Banca de QUALIFICAÇÃO: DÉLIS GALVÃO GUIMARÃES

DEVELOPMENT OF NAPHTOXAZOLES FROM PLANT ORIGIN NAPHTOQUINONE AND EVALUATION OF ITS APPLICABILITY

 AS A FLUORESCENT DNA PROBE.

DNA detection. Fluorescence. Naphthoxazole.

DNA detection by electrophoresis is a common technique in molecular biology laboratories. Ethidium bromide (EB) is often used as a DNA fluorescent probe in agarose gel electrophoresis. However, BE is mutagenic, requiring special handling, transport and disposal conditions, which increases its cost of use. Thus, it becomes necessary to research new fluorescent DNA probes with less risk of toxicity to human health and the environment. This study aimed to synthesize, establish the molecular structure and evaluate the applicability of new naphthoxazoles derived from naphthoquinone of plant origin as a fluorescent DNA probe. The compounds were obtained by semi-synthesis using lapachol as a starting reagent via the Debus-Radziszewski reaction in a one-pot process. The structures of naphthoxazoles were elucidated through the combined analysis of 1D and 2D Nuclear Magnetic Resonance (NMR) spectra. Naphthoxazoles were evaluated for interaction with DNA by UV-Vis spectroscopy. DNA binding studies were performed by monitoring changes in the absorption properties of naphthoxazoles in the absence and presence of dsDNA at different concentrations in 5% DMSO/Tris-HCl buffer (pH 7.4). The results of this study showed that the three naphthoxazoles (1 – 3) exhibit interaction behavior with DNA, due to changes in the absorption properties of these compounds against increasing concentrations of DNA. The results obtained suggest that naphthoxazoles 1 and 3 interact with DNA by external contact, more specifically by binding to grooves, and that naphthoxazole 2 binds to DNA by intercalation between base pairs. Naphthoxazole 2 exhibited a marked hypochromic rate of 23.39%, in addition to a significant red shift of 9 nm in the presence of increasing amounts of DNA. These results show that naphthoxazoles 1 – 3 are potential candidates for use as fluorescent DNA probes. Other studies in this direction are in progress.