Abstract
Current interest in Ma Huang, 1 the Chinese drug plant Ephedra, makes imperative a study of the various species of the genus, especially with respect to the activity and nature of the chemical principles which they yield.
The problem is complicated by the lack of knowledge concerning the effect of species variation and ecological conditions upon the yield of physiologically active substances.
A complete study involves: (1) Determination of the species and varieties which contain physiologically active substances. (2) The isolation and identification of the active principles. (3) The experimental and clinical testing of the pure principles obtained.
In the work reported in this paper our efforts have been confined to a comparative study of the activity of Ephedra californica Wats and Ephedra nevadensis Wats, using for comparison Ephedra obtained from Chinese drug shops in San Francisco. We have also used an ephedrine sulphate solution prepared by Eli Lilly Company, and a sample of the pure hydrochloride obtained from the Peking Union Medical College.∗
Ten per cent infusions of the crude drug have been prepared in a number of ways : water, 0.9 per cent NaCl, 50 per cent ethyl alcohol, 50 per cent ethyl alcohol containing 1 per cent tartaric acid, and water slightly acidified with H2SO4. In all cases the solutions were heated on a steam bath 3 to 4 hours. Prior to use, the alcohol extracts were evaporated and original volume restored with 0.9 per cent NaCl. These solutions, kept in tightly stoppered pyrex flasks, retained their original activity up to 19 days, when the experimental work reported here was concluded.
Blood pressure experiments with a number of rabbits indicate that certain specimens of Ephedra californica Wats contain a small amount of pressor material.
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