Photophysical properties prediction of selenium- and tellurium-substituted thymidine as potential UVA chemotherapeutic agents

Pirillo, Jenny; Simone, Bruna Clara De; Russo, Nino

doi:10.1007/s00214-015-1744-1

Cited by 43 publications

(48 citation statements)

References 36 publications

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“…The experimentally measured large redshift in absorption, the ultrafast and efficient population of the triplet state, and the high yield of singlet oxygen generation reported for the 4-thiouracil and 4-thiothymine derivatives (17,46,91,93,96,121) have also stimulated several static and dynamics simulations (91,96,103,104,109,114,121,144). According to these calculations, excitation of 4-thiouracil or 4-thiothymine derivatives with UVA radiation populates the S 2 (p S p*) state directly, while the S 1 (n S p*) state is shown to exhibit negligible oscillator strength in the Franck-Condon region.…”

Section: Thiopyrimidine Derivativesmentioning

confidence: 98%

“…The tail redshifts with decreasing solvent polarity, suggesting that it originates from an n S p* transition (B. Ashwood, M. Pollum, C. E. Crespo-Hern andez, unpublished results) (55,93,96,98). Vertical excitation energies obtained using single-reference and multiconfigurational computational methods predict that the lowest-energy absorption maximum is due to a S 2 (p S p*) transition in the thiouracil and thiothymine derivatives (54,74,92,96,98,103,(106)(107)(108)(109)(110)(111)(112)(113)(114)(115)(116), while it has been assigned primarily to a S 4 (p S p*) transition in 2-thiocytosine (54). Similarly, the absorption tail has been assigned to a S 1 (n S p*) transition in the thiothymine and thiouracil derivatives, while it has been assigned to a combination of S 2 (p S p*) and S 1 (n S p*) transitions in 2-thiocytosine (98,103,106).…”

Section: Absorption and Emission Of Thiopyrimidine Derivativesmentioning

confidence: 98%

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Photochemical and Photodynamical Properties of Sulfur‐Substituted Nucleic Acid Bases,

Ashwood

Pollum

Crespo‐Hernández

2018

Photochem & Photobiology

115

132

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Sulfur-substituted nucleobases (a.k.a., thiobases) are among the world's leading prescriptions for chemotherapy and immunosuppression. Long-term treatment with azathioprine, 6-mercaptopurine and 6-thioguanine has been correlated with the photoinduced formation of carcinomas. Establishing an in-depth understanding of the photochemical properties of these prodrugs may provide a route to overcoming these carcinogenic side effects, or, alternatively, a basis for developing effective compounds for targeted phototherapy. In this review, a broad examination is undertaken, surveying the basic photochemical properties and excited-state dynamics of sulfur-substituted analogs of the canonical DNA and RNA nucleobases. A molecular-level understanding of how sulfur substitution so remarkably perturbs the photochemical properties of the nucleobases is presented by combining experimental results with quantum-chemical calculations. Structure-property relationships demonstrate the impact of site-specific sulfur substitution on the photochemical properties, particularly on the population of the reactive triplet state. The value of fundamental photochemical investigations for driving the development of ultraviolet-A chemotherapeutics is showcased. The most promising photodynamic agents identified thus far have been investigated in various carcinoma cell lines and shown to decrease cell proliferation upon exposure to ultraviolet-A radiation. Overarching principles have been elucidated for the impact that sulfur substitution of the carbonyl oxygen has on the photochemical properties of the nucleobases.

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Section: Thiopyrimidine Derivativesmentioning

confidence: 98%

Section: Absorption and Emission Of Thiopyrimidine Derivativesmentioning

confidence: 98%

Photochemical and Photodynamical Properties of Sulfur‐Substituted Nucleic Acid Bases,

Ashwood

Pollum

Crespo‐Hernández

2018

Photochem & Photobiology

115

132

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“…The SOC elements are given as the root of the sum of the square of the three hyperfine components: (SOC elements for the thio-substituted Thd in the gas phase have been recently reported at TD-B3LYP level in ref. 24 . These values agree with ours within 20 cm -1 .…”

Section: Intersystem Crossingmentioning

confidence: 99%

Why Replacing Different Oxygens of Thymine with Sulfur Causes Distinct Absorption and Intersystem Crossing

Bai

Barbatti

2016

J. Phys. Chem. A

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Recent experiments replacing oxygen atoms by sulfur in thymine have revealed that absorption and intersystem crossing properties of these derivatives are strongly dependent on the position and number of the substitutions, affecting their potential performance for photodynamical therapy. Using multireference quantum chemical methods (CASPT2 and DFT/MRCI), we calculated absorption spectra and spin-orbit coupling matrix elements for thymine (Thy), 2-thiothymine (2tThy), 4-thiothymine (4tThy), and 2,4-dithiothymine (2,4dtThy), to investigate this relation between structure and photophysics. The simulations showed that a simple 4-electrons/4-orbital minimum model can explain the main experimentally observed spectral features. Moreover, the computational estimate of intersystem crossing lifetimes in this sequence of molecules revealed that the experimental value attributed to thymine in water might be underestimated by a factor 20, most probably due to an overlap of singlet/triplet absorption signals in the transient absorption spectrum. The difference between the absorptivity of 2tThy and 2tThd was also investigated, but no conclusive explanation could be found.

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“…The theoretical studies including density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were used to assess a series of photophysical properties, including absorption spectra, excitation energies (singlet and triplet) and spin–orbit matrix elements. All the reported compounds are potential UVA chemotherapeutic agents which require the lowest triplet-state energy for producing highly cytotoxic ROS [ 160 , 161 ].…”

Section: Theorical Studies For Assessing the Photoactivity Of Natumentioning

confidence: 99%

Role of Photoactive Phytocompounds in Photodynamic Therapy of Cancer

et al. 2020

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Cancer is one of the greatest life-threatening diseases conventionally treated using chemo- and radio-therapy. Photodynamic therapy (PDT) is a promising approach to eradicate different types of cancers. PDT requires the administration of photosensitisers (PSs) and photoactivation using a specific wavelength of light in the presence of molecular oxygen. This photoactivation exerts an anticancer effect via apoptosis, necrosis, and autophagy of cancer cells. Recently, various natural compounds that exhibit photosensitising potentials have been identified. Photoactive substances derived from medicinal plants have been found to be safe in comparison with synthetic compounds. Many articles have focused on PDT mechanisms and types of PSs, but limited attention has been paid to the phototoxic activities of phytocompounds. The reduced toxicity and side effects of natural compounds inspire the researchers to identify and use plant extracts or phytocompounds as a potent natural PS candidate for PDT. This review focusses on the importance of common photoactive groups (furanocoumarins, polyacetylenes, thiophenes, curcumins, alkaloids, and anthraquinones), their phototoxic effects, anticancer activity and use as a potent PS for an effective PDT outcome in the treatment of various cancers.

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Photophysical properties prediction of selenium- and tellurium-substituted thymidine as potential UVA chemotherapeutic agents

Cited by 43 publications

References 36 publications

Photochemical and Photodynamical Properties of Sulfur‐Substituted Nucleic Acid Bases,

Photochemical and Photodynamical Properties of Sulfur‐Substituted Nucleic Acid Bases,

Why Replacing Different Oxygens of Thymine with Sulfur Causes Distinct Absorption and Intersystem Crossing

Role of Photoactive Phytocompounds in Photodynamic Therapy of Cancer

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