New Sesquiterpene Lactones and Other Constituents from Helianthus petiolaris

Abstract

Three new sesquiterpene lactones, 11alpha,13-dihydroxydehidrocostuslactone (1), the unusual 5, 10-epoxygermacranolide 4,15-anhydrohelivypolide (2), and 3-methoxy-1,2-anhydridoniveusin A (4), together with the 5,10-epoxygermacranolide helivypolide, four known 3,10-furanoheliangolides, and five known kaurane- and trachylobane-type diterpenes, have been isolated from Helianthus petiolaris.

Sesquiterpene Lactones as Allelochemicals

“…The NMR data of 4 were identical to those published for 4,15-anhydrohelivypolide ( 15 ) . This suggests that structure 15 must be revised to 4 .…”

“…Those authors suggested that this compound could be an artifact of helivypolide B. The structure assigned for helivypolide B was 16 . Comparison of spectra of helivypolide B and 4 suggest that the structure of 16 should be revised to 17 .…”

“…The NMR data of 4 were identical to those published for 4,15anhydrohelivypolide (15). 12 This suggests that structure 15 must be revised to 4. Those authors suggested that this compound could be an artifact of helivypolide B.…”

“…The structure assigned for helivypolide B was 16. 12 Comparison of spectra of helivypolide B and 4 suggest that the structure of 16 should be revised to 17. This is further supported by the absence of coupling between the signal at δ 6.33, which should be assigned to H-3 in structure 16, and H-4 at δ 3.09.…”

Natural sesquiterpenoids

“…234 The structures of 8-deacetoxy-11b,13-dihydroperoxyferolide, 235 1,10-epoxyparthenolide, 1,10-epoxy11b,13-dihydroparthenolide, 11b,13dihydrocostunolide, 236 8b-angeloyloxy-9a-acetoxycalyculatolide and 11,13-dihydro-11a,13-epoxyatripliciolide-8bangelate 237 have been determined by X-ray analysis. Known germacranolides have been obtained from Artemisia fragrans, 238 Centaurea cineraria, Centaurea conifera, 239 Centaurea derventana, Centaurea kosaninii, 240 Helianthus laetiflorus, 241 Neurolaena lobata 242 and Schkuhria multiflora. 243 The antiinflammatory activity of three germacrane lactones, which have been isolated from Tithonia diversifolia, has been examined.…”