Analysis of fluorescence spectra of citrus polymethoxylated flavones and their incorporation into mammalian cells

Authors: GONCALVES, DANIELLE - Sao Paulo State University (UNESP); Manthey, John; DA COSTA, PAUL - Sao Paulo State University (UNESP); RODRIGUES, MARILIA C.M. - Sao Paulo State University (UNESP); CESAR, THAIS - Sao Paulo State University (UNESP)

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2018
Publication Date: 7/9/2018
Citation: Goncalves, D.R., Manthey, J.A., Da Costa, P.I., Rodrigues, M., Cesar, T.B. 2018. Analysis of fluorescence spectra of citrus polymethoxylated flavones and their incorporation into mammalian cells. Journal of Agricultural and Food Chemistry. 66:7531-7541. https://doi.org/10.1021/acs.jafc.8b02052.
DOI: https://doi.org/10.1021/acs.jafc.8b02052

Interpretive Summary: There is a class of compounds in orange juice that help promote good health in people. These compounds show fluorescence when exposed to ultraviolet light. The characteristics of the fluorescence depends on the chemical structure of each different compound and the environment that these compounds occur. These compounds are demonstrated to bind to specific locations in human cells by the use of fluorescence microscopy.

Technical Abstract: Citrus polymethoxylated flavones (PMFs) influence biochemical cascades in human diseases, yet little is known of their cellular associations and how these associations influence the actions of these compounds. An innate attribute of PMFs is their ultraviolet light-induced fluorescence, and the fluorescence spectra of fifteen PMFs and seven PMF metabolites were measured in solution, and for a subset of these the fluorescence spectra were also measured bound to human carcinoma Huh7.5 cells. Similarities occurred in the fluorescence spectra of PMFs and their glucuronidated metabolites, either dissolved in methanol or bound to cells, but emission wavelength maxima of PMF metabolites with free phenyl hydroxyls exhibited 70-80 nm red shifts when bound to the Huh7.5 cells. Notable solvent effects were observed for nearly all these compounds, and these influences likely reflect the effects of localized microenvironments on the electronic structures and spectra of these compounds when bound to human cells.