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Acanthamoeba is a free-living amoeba causing a potentially blinding infection of the cornea. Acanthamoeba keratitis is difficult to treat, without total efficacy in some patients because of cysts that are less susceptible than trophozoites to the usual treatments. Contact lens wearers are most at risk and account for some 95% of cases. Cationic steroid antibiotic (CSA)-13 is a small molecule aminosterol that has been shown to mimic the activity of endogenous antimicrobial peptides and has bactericidal activity based on membrane disruption. We investigated here the in vitro effectiveness of CSA-13 with a concentration of 100, 75, 50, and 25 mg/mL on proliferation of Acanthamoeba castellanii trophozoites and cysts and cytotoxic potential. CSA-13 was evaluated for its amoebicidal activity using an inverted light microscope at 1, 2, 4, 8, 12, and 24 h. For the determination of cytotoxicity of the CSA-13 on L929 cells, agar diffusion tests were performed. CSA-13 inhibited trophozoite growth in dose- and time-dependent ways. At 1 h, no viable trophozoites were observed in the presence of CSA-13 solution in a concentration 100 mg/mL in phosphate-buffered saline. Results of cytotoxicity experiments demonstrated that CSA-13 solution had mild toxicity at 100 mg/mL concentration on cells, whereas it had no toxicity at 75 mg/mL concentration. The findings of this experiment as in vitro ameboebicidal activity for Acanthamoeba suggest that CSA-13 has a potential to be used as a new agent in lens solutions to prevent Acanthamoeba growth and infections. [ABSTRACT FROM AUTHOR]

Background/Aims: Amoebic keratitis is difficult to treat with total efficacy in some patients because of cysts, which are less susceptible than trophozoites to the usual treatments. We investigated the in vitro effectiveness of methanolic extract of Salvia staminea and Salvia caespitosa against Acanthamoeba castellanii, as well as their cytotoxicity on corneal cells in vitro. Methods: Extracts were evaluated for their amoebicidal activities using an inverted light microscope. The effect of Savia species, with concentrations ranging between 1.0 and 32.0 mg/mL, on the proliferation of A. castellanii trophozoites and cysts were examined in vitro. For determining the cytotoxicity of Salvia species on corneal cells, agar diffusion tests were performed. Results: According to the results obtained from these tests, S. staminea showed remarkable amoebicidal effect on A. castellanii. In the case of the cytotoxic activity, methanolic extract of S. staminea showed no cytotoxicity on corneal cells with a concentration of 16 mg/mL. Conclusions: Methanolic extract of S. staminea could be considered a new natural agent against Acanthamoeba. However, further evaluation by in vivo testing is needed to confirm the efficiency of its biological effect. [ABSTRACT FROM AUTHOR]

Free-living protozoa of the genus Acanthamoeba can cause one of the most severe, potentially sight-threatening infections of the eye, the so-called A. keratitis. A. keratitis is difficult to treat because, under adverse conditions, the amoeba encyst and medical therapy is often less effective against cysts than against trophozoites. The aim of this study was to investigate evaluate the in vitro effect of the nonpolar subfraction of the methanol extract of garlic ( Allium sativum) on the growth of A. castellanii trophozoites and cysts and also its cytotoxicity on corneal cells in vitro. Extract was evaluated for its amoebicidal activity, using an inverted light microscope. The effect of the nonpolar extract with the concentrations, ranging from 0.78 to 62.5 mg/mL on the proliferation of A. castellanii trophozoites and cysts, were examined in vitro. For the determination of cytotoxicity of the extract on corneal cells, agar diffusion tests were performed. The present study demonstrates the in vitro effectiveness of the garlic against the A. castellanii growth curve. Evaluations revealed that garlic inhibits trophozoite growth in dose- and time-dependent ways. In the case of the cyctotoxic acitivities, it showed no cytotoxicity for the cornea cells in the concentration of 3.90 mg/mL. These findings indicate that nonpolar subfraction of the methanol extracts of garlic has amoebicidal, as well as its cysticidal, properties on Acanthamoeba trophozoites and cysts. Garlic alone, and in combination with other amoebicidal agents, may be used in clinical practices after further investigations. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate the in vitro effects of an ethanolic extract of propolis on the growth and adherence of Acanthamoeba castellanii trophozoites and cysts. Methods: The effect of propolis with concentrations of 8.0, 6.0, 5.0, 4.0, 3.0, and 2.0 mg/mL on the proliferation of A. castellanii trophozoites, and with a concentration of 62.25, 31.25, 15.62, 7.81, 3.90, 1.95, and 0.97 mg/mL on the proliferation of A. castellanii cysts, at 1, 3, 6, 12, 24, 48, and 72 h were examined in vitro. Results: After 1–72 h, incubation in concentrations between 2.0 and 6.0 mg/mL, its effect was amoebistatic; at concentrations of 8.0 mg/mL and higher, its effect was amoebicidal. After 48 h or longer incubation times at 15.62 mg/mL and at higher concentrations, the propolis extract was cysticidal. At concentrations of 1.97 mg/mL or lower, there was no observable effect at any time point. Conclusions: These findings indicate that ethanolic extract of propolis has amoebicidal, as well as cysticidal, properties for Acanthamoeba trophozoites and cysts. Propolis alone, or in combination with other amoebicidal agents, may be used in clinical practice after further investigations. [ABSTRACT FROM AUTHOR]