A New Labdane Diterpene from the Flowers of @@iSolidago canadensis@

A new labdane diterpene, 9^a,16^y-dihydroxy-6-oxo-7,13-labdadien-15,16-olide (solicanolide, 1) and six known compounds identified as quercetin (2), 3-@iO-caffeoylquinic acid (3, neochlorogenic acid), 5-@iO-caffeoylquinic acid (4, chlorogenic acid), 4,5-di-@iO-caffeoylquinic acid (5), 3,5-di-@iO-caffeoylquinic acid (6) and 3,4-di-@iO-caffeoylquinic acid (7) were isolated from the flowers of @@iSolidago canadensis.@ To our knowledge, compound 7 was isolated for the first time in @@iS. canadensis.@ This work describes the isolation of compounds 1--7 and the structure elucidation of a new compound identified as compound 1. Solicanolide (1) showed cytotoxic activity against A549 (IC@@d50@: 13^c2 ^kM), DLD-1 (IC@@d50@: 26^c2 ^kM) and WS1 (IC@@d50@: 17^c1 ^kM) cell lines.