title: In vitro schistosomicidal activity of balsaminol F and karavilagenin C.
abstract: Five cucurbitane-type triterpenes (1-5), previously isolated from the African medicinal plant Momordica balsamina, along with five ester derivatives (6-10) of karavilagenin C (2), were evaluated for their potential schistosomicidal activity against Schistosoma mansoni adult worms. The natural compounds were isolated from the ethyl acetate-soluble fraction of the methanol extract of the aerial parts of M. balsamina. In a preliminary study, a significant schistosomicidal activity was observed for both the crude methanol extract and the ethyl acetate fraction. The compounds responsible for the activity were found to be balsaminol F (1) and karavilagenin C (2) with LC50 values of 14.7 ± 1.5 and 28.9 ± 1.8 µM, respectively, after 24 h of incubation (positive control praziquantel, LC₅₀ = 1.2 ± 0.1 µM). Both compounds (1, 2), at 10-50 µM, induced significant reductions in the motor activity of the worms and significantly decreased the egg production. Furthermore, they were able (at 10-100 µM) to separate the adult worm pairs into male and female after 24 h. Compounds 3-5, bearing a sugar moiety as a substituent, and the acylated derivatives of karavilagenin C (6-10) were inactive, suggesting that the presence of free hydroxyl groups in the tetracyclic skeleton might be important for the activity. A correlation between activity and the molecular volume/weight of compounds was also found.
authors.affiliation: Research Institute for Medicines and Pharmaceutical Sciences-iMed.UL, Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: Cátia
authors.initials: C
authors.lastname: Ramalhete
authors.forename: Lizandra G
authors.initials: LG
authors.lastname: Magalhães
authors.forename: Vanderlei
authors.initials: V
authors.lastname: Rodrigues
authors.forename: Silva
authors.initials: S
authors.lastname: Mulhovo
authors.forename: Ademar A
authors.initials: AA
authors.lastname: Da Silva Filho
authors.forename: Maria-José U
authors.initials: MJ
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D005260:Female; D007928:Lethal Dose 50; D008297:Male; D016488:Medicine, African Traditional; D015394:Molecular Structure; D008970:Molecular Weight; D029775:Momordica / Q000737:chemistry*; D035261:Plant Components, Aerial / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D012550:Schistosoma mansoni / Q000187:drug effects*; D012556:Schistosomicides / Q000737:chemistry / Q000494:pharmacology*; D014315:Triterpenes / Q000494:pharmacology*
chemical_list: D010936:Plant Extracts; D012556:Schistosomicides; D014315:Triterpenes; C581195:balsaminol F; C581194:karavilagenin C