Analgesic effects of Ephedra herb and ephedrine alkaloids-free Ephedra herb extract (EFE)

Kampo medicines containing Ephedra Herb are used to treat pain arising owing to lumbago, stiff shoulder, arthralgia, and rheumatoid arthritis. The analgesic action of these Kampo medicines has been thought to be due to the antiinflammatory effect of ephedrine alkaloids present in Ephedra Herb. Meanwhile, Ephedra Herb has several side effects, induced by ephedrine alkaloids such as hypertension, palpitations, insomnia, and dysuria. Therefore, both the pharmacological actions and adverse effects of Ephedra Herb are considered to be due to ephedrine alkaloids. We have found that Ephedra Herb has ephedrine alkaloids-independent pharmacological actions and utilized cation-exchange column chromatography to eliminate ephedrine alkaloids from Ephedra Herb extract (EHE), resulting in ephedrine alkaloids-free Ephedra Herb extract (EFE). EFE had an analgesic effect similar to that of EHE. Moreover, EHE and EFE contain both herbacetin-glycosides and Ephedra Herb Macromolecule Condensed-Tannin (EMCT) associated with analgesic effect. Therefore, EFE is a potentially safe and useful analgesic drug.