Which plant genus is a natural source of ephedrine alkaloids used as decongestants? Ephedra is the genus that naturally produces ephedrine and related alkaloids.
Ephedra is a genus of gymnosperm shrubs adapted to dry, sunny habitats across parts of Asia, Europe, Africa and the Americas. In traditional Chinese medicine, species such as Ephedra sinica are known as mahuang. Their stems contain ephedrine and pseudoephedrine, sympathomimetic compounds that can relieve nasal congestion by constricting blood vessels in swollen nasal tissue.
The genus has a long medical history. Chinese use of mahuang is documented from the Han dynasty, dated 206 BC–220 AD, while Japanese chemist Nagai Nagayoshi isolated and characterized ephedrine in the late nineteenth century. Modern pharmaceutical ephedrine is now often manufactured synthetically rather than extracted from plants.
The common confusion is between Ephedra, the plant genus, and ephedrine, the chemical drug. Artemisia, Valeriana and Gentiana are medicinal genera, but they are not the canonical botanical source named in this question. Ephedra supplements also carry significant cardiovascular risks and are regulated in many places.