Figure 3.

Effect of polyphenolic antioxidants on histamine release by antigen–IgE-activated mast cells. Mast cells were sensitized with 2 µg/ml IgE in the presence of different concentrations of rutin/CGA for 24 hr in duplicate cultures. Cells were washed, resuspended in Tyrode's buffer (135 mm KCl, 1 mm MgCl₂, 1·8 mm CaCl₂, 5·6 mm glucose, and 20 mm HEPES, pH 7·4), and incubated with 100 ng/ml DNP-BSA for 1 hr at 37°. Two hundred µl supernatant was then taken from the duplicate cultures. Levels of histamine were determined against the standard curve according to a quantitative histamine RIA kit obtained from Biomerica Inc. (Newport Beach, CA). Approximately 30% histamine was released in supernatants (350 ± 70 ng/10⁶ cells) of antigen-IgE activated control mast cells. Four such experiments were performed for different doses of antioxidants.