Pharmacokinetic Interaction between Asari Radix et Rhizoma and Dried Ginger (Zingiber officinalis) in Rats

Introduction:: Asari Radix et Rhizoma (ARR) and dried ginger (Zingiber officinalis) (DG) are often used together in drug preparations in traditional Chinese medicine (TCM) to treat respiratory diseases including cold, bronchitis and pneumonia. Previous studies suggested that ARR and/or DG may influence the pharmacokinetics of other herbal components. In the current study, we examined pharmacokinetic interactions between ARR and DG in rats after oral administration. Methods:: We developed a method based on ultra-high-performance liquid chromatography-tandem mass spectrometry to simultaneously measure serum concentrations of two active components each in ARR (L-asarinin and sesamin) and DG (6-gingerol and 6-shogaol). Adult Sprague-Dawley rats were starved overnight, then given ARR extract, DO extract, or a co-decoction of ARR and DG by gastric gavage (6 g raw material per kg body weight; n = 6 per group). Blood samples were collected prior to drug administration and at the following times (h) afterward: 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0, 12.0 and 24.0. Pharmacokinetic parameters were compared using Student’s t test for independent samples. Results:: A simple, rapid, sensitive analytical method has been developed to detect four bioactive components simultaneously in the ARR-DG herbal pair. Pharmacokinetic parameters including Cmax, Tmax, T1/2 and AUC(0~t) were calculated using the non-compartmental model with the DAS 2.0 pharmacokinetic software. For L-asarinin, Tmax was 2.00 ± 0.00 h in ARR animals and 1.67±0.26 h in ARR-DG animals (P<0.05), T1/2 was 8.58 ± 1.75 h in ARR and 11.93 ± 2.13 h in ARR-DG (P<0.05). For 6-gingerol, Cmax was 350.48 ± 23.85 ng/mL in DG animals and 300.21 ± 20.02 ng/mL in ARR-DG (P<0.01), Tmax was 2.83 ± 0.41 h in DG and 2.17 ± 0.41 h in ARR-DG (P<0.05) and AUC(0~t) was 1.93 ± 0.15 mg/mL•h in ARR and 1.70 ± 0.15 mg/mL•h in ARR-DG (P<0.05). For 6-shogaol, Cmax was 390.28 ± 26.02 ng/mL in DG animals and 455.63 ± 31.01 ng/mL in ARR-DG (P<0.01), Tmax was 2.93 ± 0.10 h in DG and 1.92 ± 0.10 h in ARR-DG (P<0.01), T1/2 was 3.74 ± 0.29 h in DG and 3.28 ± 0.22 h in ARR-DG (P<0.01), and AUC(0~t) was 2.15 ± 0.18 mg/mL•h in DG and 2.73 ± 0.15 mg/mL•h in ARR-DG (P<0.01). Conclusions:: Pharmacokinetic interations between ARR and DG decrease Tmax, increase T1/2 but do not affect overall bioavailability of L-asarinin in ARR. The interactions in ARR-DG decrease Cmax and Tmax but increase T1/2 and AUC(0~t) of 6-gingerol in DG. The interactions increase Cmax and AUC(0~t) but decrease Tmax and T1/2 of 6- shogaol in DG. Interactions in ARR-DG do not affect the pharmacokinetics of sesamin.