Antihyperglyceamic Effect of N-Hexane Fraction of Lepidagathis Alopecuroides Leaves in Alloxan Induced Diabetic Rats

Abstract

Lepidagathis alopecuroides (Vahl) is a tropical shrub belonging to the family Acanthaceae commonly found in the coastal countries of West Africa. The leaves are used to immobilize fish in many communities of Rivers and Cross River States of Nigeria. The present study was carried out to investigate the antihyperglycemic activity of the n-hexane leaf fraction of L. alopecuroides in alloxan induced diabetic rats. A total of eighteen adult mice were used to determine the LD50, while a total of 24 adult Wister rats where used for the evaluation of the antidiabetic effect of the fraction. The animals were divided into six groups, with each group containing 4 rats. Group 1 was the normal control, group 2 was the positive control, group 3 was the standard control, and group 4, 5, and 6 received 100, 200 and 400 mg/kg b.w of the n-hexane leaf fraction respectively. Their blood glucose and insulin levels were assayed. Their serum samples were analyzed after 2 weeks of treatment, to ascertain the alkaline phosphatase (ALP), alanine aminotranferase (ALT) aspartate aminotranferase (AST) superoxide dismutase (SOD) and catalase (CAT) activities. Malondialdehyde (MDA), reduced glutathione (GSH), creatinine and urea serum levels were also tested. Lipid profile (total cholesterol, TAG, LDL and HDL) as well as some haematological indices (RBC, WBC, Hb, and PCV), and the histology of the pancreas were also investigated. The phytochemical screening of the plant leaf showed that alkaloids, terpenoids, flavonoids, and saponins were abundantly present while phenols and tannins were moderately present. Glycosides were slightly present. The LD50 of the extract showed no mortality. The body weight of the animals in the treated diabetic groups as well as in the normal control group significantly increased by day 14 when compared to positive control group. The result of the study on blood glucose as well as insulin level revealed that the leaf fraction caused a significant (p < 0.05) reduction in hyperglycemia relative to the positive control group. A significant (p < 0.05) decrease in insulin level was observed in positive control group when compared to normal control. In contrast, both standard control and the groups that received graded doses of leaf fraction showed a significant (p < 0.05) increase in insulin level when compared to positive control. Generally, there were significant (p < 0.05) decrease in the activities of ALP, AST, and ALT in the treatment groups when compared to the untreated group. Urea and Creatinine concentration significantly (p < 0.05) reduced in the treatment groups when compared to positive control. There were significant (p < 0.05) reduction in MDA concentration of the groups that received 200 and 400 mg/kg of leaf fraction when compared to untreated groups. CAT, SOD and GSH level in treatment groups were significantly (p < 0.05) higher when compared to positive control. LDL, TAG, and total cholesterol significantly (p < 0.05) decrease in the treatment groups when compared to positive control. However, HDL on the other hand increased significantly (p < 0.05) in treatment groups when compared to positive control.WBC, RBC, HB and PVC significantly (p < 0.05) increased in the treatment groups when compared to positive control. Histology of positive control showed a marked decrease in the number and sizes of pancreatic islets. The islet cells showed a vacuolar degeneration and necrosis, swollen with foamy cytoplasm and eosinophilic necrotic debris when compared to normal control, which showed the normal histomorphology of the endocrine pancreas. There was also a reduction in the number and sizes of pancreatic islets in group 3 and 4. However, group 5 and 6 showed a marked proliferation of the α-cells in the pancreatic islets with less abundant β-cells. The results of this study showed that the n-hexane leaf fraction of Lepidagathis alopecuroides significantly reduced the hyperglycemia in alloxan-induced diabetic rats and also restored some altered haematological indices as well as some biochemical parameters in alloxan-induced diabetic rats. The investigation possibly authenticates the use of L. alopecuroides leaf fraction in folkloric treatment of diabetes and its associated complication.