Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

On the Apparent Redox Reactivity of “Oxygen-Enriched Water”

  • 16 Accesses


Molecular oxygen-enriched water (OxEW) is advocated in popular media as useful for various health issues, presumably due to involvement of a purported antioxidant activity and to such notions as “active oxygen.” To our knowledge, there are no explicit reports in the scientific literature where such redox reactivity would be described and explained. Reported here are data showing that a commercial preparation of OxEW does display a measurable, albeit very small, antioxidant activity as monitored by reaction with a standard reagent, DPPH. Moreover, OxEW also displays an apparent pro-oxidant reactivity, against caffeic acid. This does not correlate with any UV-vis-detectable contents of chemical substances in the water, nor can it be explained by typical chemical impurities (e.g., hydrogen peroxide or molecular hydrogen) that would arise upon enrichment with molecular oxygen of pure water by the two most common procedures: purging with gaseous O2 or electrolysis. Instead, this apparent redox reactivity is revealed to be due to differences in pH and in chemical content – and the differences in turn are most likely due to the trace amounts of inorganic ions/elements in the OxEW; importantly, electrolysis, which is often employed as a means to generate O2 in OxEW preparation, is also found to enhance the redox effect of OxEW-like preparations. Thus, in line with expectations, the herein-reported data show that there are no long-lived reactive oxygen species, no activated oxygen, and no extra reducing agents in OxEW – but that an apparent weak redox reactivity can still be measured and assigned to simple side effects of the electrolysis procedure presumably performed in order to enrich the sample in oxygen.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7


  1. 1.

    Charton A, Péronnet F, Doutreleau S, Lonsdorfer E, Klein A, Jimenez L, Geny B, Diemunsch P, Richard R (2014) Effect of administration of water enriched in O2 by injection or electrolysis on transcutaneous oxygen pressure in anesthetized pigs. Drug Des Devel Ther 8:1161–1167

  2. 2.

    Reading SA, Yeomans M, Levesque C (2013) Skin oxygen tension is improved by immersion in oxygen-enriched water. Int J Cosmet Sci 35:600–607

  3. 3.

    Piantadosi CA (2006) “Oxygenated” water and athletic performance. Br J Sports Med 40:740

  4. 4.

    Biró A, Tompa A (2014) A Kaqun víz hatása egészséges önkéntesek immunológiai paramétereire. Orv Hetil 155:949–953

  5. 5.

    Understanding The Science Behind Activated Water (2014) [Online]. Available: https://urldefense.proofpoint.com/v2/url?u=https-3A__www.cleanlink.com_cp_article_Understanding-2DThe-2DScience-2DBehind-2DActivated-2DWater-2D-2D17140&d=DwIDaQ&c=vh6FgFnduejNhPPD0fl_yRaSfZy8CWbWnIf4XJhSqx8&r=6A54lXGx7qU4V7zV8wgnyS59B7Bj4w_mGsnGkEXx-tw&m=F_6HoZCO9O3k3afloAMlU39jaFwhcuFWdeNkb3zv3_w&s=g7D_F3sC2SIOfy_cFUnvzpxVdI3baKmFPO8RAowrYcY&e. Accessed 16 Dec 2019

  6. 6.

    Kaqun - Water and more (2019) [Online]. Available: https://urldefense.proofpoint.com/v2/url?u=https-3A__www.kaqun.eu_what-2Dis-2Dkaqun&d=DwIDaQ&c=vh6FgFnduejNhPPD0fl_yRaSfZy8CWbWnIf4XJhSqx8&r=6A54lXGx7qU4V7zV8wgnyS59B7Bj4w_mGsnGkEXx-tw&m=F_6HoZCO9O3k3afloAMlU39jaFwhcuFWdeNkb3zv3_w&s=Q_VSOzW9ZKQF1VtZ9FCp7muBdu3B0fBA-FIfeh-J3JQ&e. Accessed 16 Dec 2019

  7. 7.

    Giulivi C, Cadenas E (1993) The reaction of ascorbic acid with different heme iron redox states of myoglobin. Antioxidant and prooxidant aspects. FEBS Lett 332:287–290

  8. 8.

    Toma VA, Farcas AD, Roman I, Sevastre B, Hathazi D, Scurtu F, Damian G, Silaghi-Dumitrescu R (2016) Comparative In Vivo Effects of Hemoglobin-Based Oxygen Carriers (HBOC) with Varying Prooxidant and Physiological Reactivity. PLoS One 11:e0153909

  9. 9.

    Khan HY, Zubair H, Faisal M, Ullah MF, Farhan M, Sarkar FH, Ahmad A, Hadi SM (2014) Plant polyphenol induced cell death in human cancer cells involves mobilization of intracellular copper ions and reactive oxygen species generation: a mechanism for cancer chemopreventive action. Mol Nutr Food Res 58:437–446

  10. 10.

    Moţ AC, Coman C, Miron C, Damian G, Sarbu C, Silaghi-Dumitrescu R (2014) An assay for pro-oxidant reactivity based on phenoxyl radicals generated by laccase. Food Chem 143:214–222

  11. 11.

    Bischin C, Contra G, Tusan C, Miclea P, Taciuc V, Parvu M, Silaghi-Dumitrescu R (2018) Free-radical reactions: the fine line between the anti- and pro-oxidant reactivities. Oxid Commun 41:130–140

  12. 12.

    Gaina L et al (2014) Microwave assisted synthesis, photophysical and redox properties of (phenothiazinyl)vinyl-pyridinium dyes. Dyes Pigments 102:315–325

  13. 13.

    Gǎinǎ LI et al (2013) Microwave-Assisted Catalytic Amination of Phenothiazine; Reliable Access to Phenothiazine Analogues of Troger’s Base. Eur J Org Chem 2013:5500–5508

  14. 14.

    Volbeda A, Darnault C, Parkin A, Sargent F, Armstrong FA, Fontecilla-Camps JC (2013) Crystal structure of the O(2)-tolerant membrane-bound hydrogenase 1 from Escherichia coli in complex with its cognate cytochrome b. Structure 21:184–190

  15. 15.

    Olson KR, Gao Y, DeLeon ER, Arif M, Arif F, Arora N, Straub KD (2017) Catalase as a sulfide-sulfur oxido-reductase: An ancient (and modern?) regulator of reactive sulfur species (RSS). Redox Biol 12:325–339

  16. 16.

    Loer SA, Scheeren TWL, Tarnow J (1998) How much oxygen does the human lung consume? Anesthesiology 31:305–309

  17. 17.

    Mocan A et al (2014) Polyphenolic content, antioxidant and antimicrobial activities of Lycium barbarum L. and Lycium chinense Mill. leaves. Molecules 19:10056–10073

  18. 18.

    Dezsi S, Badarau AS, Bischin C, Vodnar DCC, Silaghi-Dumitrescu R, Gheldiu A-MM, Mocan A, Vlase L (2015) Antimicrobial and antioxidant activities and phenolic profile of Eucalyptus globulus Labill. and Corymbia ficifolia (F. Muell.) K.D. Hill & L.A.S. Johnson leaves. Molecules 20:4720–4734

  19. 19.

    Mocan A, Vlase L, Arsene AL, Vodnar D, Bischin C, Silaghi-Dumitrescu R, Crişan G (2015) HPLC/MS analysis of caffeic and chlorogenic acids from three romanian veronica species and their antioxidant and antimicrobial properties. Farmacia 63:890–896

  20. 20.

    Mureşan B, Cimpoiu C, Hosu A, Bischin C, Gal E, Damian G, Fischer-Fodor E, Silaghi-Dumitrescu R (2015) Antioxidant content in romanian traditional distilled alcoholic beverages. Stud Univ Babes-Bolyai Chem 60:355–370

  21. 21.

    Benedec D, Hanganu D, Oniga I, Filip L, Bischin C, Silaghi-Dumitrescu R, Tiperciuc B, Vlase L (2016) Achillea schurii flowers: Chemical, antioxidant, and antimicrobial investigations. Molecules 21:1050

  22. 22.

    Benedec D, Hanganu D, Oniga I, Tiperciuc B, Olah NK, Raita O, Bischin C, Silaghi-Dumitrescu R, Vlase L (2015) Assessment of rosmarinic acid content in six Lamiaceae species extracts and their antioxidant and antimicrobial potential. Pak J Pharm Sci 28:2297–2303

  23. 23.

    Mot ACC, Bischin C, Muresan B, Parvu M, Damian G, Vlase L, Silaghi-Dumitrescu R (2016) Antioxidant activity evaluation by physiologically relevant assays based on haemoglobin peroxidase activity and cytochrome c-induced oxidation of liposomes. Nat Prod Res 30:1315–1319

  24. 24.

    Mot AC, Bischin C, Damian G, Silaghi-Dumitrescu R (2015) Antioxidant activity evaluation involving hemoglobin-related free radical reactivity. Methods Mol Biol 1208:247–255

  25. 25.

    Vijayalakshmi G, Adinarayana M, Rao PJ (2010) Kinetics and mechanisms of oxidation of some antioxidants with photochemically generated tert-butoxyl radicals. Indian J Biochem Biophys 47:292–297

  26. 26.

    Hathazi D, Mot AC, Vaida A, Scurtu F, Lupan I, Fischer-Fodor E, Damian G, Kurtz DM Jr, Silaghi-Dumitescu R (2014) Oxidative protection of hemoglobin and hemerythrin by cross-linking with a nonheme iron peroxidase: potentially improved oxygen carriers for use in blood substitutes. Biomacromolecules 15:1920–1927

  27. 27.

    Puscas C et al (2018) The high affinity of small-molecule antioxidants for hemoglobin. Free Radic Biol Med 124:260–274

  28. 28.

    Hathazi D, Scurtu F, Bischin C, Mot A, Attia A, Kongsted J, Silaghi-Dumitrescu R (2018) The Reaction of Oxy Hemoglobin with Nitrite: Mechanism, Antioxidant-Modulated Effect, and Implications for Blood Substitute Evaluation. Molecules 23:E350

  29. 29.

    Simonetti P, Gardana C, Pietta P (2001) Plasma levels of caffeic acid and antioxidant status after red wine intake. J Agric Food Chem 49:5964–5968

  30. 30.

    Du GJ, Zhang Z, Wen XD, Yu C, Calway T, Yuan CS, Wang CZ (2012) Epigallocatechin Gallate (EGCG) is the most effective cancer chemopreventive polyphenol in green tea. Nutrients 4:1679–1691

  31. 31.

    Marrelli M, Loizzo MR, Nicoletti M, Menichini F, Conforti F (2014) In vitro investigation of the potential health benefits of wild Mediterranean dietary plants as anti-obesity agents with alpha-amylase and pancreatic lipase inhibitory activities. J Sci Food Agric 94:2217–2224

  32. 32.

    Weng CJ, Yen GC (2012) Chemopreventive effects of dietary phytochemicals against cancer invasion and metastasis: phenolic acids, monophenol, polyphenol, and their derivatives. Cancer Treat Rev 38:76–87

  33. 33.

    Zessner H et al (2008) Fractionation of polyphenol-enriched apple juice extracts to identify constituents with cancer chemopreventive potential. Mol Nutr Food Res 52(Suppl 1):S28–S44

  34. 34.

    de Souza RFV, De Giovani WF (2004) Antioxidant properties of complexes of flavonoids with metal ions. Redox Rep 9:97–104

  35. 35.

    Ikeda NEA, Novak EM, Maria DA, Velosa AS, Pereira RMS (2015) Synthesis, characterization and biological evaluation of Rutin-zinc(II) flavonoid -metal complex. Chem Biol Interact

  36. 36.

    Bischin C, Tusan C, Bartok A, Septelean R, Damian G, Silaghi-Dumitrescu R (2015) Evaluation of the biochemical effects of silyl-phosphaalkenes on oxidative and nitrosative stress pathways involving metallocenters. Phosphorus Sulfur Silicon Relat Elem 190:292–299

  37. 37.

    Mot AC, Bischin C, Damian G, Silaghi-Dumitrescu R (2015) Antioxidant activity evaluation involving hemoglobin- related free radical reactivity. Methods Mol Biol 1208:247–255

  38. 38.

    Rogers MS, Patel RP, Reeder BJ, Sarti P, Wilson MT, Alayash AI (1995) Prooxidant Effects of Cross-Linked Hemoglobins Explored Using Liposome and Cytochrome-C-Oxidase Vesicle Model Membranes. Biochem J 310:827–833

  39. 39.

    Reeder BJ, Wilson MT (1998) Mechanism of reaction of myoglobin with the lipid hydroperoxide hydroperoxyoctadecadienoic acid. Biochem J 330:1317–1323

  40. 40.

    Reeder BJ, Wilson MT (2001) The effects of pH on the mechanism of hydrogen peroxide and lipid hydroperoxide consumption by myoglobin: a role for the protonated ferryl species. Free Radic Biol Med 30:1311–1318

Download references


Profs. P. Ilea, Sorin Dorneanu, Andrei Stefancu, Augustin Mot (BBU), and Dr. Silvia Claudia Moşneag (Somes Water Company, Water Analysis Laboratory of the WTP Gilău) are thankful for helpful discussions.


This work was supported by Romanian Ministry for Research and Innovation, Projects PNIII-P2-2.1-PED-2016-1415, 142PED/2017.

Author information

Correspondence to Radu Silaghi-Dumitrescu.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Electronic supplementary material


(DOCX 268 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Pușcaș, C., Moldovan, M., Silaghi-Dumitrescu, L. et al. On the Apparent Redox Reactivity of “Oxygen-Enriched Water”. Biol Trace Elem Res (2020). https://doi.org/10.1007/s12011-020-02056-4

Download citation


  • Oxidative stress
  • Oxygen-enriched water
  • DPPH
  • ESR
  • Caffeic acid
  • Electrolysis