Suppressive effect of Oren-gedoku-to (Huang-Lian-Jie-Du-Tang) on the production of superantigen by Staphylococcus aureus

Background: It is well known that Staphylococcus aureus (S. aureus) proliferates on the moist skin lesion of atopic dermatitis. Reduction of S. aureus from skin lesions by antibacterial agent has been reported to be effective for the treatment of atopic dermatitis. S. aureus produces superantigens which can activate T cells and possibely enhance the inflammatory reaction. Decrease of superantigens from S. aureus could cause the remission of atopic dermatitis. Oren-gedoku-to, an oral Japanese kampo medicine has been used for the treatment of atopic dermatitis. However, little is known about the mechanism of action of Oren-gedoku-to for therapy of atopic dermatitis. The purpose of this study was to investigate the effect of Orengedoku-to on the production of superantigens by S. aureus isolated from atopic dermatitis patients. Methods: Oren-gedoku-to was added to the suspension of S. aureus at lower doses than minimal inhibitory concentration, and incubated 4 hrs with 100 strokes per min. After incubation, the amounts of superantigens in the supernatant were measured using ELISA kit. Results: The production of superantigens was decreased by Oren-gedoku-to in a dose-dependent manner. Conclusions: The present study seems to suggest that clinical effectiveness of Orengedoku-to in the treatment of atopic dermatitis is due partly to it's suppressive effect on superantigen production.