A new study published in Engineering reveals that obakulactone (OL), a natural tetracyclic triterpenoid isolated from Phellodendri cortex, exerts a therapeutic effect on rheumatoid arthritis (RA) by promoting the degradation of acyl coenzyme A thioesterase 1 (ACOT1) via the ubiquitin‒proteasome pathway and restoring the homeostasis of unsaturated fatty acids.