Bioassay-guided isolation of the antinociceptive compounds motiol and beta-sitosterol from Scorzonera latifolia root extract.

Scorzonera latifolia (Asteraceae) is a plant widely distributed in Central and East Anatolia. A mastic, named yaki sakizi, is prepared from the latex and roots of S. latifolia and similar species. This latex is used in Turkish folk medicine for its analgesic activity, as anthelmintic and against infertility. The aim of this study was to isolate the compounds responsible for the antinociceptive activity of S. latifolia using bioassay-guided fractionation. The methanolic extract of the S. latifolia roots was prepared and subjected to chromatographic purification. Isolated active compounds were identified by means of MS and NMR techniques. Writhing and tail-flick tests were used to determine antinociceptive activity. Motiol and beta-sitosterol were isolated as compounds with promising antinociceptive activity. It is suggested that antinociceptive activity of the plant extract is probably caused by the synergic interaction of the isolated compounds.