Germacrane-type sesquiterpenoids with cytotoxic activity from Sigesbeckia orientalis

Sesquiterpene Lactones from Sigesbeckia glabrescens Possessing Potent Anti-inflammatory Activity by Directly Binding to IKKα/β

“…Compound 7 , a colorless oil, exhibited a molecular formula of C 22 H 26 O 8 as deduced from its HRESIMS ion peak at m / z 463.1629 [M + HCOO] − (calcd for C 23 H 27 O 10 , 463.1604). Analysis of the aforementioned spectroscopic data showed 7 to be similar to 16 (lecocarpinolide B) . The carbon signals at δ C 168.2 (C-1′), 129.2 (C-2′), 140.2 (C-3′), 14.5 (C-4′), and 12.2 (C-5′) were indicative of the presence of a tigloyoxy residue at C-8.…”

“…The other correlations in the HMBC spectrum are depicted in Figure . In addition, the relative configuration was assigned according to previous data and from a NOESY experiment. , The geometry for the Δ 1,10 double bond was assigned as E on the basis of a NOESY correlation of H-1/H-14. In turn, the NOESY correlations between H-4/H-6 and H-6/H-5a indicated that H-4, H-5a, and H-6 are all located at the same side of the ring.…”

“…Analysis of the NMR data for 4 revealed that it contains a tigloyloxy group [δ H 6.82 (1H, m, H-3′), 1.81 (3H, dd, J = 7.2, 1.2 Hz, H-4′), 1.79 (3H, t, J = 1.2 Hz, H-5′), as well as δ C 168.3 (C-1′), 129.3 (C-2′), 139.3 (C-3′), 14.4 (C-4′), 12.0 (C-5′)]. Compound 4 showed structural features similar to those of 13 ((4β,10 E )-6α,14,15-trihydroxy-8β-(tigloyloxy)­germacra-1­(10),11­(13)-diene-12-oic acid 12,6-lactone) . The main difference was that OH-14 and OH-15 in 4 were condensed to form a hemiacetal structure, which was deduced from the degree of unsaturation and the HMBC correlations from H-14 to C-1 and C-9.…”

“…The 14 known compounds ( 11 – 24 ) were identified by comparison with NMR data reported in the literature (Supporting Information). ,,− …”

Four New Acyclic Diterpenes From Siegesbeckia orientalis

“…Up to date, over 250 compounds have been identified and divided into three main groups, sesquiterpenoids (germacrane, guaiane, and cadinene types), diterpenoids (kaurane and pimarane types), and phenolics (flavone, flavanone, isoflavone, and chalcone). [4][5][6][7][8] The secondary metabolites from Siegebeckia species have been reported having antioxidative, antiallergic, fertility, anti-inflammatory, and cytotoxic activities. 6,9 S orientalis L is an annual herb.…”