Three new and two rare furanoeremophilanes from Senecio asirensis.

Three new furanoeremophilanes have been obtained from the aerial parts of Senecio asirensis (N. O. Asteraceae), and characterized as 6-hydroxylmethyl-9-methoxyl-4,11-dimethylnaphtho[2,3-b]furan, designated asirensane-a (1), 6-hydroxyl-1,2-dimethoxyl-4,6,11-trimethyl-6-hydronaphtho[2,3-a]furan-7-one, named asirensane-b (2), and (6,12-dihydroxyl-9-methoxyl-4-methyl-11-acetyl-3,4-dihydronaphtho[2,3-b]furan- 3-yl)methyl (2'Z)-2'-methyl-but-2'-enoate, designated asirensane-c (3). In addition, two rare furanoeremophilanes have also been isolated and characterized from this source, namely 9-methoxyl-4,11-dimethylnaphtho[2,3-b]furan, named 14-nordehydro-calohastine (4), and 4,11-dimethylnaphtho[2,3-b]furan-6,9-dione, designated as maturinone (5). Their structures have been elucidated on the basis of spectral analysis. The alcoholic extract was also tested for anti-inflammatory activity, which decreased edema by 22% at a dose of 500 mg kg-1 after 3 h with respect to the control group treated only with carrageenan, while the standard drug phenylbutazone showed a 50% decrease at a dose of 100 mg kg-1, indicating that the extract has moderate anti-inflammatory activity.