[Effects of thunberginol A contained in Hydrangeae dulcis forium on types I-IV allergies]

The inhibitory actions of thunberginol A on anti-allergic (type I-IV) activity were examined. Oral administration of thunberginol A 2 hr before the challenge significantly inhibited the PCA reaction (type I) in rats at a dose of more than 300 mg/kg and the ear PCA reaction in mice at a dose of more than 50 mg/kg. Thunberginol A at a dose of more than 300 mg/kg also significantly inhibited the allergic bronchoconstriction in rats. Thunberginol A concentration-dependently (10(7)-10(-4), 10(-5)-10(-4) M) inhibited the allergic contractions of rat trachea sensitized with IgE and those of the guinea pig lung preparation sensitized with IgG. It also inhibited the allergic histamine release from sensitized peritoneal exudate cells in a concentration-dependent manner (10(-5)-10(-4) M). Thunberginol A had anti-serotonic activity on the contraction of smooth muscle, and it increased the ear vascular permeability in mice. Thunberginol A significantly inhibited the primary response of contact dermatitis (type IV) in mice at 100 mg/kg from the day after immunization to the day before challenge, and it also inhibited the delayed type foot pad swelling in mice at a dose of more than 300 mg/kg at 0 and 8 hr after the challenge. These findings suggest that orally administered thunberginol A is effective against type I and type IV allergy.