Plantago major L. Extracts Reduce Blood Glucose in Streptozotocin-Induced Diabetic Mice

Plantago major L. (P. major L.) is a perennial plant belonging to the family Plantaginaceae. It has been used as a folk remedy for diabetes in Europe and Asia. However, the biologically active constituents responsible for the antidiabetic effects have not been reported. The objectives of this study aimed at determining the chemical components of Plantago major L. and evaluating the antidiabetic activity of the extracts using streptozotocin- (STZ-) induced diabetic mice. In this study, the Swiss mice were fed a high-fat diet to gain weight before STZ injections to induce diabetic conditions. The STZ-induced diabetic mice were orally treated with P. major L. extracts. The blood glucose test results from the treated diabetic mice and nontreated diabetic mice were compared. We found that a 15-day treatment with EP6 extract from P. major L. at a dose of 400 mg/kg could reduce the blood glucose level to the same level as a 15-day treatment with glucophage at a dose of 70 mg/kg. The major chemical components and structural characterization of EP6 extract were also reported. AST (aspartate transferase) and ALT (alanine aminotransferase) indicators of liver damage were measured in the treated and nontreated diabetic mice to give an overall view of the antidiabetic effect of P. major L. extracts.