Role of Cyclic Nucleotide System in the Action of Oriental Medicinal Herbs

Abstract

Tests were performed on mice in order to examine the ability of Oriental medicinal herbs to increase plasma levels of cyclic AMP in vivo. Cyclic AMP was determined by radioimmunoassay before and after administration of water decocted extracts of 218 different herbs. Of these,82 were positive. Polyphenol, a tannin-like substance, was responsible for most of the activities of the herbs except Platycodi Radix. The active constituents in Platycodi Radix were successfully purified and were shown to be saponins. Further, tannic acid and its degenerates, pyrogallol and purpurogallin, which are produced by peroxidase from pyrogallol, were shown to have adenylate cyclase stimulatory, COMT inhibitory and phosphodiesterase inhibitory activities, respectively. Peroxidase activities were varied according to the mouse strain, suggesting that the efficacy of Oriental medicinal herbs is determined by the interaction between the herbs and the metabolism of the patient. Long term peroral administration of Shôseiryû-tô which has been used for bronchial asthma, enhances the plasma cyclic AMP responses to isoprenaline and histamine in mice and restores the down regulation induced by long term subcutaneous injections of catecholamine, indicating that there is some effect on the β-adrenoceptors and H2 receptors. Evodiae Fructus contains 30-40n mole/g dry wt. cyclic GMP and Zizyphi Fructus contains 30-50 and 100-500n mole/g dry wt. cyclic GMP and cyclic AMP, Respectively. In natural occurrance, these values are the highest among not only plants but also animal tissues. Chronic and general pharmacological action by Oriental medicinal herbs can be explained partly via its effect on the cyclic nucleotide system.