Ku-Shen (Sophora flavescens Ait) has been used for treating asthma in the practice of Traditional Chinese medicine (TCM) and Hawaiian herbal medicine. It is one of the major components in our anti-asthma herbal formula, MSSM-002. The purpose of this study was to investigate the pharmacological actions of Ku-Shen (KS) in a murine model of allergic asthma.

AKR/J mice (n=7-10 per group) were sensitized intraperitoneally twice and challenged 3 times intratracheally at 7-10 days intervals with conalbumin. KS was administered intragastrically 24 hours after the first challenge, and then twice daily for 17 days. The effects of KS on airway hyperreactivity (AHR), eosinophilic inflammation, IgE levels and Th2 production in vitro were determined.

At the equivalent standard human adult dose, KS eliminated the development of AHR. Twice the usual dose (KS-2x) also significantly reduced airway inflammation as compared with the sham-treated group (13 ± 3 vs 43 ± 3%, p<0.01). Furthermore, serum IgE and Th2 cytokine levels (IL-4 and IL-5) in splenocyte cultures of KS-2x treated mice were significantly lower than the sham-treated group (p<0.01). No evidence of liver or kidney toxicity was observed at the doses used.

KS suppressed allergic airway responses, reduced inflammation and down-regulated Th2 responses. These findings lend support to the anecdotal findings of Hawaiian and TCM practice that KS is of value in the treatment of asthma. Further studies are required to determine whether KS alone or with other herbs can be a useful alternative or complementary therapy in modern asthma treatment.