Pinitol (3- O-methyl- D- CHIRO-inositol)
Pinitol is a natural product of the group of cyclitols.
D-pinitol attenuates the impaired activities of hepatic
key enzymes in carbohydrate metabolism of streptozotocin-induced diabetic rats.
Gen Physiol Biophys. 2009; Sivakumar S. Department of Biochemistry, University of Madras, Tamilnadu, India.
During diabetes mellitus, endogenous hepatic glucose production is increased as a result of impaired activities of the key enzymes of carbohydrate metabolism, which leads to the condition known as hyperglycemia. D-pinitol, a bioactive constituent isolated from soybeans, has been shown to reduce hyperglycemia in experimental diabetes. We therefore designed this study to investigate the effect of oral administration of D-pinitol (50 mg/kg b. w. for 30 days) on the activities of key enzymes in carbohydrate and glycogen metabolism in the liver tissues of streptozotocin-induced diabetic rats. The efficacy was compared with glyclazide, a standard hypoglycemic drug. Oral administration of D-pinitol to diabetic group of rats showed a marked decrease in the levels of blood glucose, glycosylated hemoglobin and an increase in plasma insulin and body weight. The activities of the hepatic enzymes such as hexokinase, pyruvate kinase, glucose-6-phosphate dehydrogenase, glycogen synthase and hepatic glycogen content were significantly increased whereas the activities of glucose-6-phosphatase, fructose-1,6-bisphosphatase, lactate dehydrogenase and glycogen phosphorylase were significantly decreased in diabetic rats treated with D-pinitol. The results suggest that alterations in the activities of key metabolic enzymes of carbohydrate metabolism could be one of the biochemical rationale by which D-pinitol attenuates the hyperglycemic effect in diabetic rats.
Effects of Acute Pinitol Supplementation on Plasma
Pinitol Concentration, Whole Body Glucose Tolerance, and Activation of the
Skeletal Muscle Insulin Receptor in Older Humans.
Horm Metab Res. 2009. Stull AJ, Wood KV, Thyfault JP. Department of Foods and Nutrition and Center on Aging and the Life Course, Purdue University, West Lafayette, IN, USA.
Limited research with rodents and humans suggests that oral ingestion of pinitol might positively influence glucose tolerance. This double-blinded, placebo-controlled, and cross-over study assessed the effects of acute pinitol supplementation on plasma pinitol concentration, glucose tolerance, insulin sensitivity, and activation of the skeletal muscle insulin receptor. Fifteen older, nondiabetic subjects completed four, 1-day trials. Subjects consumed a non-nutritive beverage with nothing (placebo) or 1 000 mg pinitol. Sixty minutes later, the subjects consumed beverages that were either energy- and carbohydrate-free (Sham) or contained 75 g glucose (OGTT). For the OGTT trials only, vastus lateralis samples were obtained before the placebo and pinitol supplementation and 60 min after consuming the 75 g glucose beverage. Plasma pinitol concentration increased and was maintained for 240 min. Pinitol did not influence the fasting state and 180-min area under the curves for plasma glucose and insulin during the Sham and OGTT trials or hepatic and whole-body insulin sensitivities. Activation of the muscle insulin receptor was increased by 140% with glucose ingestion but pinitol did not influence this response. Pinitol supplement was quickly absorbed, but did not acutely influence indices of whole-body glucose tolerance and insulin sensitivity, or the activation of the skeletal muscle insulin receptor in older, nondiabetic humans.
Metabolic response of soy pinitol on lipid-lowering,
antioxidant and hepatoprotective action in hamsters fed-high fat and high
Mol Nutr Food Res. 2009. Department of Food Science and Nutrition, Kyungpook National University, Daegu, Korea.
This study was performed to investigate the lipid-lowering, antioxidant, and hepato-protective effects of pinitol in dose-dependent manners in hamsters fed-high fat and high cholesterol (HFHC) diet. Pinitol supplementation with an HFHC diet (10% coconut oil plus 0.2% cholesterol) for 10 wks significantly lowered the white adipose tissue weights, hepatic lipid droplets, plasma glucose, total-cholesterol, nonHDL-cholesterol, total-cholesterol/HDL-cholesterol ratio, and hepatic lipid levels. Whereas it significantly increased the brown adipose tissue weight, plasma HDL-cholesterol, apolipoprotein A-I (apo A-I) concentrations, paraoxonase (PON) activity, and/or mRNA expression, compared to the HFHC control group. Plasma insulin and adiponectin levels were significantly lower and higher. Dietary pinitol significantly inhibited hepatic HMG-CoA reductase, acyl-CoA:cholesterol acyltransferase (ACAT), and cytochrome P4502E1 (CYP2E1) activities without altering their mRNA expressions compared to the control group. Pinitol significantly elevated the hepatic antioxidant enzyme activities, whereas it also significantly reduced the hepatic lipid peroxide and H(2)O(2) production. Accordingly, these results indicate that pinitol supplementation may improve the lipid and antioxidant metabolism in HFHC diet-fed hamsters. In particular, pinitol supplementation was very effective on the elevation of antiatherogenic factors, including plasma HDL-cholesterol, apo A-I, adiponectin, and PON.
Pinitol is found in
Acacia nilotica herb
Pinitol is found in an aqueous extract of the heartwood of Enterolobium cyclocarpum
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