Abstract:

The distribution of cyanidin-3-O-glucoside (C3G) in cultured mouse and human macrophages was detected
with fluorescence technique. First, the specific excitation wavelength and emission wavelength of C3G were scanned with
fluorescence spectrophotometric assay. Then, a confocal laser scanning microscopy was utilized to investigate the entry
process of C3G into cultured mouse macrophages and human macrophage THP-1 cells, and to trace the location of C3G as
well as the change in fluorescence intensity in the cells during incubation. The results showed that green and red fluorescence
in macrophages after 15 min C3G incubation could be detected with light excitation at 488 nm and 520 nm, respectively. The
fluorescence signals were enhanced in the cells as the incubation time was prolonged. The special fluorescence appeared in
nuclei when the cells were treated with C3G for 60 min, and the average fluorescence intensity was enhanced by 6.45 folds
when C3G incubation time was increased up to 60 min. These results indicated that the distribution of C3G in cells during
incubation could be traced with laser scanning confocal microscopy assay. It was concluded that C3G could pass rapidly
through the cell membrane and nuclear membrane of macrophages, and entered directly the cell nucleus.

Key words: cyanidin-3-O-glucoside, macrophages, confocal laser scanning microscopy, fluorescence spectrophotometric assay