Effect of aqueous extract of Eucalyptus Microtheca on Acanthamoeba genotype T5, an in vitro study.

Background: Acanthamoeba is a resilient protozoan that causes serious diseases such as Acanthamoeba Keratitis (AK). Due to the ineffectiveness of many drugs against this parasite, plant extracts provide a promising alternative in the treatment process. This study aimed to assess the effectiveness of the aqueous extract of Eucalyptus microtheca against Acanthamoeba trophozoites and cysts in vitro.

Methods: In the current experimental study, Acanthamoeba isolate was cultured in a non-nutritive agar (NNA) medium. Aqueous extracts of Eucalyptus microtheca were prepared at concentrations of 10, 20, 40, and 80 mg/ mL, with exposure times of 30, 60, 90, and 120 min for trophozoites and 24, 48, and 72 h for cysts. Chlorhexidine (0.02%) and PBS served as positive and negative controls, respectively. Viability was assessed using 1% eosin dye.

Results: Our study revealed that the aqueous extract of Eucalyptus microtheca significantly reduced the number of both trophozoites and cysts. At 80 mg/ mL, the extract completely eliminated cysts (100%) after 24 h and reduced trophozoites by 99.33% within 120 min.

Conclusion: This study indicates that Eucalyptus microtheca aqueous extract possesses significant anti-Acanthamoeba properties, with effects strongly associated with concentration and exposure time (p < 0.001).