Hypoglycaemic activity of Bixa orellana extract in the dog.

In West Indian folklore, a variety of plants are used for medicinal purposes. One such plant, Bixa orellana (annatto), is commonly used in the treatment of diabetes mellitus. Preliminary studies have shown that a crude annatto seed extract exhibited either glucose lowering or hyperglycaemia-inducing activity depending on how it was further manipulated. This present investigation sought to determine the effects of the glucose-lowering extract on C-peptide and streptozotocin-induced diabetic dogs. This annatto extract was found to decrease blood glucose levels in fasting normoglycaemic and streptozotocin-induced diabetic dogs. In addition, in normal dogs, it suppressed the postprandial rise in blood glucose after an oral glucose load. Interestingly, the extract also caused an increase in insulin-to-glucose ratio in normal dogs. Increased insulin levels were not due to increased insulin synthesis as after 1-h residence time and half-hour postprandial, decreased C-peptide levels was observed. It was concluded that Bixa orellana (annatto) lowered blood glucose by stimulating peripheral utilization of glucose, and it is possible that this glucose-lowering extract might be of pharmacological importance.

Changes in some liver enzymes in streptozotocin-induced diabetic rats fed sapogenin extract from bitter yam (Dioscorea polygonoides) or commercial diosgenin.

The effects of steroidal sapogenin extract from bitter yam or commercial diosgenin on liver enzyme changes were investigated Diabetic male Wistar rats were fed diets supplemented with 1% steroidal sapogenin extract or commercial diosgenin for three weeks. Plasma glucose levels and the activities of hepatic glucose-6-phosphatase, pyruvate kinase and glucose-6-phosphate dehydrogenase were assessed Liver total cholesterol, HDL-cholesterol and total phospholipid were also measured. Plasma glucose decreased significantly (p < 0.05) in diabetic rats fed the three test diets compared to the diabetic control. The three test diets significantly decreased glucose-6-phosphatase activity compared to the diabetic control The activities of ATP-citrate lyase, pyruvate kinase and glucose-6-phosphate dehydrogenase were significantly reduced in the liver of diabetic rats compared to normal control. Supplementation of the diet with bitter yam steroidal sapogenin extract or commercial diosgenin did not significantly alter ATP citrate lyase and pyruvate kinase activities but significantly increased glucose-6-phosphate dehydrogenase activity in the liver compared to diabetic rats. This study shows that the feeding of the two test diets to diabetic rats results in alterations in the metabolism of glucose with subsequent reduction in plasma glucose concentration.

The effect of phytic acid on the levels of blood glucose and some enzymes of carbohydrate and lipid metabolism.

In this study, six groups of rats were fed as follows: Groups 1 and 2 were fed formulated diets supplemented with zinc or without zinc respectively. Groups 3 and 4 were fed formulated diets supplemented with zinc plus phytic acid extracted from sweet potato (Ipomea batatas) or commercial phytic acid respectively. Groups 5 and 6 were fed formulated diets supplemented with phytic acid extract from sweet potato or commercial phytic acid respectively. The animals were fed for three weeks and then sacrificed The activities of key enzymes of carbohydrate and lipid metabolism as well as transaminases in the liver were determined. Blood glucose level was also assessed. Phytic acid extract consumption from sweet potato and commercial phytic acid plus zinc supplement lowered blood glucose levels. There was no significant change in the activity of 6-phosphogluconate dehydrogenase among the groups. Similarly, phytic acid supplementation showed no significant decrease in the activity of pyruvate kinase compared to the group fed formulated diets. There was a significant increase in the activity of glucose-6-phosphate dehydrogenase in the groups fed phytic extract from sweet potato compared to the other groups. The activities of malic enzyme and ATP-citrate lyase in this study were not significantly altered among the groups. There is a lowering of blood glucose levels which is desirable for diabetics who consume sweet potato diets. The changes in some of the hepatic metabolic enzymes are geared towards compensating for the decreased glycolytic responses.

Changes in some liver enzymes in streptozotocin-induced diabetic rats fed sapogenin extract from bitter yam (Dioscorea polygonoides) or commercial diosgenin / Cambios en Algunas Enzimas Hepáticas en ratas con Diabétes Inducida Mediante Estreptozotocina, Alimentadas con Extracto de Sapogenina de ñame Amargo (Dioscorea polygonoides) o Diosgenina Comercial

The effects of steroidal sapogenin extract from bitter yam or commercial diosgenin on liver enzyme changes were investigated Diabetic male Wistar rats were fed diets supplemented with 1 steroidal sapogenin extract or commercial diosgenin for three weeks. Plasma glucose levels and the activities of hepatic glucose-6-phosphatase, pyruvate kinase and glucose-6-phosphate dehydrogenase were assessed Liver total cholesterol, HDL-cholesterol and total phospholipid were also measured. Plasma glucose decreased significantly (p < 0.05) in diabetic rats fed the three test diets compared to the diabetic control. The three test diets significantly decreased glucose-6-phosphatase activity compared to the diabetic control The activities of ATP-citrate lyase, pyruvate kinase and glucose-6-phosphate dehydrogenase were significantly reduced in the liver of diabetic rats compared to normal control. Supplementation of the diet with bitter yam steroidal sapogenin extract or commercial diosgenin did not significantly alter ATP citrate lyase and pyruvate kinase activities but significantly increased glucose-6-phosphate dehydrogenase activity in the liver compared to diabetic rats. This study shows that the feeding of the two test diets to diabetic rats results in alterations in the metabolism of glucose with subsequent reduction in plasma glucose concentration

Se investigaron los efectos del extracto de sapogenina esteroidal del ñame amargo o la diosgenina comercial, sobre los cambios enzimáticos del hígado. A ratas Wistar machos con diabetes les fueron suministradas dietas con suplementos de 1% de extracto de sapogenina esteroidal o diosgenina comercial por espacio de tres semanas. Se evaluaron los niveles de glucosa plasmática y las actividades de la glucosa-6-fosfatasa hepática, el piruvato kinasa y la glucosa-6-fosfato deshidrogenasa. Asimismo fueron medidos el colesterol total del hígado, el colesterol HDL y el fosfolípido total. La glucosa plasmática disminuyó significativamente (p < 0.05) en las ratas diabéticas a las que se les alimentó con las tres dietas de la prueba, en comparación con el control diabético. Las tres dietas de la prueba disminuyeron significativamente la actividad de la glucosa-6-fosfatasa en comparación con el control diabético. Las actividades de la ATP-citrato liasa, la piruvato kinasa y la glucosa-6-fosfato deshidrogenasa disminuyeron significativamente en el hígado de las ratas diabéticas, en comparación con el control normal. El suplemento dietético con extracto de sapogenina esteroidal de ñame amargo o la diosgenina comercial no alteró de manera significativa las actividades de la ATP-citrato liasa y la piruvato kinasa, pero aumentó significativamente la actividad de la glucosa-8-fosfato deshidrogenasa en el hígado, en comparación con las ratas diabéticas. Este estudio demuestra que la alimentación con las dos dietas de prueba suministrada a las ratas diabéticas, produce alteraciones en el metabolismo de la glucosa, con la consiguiente reducción de la concentración de glucosa plasmática

The effect of phytic acid on the levels of blood glucose and some enzymes of carbohydrate and lipid metabolism / El Efecto del ácido fítico sobre los niveles de la glucosa en sangre y sobre algunas enzimas del metabolismo de carbohidratos y lípidos

In this study, six groups of rats were fed as follows: Groups 1 and 2 were fed formulated diets supplemented with zinc or without zinc respectively. Groups 3 and 4 were fed formulated diets supplemented with zinc plus phytic acid extracted from sweet potato (Ipomea batatas) or commercial phytic acid respectively. Groups 5 and 6 were fed formulated diets supplemented with phytic acid extract from sweet potato or commercial phytic acid respectively. The animals were fed for three weeks and then sacrificed The activities of key enzymes of carbohydrate and lipid metabolism as well as transaminases in the liver were determined. Blood glucose level was also assessed. Phytic acid extract consumption from sweet potato and commercial phytic acid plus zinc supplement lowered blood glucose levels. There was no significant change in the activity of 6-phosphogluconate dehydrogenase among the groups. Similarly, phytic acid supplementation showed no significant decrease in the activity of pyruvate kinase compared to the group fed formulated diets. There was a significant increase in the activity of glucose-6-phosphate dehydrogenase in the groups fed phytic extract from sweet potato compared to the other groups. The activities of malic enzyme and ATP-citrate lyase in this study were not significantly altered among the groups. There is a lowering of blood glucose levels which is desirable for diabetics who consume sweet potato diets. The changes in some of the hepatic metabolic enzymes are geared towards compensating for the decreased glycolytic responses

En este estudio, se alimentaron seis grupos de ratas de la forma que a continuación se describe. Los grupos 1 y 2 fueron alimentados con dietas formuladas con o sin suplemento de zinc respectivamente. Los grupos 3 y 4 fueron alimentados con dietas formuladas con suplemento de zinc más ácido fítico extraído del boniato (Ipomea batatas) o el ácido fítico comercial respectivamente. Los grupos 5 y 6 fueron alimentados con dietas formuladas con suplemento de extracto de ácido fítico del boniato o ácido fítico comercial respectivamente. Los animales fueron alimentados durante tres semanas y luego sacrificados. Se determinó la actividad de las enzimas claves del metabolismo de carbohidratos y lípidos, así como las transaminasas en el hígado. Asimismo se evaluó el nivel de glucosa en sangre. El consumo de extracto de ácido fítico del boniato y el ácido fítico comercial más el suplemento de zinc, diminuyeron los niveles de glucosa en sangre. No hubo cambios significativos en la actividad de la 6-fosfogluconato deshidrogenasa entre los grupos. De modo similar, la suplementación con ácido fítico no mostró una disminución significativa de la actividad de la piruvato kinasa en comparación con el grupo alimentado con dietas formuladas. Sin embargo, hubo un aumento significativo en la actividad de la glucosa-6-fosfato deshidrogenasa en los grupos alimentados con extracto fítico de boniato en comparación con los otros grupos. No hubo alteración significativa de las actividades de la enzima málica y la ATP-citrato liasa en este estudio. Hay una disminución de los niveles de glucosa en sangre, deseable para los diabéticos que consumen dietas de boniato. Los cambios en algunas de las enzimas metabólicas hepáticas están encaminados a compensar la disminución de las respuestas glicolíticas.

Effect of yam (Dioscorea cayenensis) and dasheen (Colocassia esculenta) extracts on the kidney of streptozotocin-induced diabetic rats.

Streptozotocin-induced diabetic wistar rats were maintained for 4 weeks on a supplement of extracts of yam (Dioscorea cayenensis) or dasheen (Colocassia esculenta). The activities of malic enzyme, NADP+ isocitrate dehydrogenase, Glucose 6-P-dehydrogenase and the transaminases were determined to assess any degree of metabolic alteration caused by diabetic nephropathy. Diabetic rats fed normal diet and those fed yam extract, dasheen extract and commercial linamarin respectively lost weight significantly compared to healthy controls. The diabetic rats fed dasheen extract, maintained near normoglycaemic values compared to diabetic rats on normal diet (P < 0.05). Malic enzyme activity was significantly reduced (P < 0.05) in diabetic rats on the normal diet compared to normal healthy controls. Feeding of yam or dasheen extract raised the activity of this enzyme towards normal. Feeding of dasheen extract or commercial linamarin significantly lowered (P < 0.05) the activity of NADP+ isocitrate dehydrogenase below that of healthy controls. Glucose 6-P-dehydrogenase activity was significantly increased (P < 0.05) in diabetic rats compared to healthy controls. Alanine transaminase in the kidney of diabetic rats fed yam extract was significantly higher than healthy controls (P < 0.05). These results demonstrate an overall aggravation of the diabetic nephropathy by yam and dasheen extracts in the diet. In the Caribbean region where these foods are dietary staples, there may be a correlation with the reported high prevalence of diabetes mellitus and the development of renal disease.