The antiplasmodium effects of a traditional South American remedy: Zanthoxylum chiloperone var. angustifolium against chloroquine resistant and chloroquine sensitive strains of Plasmodium falciparum

Zanthoxylum chiloperone var. angustifolium Engl., Rutaceae, is used in traditional medicine to treat fungal and protozoal infections in the central area of South America. Considering the increasing resistance of Plasmodium falciparum in malarial ridden areas, we explored the anti-plasmodial effects of three compounds isolated from Z. chiloperone. The pyranocoumarin transavicennol and the canthinone alkaloids, canthin-6-one and 5-methoxycanthin-6-one, were found to have IC50 on chloroquine/mefloquine resistant and sensitive strains of P. falciparum of 0.5-2.7, 2.0-5.3 and 5.1-10.4 ƒÊg/mL, respectively. Moreover, the formation of heme adducts by these compounds is described by a novel alternative method based on MS-CID methods. The alkylamide sanshool was also identified, for first time in this plant, in the dichloromethanic and ethanolic extracts and the extracts were found to be notably non-toxic and displayed good anti-plasmodial effects.

Antileishmanial and trypanocidal activity of Brazilian Cerrado plants

The side effects and the emerging resistance to the available drugs against leishmaniasis and trypanosomiasis led to the urgent need for new therapeutic agents against these diseases. Thirty one extracts of thirteen medicinal plants from the Brazilian Cerrado were therefore evaluated in vitro for their antiprotozoal activity against promastigotes of Leishmania donovani, and amastigotes of Trypanosoma cruzi. Among the selected plants, Casearia sylvestris var. lingua was the most active against both L. donovani and T. cruzi. Fifteen extracts were active against promastigotes of L. donovani with concentrations inhibiting 50 percent of parasite growth (IC50) between 0.1-10 æg/ml, particularly those of Annona crassiflora (Annonaceae), Himatanthus obovatus (Apocynaceae), Guarea kunthiana (Meliaceae), Cupania vernalis (Sapindaceae), and Serjania lethalis (Sapindaceae). With regard to amastigotes of T. cruzi, extracts of A. crassiflora, Duguetia furfuracea (Annonaceae), and C. sylvestris var. lingua were active with IC50 values between 0.3-10 æg/ml. Bioassay fractionations of the more active extracts are under progress to identify the active antiparasite compounds.

Comparative evaluation of pyrethroid insecticide formulations against Triatoma infestans (Klug): residual efficacy on four substrates

We investigated the residual efficacy of four insecticide formulations used in Chagas disease vector control campaigns: cyfluthrin 12.5 percent suspension concentrace (SC), lambda-cyhalothrin 10 percent wettable powder (WP), deltamethrin 2.5 percent SC, and 2.5 percent WP on four types of circular blocks of wood, straw with mud, straw with mud painted with lime, and mud containing 5 percent of cement. Three concentrations of these insecticides were tested: the LC90 (previously determined on filter paper), the double of the LC90, and the recommended operational dose. For each bioassay test, 15 third-stage nymphs of Triatoma infestans (Klug) (Hemiptera: Reduviidae) were exposed for 120 h to each treatment at 24 h, 30, 60, 90, and 180 days post-spraying. Mortality rates, moulting history and behaviour were recorded at 24, 48, 72, and 120 h of exposure. Mortality rates were highest during the first 30 days post-spraying. Highest mortality rates (above 50 percent) were observed for deltamethrin 2.5 percent SC and lambda-cyhalothrin 10 percent WP on wood blocks up to three months post-spraying. Mud was the substrate on which treatments showed lowest persistence, with the other two substrates showing intermediate residual efficacy of all treatments. During the first 30 days WP formulations were not as effective as SC flowable formulations but, overall in the longer term, WP gave grater mortality rates of T. infestans nymphs exposed at up to six months post-spraying. Porous surfaces, especially mud, showed most variability presumably due to absorption of the insecticide. In contrast the less porous surfaces (i.e. wood and lime-coated mud) kept mortality rates high for longer post-treatment, irrespective of the insecticide concentration used.

Fipronil insecticide: novel application against triatomine insect vectors of Chagas disease

We investigated the efficacy and the residual effect of fipronil® against two species of triatomine bugs, Triatoma infestans and Rhodnius neglectus, in laboratory conditions measuring concentration-response and residual activity on different surfaces (dried mud and lime coated mud). Lethal concentrations (LC50,90) were determined on filter paper. The higher insecticide efficacy against R. neglectus when compared to T. infestans may be partially attributed to the differences in their biological cycles and genetic structures. Comparison with lambdacyhalothrin wettable powder showed that fipronil mortality rates (above 50 percent) were observed on mud blocks and lime-coated mud blocks up to 3 months when fipronil was sprayed at 100 and 200 mg a.i./m². Residual effect deeply decayed after 3 months; and at 6 months post treatment mortality was not observed. In contrast, lambdacyhalothrin showed a long lasting residual effect on both surfaces up to 6 months. Also, it should be mentioned that fipronil had a slow, but lethal activity on the triatomine bugs when wettable formulations were used on porous surfaces

Inhibiciòn de la agregaciòn plaquetaria por extractos de plantas de uso medicinal en Paraguay / Annual reports 1995 / Inhibition of platelet aggregation by medicinal plants usein Paraguay

Con el propòsito de identificar extractos y luego aislar productos on actividad inhibidoria sobre la agregaciòn plaquetaria in vitro fueron probados 21 extractos alcohòlicos de plantas antitrombòlicos y en transtornos circulatorios e inmunològicos. La inhibiciòn de la agregaciòn se determinò mediante el mètodo turbo-densitomètrico (coagulòmetro AccuStasisTM 1000) midiendo el tiempo de agregaciòn del plasma rico en plaquetas inducido por adenosina 5 difosfato (ADP), colàgeno y epinefrina a las concentraciones iniciales de 2x10-4mo1/L, 2 mg/ml y 1x10-4mo1/L respectivamente y como control positivo de la inhibiciòn de la agregaciòn plaquetaria se usò aspirina a la concentraciòn de 0,1g/ml. La evaluaciòn cualitativa se realizò por apreciaciòn microscòpica (A 100x) de frotis teñidos con Giemsa del agregado plaquetario o nò por los extractos y los controles. Del screening resultò activo el extracto de una planta medicinal perteneciente a la familia Myrtaceae a la concentraciòn de 272ug/ml con los porcentajes de inhibiciòn de 96 por ciento a la concentraciòn de 0,18x10-4mo1/L de ADP y 94,4 por ciento a la concentraciòn de 0,045x10-4mo1/L de ADP. Tambièn resultò activo el extracto de una planta medicinal perteneciente a la familia Flacourtiaceae con un porcentaje de inhibiciòn de 92 por ciento al ser inducido por ADP a la concentraciòn de 0,045x10-4mo1/L. Este estudio indica el potencial de algunos extractos estudiados y justifica el aislamiento de compuestos puros de los extractos activos con mejores propiedades.

Inhibiciòn de la agregaciòn plaquetaria por extractos de plantas de uso medicinal en Paraguay / Annual reports 1995 / Inhibition of platelet aggregation by medicinal plants usein Paraguay

Con el propòsito de identificar extractos y luego aislar productos on actividad inhibidoria sobre la agregaciòn plaquetaria in vitro fueron probados 21 extractos alcohòlicos de plantas antitrombòlicos y en transtornos circulatorios e inmunològicos. La inhibiciòn de la agregaciòn se determinò mediante el mètodo turbo-densitomètrico (coagulòmetro AccuStasisTM 1000) midiendo el tiempo de agregaciòn del plasma rico en plaquetas inducido por adenosina 5 difosfato (ADP), colàgeno y epinefrina a las concentraciones iniciales de 2x10-4mo1/L, 2 mg/ml y 1x10-4mo1/L respectivamente y como control positivo de la inhibiciòn de la agregaciòn plaquetaria se usò aspirina a la concentraciòn de 0,1g/ml. La evaluaciòn cualitativa se realizò por apreciaciòn microscòpica (A 100x) de frotis teñidos con Giemsa del agregado plaquetario o nò por los extractos y los controles. Del screening resultò activo el extracto de una planta medicinal perteneciente a la familia Myrtaceae a la concentraciòn de 272ug/ml con los porcentajes de inhibiciòn de 96 por ciento a la concentraciòn de 0,18x10-4mo1/L de ADP y 94,4 por ciento a la concentraciòn de 0,045x10-4mo1/L de ADP. Tambièn resultò activo el extracto de una planta medicinal perteneciente a la familia Flacourtiaceae con un porcentaje de inhibiciòn de 92 por ciento al ser inducido por ADP a la concentraciòn de 0,045x10-4mo1/L. Este estudio indica el potencial de algunos extractos estudiados y justifica el aislamiento de compuestos puros de los extractos activos con mejores propiedades

Determinaciòn in vitro del porcentaje de mortalidad de Leishmania amazonensis por compuestos puros utilizado el Mètodo de MTT / Annual reports 1993 / In vitro mortality of Leishmania amazonensis whith pure compounds by using MTT Method

Tres alcaloides isoquinòlicos, curine isochondodendrine e isotetrandrine fueron probados contra la forma Leishmania amazonensis in vitro usando el mètodo MTT sal de bromuro de 3-(4,5 dimetil tiazol -2 il)- 2,5- difenil tetrazolio, mètodo calorimètrico ràpido, ùtil para evaluar la supervivencia parasitaria ante la acciòn de compuestos puros seleccionados de acciòn antileishmaniàsica. El cambio de transmitancia fue leìdo utilizando el Lector de Elisa Bio-Rad EIA reader a 570 nm. El porcentaje de mortalidad fue calculado usando el log-probita a diferentes concentraciones de los compuestos puros a 100 ug/ml y 25 ug/ml. Curine demostrò mayor porcentaje de mortalidad a todas las diluciones, lo mismo que isotetrandrine resultò con un mayor porcentaje de mortalidad a todas las diluciones. A la concentraciòn de 100 ug/ml curine e isotetrandrine presentaron 100 por ciento de mortalidad, mientras que isochondendrine 90 por ciento de mortalidad. Tambièn a 50 ug/ml curine e isotetrandrine presentaron 100 por ciento de mortalidad e isochondendrine 50 por ciento de mortalidad. A la concentraciòn de 25 ug/ml curine, isotetrandrine e isochondondendrine presentaron 80 por ciento, 50 por ciento y 10 de mortalidad. Los resultados sugeren que el mètodo MTT podrìa ser ùtil para probar la actividad de compuestos puros contra Leishmania amazonensis

Acción tripanocida y toxicidad de alcaloides bisbenzylisouinqlicos y de un derivado fenolico (FC.108), en ensayos in vivo en ratones c3h infectados con T.cruzi experimentalmente / Annual reports 1994

Un total de sesenta ratones C3H infectados con la cepa epsilon, fueron tratados con alcaloides bisbenzylisoquinolicos (50 ratones) y un derivado fenólico (Fc.108), (10 ratones) con el propósito de determinar la actividad tripanocida in vivo contra el T.cruzi de estas sustancias. También se evaluaron otros efectos como: (actividad protectiva y/o toxicidad) al comparar las lesiones del miocardio por medio de estudios histopatológicos en los ratones tratados y no tratados con estos alcaloides. Se encontraron lesiones histopatogicas en todos los ratones tratados y no tratados pero sólo en estos últimos (grupos controles), se hallaron daños mas severos y nidos de amastigotes de T. cruzi en el miocardio. Se encontraron marcadas diferencias entre el grupo control y el grupo de ratones tratados con cycleanine y curine. Todos los ratones tratados presentaron menor parasitemia y una mayor sobrevida

Actividad tripanocida de productos naturales contra formas sanguineas tripomasrigotes de Trypanosoma Cruzi / Trypanocidal activity of natural products against blood Trypomastigote forms of Trypanosoma cruzi / Annual Reports 1991

Blood trnasfusion is the second most importnatmechanism of transmission of Chagas'disease in both endemic and non-endemic areas. In Latin America, more than 20,000 cases of transmission of the disease, trough blood transfusion, may be occurring. Gentian Violet is currently the only available trypanicidal agent used for treating blood before transfusion. The main disadvantages of this treatment are the time required to allow drug action before transfusion and the coloring of the blood. In vitro trypanocidal effect of plant extracts and that of pure compounds are assessed against trypomastigote blood forms of T. cruzi. The induction of sister chromatid exchange (SCE) in human lypocytes was performed to evaluate mutagenic effects of these compounds. Eight compounds had a high activity against blood forms of T. cruzi at a concentration of 250 mg/ml; namely, daphnandrine, limacine, pheantine, daphnoline and cocsuline. Plumbagin (a naphthoquinone) also showed high trypanicidal activity and has previously been recognized as a leismaniacidal, bactericidal and fungicidal, compound. Daphnoline showed low values for both LC50 (8mg/ml) and LC90 (50mg/ml) and was the only tested compound which did not induce sister chromatid exchange below 10 mg/ml. Therefore, deeper evaluations of these compounds should be considered