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

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 µg/mL of C. sinensis solvent extract. C. sinensis also exhibited a dose-dependent inhibition of encystation, with a marked cysticidal activity at 2500-5000 µg/mL concentrations. Two constituents of C. sinensis , namely epigallocatechin-3-gallate and caffeine, significantly inhibited trophozoite replication and encystation at 100 μM and 200 μM, respectively. Cytotoxicity analysis showed that 156.25 - 2500 µg/mL of solvent extract was not toxic to human corneal epithelial cells, while up to 625 µg/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. ![Figure][1] ### Competing Interest Statement The authors have declared no competing interest. [1]: pending:yes