Pharmacologically active components of viticis fructus (Vitex rotundifolia). II. The components having analgesic effects.

The extract of Viticis Fructus appeared to have an analgesic effect, and was subjected to activity-guided separation using acetic acid-induced writhing in mice. The active fraction gave new compounds, vitexfolin A (1A), B and C, 10-O-vanilloylaucubin (3), dihydrodehydrodiconiferylalcohol-beta-D- (2'-O-p-hydroxybenzoyl)glucoside (4), and vanilloyl-beta-D-(2'O-p-hydroxybenzoyl)glucoside, together with agnuside (2) and erythro- and threoguaiacylglycerols. Compounds 1A and 2-4 showed significant writhing inhibition following oral administration at doses of 15, 50, 25, and 50 mg/kg, respectively. The effect on pressure pain threshold was tested using compounds 1A and 2 at a dose of 50 mg/kg, and only the former produced the analgesia. The analgesic effect of some related iridoid glucosides is also discussed.