Camellia sinensis solvent extract confers trophocidal and cysticidal effects against Acanthamoeba castellanii

Abstract

Aim: We examined the anti-acanthamoebic efficacy of solvent extract of C. sinensis) and its chemical constituents against trophozoites and cysts of A. castellanii. Materials and methods: The effects of C. sinensis solvent extract on A. castellanii was investigated by using anti-trophozoite, anti-encystation, and anti-excystation assays. The solvent extract was also fractionated using Gas Chromatography and the chemical constituents of C. sinensis were tested, individually or combined, against the trophozoites. Results: Trophozoite replication was inhibited within 24-72 h with exposure to 625-5000 ug/mL of C. sinensis solvent extract. C. sinensis also exhibited a dose-dependent inhibition of encystation, with a marked cysticidal activity at 2500-5000 ug/mL concentrations. Two constituents of C. sinensis, namely epigallocatechin-3-gallate and caffeine, significantly inhibited trophozoite replication and encystation at 100 uM and 200 uM, respectively. Cytotoxicity analysis showed that 156.25-2500 ug/mL of solvent extract was not toxic to human corneal epithelial cells, while up to 625 ug/mL was not toxic to Madin-Darby Canine Kidney cells. Conclusions: This study shows the anti-acanthamoebic potential of C. sinensis solvent extract against trophozoites and cysts. Further pre-clinical studies are required to elucidate the in vivo efficacy and safety of C. sinensis solvent extract.