Safety assessment of freeze-dried powdered Cassiae Semen: evaluation of chronic toxicity (26-week) in Sprague-Dawley rats

There is a lack of safety assessment data regarding the long-term consumption of Cassiae Semen (Leguminosae, the seeds of Cassia obtusifolia L. and Cassia tora L.). Thus, we evaluated the toxicity of freeze-dried powdered Cassiae Semen in male and female Sprague-Dawley rats. Rats were intragastrically administered freeze-dried powdered Cassiae Semen at a dose of 0.5, 2.2, or 10.0 g/kg body weight/day for 26 weeks; several variables were assessed after 13 and 26 weeks as well as after a 4-week recovery period. No mortality was observed in the treated animals, and body weight increased in a dose-dependent manner. The total bilirubin (TBIL) levels also displayed a dose-dependent relationship. In males, at 26 weeks, there were significant increases in relative kidney weights in the 2.2 and 10.0 g/kg groups compared with that in the negative control group (p < 0.05 or p < 0.01). Pigment deposition in the epithelial cells of the renal proximal convoluted tubules and atrophy or regeneration of renal tubules were observed in the 10.0 g/kg group after 26 weeks, and these changes were not fully reversed after the 4-week recovery period. Under the studied conditions, the primary toxicity organs for freeze-dried powdered Cassiae Semen in the 10.0 g/kg group were the kidneys.