Nanostructured TiO2 Catalyzed Oxidations of Caffeine and Isocaffeine and Their Cytotoxicity and Genotoxicity Towards Ovarian Cancer Cells

Xiaoxi Huang; Anandarup Goswami; Xiaoxin Zou; Stephanie Hayes; Vatsal Shah; Tamara Minko; Zhimin Tao; Tewodros Asefa

doi:https://doi.org/10.1007/s12668-013-0120-7

Nanostructured TiO₂ Catalyzed Oxidations of Caffeine and Isocaffeine and Their Cytotoxicity and Genotoxicity Towards Ovarian Cancer Cells

Xiaoxi Huang, Anandarup Goswami, Xiaoxin Zou, Stephanie Hayes, Vatsal Shah, Tamara Minko, Zhimin Tao, Tewodros Asefa

Rutgers, The State University

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

Abstract

Although caffeine is well-known as an antioxidant and a psychoactive stimulant, its antioxidative properties and biological activities under various conditions are still largely unknown. The same can be said about caffeine’s isomer, isocaffeine, whose properties have been even less investigated. Furthermore, much remains unknown about the potential biological effects and anticancer properties of the oxidative products of caffeine and isocaffeine that can be formed in solutions under different conditions. Here, the oxidations of caffeine and isocaffeine in the presence of TiO₂ nanoparticles under ultraviolet (UV) irradiation are studied in different solvents [distilled water (dH₂O), phosphate-buffered saline (PBS), and ethanol] using ultraviolet-visible spectroscopy, ¹H NMR spectroscopy, and electrospray ionization mass spectrometry. When exposed to colloidal TiO₂ nanoparticles and UV light, both caffeine and isocaffeine undergo oxidations in PBS and dH₂O. Moreover, in both cases the rates of their oxidations are much higher in PBS than in dH₂O. However, neither caffeine nor isocaffeine undergoes catalytic oxidations in ethanol under otherwise similar conditions. Compared with caffeine and isocaffeine, their oxidized products exhibit higher cytotoxicity and genotoxicity towards ovarian cancer cells. On the other hand, caffeine and its oxidized species show higher cyto- and geno-toxicity than isocaffeine and its oxidized products, respectively. This latter result clearly indicates that the simple structural difference by one methyl group in the xanthine backbone of these molecules causes these two molecules to exhibit distinct antioxidative properties and unique biological activities.

Original language	English (US)
Pages (from-to)	27-36
Number of pages	10
Journal	BioNanoScience
Volume	4
Issue number	1
DOIs	https://doi.org/10.1007/s12668-013-0120-7
State	Published - Mar 1 2014

ASJC Scopus subject areas

Bioengineering
Biomedical Engineering

Keywords

Caffeine
Cytotoxicity
Genotoxicity
Isocaffeine
Ovarian cancer cells
Photo-induced oxidation
Titanium dioxide nanoparticles

Access to Document

https://doi.org/10.1007/s12668-013-0120-7

Cite this

@article{184d5979e6b8405f9a642a2c524e19f0,

title = "Nanostructured TiO2 Catalyzed Oxidations of Caffeine and Isocaffeine and Their Cytotoxicity and Genotoxicity Towards Ovarian Cancer Cells",

abstract = "Although caffeine is well-known as an antioxidant and a psychoactive stimulant, its antioxidative properties and biological activities under various conditions are still largely unknown. The same can be said about caffeine{\textquoteright}s isomer, isocaffeine, whose properties have been even less investigated. Furthermore, much remains unknown about the potential biological effects and anticancer properties of the oxidative products of caffeine and isocaffeine that can be formed in solutions under different conditions. Here, the oxidations of caffeine and isocaffeine in the presence of TiO2 nanoparticles under ultraviolet (UV) irradiation are studied in different solvents [distilled water (dH2O), phosphate-buffered saline (PBS), and ethanol] using ultraviolet-visible spectroscopy, 1H NMR spectroscopy, and electrospray ionization mass spectrometry. When exposed to colloidal TiO2 nanoparticles and UV light, both caffeine and isocaffeine undergo oxidations in PBS and dH2O. Moreover, in both cases the rates of their oxidations are much higher in PBS than in dH2O. However, neither caffeine nor isocaffeine undergoes catalytic oxidations in ethanol under otherwise similar conditions. Compared with caffeine and isocaffeine, their oxidized products exhibit higher cytotoxicity and genotoxicity towards ovarian cancer cells. On the other hand, caffeine and its oxidized species show higher cyto- and geno-toxicity than isocaffeine and its oxidized products, respectively. This latter result clearly indicates that the simple structural difference by one methyl group in the xanthine backbone of these molecules causes these two molecules to exhibit distinct antioxidative properties and unique biological activities.",

keywords = "Caffeine, Cytotoxicity, Genotoxicity, Isocaffeine, Ovarian cancer cells, Photo-induced oxidation, Titanium dioxide nanoparticles",

author = "Xiaoxi Huang and Anandarup Goswami and Xiaoxin Zou and Stephanie Hayes and Vatsal Shah and Tamara Minko and Zhimin Tao and Tewodros Asefa",

note = "Funding Information: Acknowledgments TA gratefully acknowledges the financial assistance of the US National Science Foundation (NSF) under grant nos. NSF DMR-0968937, NSF NanoEHS-1134289, NSF-ACIF, and NSF Special Creativity grant. Publisher Copyright: {\textcopyright} 2014, Springer Science+Business Media New York.",

year = "2014",

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doi = "https://doi.org/10.1007/s12668-013-0120-7",

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T1 - Nanostructured TiO2 Catalyzed Oxidations of Caffeine and Isocaffeine and Their Cytotoxicity and Genotoxicity Towards Ovarian Cancer Cells

AU - Huang, Xiaoxi

AU - Goswami, Anandarup

AU - Zou, Xiaoxin

AU - Hayes, Stephanie

AU - Shah, Vatsal

AU - Minko, Tamara

AU - Tao, Zhimin

AU - Asefa, Tewodros

N1 - Funding Information: Acknowledgments TA gratefully acknowledges the financial assistance of the US National Science Foundation (NSF) under grant nos. NSF DMR-0968937, NSF NanoEHS-1134289, NSF-ACIF, and NSF Special Creativity grant. Publisher Copyright: © 2014, Springer Science+Business Media New York.

PY - 2014/3/1

Y1 - 2014/3/1

N2 - Although caffeine is well-known as an antioxidant and a psychoactive stimulant, its antioxidative properties and biological activities under various conditions are still largely unknown. The same can be said about caffeine’s isomer, isocaffeine, whose properties have been even less investigated. Furthermore, much remains unknown about the potential biological effects and anticancer properties of the oxidative products of caffeine and isocaffeine that can be formed in solutions under different conditions. Here, the oxidations of caffeine and isocaffeine in the presence of TiO2 nanoparticles under ultraviolet (UV) irradiation are studied in different solvents [distilled water (dH2O), phosphate-buffered saline (PBS), and ethanol] using ultraviolet-visible spectroscopy, 1H NMR spectroscopy, and electrospray ionization mass spectrometry. When exposed to colloidal TiO2 nanoparticles and UV light, both caffeine and isocaffeine undergo oxidations in PBS and dH2O. Moreover, in both cases the rates of their oxidations are much higher in PBS than in dH2O. However, neither caffeine nor isocaffeine undergoes catalytic oxidations in ethanol under otherwise similar conditions. Compared with caffeine and isocaffeine, their oxidized products exhibit higher cytotoxicity and genotoxicity towards ovarian cancer cells. On the other hand, caffeine and its oxidized species show higher cyto- and geno-toxicity than isocaffeine and its oxidized products, respectively. This latter result clearly indicates that the simple structural difference by one methyl group in the xanthine backbone of these molecules causes these two molecules to exhibit distinct antioxidative properties and unique biological activities.

AB - Although caffeine is well-known as an antioxidant and a psychoactive stimulant, its antioxidative properties and biological activities under various conditions are still largely unknown. The same can be said about caffeine’s isomer, isocaffeine, whose properties have been even less investigated. Furthermore, much remains unknown about the potential biological effects and anticancer properties of the oxidative products of caffeine and isocaffeine that can be formed in solutions under different conditions. Here, the oxidations of caffeine and isocaffeine in the presence of TiO2 nanoparticles under ultraviolet (UV) irradiation are studied in different solvents [distilled water (dH2O), phosphate-buffered saline (PBS), and ethanol] using ultraviolet-visible spectroscopy, 1H NMR spectroscopy, and electrospray ionization mass spectrometry. When exposed to colloidal TiO2 nanoparticles and UV light, both caffeine and isocaffeine undergo oxidations in PBS and dH2O. Moreover, in both cases the rates of their oxidations are much higher in PBS than in dH2O. However, neither caffeine nor isocaffeine undergoes catalytic oxidations in ethanol under otherwise similar conditions. Compared with caffeine and isocaffeine, their oxidized products exhibit higher cytotoxicity and genotoxicity towards ovarian cancer cells. On the other hand, caffeine and its oxidized species show higher cyto- and geno-toxicity than isocaffeine and its oxidized products, respectively. This latter result clearly indicates that the simple structural difference by one methyl group in the xanthine backbone of these molecules causes these two molecules to exhibit distinct antioxidative properties and unique biological activities.

KW - Caffeine

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KW - Genotoxicity

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KW - Ovarian cancer cells

KW - Photo-induced oxidation

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