Cis stilbene

The materials used were phloroglucinol 99% (Sigma Aldrich), pluronic F127 (Sigma Aldrich), ethanol 97% (Merck), HCl 37% (J.T Baker), formaldehyde 37% (Merck), nickel (II) nitrate (Merck), cobalt (II) nitrate (Merck), diphenylacetylene 98% (Sigma Aldrich), sodium borohydride powder ≥ 98% (Sigma Aldrich), methanol 99% (Merck), cis-stilbene 96% (Sigma Aldrich), N₂ gas, H₂ gas, and deionized water.

The stilbenoid derivatives to be tested (1–19, Table 1) were isolated from natural sources or obtained commercially. The naturally occurring stilbenoids trans-resveratrol (1), pinostilbene (2), thunalbene (3), piceatannol (4), piceatannol-3’-O-β-glucopyranoside (5), batatasin III (6), pinostilbenoside (7), 1-(2,4-dihydroxyphenyl)-2-(4-hydroxyfenyl)-ethanone (10), 3,5-dimethoxystilbene (11), pterostilbene (15), pinosylvin monomethyl ether (17), and isorhapontigenin (18) were obtained from Sigma-Aldrich, synthetic compounds trans-stilbene (12), cis–stilbene (13), 4-stilbenecarboxylic acid (14), trans-α-methylstilbene (16), and 2,4,3´,5´-tetramethoxystilbene (19) were purchased from Sigma-Aldrich (Steinheim, Germany). The compounds 2-carboxyl-3-O-methyl-4´-β-d-glucopyranosyl-dihydroresveratrol (8) and 3-O-caffeoyl-(9→5)-β-apiosyl-(1→6)-β-glucopyranosyl-5,3´-O-dimethyldihydropiceatannol (9) were kindly provided by Dr. Sebastian Granica (Medical University of Warsaw, Warsaw, Poland) who had isolated them from Tragopogon tommasinii Sch.Bip. (Asteraceae, Cichorieae) [7 (link)].