Amoebicidal effect of Allium cepa against Allovahlkampfia spelaea: A keratitis model.

Allovahlkampfia spelaea (A. spelaea) is a free-living amoeba, proved to cause Acanthamoeba-like keratitis with quite difficult treatment. This study aimed to evaluate the amoebicidal effect of Allium cepa (A. cepa) on A. spelaea trophozoites and cysts both in vitro and in vivo using Chinchilla rabbits as an experimental model of this type of keratitis. Chemical constituents of the aqueous extract of A. cepa were identified using Liquid Chromatography-mass Spectrometry (LC-MS). In vitro, A. cepa showed a significant inhibitory effect on trophozoites and cysts compared to the reference drug, chlorhexidine (CHX) as well as the non-treated control (P < 0.05) with statistically different effectiveness in terms of treatment durations and concentrations. No cytotoxic effect of A. cepa on corneal cell line was found even at high concentrations (32 mg/ml) using agar diffusion method. The in vivo results confirmed the efficacy of A. cepa where the extract enhanced keratitis healing with complete resolution of corneal ulcers in 80% of the infected animals by day 14 (post infection)pi compared to 70% recovery with CHX after 20 treatment days. The therapeutic effect was also approved at histological, immune-histochemical, and parasitological levels. Our findings support the potential use of A. cepa as an effective agent against A. spelaea keratitis.

Thymus vulgaris, Mentha piperita and Elettaria cardamomum against Trypanosoma evansi in vitro and in an animal model with new insights for the treatment of trypanosomosis.

Trypanosomosis is a worldwide disease that affects human and livestock populations with limited availability and high cost of trypanocides. The study aims to evaluate the possible in vitro and in vivo anti-trypanosomal activity of Thymus vulgaris (thyme), Mentha piperita (mint) and Elettaria cardamomum (cardamom) aqueous extracts against Trypanosoma evansi in experimentally infected rats using Intropar as a reference drug. The crude extracts of the selected plants were used in three concentrations (2500, 2000, and 1000 µg/ml). The in vitro trypanocidal activities were assessed regarding parasite motility, count, and infectivity. The in vivo susceptibility of T. evansi was evaluated by assessing the level of parasitemia in the experimental rats. The packed cell volume (PCV) was also monitored. Both the in vitro and in vivo experiments showed trypanocidal activity, of all the tested extracts, higher than that of Intropar. The in vitro trypanocidal effects were dose-dependent and represented by a significant reduction of the parasite count together with immobilizing effect within 3 hours incubation period, compared to the negative and positive controls (p< 0.05). The in vivo trypanocidal effects of the different concentrations of all the tested extracts were represented by the significantly lowered levels of parasitemia, compared to the negative control (NC) group with varying degrees; in a dose-dependent manner concerning the time. They exhibited also a significantly higher level in PCV recovery compared to the NC group (p < 0.05). This study initially confirmed the potent in vitro and in vivo trypanocidal effect of the three extracts, with a potentially promising future for the treatment of trypanosomosis.