Four New Acylated Iridoid Glycosides from the Aerial Part of Veronicastrum sibiricum and Their Antioxidant Response Element‐Inducing Activity

Four new ( 1 – 4 ) and one known ( 5 ) acylated iridoid glycosides were isolated from the aerial parts of Veronicastrum sibiricum (L.) Pennell . The chemical structures of the isolated compounds were determined to be 3″,4″‐dicinnamoyl‐6‐ O ‐rhamnopyranosyl‐10‐ O ‐bergaptol‐5,7‐bisdeoxycynanchoside ( 1 ), 3″,4″‐dicinnamoyl‐6‐ O‐ rhamnopyranosylpaulownioside ( 2 ), 2″,4″‐dicinnamoyl‐6‐ O ‐rhamnopyranosylcatalpol ( 3 ), 3″,4″‐dicinnamoyl‐6‐ O ‐rhamnopyranosylaucubin ( 4 ), and 3″,4″‐dicinnamoyl‐6‐ O ‐rhamnopyranosylcatalpol ( 5 ) using spectroscopic techniques. Among these compounds, compound 5 increased antioxidant response element (ARE) luciferase activity.