Figure 2.

Encapsulation of curcumin into exosomes can increase curcumin's solubility and stability in vitro. (a) Exosomal curcumin is more soluble in phosphate-buffered saline (PBS) than free curcumin. An identical amount of curcumin was mixed with an equal volume of PBS or exosomes. Representative spectrographs of curcumin (Cur) and exosomal curcumin (exosomal cur) in the supernatant are shown, and the spectrographs were obtained using a Nanodrop 1000 spectrophotometer at OD₄₂₀. (b) Exosomal curcumin is more stable than free curcumin. Curcumin and exosomal curcumin were added to 2 ml PBS to achieve a final concentration of 30 µmol/l and incubated in the dark in a 37 °C water bath. At 30, 60, 90, 120, and 150 minutes, 100 µl of each sample was taken to determine the concentration of curcumin. The concentrations of curcumin or exosomal curcumin at the beginning were set as 1.00. The fold reduction of the concentration at each time point compared to the beginning is shown. The experiments were repeated three times for each time point (*P < 0.05, **P < 0.01).