiao Lan, Xiao-qing Mo, Shuang Zhou, Yue-fan Tang, Wei-cheng Yuan, Xiao-mei Zhang, Li-hua Liao. Enantioselective synthesis of hetero-triarylmethanes by chiral phosphoric acid-catalyzed 1,4-addition of 3-substituted indoles with azadienes. Tetrahedron Letters 2021, 67 , 152862. https://doi.org/10.1016/j.tetlet.2021.152862
    26. Thanigaimalai Pillaiyar, Masoud Sedaghati, Andhika B. Mahardhika, Lukas L. Wendt, Christa E. Müller. Iodine-catalyzed electrophilic substitution of indoles: Synthesis of (un)symmetrical diindolylmethanes with a quaternary carbon center. Beilstein Journal of Organic Chemistry 2021, 17 , 1464-1475. https://doi.org/10.3762/bjoc.17.102
    27. Xi Yang, Jianwen Liu, Zongqing Huo, Huansha Yuwen, Yan Li, Yu Zhang. Fluevirines E and F, two new alkaloids from Flueggea virosa. Natural Product Research 2020, 34 (14) , 2001-2006. https://doi.org/10.1080/14786419.2019.1569661
    28. Helena Mannochio Russo, Emerson Ferreira Queiroz, Laurence Marcourt, Adriano Rutz, Pierre-Marie Allard, Rafael Felipe de Almeida, Nilton Marques Carvalho, Jean-Luc Wolfender, Vanderlan da Silva Bolzani. Phytochemical analysis of the methanolic leaves extract of Niedenzuella multiglandulosa (Malpighiaceae), a plant species toxic to cattle in Brazil. Phytochemistry Letters 2020, 37 , 10-16. https://doi.org/10.1016/j.phytol.2020.02.005
    29. Arvind Singh, Gurpreet Kaur, Bubun Banerjee. Recent Developments on the Synthesis of Biologically Significant bis/tris(indolyl)methanes under Various Reaction Conditions: A Review. Current Organic Chemistry 2020, 24 (6) , 583-621. https://doi.org/10.2174/1385272824666200228092752
    30. Arvind Singh, Gurpreet Kaur, Amninder Kaur, Vivek K. Gupta, Bubun Banerjee. A General Method for the Synthesis of 3,3-bis(indol-3-yl)indolin-2-ones, bis(indol-3-yl)(aryl)methanes and tris(indol-3-yl)methanes Using Naturally Occurring Mandelic Acid as an Efficient Organo-catalyst in Aqueous Ethanol at Room Temperature. Current Green Chemistry 2020, 7 (1) , 128-140. https://doi.org/10.2174/2213346107666200228125715
    31. Rana Chatterjee, Sougata Santra, Grigory V. Zyryanov, Adinath Majee. Brønsted acidic ionic liquid–catalyzed tandem trimerization of indoles: An efficient approach towards the synthesis of indole 3,3′‐trimers under solvent‐free conditions. Journal of Heterocyclic Chemistry 2020, 57 (4) , 1863-1874. https://doi.org/10.1002/jhet.3914
    32. Lulu Shao, Ping Wu, Liangxiong Xu, Jinghua Xue, Hanxiang Li, Xiaoyi Wei. Colletotryptins A–F, new dimeric tryptophol derivatives from the endophytic fungus Colletotrichum sp. SC1355. Fitoterapia 2020, 141 , 104465. https://doi.org/10.1016/j.fitote.2019.104465
    33. Xinxin Yuan, Lulu Wu, Cuilian Xu, Zhenliang Pan, Lijun Shi, Guoyu Yang, Caixia Wang, Sufang Fan. A consecutive one-pot two-step approach to novel trifluoromethyl-substituted bis(indolyl)methane derivatives promoted by Sc(OTf)3 and p-TSA. Tetrahedron Letters 2019, 60 (52) , 151329. https://doi.org/10.1016/j.tetlet.2019.151329
    34. Marilia Valli, Helena Mannochio Russo, Alan Cesar Pilon, Meri Emili Ferreira Pinto, Nathalia B. Dias, Rafael Teixeira Freire, Ian Castro-Gamboa, Vanderlan da Silva Bolzani. Computational methods for NMR and MS for structure elucidation II: database resources and advanced methods. Physical Sciences Reviews 2019, 4 (11) https://doi.org/10.1515/psr-2018-0167
    35. Priya Kamboj, Sunil Dutt, Sourav Chakroborty, Vikas Tyagi. CuI-catalyzed highly regioselective C H functionalization of indoles using indole-3-tosylhydrazones as carbene precursor: An efficient synthesis of 3,3-bis(indolyl)methane derivatives. Tetrahedron Letters 2019, 60 (43) , 151162. https://doi.org/10.1016/j.tetlet.2019.151162
    36. Marcelo R. Pace, Israel L. Cunha Neto, Leyde N. N. Santos‐Silva, Gladys F. A. Melo‐de‐Pinna, Pedro Acevedo‐Rodríguez, Rafael F. Almeida, André M. Amorim, Veronica Angyalossy. First report of laticifers in lianas of Malpighiaceae and their phylogenetic implications. American Journal of Botany 2019, 106 (9) , 1156-1172. https://doi.org/10.1002/ajb2.1350
    37. Lindon W. K. Moodie, Kristina Sepčić, Tom Turk, Robert Frangež, Johan Svenson. Natural cholinesterase inhibitors from marine organisms. Natural Product Reports 2019, 36 (8) , 1053-1092. https://doi.org/10.1039/C9NP00010K
    38. Alexey Koval, Constant A. Pieme, Emerson Ferreira Queiroz, Simone Ragusa, Kamal Ahmed, Artem Blagodatski, Jean-Luc Wolfender, Tatiana V. Petrova, Vladimir L. Katanaev. Tannins from Syzygium guineense suppress Wnt signaling and proliferation of Wnt-dependent tumors through a direct effect on secreted Wnts. Cancer Letters 2018, 435 , 110-120. https://doi.org/10.1016/j.canlet.2018.08.003
    39. MARILIA VALLI, HELENA M. RUSSO, VANDERLAN S. BOLZANI. The potential contribution of the natural products from Brazilian biodiversity to bioeconomy. Anais da Academia Brasileira de Ciências 2018, 90 (1 suppl 1) , 763-778. https://doi.org/10.1590/0001-3765201820170653
    40. André Luis de Alcantara Guimarães, Renato Pamplona Cardoso Costa, Lucio Mendes Cabral, Ana Cláudia de Macêdo Vieira. Comparative anatomy and chemical analysis of the vegetative organs of three species of Stigmaphyllon (Malpighiaceae). Flora 2016, 224 , 30-41. https://doi.org/10.1016/j.flora.2016.07.001
    41. Päivi Järvinen, Susanna Nybond, Laurence Marcourt, Emerson Ferreira Queiroz, Jean-Luc Wolfender, Aila Mettälä, Matti Karp, Heikki Vuorela, Pia Vuorela, Annele Hatakka, Päivi Tammela. Cell-based bioreporter assay coupled to HPLC micro-fractionation in the evaluation of antimicrobial properties of the basidiomycete fungus Pycnoporus cinnabarinus. Pharmaceutical Biology 2016, 54 (6) , 1108-1115. https://doi.org/10.3109/13880209.2015.1103754
    42. Elisabeth K. Olsen, Espen Hansen, Lindon W. K. Moodie, Johan Isaksson, Kristina Sepčić, Marija Cergolj, Johan Svenson, Jeanette H. Andersen. Marine AChE inhibitors isolated from Geodia barretti: natural compounds and their synthetic analogs. Organic & Biomolecular Chemistry 2016, 14 (5) , 1629-1640. https://doi.org/10.1039/C5OB02416A
    43. Hao Wen, Liang Wang, Lubin Xu, Zhihui Hao, Chang‐Lun Shao, Chang‐Yun Wang, Jian Xiao. Fluorinated Alcohol‐Mediated S N 1‐Type Reaction of Indolyl Alcohols with Diverse Nucleophiles. Advanced Synthesis & Catalysis 2015, 357 (18) , 4023-4030. https://doi.org/10.1002/adsc.201500500
    44. Jiun‐Le Shih, Thien S. Nguyen, Jeremy A. May. Organocatalyzed Asymmetric Conjugate Addition of Heteroaryl and Aryl Trifluoroborates: a Synthetic Strategy for Discoipyrrole D. Angewandte Chemie 2015, 127 (34) , 10069-10073. https://doi.org/10.1002/ange.201503528
    45. Jiun‐Le Shih, Thien S. Nguyen, Jeremy A. May. Organocatalyzed Asymmetric Conjugate Addition of Heteroaryl and Aryl Trifluoroborates: a Synthetic Strategy for Discoipyrrole D. Angewandte Chemie International Edition 2015, 54 (34) , 9931-9935. https://doi.org/10.1002/anie.201503528
    46. M. M. F. Queiroz, G. Marti, E. F. Queiroz, L. Marcourt, I. Castro-Gamboa, V. S. Bolzani, J.-L. Wolfender. LC-MS/MS Quantitative Determination of Tetrapterys mucronata Alkaloids, a Plant Occasionally used in Ayahuasca Preparation. Phytochemical Analysis 2015, 26 (3) , 183-188. https://doi.org/10.1002/pca.2548
    47. Xiao‐Xue Sun, Bai‐Xiang Du, Hong‐Hao Zhang, Lei Ji, Feng Shi. Catalytic Asymmetric Arylation of 3‐Indolylmethanols: Enantioselective Synthesis of 3,3′‐Bis(indolyl)oxindoles with High Atom Economy. ChemCatChem 2015, 7 (7) , 1211-1221. https://doi.org/10.1002/cctc.201500093
    48. Jian Lin Li, Lei Huang, Juan Liu, Yan Song, Jie Gao, Jee H. Jung, Yonghong Liu, Guangtong Chen. Acetylcholinesterase inhibitory dimeric indole derivatives from the marine actinomycetes Rubrobacter radiotolerans. Fitoterapia 2015, 102 , 203-207. https://doi.org/10.1016/j.fitote.2015.01.014
    49. M.M.F. Queiroz, E.F. Queiroz, M.L. Zeraik, G. Marti, Q. Favre-Godal, C. Simões-Pires, L. Marcourt, P.A. Carrupt, M. Cuendet, M.Q. Paulo, V.S. Bolzani, J.L. Wolfender. Antifungals and acetylcholinesterase inhibitors from the stem bark of Croton heliotropiifolius. Phytochemistry Letters 2014, 10 , lxxxviii-xciii. https://doi.org/10.1016/j.phytol.2014.08.013
    50. Vanessa Chapla, Maria Zeraik, Ioanis Leptokarydis, Geraldo Silva, Vanderlan Bolzani, Maria Young, Ludwig Pfenning, Angela Araújo. Antifungal Compounds Produced by Colletotrichum gloeosporioides, an Endophytic Fungus from Michelia champaca. Molecules 2014, 19 (11) , 19243-19252. https://doi.org/10.3390/molecules191119243
    51. Suman Kr Ghosh, Rajagopal Nagarajan. Total synthesis of cruciferane via epoxidation/tandem cyclization sequence. RSC Adv. 2014, 4 (108) , 63147-63149. https://doi.org/10.1039/C4RA10309B

    Journal of Natural Products

    Cite this: J. Nat. Prod. 2014, 77, 3, 650–656
    Click to copy citationCitation copied!
    https://doi.org/10.1021/np401003p
    Published February 12, 2014
    Copyright © 2014 The American Chemical Society and American Society of Pharmacognosy

    Article Views

    2235

    Altmetric

    -

    Citations

    Learn about these metrics

    Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.

    Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.

    The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.