In vitro amoebicidal activity of four Peucedanum species on Acanthamoeba castellanii cysts and trophozoites (original) (raw)
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Parasitology Research, 2011
Amoebic keratitis is difficult to treat without total efficacy in some patients because of cysts, which are less susceptible than trophozoites to the usual treatments. The aim of this study is to evaluate the in vitro amoebicidal activity of the methanolic extracts of Satureja cuneifolia and Melissa officinalis. In the presence of methanolic extracts (ranging from 1.0 to 32.0 mg/ml), numbers of the viable Acanthamoe castellanii trophozoites and cysts were decreased during the experimental process. Both extracts showed a time-and dose-dependent amoebicidal action on the trophozoites and cysts. Among the extracts tested, S. cuneifolia showed the strongest amoebicidal effect on the trophozoites and cysts. In the presence of 32 mg/ml extract, no viable trophozoites were observed within 24 h. At the same concentration value, the extract was found effective against the cysts at a rate of 46.3% within 72 h of the experimental process. At 16 mg/ml extract concentration, no viable trophozoites were also observed in the 24th hour of the experiment. At the end of the experimental process, 34.7% of the cysts were killed by the extract. M. officinalis showed moderate amoebicidal effect. At the concentration of 32 mg/ml, 44.3% and 30.0% of the trophozoites and cysts were killed by the extract, respectively. Results obtained from these concentration values were found statistically different in terms of their actions both on trophozoites and cysts (p<0.05).
Parasitology Research, 2011
The aim of this study is to evaluate the in vitro amoebicidal activity of the aqueous extracts of Pastinaca armenea and Inula oculus-christi from Turkey. In the presence of aqueous extracts (ranging from 1.0 to 32.0 mg/ml), numbers of the viable Acanthamoeba castellanii trophozoites and cysts were decreased during the experimental process. Both extracts showed a time- and dose-dependent amoebicidal action on the trophozoites and cysts. Among the extracts tested, I. oculus showed the strongest amoebicidal effect on the trophozoites and cysts. In the presence of 32.00 mg/ml extract solution in the media, no viable trophozoites were determined from the time of 24 h. Moreover, in the presence of 16.00 mg/ml I. oculus-christi extract, no viable trophozoites were detected in 72 h of the experiment. Effectiveness of I. oculus-christi extract was found moderate against the cysts. In the presence of 32.00 mg/ml extract, only 25.3% of the total cysts were killed effectively. In the case of P. armenea, 40.3% and 23.0% of the trophozoites and cysts were killed in the presence of 32.00 mg/ml extract at the end of the experimental process (72 h), respectively.
Parasitology Research, 2011
The aim of this study is to evaluate the in vitro amoebicidal activity of the aqueous extracts of Pastinaca armenea and Inula oculus-christi from Turkey. In the presence of aqueous extracts (ranging from 1.0 to 32.0 mg/ml), numbers of the viable Acanthamoeba castellanii trophozoites and cysts were decreased during the experimental process. Both extracts showed a time- and dose-dependent amoebicidal action on the trophozoites and cysts. Among the extracts tested, I. oculus showed the strongest amoebicidal effect on the trophozoites and cysts. In the presence of 32.00 mg/ml extract solution in the media, no viable trophozoites were determined from the time of 24 h. Moreover, in the presence of 16.00 mg/ml I. oculus-christi extract, no viable trophozoites were detected in 72 h of the experiment. Effectiveness of I. oculus-christi extract was found moderate against the cysts. In the presence of 32.00 mg/ml extract, only 25.3% of the total cysts were killed effectively. In the case of P. armenea, 40.3% and 23.0% of the trophozoites and cysts were killed in the presence of 32.00 mg/ml extract at the end of the experimental process (72 h), respectively.
Parasitology Research, 2011
Amoebic keratitis is difficult to treat without total efficacy in some patients because of cysts, which are less susceptible than trophozoites to the usual treatments. The aim of this study is to evaluate the in vitro amoebicidal activity of the methanolic extracts of Teucrium polium and Teucrium chamaedrys. In the presence of methanolic extracts (ranging from 1.0 to 32.0 mg/ml), numbers of the viable Acanthamoeba castellani trophozoites and cysts were decreased during the experimental process. Both extracts showed time-and dose-dependent amoebicidal action on the trophozoites and cysts. Among the extracts tested, T. chamaedrys showed the strongest amoebicidal effect on the trophozoites. In the presence of 16 mg/ml or above extract concentrations, no viable trophozoites were observed within 48 h. In the case of T. polium, no viable trophozoites were observed within 48 h at 32 mg/ml concentration. As expected, cysts were found more resistant to the extracts than the trophozoites.
Experimental Parasitology, 2012
In some patients, complete treatment of amoebic keratitis is difficult because of the resistance of cysts to therapeutic agents. The aim of this study was to evaluate the in vitro amoebicidal activity of methanolic extracts of Origanum syriacum and Origanum laevigatum. In the presence of methanolic extracts (ranging from 1.0 to 32.0 mg/ml), numbers of the viable Acanthamoeba castellanii trophozoites and cysts were decreased. Both extracts showed a time and dose dependent amoebicidal action on the trophozoites and cysts. Of the extracts tested, O. syriacum showed the stronger amoebicidal effect on the trophozoites and cysts. In the presence of 32 mg/ml extract, no viable trophozoites were observed within third hour. The extract was also found effective against the cysts within 24th hour. In the case of O. laevigatum, no viable trophozoites were observed within 72nd hour at the concentrations of 16 and 32 mg/ml. As expected, cysts were found more resistant to the extracts than the trophozoites.
Translational Vision Science & Technology
The purpose of this study was to analyze the concentration-dependent effects of biguanides (polyhexamethylene biguanide [PHMB], chlorhexidine [CH]); diamidines (hexamidine-diisethionate [HD], propamidine-isethionate [PD], dibromopropamidinediisethionate [DD]); natamycin (NM); miltefosine (MF); povidone iodine (PVPI), and chlorin e6 PDT on Acanthamoeba trophozoites and cysts, in vitro. Methods: Strain 1BU was cultured in peptone-yeast extract-glucose medium. Trophozoites or cysts were cultured in PYG medium containing each agent at 100%, 50%, and 25% of maximum concentration for 2 hours. The percentage of dead trophozoites was determined using a non-radioactive cytotoxicity assay and trypan blue staining. Treated cysts were also maintained on non-nutrient agar Escherichia coli (E. coli) plates and observed for 3 weeks. Results: All tested drugs displayed significant cytotoxic effects on 1BU cells based on the biochemical and staining-based viability assays tested. On non-nutrient agar E. coli plates, neither trophozoites nor freshly formed cysts were observed after PHMB, PD, NM, and PVPI treatment, respectively, within 3 weeks. However, CH-, HD-, DD-, and MFtreated cysts could excyst, multiply, and encyst again. Conclusions: The off-label drugs PHMB, PD, NM, and PVPI are under in vitro conditions more effective against strain 1BU than CH, HD, DD, and MF. Our findings also suggest that the non-nutrient agar E. coli plate assay should be considered as method of choice for the in vitro analysis of the treatment efficacy of anti-amoebic agents. Translational Relevance: Ophthalmologists may optimize the treatment regime against Acanthamoeba keratitis by pre-testing the in vitro susceptibilities of the Acanthamoeba strain against drugs of interest with the non-nutrient E. coli agar plate assay.
Journal of the Egyptian Society of Parasitology, 2017
Acanthamoeba is an opportunistic pathogen causing keratitis and fatal encephalitis. Early diagnosis, followed by intense treatment using a drugs mixture is a necessity for effective therapy. Many natural compounds have proved lethal effects, yet the search for original natural amebicidal agents is still of current concern. This study investigated the acanthamoebicidal effect of A. hypogaea L. pericarp; total ethanol extract and its successive fractions, n-hexane, dichloro-methane, ethyl acetate, and methanol as well as resveratrol. Acanthamoebae were isolated and cultivated on E. coli seeded nonnutrient agar, genotyped, and the in vitro acanthamoebicidal potentials of different concentrations of A. hypogaea L. pericarp; total extract ethanol and its successive fractions and resveratrol compound was investgated on cysts of A. astronyxis T7 genotype. The results showed variable degrees of lethal potentials were obtained by all examined A. hypogaea L. pericarp ethanol extract and its successive fractions, with the highest mean of non-viable cysts on the first and the second days of the study by total ethanol extract followed by the methanol fraction. On the third day of the study n-hexane and ethyl acetate gave the highest mean of non-viable cysts. Resveratrol showed the lowest mean of non-viable cysts count all through the study duration. Significantly higher difference was observed between all examined A. hypogaea L. pericarp extract and fractions and chlorohexidine, except for resveratrol compound the difference was found to be non-significant.
2012
Acanthamoeba castellanii causes amoebic keratitis which is a painful sight-threatening disease of the eyes. Its eradication is difficult because the amoebas encyst making it highly resistant to anti-amoebic drugs, but several medicinal plants have proven to be more effective than the usual therapy. This study aimed to evaluate the in vitro amoebicidal activity of ethanol extracts of Arachis hypogaea L. (peanut), Curcuma longa L. (turmeric), and Pancratium maritimum L. (sea daffodil) on A. castellanii cysts. Acanthamoeba were isolated from keratitic patients, cultivated on 1.5% non-nutrient agar, and then incubated with different concentrations of plant extracts which were further evaluated for their cysticidal activity. The results showed that all extracts had significant inhibitory effect on the multiplication of Acanthamoeba cysts as compared to the drug control (chlorhexidine) and non-treated control, and the inhibition was time and dose dependent. The ethanol extract of A. hypogaea had a remarkable cysticidal effect with minimal inhibitory concentration (MIC) of 100 mg/ml in all incubation periods, while the concentrations of 10 and 1 mg/ml were able to completely inhibit growth after 48 and 72 h, respectively. The concentrations 0.1 and 0.01 mg/ml failed to completely inhibit the cyst growth, but showed growth reduction by 64.4–82.6% in all incubation periods. C. longa had a MIC of 1 g and 100 mg/ml after 48 and 72 h, respectively, while the concentrations 10, 1, and 0.1 mg/ml caused growth reduction by 60–90.3% in all incubation periods. P. maritimum had a MIC of 200 mg/ml after 72 h, while the 20-, 2-, 0.2-, and 0.02-mg/ml concentrations showed growth reduction by 34–94.3% in all incubation periods. All extracts seemed to be more effective than chlorhexidine which caused only growth reduction by 55.3– 80.2% in all incubation periods and failed to completely inhibit the cyst growth. In conclusion, ethanol extracts of A. hypogaea, C. longa, and P. maritimum could be considered a new natural agent against the Acanthamoeba cyst.
Journal of Applied Microbiology, 1997
1997. A non-radioactive method was used to investigate the uptake by Acanthamoeba castellanii of chlorhexidine diacetate (CHA) and polyhexamethylene biguanide (PHMB). Based on the Giles et al. (1974) hypothesis, the uptake of CHA by trophozoites appeared to be of the L3 pattern whereas that of cysts was C2. Unlike CHA, trophozoites took u p PHMB with an L2 pattern at low concentrations followed by a C-type pattern at higher concentrations, the uptake by cysts was found to be of the C2 pattern with a plateau effect at high concentrations. A diphasic leakage effect was found in trophozoites whereas a relatively low peak of maximal leakage occurred from cysts treated with high biocide concentrations. T h e amount of pentose release depended on the formulation ingredients. No correlation between pentose leakage and trophozoicidal or cysticidal activity was found.
The lethal effects of biguanides on cysts and trophozoites of Acanthamoeba castellanii
The Journal of applied bacteriology, 1996
The effects of a range of biocides on trophozoite and encysted forms of Acanthamoeba castellanii were investigated. Viable acanthamoebae were enumerated by a plaque assay technique. The cyst form of Acanthamoeba castellanii was more resistant to all biocides tested than the trophozoite form. Of the biocides tested, chlorhexidine diacetate (CHA) and polyhexamethylene biguanide (PHMB) were the most effective. Their lethal effects were time- and concentration-dependent. CHA was very effective when formulated in 0.1% EDTA combined with Tris buffer pH 7.8 whereas PHMB activity was reduced by 0.1% EDTA. Three per cent dimethylsulphoxide (DMSO) enhanced the activity of CHA but not of PHMB.