Antihistaminic and antianaphylactic activity of Bresol (HK-07), a herbal formulation

Objective: To study the antianaphylactic, antihistaminic and mast cell stabilization activity of Bresol (HK-07) in experimental animals. Materials and Methods: Experimental studies of Bresol (HK-07) were evaluated using Wistar rats and Duncan Hartley guinea pigs. The antianaphylactic activity of Bresol (HK-07) was investigated in rats using active anaphylaxis model. The effect of Bresol (HK-07) on mast cell stabilization was performed by ex vivo challenge of antigen in sensitized rat intestinal mesenteries. Antihistaminic activity was studied in guinea pigs using histamine-induced bronchospasm where pre-convulsive dyspnea was used as an end point following exposure to histamine aerosol. Dose response studies of Bresol (HK-07) were conducted at 125, 250 and 500 mg/kg p.o. in anaphylactic shock-induced bronchospasm in rats. The optimal dose level was used for the remaining experimental models. Results: Treatment with Bresol (HK-07) at 125, 250 and 500 mg/kg p.o. showed a significant reduction in signs and severity of symptoms (p<0.05), onset (p<0.001) and mortality rate (p<0.05) following anaphylactic shock-induced bronchospasm. It also significantly reduced the serum IgE levels (p<0.001) in animals administered with Bresol (HK-07) as compared to untreated controls. Treatment of sensitized animals with Bresol (HK-07) at a dose rate of 500 mg/kg p.o. for 2 weeks resulted in a significant reduction in the number of disrupted mast cells (p<0.001) when challenged with an antigen (horse serum). Bresol (HK-07) significantly prolonged the latent period of convulsion (p<0.008) as compared to control following exposure of guinea pigs to histamine aerosol. Conclusion: The findings from various studies reveal that the antihistaminic and antianaphylactic activity of Bresol (HK-07) may be due to the mast cell stabilizing activity, suppression of IgE and inhibition of pathological effect induced by release of inflammatory mediators by some of the components of the herbal formulation.