The influence of some xanthone derivatives on the activity of J-774A.1 cells

The chemiluminescence of stimulated cells with phorbol myristate acetate and the production of nitric oxide after stimulation with lipopolisaccharide in the presence of the parent compounds FAA (flavone-8-acetic acid = (4-oxo-2- phenyl-4H-chromen-8-yl)acetic acid), XAA (xanthone-4-acetic acid = (9-oxo-9Hxanthen-4-yl)acetic acid), and appropriate xanthone derivatives (1-7) was determined. Also the toxicity of the FAA, MFAA ((6-methyl-4-oxo-2-aryl-4Hchromen-8-yl)acetic acid), XAA and 1–7 against J-774A.1 cultured cells was evaluated. Compound 5 (2-methyl-2-{[(9-oxo-9H-xanthen-2-yl)methyl]sulfanyl}- propanoic acid) was effective in inhibiting chemiluminescence of J-774A.1 cells but most of the other tested compounds stimulated the reaction. FAA and two xanthones with a methoxycarbonyl moeity slightly decreased the generation of nitric oxide at 50 μM. Most of the tested compounds (1-7) showed weak toxicity at concentration of 100 μM

Sesquiterpene lactones from Lactuca canadensis and their chemotaxonomic significance

A total of 19 sesquiterpene lactones were isolated from roots of Lactuca canadensis L., of which 10 were reported for the first time from Lactuca species and two were unknown. This is also the first report on the co-occurrence of three pairs of zaluzanin C-type guaianolides, epimeric at C-3, and on the presence of six eudesmanolides, oxygenated at C-1 and C-3, in Lactuca species. The new compounds were characterized as 3-epizaluzanin C-3- O - b -glucopyranoside and 11,13-dehydrolactuside C using 1D and 2D NMR and high resolution mass spectroscopy. The sesquiterpene lactone profile of this species is dominated by zaluzanin C-type guaianolides (9 compounds) and eudesmanolides (8 compounds). The dissimilarity of this profile compared to that of other taxa of the genus is discussed