A 90-day subchronic oral toxicity study of triterpene-enriched extract from Alismatis Rhizoma in rats

Alismatis Rhizoma has been used in East Asia as a traditional treatment for various illnesses and symptoms, and the presence of protostane-type triterpenes has been claimed to provide health benefits. To investigate the subchronic toxicity of triterpene-enriched extract from Alismatis Rhizoma (TEAR), a 90-day oral toxicity study was conducted in rats. Sprague–Dawley rats were randomly divided into four groups (10 rats/sex/group) and received doses of 0, 360, 720, and 1440 mg/kg/d of TEAR for 90 days. Daily clinical observations as well as weekly measurement of body weight and food consumption were conducted. Blood samples were obtained on day 91 to measure changes in hematology and biochemistry. Urine samples were collected on days 0 and 91 for urinalysis. At necropsy, selected organs were weighed and recorded, and histological examination was performed. No mortality or obvious treatment-related clinical signs, hematology, urinalysis parameters, and macroscopic or microscopic examinations were observed. Differences in weight gain, food consumption, biochemistry, and relative organ weight between the treated group and the control group were not considered treatment-related. On the basis of these findings, the no-observed-adverse-effect level for TEAR was 1440 mg/kg/d in both sexes.