[Mahuang (herbaceous stem of Ephedra spp.): chemistry, pharmacodynamics, and pharmacokinetics]

The Chinese medicinal herb Mahuang is herbaceous stem of Ephedra sinica, E. intermedia, or E. equisetina(Family, Ephedraceae). In China, Mahuang has been used, all the way over a millennium, as a key component herb of many herbal medicines for management of epidemics of acute respiratory illness and is also used in officially recommended herbal medicines for COVID-19. Mahuang is the first-line medicinal herb for cold and wheezing and also an effective diuretic herb for edema. However, Mahuang can also exert significant adverse effects. The key to safety and effectiveness is rational and precise use of the herb. In this review article, we comprehensively summarize chemical composition of Mahuang and associated differences in pharmacognosy, pharmacodynamics and pharmacokinetics of Mahuang compounds, along with the adverse effects of Mahuang compounds and products. Based on full understanding of how Mahuang is used in Chinese traditional medicine, systematic research on Mahuang in line with contemporary standards of pharmaceutical sciences will facilitate promoting Chinese herbal medicines to become more efficient in management of epidemic illnesses, such as COVID-19. To this end, we recommend research on Mahuang of two aspects, i.e., pharmacological investigation for its multicompound-involved therapeutic effects and toxicological investigation for clinical manifestation of the adverse effects, chemicals responsible for the adverse effects, and conditions for safe use of the herb and the herb-containing medicines.