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The tick Rhipicephalus microplus causes significant losses in livestock cattle and has developed increasing resistance to the primary acaricides that are used to treat these infections. The objective of this study was to identify new biomolecules or isolated substances showing acaricidal activity from plants. Larval packet tests were conducted to evaluate the effects of 11 species of plants and three isolated substances (betulinic acid, eugenol, and nerolidol) on R. microplus. An adult female immersion test was performed with the substance that showed the highest larvicidal activity, which was evaluated for inhibition of reproduction. Tests using Licania tomentosa, Hymenaea stigonocarpa, Hymenaea courbaril, Stryphnodendron obovatum, Jacaranda cuspidifolia, Jacaranda ulei, Struthanthus polyrhizus, Chrysobalanus icaco, Vernonia phosphorea, Duguetia furfuracea, and Simarouba versicolor extracts as well as the isolated substance betulinic acid indicated lower acaricidal effects on R. microplus larvae. The extract displaying the best larvicidal activity was the ethanolic extract from L. tomentosa at a concentration of 60%, resulting in a mortality rate of 40.3%. However, nerolidol and eugenol showed larvicidal activity, which was highest for eugenol. Nerolidol caused a 96.5% mortality rate in the R. microplus larvae at a high concentration of 30%, and eugenol caused 100% mortality at a concentration of 0.3%. In the adult immersion test, 5% eugenol was identified as a good biomolecule for controlling R. microplus, as demonstrated by its high acaricidal activity and inhibition of oviposition.

Objectives Warfarin is the most widely used anticoagulant in the world, but it has several limitations including its narrow therapeutic range, need for dose adjustment and high potential for interactions. The simultaneous use of other drugs or even medicinal plants and certain foods could interfere with its therapeutic activity. In this context, this study aims to investigate the in vitro anticoagulant potential and phytochemical constitution of 17 plants selected from a previous clinical cross-sectional study (2014), that investigated the habits of plant utilization among patients taking warfarin. Methods Ethanol extracts and essential oils were evaluated, in vitro, as to their effect in the prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests. Four species that presented aPTT >50 s were selected for phytochemical evaluation. Results Thirteen of the 17 plants selected demonstrated a significant anticoagulant effect in at least one of the evaluated parameters. Citrus sinensis (PT=14.75 and aPTT=53.15), Mentha crispa (aPTT=51.25), Mikania laevigata (PT=14.90 and aPTT=52.10), and Nasturtium officinale (aPTT=50.55) showed greater anticoagulant potential compared to normal plasma pool (PT=12.25 and aPTT=37.73). Chemical profiles of these four species were obtained, and certain compounds were identified: rosmarinic acid from M. crispa and isoorientin from N. officinale. Conclusions Thus, the results of this study could be a useful indicator for clinical practice towards the possibility of interaction between these plants and anticoagulants, although further clinical research is needed taking into consideration the limitations of in vitro studies. These findings also suggest that further research into the action of these plants could be of real clinical value in identifying potential alternative anticoagulant therapies.

Mikania laevigata, popularly known in Brazil as guaco, is widely used for respiratory disorders. As this plant is rich in coumarins, there is evidence of indications that it may cause bleeding and therefore should not be used concomitantly with anticoagulants. The basis of this information is very theoretical, with no clinical evidence of such contraindication. Thus, the aim of this study was to evaluate the in vitro effect of M. laevigata extract on blood coagulation through prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests, fibrinogen plasma concentration, and the new thrombin generation test, which investigate, with high sensibility, hemostatic changes (CAAE 60904316.6.0000.5149), besides evaluating its qualitative micromolecular composition, providing scientific evidence to support the management of patients taking warfarin. Ethanolic extracts of guaco leaves were incubated with a plasma pool of healthy individuals at concentrations of 1.67, 2.26, and 2.86 mg/mL. The presence of flavonoids, tannins, coumarins, and triterpenes was demonstrated by selective reagents in thin layer chromatography. Benzoylgrandifloric acid, cinnamoylgrandifloric acid, o-coumaric acid, coumarin, and quercetin-3-β-glucoside were identified by coinjection in ultraperformance liquid chromatography. The extract at all concentrations prolonged TP and aPPT and reduced the potential for endogenous thrombin potential by the thrombin generation test. The control plasma had endogenous thrombin potential = 1465 nM/min, and after the addition of M. laevigata extract (2.26 mg/mL), this value was reduced to 1087 nM/min, indicating a lower generation of thrombin. Related to fibrinogen plasma concentration, concentrations of 2.26 and 2.86 mg/mL were effective in reducing plasma fibrinogen levels. These results allow us to conclude that the guaco extract demonstrated an anticoagulant effect in vitro, possibly interfering with intrinsic, extrinsic, and common coagulation pathways. A discussion on the contribution of the identified substances to the activity is also present.

Fridericia chica (Bonpl.) L.G. Lohmann, Bignoniaceae, is an Amazonian species known as "pariri" or "crajiru" that is included in the Brazilian National List of Medicinal Plants of Interest to the Unified Health System (Renisus). This herbal remedy is traditionally used as an infusion to treat diarrhea, anemia, inflammation, symptoms of mucositis, and frequent complications of chemotherapy. This study aimed to characterize the chemical profile of the hydroethanolic extract of F. chica and to assess its intestinal anti-inflammatory activity. The chemical profile of the leaves was determined by ultra-performance liquid chromatography coupled to mass spectrometry, and its potential anti-inflammatory activity in the gut was evaluated in mucositis induced by 5-fluorouracil. Three novel compounds from this the species were identified 6,7,3′,4′-tetrahydroxy-5-methoxyflavilium-O-glucuronide, scutellarein-O-glucuronide, and 5-methyl-scutellarein-O-glucuronide, as well as flavones and anthocyanidins that have been previously described. Mice received the hydroethanolic extract (300 mg/kg) for 9 days, and no signs of toxicity were observed. After 72 h of 5-fluorouracil administration, intestinal permeability, bacterial translocation, myeloperoxidase activity, eosinophil peroxidase activity, and histological analyses were performed. Treatment with the analyzed extract was beneficial, as it normalized intestinal permeability, bacterial translocation, myeloperoxidase activity/eosinophil peroxidase and preserved intestinal epithelium architecture. This study provides new insights into the chemical composition and biological activity of the polar extracts from "pariri", an important Amazonian crude medicinal drug.