Ethnobotany in the search for vasoactive herbal medicines.

Plant samples derived from ethno-directed and random collections were screened to determine their effect on pre-contracted rat aortic tissue. Of the 31 ethno-directed species, four were found to be potent relaxants of vascular smooth muscle. The vasoactive species were Chamguava gentlei, Alseis yucatanensis, Licaria peckii and Nectandra salicifolia. None of the 32 randomly collected samples produced a relaxation response. These data support the hypothesis that ethno-directed collection is a more efficient means of drug discovery than random plant screens.