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'-methylbut-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-nordehydrocalohastine ( 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.