Abstract:

A quadratic orthogonal rotary composite design was used to optimize the extraction of anthocyanins from
blueberry with respect to five process parameters including ethanol concentration, material-to-liquid ratio, solvent pH,
temperature and time, and the proliferative effect of the extracted anthocyanins on spleen cells as well as the synergistic
effect when combined with ConA on promoting the secretion of interferon-a (IFN-α) and interleukin-2 (IL-2) in mouse
spleen cells was evaluated by in vitro cultivation. The results showed that the extraction efficiency for blueberry was
significantly affected by ethanol concentration, material-to-liquid ratio, temperature and time. The optimal extraction conditions
were found to be 74.6%–76.2% ethanol as extraction solvent with a material-to-liquid ratio of 1:6.6–1:6.8 (g/mL) for 144.8–
148.5 min of extraction at pH 3.0–3.1 and 52.5–53.4 ℃. Under these conditions, the yield of anthocyanidins extracted
from blueberry was more than 35 mg/g. The blueberry anthocyanins could significantly promote the proliferation of
spleen cells and cooperate with ConA to accelerate the production of TNF-α and IL-2 in normal mouse spleen cells in
a dose-dependent way.

Key words: blueberry, anthocyanin, orthogonal rotation combination design, immunomodulatory activity