Iridoid and Aromatic Glycosides from Scrophularia ningpoensisHemsl. and Their Inhibition of [Ca2+]i Increase Induced by KCl

AbstractBioassay‐guided fractionation of EtOH extract of the roots of Scrophularia ningpoensis Hemsl. resulted in the isolation of three new iridoid glycosides, i.e., 6″‐O‐caffeoylharpagide (1), 6″‐O‐feruloylharpagide (2), and 6″‐O‐β‐glucopyranosylharpagoside (3), and five new aromatic glycosides, i.e., 2‐(3‐hydroxy‐4‐methoxyphenyl)ethyl O‐α‐arabinopyranosyl‐(1→6)‐O‐α‐rhamnopyranosyl‐(1→3)‐O‐β‐glucopyranoside (4), phenyl O‐β‐xylopyranosyl‐(1→6)‐O‐β‐glucopyranoside (5), 3‐methylphenyl O‐β‐xylopyranosyl‐(1→6)‐O‐β‐glucopyranoside (6), 6‐O‐cinnamoyl β‐fructofuranosyl‐(2→1)‐O‐α‐glucopyranosyl‐(6→1)‐O‐α‐glucopyranoside (7), and 6‐O‐feruloyl β‐fructofuranosyl‐(2→1)‐O‐α‐glucopyranosyl‐(6→1)‐O‐α‐glucopyranoside (8), together with four known compounds, i.e., 6″‐O‐α‐D‐galactopyranosyl harpagoside (9), 6″‐O‐(p‐coumaroyl) harpagide (10), harpagoside (11), and angoroside C (12). Activity of the isolated compounds on [Ca2+]i increase induced by KCl was evaluated on rat cardiac myocytes using confocal laser scanning microscopy. Iridoid glycosides 1, 10, and 11, and aromatic glycosides 5 and 6 significantly inhibited the increase of [Ca2+]i induced by KCl at 100 μM.