We report on porphyrin-flavonol hybrids consisting of a porphyrin antenna and four covalently bound 3-hydroxyflavone (flavonol) groups, which act as highly efficient photoactivatable carbon monoxide (CO)-releasing molecules (photoCORMs). These bichromophoric systems enable activation of the UV-absorbing flavonol chromophore by visible light up to 650 nm and offer precise spatial and temporal control of CO administration. The physicochemical properties of the porphyrin antenna system can also be tuned by inserting a metal cation. Our computational study revealed that the process occurs via endergonic triplet-triplet energy transfer from porphyrin to flavonol and may become feasible thanks to flavonol energy stabilization upon intramolecular proton transfer. This mechanism was also indirectly supported by steady-state and transient absorption spectroscopy techniques. Additionally, the porphyrin-flavonol hybrids were found to be biologically benign. With four flavonol CO donors attached to a single porphyrin chromophore, high CO release yields, excellent uncaging cross sections, low toxicity, and CO therapeutic properties, these photoCORMs offer exceptional potential for their further development and future biological and medical applications.

Department of Chemistry Faculty of Science Masaryk University Kamenice 5 62500 Brno Czech Republic

Department of Physical Chemistry University of Chemistry and Technology Technická 5 16628 Prague 6 Czech Republic

ELI Beamlines Facility The Extreme Light Infrastructure ERIC Za Radnicí 835 25241 Dolní Břežany Czech Republic

Institute of Medical Biochemistry and Laboratory Diagnostics and 4th Department of Internal Medicine General University Hospital Prague and 1st Faculty of Medicine Charles University Na Bojišti 3 12108 Prague 2 Czech Republic

RECETOX Faculty of Science Masaryk University Kamenice 5 62500 Brno Czech Republic

Zobrazit více v PubMed

Romão C. C.; Blättler W. A.; Seixas J. D.; Bernardes G. J. Developing drug molecules for therapy with carbon monoxide. Chem. Soc. Rev. 2012, 41, 3571–3583. 10.1039/c2cs15317c. PubMed DOI

Lu W.; Yang X.; Wang B. Carbon monoxide signaling and soluble guanylyl cyclase: Facts, myths, and intriguing possibilities. Biochem. Pharmacol. 2022, 200, 115041.10.1016/j.bcp.2022.115041. PubMed DOI PMC

Wang B.; Otterbein L. E.. Carbon Monoxide in Drug Discovery: Basics, Pharmacology, and Therapeutic Potential; John Wiley & Sons: Hoboken, NJ, USA, 2022.

Ling K.; Men F.; Wang W.-C.; Zhou Y.-Q.; Zhang H.-W.; Ye D.-W. Carbon monoxide and its controlled release: therapeutic application, detection, and development of carbon monoxide releasing molecules (CORMs) miniperspective. J. Med. Chem. 2018, 61, 2611–2635. 10.1021/acs.jmedchem.6b01153. PubMed DOI

Motterlini R.; Otterbein L. E. The therapeutic potential of carbon monoxide. Nat. Rev. Drug Discovery 2010, 9, 728–743. 10.1038/nrd3228. PubMed DOI

Vítek L.; Gbelcová H.; Muchová L.; Váňová K.; Zelenka J.; Koníčková R.; Šuk J.; Zadinova M.; Knejzlík Z.; Ahmad S.; et al. Antiproliferative effects of carbon monoxide on pancreatic cancer. Dig. Liver Dis. 2014, 46, 369–375. 10.1016/j.dld.2013.12.007. PubMed DOI

Vander Heiden M. G.; Cantley L. C.; Thompson C. B. Understanding the Warburg effect: the metabolic requirements of cell proliferation. Science 2009, 324, 1029–1033. 10.1126/science.1160809. PubMed DOI PMC

Wegiel B.; Gallo D.; Csizmadia E.; Harris C.; Belcher J.; Vercellotti G. M.; Penacho N.; Seth P.; Sukhatme V.; Ahmed A.; et al. Carbon Monoxide Expedites Metabolic Exhaustion to Inhibit Tumor Growth. Cancer Res. 2013, 73, 7009–7021. 10.1158/0008-5472.can-13-1075. PubMed DOI PMC

Pinto M. N.; Mascharak P. K. Light-assisted and remote delivery of carbon monoxide to malignant cells and tissues: Photochemotherapy in the spotlight. J. Photochem. Photobiol., C 2020, 42, 100341.10.1016/j.jphotochemrev.2020.100341. DOI

Weinstain R.; Slanina T.; Kand D.; Klan P. Visible-to-NIR-light activated release: from small molecules to nanomaterials. Chem. Rev. 2020, 120, 13135–13272. 10.1021/acs.chemrev.0c00663. PubMed DOI PMC

Allison R. R.; Sibata C. H. Oncologic photodynamic therapy photosensitizers: a clinical review. Photodiagn. Photodyn. Ther. 2010, 7, 61–75. 10.1016/j.pdpdt.2010.02.001. PubMed DOI

Carrington S. J.; Chakraborty I.; Bernard J. M.; Mascharak P. K. A theranostic two-tone luminescent PhotoCORM derived from Re (I) and (2-pyridyl)-benzothiazole: trackable CO delivery to malignant cells. Inorg. Chem. 2016, 55, 7852–7858. 10.1021/acs.inorgchem.6b00511. PubMed DOI

Martinek M.; Filipova L.; Galeta J.; Ludvíková L.; Klan P. Photochemical formation of dibenzosilacyclohept-4-yne for Cu-free click chemistry with azides and 1, 2, 4, 5-Tetrazines. Org. Lett. 2016, 18, 4892–4895. 10.1021/acs.orglett.6b02367. PubMed DOI

Poloukhtine A. A.; Mbua N. E.; Wolfert M. A.; Boons G.-J.; Popik V. V. Selective labeling of living cells by a photo-triggered click reaction. J. Am. Chem. Soc. 2009, 131, 15769–15776. 10.1021/ja9054096. PubMed DOI PMC

Chapman O.; Wojtkowski P.; Adam W.; Rodriguez O.; Rucktaeschel R. Photochemical transformations. XLIV. Cyclic peroxides. Synthesis and chemistry of. alpha.-lactones. J. Am. Chem. Soc. 1972, 94, 1365–1367. 10.1021/ja00759a060. DOI

Peng P.; Wang C.; Shi Z.; Johns V. K.; Ma L.; Oyer J.; Copik A.; Igarashi R.; Liao Y. Visible-light activatable organic CO-releasing molecules (PhotoCORMs) that simultaneously generate fluorophores. Org. Biomol. Chem. 2013, 11, 6671–6674. 10.1039/c3ob41385c. PubMed DOI

Antony L. A. P.; Slanina T.; Sebej P.; Solomek T.; KlAn P. Fluorescein analogue xanthene-9-carboxylic acid: a transition-metal-free CO releasing molecule activated by green light. Org. Lett. 2013, 15, 4552–4555. 10.1021/ol4021089. PubMed DOI

Palao E.; Slanina T.; Muchová L.; Solomek T.; Vitek L.; Klan P. Transition-metal-free CO-releasing BODIPY derivatives activatable by visible to NIR light as promising bioactive molecules. J. Am. Chem. Soc. 2016, 138, 126–133. 10.1021/jacs.5b10800. PubMed DOI

Pietta P.-G. Flavonoids as antioxidants. J. Nat. Prod. 2000, 63, 1035–1042. 10.1021/np9904509. PubMed DOI

Studer S. L.; Brewer W. E.; Martinez M. L.; Chou P. T. Time-resolved study of the photooxygenation of 3-hydroxyflavone. J. Am. Chem. Soc. 1989, 111, 7643–7644. 10.1021/ja00201a071. DOI

Chou P.-T.; Martinez M. L. Photooxygenation of 3-hydroxyflavone and molecular design of the radiation-hard scintillator based on the excited-state proton transfer. Radiat. Phys. Chem. 1993, 41, 373–378. 10.1016/0969-806X(93)90074-5. DOI

Anderson S. N.; Richards J. M.; Esquer H. J.; Benninghoff A. D.; Arif A. M.; Berreau L. M. A structurally-tunable 3-hydroxyflavone motif for visible light-induced carbon monoxide-releasing molecules (CORMs). ChemistryOpen 2015, 4, 590–594. 10.1002/open.201500167. PubMed DOI PMC

Lazarus L. S.; Esquer H. J.; Benninghoff A. D.; Berreau L. M. Sense and release: a thiol-responsive flavonol-based photonically driven carbon monoxide-releasing molecule that operates via a multiple-input AND logic gate. J. Am. Chem. Soc. 2017, 139, 9435–9438. 10.1021/jacs.7b04077. PubMed DOI

Russo M.; Orel V.; Stacko P.; Srankova M.; Muchova L.; Vitek L.; Klan P. Structure-Photoreactivity Relationship of 3-Hydroxyflavone-Based CO-Releasing Molecules. J. Org. Chem. 2022, 87, 4750–4763. 10.1021/acs.joc.2c00032. PubMed DOI

Russo M.; Stacko P.; Nachtigallova D.; Klan P. Mechanisms of orthogonal photodecarbonylation reactions of 3-hydroxyflavone-based acid-base forms. J. Org. Chem. 2020, 85, 3527–3537. 10.1021/acs.joc.9b03248. PubMed DOI

Stackova L.; Russo M.; Muchova L.; Orel V.; Vitek L.; Stacko P.; Klan P. Cyanine-Flavonol Hybrids for Near-Infrared Light-Activated Delivery of Carbon Monoxide. Chem.—Eur. J. 2020, 26, 13184–13190. 10.1002/chem.202003272. PubMed DOI PMC

Yang Q.; Muchova L.; Stackova L.; Stacko P.; Šindelář V.; Vitek L.; Klan P. Cyanine-flavonol hybrids as NIR-light activatable carbon monoxide donors in methanol and aqueous solutions. Chem. Commun. 2022, 58, 8958–8961. 10.1039/D2CC02648A. PubMed DOI

Cheng J.; Gan G.; Shen Z.; Gao L.; Zhang G.; Hu J. Red Light-Triggered Intracellular Carbon Monoxide Release Enables Selective Eradication of MRSA Infection. Angew. Chem. 2021, 133, 13625–13632. 10.1002/ange.202104024. PubMed DOI

Sekhar A. R.; Chitose Y.; Janos J.; Dangoor S. I.; Ramundo A.; Satchi-Fainaro R.; Slavicek P.; Klan P.; Weinstain R. Porphyrin as a versatile visible-light-activatable organic/metal hybrid photoremovable protecting group. Nat. Commun. 2022, 13, 3614. PubMed PMC

Alabugin A. Near-IR Photochemistry for Biology: Exploiting the Optical Window of Tissue. Photochem. Photobiol. 2019, 95, 722–732. 10.1111/php.13068. PubMed DOI

Gouterman M.; Wagnière G. H.; Snyder L. C. Spectra of porphyrins: Part II. Four orbital model. J. Mol. Spectrosc. 1963, 11, 108–127. 10.1016/0022-2852(63)90011-0. DOI

Mandal A. K.; Taniguchi M.; Diers J. R.; Niedzwiedzki D. M.; Kirmaier C.; Lindsey J. S.; Bocian D. F.; Holten D. Photophysical properties and electronic structure of porphyrins bearing zero to four meso-phenyl substituents: New insights into seemingly well understood tetrapyrroles. J. Phys. Chem. A 2016, 120, 9719–9731. 10.1021/acs.jpca.6b09483. PubMed DOI

Dąbrowski J. M.; Pucelik B.; Regiel-Futyra A.; Brindell M.; Mazuryk O.; Kyzioł A.; Stochel G.; Macyk W.; Arnaut L. G. Engineering of relevant photodynamic processes through structural modifications of metallotetrapyrrolic photosensitizers. Coord. Chem. Rev. 2016, 325, 67–101. 10.1016/j.ccr.2016.06.007. DOI

Dávila Y. A.; Sancho M. I.; Almandoz M. C.; Blanco S. E. Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic-Water Mixtures. Determination of the Thermodynamic pKa Values by UV-Visible Spectroscopy and DFT Calculations. J. Chem. Eng. Data 2013, 58, 1706–1716. 10.1021/je400153r. DOI

Avani R.; Busa K. P.; Mahetar J. G.; Shah M. K. A facile synthetic approach for the syntheses of 7-hydroxyflavonol derivatives. Der Pharma Chem. 2015, 7, 142–146.

Lindsey J. S.; Hsu H. C.; Schreiman I. C. Synthesis of tetraphenylporphyrins under very mild conditions. Tetrahedron Lett. 1986, 27, 4969–4970. 10.1016/S0040-4039(00)85109-6. DOI

Gouterman M. Spectra of porphyrins. J. Mol. Spectrosc. 1961, 6, 138–163. 10.1016/0022-2852(61)90236-3. DOI

Cavaleiro J. A. S.; Neves M. G. P. S.; Hewlins M. J. E.; Jackson A. H. The photo-oxidation of meso-tetraphenylporphyrins. J. Chem. Soc., Perkin Trans. 1 1990, 1937–1943. 10.1039/p19900001937. DOI

Kalyanasundaram K.; Neumann-Spallart M. Photophysical and redox properties of water-soluble porphyrins in aqueous media. J. Phys. Chem. 1982, 86, 5163–5169. 10.1021/j100223a022. DOI

Dick B. AM1 and INDO/S calculations on electronic singlet and triplet states involved in excited-state intramolecular proton transfer of 3-hydroxyflavone. J. Phys. Chem. 1990, 94, 5752–5756. 10.1021/j100378a028. DOI

Sengupta P. K.; Kasha M. Excited state proton-transfer spectroscopy of 3-hydroxyflavone and quercetin. Chem. Phys. Lett. 1979, 68, 382–385. 10.1016/0009-2614(79)87221-8. DOI

Schwartz B. J.; Peteanu L. A.; Harris C. B. Direct observation of fast proton transfer: femtosecond photophysics of 3-hydroxyflavone. J. Phys. Chem. 1992, 96, 3591–3598. 10.1021/j100188a009. DOI

Hammes-Schiffer S.; Stuchebrukhov A. A. Theory of Coupled Electron and Proton Transfer Reactions. Chem. Rev. 2010, 110, 6939–6960. 10.1021/cr1001436. PubMed DOI PMC

Migliore A.; Polizzi N. F.; Therien M. J.; Beratan D. N. Biochemistry and Theory of Proton-Coupled Electron Transfer. Chem. Rev. 2014, 114, 3381–3465. 10.1021/cr4006654. PubMed DOI PMC

Warren J. J.; Tronic T. A.; Mayer J. M. Thermochemistry of Proton-Coupled Electron Transfer Reagents and its Implications. Chem. Rev. 2010, 110, 6961–7001. 10.1021/cr100085k. PubMed DOI PMC

Murray P. R. D.; Cox J. H.; Chiappini N. D.; Roos C. B.; McLoughlin E. A.; Hejna B. G.; Nguyen S. T.; Ripberger H. H.; Ganley J. M.; Tsui E.; Shin N. Y.; Koronkiewicz B.; Qiu G.; Knowles R. R. Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis. Chem. Rev. 2022, 122, 2017–2291. 10.1021/acs.chemrev.1c00374. PubMed DOI PMC

Amoretti M.; Amsler C.; Bonomi G.; Bouchta A.; Bowe P.; Carraro C.; Cesar C. L.; Charlton M.; Collier M. J. T.; Doser M.; Filippini V.; Fine K. S.; Fontana A.; Fujiwara M. C.; Funakoshi R.; Genova P.; Hangst J. S.; Hayano R. S.; Holzscheiter M. H.; Jørgensen L. V.; Lagomarsino V.; Landua R.; Lindelöf D.; Rizzini E. L.; Macrì M.; Madsen N.; Manuzio G.; Marchesotti M.; Montagna P.; Pruys H.; Regenfus C.; Riedler P.; Rochet J.; Rotondi A.; Rouleau G.; Testera G.; Variola A.; Watson T. L.; van der Werf D. P. Production and detection of cold antihydrogen atoms. Nature 2002, 419, 456–459. 10.1038/nature01096. PubMed DOI

Parada G. A.; Goldsmith Z. K.; Kolmar S.; Pettersson Rimgard B.; Mercado B. Q.; Hammarström L.; Hammes-Schiffer S.; Mayer J. M. Concerted proton-electron transfer reactions in the Marcus inverted region. Science 2019, 364, 471–475. 10.1126/science.aaw4675. PubMed DOI PMC

Pettersson Rimgard B.; Tao Z.; Parada G. A.; Cotter L. F.; Hammes-Schiffer S.; Mayer J. M.; Hammarström L. Proton-coupled energy transfer in molecular triads. Science 2022, 377, 742–747. 10.1126/science.abq5173. PubMed DOI PMC

Wu P. G.; Brand L. Resonance Energy Transfer: Methods and Applications. Anal. Biochem. 1994, 218, 1–13. 10.1006/abio.1994.1134. PubMed DOI

Fang B.; Shen Y.; Peng B.; Bai H.; Wang L.; Zhang J.; Hu W.; Fu L.; Zhang W.; Li L.; Huang W. Small-Molecule Quenchers for Förster Resonance Energy Transfer: Structure, Mechanism, and Applications. Angew. Chem., Int. Ed. 2022, 61, e20220718810.1002/anie.202207188. PubMed DOI

Klan P.; Wirz J.. Photochemistry of Organic Compounds: Fom Concepts to Practice; John Wiley & Sons: Chichester, UK, 2009.

Lai R.; Liu Y.; Luo X.; Chen L.; Han Y.; Lv M.; Liang G.; Chen J.; Zhang C.; Di D.; Scholes G. D.; Castellano F. N.; Wu K. Shallow distance-dependent triplet energy migration mediated by endothermic charge-transfer. Nat. Commun. 2021, 12, 1532.10.1038/s41467-021-21561-1. PubMed DOI PMC

Cheng Y. Y.; Fückel B.; Khoury T.; Clady R. G. C. R.; Ekins-Daukes N. J.; Crossley M. J.; Schmidt T. W. Entropically Driven Photochemical Upconversion. J. Phys. Chem. A 2011, 115, 1047–1053. 10.1021/jp108839g. PubMed DOI

Isokuortti J.; Kuntze K.; Virkki M.; Ahmed Z.; Vuorimaa-Laukkanen E.; Filatov M. A.; Turshatov A.; Laaksonen T.; Priimagi A.; Durandin N. A. Expanding excitation wavelengths for azobenzene photoswitching into the near-infrared range via endothermic triplet energy transfer. Chem. Sci. 2021, 12, 7504–7509. 10.1039/D1SC01717A. PubMed DOI PMC

Tang Q.; Zhang H.-L.; Wang Y.; Liu J.; Yang S.-P.; Liu J.-G. Mitochondria-targeted carbon monoxide delivery combined with singlet oxygen production from a single nanoplatform under 808 nm light irradiation for synergistic anticancer therapy. J. Mater. Chem. B 2021, 9, 4241–4248. 10.1039/D1TB00478F. PubMed DOI

Queiroga C. S. F.; Almeida A. S.; Vieira H. L. A. Carbon Monoxide Targeting Mitochondria. Biochem. Res. Int. 2012, 2012, 1–9. 10.1155/2012/749845. PubMed DOI PMC

Motterlini R.; Foresti R. Biological signaling by carbon monoxide and carbon monoxide-releasing molecules. Am. J. Physiol.: Cell Physiol. 2017, 312, C302–C313. 10.1152/ajpcell.00360.2016. PubMed DOI

Lazarus L. S.; Simons C. R.; Arcidiacono A.; Benninghoff A. D.; Berreau L. M. Extracellular vs Intracellular Delivery of CO: Does It Matter for a Stable, Diffusible Gasotransmitter?. J. Med. Chem. 2019, 62, 9990–9995. 10.1021/acs.jmedchem.9b01254. PubMed DOI PMC

Gomes A.; Neves M.; Cavaleiro J. A. S. Cancer, Photodynamic Therapy and Porphyrin-Type Derivatives. An. Acad. Bras. Cienc. 2018, 90, 993–1026. 10.1590/0001-3765201820170811. PubMed DOI

Vítek L.; Gbelcová H.; Muchová L.; Váňová K.; Zelenka J.; Koníčková R.; Šuk J.; Zadinova M.; Knejzlík Z.; Ahmad S.; Fujisawa T.; Ahmed A.; Ruml T. Antiproliferative effects of carbon monoxide on pancreatic cancer. Dig. Liver Dis. 2014, 46, 369–375. 10.1016/j.dld.2013.12.007. PubMed DOI

Carbon Monoxide-Releasing Activity of Plant Flavonoids

Structure-Photoreactivity Relationship Study of Substituted 3-Hydroxyflavones and 3-Hydroxyflavothiones for Improving Carbon Monoxide Photorelease