Iridoid and Aromatic Glycosides from Scrophularia ningpoensis Hemsl . and Their Inhibition of [Ca 2+ ] i Increase Induced by KCl

Bioassay‐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 [Ca 2+ ] 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 [Ca 2+ ] i induced by KCl at 100 μ M .