IN VITRO AND IN VIVO ANTIHYPERGLYCEMIC EFFECT OF ACTIVE FRACTION OF CLEOME RUTIDOSPERMA DC

Objective: The present study was aimed to investigate the possible mechanism of action of the active sub fraction of C. rutidosperma. This was done by in vivo and in vitro method.Methods: Aqueous extract of C. rutidosperma was sequentially fractionated and re-fractionated to yield the active sub fraction (based on in vivo evaluation). In the in vivo study, the active sub fraction was administered to streptozotocin-induced diabetic mice at graded doses in different prandial states; while for the in vitro method, assessment of the possible effects of the active sub fraction of the plant on glucose absorption by excised ileum as well as its effect on α-glucosidase, α-amylase and glucose 6 phosphatase activities was evaluated.Results: There was significant reduction of blood glucose level by the active sub fraction at different prandial states. The active sub fraction produced comparable hypoglycemic effects as glibenclamide. Likewise, at the doses of 125 and 62.5 mg/kg b. w., it significantly (p<0.05) reduced postprandial hyperglycemia after administration. Glucose tolerance was significantly (p<0.05) improved in the presence of the active sub fraction to varying degrees. The active sub fraction of C. rutidosperma did not demonstrate inhibitory effects on glucose movement into external solution across the rats excised ileum except at 50g/L and 25g/L where a significant (p<0.05) inhibition of glucose movement was observed. Alpha-amylase inhibitory activity of the active sub fraction was found to be 22. 24% at the lowest concentration of 2.50 mg/ml while the highest concentration of 20.00 mg/ml gave 46.66% inhibition. On the other hand, acarbose (standard) showed inhibition of 16.00 % and 34.43% for its lowest and highest concentrations for α-amylase respectively. Similarly, the α-glucosidase inhibitory activity results were: 16.42% and 44.56% for C. rutidosperma and acarbose respectively for the lowest concentration of 2.50 mg/ml, while the highest concentration of 20mg/ml had 64.22% and 87.09% for C. rutidosperma and acarbose respectively. Also, the active sub fraction of the plant showed significant inhibitory activity against glucose 6-phosphatase in a dose dependent fashion.Conclusions: The results revealed that the possible antihyperglycemic mechanism of action of the plant may be by reduction of postprandial hyperglycemia and improvement of glucose tolerance activity by stimulation of insulin secretion from pancreatic cell and inhibition of carbohydrate hydrolysing enzymes. Consequently, C. rutidosperma may be used as a dietary adjunct to counter hyperglycemia and it has the potential to be developed as new oral antidiabetic agent for the treatment of diabetes mellitus.Â

BIOASSAY-GUIDED EVALUATION OF THE ANTIDIABETIC ACTIVITY OF CLEOME RUTIDOSPERMA DC

Objective: An earlier anti-hyperglycemic study with crude extracts of Cleome rutidosperma indicated aqueous extract as the most effective. The present study was undertaken to in part identify the potent antihyperglycemic fraction from the aqueous extract of the plant, using bioassay guided fractionation.Methods: Aqueous extract of C. rutidosperma were fractionated to obtain chloroform, ethyl acetate, n-butanol, methanol and aqueous fractions, which were tested for antidiabetic activity using acute Streptozotocin-Induced diabetic mice model. Further fractionation of the more active methanol fraction yielded 1st sub-fractions I- IX. The more active of these 1stsub-fractions were further re-fractionated to give 2ndsub-fractions (2SFC1 and 2SFC2). The more active of the 2ndsub-fractions (2SFC1) was purified further using preparative thin layer chromatography (TLC) and the resultant fractions (TLCFIC and TLCFIIC) were tested in vivo.Results: The methanol fraction of C. rutidosperma significantly (p < 0.05) reduced blood glucose more than the other fractions, while the most active 1st sub-fraction from in vivo studies in mice was, chloroform: methanol (5: 5). Also, the more active of the 2ndsub-fractions was: 2SFC1. The preparative thin layer chromatography (TLC) results from in vivo studies indicated TLCFIC to be the most active.Conclusion: The observed antidiabetic activity of the plant may be as a result the phytoconstituent of the plant. Therefore the fractionated component could be a new source of development of new plant based therapy for management of diabetes.Â