A New Strategy for Enhancing Acanthamoebicidal Activity with Synthesis of Nanoflower of Laurocerausus officinalis Roemer (Cherry laurel) Fruit Extracts

Abstract

Pathogenic Acanthamoeba species often cause infection known as Acanthamoeba keratitis among people who use contact lenses. It is a type of infection that can result in corneal ulceration, visual loss or even blindness, if not treated. There are various therapeutic options available in the treatment of Acanthamoeba infections but they are usually tough treatments with limited efficacy. For instance, hydrogen peroxide (H2O2) is a commonly used contact lens disinfectant which is effective against Acanthamoeba but it is toxic to the cornea. For these reasons, new and more efficacious treatment options are required for Acanthamoeba infections. In this context, plants are considered natural resources for the discovery of new drugs. Laurocerasus officinalis Roem. (cherry laurel) (Rosaceae) grows in Black Sea region; and it is known as "Taflan", "Laz kirazi" or "Karayemis". Local people are using the seeds against diabetes, while the fruits are consuming as food, and used fordiuretic and passing kidney stones. It has also been reported that the seeds of the cherry laurel are used as an antiparasitic agent in this area. The aim of the study was to confirm the traditionally use of antiparasitic activity of this fruit and to increase the potential effect by means of organic-inorganic hybrid synthesis. Total phenol contents of methanol extracts prepared from endocarp, mesocarp and seeds of the fruit were calculated. The effects of methanol extracts and nano flower (NFs) plants synthesized from these extracts on the proliferation of Acanthamoeba castellanii were investigated. Thus, for the first time, novel organic-inorganic nanobio-antiparasitic agents called NFs were produced from cherry laurel and the increase in the amoebicidal activity of the NFs was elucidated. The characterization of NFs were determined with Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrometer (FT-IR) and Energy-Dispersive X-ray (EDX) techniques. In addition, the catalytic activity of the fruit extracts and the NFs were measured against guaiacol in the presence of H2O2. The viability testing of A. castellaniicysts used for amoebicidal activity was performed using 4% trypan blue. Methanol extracts and nano-flowers were prepared at concentrations of 32, 16, 8, 4, 2 and 1 mg/ml in 0.9% saline and distributed 200 pl each in tubes and incubated in the room temperature with the addition of 200 pl of 98% viable A.castellani parasites. The results were evaluated using the SPSS V.22.0 program and it was determined that there was a significant increase in the amoebicidal activity of NFs compared with the other extracts according to variance analysis (p <= 0.05). In the study, it was determined that samples killed parasites or reduced parasite proliferation at certain times. As a result, NFs synthesized from fruit extracts were demonstrated about three times more effective than the non hybrid extracts for amoebicidal activity. This situation can be explained as high proliferative effect of a new nano-bio-antiparasitic agent known as nanoflower against A.castellanii