Miltirone
Miltirone, also known as rosmariquinone, is an alkaloid found in plants such as Salvia rosmarinus and Salvia miltiorrhiza. It is a diterpene quinone, a group of compounds that are also known as tanshinones.
Pharmacology
The drug is a nonbenzodiazepine GABAA receptor positive allosteric modulator, binding to the benzodiazepine allosteric site of the receptor complex with a relatively low affinity of 300nM and acting as a partial agonist. It was orally active in animals and produced anxiolytic-like effects, but in contrast to diazepam, did not produce acute muscle relaxant effects and did not cause dependence or withdrawal with chronic administration. As a tanshinone, miltirone is structurally distinct from other known benzodiazepine receptor ligands.Development
Miltirone was first described in the scientific literature by 1970. It was isolated and described in red sage by 1970 and in rosemary by 1985. The GABAA receptor potentiation of miltirone was described in 1991. The drug was under formal pharmaceutical development by Abbott Laboratories for the treatment of anxiety disorders, but development was discontinued.Synthetic analogues of miltirone with greater potency as GABAA receptor positive allosteric modulators have been developed and reported.