Phytochemical profiles of the leaves of Stizolophus balsamita and Psephellus sibiricus and their chemotaxonomic implications.

Seven germacranolides - balsamin, izospiciformin, stizolin, 9α-hydroxyparthenolide, 8α-E-(4'-hydroxy)-senecioyloxy-9α-hydroxyparthenolide, stizolicin and 11βH,13-dihydrostizolicin, as well as one undescribed phenol glycoside 3-(3,4-dihydroxyphenyl) propyl senecioate 3-O-β-glucopyranoside were isolated from the leaves of Stizolophus balsamita growing in Iran. Three coumarins, scoparone, scopoletin, umbelliferone and two guaianolides, cynaropicrin and desacylcynaropicrin 8α-(Z)-(4'-hydroxy-2'-methyl)butenoate (= cebellin F) were isolated from the leaves of Psephellus sibiricus. Phytochemical profile of Stizolophus balsamita growing in Iran differs from that of Stizolophus balsamita growing in Kazakhstan. Therefore, the taxonomic separation of Stizolophus balsamita from Iran is suggested. The results also suggest that isolated coumarins may be a chemotaxonomic marker of the Psephellus species. Moreover, the presence of germacranolides in Centaureinae species with stout apical spine ended bracts of flower (S. balsamita) and guaianolides in other species with appendages of the bracts without apical spine (P. sibiricus) suggests a possible connection between the chemical structure of the sesquiterpene lactones and morphology of flowers in the species of the Centaureinae subtribe. In addition, we propose a new 1 H NMR approach for the detection of hydroxyl groups in sesquiterpene lactones.