Further Sesquiterpene Lactones from Eupatorium altissimum

Antiprotozoal Sesquiterpene Lactones and Other Constituents from Tarchonanthus camphoratus and Schkuhria pinnata

In continuation of a search for new antiprotozoal agents from plants of the family Asteraceae, Tarchonanthus camphoratus and Schkuhria pinnata have been investigated. By following the promising in vitro activity of the dichloromethane extracts from their aerial parts, bioassay-guided chromatographic isolation yielded two known sesquiterpene lactones (1 and 2) from T. camphoratus and 20 known compounds of this type from S. pinnata. From the latter, a new eudesmanolide, (1R*,5S*,6R*,7R*,8R*,10R*)-1-hydroxy-8-[5″-hydroxy-4'-(2″-hydroxyisovaleroyloxy)tigloyloxy]-3-oxoeudesma-11(13)-en-6,12-olide (3), and two new germacranolides, 3β-(2″-hydroxyisovaleroyloxy)-8β-(3-furoyloxy)costunolide (14) and 1(10)-epoxy-3β-hydroxy-8β-[5'-hydroxy-4'-(2″-hydroxyisovaleroyloxy)tigloyloxy]costunolide (16), were obtained. Additionally, the flavonoid pectolinarigenin (24) and 3-hydroxy-4,5-dimethoxybenzenepropanol (25) were also isolated from S. pinnata. The compounds were characterized by analysis of 1D and 2D NMR spectroscopic and HR/MS data. In vitro antitrypanosomal activity and cytotoxicity against mammalian cells (L6 cell line) were evaluated for all the compounds. Santhemoidin A (13) and 3β-(2″-hydroxyisovaleroyloxy)-8β-(3-furoyloxy)costunolide (14) were the most active compounds found in this study, with IC₅₀ values of 0.10 and 0.13 μM against Trypanosoma brucei rhodesiense trypomastigotes and selectivity indices of 20.5 and 29.7, respectively.

Preparative isolation and purification of three sesquiterpenoid lactones from Eupatorium lindleyanum DC. by high-speed counter-current chromatography

A high-speed counter-current chromatography (HSCCC) method was established for the preparative separation of three sesquiterpenoid lactones from Eupatorium lindleyanum DC. The two-phase solvent system composed of n-hexane–ethyl acetate–methanol–water (1:4:2:3, v/v/v/v) was selected. From 540 mg of the n-butanol fraction of Eupatorium lindleyanum DC., 10.8 mg of 3β-hydroxy-8β-[4'-hydroxy-tigloyloxy]-costunolide, 17.9 mg of eupalinolide A and 19.3 mg of eupalinolide B were obtained in a one-step HSCCC separation, with purities of 91.8%, 97.9% and 97.1%, respectively, as determined by HPLC. Their structures were further identified by ESI-MS and ¹H-NMR.

Sesquiterpenoids isolated from Eupatorium glehnii. Isolation of guaiaglehnin A, structure revision of Hiyodorilactone B, and genetic comparison

A new sesquiterpenoid substituted with unsaturated ester, guaiaglehnin A (1), along with 15 previously known compounds, were isolated from the methanol extract of the terrestrial part of Eupatorium glehnii (Compositae) collected in Nagano Prefecture, Japan, the results of which supported the previous study by Takahashi et al. The chemical constituents of E. glehnii collected in Nagano Prefecture and those collected in Tokushima or Hokkaido are quite different, depending on collection site, although the species are identical. The base sequences of three different samples were identical. Diversity in the chemical components was detected, though no diversity existed in the DNA sequence. In this study, eupasimplicin A (2) was also isolated, whose presence in the extract of E. chinense simplicifolium was recorded but not in an article. The side chain geometry of hiyodorilactone B (5) was revised to be E.

Bioactive Sesquiterpene Lactones from Eupatorium Kiirunense

Four new sesquiterpene lactones, two heliangolides, one eudesmanolide and one germacranolide, were isolated by chromatographic fractionation of an acetone extract of Eupatorium kiirunense and named eupakirunsins F, G H and I (1–4). They were identified as 8β-(3-hydroxy-2-methylen-butanoyloxy)-1β,10α-epoxy-3α-hydroxy-6βH,7αH-heliang-4Z,11(13)-dien-6,12-olide (1), 8β-tigloyloxy-1β,10α-epoxy-3β,15-dihydroxy-6βH,7αH-heliang-4Z,11(13)-dien-6,12-olide (2), 8β-tigloyloxy-1 β,3β-dihydroxy-6βH,7αH-eudesman-4(15),11(13)-dien-6,12-olide (3) and 8βtigloyloxy-3βhydroxy-1β,10β-epoxy-14-oxo-6βH,7αH-germacra-4E,11(13)-dien-6,12-olide (4). The structures and the relative configurations of the new metabolites were elucidated through extensive spectral analysis and by comparison with known spectral data. Among the isolated compounds, 1 and 3 exhibited potent cytotoxicity against WiDr and MCF-7 human tumor cell lines.