Antiplasmodial and antileishmanial activities of compounds from Piper tuberculatum Jacq fruits

Abstract INTRODUCTION This study assessed the activity of compounds from Piper tuberculatum against Plasmodium falciparum and Leishmania guyanensis. METHODS The effects of compounds from P. tuberculatum fruits on P. falciparum and L. guyanensis promastigote growth in vitro were determined. Hemolytic action and cytotoxicity in HepG2 and J774 cells were measured. RESULTS Three compounds showed strong antiplasmodial activity and one compound showed strong antileishmanial activity. Two compounds were non-toxic to HepG2 cells and all were toxic to J774 cells. The compounds showed no hemolytic activity. CONCLUSIONS The tested compounds from P. tuberculatum exhibited antiparasitic and cytotoxic effects.

Screening of the in vitro antileishmanial activities of compounds and secondary metabolites isolated from Maytenus guianensis Klotzsch ex Reissek (Celastraceae) chichuá Amazon

Abstract INTRODUCTION Maytenus guianensis is a member of the Celastraceae family that is used in traditional medicine, particularly for its anti-parasitic and anti-cancer effects. To explore the ethnopharmacological potential of this plant, the present study was designed to screen the in vitro antileishmanial activities of extracts and compounds isolated from M. guianensis. METHODS Maytenus guianensis stems and leaves were extracted in acetone, followed by the preparation of eluates and isolation of secondary metabolites using chromatography on a glass column with silica gel as the fixed phase. The chemical components were identified using spectroscopic methods, including one- and two-dimensional nuclear magnetic resonance of hydrogen-1 and carbon-13, mass spectroscopy, and infrared spectroscopy. The anti-Leishmania amazonensis activities of these eluates and compounds were evaluated by direct promastigote counting and viability assays. RESULTS It was found that the hexane bark eluate produced the strongest anti-L. amazonensis effect, with 90-100% inhibition of the promastigote form. The isolated metabolite that produced the best result was tingenone B, followed by a compound formed by the union of tingenone and tingenone B (80-90% inhibition). CONCLUSIONS Maytenus guianensis shows anti-parasite activity that warrants further investigation to determine the mechanisms underlying this antileishmanial effect and to evaluate the pharmacological potential of these eluates and isolated secondary metabolites, while minimizing any adverse effects.

Evaluation of the antiplasmodial and leishmanicidal potential of Myrciaria dubia (Myrtaceae) extract

Abstract INTRODUCTION: Malaria and leishmaniasis are prevalent in tropical regions, which have environmental characteristics that are highly favorable to protozoa and vectors of these diseases; the transmission of these infections in sub-tropical regions, although recognized, represents only a small fraction of cases. Plants are constantly being used in the search for and acquisition of new drugs, and many compounds derived from them have been used to combat various diseases. In this study, we evaluated the action of the dichloromethanolic extract of Myrciaria dubia leaves against the protozoa Plasmodium falciparum, Leishmania amazonensis, Leishmania braziliensis, and Leishmania chagasi through bioassays. METHODS The extract from M. dubia was tested for its anti-P. falciparum activity in an anti-histidine-rich protein II immunosorbent assay. The antileishmanial assays were performed using the resazurin method, while cytotoxicity against human hepatoma (HepG2) strain was determined using the colorimetric MTT [3-(4, 5-dimethyl-2- thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide] method. RESULTS The M. dubia extract presented a half-maximal inhibitory concentration equal to 2.35 (1.05)μg/mL for P. falciparum, 190.73 (6.41) μg/mL for L. amazonensis, and greater than equal to 200µg/mL for L. chagasi and L. braziliensis strains. The cytotoxic concentration for 50% of the cells was above 500μg/mL for HepG2, indicating no toxicity and greater selectivity against parasites. CONCLUSIONS The results obtained indicate the presence of antiplasmodial and leishmanicidal bioactive compounds in the dichloromethanolic extracts of M. dubia leaves, and point towards future studies to elucidate the mechanism of action for each physiological effect.

Antimalarial ethnopharmacology in the Brazilian Amazon / Etnofarmacologia antimalárica na Amazônia Brasileira

The preoccupation to find new drugs for the treatment of malaria is increasing steadily due to the resistance of the parasite, which is a threat to disease control, The present study describes a literature review on the antimalarial ethnopharmacology (Anti-Plasmodium falciparum - in vitro) of the Brazilian Amazon plants, It was found a great diversity of plant species in the Brazilian Amazon with potential for research of new herbal and secondary metabolites with antiplasmodial action, in addition to treating other neglected parasitic diseases, However, for these studies is needed in addition to financial support, the interaction between different laboratories and research groups for the formation of multidisciplinary and interdisciplinary teams, which will enhance the research level in the region and increase the likelihood of new antimalarial drugs discovery...

Está cada vez maior a necessidade em se buscar novos fármacos para o tratamento da malária, principalmente devido à resistência do parasito, o que é uma ameaça ao controle da doença. O presente estudo descreve uma revisão bibliográfica sobre a etnofarmacologia antimalárica (Anti-Plasmodium falciparum - in vitro) de plantas da Amazônia brasileira. Constatou-se uma grande diversidade de espécies vegetais na Amazônia brasileira com potencial para a investigação de novos fitoterápicos e metabólitos secundários com ação antiplasmodial, além do tratamento de outras parasitoses negligenciadas. Porém, para a realização desses estudos são necessários além de apoio financeiro, a interação entre diferentes laboratórios e grupos de pesquisa para a formação de equipes multidisciplinares e interdisciplinares, o que irá potencializar o nível da pesquisa na região e aumentar a probabilidade de descoberta de novos fármacos antimaláricos...