Synthesis, Purification, Characterization, and ABTS Antioxidant Evaluation of Novel Azo Dyes
Jeremy A. Rodríguez-Vargas, Sebastián H. Díaz-Rodríguez, Víctor G. Vergara-Rodríguez, Ángel Vidal-Rosado, Cristtian Rivera-Torres, Alejandra Ríos-Rodríguez, Martín Rodríguez-Del Valle, Daliana Agosto-Disdier, Marielys Torres-Díaz, Kai H. Griebenow, Raúl R. Rodríguez-Berríos
Organics · pp. 39–39 · Published 2 Sep 2025
10.3390/org6030039Abstract
The search for bioactive compounds with antioxidant properties is critical in combating oxidative stress-related diseases and advancing novel therapeutic agents. Azo dyes, traditionally used in textiles, food, and cosmetics, have recently attracted attention due to their emerging biological activities, including antioxidant potential. In this study, we synthesized and characterized 267 azo dyes derived from natural phenolic cores such as salicylic acid, syringol, and 5,6,7,8-tetrahydro-2-naphthol. Eighteen of these compounds are novel. Structural characterization was performed using NMR, UV-Vis, IR spectroscopy, and mass spectrometry. Antioxidant activity was assessed using in vitro assays with ABTS radical scavenging method. SAR analysis revealed that dyes derived from syringol and 5, 6, 7, 8-tetrahydro-2-naphthol showed the most consistent and potent antioxidant activity. Notably, azo dyes bearing fluoro and nitro substituents in the para position exhibited the lowest IC50 values, highlighting the influence of electron-withdrawing groups and substitution patterns on antioxidant behavior. This work establishes a precedent for SAR-driven evaluation of azo dyes using ABTS and supports their further exploration as functional antioxidant agents in medicinal chemistry.
References (83)
- 1 Bafana, 2011, Azo Dyes: Past, Present and the Future [DOI]
- 2 Aljamali, 2015, Review in Azo Compounds and Its Biological Activity [DOI]
- 3 Gürses, A., Açıkyıldız, M., Güneş, K., and Gürses, M.S. (2016). Classification of Dye and Pigments. Dyes and Pigments, Springer International Publishing. SpringerBriefs in Molecular Science. [DOI]
- 4 Crespi, 2019, Heteroaryl Azo Dyes as Molecular Photoswitches [DOI]
- 5 Shindy, 2016, Basics in Colors, Dyes and Pigments Chemistry: A Review
- 6 Gung, 2004, Parallel Combinatorial Synthesis of Azo Dyes: A Combinatorial Experiment Suitable for Undergraduate Laboratories [DOI]
- 7 Alsantali, 2022, Miscellaneous Azo Dyes: A Comprehensive Review on Recent Advancements in Biological and Industrial Applications [DOI]
- 8 Decelles, 1949, The Story of Dyes and Dyeing [DOI]
- 9 Benkhaya, 2020, Classifications, Properties, Recent Synthesis and Applications of Azo Dyes [DOI]
- 10 Ahmad, 2012, Synthesis and Applications of Three Vinylsulfone Based Fiber-Reactive Azo Dyes for Dyeing Cotton Fabric
- 11 Barciela, 2023, Azo Dyes in the Food Industry: Features, Classification, Toxicity, Alternatives, and Regulation [DOI]
- 12 Sabnis, R.W. (2007). Handbook of Acid-Base Indicators, CRC Press. [DOI]
- 13 Khanum, 2023, Recent Review on Synthesis, Spectral Studies, Versatile Applications of Azo Dyes and Its Metal Complexes [DOI]
- 14 Ube, 2025, Sunlight-Driven Photomobile Polymer Materials Containing Push–Pull Azobenzene Moieties [DOI]
- 15 Al-Khuzaie, M.G.A., and Al-Majidi, S.M.H. (2020). Synthesis and Characterization of New Azo Compounds Linked to 1,8-Naphthalimide as New Fluorescent Dispersed Dyes for Cotton Fibers, IOP Publishing. [DOI]
- 16 Sahoo, 2016, Medicinal Interest of Azo-Based Organic Compounds: A Review
- 17 Vidule, 2013, Synthesis and Antimicrobial Studies of Few New Substituted 2-Methyl-3-(Aryldiazenyl) Pyrazolo[5,1-b]Quinazolin-9(3H)-One
- 18 Mistry, 2011, Synthesis of Some Heterocyclic Compounds and Studies of Their Antimicrobial Efficacy
- 19 Hawaiz, 2014, Synthesis and Antibacterial Evaluation of Some New Azo-Pyrazoline Compounds Derived From p-Aminoacetophenone
- 20 Addnan, 2016, Synthesis and Characterization of New Azo Dye (1-(4-Sulfonyl Phenyl Azo)-2-(7-Chloro-4-[{4-(Diethyl Amino)-1-Methyl Butyl} Amino] Quindine from Chloroquine Diphosphate and Study Antibacterial Activity [DOI]
- 21 Ali, 2019, DNA Binding Three Azo Dyes as New Antibiotics [DOI]
- 22 Kantar, 2018, Some Azo Dyes Containing Eugenol and Guaiacol, Synthesis, Antioxidant Capacity, Urease Inhibitory Properties and Anti-Helicobacter Pylori Activity
- 23 Karthika, 2015, Synthesis and Characterization of Azo Compounds Containing O-Cresol and Beta-Naphthol Moieties and Study of Antimicrobial Activity
- 24 2012, Azo Dyes–Biological Activity and Synthetic Strategy
- 25 Nofal, 2011, Synthesis of New Pyrimidine Derivatives with Evaluation of Their Anti-Inflammatory and Analgesic Activities
- 26 Berghot, 2014, Synthesis, Antioxidant and Cytotoxic Activities of Novel Naphthoquinone Derivatives from 2, 3-Dihydro-2, 3-Epoxy-1, 4-Naphthoquinone
- 27 Abouzayed, 2021, Synthesis of Some Novel Nanosized Chelates of Anchoring Bisazo Dye 5-[5-(4,6-Dioxo-2-Thioxo-Hexahydro-Pyrimidin-5-Ylazo)-Naphthalen-1-Ylazo]-2-Mercapto-1H-Pyrimidine-4,6-Dione and Their Applications as Antioxidant and Antitumor Agents [DOI]
- 28 Bae, 2013, A Novel Synthesized Tyrosinase Inhibitor:(E)-2-((2, 4-Dihydroxyphenyl) Diazenyl) Phenyl 4-Methylbenzenesulfonate as an Azo-Resveratrol Analog [DOI]
- 29 Fuchs, 2024, Investigation of the Inhibitory Properties of Azo-Dyes on Chorismate Synthase from Paracoccidioides brasiliensis [DOI]
- 30 Marinescu, M., Popa, C.V., Tănase, M.A., Soare, A.C., Tablet, C., Bala, D., Cinteza, L.O., Diţu, L.M., Gifu, I.C., and Petcu, C. (2022). Synthesis, Characterization, DFT Study and Antifungal Activities of Some Novel 2-(Phenyldiazenyl)Phenol Based Azo Dyes. Materials, 15. [DOI]
- 31 Ahmad, 2015, Preparation and Characterization of Some New Azo Dyes, Azomethine Dyes and Heterocyclic -Schiff Bases Derivatives
- 32 Naik, 2012, Click Chemistry Approach for Bis-chromenyl Triazole Hybrids and Their Antitubercular Activity [DOI]
- 33 Cox, 2019, The Mutagenic Activity of Select Azo Compounds in MutaMouse Target Tissues in Vivo and Primary Hepatocytes in Vitro [DOI]
- 34 Mutar, 2025, Synthesis and Characterization of New (Au, Ru, and Rh) Ion Complexes and Evaluating Their Activity as Anticancer and Antioxidants [DOI]
- 35 Farghaly, 2008, Synthesis, Azo-Hydrazone Tautomerism and Antitumor Screening of N-(3-Ethoxycarbonyl-4, 5, 6, 7-Tetrahydro-Benzo [b] Thien-2-Yl)-2-Arylhydrazono-3-Oxobutanamide Derivatives
- 36 Sheldon, 2016, Photoswitchable Anticancer Activity via Trans–Cis Isomerization of a Combretastatin A-4 Analog [DOI]
- 37 Beale, J.M., and Block, J.H. (2022). Wilson and Gisvold’s Textbook of Organic Medicinal and Pharmaceutical Chemistry, Kaufman Press Exclusive. [12th ed.].
- 38 Khan, 2021, Recent Applications of Azo Dyes: A Paradigm Shift from Medicinal Chemistry to Biomedical Sciences [DOI]
- 39 Chung, 2016, Azo Dyes and Human Health: A Review [DOI]
- 40 Badnjevic, 2020, Toxicity of Azo Dyes in Pharmaceutical Industry [DOI]
- 41 Smith, J.G. (2020). Organic Chemistry, McGraw-Hill Education. [6th ed.].
- 42 Zhao, M.-Y., Tang, Y.-F., and Han, G.-Z. (2023). Recent Advances in the Synthesis of Aromatic Azo Compounds. Molecules, 28. [DOI]
- 43 2015, The Beneficial Biological Properties of Salicylic Acid [DOI]
- 44 Patil, 2015, The Azo Derivatives of Salicylic Acid
- 45 Ma, 2014, A Convenient Protocol for the Synthesis of 2-(2′-Hydroxy-5′-carboxyphenyl)-2H-benzotriazole to Avoid Decarboxylation When Using p-Hydroxybenzoic Acid as Coupling Component [DOI]
- 46 Yatsenko, 2014, Syn and Anti Conformations in 2-Hy-droxy-5-[(E)-(4-Nitro-phen-yl)Diazen-yl]Benzoic Acid and Two Related Salts [DOI]
- 47 Ibrahim, 2020, Synthesis and Evaluation of Biological Activity of Some Newsalicylic Acid Derivatives
- 48 Harveer, 2014, Synthesis, Characterization and Radical Scavenging Activity of Aromatic Amine Conjugates of 5-Aminosalicylic Acid [DOI]
- 49 Yang, J.-F., Yang, C.-H., Liang, M.-T., Gao, Z.-J., Wu, Y.-W., and Chuang, L.-Y. (2016). Chemical Composition, Antioxidant, and Antibacterial Activity of Wood Vinegar from Litchi Chinensis. Molecules, 21. [DOI]
- 50 Loo, 2008, Antioxidant Activity of Compounds Isolated from the Pyroligneous Acid, Rhizophora Apiculata [DOI]
- 51 Sánchez-Hernández, E., Teixeira, A., Pereira, C., Cruz, A., Martín-Gil, J., Oliveira, R., and Martín-Ramos, P. (2023). Chemical Constituents and Antimicrobial Activity of a Ganoderma lucidum (Curtis.) P. Karst. Aqueous Ammonia Extract. Plants, 12. [DOI]
- 52 Witasari, 2022, Antimicrobial Activities of Fungus Comb Extracts Isolated from Indomalayan Termite (Macrotermes gilvus Hagen) Mound [DOI]
- 53 Jacques, 1979, A New Aspect of Azo-Hydrazone Tautomerism [DOI]
- 54 Martins, 2001, Biodegradation of Bioaccessible Textile Azo Dyes by Phanerochaete chrysosporium [DOI]
- 55 Martins, 2002, Relationship of Chemical Structures of Textile Dyes on the Pre-Adaptation Medium and the Potentialities of Their Biodegradation by Phanerochaete chrysosporium [DOI]
- 56 (2000). Azo Dyes. Kirk-Othmer Encyclopedia of Chemical Technology, Wiley.
- 57 Kaul, 1965, Structures of Azoic Coupling Components and Azoic Dyes [DOI]
- 58 Ajani, 2013, Synthesis and Spectroscopic Study of Naphtholic and Phenolic Azo Dyes
- 59 Naik, 2001, Synthesis of Azo Dyes Based on A-Naphthol-Formaldehyde Oligomer and Their Application on Textile Fibres
- 60 Mhessn, 2012, Synthesis and Characterization of Azo Dye Para Red and New Derivatives [DOI]
- 61 Aziz, 2009, Optical Properties of Azo Dye (1-Phenylazo-2-Naphthol) Thin Films [DOI]
- 62 Baik, 1999, Photostimulated Reductive Cyclization of O-Nitrophenylazo Dyes Using Sodium Hydroxide in Isopropyl Alcohol. A New Synthesis of 2-Aryl-2H-Benzotriazoles [DOI]
- 63 Crump, 1963, The Paper Chromatographic Separation and Identification of Simple Phenols [DOI]
- 64 Crump, 1964, Thin Layer Chromatographic Analysis of Simple Alkyl Phenols [DOI]
- 65 Tsukahara, 1990, Molecular design of surface active polymeric UV-stabilizers by graft copolymers [DOI]
- 66 Salman, 2019, Antioxidant Activity of Some Newly Prepared Symmetrically Azo Dyes Derived from Sulfa Drugs
- 67 Salimi, 2019, Synthesis, Antioxidant and Antibacterial Activity of Azo Dye-Stilbene Hybrid Compounds [DOI]
- 68 Qamar, 2019, Synthesis, Structural Characterization, DNA Binding and Antioxidant Studies of 4,4′-Nitrophenoxyaniline Derived Azo Dyes [DOI]
- 69 2019, New Azo-Azomethine Derivative of Sulfanilamide: Synthesis, Characterization, Spectroscopic, Antimicrobial and Antioxidant Activity Study [DOI]
- 70 Unnisa, 2020, Design, Synthesis, Characterization, Computational Study and in-Vitro Antioxidant and Anti-Inflammatory Activities of Few Novel 6-Aryl Substituted Pyrimidine Azo Dyes [DOI]
- 71 Mezgebe, 2022, Synthesis and Pharmacological Activities of Azo Dye Derivatives Incorporating Heterocyclic Scaffolds: A Review [DOI]
- 72 Faikhruea, 2024, Uncovering Factors That Affect the Efficiency of Azo Dye Synthesis in Organic Chemistry Laboratory [DOI]
- 73 Ozgen, 2006, Modified 2,2-Azino-Bis-3-Ethylbenzothiazoline-6-Sulfonic Acid (ABTS) Method to Measure Antioxidant Capacity of Selected Small Fruits and Comparison to Ferric Reducing Antioxidant Power (FRAP) and 2,2‘-Diphenyl-1-Picrylhydrazyl (DPPH) Methods [DOI]
- 74 Madhanraj, 2017, Antioxidant Assay of Gold and Silver Nanoparticles from Edible Basidiomycetes Mushroom Fungi [DOI]
- 75 Sebaugh, 2011, Guidelines for Accurate EC50/IC50 Estimation [DOI]
- 76 2013, Synthesis, Structure and Tautomerism of Two Benzothiazolyl Azo Derivatives of 2-Naphthol: A Crystallographic, NMR and Computational Study [DOI]
- 77 2020, Use of Standardized Units for a Correct Interpretation of IC50 Values Obtained from the Inhibition of the DPPH Radical by Natural Antioxidants [DOI]
- 78 Gulcin, İ., and Alwasel, S.H. (2023). DPPH Radical Scavenging Assay. Processes, 11. [DOI]
- 79 Ilyasov, I.R., Beloborodov, V.L., Selivanova, I.A., and Terekhov, R.P. (2020). ABTS/PP Decolorization Assay of Antioxidant Capacity Reaction Pathways. Int. J. Mol. Sci., 21. [DOI]
- 80 Lee, 2020, Electronic (Donating or Withdrawing) Effects of Ortho-Phenolic Substituents in Dendritic Antioxidants [DOI]
- 81 Lee, C.Y., Sharma, A., Semenya, J., Anamoah, C., Chapman, K.N., and Barone, V. (2020). Computational Study of Ortho-Substituent Effects on Antioxidant Activities of Phenolic Dendritic Antioxidants. Antioxidants, 9. [DOI]
- 82 Cherdtrakulkiat, 2016, Derivatives (Halogen, Nitro and Amino) of 8-Hydroxyquinoline with Highly Potent Antimicrobial and Antioxidant Activities
- 83 Inami, 2012, Chlorine Atom Substitution Influences Radical Scavenging Activity of 6-Chromanol [DOI]
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