Pterosin B, a indanone found in bracken fern (Pteridium aquilinum), is an inhibitor of salt-inducible kinase 3 (Sik3) signaling. Pterosin B prevents chondrocyte hypertrophy and osteoarthritis in mice by inhibiting Sik3[1][2].
[1]. Hannah R.Dexter, et al. A concise stereoselective synthesis of pterosin B. Tetrahedron Letters, Volume 59, Issue 49, 5 December 2018, Pages 4323-4325. [2]. Yahara Y, et al. Pterosin B prevents chondrocyte hypertrophy and osteoarthritis in mice by inhibiting Sik3. Nat Commun. 2016 Mar 24;7:10959.