The isoflavone genistein inhibits proliferation and increases histamine content in human leukemic mast cells.

Mast cells are involved in allergic inflammation and some rare disorders such as systemic mastocytosis and mast cell leukemia. Certain naturally occurring flavonoids have been shown to inhibit mast cell activation and promote maturation of secretory granules. Here, we report that the isoflavone genistein inhibited the growth of human leukemic mast cells (HMC-1) by 68.8, 51.6, and 30.2% at 10(-4), 10(-5), and 10(-6) M, respectively, at day 3 (p < 0.001). Genistein at 10(-4) M increased the histamine content per 2 x 10(5) cells at day 3 from 5.9 +/- 1.2 micrograms/mL to 11.1 +/- 1.3 micrograms/mL (n = 6; p < 0.0001). These results indicate that genistein can inhibit proliferation and induce maturation of HMC-1 cells.