OBJECTIVE: To study the antiamoebic effects of four novel synthetic dihydropyridine (DHP) compounds against Acanthamoeba castellanii belonging to the T4 genotype. Furthermore, to evaluate their activity against amoeba-mediated host cells cytopathogenicity as well as their cytotoxicity against human cells.
METHODS: Dihydropyridines were synthesized by cyclic dimerization of alkylidene malononitrile derivatives. Four analogues of functionally diverse DHPs were tested against Acanthamoeba castellanii by using amoebicidal, encystation and excystation assays. Moreover, Lactate dehydrogenase assays were carried out to study cytopathogenicity and cytotoxicity against human cells.
RESULTS: These compounds showed significant amoebicidal and cysticidal effects at 50 μM concentration, whereas, two of the DHP derivatives also significantly reduced Acanthamoebamediated host cell cytotoxicity. Moreover, these DHPs were found to have low cytotoxicity against human cells suggesting a good safety profile.
CONCLUSION: The results suggest that DHPs have potential against Acanthamoeba especially against the more resistant cyst stage and can be assessed further for drug development.
AIM OF THE STUDY: In this context, supported with previous preliminary data of its antiplasmodial activity, this study was undertaken to determine the in vitro antiplasmodial and cytotoxicity activities of G. lanceolatus crude extracts and its major compounds.
MATERIALS AND METHODS: The in vitro antiplasmodial activity was determined by parasite lactate dehydrogenase (pLDH) assay on chloroquine-sensitive (3D7) and chloroquine-resistant (K1) strains of Plasmodium falciparum. The cytotoxicity activity was evaluated using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on hepatocellular carcinoma (HepG2) and normal liver (WRL-68) cell lines.
RESULTS: The root methanol extract possessed potent antiplasmodial activity against both P. falciparum 3D7 and K1 strains (IC50 = 2.7 μg/ml, SI = 140; IC50 = 1.7 μg/ml, SI = 236). Apart from the DCM extract of stem bark and root that were found to be inactive (IC50 > 50 μg/ml) against 3D7 strain, all other tested crude extracts exhibited promising (5< IC50 cell lines (CC50 > 30 µg/ml, CC50 > 10 µM, respectively), except for the hexane and DCM extracts of root, which exerted mild cytotoxicity on HepG2 cell line (IC50