Hypoglycemic and antihyperglycemic effect of Ceiba pentandra L. Gaertn in normal and streptozotocin-induced diabetic rats.

BACKGROUND: Ceiba pentandra (L.) Gaertn, commonly called silk-cotton tree, has been extensively used by traditional medicine practitioners in Northern and Eastern Nigeria in the control and management of diabetes. OBJECTIVE: To evaluate the hypoglycaemic and anti-hyperglycaemic effect of ethanolic extract of Ceiba pentandra bark in normal and streptozotocin induced diabetic rats. METHOD: Screening activity of the extract was carried out by OGTT. Diabetes mellitus was induced with streptozotocin and graded doses of the ethanolic bark extract (200 and 400 mg/kg, b.w.) were then administered to the experimentally diabetic rats. The blood glucose level was measured at different time intervals. RESULTS: The single dose study of C. pentandra extract at two different doses produced no significant hypoglycaemic effect in normal rats but C. pentandra (200 mg/kg) significantly decreased blood glucose level in diabetic rats. In OGTT, C. pentandra (200 mg/kg) significantly reduced elevated glucose level in normal and diabetic rats. In long term (21 days) study, C. pentandra (200 mg/kg) significantly decreased blood glucose level, total cholesterol and triglycerides level, prevented degeneration of liver and pancreas, and increased serum insulin level and liver glycogen content in diabetic rats. Acute toxicity study in rats did not show any signs of toxicity up to the dose of 2000 mg/kg b.w. CONCLUSION: The results reveal that the extract improved glucose tolerance in normal and streptozotocin-induced diabetic rats. Thus the study suggests that the C. pentandra bark extract could be beneficial in the management of type I diabetes.

Nootropic activity of Celastrus paniculatus seed.

The effect of Celastrus paniculatus Willd. (Celastraceae) seed aqueous extract on learning and memory was studied using elevated plus maze and passive avoidance test (sodium nitrite induced amnesia rodent model). The aqueous seed extract was administered orally in two different doses to rats (350 and 1050 mg/kg) and to mice (500 and 1500 mg/kg). The results were compared to piracetam (100 mg/kg, p.o.) used as a standard drug. Chemical hypoxia was induced by subcutaneous administration of sodium nitrite (35 mg/kg), immediately after acquisition training. In elevated plus maze and sodium nitrite-induced amnesia model, Celastrus paniculatus extract has showed statistically significant improvement in memory process when compared to control. The estimation of acetylcholinesterase enzyme in rat brain supports the plus maze and passive avoidance test by reducing acetylcholinesterase activity which helps in memory performance. The study reveals that the aqueous extract of Celastrus paniculatus seed has dose-dependent cholinergic activity, thereby improving memory performance. The mechanism by which Celastrus paniculatus enhances cognition may be due to increased acetylcholine level in rat brain.

Antihistaminic and mast cell stabilizing activity of Striga orobanchioides.

The ethanolic and aqueous extracts of the whole plant of S. orobanchioides were evaluated for antihistaminic and mast cell stabilizing activities. Both extracts inhibited histamine-induced contractions of the guinea-pig ileum at the concentration range of 2.5-25 microg/ml in a dose-related manner. At 25 microg/ml, both extracts inhibited the response of histamine (0.5 microg/ml) almost completely. The effect of these two extracts on the degranulation rate of sensitized peritoneal cells of albino rats when challenged with antigen (horse serum) was studied. Triple vaccine was used as adjuvant. Ketotifen and prednisolone were used for comparison. The ethanolic extract at 100 and 200 mg/kg body weight was found to significantly inhibit degranulation of mast cells to an extent of 52.14+/-3.24 and 67.96+/-3.70%, respectively. At the same doses, the aqueous extract showed 42.09+/-2.91 and 60.67+/-3.50% reduction in degranulation of mast cells, respectively. Hence, both extracts markedly protected the rats against antigen-induced challenge of mast cells.