Acanthamoeba is an opportunistic protozoan pathogen and known to be one of the most ubiquitous organisms, having a potential role in ecosystem and recognized to cause blinding keratitis and rare but fatal granulomatous encephalitis involving the central nervous system with a very poor prognosis. This is due to limited availability of effective anti-Acanthamoeba drugs. Here Acanthamoebacastellanii (T1 and T4 genotypes)were used to demonstrate the effects of various in house synthesized pharmaceutical compounds, nanoparticles and herbal extracts on pathogenic properties of Acanthamoeba. Using human brain microvascular endothelial cells (HBMEC) adhesion, cytotoxicity and amoebae viability assays were performed.Using HBMEC, Acanthamoeba exhibited swear toxicity and binding to the host cells, which was reduced in the presence of all tested compounds with optimal effects of extracts (Peganum harmala). It is further demonstrated that extracts exhibited optimal amoebicidal effects. The residual sub population lost their viability for over longer incubation. It is worthy to note that the ability of Acanthamoeba cyst-formation to escape death by transforming into a cyst form,that is resistant to harsh physiological, environmental and pharmacological conditions but in the current nanoparticles (TiO2) treatment Acanthamoeba trophozoites could not underwent encystment which is found quite novel and interesting. Furthermore, Polyoxometalates also exhibited the amoebicidal effects in vitro. Overall, we have shown the inhibitory effects of pharmaceutical compounds, nanoparticles and herbal extracts but herbal extracts have shown the optimal damaging effects on amoeba with minimal toxicity to HBMEC in vitro. Further studies will examine the use of fractionalize herbal compounds with functionalized nanoparticles to scrutinize the potential candidate of anti-amoebic drug delivery system in vivo model system.

Keywords: Acanthamoeba, Human brain microvascular endothelial cells, Adhesion, Cytotoxicity, Amoebicidal effects, Encephalitis

Abbreviations: Human Brain Microvascular Endothelial Cells (HBMEC)