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.

Análise molecular do EXON 10 do gene receptor de TSH em pacientes com tumores da tireóide / Molecular analysis of EXON 10 of TSH receptor gene in patients with thyroid tumors

Introdução: O câncer da tireoide é a quinta neoplasia mais frequente entre as mulheres. A incidência dessa doença vem aumentando substancialmente nos últimos anos. Objetivos: O objetivo do estudo foi determinar a frequência do polimorfismo D727E no gene tshr e associar aos diferentes fenótipos clínicos de tumores de tireoide. Método: 48 pacientes portadores de tumores da tireoide foram operados em hospital de referência de Belém (Pará, Brasil). O grupo-controle foi composto de 131 indivíduos livres de doenças da tireóide. Resultados: Foram encontrados 26 pacientes com tumores malignos e 22 benignos. A frequência alélica do polimorfismo D727E foi de 17,7% em pacientes com tumor de tireoide e 8% no grupo-controle (p<0,03). O polimorfismo D727E mostrou-se em heterozigose em seis pacientes dos 23 com carcinoma papilar e em um com carcinoma folicular. Um paciente com carcinoma folicular e um com carcinoma indiferenciado não apresentaram o polimorfismo. Sete pacientes dos 15 com bócio colóide apresentaram D727E (seis em heterozigose e um em homozigose). Dois dos seis pacientes com adenoma folicular apresentaram o polimorfismo. Discussão: A análise da distribuição da idade de pacientes com câncer mostrou que houve diferença entre os pacientes com diagnóstico de câncer (48,7±14,7 anos) em relação a pacientes com doença benigna (37,8±11,7 anos). A idade de início dos sintomas, que melhor separa os grupos, foi 46 anos. As variáveis gênero feminino, antecedente familiar e idade >41 anos foram associadas à presença do polimorfismo D727E (p = 0,026), o que não foi observado nos pacientes que não apresentavam o polimorfismo. A ocorrência simultânea dos fatores: gênero feminino, antecedente familiar e idade > 46 anos foi relacionada com maior frequência em pacientes com patologia maligna da tireóide (p=0,0047). Conclusões: Estudos adicionais com um maior tamanho amostral são necessários para investigar com mais força estatística a relevância do polimorfismo D727E na gênese do câncer de tireoide e do bócio nodular coloide.

Introduction: Cancer of the thyroid gland is the fifth most common malignancy among women. The disease’s incidence has been increasing over the years. Objectives: The aim of this study, was to determine the frequency of polymorphism D727E tshr gene and its association with different clinical phenotypes of thyroid cancer. Results: 48 patients with thyroid surgical diseases were operated in the city of Belém (Pará, Brazil). The control group was composed by 131 individuals free thyroid diseases. We observed 26 patients with thyroid malignant disease and 22 benign. The allele frequency of polymorphism D727E was 17.7% in patients with thyroid tumor and 8% in the control group (p <0.03). Among malignant thyroid tumors, D727E mutation was found in heterozygosis in 6 of the 23 patients with papillary thyroid carcinoma and in one of two patients with follicular carcinoma. Among the considered benign thyroid tumors: 7 out of 15 patients with nodular goiter colloid showed the mutation (6 heterozygous and 1 homozygous). Two of 6 patients with follicular adenoma showed polymorphism D727E. Discussion: The analysis of the age distribution of patients with thyroid cancer showed that there were differences between patients with cancer diagnosis (48.7 ± 14.7 years), compared to patients with benign disease (37.8 ± 11.7 years). The age of onset of the symptoms that best separates the groups was 46 years. The variables gender (female), family history and age > 41 years were associated with the presence of D727E polymorphism (p = 0.026), which was not observed in patients without this polymorphism. The simultaneous occurrence of gender (female), family history and age > 46 years was associated with increased frequency in patients with malignant thyroid pathology (p = 0.0047). Conclusions: Additional studies with a larger sample size are needed to investigate harder statistical relevance of polymorphism D727E in the genesis of thyroid cancer as well as nodular goiter.