AMELIORATION OF METABOLIC DERANGEMENT BY BIOACTIVE COMPOUNDS FROM Vernonia amygdalina IN STREPTOZOTOCIN-INDUCED DIABETES
Author: OJIEH Anthony Emeka
The search for herbal preparations with anti-diabetic properties continues to demand significant attention as the incidence of diabetes mellitus worldwide is on the increase despite all well-established treatment modalities. In recent times, herbal preparations are being recognized as a good source of medicinal formulations for diabetes mellitus management and in some instance as compliment therapy to existing anti-diabetic drugs. However, most of these herbal preparations are yet to be investigated fully with the sole aim of understanding how they the metabolism of carbohydrate, also to the extent of identifying the bioactive compounds in the herbal preparation with hypoglycemic properties. This study investigates the influence of bioactive components of Vernonia amygdalina extract on the management of diabetes mellitus. Fresh samples of bitter leaves having being air-dried, were crushed and soaked in ethanol for 48hours. The resultant mixture was sieved and allowed to stand for the ethanol to evaporate; the ethanol-free solution was subsequently subjected to liquid-liquid fractionation. Some fresh Vernonia amydgdalina leaves were also macerated and sieved to get a liquid crude extract. Adult male Wistar rats (150- 200gm) were randomly selected, 5 rats per group with a total of 12 groups (n=5). The grouping is as follows; 1a and 2a were control groups,1b, 1c, 1d, 1e and 1f (normoglycemic groups), and 2b, 2c, 2d, 2e, 2f served as the diabetic groups. Diabetes was induced in the rats by injecting streptozotocin at 60mg/kg as a single dose, intraperitoneally. The treatment groups were put on Vernonia amgydalina extract at 300mg/kg/day. Group 3, a comparative diabetic group was placed on metformin at 50mg/kg/day. Fasting glucose level and body weight of the rats were monitored weekly. At the expiration the treatment period (28days), the animals were sacrificed; blood samples were collected and centrifuged and the resulting serum obtained for biochemical analysis. The live were also harvested and part (0.5gm) homogenized for biochemical analysis. Data were analyzed using SPSS package and expressed as mean ± SEM. Results showed an upsurge glycolytic enzyme activity in rats treated with the crude extract (hexokinase 422.92±13.42µU/mg.liver), compared to untreated diabetic rats (328.56±38.82 µU/mg.liver) and increased pyruvate kinase activity (treated 668.30±11.95U/g.liver; untreated 304.98±20.76U/g.liver). There were also increased the pentose phosphate pathway enzymes activity observed with the plant treatment. The bitter leave demonstrated significant reduction in fasting glucose level (diabetic rats 307.40±12.18; VA 105.67±17.68; Metformin 204.67±152.11mg/dl), showed increase serum HDL level (Diabetic rats 38.06±2.08; VA 55.58±6.01; Metformin 43.65±7.64mg/dl), also showed reduction in liver enzyme ALP (VA 19.01±3.21; Diabetic rat 90.24±6.09; Metformin 18.97±8.50) and ALT (VA 17.99±6.35; Diabetic rats 133.12±5.43; Metformin 37.32±3.61U/L). Analysis of the plant with GC-MS, elucidated bioactive compounds with hypoglycaemic properties such as Phytol, Palmitic acid, stearic acid and oxirane. Bitter leaf in this study also promoted glycolytic and the pentose phosphate pathways which are alternate glucose metabolic pathways in a hyperglycaemic state. The plant may also ameliorate renal and liver complications associated with diabetes while improving lipid metabolism.
Supervisor: Prof. J.C. Igweh, Prof. C.P. Aloamaka