Antiprotozoal potential of against three virulent subtypes of sp.

sp. is a group of anaerobic protozoa parasitizing the gastrointestinal tract of humans and a broad variety of animals. Evidences of parasites resistance development to antiprotozoal drugs urge the exploration of new therapeutics. Antiprotozoal potential of , a medicinal plant traditionally used for oral hygiene, was evaluated in vitro against sp. human isolates. Until now, no study has described the effect of . extracts on this parasitic protozoa. sp. positive stool samples collected from patients with gastrointestinal complaints and asymptomatic individuals diagnosed by microscopy were furthermore cultured in vitro and characterized by PCR and multiplex-PCR using sequence-tagged-site primers to determine their subtypes. Out of 21 sp. isolates, five were determined as ST1, 14 as ST3, and two as ST5 subtypes. Antiprotozoal activity of untreated and heat-treated . roots aqueous extracts was evaluated in vitro by serial dilutions on three sp. subtypes; ST1, ST3, and ST5 isolated from symptomatic patients. A significant killing activity was observed with both, untreated and heat-treated aqueous extracts of . at minimal concentration of 2.5 μl/ml compared to parasites' growth controls ( < 0.05). Maximal antiprotozoal effect was reached at a concentration of 20 µl/ml of . aqueous extract. Means of growth inhibition effect obtained with untreated and heat-treated extracts at 40 µl/ml against the three subtypes of sp. were 80% (SD 2.3) and 82% (SD 1.1), respectively. No significant difference was observed in the inhibitory effect of . extracts between the three sp. subtypes. Aqueous extract of . roots contains therefore heat-stable components with significant antiprotozoal activity against sp. subtypes ST1, ST3, and ST5 in vitro. Further investigations are required to determine and characterize the active antiprotozoal components of . roots and their evaluation in vivo.