Inhibititory Activity of Flavonoid Acetates on the Histamine Release from IgE-Sensitized Mast Cells

Flavonoids are the large class of plant-derived polyphenolic compounds with a broad spectrum of biological actions including anti-inflammatory, anti-allergic and anti-asthmatic activities. It has been reported that quercetin and some other flavonoids inhibit the histamine release from mast cells. Disodium cromoglycate, a kind of biflavonoid, have been used as a anti-asthmatic agent. Therefore, the following study was undertaken to characterize tile structure-activity relationships of flavonoids in the inhibition of histamine release, from IgE-sensitized mast cells. Flavonoid acetate were synthesized by addition of acetic anhydride to the flavonoids dissolved in pyridine. According In the Mota method, IgE-rich serum was made in rats sensitized with Pertussis vaccine and ovalbumin. Rat abdominal mast cells were harvested and purified over tile discontineous Percoll gradients, Mast cells were preincubated in RPMI with IgE-rich serum and further incubated with flavonoids. Histamine contents released from mast cells were determined fluorospectrophotometrically after stimulation with ovalbumin. (omitted)