Ameliorative Effects of Methanolic Extract of Sennaalata leaves on Streptozotocin (Stz)-Induced Oxidative Stress and Hepatotoxicity in Adult Wistar Albinorats

: Introduction: Sennaalata leaf is widely available in the tropics and has very important applications in folkloric medicine. It contains several biological properties and antioxidant properties. In the northern part of Nigeria, particularly in Adamawa and Taraba States, the root, stem and leaves are used by practitioners of herbal medicines to treat burns, skin and wound infections, diarrhea, gastrointestinal and upper respiratory tract infections. Objectives: In this work, liver morphology was studied, markers of hepatic oxidative stress and some liver enzymes in STZ-induced rats treated with methanolic extract of Sennaalata leaves. Methods: Oxidative stress was induced in fasted male wistar rats with intraperitoneal injection of Streptozotocin (STZ). A total of 40 wistar rats were used for this study. The animals were randomly divided into four groups of 10 animals per group. The experimental period was three weeks beginning after the induction of STZ-induced oxidative stress. Group A: normal untreated rats. Group B: STZ-induced untreated group (60mg/kg body weight). Group C and D were STZ-induced rats given methanolic extract of Sennaalata leaves (150mg/kg and 300mg/kg body weight) daily using an intragastric tube for three weeks(21 days). Results: The result of this study showed that administration of streptozotocin (STZ) to rats resulted in significant decrease (P <0.05) in the activity of Superoxide dismutase (SOD) and concentration of reduced glutathione (GSH) as well as significant increase (P <0.05) in malondialdehyde (MDA) concentration when compared with the control group. However, simultaneoustreatment of STZ –induced groups(groups C and D) with 150mg/kg and 300mg/kg body weight of methanolic extract of Sennaalata leaves produced a significant increase (P <0.05) in Superoxide dismutase(SOD) activity and reduced gluthathione(GSH) concentration, and a significant decrease (P < 0.05) in malondialdehyde (MDA) concentration as compared with the STZ-induced untreated group. The result of the present study also showed a marked elevation in the activities of serum marker enzymes, alanine transaminase (ALT) and aspartate transaminase(AST) in the STZ – induced group when compared with the normal control group. Nonetheless, treatment of STZ-induced groups(group C and group D) with methanolic extract of Sennaalata leaves significantly decreased (p <0.05) the activities of ALT and AST when compared with STZ-induced untreated group(group B). The histological section of STZ-induced untreated group showed enlarged central vein, periportal fatty infiltration (PFI) with focal necrosis of hepatocytes. Conversely, the histological section of the liver of the rats induced with STZ and simultaneously treated with 300mg/kg methanolic extract of Sennaalataleaves depicted normal hepatocytes with normal morphology and without necrosis. Conclusion: These observations therefore, suggest that methanolicextract of Sennaalata leaves possess antioxidant andhepatoprotective effect against STZ effects,wistar albino rats. and the acts against free radical-induced oxidative stress involved by different defense mechanism like