Ephedrae herba: A comprehensive review of its traditional uses, phytochemistry, pharmacology, and toxicology.

Abstract

Ephedrae herba (called Mahuang in China) is the dried herbaceous stem of Ephedra sinica Stapf, Ephedra intermedia Schrenk et C. A. Mey., and Ephedra equisetina Bge. Ephedrae herba has a long history of use as an herb, and it was originally recorded in Sheng Nong's herbal classic. Ephedrae herba has also been widely used as both medicine and food. In the clinic, Ephedrae herba is commonly used for treating colds, bronchial asthma, nasal congestion, and other diseases. This review aims to provide a systematic summary on the traditional use, chemical constituents, pharmacological effects, clinical applications, quality control, toxicology, and pharmacokinetics of Ephedrae herba to provide a theoretical basis for further reasonable development of Ephedrae herba in clinical practice and creation of new drugs. Information on Ephedrae herba was gathered from various sources, including the scientific databases including CNKI, PubMed, SciFinder and ScienceDirect, classical books on traditional Chinese herbal medicine, Ph.D. and M.Sc. dissertations; Baidu Scholar; and from different professional websites. Ephedrae herba is distributed in regions of China and other areas. Ephedra and its compound preparations can be used for colds, bronchial asthma, nasal congestion and other diseases. Approximately 281 chemical constituents have been isolated from Ephedrae herba, including alkaloids, flavonoids, tannins, polysaccharides, volatile oils, organic acids, and other compounds. Among these constituents, alkaloids and volatile oils are the most abundant and represent the major bioactive constituents. Ephedrae herba possesses multiple pharmacological activities, including diuretic effect, anti-allergic effect, blood pressure regulatory, anti-inflammatory effect, anti-oxidation effect and anti-viral effects. Ephedrine hydrochloride and pseudoephedrine hydrochloride are generally selected as indicators for the quantitative determination of Ephedrae herba. The maximum dosage of Ephedrae herba should not exceed 10 grams. If overused, adverse reactions such as palpitations, sweating, irritability and insomnia will occur. Ephedrae herba is an ancient herbal medicine with a broad spectrum of pharmacological activities that has been used for thousands of years in China. It is one of the most commonly used herbal components of the TCM formulas. Hydrochloride and pseudoephedrine are the major bioactive constituents. However, there is a need to further understand the mechanisms of active components of Ephedrae herba. Future studies should perform an in-depth analyses of the pharmacokinetics and mechanisms of toxicity of Ephedrae herba. Quality standards should be developed to correspond to the various application methods to ensure the efficacy of drugs in actual treatment.