Camellia sinensis solvent extract, epigallocatechin gallate and caffeine confer trophocidal and cysticidal effects against Acanthamoeba castellanii

We examined the anti-acanthamoebic efficacy of green tea Camellia sinensis solvent extract (SE) or its chemical constituents against Acanthamoeba castellanii by using anti-trophozoite, anti-encystation, and anti-excystation assays. C. sinensis SE (625-5000 mu g/mL) inhibited trophozoite replication within 24-72 h. C. sinensis SE exhibited a dose-dependent inhibition of encystation, with a marked cysticidal activity at 2500-5000 mu g/mL. Two constituents of C. sinensis, namely epigallocatechin-3-gallate and caffeine, at 100 mu M and 200 mu M respectively, significantly inhibited both trophozoite replication and encystation. Cytotoxicity analysis showed that 156.25-2500 mu g/mL of SE was not toxic to human corneal epithelial cells, while up to 625 mu g/mL was not toxic to Madin-Darby canine kidney cells. This study shows the anti-acanthamoebic potential of C. sinensis SE against A. castellanii trophozoites and cysts. Pre-clinical studies are required to elucidate the in vivo efficacy and safety of C. sinensis SE.

Automated summary

We investigated the anti-acanthamoebic effect of green tea Camellia sinensis solvent extract and its chemical components against Acanthamoeba castellanii. The extract and two specific components, epigallocatechin-3-gallate and caffeine, were found to inhibit both the replication and encystation of the parasite. The extract did not show cytotoxicity to human corneal epithelial cells and Madin-Darby canine kidney cells. Further pre-clinical studies are needed to evaluate the efficacy and safety of the extract in vivo.