ABSTRACT
Bioassay-guided fractionation of the methanol extract of aerial parts from Helianthemum glomeratum afforded five antiprotozoal flavonol glycosides: tiliroside, kaempferol-3-O-(3'',6''di-O-E-p-coumaroyl)-betad-glucopyranoside, astragalin, quercitrin and isoquercitrin. The in vitro antiprotozoal assay showed that tiliroside was the most potent antiamoebic and antigiardial compound with IC(50) values of 17.5 microg/mL for Entamoeba histolytica and 17.4 microg/mL for G. lamblia. Isoquercitrin showed selectivity against E. histolytica (IC(50) 14.7 microg/mL) and quercitrin toward G. lamblia (IC(50) 24.3 microg/mL). All isolated compounds were less active than metronidazole and emetine, two antiprotozoal drugs used as positive controls.
Subject(s)
Antiprotozoal Agents/pharmacology , Cistaceae , Phytotherapy , Plant Extracts/pharmacology , Animals , Antiprotozoal Agents/administration & dosage , Antiprotozoal Agents/therapeutic use , Entamoeba histolytica/drug effects , Flavonols/administration & dosage , Flavonols/pharmacology , Flavonols/therapeutic use , Giardia lamblia/drug effects , Glycosides/administration & dosage , Glycosides/pharmacology , Glycosides/therapeutic use , Parasitic Sensitivity Tests , Plant Components, Aerial , Plant Extracts/administration & dosage , Plant Extracts/therapeutic useABSTRACT
Extraction of the aerial parts of Rubus coriifolius, a medicinal plant used by the Maya communities in Southern Mexico to treat bloody diarrhoea, resulted in the isolation of seven known compounds (-)-epicatechin, (+)-catechin, hyperin, nigaichigoside F1, beta-sitosterol 3-O-beta-d-glucopyranoside, gallic acid and ellagic acid. All compounds were tested for their antiprotozoal activity against Entamoeba histolytica and Giardia lambia. Epicatechin was the main responsible for the antiprotozoal activity of the extract against both protozoa, its activity was comparable to emetine, but no exceeded that of metronidazole.
