Effect of Jiegeng () on Jingjie () "" into the lungs based on pharmacokinetics.

Objective: To investigate whether Jiegeng (Radix Platycodi, RP) has a Yin-Jing potentiating effect on Jingjie (Herba Schizonepetae Tenuifoliae,ST). We investigated the pharmacokinetics and tissue distribution of pulegone, the active ingredient in ST volatile oil, in rats to verify the scientific validity of the Yin-Jing doctrine, the basic theory of Traditional Chinese Medicine (TCM).

Methods: The volatile oil and aqueous extract of ST were extracted by hydrodistillation. RP's aqueous extract underwent aqueous extraction. After individual and co-administration, we conducted pharmacokinetic and tissue distribution studies on Sprague-Dawley male rats.

Results: Peak concentration (Cmax), mean retention time from 0 to ∞ (MRT0→∞), and area under the curve (AUC0→10), (AUC0→∞) were 1.51, 1.14, 2.34, and 3.86 times higher in the co-administration group than in the individual administration group, respectively (P < 0.05). In addition, half-life (T1/2) was significantly prolonged in the co-administration group (P < 0.05). Meanwhile, the clearance and elimination rate constant (Ke) in the co-administration group were significantly lower than those in the individual administration group, just 50% of those in the individual administration group (P < 0.05). After co-administration of the drug, the pulegone content in all tissues of the rats was elevated to varying degrees, especially a significant increase in the drug content in lung tissues (P < 0.05).

Conclusion: After co-administration, the retention of pulegone in the body was prolonged, the elimination of pulegone from the body was delayed, and the accumulation of pulegone in the lungs was facilitated. Therefore, using RP as a Yin-Jing drug concoction has a significant cumulative effect of inducing upward mobilization and targeting lung tissues.