Three new and five known sesquiterpene lactones were isolated from the roots of Laser trilobum (L.) Borkh. Chemical identity of the known compounds and structural analysis of the new ones were determined by HR MS and NMR spectroscopy. The two new sesquiterpene lactones: 2-acetoxytrilobolide and 2-hydroxy-10-deacetyltrilobolide belong to the guaianolide type, and the third one, eudeslaserolide, to the biogenetically related eudesmanolide type. Both types, together with their biogenetic precursor of germacranolide type (laserolide) are present in L. trilobum, as well as in the related Laserpitium species. Purposefully selected set of these native sesquiterpene lactones was tested for specific immunobiological properties. The obtained results demonstrate that trilobolide and its acetoxy analog are strong activators of cytokine secretion. On the contrary, the other L. trilobum and Laserpitium siler constituents are only very mild activators, or even inhibitors of the cytokine and nitric oxide production.
Resveratrol and closely related stilbenoids belong to the most intensively studied biologically active compounds. This interest evoked several attempts to prepare such compounds in a convenient synthetic way. Our approach allowed obtaining largely methoxystilbenes, formed as E-isomers only (using Wittig–Horner synthesis as the key step), which were further demethylated by boron tribromide. The hydroxymethoxystilbenes (e.g. pterostilbene) were prepared using isopropyl protection, later selectively deprotected by boron trichloride. The method is suitable for preparing such compounds in a large amount. Effects of the obtained stilbene derivatives on immunobiological responses triggered by lipopolysacharide and interferon-γ were tested under in vitro conditions. Namely production of nitric oxide (NO) was investigated, and relation between the molecular structure and immunobiological activity was assessed.
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