In vitro leishmanicidal activity of two cholesterol derivatives.

We evaluated the leishmanicidal activity of commercially available 5α-cholest-7-en-3ß-ol [5α-chol], (+)-4-cholesten-3-one [(+)-4-chol] and the equimolar mixture of the two of them in promastigotes and amastigotes of two different strains of Leishmania mexicana (LCL) and (DCL). The leishmanicidal effectiveness of these sterols was determined by promastigote growth-kinetic experiments and promastigote viability using the propidium iodide staining procedure. The proliferation test was performed using the CFSE (5-Carboxyfluorescein N-succinimidyl ester) staining of parasites at different time points. To determine the leishmanicidal effectiveness of these sterols in amastigotes, we evaluated parasite killing inside of macrophages at different time points. The trypan blue exclusion test was used to determine cytotoxicity of sterols in uninfected macrophages. We included in all experiments a control group of parasites treated with 2% DMSO (Dimethyl Sulfoxide) and another one treated with the reference drug sodium stibogluconate (Sb). Our results showed that the equimolar mixture at 2000 times lower concentration presented similar leishmanicidal activity as Sb. This mixture was similarly effective at 100 times lower concentration than individual sterols tested separately indicating the existence of a synergistic effect against LCL and DCL parasites. The therapeutic index of the equimolar mixture was 10,000-16,000 times higher than the one recorded by Sb and was not cytotoxic to macrophages. Therefore, the equimolar mixture of 5α-Chol and (+)-4-chol may represent a potential alternative for the treatment of cutaneous leishmaniasis.

In vitro leishmanicidal and cytotoxic activities of the glycoalkaloids from Solanum lycocarpum (Solanaceae) fruits.

Leishmaniasis is an infection caused by a protozoan parasite of the genus Leishmania and is the second most prevalent parasitic protozoal disease after malaria in the world. We report the in vitro leishmanicidal activity on promastigote forms of Leishmania amazonensis and cytotoxicity, using LLCMK2 cells, of the glycoalkaloids from the fruits of Solanum lycocarpum, determined by colorimetric methods. The alkaloidic extract was obtained by acid-base extraction; solamargine and solasonine were isolated by silica-gel chromatography, followed by reversed-phase HPLC final purification. The alkaloidic extract, solamargine, solasonine, as well as the equimolar mixture of the glycoalkaloids solamargine and solasonine displayed leishmanicidal activity against promastigote forms of L. amazonensis, whereas the aglycone solasodine was inactive. After 24 and 72 h of incubation, most of the samples showed lower cytotoxicities (IC50 6.5 to 124 µM) as compared to leishmanicidal activity (IC50 1.1 to 23.6 µM). The equimolar mixture solamargine/solasonine was the most active with an IC50 value of 1.1 µM, after 72 h. Likewise, solamargine was the most active after 24 h with an IC50 value of 14.4 µM, both in comparison with the positive control amphotericin B.

Anti-Leishmania activity of the Mayan medicinal plant Thouinia paucidentata Radlk extracts.

Mexico's Yucatan Peninsula is an endemic area of cutaneous leishmaniasis, locally known as the chiclero's ulcer, and Mayan traditional medicine which refers to the use of Thouinia paucidentata Radlk, known as k'an chuunup. Aqueous and organic leaves extracts were evaluated against promastigotes and amastigotes of Leishmania mexicana. Toxicity tests of extracts were performed using Vero and J774A.1 macrophage cell lines. The composition of the most active extracts was analysed by GC-MS. The n-hexane and ethyl acetate extracts showed potent anti-Leishmania activity against the promastigote form, and remarkably, n-hexane extract exhibited potent activity against the amastigote form. Both extracts showed low toxicity on Vero both not on J774A.1 cells. Analysis of both bioactive extracts identified as more abundant compounds, germacrene D-4-ol and thunbergen in n-hexane, and thunbergol in ethyl acetate extracts. Our study presents T. paucidentata as anti-Leishmania phytomedicine supporting its medicinal use and contributes to the understanding of its phytochemical composition.

Leishmanicidal activity of two naphthoquinones against Leishmania donovani.

Here we studied ability of two naphthoquinones to inhibit Leishmania growth (2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone (TR 001) and 2,3-dibromo-1,4-naphthoquinone (TR 002). TR 001 was more efficient than TR 002 in inducing killing of promastigotes and intracellular amastigotes. These values compare well to those obtained with the standard first-line antileishmanial agent sodium stibogluconate (SSG). TR 001 also induced significantly more nitric oxide (NO) production than TR 002 or SSG. Taken together, these data show that TR 001 and TR 002 could be promising new drugs for treatment of visceral leishmaniasis.

Detection of pathogenic bacteria in skin lesions of patients with chiclero's ulcer. Reluctant response to antimonial treatment.

We investigated the bacterial flora present in skin lesions of patients with chiclero's ulcer from the Yucatan peninsula of Mexico using conventional culture methods (11 patients), and an immunocolorimetric detection of pathogenic Streptococcus pyogenes (15 patients). Prevalence of bacteria isolated by culture methods was 90.9% (10/11). We cultured, from chiclero's ulcers (60%), pathogenic bacterial such as Staphylococcus aureus (20%), S. pyogenes (1.6%), Pseudomonas aeruginosa (1.6%), Morganella morganii (1.6%), and opportunist pathogenic bacteria such as Klebsiella spp. (20.0%), Enterobacter spp. (20%), and Enterococcus spp. (20%). We also cultured coagulase-negative staphylococci in 40% (4/10) of the remaining patients. Micrococcus spp. and coagulase-negative staphylococci constituted the bacterial genuses more frequently isolated in the normal skin of patients with chiclero's ulcer and healthy individuals used as controls. We also undertook another study to find out the presence of S. pyogenes by an immunocolorimetric assay. This study indicated that 60% (9/15) of the ulcerated lesions, but not normal controls, were contaminated with S. pyogenes. Importantly, individuals with purulent secretion and holding concomitant infections with S. pyogenes, S. aureus, P. aeruginosa, M. morganii, and E. durans took longer to heal Leishmania (L.) mexicana infections treated with antimonial drugs. Our results suggest the need to eliminate bacterial purulent infections, by antibiotic treatment, before starting antimonial administration to patients with chiclero's ulcer.

Detection of pathogenic bacteria in skin lesions of patients with chiclero's ulcer: reluctant response to antimonial treatment

We investigated the bacterial flora present in skin lesions of patients with chiclero's ulcer from the Yucatan peninsula of Mexico using conventional culture methods (11 patients), and an immunocolorimetric detection of pathogenic Streptococcus pyogenes (15 patients). Prevalence of bacteria isolated by culture methods was 90.9 percent (10/11). We cultured, from chiclero's ulcers (60 percent), pathogenic bacterial such as Staphylococcus aureus (20 percent), S. pyogenes (1.6 percent), Pseudomonas aeruginosa (1.6 percent), Morganella morganii (1.6 percent), and opportunist pathogenic bacteria such as Klebsiella spp. (20.0 percent), Enterobacter spp. (20 percent), and Enterococcus spp. (20 percent). We also cultured coagulase-negative staphylococci in 40 percent (4/10) of the remaining patients. Micrococcus spp. and coagulase-negative staphylococci constituted the bacterial genuses more frequently isolated in the normal skin of patients with chiclero's ulcer and healthy individuals used as controls. We also undertook another study to find out the presence of S. pyogenes by an immunocolorimetric assay. This study indicated that 60 percent (9/15) of the ulcerated lesions, but not normal controls, were contaminated with S. pyogenes. Importantly, individuals with purulent secretion and holding concomitant infections with S. pyogenes, S. aureus, P. aeruginosa, M. morganii, and E. durans took longer to heal Leishmania (L.) mexicana infections treated with antimonial drugs. Our results suggest the need to eliminate bacterial purulent infections, by antibiotic treatment, before starting antimonial administration to patients with chiclero's ulcer.

Calidad sanitaria del agua para consumo humano en una comunidad rural de Mexico / Sanitary quality of water for human consumption in rural community of Mexico

Con el propósito de conocer la calidad sanitaria del agua consumida por la población de Bécal, comunidad rural de México, se investigó la presencia de organismos mesofílicos aerobios, coliformes totales y coliformes fecales en diferentes puntos del sistema de distribución del agua, así como en pozos y depósitos de agua de origen pluvial intradomiciliarios. Los resultados sugieren la existencia de factores propios de la región que condicionan la exposición del agua a la contaminación por materia orgánica en las diferentes unidades estudiadas. Se demuestra la necesidad de realizar un cuidadoso control sanitario del agua destinada al consumo humano a través de la instrumentación de programas que garanticen una vigilancia sistemática de las fuentes de abastecimiento y distribución, así como de implementar programas de educación a la comunidad sobre medidas generales de higiene y de control de las enfermedades gastrointestinales.