Antinociceptive iridoid glycosides from the aerial parts of Paederia foetida

Two previously undescribed iridoid glycosides, 6'-O-trans-feruloyl-(4S,6R)-3,4-dihydro-3β-ethoxypaederoside (1) and 6'-O-trans-caffeoyl-(4S,6R)-3,4-dihydro-2'-O-3α-paederoside (2), were isolated from the 90% EtOH extract of the air dried aerial parts of Paederia Foetida. Structural elucidation of all the compounds was performed by spectral methods such as 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy. The two isolated iridoid glycosides were tested in vivo for their antinociceptive properties. As a result, 2 showed potent antinociceptive effect and its ID50 value (53.4 μmol/kg) was 2-fold less than those of the positive control drugs aspirin and acetaminophen.