Oral baicalin and liquid extract of licorice reduce sorbitol levels in red blood cell of diabetic rats.

Intracellular accumulation of sorbitol, resulting from the increased glucose flux through polyol pathway with the action of aldose reductase, has been found pathogenic to chronic diabetic complications. It has been reported that baicalin and Glycyrrhiza uralensis Fisch can inhibit rat lens aldose reductase in vitro. In order to determine whether the said medicinal herbs give the inhibitive effect in vivo, 10 streptozotocin induced diabetic rats were treated with baicalin 150 mg/kg.d and liquid extract of licorice (LEL) 7.5 ml/kg.d for a week. RBC sorbitol was determined by a fluorometric assay before and after the treatment, as well as one week afterwards. It was found that oral baicalin and licorice dramatically reduced sorbitol levels in RBC without affecting blood glucose levels. The sorbitol levels was restored to its original values one week after discontinuing the treatment. The present study has demonstrated the effectiveness of baicalin and licorice in reducing RBC sorbitol levels in diabetic rats. Its mechanism is presumably through inhibition of aldose reductase. The feasibility of its clinical application for the control of diabetic complications is under investigation.