Lipid-based nanoformulations of trifluralin analogs in the management of Leishmania infantum infections.

AIM: To improve the potential of trifluralin (TFL) in the management of Leishmania infantum infections through the synthesis of analogs (TFLA) and incorporation in nanoparticulate drug delivery systems (NanoDDS), liposomes and solid lipid nanoparticles, for selective targeting to leishmania infection sites. MATERIAL & METHODS: In vitro screening of 18 TFLA was performed by flow cytometry. NanoDDS were loaded with active TFLA and evaluated for antileishmanial efficacy in mice through determination of parasite burden in liver and spleen. RESULTS: The in vitro testing revealed the most active and nontoxic TFLAs, which were selected for the in vivo studies based on high incorporation in liposomes and lipid nanoparticles (>90%). Selected TFLA nanoformulations showed superior antileishmanial activity in mice (parasite burden >80%), over free TFLA and Glucantime. CONCLUSION: The modification of TFL structure to obtain active TFLA, together with their incorporation in NanoDDS, improved their in vivo performance against L. infantum infection.

Hemisynthetic trifluralin analogues incorporated in liposomes for the treatment of leishmanial infections.

Leishmaniasis, a vector-borne parasitic disease caused by Leishmania protozoa, is one of the most neglected tropical diseases in terms of drug discovery and development. Current treatment is based on a limited number of chemotherapeutic agents all of which present either/or resistance issues, severe toxicities and adverse reactions associated with extended treatment regimens, and high cost of therapy. Dinitroanilines are a new class of drugs with proven in vitro antileishmanial activity. In previous work a liposomal formulation of one dinitroaniline (TFL) was found to be active against Leishmania parasites in a murine model of visceral leishmaniasis (VL) and in the treatment of experimental canine leishmaniasis. In this study we have investigated the use of dinitroaniline analogues (TFL-A) associated to liposomes, as means to further improve TFL antileishmanial activity. The potential of the liposomal formulations was assessed in vitro against Leishmania infantum promastigotes and intracellular amastigotes and in vivo in a murine model of zoonotic VL. Free and liposomal TFL-A were active in vitro against Leishmania parasites, and they also exhibited reduced cytotoxicity and haemolytic activity. Treatment of infected mice with liposomal TFL-A reduced the amastigote loads in the spleen up to 97%, compared with the loads for untreated controls. These findings illustrate that chemical synthesis of new molecules associated with the use of Nano Drug Delivery Systems that naturally target the diseased organs could be a promising strategy for effective management of VL.

Application of random amplified polymorphic DNA (RAPD) to detect genotoxic effect of trifluralin on maize (Zea mays).

Trifluralin is a widely used dinitroaniline herbicide throughout the world. However, limited efforts have been made to study its genotoxic effects on different plants. The present study aimed to evaluate the herbicide's genotoxic potential on maize (Zea mays) by using the random amplified polymorphic DNA (RAPD) technique. For this purpose, maize seedlings were treated with aqueous solutions of trifluralin at concentrations ranging from 0.5 to 3 ppm for 7 days. In the RAPD analyses, 15 primers were used and 91 bands were obtained, with an average of 6.06 bands per primer in the control seedlings. After trifluralin treatment, significant changes were observed in RAPD profiles. These changes included loss of normal bands and appearance of new bands, in comparison to the control group, and they were dose dependent. In addition, root growth and total soluble protein level in trifluralin-treated seedlings were analyzed and compared for genomic template stability (GTS), which was performed for the qualitative measurement of changes in randomly amplified polymorphic DNA (RAPD) profiles. The results showed that GTS, root growth, and total soluble protein content of the seedlings gradually decreased with an increase in trifluralin concentration. These findings suggest that the RAPD technique is a useful biomarker assay to evaluate the genotoxic effects of herbicides on plants.

Combination and monotherapy of Leishmania major infection in BALB/c mice using plant extracts and herbicides.

BACKGROUND & OBJECTIVES: Leishmaniasis is a growing health problem in many parts of the world. Efforts to find new chemotherapeutics for leishmaniasis remain a priority. This study was carried out to determine the effect of combination and monotherapies using plant extracts and herbicides on Leishmania major infection in BALB/c mice. METHODS: The herbicides and saponin extract were purchased from Sigma. Roots of Plumbago capensis were collected from Karura forest, Nairobi, Kenya. Plant extractions were done in KEMRI at Center for Traditional Medicines and Drugs Research. RESULTS: Lesion sizes after infection of BALB/c mice were similar in all the experimental groups till the onset of therapeutic treatments (p >0.05). At 15 days post-treatment, significant differences (p < 0.05) were discerned in the lesion sizes of the BALB/c mice in all the mono- and combined-treated groups. However, the combined therapies caused total elimination of the parasites from the lesions and significantly reduced parasite burden in liver and spleen compared to the untreated controls at the end of the experiment. INTERPRETATION & CONCLUSION: The results of this study demonstrate that combination therapy using alternative administration of saponin, acriflavine, trifluralin and plumbagin is effective in treating L. major infection in mice. In this regard, an investigation into the efficacy of these combined therapies against other Leishmania strains should be explored further. Furthermore, studies with these combination therapies should be done on non-human primates such as the vervet monkey (Cercopithecus aethiops).

Trifluralin liposomal formulations active against Leishmania donovani infections.

The purpose of this study was to increase the therapeutic index of the antiparasitic drug, trifluralin (TFL), to allow its parenteral administration without the need of toxic solvents. This was achieved by incorporating TFL in liposomes with high loading capacity. These formulations were stable in freeze-dried form during at least one year and in frozen form during at least three months. Therapeutic activity, assessed on a visceral model of infection, showed that TFL liposomes reduced the number of parasites by up to one third or one half as compared to negative control and to free TFL, respectively.

Effect of 2,4-dicholorophenoxyacetic acid, trifluralin and triallate herbicides on immune function.

The commercial formulations of 3 commonly used herbicides (the amine salt of 2,4-dichlorophenoxyacetic acid, trifluralin and triallate) were evaluated for effects on immune function in male Fisher 344 rats. The herbicides were prepared in an olive oil vehicle and administered by oral gavage twice weekly for 28 d at the following doses: 10.0 mg 2,4-D/kg; 17.5 mg trifluralin/kg; 5.0 mg triallate/kg/treatment. Normal body weight and organ/body weight ratios indicated the rats tolerated the herbicide treatments without difficulty. Exposure to 2,4-D did not alter lymphocyte blastogenesis, 1 gm antibody production (anti-sheep red blood cell), lymphocyte cell surface marker expression or phagocytic function of peritoneal macrophages. Trifluralin acted as a weak mitogen, but impaired T-lymphocyte blastogenesis induced by phytohemagglutinin and concanavalin A. Other immunological measurements were unaffected by trifluralin exposure. Triallate exposure reduced peritoneal macrophage phagocytosis by 33%, showed weak mitogenic properties and impaired T-lymphocyte blastogenesis in the presence of phytohemagglutin. Triallate also increased the anti-sheep red blood cell response expressed/spleen by 43%, a phenomenon suggestive of a compensatory response to minimize the impact on overall immune function. The changes in lymphocyte or macrophage function due to the herbicide treatments were not associated with changes in lymphocyte cell surface antigen expression.

Oncogenicity study of trifluralin in B6C3F1 mice.

B6C3F1 mice were maintained for 24 months on diets containing 0, 563, 2250 or 4500 ppm trifluralin. These dietary concentrations corresponded to daily doses of approximately 70, 285 or 570 mg/kg body weight, respectively. The control group contained 120 mice/sex and treated groups consisted of 80 mice/sex. There were no treatment-related effects on the survival, appearance or behaviour of the mice. Survival at test termination was at least 67% in each group. Compared with controls, mean body weight was significantly reduced in a dose-related manner in mice of both sexes given the 2250 and 4500 ppm diets. At 21 months, the reduction in body weight was greater than or equal to 15 and greater than or equal to 30%, respectively. At study termination, dose-related decreases in erythrocytic and leucocytic values were also observed at dietary levels of 2250 and 4500 ppm. In clinical chemistry evaluations, blood urea nitrogen levels and alkaline phosphatase activity in mice of both sexes were significantly increased at trifluralin levels of 2250 and 4500 ppm. Blood urea nitrogen also showed a marginal increase in females given the low dose of trifluralin. Alanine aminotransferase activity was significantly increased in males at all treatment levels. Although there were a number of absolute and relative organ weight changes in all three treatment groups that were significantly different from the control values, the reduced relative kidney weights in males and the increased relative liver weights in both sexes at dietary levels of 2250 and 4500 ppm were the only changes that could be correlated with altered clinical chemistry values.(ABSTRACT TRUNCATED AT 250 WORDS)