Effect of combination of gastrodia and uncaria on pharmacokinetics of gastrodin and rhynchophylline / 中国中药杂志

ABSTRACT

To investigate the effect of the combination of gastrodia and uncaria on the pharmacokinetics of gastrodin and rhynchophylline, and determine their pharmacokinetic parameters after administration of the combination of gastrodia and uncaria at the ratio of 12∶9. Compared with uncaria group or gastrodia group, Cmax and AUC of both gastrodin and rhynchophylline were significantly increased, and tmax was retroceded by 1.5 h for rhynchophylline and 0.25 h for gastrodin. The change of tmax resulted in a 1.25 h difference in the peak time between gastrodin and rhynchophylline , which was the same between them. Uncaria shows a more effect in suppressing hyperactive Yang, while gastrodia has a balancing effect by nourishing Yin and suppressing hyperactive Yang. As a result, gastrodia could exert the effect in nourishing Yin and suppressing effect of uncaria, which could avoid the deficiency of Yang affecting Yin due to mono-treatment of uncaria. On one hand, the enhanced AUC and Cmax of gastrodin could increase the average plasma drug concentration of gastrodin, and remedy the losing effect of uncaria at the early stage; On the other hand, the increased AUC and Cmax of rhynchophylline could make up the quick elimination of gastrodia in vivo at the late stage. Their combination could lead to an increased anti-hypertensive effect with the balance of Yin and Yang. They showed unique advantages compared with simple dosage increase of western medicines. The results were consistent with the principle of TCM treatment for the hypertension due to hyperactivity of the liver Yang. In short, this study gives a good pharmacokinetic explanation of the balance of Yin and Yang and TCM treatment for both symptoms and root cause.