Resin glycosides are part of a very extensive family of secondary
metabolites known as glycolipids or lipo-oligosaccharides and are
constituents of complex resins (glycoresins) (1) unique to the morning
glory family, Convolvulaceae (2). These active principles are
responsible for the drastic purgative action of all the important
Convolvulaceous species used in traditional medicine throughout the
world since ancient times. Several commercial purgative crude drugs can
be prepared from the roots of different species of Mexican morning
glories. Their incorporation as therapeutic agents in Europe is an
outstanding example of the assimilation of botanical drugs from the
Americas as substitutes for traditional Old World remedies (3). Even
though phytochemical investigations on the constituents of these drugs
were initiated during the second half of the nineteenth century, the
structure of their active ingredients still remains poorly known for
some examples of these purgative roots. During the last two decades, the
higher resolution c- abilities of modern analytical isolation techniques
used in conjunction with pow- ful spectroscopic methods have facilitated
the elucidation of the active principles of these relevant herbal
products. This chapter describes the ethnobotanical information
associated with the p- gative morning glory species and how traditional
usages were instrumental in plant selection for chemical studies. The
advantages and limitations of available analy- cal techniques for the
isolation, puri?cation, and structure characterization of the individual
constituents of these complex glycoconjugates are also discussed.