Chemoprevention of Schistosomiasis: In vitro Antiparasitic Activity of Nineteen Plant-derived and Synthetic Simple Naphthoquinones and Naphthols against Schistosoma Mansoni Adult Worms
- *Corresponding Author:
- Lizandra Guidi Magalhães
Research Group on Natural Products
Center for Research in Sciences and Technology
University of Franca, Franca, 14404 600
São Paulo, Brazil
E-mail: [email protected]
Received Date: July 20, 2014; Accepted Date: July 23, 2014; Published Date: August 12, 2014
Citation: Magalhães LG, Subba Rao G, Soares IAO, Badocco FR, Cunha WR, et al. (2014) Chemoprevention of Schistosomiasis: In vitro Antiparasitic Activity of Nineteen Plant-derived and Synthetic Simple Naphthoquinones and Naphthols against Schistosoma Mansoni Adult Worms. J Trop Dis 2:146. doi: 10.4172/2329-891X.1000146
Copyright: © 2014 Magalhães LG, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Schistosomiasis, a debilitating disease dating back to ancient times, is currently endemic in 78 tropical and subtropical countries with 243 million people requiring treatment. Current treatment of schistosomiasis depends primarily on a single drug, praziquantel which is less effective against larval stage of the parasite and has potential for development of resistance. Thus, there is urgent need for development of new, effective and inexpensive antischistosomal drugs. Simple naphthoquinone (NAPQ) secondary metabolites in plants are known to act as phytotoxins in preventing bacterial, fungal and parasitic attacks. The present study reports antischistosomal activity of nineteen plant-derived and synthetic simple NAPQs and naphthols against Schistosoma mansoni adult worms under in vitro conditions. Four of the tested compounds met the WHO’s Special Program for Research and Training in Tropical Diseases (TDR) in vitro criterion for “hit” and lead compound (100% mortality of adult worms at a concentration of ≤ 5 µg/ml when incubated for 48 h): plant-derived naphthazarin, two synthetic NAPQs, 1, 4-NAPQ and 2-methy-1, 4-NAPQ (menadione) and synthetic 1-amino-2-naphthol hydrochloride. Structure-antischistosomal activity studies with 1, 4-NAPQs indicated the importance of the number and position of hydroxyl and methyl groups, particularly at C-2, C-5 and C-8 positions of the parent NAPQ molecule, which play important role in stabilizing quinone moiety and formation of reactive oxygen species essential for antiparasitic effect. The results call for further in vivo studies on the chemopreventive potential of plant-derived naphthazarin and synthetic 1,4-NAPQ, menadione and 1-amino-2-naphthol, all of which have met the WHO/TDR in vitro criterion for their consideration as lead schistosomicidal candidates.