Indirubin

Psoriasis is a common, chronic skin disease for which only remissive, as opposed to curative, treatments are available. Traditional Chinese medicine is one of the most frequently chosen alternative therapies in China and Taiwan, and psoriasis has been treated for centuries with topical and oral herbal preparations. Topical indigo naturalis ointment has been reported to exhibit potential anti-psoriatic efficacy. The study objective is to investigate pharmacological effect and explore targeting mechanisms of Traditional Chinese Medicine (TCM) Indigo Naturalis topical ointment as a single treatment agent in Chinese subjects with mild to moderate plaque-type Psoriasis.
This was a single site, randomized, double-blinded, placebo controlled study of topical indigo naturalis vs. vehicle alone (placebo) to treat mild to moderate plaque-type psoriasis during an 8-week period. Pharmacological effect will be evaluated by biomarker evaluation and clinical evaluation. The trial was conducted at the China Medical University Hospital (CMUH), Taichung, Taiwan. All patients provided written informed consent before inclusion in the study. The study protocol was approved by the institutional review board (IRB) of CMUH.

The use of refined indigo naturalis (indigo naturalis extract in oil, INEO)ointment to treat psoriasis has been proven effective in our previous study. This study aims to evaluate the efficacy and safety of INEO ointment, and further determine the optimal concentration of INEO ointment (per gram of ointment containing either 200 μg, 100 μg, 50 μg or 10 μg of indirubin) in treatment of various local skin signs and thickness of psoriasis plaque.