Drug & Device Development

Herbal derivative shown to accelerate bilirubin clearance in mice

Last Updated: 2004-01-09 14:22:11 -0400 (Reuters Health)

NEW YORK (Reuters Health) - A compound derived from the Chinese herb Yin Chin activates the androstane receptor (CAR) and thereby increases the clearance of bilirubin from the liver, biologists at Baylor College of Medicine report. The findings suggest that "CAR is a potential target for the development of new drugs to treat neonatal, genetic, or acquired forms of jaundice."

Writing in the Journal of Clinical Investigation for January, the Houston-based team explains that Yin Zhi Huang, which contains extracts of Yin Chin (Artemisia capillaries) and three other plants, is used in Asia to prevent and treat neonatal jaundice.

To investigate the mechanism of action of these herbs, senior investigator Dr. David D. Moore and colleagues administered a tea of Yin Zhi Huang to wild-type and CAR-knockout mice for 3 days, then performed a bilirubin clearance assay. In wild-type but not the CAR-null mice, the tea significantly increased 1-hour bilirubin clearance in a dose-dependent manner.

After showing that CAR is required for Yin Zhi Huang to affect bilirubin levels, the scientists repeated the procedure in mice expressing human CAR in the liver, using Yin Zhi Huang and Yin Chin separately. Both concoctions increased bilirubin clearance.

Finally, they examined the role of two compounds present in Yin Chin, the coumarin 6,7-dimethylesculetin (scoparone) and 4'-hydroxyacetophenone in primary hepatocytes from wild-type mice and humanized CAR mice. Scoparone increased nuclear CAR expression, similar in effect to that of Yin Chin.

"It is intriguing that Artemisia species related to Yin Chin (e.g., wormwood, absinthe, mugwort, and tarragon) have been used in traditional medicines from many cultures for a variety of indications, including liver ailments," Dr. Moore's team notes. These agents also have hepatoprotective effects in animal models.

And in a related commentary, Dr. Mitchell A. Lazar calls it "very exciting if a pure compound emerges from the tea leaves as a pharmacological therapy for neonatal jaundice that is complementary or alternative to the current Western practice of phototherapy." Dr. Lazar is an endocrinologist at the University of Pennsylvania School of Medicine in Philadelphia.

J Clin Invest 2004;113:23-25,137-143.