Pharmacological effects of butylidenephthalide

The pharmacological effects of synthetic butylidenephthalide (Bdph), the most potent antispasmodic agent found in the neutral oil of Ligusticum wallichii Franch., were examined in this study. In vivo, Bdph exerted a significant antihypertensive effect in anaesthetized renal hypertensive rats at a dose of 30 mg/kg (i.v. or i.p.), or 60 mg/kg (p.o.). Bdph antagonized noradrenaline (NA) induced increases in blood pressure in anaesthetized normotensive rats. In addition, Bdph prevented the pituitrin-induced T-wave lowering of the ECG in anaesthetized rats. It also dose-dependently decreased coronary arterial pressure in dogs. It is concluded that Bdph dilates coronary vessels. In vitro, Bdph non-competitively antagonized adrenaline-induced contraction in isolated rabbit aortic strips. It also significantly antagonized the NA-induced maximum decrease in perfusion rate of isolated rabbit ears. However, the vasodilator effect may cause a heat loss because Bdph significantly lowered the rectal temperature of rats at ambient temperature of 20°C, but not at 30°C. Bdph might be a useful coronary dilator and antihypertensive drug.