Discovery of Antischistosomal Drug Leads Based on Tetraazamacrocyclic Derivatives and Their Metal Complexes.
Praziquantel (PZQ) is the only drug available for the treatment of schistosomiasis, and since its large-scale use might be associated with the onset of resistance, new antischistosomal drugs should be developed. A series of 26 synthetic tetraazamacrocyclic derivatives and their metal complexes were synthesized, characterized, and screened for antischistosomal activity by application of a phased screening program. The compounds were first screened against newly transformed schistosomula (NTS) of harvested Schistosoma mansoni cercariae, then against adult worms, and finally, in vivo using the mouse model of S. mansoni infection. At a concentration of 33 μM, incubation with a total of 12 compounds resulted in the mortality of NTS at the 62% to 100% level. Five of these showing 100% inhibition of viability of NTS at 10 μM were selected for further screening for determination of the 50 inhibitory concentrations (IC50s) against both NTS and adult worms. Against NTS, all 5 compounds showed IC50s comparable to the IC50 of the standard drug, PZQ (0.87 to 9.65 μM for the 5 compounds versus 2.20 μM for PZQ). Three of these, which are the bisquinoline derivative of cyclen and its Fe(2+) and Mn(2+) complexes, showed micromolar IC50s (1.62 μM, 1.34 μM, and 4.12 μM, respectively, versus 0.10 μM for PZQ) against adult worms. In vivo, the worm burden reductions were 12.3%, 88.4%, and 74.5%, respectively, at a single oral dose of 400 mg/kg of body weight. The Fe(2+) complex exhibited activity in vivo comparable to that of PZQ, pointing to the discovery of a novel drug lead for schistosomiasis.
College of Pharmacy, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA khanmo@marshall.edu tim.hubin@swosu.edu.
M O Faruk
MO
Khan
Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland University of Basel, Basel, Switzerland.
Jennifer
J
Keiser
College of Pharmacy, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA.
P N A
PN
Amoyaw
College of Pharmacy, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA.
Mohammad F
MF
Hossain
Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland University of Basel, Basel, Switzerland.
Mireille
M
Vargas
Department of Chemistry, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA.
Justin G
JG
Le
Department of Chemistry, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA.
Natalie C
NC
Simpson
Department of Chemistry, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA.
Kimberly D
KD
Roewe
Department of Chemistry, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA.
TaRynn N Carder
TN
Freeman
Department of Chemistry, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA.
Travis R
TR
Hasley
Department of Chemistry, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA.
Randall D
RD
Maples
Department of Chemistry and Positron Emission Tomography Research Centre, University of Hull, Hull, United Kingdom.
Stephen J
SJ
Archibald
Department of Chemistry, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA khanmo@marshall.edu tim.hubin@swosu.edu.
Timothy J
TJ
Hubin
D000818:Animals; D002413:Cations, Divalent; D058487:Cercaria / Q000187:drug effects / Q000254:growth & development; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000494:pharmacology*; D055808:Drug Discovery; D005260:Female; D006571:Heterocyclic Compounds / Q000138:chemical synthesis / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D007501:Iron / Q000737:chemistry; D008345:Manganese / Q000737:chemistry; D051379:Mice; D009942:Organometallic Compounds; D011223:Praziquantel / Q000494:pharmacology; D011804:Quinolines / Q000138:chemical synthesis / Q000494:pharmacology*; D012550:Schistosoma mansoni / Q000187:drug effects* / Q000254:growth & development; D012555:Schistosomiasis mansoni / Q000188:drug therapy* / Q000469:parasitology; D012556:Schistosomicides / Q000138:chemical synthesis / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D002413:Cations, Divalent; D056831:Coordination Complexes; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D011804:Quinolines; D012556:Schistosomicides; D008345:Manganese; D011223:Praziquantel; D007501:Iron