Pall. ex Link Extract Reveals Amoebicidal Activity against and with Low Toxicity to Human Corneal Cells.

keratitis (AK) is a sight-threatening and difficult-to-treat ocular infection. The significant side effects of current AK treatments highlight the urgent need to develop a safe and effective AK medication. In this study, the amoebicidal activity of Pall. ex Link extract (ISE) against was examined and its specific amoebicidal mechanism was explored. ISE induced significant morphological changes in trophozoites and exhibited amoebicidal activity against and . ISE was further fractionated into five subfractions by sequential extraction with -hexane, chloroform, ethyl acetate, -butanol, and water, and their amoebicidal activities and underlying amoebicidal mechanisms were investigated. The -butanol subfraction of ISE (ISE-BuOH) displayed selective amoebicidal activity against the species with minimal cytotoxicity in human corneal cells (HCE-2). ISE-BuOH triggered apoptosis-like programmed cell death (PCD) in amoebae, characterized by DNA fragmentation, increased ROS production, and caspase-3 activity elevation. ISE-BuOH also demonstrated a partial cysticidal effect against the amoeba species. ISE-BuOH could be a promising candidate in the development of therapeutic drugs for AK.