riligustilide riligustilide riligustilide is a nonsteroidal phytoprogestogen that is found in ligusticum chuanxiong. it is a very weak agonist of the progesterone receptor (ec50 ≈ 81 μm). another compound in the plant, 3,8-dihydrodiligustilide, is also a phytoprogestogen, but is almost 1,000-fold more potent in comparison (ec50 = 90 nm). riligustilide names iupac name (3s,3′z,5′ar,6′s,7′as)-3′-butylidene-6′-propylspirobenzofuran]-1,1′-dione identifiers cas number 89354-45-0 3d model (jsmol) interactive image chemspider 4946720 pubchem cid 6442656 unii 6gb38t262b y inchi inchi=1s/c24h28o4/c1-3-5-11-19-16-13-12-14-17(8-4-2)24(21(14)20(16)23(26)27-19)18-10-7-6-9-15(18)22(25)28-24/h6,9,11,14,17,21h,3-5,7-8,10,12-13h2,1-2h3/b19-11-/t14-,17+,21+,24-/m1/s1key: tysomzqrygbskn-drqjqjqisa-n smiles ccc/c=c\1/c2=c(3(cc2)(34c5=c(c=ccc5)c(=o)o4)ccc)c(=o)o1 properties chemical formula c24h28o4 molar mass 380.484 g·mol−1 except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). infobox references