β-Elemene in zedoary turmeric oil injection induces dyspnea by binding to hemoglobin and upregulating HIF-1α.

Ethnopharmacological Relevance: Zedoary turmeric oil injection (ZTOI) extracted from the rhizome extract of Curcuma phaeocaulis Valeton, Curcuma wenyujin Y. H. Chen et C. Ling or Curcuma kwangsiensis S. G. Lee et C. F. Liang, is widely used for the treatment of virus-induced upper respiratory tract infections, peptic ulcers, viral pneumonia, etc. However, it has attracted widespread attention because it often causes adverse drug reactions (ADRs), including dyspnea. However, little is known about the mechanism underlying dyspnea caused by ZTOI, which limits its clinical application.

Aim Of The Study: To investigate the major pathophysiologic signatures and underlying mechanism of ZTOI-related dyspnea.

Methods: Respiratory function detection was used to explore the pathophysiologic signature of dyspnea induced by ZTOI. UV-vis absorption spectroscopy and isothermal titration calorimetry were applied to test the interaction between ZTOI and hemoglobin (Hb). GC‒MS was used to identify the main components in ZTOI. Molecular docking, surface plasmon resonance, and circular dichroism spectroscopy were employed to test the reaction between β-elemene and Hb. Western blot was performed to investigate the effect of β-elemene on the hypoxia signaling pathway.

Results: The results showed that ZTOI-induced dyspnea was related to a decreased oxygen carrying capacity of Hb. The molecular interaction between ZTOI and Hb was proven. Notably, β-elemene in ZTOI exhibited high binding affinity to Hb and altered its secondary structure. Furthermore, it was found that β-elemene downregulated the expression of prolyl hydroxylase-domain protein 2 and upregulated the expression of hypoxia-inducible factor-1α.

Conclusions: Our study is valuable for better understanding the pathophysiological characteristics and underlying mechanism of ZTOI to ensure its safe clinical application. We also provided a strategy to elucidate the underlying mechanism based on inspiration from clinical ADR phenotypes for investigating other medical products with ADRs in the clinic.