ABSTRACT
Objective: Astragalus Radix (AR, Huangqi in Chinese) has been widely used as a qi (energy) restoring herb that is thought to act through reinvigorating the spleen and lung. Aconite is used to rebalance the body temperature during illness and played an irreplaceable role in disease control since ancient times, but it is limited by its strong neuro and cardiotoxicity. Since the Song Dynasty (1227), the two herbs have been commonly used as herbal pairs including in the famous Qifu Decotion, from the “Wei's Family Prescription”. However, many ancient texts also record that they are not compatible using together, suggesting they can have negative outcomes when mixed. This study investigated whether Astragali Radix had either positive or negative effects on absorption of six different active alkaloids derived from aconite. Methods: Single intestinal perfusion model was used to study the effects of Astragali Radix on aconite alkaloids absorption. Response of ABC transporters and distribution of three tight junction proteins on the surface of intestinal enothelium were assessed by Reverse Transcription-Polymerase Chain Reaction (RT-PCR), Western blot and immunofluorescence microscopy, respectively. Results: The results showed that aconite alkaloids absorption could be inhibited, and different concentrations of Astragali Radix considerably increased the expression levels of the ABC transporters and tight junction proteins with Astragali Radix treatment. Conclusion: These results suggest that Astragali Radix can block absorption of aconite alkaloids through the upregulation expression of ATP-binding cassette transporters (ABC transporters) and tight junction proteins. It demonstrates that co-administration of Astragali Radix with other drugs might change the absorption profile of the second drug which is important to know in clinic therapy.
ABSTRACT
Objective To study the effect of Radix Astragali and Aconiti Lateralis Radix Preparata on the intestinal absorption of the three kinds of monoester-type alkaloids (benzoylthioate, benzoyl neostearine, and benzoyl aconitine) and three kinds of diester-type alkaloids (hypaconitine, neaconitine, and aconitine) in Aconiti Lateralis Radix Preparata. Methods The rat duodenum, the jejunum, and the ileum were selected to study the intestinal segment. The apparent permeability coefficient (Papp) was used to evaluate the effect of Radix Astragali on the Papp of six kinds of alkaloids in Aconiti Lateralis Radix Preparata. Results When Aconiti Lateralis Radix Preparata and Radix Astragali was 3:1, Radix Astragali can significantly reduce the dipeptide alkaloid Papp in the duodenum and ileum and reduce the monoester-type alkaloid Papp in three kinds of intestinal segments; When Aconiti Lateralis Radix Preparata and Radix Astragali was 1:1, except in the ileum, Radix Astragali can significantly reduce the Papp of the diester-type alkaloid; When Aconiti Lateralis Radix Preparata and Radix Astragali was 1:3, Radix Astragali can significantly reduce the Papp of the monoester-type alkaloid (except the parenteral) and significantly reduced the Papp of the three diester-type alkaloids. Conclusion Radix Astragali can inhibit the absorption of aconite alkaloids, and its inhibition effect is different due to different compatibility ratios, types of alkaloids and intestinal segments.