Abstract

The present study aimed to investigate the relationships between the chemical structure and spasmolytic activity of 10 p-menthane monoterpene esters found in aromatic plants. All of the monoterpenes studied had spasmolytic actions in isolated guinea pig ileum. The neo-isopulegyl acetate and the 4-terpinyl acetate were the most potent, while the perillyl acetate was the least potent p-menthane ester. This difference in potency may be due to the position of the acetate group linked to C-7 in perillyl acetate, a structural feature different from that of the other esters. Our results revealed that stereochemistry and electronic density highly influenced spasmolytic activity in smooth muscle. Moreover, the presence of an aromatic ring or changes in the position of the ethyl acetate group in the p-menthane skeleton had little effect on the spasmolytic activity of monoterpene esters. Therefore, our data suggest that appropriate modifications of monoterpene structure can be associated with improved potency and may lead to the development of new antispasmodic drugs.

Key words: Monoterpene, essential oils, spasmolytic activity, smooth muscle, pharmacological activity.