Antitrypanosomatid activity of flavonoid glycosides isolated from Delphinium gracile, D. staphisagria, Consolida oliveriana and from Aconitum napellus subsp. Lusitanicum

Abstract

This work describes the isolation and structure elucidation of two new acylated quercetin tetraglycosides (compounds 1 and 2) from Delphinium gracile and their antiparasitic study with other twelve compounds from D. gracile (compounds 3–8), D. staphisagria (compound 9), Consolida oliveriana (compounds 10–12) and Aconitum napellus subsp. Lusitanicum (compounds 13–14). The in vitro results against the extracellular and intracellular stages of three Leishmania spp. and T. cruzi showed that all the compounds tested had selectivity indexes higher than that of the reference drug benznidazole (BZN) against T. cruzi. However, they had higher effectiveness as antileishmanicidal agents and some of them met the standards for the three Leishmania species and had a higher selectivity index than the reference drug (glucantime). The changes in metabolite excretion by 1H NMR and the ultrastructural alterations by transmission electron microscopy (TEM) from treated parasites revealed that the severe modifications generated in organelles such as glycosomes or mitochondria by the compounds could be the ultimate reasons for the alterations detected in the differences of the excretion products of all the species. The activity, stability, low cost of starting materials, and straightforward synthesis make flavonoid derivatives appropriate molecules for the developing of an affordable anti-leishmanicidal agent.