{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,14]],"date-time":"2026-04-14T12:49:35Z","timestamp":1776170975654,"version":"3.50.1"},"reference-count":59,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,4,14]],"date-time":"2026-04-14T00:00:00Z","timestamp":1776124800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Drug Discov."],"abstract":"<jats:p>\n                    The Zika virus (ZIKV) is an\n                    <jats:italic>Orthoflavivirus<\/jats:italic>\n                    linked to several neurological and developmental diseases, and it remains a significant global health concern for which no treatments or vaccines are currently available. In this study, we optimized the malachite green colorimetric assay, previously used to measure the RNA-dependent RNA polymerase (RdRp) activity of the hepatitis C and foot-and-mouth disease viruses, and applied this assay for the preliminary identification of the ZIKV RdRp modulators. RdRp is an enzyme essential for viral replication. Modulator screening was conducted using 204 compounds from the Natural Product Set IV of the National Cancer Institute Developmental Therapeutics Program. We identified two compounds, purpurogallin and digallic acid, as preliminary modulators of the ZIKV RdRp. Future studies will validate these preliminary hits using orthogonal assays, perform dose-response analyses, and elucidate their mechanisms of action.\n                  <\/jats:p>","DOI":"10.3389\/fddsv.2026.1749327","type":"journal-article","created":{"date-parts":[[2026,4,14]],"date-time":"2026-04-14T11:57:06Z","timestamp":1776167826000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Optimization of a malachite green\u2013pyrophosphatase assay for the Zika virus RNA-dependent RNA polymerase and preliminary identification of natural product modulators"],"prefix":"10.3389","volume":"6","author":[{"given":"Vanessa","family":"Aitken","sequence":"first","affiliation":[{"name":"Department of Chemistry and Biochemistry, The University of Texas at El Paso","place":["El Paso, TX, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anthony F. T.","family":"Moore","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Central Florida","place":["Orlando, FL, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manuel","family":"Terrazas-L\u00f3pez","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry, The University of Texas at El Paso","place":["El Paso, TX, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Salvador","family":"Rodarte","sequence":"additional","affiliation":[{"name":"Computational Sciences Program, The University of Texas at El Paso","place":["El Paso, TX, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eda","family":"Koculi","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry, The University of Texas at El Paso","place":["El Paso, TX, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,4,14]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"e202200301","DOI":"10.1002\/cmdc.202200301","article-title":"Potent inhibition of bacterial DNA gyrase by digallic acid and other gallate derivatives","volume":"17","author":"Alfonso","year":"2022","journal-title":"ChemMedChem"},{"key":"B2","doi-asserted-by":"publisher","first-page":"118","DOI":"10.1039\/b711474e","article-title":"A fresh look at natural tropolonoids","volume":"25","author":"Bentley","year":"2008","journal-title":"Nat. Prod. Rep."},{"key":"B3","doi-asserted-by":"publisher","first-page":"509","DOI":"10.1016\/j.tiv.2009.06.024","article-title":"Study of genotoxic, antigenotoxic and antioxidant activities of the digallic acid isolated from Pistacia lentiscus fruits","volume":"24","author":"Bhouri","year":"2010","journal-title":"Toxicol Vitro"},{"key":"B4","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.pep.2005.03.016","article-title":"SUMO fusion technology for difficult-to-express proteins","volume":"43","author":"Butt","year":"2005","journal-title":"Protein Expr. Purif."},{"key":"B5","doi-asserted-by":"publisher","first-page":"e0141283","DOI":"10.1371\/journal.pone.0141283","article-title":"Effects of small molecule calcium-activated chloride channel inhibitors on structure and function of accessory cholera enterotoxin (ace) of Vibrio cholerae","volume":"10","author":"Chatterjee","year":"2015","journal-title":"PLoS One"},{"key":"B6","doi-asserted-by":"publisher","first-page":"408","DOI":"10.1261\/rna.052928.115","article-title":"The DbpA catalytic core unwinds double-helix substrates by directly loading on them","volume":"22","author":"Childs","year":"2016","journal-title":"RNA"},{"key":"B7","doi-asserted-by":"publisher","first-page":"111368","DOI":"10.1016\/j.intimp.2023.111368","article-title":"Zika virus: antiviral immune response, inflammation, and cardiotonic steroids as antiviral agents","volume":"127","author":"de Sales-Neto","year":"2024","journal-title":"Int. Immunopharmacol."},{"key":"B8","doi-asserted-by":"publisher","first-page":"257","DOI":"10.1515\/revac.2006.25.4.257","article-title":"Potentiometric and spectrophotometric studies of the mixed-ligand complexes of quercetin and digallic acid with Iron(II) and Magnesium(II)","volume":"25","author":"Erdogan","year":"2006","journal-title":"Rev. Anal. Chem."},{"key":"B9","doi-asserted-by":"publisher","first-page":"105194","DOI":"10.1016\/j.antiviral.2021.105194","article-title":"Optimal flexibility of the linker region of zika virus NS5 methyltransferase-polymerase is critical for virus replication","volume":"195","author":"Flory","year":"2021","journal-title":"Antivir. Res."},{"key":"B10","doi-asserted-by":"publisher","first-page":"100315","DOI":"10.1016\/j.xpro.2021.100315","article-title":"Efficient purification and assembly of ribonucleoprotein complex for interaction analysis by MST assay coupled with GaMD simulations","volume":"2","author":"Gao","year":"2021","journal-title":"Star. Protoc."},{"key":"B11","doi-asserted-by":"publisher","first-page":"181","DOI":"10.1146\/annurev-pathmechdis-031521-034739","article-title":"Pathogenesis of zika virus infection","volume":"18","author":"Giraldo","year":"2023","journal-title":"Annu. Rev. Pathol."},{"key":"B12","doi-asserted-by":"publisher","first-page":"3432","DOI":"10.1093\/jac\/dkw340","article-title":"Identification of inhibitors for single-stranded DNA-Binding proteins in eubacteria","volume":"71","author":"Glanzer","year":"2016","journal-title":"J. Antimicrob. Chemother."},{"key":"B13","doi-asserted-by":"publisher","first-page":"14764","DOI":"10.1038\/ncomms14764","article-title":"Crystal structure of zika virus NS5 RNA-Dependent RNA polymerase","volume":"8","author":"Godoy","year":"2017","journal-title":"Nat. Commun."},{"key":"B14","doi-asserted-by":"publisher","first-page":"247","DOI":"10.1177\/1087057105285610","article-title":"A comparison of assay performance measures in screening assays: signal window, Z' factor, and assay variability ratio","volume":"11","author":"Iversen","year":"2006","journal-title":"J. Biomol. Screen"},{"key":"B15","doi-asserted-by":"publisher","first-page":"10674","DOI":"10.1074\/jbc.M111.325530","article-title":"Assembly, purification, and pre-steady-state kinetic analysis of active RNA-Dependent RNA polymerase elongation complex","volume":"287","author":"Jin","year":"2012","journal-title":"J. Biol. Chem."},{"key":"B16","doi-asserted-by":"publisher","first-page":"27","DOI":"10.1038\/s44298-025-00110-3","article-title":"Effects of oxidative stress on viral infections: an overview","volume":"3","author":"Kayesh","year":"2025","journal-title":"Npj Viruses"},{"key":"B17","doi-asserted-by":"publisher","first-page":"200","DOI":"10.5483\/BMBRep.2012.45.3.200","article-title":"Anti-inflammatory functions of purpurogallin in LPS-Activated human endothelial cells","volume":"45","author":"Kim","year":"2012","journal-title":"BMB Rep."},{"key":"B18","doi-asserted-by":"publisher","first-page":"376","DOI":"10.5483\/bmbrep.2014.47.7.195","article-title":"Antiplatelet and antithrombotic activities of purpurogallin in vitro and in vivo","volume":"47","author":"Ku","year":"2014","journal-title":"BMB Rep."},{"key":"B19","doi-asserted-by":"publisher","first-page":"519","DOI":"10.1007\/s13765-013-3169-7","article-title":"Inhibitory effects of purpurogallin on the endothelial protein C receptor shedding in vitro and in vivo","volume":"56","author":"Ku","year":"2013","journal-title":"J. Korean Soc. Appl. Biol. Chem."},{"key":"B20","article-title":"Advancement of phenolic acids in drug discovery: fundamentals and applications","author":"Kumar","year":"2024"},{"key":"B21","doi-asserted-by":"publisher","first-page":"247","DOI":"10.1016\/j.ab.2003.10.034","article-title":"A continuous nonradioactive assay for RNA-Dependent RNA polymerase activity","volume":"325","author":"Lahser","year":"2004","journal-title":"Anal. Biochem."},{"key":"B22","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.01967-16","article-title":"Analysis of ribonucleotide 5'-Triphosphate analogs as potential inhibitors of zika virus RNA-dependent RNA polymerase by using nonradioactive polymerase assays","volume":"61","author":"Lu","year":"2017","journal-title":"Antimicrob. Agents Chemother."},{"key":"B23","doi-asserted-by":"publisher","first-page":"e23001","DOI":"10.1002\/bip.23001","article-title":"DbpA is a region-specific RNA helicase","volume":"107","author":"Moore","year":"2017","journal-title":"Biopolymers"},{"key":"B24","doi-asserted-by":"publisher","first-page":"12640","DOI":"10.1021\/acsomega.1c00700","article-title":"Interactions of the C-Terminal truncated DEAD-box protein DDX3X with RNA and nucleotide substrates","volume":"6","author":"Moore","year":"2021","journal-title":"ACS Omega"},{"key":"B25","doi-asserted-by":"publisher","first-page":"2598","DOI":"10.1021\/acsomega.4c07522","article-title":"Substrate specificities of DDX1: a human DEAD-box protein","volume":"10","author":"Moore","year":"2025","journal-title":"ACS Omega"},{"key":"B26","doi-asserted-by":"publisher","first-page":"1234","DOI":"10.1021\/np50071a015","article-title":"Differential inhibition of reverse transcriptase and various DNA polymerases by digallic acid and its derivatives","volume":"53","author":"Nakane","year":"1990","journal-title":"J. Nat. Prod."},{"key":"B27","doi-asserted-by":"publisher","first-page":"2365","DOI":"10.1074\/jbc.M110.175109","article-title":"TMEM16A inhibitors reveal TMEM16A as a minor component of calcium-activated chloride channel conductance in airway and intestinal epithelial cells","volume":"286","author":"Namkung","year":"2011","journal-title":"J. Biol. Chem."},{"key":"B28","doi-asserted-by":"publisher","first-page":"284","DOI":"10.1016\/j.ab.2012.11.019","article-title":"An efficient colorimetric assay for RNA synthesis by viral RNA-Dependent RNA polymerases, using thermostable pyrophosphatase","volume":"434","author":"Nguyen","year":"2013","journal-title":"Anal. Biochem."},{"key":"B29","doi-asserted-by":"publisher","first-page":"211","DOI":"10.1016\/s0166-0934(01)00443-8","article-title":"A nonisotopic assay method for hepatitis C virus NS5B polymerase","volume":"101","author":"Park","year":"2002","journal-title":"J. Virol. Methods"},{"key":"B30","doi-asserted-by":"publisher","first-page":"1171","DOI":"10.3892\/ijmm.2013.1478","article-title":"Purpurogallin exerts anti-inflammatory effects in lipopolysaccharide-stimulated BV2 microglial cells through the inactivation of the NF-kappaB and MAPK signaling pathways","volume":"32","author":"Park","year":"2013","journal-title":"Int. J. Mol. Med."},{"key":"B31","doi-asserted-by":"publisher","first-page":"100180","DOI":"10.1016\/j.microb.2024.100180","article-title":"The role of microglia in zika virus pathogenesis: possible diagnostic and therapeutic strategies","volume":"5","author":"Paul","year":"2024","journal-title":"Microbe"},{"key":"B32","doi-asserted-by":"publisher","first-page":"224","DOI":"10.1007\/s00705-023-05835-1","article-title":"Renaming of the genus flavivirus to orthoflavivirus and extension of binomial species names within the family flaviviridae","volume":"168","author":"Postler","year":"2023","journal-title":"Arch. Virol."},{"key":"B33","doi-asserted-by":"publisher","first-page":"27","DOI":"10.1007\/BF00944200","article-title":"Purpurogallin, a scavenger of polymorphonuclear leukocyte-derived oxyradicals","volume":"139","author":"Prasad","year":"1994","journal-title":"Mol. Cell Biochem."},{"key":"B34","doi-asserted-by":"publisher","first-page":"88","DOI":"10.1080\/00031305.1994.10476030","article-title":"The three sigma rule","volume":"48","author":"Pukelsheim","year":"1994","journal-title":"Am. Statistician"},{"key":"B35","doi-asserted-by":"publisher","first-page":"1026","DOI":"10.4269\/ajtmh.24-0420","article-title":"A review of the recent epidemiology of zika virus infection","volume":"112","author":"Rabe","year":"2025","journal-title":"Am. J. Trop. Med. Hyg."},{"key":"B36","doi-asserted-by":"publisher","first-page":"1612","DOI":"10.3390\/antiox12081612","article-title":"Unlocking the antibiofilm potential of natural compounds by targeting the NADH:quinone oxidoreductase WrbA","volume":"12","author":"Ratti","year":"2023","journal-title":"Antioxidants (Basel)"},{"key":"B37","doi-asserted-by":"publisher","first-page":"316","DOI":"10.3934\/Neuroscience.2019.4.316","article-title":"Elucidating the novel biomarker and therapeutic potentials of high-mobility group box 1 in subarachnoid hemorrhage: a review","volume":"6","author":"Richard","year":"2019","journal-title":"AIMS Neurosci."},{"key":"B38","doi-asserted-by":"publisher","first-page":"823619","DOI":"10.4061\/2011\/823619","article-title":"Novel strategies for upstream and downstream processing of tannin acyl hydrolase","volume":"2011","author":"Rodriguez-Duran","year":"2011","journal-title":"Enzyme Res."},{"key":"B39","doi-asserted-by":"publisher","first-page":"2715","DOI":"10.1093\/nar\/29.13.2715","article-title":"Primer-dependent synthesis by poliovirus RNA-Dependent RNA polymerase (3D(pol))","volume":"29","author":"Rodriguez-Wells","year":"2001","journal-title":"Nucleic Acids Res."},{"key":"B40","doi-asserted-by":"publisher","first-page":"e0007213","DOI":"10.1371\/journal.pntd.0007213","article-title":"Global expansion and redistribution of Aedes-borne virus transmission risk with climate change","volume":"13","author":"Ryan","year":"2019","journal-title":"PLoS Negl. Trop. Dis."},{"key":"B41","doi-asserted-by":"publisher","first-page":"84","DOI":"10.1111\/gcb.15384","article-title":"Warming temperatures could expose more than 1.3 billion new people to zika virus risk by 2050","volume":"27","author":"Ryan","year":"2021","journal-title":"Glob. Chang. Biol."},{"key":"B42","doi-asserted-by":"publisher","first-page":"559","DOI":"10.3390\/v10100559","article-title":"Role of host cell secretory machinery in zika virus life cycle","volume":"10","author":"Sager","year":"2018","journal-title":"Viruses"},{"key":"B43","doi-asserted-by":"publisher","first-page":"196","DOI":"10.1016\/0003-2697(73)90184-x","article-title":"Investigation of methods for measurement of radioactivity in tritiated DNA and applications to assays for DNA polymerase activity","volume":"56","author":"Schrier","year":"1973","journal-title":"Anal. Biochem."},{"key":"B44","doi-asserted-by":"publisher","first-page":"1462","DOI":"10.1073\/pnas.61.4.1462","article-title":"RNA polymerase activity in purified reoviruses","volume":"61","author":"Shatkin","year":"1968","journal-title":"Proc. Natl. Acad. Sci. U. S. A."},{"key":"B45","doi-asserted-by":"publisher","first-page":"2012","DOI":"10.1128\/JVI.01606-06","article-title":"Foot-and-mouth disease virus mutant with decreased sensitivity to ribavirin: implications for error catastrophe","volume":"81","author":"Sierra","year":"2007","journal-title":"J. Virol."},{"key":"B46","doi-asserted-by":"publisher","first-page":"S935","DOI":"10.1093\/infdis\/jix515","article-title":"Zika virus structure, maturation, and receptors","volume":"216","author":"Sirohi","year":"2017","journal-title":"J. Infect. Dis."},{"key":"B47","doi-asserted-by":"publisher","first-page":"e22198","DOI":"10.1096\/fj.202101708RR","article-title":"Allosteric differences dictate GroEL complementation of E. coli","volume":"36","author":"Sivinski","year":"2022","journal-title":"FASEB J."},{"key":"B48","doi-asserted-by":"publisher","first-page":"312","DOI":"10.3389\/fchem.2020.00312","article-title":"A new family of jumonji C domain-containing KDM inhibitors inspired by natural product purpurogallin","volume":"8","author":"Souto","year":"2020","journal-title":"Front. Chem."},{"key":"B49","doi-asserted-by":"publisher","first-page":"7438","DOI":"10.1074\/jbc.M113.542324","article-title":"Functional swapping between transmembrane proteins TMEM16A and TMEM16F","volume":"289","author":"Suzuki","year":"2014","journal-title":"J. Biol. Chem."},{"key":"B50","doi-asserted-by":"publisher","first-page":"4082","DOI":"10.1016\/j.bmcl.2017.07.045","article-title":"ATP-competitive, marine derived natural products that target the DEAD box helicase, eIF4A","volume":"27","author":"Tillotson","year":"2017","journal-title":"Bioorg Med. Chem. Lett."},{"key":"B51","doi-asserted-by":"publisher","first-page":"45","DOI":"10.1016\/0003-2697(87)90649-x","article-title":"Inorganic and organic phosphate measurements in the nanomolar range","volume":"161","author":"Van Veldhoven","year":"1987","journal-title":"Anal. Biochem."},{"key":"B52","doi-asserted-by":"publisher","first-page":"187","DOI":"10.1016\/j.mex.2014.08.007","article-title":"Comparative analysis and validation of the malachite green assay for the high throughput biochemical characterization of terpene synthases","volume":"1","author":"Vardakou","year":"2014","journal-title":"MethodsX"},{"key":"B53","doi-asserted-by":"publisher","first-page":"429","DOI":"10.1006\/viro.2000.0492","article-title":"Exploiting polymerase promiscuity: a simple colorimetric RNA polymerase assay","volume":"274","author":"Vassiliou","year":"2000","journal-title":"Virology"},{"key":"B54","doi-asserted-by":"publisher","first-page":"181","DOI":"10.1002\/bscb.19830920212","article-title":"Digallic acid","volume":"92","author":"Verzele","year":"1983","journal-title":"Bull. Des. Soci\u00e9t\u00e9s Chim. Belg."},{"key":"B55","doi-asserted-by":"publisher","first-page":"3696","DOI":"10.1128\/jb.169.8.3696-3700.1987","article-title":"Kinetics and inhibition studies of catechol O-methyltransferase from the yeast Candida tropicalis","volume":"169","author":"Veser","year":"1987","journal-title":"J. Bacteriol."},{"key":"B56","doi-asserted-by":"publisher","first-page":"189","DOI":"10.1016\/S0076-6879(09)69009-1","article-title":"Analysis of RNA folding by native polyacrylamide gel electrophoresis","volume":"469","author":"Woodson","year":"2009","journal-title":"Methods Enzymol."},{"key":"B57","doi-asserted-by":"publisher","first-page":"e23172","DOI":"10.1371\/journal.pone.0023172","article-title":"Phosphatase-coupled universal kinase assay and kinetics for first-order-rate coupling reaction","volume":"6","author":"Wu","year":"2011","journal-title":"PLoS One"},{"key":"B58","doi-asserted-by":"publisher","first-page":"395","DOI":"10.4062\/biomolther.2018.151","article-title":"Purpurogallin protects keratinocytes from damage and apoptosis induced by ultraviolet B radiation and particulate matter 2.5","volume":"27","author":"Zhen","year":"2019","journal-title":"Biomol. Ther. Seoul."},{"key":"B59","doi-asserted-by":"publisher","first-page":"107381","DOI":"10.1016\/j.bioorg.2024.107381","article-title":"Discovery of digallic acid as XOD\/URAT1 dual target inhibitor for the treatment of hyperuricemia","volume":"147","author":"Zheng","year":"2024","journal-title":"Bioorg Chem."}],"container-title":["Frontiers in Drug Discovery"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fddsv.2026.1749327\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,14]],"date-time":"2026-04-14T11:57:08Z","timestamp":1776167828000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fddsv.2026.1749327\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,14]]},"references-count":59,"alternative-id":["10.3389\/fddsv.2026.1749327"],"URL":"https:\/\/doi.org\/10.3389\/fddsv.2026.1749327","relation":{},"ISSN":["2674-0338"],"issn-type":[{"value":"2674-0338","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,14]]},"article-number":"1749327"}}