The effect of a plants mixture extract on liver gluconeogenesis in streptozotocin induced diabetic rats

We have previously reported on plant mixture extract comprising of Nigella sativa, Myrrh, Gum Olibanum, Gum Asafoetida and Aloe to have a blood glucose lowering effect. The present study with streptozotocin diabetic rats is focussed on the mechanism of action, specifically on a) hepatic gluconeogenesis b) activity of key gluconeogenic enzymes, pyruvate carboxylase (PC) and phosphoenol-pyruvate carboxykinase (PEPCK). Similar studies using a biguanide, phenformin, have been conducted to compare the mode of action of these two compounds. The blood glucose levels (mean +/- SEM) before and after treatment with the plants extract were (16.7 +/- 1.7 mmol/L and 8.5 +/- 1.3 mmol/L) and with phenformin (15.1 +/- 1.3 mmol/L and 10.7 +/- 1.5 mmol/L). The rate of gluconeogenesis in isolated hepatocytes as well as activity of PC and PEPCK in liver homogenates is significantly lowered following treatment with the plants extract. Although phenformin also lowers blood glucose, it does not affect hepatic gluconeogenesis under stated experimental conditions. It is concluded that the anti-diabetic action of the plants extract may, at least partly, be mediated through decreased hepatic gluconeogenesis. The extract may prove to be a useful therapeutic agent in the treatment of non-insulin dependent diabetes mellitus (NIDDM).