A eudesmanolide from Picris spinifera

Phytochemical Characterization of Phitosia crocifolia, a Monotypic Representative of Greek Flora

“…Compound 9 was identified as tanapraetenolide 9 , while compounds 10 and 11 presented similar structures with a methyl group on position 13 instead of methylene and a β -oriented hydroxyl group on position 1. Compound 10 was identified as the 2-oxo-11,13 α -dihydrosantamarin ( 10 ) and has been previously reported from Picris spinifera France 11 , while compound 11 proved to be its isomer in position 13, thus it was named 2-oxo-11,13 β -dihydrosantamarin ( 11 ). More specifically, 11 differs only on the orientation of CH 3 -13 and contrary to 10 bears β CH 3 , as a result, the corresponding methyl signal appears downshifted at δ H 1.24; the different stereochemistry affects also the chemical shifts of H-6 ( δ H 4.22.…”

“…The assignment of relative configuration was further accomplished by NOESY spectrum verifying the proximities of H 3 -13 β with H-6 and Η 3 -14. In Table 3 , the 1 H-NMR data are provided for compound 10 to complete the data presented by Kijjoa et al 11 .…”

“…The non-polar extract (A) of the aerial parts of P. crocifolia was fractionated into ten fractions by VLC followed by HPLC to result in 16 isolated compounds. Seven known isolates, namely 2β-hydroxysantamarine-1β-D-glucopyranoside (4) [8], glandulosine C (8) [9], tanapraetenolide (9) [10], 2-oxo-11α-,13β-dihydrosantamarin (10) [11], loliolide (14) [12,13], p-hydroxybenzoic acid (15) [14], p-hydroxyphenylacetic acid (16) [15], and nine previously undescribed compounds 1-3, 5-7 and 11-13 were identified. The polar extract (B) of the aerial parts was similarly fractionated by VLC followed by repeated CC and RP 18 -HPLC and yielded six compounds.…”