Anti-leishmanial activity in plants from a Biological Reserve of Costa Rica. Leishmaniosis is an important human disease very difficult to treat. For this reason, many researchers in the world have been looking for anti-leishmanial chemical components present in several plant species. In Costa Rica, since no studies have been done in this field, this work aimed at the search of active chemical components in local plants that may have an activity against Leishmania sp. A total of 67 plants were selected from the Alberto Manuel Brenes Biological Reserve (REBAMB). For these collected plants, fresh or dried hidroalcoholic extracts of root, stem, mature or young leaves, flowers, and immature or mature fruits, were prepared under conventional methods. All extracts were tested for their effect against a strain of Leishmania (OCR with known characteristics). Firstly, by presumptive tests, we selected only those with some activity, and then, more specific studies were done to determine the IC 50 in µg/mL; a promising plant was considered only if at least one of its parts presented an IC 50 <100µg/mL. Under this parameter, the following active plants were obtained and their lowest and highest (23.4 and 97.5). Although the parasitic effect of fresh or dried extracts were almost similar, the fresh material slightly showed better results. That anti-parasitic effect occurred in one or more than four parts of the plant. Most of the active extracts did not produce lysis and aglutination which indicates a low toxicity. Since the species studied are different from those analyzed by other authors, we discuss the importance of these new findings, in relation to the new scientific knowledge, and the possible use of these plants as a leishmaniosis treatment. Rev. Biol. Trop. 62 (3): 1229-1240. Epub 2014 September 01.

RESUMENSe realizó una evaluación in vivo de la actividad antimalárica de las hojas, flores, frutos, corteza y raíz de 25 plantas de la Reserva Biológica Alberto Manuel Brenes (REBAMB), situada en San Ramón, Alajuela, Costa Rica. Las plantas estudiadas fueron Aphelandra aurantiaca (Scheidw.) Lindl., Aphelandra tridentata Hemsl. . Los extractos alcohólicos frescos y secos, fueron evaluados por su actividad inhibitoria de la parasitemia causada por Plasmodium berghei en ratones Swiss. Al realizar las prueba de CI 50, las plantas en que esa actividad fue muy relevante fueron (en mg kg -1 de peso): 12 para la corteza de B. frutescens, 18 para la raíz de H. appendiculata, 14 para la raíz de I. deltoidea, 4 para el fruto inmaduro de M. longipes, 21 para la raíz de N. membranacea, 19 para las hojas tiernas de P. povedae y 16 para el fruto inmaduro de S. tecaphora. Los extractos frescos presentaron una mayor actividad antimalárica que los sometidos a desecación. Este estudio es una contribución más al conocimiento del valor potencial farmacológico de la biodiversidad botánica costarricense.Palabras clave: antimaláricos, Costa Rica, in vivo, plantas, Plasmodium berghei. ABSTRACTAn evaluation of the antimalarial activity of the leaves, flowers, fruits, bark and roots of 25 plants from the Reserve Alberto Manuel Brenes Biological (REBAMB) was performed. The reserve is located in San Ramon, Alajuela, Costa Rica and the plants studied were Aphelandra aurantiaca (Scheidw.) Lindl., Aphelandra tridentata Hemsl. . The fresh and dry alcoholic extracts were evaluated in Swiss mice for their inhibitory activity on multiplication of Plasmodium berghei. When making the test IC 50 , the only plants whose activity (mg kg -1 of body weight) was relevant were: 12 for bark in B. frutescens, 18 for root in H. appendiculata, 14 for root in I. deltoidea, 4 for unripe fruits in M. longipes, 21 for root in N. membranacea, 19 for young leaves in P. povedae and 16 for unripe fruits in S. tecaphora. The fresh extracts showed greater antimalarial activity than those previously dried. This study is a contribution to the knowledge of potential medicinal value of botanical biodiversity of Costa Rica.

Immunosuppressor effect of Trypanosoma musculi (Mastigophora: Trypanosomatidae) on experimental toxoplasmosis. The immunosuppression caused by species of the gender Trypanosoma has been widely documented. The influence over experimental infections with Toxoplasma gondii is evident when using Trypanosoma lewisi, a natural parasite of white rats. We decided to test the effect of Trypanosoma musculi from mice, an organism with very similar biological characteristics to T. lewisi, to see if this trypanosomatid could induce a similar effect. Four groups of Swiss mice were inoculated with T. musculi previously to infection with T. gondii, and we determined the survival of the animals, as well as the number of cysts developed in the brain of survivors. We isolated and tested different strains of T. gondii from different sources. In a first experiment, the animals were previously inoculated with T. musculi at different times prior to the infection with Toxoplasma; this allowed us to determine that the immunosuppression process resulted more evident when T. musculi inoculation was made four days before. In a second experiment, we used different inoculi dose and found that it did not influenced the process. Furthermore, the results were negative when evaluating if the amount of the inoculated trypomastigote influenced the process. In order to demonstrate if there were differences in the immnosuppressive effect, related to Toxoplasma strains, groups of mice were inoculated with brain cysts of TFC, TLP, TLW and TBT strains. Excluding the TLP strain, that resulted to be very pathogenic regardless the previous inoculation with T. lewisi, the other strains kept the same pattern of immunosuppression in mice, whose survival time was shorter as the presence of cysts in the brain was higher. These observations were in agreement with an experimental immunosuppression model, associated with immunosuppressive diseases, specially cancer and AIDS. Rev. Biol. Trop. 61 (2): 981-990. Epub 2013 June 01.

No abstract

"La toxoplasmosis es una enfermedad que aunque casi siempre cursa en una modalidad de tipo crónica usualmente asintomática, eventualmente puede causar problemas en el ser humano como aborto y lesiones oculares. Por tal razón, conocer las posibles fuentes de contaminación al ser humanoes importante y en este estudio se tiene como objetivos revisar la literatura en cuanto a la trasmisión por productos cárnicos y determinar la positividad por Toxoplasma gondii en dos tipos de productos cárnicos para consumo humano, comparando los datos actuales con los obtenidos hace más de 10 años."

Anti-Leishmania (Trypanosomatidae) activity of trans-Z-α-bisabolene epoxide and isolation of safrole, in fruits of Piper auritum (Piperaceae). The leishmaniosis disease incidence is high in tropical regions, and its current treatment has shown severe secondary effects. Considering this problem, many studies have focused on plants, looking for chemical components that have anti-leishmanial activity, and are free of adverse effects for human beings. The purpose of this work was to find a chemical component with this kind of activity in Piper auritum. In a phytochemical screening of this plant, we found some cumarins, terpens, triterpens and reducing sugars; and later, we identified the components trans-Z-α-bisabolene epoxide and Safrol. The first component presented a CI50 of 50.0 µg/mL of anti-Leishmania activity. The Safrol, which is the major component of the essential oils of this plant, did not show antiparasitic activity. These results are discussed considering treatment of leishmaniasis. Rev. Biol. Trop. 66(2): 826-835. Epub 2018 June 01.

Despite the breadth of knowledge about malaria, its transmission, preventive measures and available treatments and its difficulty in controlling the vector and the rapid spread of resistance to current drugs, there is a stimulus to develop new research looking for active molecules. The phytochemical studies of the active extract confirmed the presence of alkaloids, flavonoids, coumarins, tannins, reducing compounds, anthocyanins, terpenes, triterpenes and steroids. In the present work, it was possible to isolate a mixture of isoquinolinic alkaloids from the tender leaves of Nectandra membranacea (Laureaceae) with antimalarial activity. The mixture composed of (-) -gliazovine and (+) -aplogliazovine showed an IC 50 value of 32.18 μg/mL against the P. berghei NK65 strain. It is important to continue with these studies and their chemical components isolated from N. membranacea that could be used as an alternative the treatment of malaria.

Natural concentration of antimalaric components in Tropical arthropods (in vitro). Alcohol, hexane and dichlorometane extracts of 751 samples of Costa Rican arthropods were studied for the presence of antimalaric components. With Plasmodium berghei we set an in vitro model in which the effect of the extract was determined by staining of the parasites with cresil brilliant blue. Active extracts at concentration of 50 mg or less, were considered positive. Promissory extracts were found in the orders Lepidoptera (24.1%), Coleoptera (32.8%), Hemiptera (38.5%) and Polydesmida (81.3%). Since most of the Lepidoptera samples were in the immature stages, the relation with the host plant was analyzed. Cannaceae, Flacourtiaceae, Crisobalanaceae, Lauraceae, Fagaceae, Ulmaceae, Rosaceae, Asteraceae, Rubiaceae, Lauraceae and Caprifoliaceae were related with the Lepidoptera larvae, and an antimalaric effect has been reported in most of these families. In the orders Polydesmida, Opiliones and Blattodea, the extract from adults also had some important effect, probably because all of them fed on plants. Polydesmida and Opiliones have chemical substances that probably serve as defensive purposes; these chemicals could also have some antiparasitic effect. Therefore, the detection of antimalaric components in arthropod species led to the identification of plants with promissory antimalaric components. Rev. Biol. Trop. 56 (2): 473-485. Epub 2008 June 30.