Acute Oral Toxicity Study of Indigofera Tinctoria L. Aqueous Extract, a Substitute for Synthetic Food Colorants: Fourier Transform Infrared Spectroscopy, Biochemical, and Histopathological Investigation

Background and Purpose: This research aimed to investigate the in vivo acute oral toxicity of aqueous extract of Indigofera tinctoria L. in different doses in Wistar rats. Materials and Methods: Twenty-five male rats were divided into five groups (n=5 for each group). Group I served as the control, and the other four groups received I. tinctoria (100, 250, 500, and 1000mg/kg body weight) for 14 days. At the end of the experiment, all animals were killed, and the blood samples were collected for biochemical assay. The fourier transform infrared spectroscopy (FTIR), and histopathological analyses were done on different tissues. Results: According to the results, rats who received I. tinctoria (100mg) had lower triglyceride than the control group. Moreover, I. tinctoria administration in all groups did not change the serum glucose, creatinine, urea, and high-density lipoprotein amounts. In addition, using 100mg of the extract resulted in a lower alanine transaminase level than the control. Also, histopathology data indicated no signs of tissue toxicity and degeneration in all experimental groups. Furthermore, FTIR indicated that I. tinctoria had not changed the tissues’ protein structure. Conclusion: It can be concluded that I. tinctoria can be used as colorant food up to 1000mg/kg body weight.