Sylvestroside I may have analgesic effect.

The isolation of five iridoids and bis-iridoids identified as secologanin (I), swerosidic acid (II), secoxyloganin (III), Sylvestroside I (IV) and Sylvestroside III (V) from Acicarpha tribuloides Juss. (Calyceraceae). Also, the pharmacological profile of the extracts (Petroleum ether, CHCl 3, CHCl 3 /MeOH (9:1), MeOH and n-BuOH) from A. tribuloides was studied both in vivo and in vitro experiments. The in vivo experiments indicate that CHCl 3 /MeOH, MeOH and n-BuOH (100, 50 and 10 mg/kg/po) induce a significative analgesic effect in mice whereas CHCl 3 and petroleum ether extracts were inactive. In the in vitro experiments the extracts showed a similar activity because CHCl 3 /MeOH, MeOH and n-BuOH (500,250 and 125 μg/ml) were able to reduce the electrically induced contractions of guinea-pig ileum whereas CHCl 3 and petroleum ether extracts did not.