Bowman-Birk inhibitor suppresses production of superoxide anion radicals in differentiated HL-60 cells

The Bowman-Birk protease inhibitor (BBI) is a soybean-derived pretense inhi bitor with anticarcinogenic and anti-inflammatory properties. BBI has previ ously been shown to suppress the release of superoxide superoxide anion rad icals from purified polymorphonuclear leukocytes. In the present study we e valuated the effect of BBI on the production of superoxide union radicals i n differentiated HL-60 cells. HL-60 cells are human lymphocytic cells that acquire neutrophil-like characteristics when treated with dimethyl sulfoxid e or tetradecanoyl phorbol acetate. Superoxide anion radical production by differentiated HL-60 cells was measured in the presence of various concentr ations of BBI or BBI concentrate, a soybean extract containing high levels of BBI. BBI was observed to suppress superoxide anion radical production by differentiated HL-60 cells in a dose-dependent manner. Extracts of differe ntiated HL-60 cells were also observed to produce superoxide anion radicals , but this activity was not affected by the presence of BBI. These results suggest that BBI inhibits superoxide anion radical generation in HL-60 cell s bur does not act as a simple free radical scavenger.