Blocking Effect of Chaga Mushroom (Inonotus oliquus) Extract for Immune Checkpoint CTLA-4/CD80 Interaction

Abstract

Inonotus obliquus, also known as the Chaga mushroom, has been used as a traditional medicine to treat many different diseases in Asia. Ethanol and water extraction were performed to examine the blocking effect of the Chaga mushroom on the CTLA-4/CD80 interaction. The inhibitory activities of the Chaga mushroom/70% EtOH extract (CME) and the Chaga mushroom/water extract (CMW) were confirmed using several cell-based assays. To identify the contents of major compounds CME and CMW, we performed HPLC analysis. The content of lanosterol (1) in CME was 0.41%. Our findings provide experimental evidence that the Chaga mushroom can develop a small-molecule inhibitor that blocks the CTLA-4/CD80 interaction.