D-Limonene, a natural cyclic terpene, is an agonistic ligand for adenosine A(2A) receptors.
Limonene is a major aromatic compound in essential oils extracted from citrus rind. The application of limonene, especially in aromatherapy, has expanded significantly, but its potential effects on cellular metabolism have been elusive. We found that limonene directly binds to the adenosine A(2A) receptor, which may induce sedative effects. Results from an in vitro radioligand binding assay showed that limonene exhibits selective affinity to A(2A) receptors. In addition, limonene increased cytosolic cAMP concentration and induced activation of protein kinase A and phosphorylation of cAMP-response element-binding protein in Chinese hamster ovary cells transfected with the human adenosine A(2A) receptor gene. Limonene also increased cytosolic calcium concentration, which can be achieved by the activation of adenosine A(2A) receptors. These findings suggest that limonene can act as a ligand and an agonist for adenosine A(2A) receptors.
Park HM, Lee JH, Yaoyao J, Jun HJ, Lee SJ. Limonene, a natural cyclic terpene, is an agonistic ligand for adenosine A(2A) receptors. Biochem Biophys Res Commun. 2011 January Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, South Korea.