Phenolic diterpenes from rosemary suppress cAMP responsiveness of gluconeogenic gene promoters.

The cAMP/protein kinase A/cAMP response element (CRE)-binding protein pathway is important for various physiological aspects including regulation of gluconeogenic gene expression. Rosemary, a well-known herb, has been reported to decrease blood glucose levels. We found that methanol extracts of rosemary suppressed forskolin (FSK)-stimulated luciferase expression under the control of CRE, as well as the promoters for cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) and glucose-6-phosphatase (G6Pase) catalytic subunit genes in human hepatoma HepG2 cells.