Iridoid glycosides from the leaves of <i>Paederia foetida</i> and their antinociceptive activities

A chemical investigation on the leaves of <i>Paederia Foetida</i> resulted into the isolation of two new iridoid glycosides, paefoetines A and B (<b>1</b> and <b>2</b>). Structural elucidation of all the compounds was performed by spectral methods such as 1D and 2D (¹H<i>-</i>¹H COSY, HMQC, and HMBC) NMR spectroscopy. The two isolated iridoid glycosides were tested <i>in vivo</i> for their antinociceptive properties. As a result, <b>1</b> exhibited potent antinociceptive activity and its ED₅₀ value (49.2 μmol/kg) was twofold less than those of the positive control drugs aspirin.