Comparison of the Immunomodulatory Effect of TCM Formulas Containing Either Astragali Radix or With This Replaced by Hedysari Radix

Hedysari Radix (Hong Qi) is a commonly substituted material with similar functions to Astragali Radix (Huang Qi). However, it is still misused as Huang Qi, even though people know they are different species. This study aims to find evidence that Hong Qi can replace Huang Qi in traditional Chinese medicine (TCM) formulas used for immunomodulation. Therefore, we evaluated the immunomodulatory effects of both medicines on dendritic cells. The water extract of Hong Qi showed a more substantial immunomodulatory effect on dendritic cells in 500 μg/mL concentration compared to Huang Qi in the same dosage. Furthermore, we selected the 23 TCM formulas to investigate their immunomodulatory function when Huang Qi and Hong Qi alternated within a formula. Among them, 6 formulas containing Hong Qi demonstrated a better immunomodulatory effect on the dendritic cells than those containing Huang Qi. The other formulas containing Hong Qi showed an insignificantly different physiological impact from the original formulation. Therefore, based on the TCM theory and our experimental results, replacing Huang Qi with Hong Qi for a formula could be more suitable when the immunomodulatory effect or nourishing Qi is required.