Curcumin, as the main ingredient of the curcuma spice, has increasingly become the target of scientific
research. The turmeric root where the spice is obtained from has been widely used in the traditional medicine.
Moreover, scientific studies have found that curcumin has anti-inflammatory, anti-cancer, anti-angiogenic effects
as well as antibacterial properties. Recently, curcumin has gathered interest as a potential therapeutic agent in the
research on Alzheimer’s disease.
A consistent problem in the investigative and therapeutic applications of curcumin is its poor solubility in aqueous
In the present study, we synthesized a conjugate of curcumin, the amino acid lysine and the fluorescent dye fluorescein.
This conjugate was soluble in cell culture medium and facilitated the examination of curcumin with fluorescence
We studied the cell growth impact of unmodified curcumin on seven different human cell lines and then analyzed
the uptake and cellular localization of our curcumin conjugate with confocal laser scanning imaging and flow
cytometry on the seven cell lines.
We found that unbound curcumin inhibited cell growth in vitro and was not taken up into the cells. The curcumin
conjugate was internalized into the cell cytoplasm in a dot-like pattern and cellular uptake correlated with the cell
membrane damage which was measured using propidium iodide.
The CAL-72 osteosarcoma cell exhibited 3-4fold increased conjugate uptake and a strong uniform fluorescein
staining in addition to the dot-like pattern observed in all cell lines.
In conclusion, we successfully synthesized a novel water-soluble fluorescent curcumin conjugate which showed a
strong preference for CAL-72 osteosarcoma cells in vitro.