Hector Nakayama

Efficacy of Orally Administered 2-Substituted Quinolines in Experimental Murine Cutaneous and Visceral Leishmaniases

ABSTRACT We report in this study the in vivo efficacy of nine 2-substituted quinolines on the Leishmania amazonensis cutaneous infection murine model and on the Leishmania infantum and Leishmania donovani visceral infection murine models. In the case of the L. amazonensis model, quinolines were administered orally at 25 mg/kg twice daily for 15 days. Quinolines 1, 2, 3, and 7 reduced by 80 to 90% the parasite burdens in the lesion, whereas N-methylglucamine antimoniate (Glucantime), administered by subcutaneous injections at 100 mg [28 mg Sb(V)] per kg of body weight daily, reduced the parasite burdens by 98%. In visceral leishmaniasis due to L. infantum, mice treated orally at 25 mg/kg daily for 10 days with quinolines 1, 4, 5, and 6 showed a significant reduction of parasite burdens in the liver and spleen. These quinolines were significantly more effective than meglumine antimoniate to reduce the parasite burden in both the liver and spleen. Also, the oral in vivo activity of three quinolines (quinolines 4, 5, and 2-n-propylquinoline) were determined against L. donovani (LV 9) at 12.5 and 25 mg/kg for 10 days. Their activity was compared with that of miltefosine at 7.5 mg/kg. Miltefosine, 2-n-propylquinoline, and quinoline 5 at 12.5 mg/kg significantly reduced the parasite burdens in the liver by 72, 66, and 61%, respectively. From the present study, quinoline 5 is the most promising compound against both cutaneous and visceral leishmaniasis. The double antileishmanial and antiviral activities of these compounds suggest that this series could be a potential treatment for coinfection of Leishmania-human immunodeficiency virus.

Leishmanicidal activity of two canthin-6-one alkaloids, two major constituents of Zanthoxylum chiloperone var. angustifolium

The crude alkaloidal extract of Zanthoxylum chiloperone stem bark exhibited in vitro activity against various strains of Leishmania ssp. at 100 microg/ml. Two active major constituents were isolated and identified as canthin-6-one and 5-methoxycanthin-6-one. The effect of these compounds was also tested in an in vivo assay using BALB/c mice infected with Leishmania amazonensis. The mice were treated for 5 weeks postinfection with these alkaloids by oral (14 days) or intralesional route (4 days) at 10 mg/kg daily. The reference drug, N-methylglucamine antimonate was administered by subcutaneous injections at 100 mg/kg for 10 days. Intralesional administration of canthin-6-one reduced the parasite burden but not significantly when it was compared with the untreated group, while the reference drug reduced by 91% the parasite loads in the lesion.

Activity of a hydroxybibenzyl bryophyte constituent against Leishmania spp. and Trypanosoma cruzi: in silico, in vitro and in vivo activity studies.

The synthesis and potent antiprotozoal activity of 14-hydroxylunularin, a natural hydroxybibenzyl bryophyte constituent is reported. 14-hydroxylunularin was highly active in vitro assays against culture and intracellular forms of Leishmania spp. and Trypanosoma. cruzi, in absence of cytotoxicity against mammalian cells. Preliminary structure-activity relationship studies showed that the reported bioactivity depends on hybridization at the carbon-carbon bridge, position and number of free hydroxy group on the aromatic rings. The reported results were also in agreement with the in silico prediction using Non-Stochastic Quadratic Fingerprints-based algorithms. The same compound also showed antiprotozoal activity in Leishmania spp. infected mice by oral and subcutaneous administration routes, with an optimal treatment of a daily subcutaneous administration of 10 mg/kg of body weight for 15 days. This study suggested that 14-hydroxylunularin may be chosen as a new candidate in the development of leishmanicidal therapy.

Leishmanicidal and trypanocidal activity of extracts and secondary metabolites from basidiomycetes

Seventeen extracts and seven secondary metabolites isolated from basidiomycetes were tested in medium culture against promastigote forms of Leishmania spp. and bloodstream forms of Trypanosoma cruzi. Extracts from the culture filtrate or mycelium were generally inactive against the parasites except the Zucoagaricus genus mycelium extract which reduced by 47% the number of bloodstream forms. Striatin A, striatin B and podoscyphic acid exhibited in vitro activity at 10, 5 and 100 μg/mL, respectively. One compound showed activity against bloodstream forms of T. cruzi, the sesquiterpenoid naematolin, lysing the parasites by 79%. BALB/c mice infected with L. amazonensis were treated 3 weeks post‐infection with striatin A and striatin B by subcutaneous route for 15 days at 10 mg/kg daily. The reference drug, N‐methylglucamine antimonate, administered by subcutaneous injections at 28 mg Sbv/kg/day for 15 days reduced the parasite burden by 71.2% (p <0.05). Subcutaneous administration of straitin A at 10 mg/kg produced a weak decrease of the parasite burdens in the footpad by 17.6%. The treatment with striatin B had no effect and showed higher toxicity than striatin A.

Studies on quinones. Part 34: The reaction of styrene with activated 1,4-benzoquinones: access to potential antiprotozoal pyranobenzoquinones ☆

Abstract Styrene reacts with highly electrophilic monosubstituted 1,4-benzoquinones to provide pyranobenzoquinone and phenanthrene derivatives, depending on the nature of the quinone substituent. The participation of transient Diels–Alder adduct intermediates in these reactions and their thermal-induced rearrangements are discussed. The in vitro antiparasital effects of the pyranobenzoquinones against Trypanosoma cruzi and Leishmania spp. are reported.

In vitro and in vivo leishmanicidal studies of Peperomia galioides (Piperaceae)

Petroleum ether and methylene chloride extracts of Peperomia galioides and three prenylated diphenols, grifolic acid, grifolin and piperogalin exhibited in vitro antileishmanial activity. During the course of infection of BALB/c mice with Leishmania amazonensis, the treatments with each of these compounds did not influence the progression of the disease.

The effect of bisbenzylisoquinoline alkaloids on Trypanosoma cruzi infections in mice

Five bisbenzylisoquinoline (BBI) alkaloids, curine, cycleanine, isotet:andrine, limacine and pheanthine were tested for trypanocidal activity in C 3H He mice infected with Y or CL strain of Trypanosoma cruzi. The activity was compared with the baseline drug, benznidazole. Oral treatment was more effective with curine at 10 mg/kg or with cycleanine at 2 mg/kg daily for 10 days in mice infected with Y or CL strain. In these groups, the parasitemias were negative after 5-7 weeks after inoculation and mortality time 50 (MT(50)) was significantly higher than untreated mice. Benznidazole was effective in mice infected with CL strain but not in mice infected with Y strain. The other BBI showed a relative efficacy against both strains. The effect of BBI alkaloids could be due to a blocking of the Ca2+ channel for the regulation of T. cruzi infectivity to invade host cells or their selective immunosuppressive properties.

SYNTHESIS OF 4-ALKYLAMINO-6-CHLOROQUINOLINES AS POTENTIAL TRYPANOCIDAL AGENTS

A simple synthesis of 4-alkylamino-6-chloroquinolines 5-9 from 5,8-dimethoxy-6-chloro-4(lH)quinolone J, is described. Thermolysis of arylaminomethylene Meldrums acid derivative 2 is the key step on the preparation of compound 3. These compounds were tested in vitro against trypomastigote forms of Trypanosoma cruzi. Some derivatives were found to have a significant activity.

Helietta apiculata: a tropical weapon against Chagas disease

Abstract The present study pretends to evaluate the in vivo efficacy of the crude chloroform bark extract of Helietta apiculata, then the activity will be compared with the reference drug, benznidazole, in acute Trypanosoma cruzi infected mice when administered by oral route. The chloroformic extract of Helieta apiculata was administered by oral route at 5, 10 and 50 mg/kg daily for two weeks. This study has shown a moderate efficacy of the H. apiculata bark extract in reducing T. cruzi parasitaemia in 42 to 54% after a monitoring of 60 days post-infection and when compared with control groups. Concerning mice mortality, only two only two mice died, one from the control group and the other one from the group threated with 10 mg of the chlorofom extract of H. apiculata, suggesting the potential of H. apiculta extracts as a safe and inexpensive treatment of Chagas disease.

VARIABILIDAD FENOTÍPICA EN POBLACIONES M1 DE SÉSAMO (Sesamum indicum L.) IRRADIADO CON RAYOS GAMMA

The molecular techniques need of protocols that allow determine levels of genetic change inside the populations in different environmental conditions. So much the optimization of the isolation of the DNA, as that of the working conditions of the amplifications, they are fundamental to reach the success of the molecular analyses, therefore the present research has like objective: optimize protocols of extraction of DNA and of the molecular marker type RAPD (Random Amplified Polymorphic DNA) in Anonaceas. For the DNA extraction were used the Kit Nucleon PHYTOpure and DNeasy® of QIAGEN. The working conditions of the protocol of amplification were fittedand changed the concentrations of DNA and of the used chokers. Followed by this, a tes was realized with 10 fatteners of the series OPH and five of the series OPA, to select more polimorphiss. The first results obtained with the Kit Nucleon PHYTOpure showed an DNA of low quality, due to the high fenolization of the vegetable material, not like that with the Kit DNeasy® of QIAGEN, who allowed obtain an DNA of quality, purity and homogeneity to an approximate concentration of 30 ng μ L-1. The biggest amplification products were obtained touse 3 ng μ L-1 of choke and 2 ng μ L-1 of DNA. Four chokers that presented major polymorphism were OPA-16, OPH-03, OPH-13 and OPH-18. The results of this research allowed optimize the working conditions of the technical RAPD for the characterization of the collection ex-situ of Anonaceas under our environmental conditions.Theobroma cacao L. is known in folk medicine as an antiseptic, diuretic and antiparasitic. Foods derived from this plant are rich in natural products of high added value, including phenolic compounds. As in vitro cultivation handle is an alternative source for the production of these metabolites. The present study was conducted to obtain phenolic compounds from callus culture with embryogenic structures. Culture conditions (agitation, light and glucose) were established to increase the concentration of phenols in calluses and elicitors to achieve the increase in callus and excretion into the culture area. The accumulation of phenolic compounds was favored with the additional supplement of glucose, growth in agitation and darkness. The addition of random hydroxylated cyclodextrins allowed the increase in the specific yield of phenols and biomass.The genus Azotobacter and Bacillus have a potential to atmospheric nitrogen fixation, mineral elements solubilization and producing a group of stimulator of vegetal growth substances. In addition, Bacillus is recognizing by its antagonistic activity. The reasons justify its selection with actives principles of biofertilizer products. The presence of fungus diseases in vegetable cultures is a problem for Cuban agriculture. The objective of the present work was to evaluate the antagonistic activity of Azotobacter and Bacillus strains against fungus that caused diseases in vegetables cultures. For those were employed Fusarium chlamydosporum, Corynespora casiicola and Cladosporium oxysporum. All strains belong at the INIFAT collections. For the development of work, “Dual Culture Bring” Method was used with permitting the selections those to possess previous activity and descript, in turn, principle affectations caused to fungi structures. Results emit that inside of two genus exist strains that inhibit the micelial growth. Among strains of Azotobacter, five result promissory against Cladosporium oxysporum, two respond to Fusarium chlamydosporum and only one was effective against Corynespora cassiicola. The activity shows for Bacillus genus is major. In this case, two strains show activity against Corynespora cassiicola, six against Cladosporium oxysporum and eight against Fusarium chlamydosporum. Highlight the finished that exists strains of Azotobactersp capable of inhibit more than one fungi species, which results very new for being quoted few times the genus activity against vegetable pathogens.