Research of Chinese Drug Mahuang on its Resources and Quality Evaluation

For resource surveys and evaluation quality, we went to the main habitats of Mahuang (Ephedrae Herba) including all of their main areas of production, such as, the provinces of Inner Mongolia, Shanxi, Ningxia, Gansu, Qinhai, Xinjiang, Liaoning in China. We found that Ephedra equisetina is becoming extinct. These places were reported to have an adequate supply of E. equisetina, but nothing was found in the year 2005–2006. The same situation was observed for E. intermedia. The amount of E. intermedia has been seriously diminished.

Three Chinese official sources of Ephedra herb (herbaceous stems), 64 samples (34 batches of Ephedra sinica, 23 batches of E. intermedia and 7 batches of E. equisetina) were collected from those habitats, and were investigated for quality control.

The results show:

(I) The contents of five main alkaloids, ephedrine (E), pseudoephedrine (PE) etc., were variable among the 3 plants of Ephedra. The content of E and PE in E. sinica differed from E. intermedia. HPLC fingerprint of E. sinica also was different from E. intermedia.

(II) Relaxation effect of total alkaloid of E. sinica was 1.5 times stronger than E. intermedia. The cough relieving effect of the water extract of E. sinica and E. equisetina was 2 to 3 times stronger than E. intermedia. Among aqueous extract of 3 herbs of Ephedra, acute toxicity of E. equisetina was the greatest, the next was E. sinica, and E. intermedia was the weakest. The differences in chemical or pharmacological aspects among the three plants were not significant enough to warrant saying that the three Ephedra species should be treated as different drugs

(III) Alkaloids mainly distributed in pith and scarcely distributed in other parts in the stem of the plant, E. sinica or E. intermedia, and alkaloid contents in the upper portion were 1.0 to 2.3 times as high as the lower portion of the stem. This difference related to histological structures in the upper and lower portions of the stem, i.e. proportion of lignified tissues and pith. Therefore, it may be suggested that if ephedrine manufactures collect only the upper segments of stems of Mahuang they could produce more alkaloids in future process of the manufactures. On the other hand, based on our earlier research, cutting only the upper segments off and not the whole stem can prevent the Ephedra resources from being seriously damaged. The result also suggests that proper care should be taken in the preservation, transport and sale of the plant (the drug Ephedrae Herba), because we noticed that the upper segments of a stem usually fall off from the plant and are lost during drying process etc., which will obviously impact the quality of the drug.