Antiasthmatic Effects of Galphimia glauca, Gallic Acid, and Related Compounds Prevent Allergen- and Platelet-Activating Factor-Induced Bronchial Obstruction as well as Bronchial Hyperreactivity in Guinea Pigs

Abstract

A methanolic extract from Galphimia glauca (320 mg/kg, orally) inhibited acute bronchial reactions to allergen (ovalbumin, 10 mg/ml) and platelet-activating factor (PAF, 1 μg/ml) inhalation challenges, but not to histamine or acetylcholine in spontaneously breathing guinea pigs. Furthermore, the PAF-induced bronchial hyperreactivity was markedly reduced. Gallic acid and related compounds as well as the flavonoid, quercetin, were identified as active compounds. Gallic acid, methyl gallate and quercetin showed significant effects after a single oral dose of 45 mg/kg, tetragalloyl quinic acid after 5 mg/kg. Continuous treatment of the animals with one certain fraction (GG II, 3 days, 3 × 2 mg/kg) containing all active compounds reduced allergen- and PAF-induced bronchial reactions by more than 70%.