METHODS: Three different varieties of CoNPs were synthesized by utilizing hydrothermal and ultrasonication methods and were thoroughly characterized by X-ray diffraction and field emission scanning electron microscopy. Amoebicidal, encystation, excystation, and host cell cytopathogenicity assays were conducted to study the antiacanthamoebic effects of CoNPs.
RESULTS: The results of the antimicrobial evaluation revealed that cobalt phosphate Co3(PO4)2 hexagonal microflakes, and 100 nm large cobalt hydroxide (Co(OH)2) nanoflakes showed potent amoebicidal activity at 100 and 10 µg/ml against Acanthamoeba castellanii as compared to granular cobalt oxide (Co3O4) of size 35-40 nm. Furthermore, encystation and excystation assays also showed consistent inhibition at 100 µg/ml. CoNPs also inhibited amoebae-mediated host cell cytotoxicity as determined by lactate dehydrogenase release without causing significant damage to human cells when treated alone.
CONCLUSIONS: To our knowledge, these findings determined, for the first time, the effects of composition, size and morphology of CoNPs against A. castellanii. Co3(PO4)2 hexagonal microflakes showed the most promising antiamoebic effects as compared to Co(OH)2 nanoflakes and granular Co3O4. The results reported in the present study hold potential for the development of antiamoebic nanomedicine.
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.