چکیده (انگلیسی):

Objective: To examine the acanthamoebicidal effects of ethyl acetate, aqueous and
butanol fractions of dried flower buds of Lonicera japonica (L. japonica) Thunb. (Flos
Lonicerae) in vitro.
Methods: Acanthamoeba triangularis isolates were obtained from environmental water
samples and identified by PCR. They were exposed to ethyl acetate, water and butanol
fractions of L. japonica Thunb. at concentrations ranging from 0.5 mg/mL to 1.5 mg/mL.
The extracts were evaluated for growth inhibition at 24, 48 and 72 h, respectively.
Chlorogenic acid at a concentration of 1 mg/mL was examined for inhibition of
encystment.
Results: Ethyl acetate fraction at a concentration of 1.5 mg/mL evoked a significant
reduction of trophozoite viability by 48.9% after 24 h, 49.2% after 48 h and 33.7% after
72 h chlorogenic acid, the major active constituent of L. japonica Thunb. at the concentration
of 1 mg/mL reduced the cysts/trophozoite ratio by 100% after 24 h, 84.0%
after 48 h and 72.3% after 72 h. This phenolic compound at concentration of 1 mg/mL
concurrent with 0.6% hydrogen peroxide inhibited hydrogen peroxide-induced encystment
by 92.8% at 72 h.
Conclusions: Results obtained from this study show that ethyl acetate fraction at
1.5 mg/mL is the most potent fraction of L. japonica Thunb. and its major constituent
chlorogenic acid showed the remarkable inhibition of encystment at a concentration of
1 mg/mL.