title: Role of caffeine in DNA recognition of a potential food-carcinogen benzo[a]pyrene and UVA induced DNA damage.
abstract: Electron transfer (ET) reactions are important for their implications in both oxidative and reductive DNA damages. The current contribution investigates the efficacy of caffeine, a xanthine alkaloid in preventing UVA radiation induced ET from a carcinogen, benzo[a]pyrene (BP) to DNA by forming stable caffeine-BP complexes. While steady-state emission and absorption results emphasize the role of caffeine in hosting BP in aqueous medium, the molecular modeling studies propose the energetically favorable structure of caffeine-BP complex. The picosecond-resolved emission spectroscopic studies precisely explore the caffeine-mediated inhibition of ET from BP to DNA under UVA radiation. The potential therapeutic activity of caffeine in preventing DNA damage has been ensured by agarose gel electrophoresis. Furthermore, time-gated fluorescence microscopy has been used to monitor caffeine-mediated exclusion of BP from various cell lines including squamous epithelial cells, WI-38 (fibroblast), MCF-7 (breast cancer) and HeLa (cervical cancer) cells. Our in vitro and ex vivo experimental results provide imperative evidences about the role of caffeine in modified biomolecular recognition of a model carcinogen BP by DNA resulting dissociation of the carcinogen from various cell lines, implicating its potential medicinal applications in the prevention of other toxic organic molecule induced cellular damages.
authors.affiliation: Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata, 700 098, India.
authors.forename: Soma
authors.initials: S
authors.lastname: Banerjee
authors.forename: Siddhi
authors.initials: S
authors.lastname: Chaudhuri
authors.forename: Anup Kumar
authors.initials: AK
authors.lastname: Maity
authors.forename: Partha
authors.initials: P
authors.lastname: Saha
authors.forename: Samir Kumar
authors.initials: SK
authors.lastname: Pal
mesh_terms: D001564:Benzo(a)pyrene / Q000737:chemistry*; D002110:Caffeine / Q000737:chemistry*; D045744:Cell Line, Tumor; D004249:DNA Damage; D006367:HeLa Cells; D006801:Humans; D061986:MCF-7 Cells; D008958:Models, Molecular; D010084:Oxidation-Reduction; D013057:Spectrum Analysis; D014466:Ultraviolet Rays
chemical_list: D001564:Benzo(a)pyrene; D002110:Caffeine
keywords: benzo[a]pyrene (BP); breast cancer (MCF-7) cells and HeLa cells; caffeine; co-exposure to UVA radiation and BP; fibroblast (WI-38) cells; fluorescence microscopy; inhibition of electron transfer (ET) reaction; picosecond-resolved fluorescence of BP; prevention of DNA fragmentation; squamous epithelial cells