Ephedra Species

Botanically, Ephedra () is a member of the smallest and most problematic division of flowering plants, the Gnetopsida, and major questions remain unanswered about the taxonomy of the Gnetopsida and the evolutionary relationships of the different genera within the division. Ephedra is the largest and most widely distributed genus in the Gnetopsida, a subgroup of the gymnosperms. Many anatomical and reproductive characters of Ephedra are angiosperm-like. Recent molecular and chemical studies support the view that the Gnetopsida are the closest living relatives of the angiosperms but that the angiosperms are not derived from them. Pharmacologically, Ephedra has been the main botanical source of the active alkaloids l-ephedrine (E) and d-pseudoephedrine (PE) for thousands of years, with records of its medicinal use dating to 5000 years b.p.. The alkaloids E and PE remain important drugs today – the current world consumption of d-pseudoephedrine salts (PE-sulphate and PE-hydrochloride) stands at 1000-2000 tonnes per annum with a value of approximately $100-200 million. Powdered Ephedra stems are used in traditional herbal medicines as a hypertensive aid to treat asthma, nose and lung congestion, hay fever, and several Read more […]

Asteraceae: Drug Interactions, Contraindications, And Precautions

Patient survey data from Canada, the U.S., and Australia show that one in five patients use prescription drugs concurrently with CAM. The inherent polypharmaceutical nature of complementary and alternative medicine increases the risk of adverse events if these complementary and alternative medicine either have pharmacological activity or interfere with drug metabolism. Since confirmed interactions are sporadic and based largely on case reports, advice to avoid certain drug-CAM combinations is based on known pharmacological and in vitro properties. Known Hypersensitivity to Asteraceae Cross-reactive sesquiterpene lactones are present in many, if not all, Asteraceae. Patients with known CAD from one plant may develop similar type IV reactions following contact with others. Affected patients are often advised to avoid contact with all Asteraceae, yet this advice is based on limited knowledge of cross-reactivity between relatively few members of this large family. Some authorities recommend avoiding Asteraceae-derived complementary and alternative medicine if, for example, the patient is known to have IgE-mediated inhalant allergy to ragweed. While a reasonable approach, this ignores a number of important facts: (1) Read more […]