Prevention of allergen-induced bronchial obstruction in sensitized guinea pigs by crude alcoholic onion extract.

Thirteen guinea pigs, sensitized to ovalbumin, were pretreated with either 1 ml alcoholic onion extract (= 12% v/v ethanol) or 1 ml 12% ethanol solution (control) according to a randomized crossover protocol. Thirty minutes later the animals were challenged twice for 30 sec (n = 5), respectively 60 sec (n = 8), by the inhalation of ovalbumin (1 ml 1% ovalbumin solution nebulized in 10 l air). The intensity of bronchial obstruction was measured by whole body plethysmography using as parameter the amount of 'compressed air'. Oral pretreatment of guinea pigs with onion extract markedly reduced the asthmatic response (p less than 0.02). After onion pretreatment near normal values were obtained after 30 sec challenge (0.04 +/- 0.06 ml compared to 0.24 +/- 0.15 ml in the control) and only slightly increased values after 60 sec challenge (0.16 +/- 0.07 ml compared to 0.33 +/- 0.25 ml in the control).