Acute Toxicity of Quercetin From Onion Skin in Mice

Quercetin is the most abundant flavonoid molecule, is widely distributed in the plant kingdom, and has a wide range of uses.

This study aimed to determine the LD50 of quercetin from onion (Allium cepa) skin (QOS) and its effect on the livers and kidneys of mice. 

This study consisted of two phases. In phase one, 9 mice BALB/c were divided into three groups of three mice each. The mice in each group received QOS at 10 mg/kg, 100 mg/kg, and 1000 mg/kg, respectively, and were monitored for 24 h for any signs of toxicity or mortality. In phase two, three mice were divided into three groups of one mouse each. Each mouse received QOS at 1600 mg/kg, 2900 mg/kg, and 5000 mg/kg. The mice were observed for 24 h for any signs of toxicity or mortality. 

A significant increase was observed in serum albumin, total protein, and aspartate aminotransferase (AST) levels in mice that received 10 mg/kg, 100 mg/kg, and 1000 mg/kg QOS. A significant decrease in serum alkaline phosphatase (ALP), alanine aminotransferase (ALT), cholesterol, creatinine, urea, and the electrolyte was noticed in mice that received QOS at 10 mg/kg, 100 mg/kg, and 1000 mg/kg when compared with the control group. The livers of mice that received 1600 mg/kg and 2900 mg/kg QOS showed hemorrhage and enlarged sinusoids along with a distortion of the renal tubule and aggregation of lymphocytes within the kidneys. 

The LD50 of QOS was 3807 mg/kg in mice. QOS above 1000 mg/kg led to a distortion of the hepatocytes and renal tubule with an increase in serum AST, ALT, and creatinine, suggesting that QOS could be toxic at 1000 mg/kg and above.