Caracterização morfológica e morfométrica de estágios larvares de Strongyloides spp, ancilostomídeos e Angiostrongylus spp: subsídios para identificação em amostras ambientais / Morphological and morphometric characterization of larval stages of Strongyloides spp, hookworms and Angiostrongylus spp: subsidies for identification in environmental samples

A identificação precisa de nematódeos de interesse médico-veterinário em amostras de solo ou alimentos é uma ação complexa, devido à grande diversidade de nematódeos no ambiente. O objetivo do estudo foi realizar a caracterização morfológica e morfométrica de diferentes estágios larvários de ancilostomídeos, Strongyloides stercoralis, Strongyloides venezuelensis, Angiostrongylus cantonensis e Angiostrongylus costaricensis, e desenvolver um estudo de similaridade entre espécies do mesmo gênero, a fim de orientar o diagnóstico diferencial com os nematódeos ambientais. As larvas foram fixadas e diversos parâmetros corporais foram mensurados, para os quais foi realizada estatística descritiva e estudo de similaridade. Os resultados médios das larvas padrões foram compatíveis com os descritos para as espécies, com variabilidade em alguns parâmetros. S. stercoralis e S. venezuelensis demonstraram similaridade de 59% para L1 e 79% para L3, com maior diferenciação entre os grupos em relação à extremidade anterior e ao primórdio genital. No pool de larvas de ancilostomídeos, verificou-se uma grande variação nos parâmetros avaliados, especialmente quanto ao comprimento total do corpo. A. cantonensis e A. costaricensis apresentaram 48% de similaridade entre L1 e 76% para L3. Por meio da análise morfométrica e de similaridade verificou-se a possibilidade do aprimoramento do diagnóstico diferencial de nematódeos de origem ambiental. (AU)

Due to the enormous diversity of nematodes in the environment, identifying nematodes of medical and veterinary significance within soil or food samples can be challenging. To facilitate the differential diagnosis with environmental nematodes, this study aimed morphologically and morphometrically characterize various larval stages of hookworms, Strongyloides stercoralis, Strongyloides venezuelensis, Angiostrongylus cantonensi and Angiostrongylus costaricensis. Additionally, a similarity study was conducted among species within the same genus. The larvae were fixated and several body parameters were measured for the analysis, which included a comparison using descriptive statistics. Despite some parameter fluctuation, the average results for standard larvae were consistent with those of the respective species as a whole. The similarity between S. stercoralis and S. venezuelensis was 59% for L1 and 79% for L3, with more pronounced differences observed in the anterior extremity and the genital primordium. The examined parameters exhibited significant variation among the pool of hookworm larvae, particularly concerning the total length of the body. The similarities between A. cantonensis and A. costaricensis larvae ranged from 48% for L1 to 76% for L3. Analyses of morphometric and similarity data provided support for the potential improvement of differentiation between nematodes with environmental origins. This research contributes to enhancing the accuracy of identifying medically and veterinary relevant nematodes present in soil. (AU)

Flavonoids and Sesquiterpene Lactones from Artemisia absinthium and Tanacetum parthenium against Schistosoma mansoni Worms.

Human schistosomiasis, caused by trematode worms of the genus Schistosoma, is one of the most significant neglected tropical diseases, affecting more than 200 million individuals worldwide and praziquantel is the only available drug to treat this disease. Artemisia absinthium L. and Tanacetum parthenium L. are species popularly used as anthelmintics. We investigated the in vitro schistosomicidal activity of crude extracts of A. absinthium (AA) and T. parthenium (TP) and their isolated compounds. AA and TP, at 200 µg/mL, were active, causing 100% mortality of all adult worms. Chromatographic fractionation of AA leads to isolation of artemetin and hydroxypelenolide, while santin, apigenin, and parthenolide were isolated from TP. Artemetin, hydroxypelenolide, santin, and apigenin, at 100 µM, were inactive against adult worms. Parthenolide (12.5 to 100 µM) caused 100% mortality, tegumental alterations, and reduction of motor activity of all adult worms of S. mansoni, without affecting mammalian cells. Confocal laser scanning microscopy showed tegumental morphological alterations and changes on the numbers of tubercles of S. mansoni worms. This report provides the first evidence for the in vitro activity of parthenolide against adult worms of S. mansoni, opening the route to further schistosomicidal studies with this compound.

Schistosomicidal activity and docking of Schistosoma mansoni ATPDase 1 with licoflavone B isolated from Glycyrrhiza inflata (Fabaceae).

Schistosomiasis is one of the world's major public health problems, and its treatment is widely dependent on praziquantel (PZQ), the only available drug. Schistosoma mansoni ATP diphosphohydrolases are ecto-enzymes localized on the external tegumental surface of S. mansoni and considered an important target for action of new drugs. In this work, the in vitro schistosomicidal activity of the crude extract of Glycyrrhiza inflata roots (GI) and its isolated compounds echinatin, licoflavone A and licoflavone B were evaluated against S. mansoni adult worms. Results showed that GI (200 µg/mL) was active against adult schistosomes, causing 100% mortality after 24 h of incubation. Chromatographic fractionation of GI led to isolation of echinatin, licoflavone A and licoflavone B. Licoflavone B (25-100 µM) caused 100% mortality, tegumental alterations, and reduction of oviposition and motor activity of all adult worms, without affecting mammalian Vero cells. Confocal laser scanning microscopy showed tegumental morphological alterations and changes on the numbers of tubercles of S. mansoni worms in a dose-dependent manner after incubation with licoflavone B. Licoflavone B also showed high S. mansoni ATPase (IC50 of 23.78 µM) and ADPase (IC50 of 31.50 µM) inhibitory activities. Docking studies predicted different interactions between licoflavone B and S. mansoni ATPDase 1, corroborating with the in vitro inhibitory activity. This report demonstrated the first evidence for the schistosomicidal activity of licoflavone B and suggests that its mechanism of action involve the inhibition of S. mansoni ATP diphosphohydrolases.

Synthesis and evaluation of new oxamniquine derivatives.

Oxamniquine derivatives were synthesized and evaluated as novel schistosomicide agents. Oxamniquine (1,2,3,4-tetrahydro-2-[[(1-methylethyl)amino]methyl]-7-nitro-6-quinolinemethanol) was submitted to the Mannich reaction, using formaldehyde, paraformaldehyde and acetaldehyde as reagents, and gave three unexpected products: two of them were cyclized on the alkylamine side chain and another etherified on the aminequinolinemethanol group. The three compounds were biologically evaluated using mice infected with Schistosoma mansoni and showed promising activities, but had higher toxicities. For studies on structure-activity relationships, results demonstrate that the side alkylamine group can be modified with preserved activity, but that this modification is associated with increased toxicity.