Iridoid Glycosides and Phenolic Compounds from the Flowers of Vitex agnus‐castus

A new and rare type of iridoid glycoside, agnusoside ( 1 ), a new caffeoylquinic acid derivative, castusic acid ( 2 ), and a new sugar ester, 1,2‐di‐(4‐hydroxybenzoyl)‐ β ‐glucopyranose ( 3 ), along with ten known compounds belonging to iridoid glycosides (agnuside, trans ‐eurostoside), caffeoylquinic acid derivatives (chlorogenic acid and isochlorogenic acid A), flavonoids (isoorientin, isovitexin, kaempferol 3‐ O ‐sophoroside, luteolin 6‐ C ‐(2′′‐ O ‐ trans ‐caffeoyl)glucopyranoside, and simple phenolic acids (4‐hydroxybenzoic acid, 3,4‐dihydroxybenzoic acid), chemical classes were isolated from the flowers of Vitex agnus‐castus . The structures of the isolates were established by extensive 1D‐ and 2D‐ NMR spectroscopic analysis as well as HR ‐ ESI ‐ MS . Agnusoside ( 1 ) represents an unusual type of iridoid glycoside with its 6‐keto C(4) nonsubstituted aglycone.