A new indole glycoside from the seeds of Raphanus sativus

A new indole glycoside, beta-d-glucopyranosyl 2-(methylthio)-1H-indole-3-carboxylate, named raphanuside A (1), as well as eight known compounds, beta-d-fructofuranosyl-(2 -> 1)-(6-O-sinapoyl)-alpha-d-glucopyranoside (2), (3-O-sinapoyl)-beta-d-fructofuranosyl-(2 -> 1)-alpha-d-glucopyranoside (3), (3-O-sinapoyl)-beta-d-fructofuranosyl-(2 -> 1)-(6-O-sinapoyl)-alpha-d-glucopyranoside (4), (3,4-O-disinapoyl)-beta-d-fructofuranosyl-(2 -> 1)-(6-O-sinapoyl)-alpha-d-glucopyranoside (5), isorhamnetin 3,4'-di-O-beta-d-glucoside (6), isorhamnetin 3-O-beta-d-glucoside-7-O-alpha-l-rhamnoside (7), isorhamnetin 3-O-beta-d-glucoside (8) and 3'-O-methyl-(-)-epicatechin 7-O-beta-d-glucoside (9) were isolated from the seeds of Raphanus sativus. Furthermore, compounds 1-3 and 6-9, were isolated from this plant for the first time. The structures of compounds 1-9 were identified using 1D and 2D NMR, including H-1-H-1 COSY, HSQC, HMBC and NOESY spectroscopic analyses. The inhibitory activity of these isolated compounds against interleukin-6 (IL-6) production in TNF-alpha stimulated MG-63 cells was also examined.