Obiajulu Christian Ezeigwe
1* 
, Daniel Nnaemeka Onwusulu
2 , Chukwuemeka Steve Adindu
1 , Chukwudi Onyeaghana Okani
3 , Maryclare Ebubechukwu Onuegbu
1 1 Department of Applied Biochemistry, Faculty of Biosciences, Nnamdi Azikiwe University Awka, Anambra State, Nigeria
2 Department of Obstetrics and Gynaecology, Faculty of Medicine, College of Health Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria
3 Department of Histopathology, Chukwuemeka Odumegwu Ojukwu University, Awka Campus, Anambra State, Nigeria
Abstract
Introduction: Diabetes mellitus is a common global cause of sudden unpredictable death if undiagnosed and untreated. Costus afer (Costaceae) is a tropical plant with quite a lot of pharmacological properties. This study investigated the prophylactic and antidiabetic properties of ethyl acetate fraction of C. afer in streptozotocin-induced diabetic rats. Methods: Acute toxicity (LD50) test was done using Lorke’s method. Haematological indices were determined using haematology autoanalyser. The biochemical assays were done using standard diagnostic methods. Results: The lethal dose was 3807.9 mg/kg. There was a significant reduction (P < 0.05) in the fasting blood glucose concentration from week one to week four in the group that was pre-treated and later post-treated with 200 mg/kg body weight (bw) of the ethyl acetate fraction of C. afer leaves compared with the untreated diabetic control. The result of the hematological parameters revealed a significant increase (P < 0.05) in the hemoglobin, packed cell volume (PCV), and platelet count of the group pretreated and treated with 200 mg/kg of the fraction compared with the untreated diabetic control. The result of the biochemical assays revealed a far much better recovery from the disruptions caused by the induction of experimental diabetes as seen in the groups that were initially pretreated with 100 and 200 mg/kg before the induction of diabetes compared with the groups treated with the same dose but without pretreatment. Conclusion: C. afer might be used for the prevention and management of diabetes mellitus. Its safety is evidenced by its effects on the hematological and biochemical indices.