In vitro (?-Glucosidase and ?-Amylase Inhibition) and in vivo Antidiabetic Property of Phytic Acid (IP₆) in Streptozotocin-Nicotinamide-Induced Type 2 Diabetes Mellitus (NIDDM) in Rats

Abstract

Phytic acid, inositol hexaphosphate (IP6) a natural plant constituent and antioxidant exhibits protective action in carcinogenesis, Alzheimer's, hypercholesterolemia, diabetes and inflammations when taken in diet. The aim of this study is to evaluate effect of phytic acid in streptozotocin (STZ)-nicotinamide-induced type 2 diabetes in rats. The STZ-nicotinamide induced diabetic rats were orally treated with vehicle (2%w/v Tween 80), glimepiride (2.5 mg/kg) and IP6 (650 mg/kg) for 28 days. The blood glucose level, body weight, glycosylated haemoglobin (HbA1C), lipid profile, lipid peroxidation, antioxidant status (liver and small intestine) was measured and compared with control. Xanthine dehydrogenase (XDH) and xanthine (XO) activity was measured in small intestine of diabetic rats. In vitro inhibition of carbohydrate digestive enzymes (α-glucosidase and α-amylase) was also determined. IP6, significantly (P<0.01) reduced glucose level, HbA1C, lipid profile and lipid peroxidation, and increased body weight, high density lipoprotein level and antioxidant status in liver and small intestine. Decrease in XO and increase in XDH activity was observed in treatment groups compared to diabetic control. Dose dependent inhibition of α-glucosidase and (α-amylase activity was observed for phytic acid when compared to standard drug acarbose. These results clearly indicate that IP6 possess promising in vitro and in vivo antidiabetic activity.

In Vivo and In Vitro Antidiabetic Activity of Terminalia paniculata Bark: An Evaluation of Possible Phytoconstituents and Mechanisms for Blood Glucose Control in Diabetes

“…A 1000  μ L of 96 mM DNS reagent was added to the above solution, and the contents were heated for 15 min on a boiling water bath. The final volume was made up with distilled water, and the absorbance was measured at 540 nm using spectrophotometer [14]. The percentage inhibition and 50% inhibitory concentration (IC 50 ) value was calculated.…”

“…To stop the α -glucosidase action on maltose, the above reaction mixture was kept in boiling water for 2 min and cooled. To this, 2 mL of glucose reagent was added and its absorbance was measured at 540 nm to estimate the amount of liberated glucose by the action of α -glucosidase enzyme [14]. The percentage inhibition and 50% inhibitory concentration (IC 50 ) value was calculated.…”

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“…[31] It was determined by incubating100 µl of α-glucosidase enzyme (1 U/ml) solution with100 µl of phosphate buffer (pH 7.0) which contains 100 µl of enzyme inhibitor such as acarbose (6.25-100 µg/mL) at 37°C for 60 min in maltose solution. To stop the α-glucosidase action on maltose, the above reaction mixture was kept in boiling water for 3 min and cooled.…”

Evaluation of possible mechanisms of three plants for blood glucose control in diabetes

“…The boiling stops the -glucosidase action on maltose. Glucose reagent (2 mL) was added and absorbance is measured at 540 nm to estimate the amount of liberated glucose by the action of -glucosidase (Kuppusamy et al, 2011) Glucose uptake in normal and streptozotocin-induced diabetic rats…”