Avaliação do potencial esquistossomicida da arctiina, extraída de Arctium lappa L.

Abstract

Schistosomiasis is one of the most significant neglected tropical diseases in the world. Only one drug is currently available for the treatment and control of schistosomiasis, therefore there is an urgent need for the development of new schistosomicide compounds, being natural products an important source of these molecules. Hence, in this work we studied the lignan arctiin extracted from Arctium lappa species, whose anti-inflammatory and antiproliferative functions have been previously described. Our aim was to investigate in vitro and in vivo its schistosomicidal activity. We tested the compound in vitro at the follow concentrations 30, 60, 120 and 240 ug/ml. There was no difference in all tested concentrations in the viability of the parasite in the culture after the incubation when compared to the control group. In addition we verified the plasmatic concentration of arctiin after intraperitoneal administration in mice by chromatographic analysis. The analysis of pure arctiin diluted in either methanol or mouse plasma showed a peak in the chromatogram at retention time of 5 minutes, absorbance was measured at 254 nm. Animal plasma sample collected one hour after treatment with arctiin was analyzed under same experimental conditions and revealed a similar peak, confirming the availability of arctiin in the plasma following administration. The in vivo tests were performed in Swiss female mice, those were intraperitoneally injected with two dosages of arctiin (50 mg/kg) - the first administered 20 days after infection and the second two weeks later. The follow parameters were analyzed: liver weight, white blood cell count, parasitic load and oogram. We did not find any significant change in those parameters comparing infected control groups treated either with praziquantel (200 mg / kg) or dimethyl sulfoxide (0.5 %) to the group treated with arctiin. The most promising result was the reduction around 20% of the average area of the granuloma in the arctiin group compared with the infected control. More studies are needed to verify possible mechanisms of action of this molecule in inflammatory components that play a role in granuloma formation.