In Vitro Evaluation of Sida pilosa Retz (Malvaceae) Aqueous Extract and Derived Fractions on Schistosoma mansoni

Sida pilosa Retz. (Malvaceae) is a medicinal plant used in Africa for the treatment of dysmenorrhea, lower abdominal pains and intestinal helminthiasis. S. pilosa aqueous extract and derived fractions were investigated for their bioactivity against Schistosoma mansoni. The aqueous extract from S. pilosa aerial parts (1.25 - 40 mg/mL) and derived fractions (n-hexane, DCM, EtOAc and n-BuOH: 0.25 - 8 mg/mL) were tested on adult S. mansoni maintained in a GMEN culture medium. Praziquantel was used as the reference drug. After 24 h of incubation, worms were monitored for their viability and egg output. The antioxidant activity of S. pilosa was evaluated by the ability to scavenge the 2,2-diphenyl-1-picrylhydrazyl free radicals. The chemical composition of the n-BuOH fraction was investigated by HPLC-MS analysis. S. pilosa aqueous extract and fractions significantly increased worm mortality in a concentration-dependent manner. The n-BuOH fraction was the most active with a LC50 of 1.25 mg/mL. Significant reduction of motor activity (25% to 100%) was recorded for surviving worms incubated in different concentrations of the extract and fractions. Incubation of S. mansoni in different concentrations of S. pilosa extract and fractions led to significant reduction of egg laying (52% to 100%). The aqueous extract and derived fractions exhibited antioxidant activity in a concentration-dependent manner. The highest antioxidant activity was found with the EtOAc fraction, followed by the DCM and n-BuOH fractions. HPLC-MS analysis of the n-butanol fraction revealed the presence of two indoloquinoline alkaloids. This study disclosed the schistosomicidal activity of the n-butanol fraction from S. pilosa aqueous extract. This activity is probably related to the indoloquinoline alkaloids identified in the fraction.

Impact of continuous low water stage on the breeding environment of Oncomelania hupensis: a case study of Poyang Lake area in China

Background Oncomelania hupensis is the only intermediate host of Schistosoma japonicum and plays a decisive role in its transmission.The variation of water level greatly affects the reproduction and growth of snails.Therefore,in this paper,we analyze the variations of water level in the Poyang Lake region from 1993 to 2016 combined with satellite imagery to elucidate the evolution of the snail breeding environment.Methods By employing remote sensing data from 1993 to 2016(April–June and September–November),the vegetation area of Poyang Lake and the vegetation area at different elevations were extracted and calculated.Moreover,the average daily water level data from the four hydrological stations(Hukou station,Xingzi station,Tangyin station and Kangshan station)which represent the typical state of Poyang Lake were collected from 1993 to 2016.The variance of the monthly mean water level,inundation time and the average area were analyzed by variance to find a significance level ofα=0.05.Results According to hydrological data before and after 2003,the average water level after 2003 is significantly lower than that before 2003 in Poyang Lake.After 2003,the time of inundateing the snail breeding period was later in April to June than that before 2003,while the time of wate-falling stage in September to November moved forward after 2003 than before 2003.Of them,the lowest water level affecting the breeding and growing period of O.hupensis in the northern part of Poyang Lake decreased from 11 m to 9 m.After 2003,the expansion of meadow area in the north part of Poyang Lake was mainly concentrated in the elevation of 9–11 m,and the newly increased infested-meadow in the lake area was mainly concentrated in the north part of Poyang Lake.Conclusions By comparing the change of water level characteristics in different parts of the Poyang Lake area as well as changes in meadow area before and after 2003,it is found that the water level changes mainly affect the snail breeding area in the northern part of Poyang Lake.The results are helpful for improving scientific measures for snail control in Jiangxi Province.This approach could also be applicible to Dongting Lake area and other lake areas affected by water level changes and can bring significant guidance for snail control in lake areas.