Metanil yellow as a coloring agent is widely used in food industry to make food more appealing, appetizing and informative. Regulatory organization like FDA maintains strict rules but in our country coloring agents are at randomly used. This study is designed to evaluate side effects of metanil yellow on central nervous system and gastrointestinal tract in mice. Open field, hole board and hole cross tests were done to evaluate the effects of central nervous system; while castor oil and magnesium sulfate induced diarrheal tests were done to observe the effects on gastrointestinal tract. The mice were administered a dose of 5 gm/kg body weight of metanil yellow considered as 1x dose (MTYx) and another dose of 20 gm/kg body weight of metanil yellow considered as 4x dose (MTY4x). In the study, the metanil yellow exhibited central nervous system stimulatory effects based on hole cross test (p=000***, p=.003**, p=000***, p=.001***), hole board test (p=.03*, p=.005**, p=.041*, p=0.018*), and open field test (p=0.004**, p=.002**, p=.002**, p=.011*, p=0.008*). On the other hand gastrointestinal test results failed to show a significant effect (p=.04*). Jahangirnagar University J. Biol. Sci. 8(1): 35-44, 2019 (June)

Medicinal plants are frequently used in traditional medicine and about 80% peoples of developing countries use this traditional therapy to treat their ailments. Bombax insigne (Sw.). K. Shcum is a large deciduous tree, locally known as Bon or Pahari shimul or Tula gachh. The present study was designed to investigate the antioxidant and hepatoprotective potential of ethanolic extract of B. insigne fresh bark. In-vivo antioxidant activity tests were performed by determining the lipid peroxidation and catalase concentration of the homogenized liver of Swiss albino rats receiving two doses (1.5 and 3 gm/kg body weight) of the plant extract with 750 mg/kg body weight of paracetamol. For liver function tests (LFT), total 35 rats were taken and divided into five groups containing seven animals in each. Group I received distilled water; group II received only paracetamol. Group III received paracetamol with silymarin. Group IV and V both were treated with paracetamol along with two doses of B. insigne extract. To evaluate the hepatoprotective potential, seven liver test markers such as total protein, albumin, total bilirubin, alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and gamma-glutamyltransferase (GGT) of rats were considered. Test’s result for antioxidant activity demonstrated that the plant extract could inhibit the level of lipid peroxidation (LPO) induced by paracetamol. Enhancement of the level of the antioxidant enzyme catalase (CAT) was also observed. Paracetamol-induced hepatotoxicity in rats, as judged by the raised total protein, albumin, total bilirubin, serum enzymes, ALT, AST, ALP, GGT, were significantly prevented by the treatment with the extracts at different doses, demonstrating the hepatoprotective action of B. insigne. Histopathological observation also confirmed the hepatoprotective potential of B. insigne. Livers those were challenged with paracetamol exhibits the dishevelment of normal hepatic cells with centrilobular necrosis, inflammatory encroachment of lymphocytes and fatty changes were significantly protected by plant extract. The results of the present study suggested that B. insigne has antioxidant and hepatoprotective potential.