Helenin

Helenin
	Alantolactone
	Isoalantolactone
Names
	IUPAC names Alantolactone: (3aR,5S,8aR,9aR)-5,8a-Dimethyl-3-methylene-3a,5,6,7,8,8a,9,9a-octahydronaphtho[2,3-b]furan-2(3H)-one; Isoalantolactone: (3aR,4aS,8aR,9aR)-8a-Methyl-3,5-bis(methylene)decahydronaphtho[2,3-b]furan-2(3H)-one
	Other names Elecampane camphor, Inula camphor, Alant camphor
Identifiers
CAS Number	Alantolactone: 546-43-0 ; isolantolactone: 470-17-7 ;
3D model (JSmol)	Alantolactone: Interactive image; isolantolactone: Interactive image;
ChEBI	Alantolactone: CHEBI:2540; isolantolactone: CHEBI:5981;
ChEMBL	Alantolactone: ChEMBL136356; isolantolactone: ChEMBL137803;
ChemSpider	Alantolactone: 65564; isolantolactone: 66028;
EC Number	Alantolactone: 208-899-3;
KEGG	Alantolactone: C09289; isolantolactone: C09484;
PubChem CID	Alantolactone: 72724; isolantolactone: 73285;
UNII	Alantolactone: M7GSN5Q1M6 ; isolantolactone: BYH07P620U ;
	InChI InChI=1S/C15H20O2/c1-9-5-4-6-15(3)8-13-11(7-12(9)15)10(2)14(16)17-13/h7,9,11,13H,2,4-6,8H2,1,3H3/t9-,11+,13+,15+/m0/s1 Key: PXOYOCNNSUAQNS-AGNJHWRGSA-N; isolantolactone: InChI=1S/C15H20O2/c1-9-5-4-6-15(3)8-13-11(7-12(9)15)10(2)14(16)17-13/h11-13H,1-2,4-8H2,3H3/t11-,12+,13-,15-/m1/s1 Key: CVUANYCQTOGILD-QVHKTLOISA-N;
	SMILES Alantolactone: C[C@H]1CCC[C@]2(C1=C[C@H]3[C@@H](C2)OC(=O)C3=C)C; isolantolactone: C[C@]12CCCC(=C)[C@@H]1C[C@H]3[C@@H](C2)OC(=O)C3=C;
Properties
Chemical formula	C15H20O2
Molar mass	232.323 g·mol−1
Appearance	Crystalline powder
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Helenin is a phytochemical mixture found in many plant species, including the Inula helenium (elecampane) of the family Asteraceae. It is a mixture of two isomeric sesquiterpene lactones, alantolactone and isoalantolactone.

In 1895 the German scientists Julius Bredt and Wilhelm Posh extracted helenin from Inula helenium and determined its physical and chemical properties.