Nicotiana Tabacum Aqueous Leaf Extract Elicits Hepato-renal and Nuerotoxicity in Rats

Abstract

Nicotiana tabacum (Tobacco) has been in use for several years among the human race all over the world, It has been reported to be responsible for more deaths than any other herb globally. Tobacco is used in difference ways but cigarettes constitute the largest share of the manufactured tobacco products in the world. The toxicological evaluation of medicinal plants is essential to ensure their safe use. Therefore, this study investigates the hepatic, renal and neurotoxic potentials of Nicotiana tabacum aqueous leaf extract in Wistar rats. A total of forty- eight (48) healthy male rats were separated into two groups with twenty-four rats per group. Each animal in the first group labelled control, was given 1ml of distilled water only as treatment while each animal in the second group was treated with tobacco leaf extract at a concentration of 25 mg/kg body weight. All the animals were exposed to the same chow and water throughout the experiment. The treatments were given daily for 12 weeks. At 4 weeks, 8 animals were sacrificed from each of the groups. Then at 8 weeks, 8 animals from each group were also sacrificed while the remaining animals were sacrificed at the end of the 12 weeks. Serum biochemical indices, oxidative stress parameters, and histopathological alterations in liver, kidney, and brain tissues were assessed. Results indicated cumulative increases in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), Bilirubin, urea, and creatinine levels, from week 4 through week 12; suggesting hepatocellular and renal damages. Decreased brain nitric oxide and antioxidant enzyme levels, along with increased malondialdehyde concentration, BCL-2, p53 and caspase 9 levels indicated oxidative and neurotoxic stress. Histological evaluation revealed hepatic necrosis, tubular degeneration, and neuronal vacuolation. These findings suggest that Nicotiana tabacum aqueous leaf extract induces dose- dependent hepatic, renal and neuro-toxicities in rats, underscoring the need for caution in the use of tobacco in traditional medicine. The implications of tobacco abuse are far reaching and have serious consequences for individuals and the society at large. Negative outcomes of tobacco abuse include mental disorders, social violence, gang formation, cultism, armed robbery, internet fraud and lawlessness among youths. Abuse of tobacco hampers academic performance and motivation and can also lead to physical and psychological dependence resulting in school dropouts. It is therefore suggested that tobacco be classified as other street drugs of abuse.