title: Screening of marine extracts for schistosomicidal activity in vitro. Isolation of the triterpene glycosides echinosides A and B with potential activity from the Sea Cucumbers Actinopyga echinites and Holothuria polii.
abstract: BACKGROUND
  Praziquantel (PZQ) is the drug available for the treatment of schistosomiasis. The reported reduced cure rates, the failure of treatment after PZQ administration in patients and the existence of resistant parasite strains, reinforce the need to rapidly discover new effective molecules against Schistosoma parasite.
  
  
  OBJECTIVE
  To screen the methanol extracts of 79 marine organisms for their schistosomicidal activities against Schistosoma mansoni adult worms in vitro and perform bio-assay directed chromatography for the most active extracts to isolate the active compounds.
  
  
  METHODS
  Screening of the marine organisms and bio-assay directed chromatography of the most active extracts together with identification of the active isolates using 1D and 2D NMR analysis, were investigated.
  
  
  RESULTS
  RESULTS indicated that the isolates echinosides A and B from the sea cucumbers Actinopyga echinites Jaeger and Holothuria polii Delle Chiaie (Holothuriidae) were highly active. Their LC(50) values were equal to 0.19 μg/ml and 0.27 μg/ml, respectively. Detailed (1)HNMR data for echinosides A and B are reported here for the first time.
  
  
  CONCLUSIONS
  These findings demonstrate that the isolated echinosides possess potential in vitro schistosomicidal activity against S. mansoni adult worms. Therefore, echinosides are promising as lead compounds for the development of new schistosomicidal agents.
authors.affiliation: Natural Compounds Department, National Research Center, Giza, Egypt. frmelek@hotmail.com
authors.forename: Farouk R
authors.initials: FR
authors.lastname: Melek
authors.forename: Menerva M
authors.initials: MM
authors.lastname: Tadros
authors.forename: Fouad
authors.initials: F
authors.lastname: Yousif
authors.forename: M A
authors.initials: MA
authors.lastname: Selim
authors.forename: Marwa H
authors.initials: MH
authors.lastname: Hassan
mesh_terms: D000818:Animals; D001681:Biological Assay; D002845:Chromatography; D047332:Holothuria; D006697:Holothurin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol / Q000737:chemistry; D015394:Molecular Structure; D012550:Schistosoma mansoni / Q000187:drug effects* / Q000254:growth & development; D012556:Schistosomicides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D012616:Sea Cucumbers / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry
chemical_list: D012556:Schistosomicides; D012997:Solvents; D006697:Holothurin; C048552:echinoside B; C043973:echinoside A; D000432:Methanol