Resin glycosides from Ipomoea murucoides and their effects on growth of Spodoptera frugiperda.
Spodoptera frugiperda is a major polyphagous pest in Mexico: it is the responsible of considerable economic loss to some agricultural crops, including Zea mays. The aim of this study was to evaluate the biological activity of two new resin glycosides (murucoidins XIX (1) and XX (2)) isolated from exudates of I. murucoides on S. frugiperda larvae. The new glycolipids (1 and 2) were incorporated into the diet and fed to first instar larvae of S. frugiperda. The survived larvae were weighed at day seven and pupae incubated until moths emerged. The fecundity of females was determined. The chemical structures of the new compounds 1 and 2 consist of a pentasaccharide core bonded to an 11-hydroxyhexadecanoic unit forming a macrolactone-type structure, with the lactonization site of the aglycone placed at C-2 of the second sugar and both compounds contain the same esterifying residues (n-dodecanoic and acetic acids). The results showed that compounds 1 and 2: did not cause significant mortality on Spodoptera frugiperda larvae but reduced larval weight, increased the time for pupation and in reaching adult stage and reduced the number of eggs laid and its viability. Compounds 1 and 2 can be considered as a protective potential against S. frugiperda larvae.