Effect of Hypericum thymbrifolium BOISS. ET NOE, Hypericum scabrum L. and Eryngium creticum LAM. plant extracts on Leishmania major, Leishmania tropica and Leishmania infantum/donovani strains and their cytotoxic potential.

Leishmaniasis causes significant morbidity and mortality worldwide. In our country, there has been a significant increase in the number of cases of leishmaniasis in the last decade. In our study, the effects of Hypericum thymbrifolium, Hypericum scabrum and Eryngium creticum plant extracts were tested on Leishmania major, Leishmania tropica and Leishmania infantum/donovani, which were clinically resistant by not responding to Glucantime® therapy. Cytotoxicity of these extracts were evaluated by XTT method in the human fibroblast cell line. Possible active ingredients were detected by GC-MS analysis from plant extracts. Glucantime® resistance was detected at concentrations of 50 µg/mL and lower in 4 of the 7 strains tested. No living leishmania parasites were found in leishmania strains treated with plant extracts at concentrations of 100 µg/mL or higher. The concentrations of plant extracts included in the study on the WI-38 human fibroblast cell line were not cytotoxic. According to the GC-MS analysis, several active substances with biological activities and anti-parasitic effects, such as Thiophene, Germacrene-D, trans-Geranylgeraniol, Pyridine, and Maleimides, were identified. Based on the findings of the study, it is believed that these identified active substances when supported by in-vivo studies, will pave the way for future research and have the potential to be developed as anti-leishmania drugs.

In vitro antileishmanial activity of Adana propolis samples on Leishmania tropica: a preliminary study.

Propolis (bee glue) is a natural resinous hive product, collected from various plant sources. It has attracted much attention as a useful substance applied in medicine due to its pharmacological activities. It was aimed to investigate the in vitro effects of an ethanolic extract of Adana propolis samples on the growth of Leishmania tropica. Parasite cells were treated with five concentrations (25, 50, 100, 50, 500, and 750 microg/ml) of the propolis. The number of promastigotes in each concentration was calculated using a hemocytometer slide at 24, 48, and 72 h after being harvested. In the experiments, it was determined that the concentrations up to 100 mug/ml of the propolis did not exhibit antileishmanial activity against the parasites cells. At these concentrations, there was no changes in terms of morphologically. In addition, there was no statistically significant difference in terms of cell count between control and these three groups (p > 0.05). However, in culture media containing the propolis samples at 250, 500, and 750-microg/ml concentrations, statistically significant differences in cell counts were observed, as compared to the control group (p < 0.05). Our results demonstrate that ethanolic extracts of Adana propolis samples reduce the proliferation of L. tropica parasites significantly.

Multi-site DNA polymorphism analyses of Leishmania isolates define their genotypes predicting clinical epidemiology of leishmaniasis in a specific region.

Leishmania isolates from 57 cases of human cutaneous (CL), human visceral (VL), and canine visceral (CVL) leishmaniasis in Turkey were grouped by multi-site DNA polymorphism analyses into five genotypes. The initial grouping was based on DNA heterogeneity of the faster-evolving mitochondrion (kinetoplast) minicircles and the intergenic regions of two nuclear repetitive genes. Taxonomic affiliation and phylogenetic relationships of the five genotypes were inferred by comparing them with reference species for sequence heterogeneity in a approximately 1.4 kb conserved single-copy gene, encoding N-acetylglucosamine-1-phosphate transferase (NAGT). Alignment of the available sequences revealed no gap, but up to 7% scattered base substitutions, suggesting that this functionally important gene is a suitable marker. Three genotypes are completely identical to the NAGTs of the reference species, identifying them as L. infantum, L. tropica. and L. major, respectively. The remaining two are recognized as L. major NAGT variants with one and four base substitutions, respectively. As expected, Maximum Likelihood analysis of the NAGT sequences separates them into three clades, corresponding to the three species. The majority of the isolates obtained are L. infantum and L. tropica, which have been known to cause infantile VL and anthroponotic CL in western and southeastern Turkey, respectively. Unexpected is the finding of Leishmania major variants and their dispersal, possibly as previously unrecognized clinico-epidemiologic entities of CL and VL.