PHARMACOLOGICAL STUDIES ON CHINESE RAUWOLFIA,Ⅰ.THE HYPOTENSIVE EFFECT OF RAUWOLFIA LEAVES COLLECTED FROM KWANGTUNG AND ITS ALKALOID

The Chinese rauwolfia has been identified as Rauwolfia verticillata (Lour.) Baill. A crude extract, and the alkaloid of rauwolfia leaves collected from Kwangtung have been found to decrease the blood pressure of anesthetized normal and unanesthetized hypertensive animals. Intravenous injection of the crude extract to anesthetized dogs at a dose of 100—150 mg (leaves) /kg decreased the blood pressure to the extent of 60—120 mm. Hg. The alkaloid at 1 mg/kg caused a decrease of 50—100 mm. Hg; at the same time the respiration became slightly slower, the intestinal motility increased, and the carotid pressor reflex decreased slightly. The hypotensive effect lasted for 1—3 hrs. When administered orally to two "spontaneous" hypertensive dogs and one dog with renal hypertension, the crude extract at a daily dose of 1—2 g (leaves)/kg in a course of 10 days caused a drop of about 50 mm. Hg of the blood pressure of all dogs. Two renal hypertensive dogs receiving the alkaloid orally at 5 and 10 mg/kg/day for up to 20 days showed no change in blood pressure, while all the renal hypertensive rats receiving 20, 40 or 80 mg/kg/day by the same route for 10 days showed remarkable decreases.