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The resistance of gastrointestinal nematodes to anthelmintics has increased the need to evaluate natural products that can replace or assist current strategies to control gastrointestinal nematodes. The objective of this study was to evaluate the effect of decoctions of Lantana camara (DLc), Alpinia zerumbet (DAz), Mentha villosa (DMv) and Tagetes minuta (DTm) on Haemonchus contortus by two in vitro tests. The effects of increasing concentrations of lyophilized decoctions (0.31 to 10mg/ml) were assessed using the egg hatch test (EHT). The decoctions were then tested in the larval artificial exsheathment assay. H. contortus third stage larvae (L3) were exposed to 0.31 mg/ml A. zerumbet and M. villosa decoctions and 0.62 mg/ml T. minuta and L. camara decoctions for 3h and then exsheathment procedure at 10 min intervals. An inhibitor of tannins, polyvinyl polypyrrolidone (PVPP), was used to study if tannins were responsible for the inhibitory effect on hatching and exsheathment of larvae. A. zerumbet, M. villosa and T. minuta showed a dose-dependent effect in the EHT, which did not disappear after the addition of PVPP. No effect was observed for L. camara in the EHT. However, the decoctions inhibited the process of larval exsheathment, which may be related to tannin action because the addition of PVPP reversed the inhibitory effect. A. zerumbet, M. villosa and T. minuta decoctions showed inhibitory activity on H. contortus larvae hatching and exsheathing. The decoctions of these plants could be used to control gastrointestinal nematodes following confirmation of their anthelmintic activity in vivo., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: Myracrodruon urundeuva Fr. Allemao is a common tree in the Caatinga that has been widely used for various medical purposes. Previous studies showed that the ethanol seed extract of M. urundeuva has potent activity against the larval stage of the dengue vector Aedes aegypti. Given this potential insecticidal activity, bioguided separation steps were performed in order to isolate the active compound(s)., Results: The isolation process resulted in only one active chemical compound, identified by infrared spectroscopy and mass spectrometry as m-pentadecadienyl-phenol. This compound presented potent larvicidal and pupicidal activity (LC50 10.16 and 99.06 µg mL(-1) respectively) and great egg hatching inhibitory activity (IC50 49.79 µg mL(-1)). The mode of action was investigated through observations of behavioural and morphological changes performed in third-instar larvae treated with m-pentadecadienyl-phenol solution after 1, 6, 12, 16 and 20 h of exposure. Some changes were observed as flooding of the tracheal system, alterations in siphonal valves and anal gills and lethargy, probably caused by the strong anticholinesterasic activity reported previously., Conclusion: The compound isolated from M. urundeuva seeds, m-pentadecadienyl-phenol, showed potent activity against immature stages of dengue vector, Ae. aegypti, being considered the main larvicidal principle., (Copyright © 2012 Society of Chemical Industry.)

Visceral leishmaniasis (VL) is a zoonotic disease characterized by infection of mononuclear phagocytes by Leishmania chagasi. The primary vector is Lutzomyia longipalpis and the dog is the main domestic reservoir. The control and current treatment of dogs using synthetic drugs have not shown effectiveness in reducing the incidence of disease in man. In attempt to find new compounds with leishmanicidal action, plant secondary metabolites have been studied in search of treatments of VL. This study aimed to evaluate the leishmanicidal activity of Musa paradisiaca (banana tree) and Spondias mombin (cajazeira) chemical constituents on promastigotes and amastigotes of L. chagasi. Phytochemical analysis by column chromatography was performed on ethanol extracts of two plants and fractions were isolated. Thin layer chromatography was used to compare the fractions and for isolation the substances to be used in vitro tests. The in vitro tests on promastigotes of L. chagasi used the MTT colorimetric method and the method of ELISA in situ was used against amastigotes besides the cytotoxicity in RAW 264.7 cells. Of the eight fractions tested, Sm1 and Sm2 from S. mombin had no action against promastigotes, but had good activity against amastigotes. The fractions Mp1 e Mp4 of M. paradisiaca were very cytotoxic to RAW 264.7 cells. The best result was obtained with the fraction Sm3 from S. mombin with IC(50) of 11.26 μg/ml against promastigotes and amastigotes of 0.27 μg/ml. The fraction Sm3 characterized as tannic acid showed the best results against both forms of Leishmania being a good candidate for evaluation in in vivo tests., (Copyright © 2012. Published by Elsevier B.V.)

The aim of this study was to evaluate the anthelmintic activity of hexane (HE), ethyl acetate (EA) and ethanol (EE) extracts obtained from the seeds of Jatropha curcas using the egg hatch inhibition assay (EHA) and the artificial larval exsheathment inhibition assay (LEIA). For the egg hatch assay, HE, EA and EE were used in concentrations of 3.12, 6.25, 12.5, 25 and 50 mg ml(-1), accompanied by a negative control (5% Tween 80) and a positive control (0.025 g ml(-1) thiabendazole). In LEIA, the extracts were tested at a concentration of 1000 μg ml(-1), accompanied by a negative control (PBS). To evaluate the effect of tannins, the extract with the greatest effect was incubated with polyvinyl polypyrrolidone (PVPP). The EE (50 mg ml(-1)) inhibited 99.8% of egg hatching. After the addition of PVPP, the ovicidal effectiveness of EE was reduced to 91.9%. Using the HE and EA, inhibition of egg hatching was 15.3% and 32.2%, respectively. In the LEIA, 18.9% of L3 incubated with EE were exsheathed (p<0.01). The addition of PVPP to EE reversed the inhibitory effect on larval exsheathment. The percentage of exsheathment of L3 incubated with HE (99.6%) and EA (97.8%) did not differ from the control group (p>0.05). The results show that the effects of EE on eggs are not solely due to the tannins. However, these secondary metabolites are implicated in blocking the larval exsheathment., (Copyright © 2011. Published by Elsevier B.V.)

Introduction: Visceral leishmaniasis is endemic in 88 countries, with a total of 12 million people infected and 350 million at risk. In the search for new leishmanicidal agents, alkaloids and acetogenins isolated from leaves of Annona squamosa and seeds of Annona muricata were tested against promastigote and amastigote forms of Leishmania chagasi., Methods: Methanol-water (80:20) extracts of A. squamosa leaves and A. muricata seeds were extracted with 10% phosphoric acid and organic solvents to obtain the alkaloid and acetogenin-rich extracts. These extracts were chromatographed on a silica gel column and eluted with a mixture of several solvents in crescent order of polarity. The compounds were identified by spectroscopic analysis. The isolated compounds were tested against Leishmania chagasi, which is responsible for American visceral leishmaniasis, using the MTT test assay. The cytotoxicity assay was evaluated for all isolated compounds, and for this assay, RAW 264.7 cells were used., Results: O-methylarmepavine, a benzylisoquinolinic alkaloid, and a C37 trihydroxy adjacent bistetrahydrofuran acetogenin were isolated from A. squamosa, while two acetogenins, annonacinone and corossolone, were isolated from A. muricata. Against promastigotes, the alkaloid showed an IC50 of 23.3 µg/mL, and the acetogenins showed an IC50 ranging from 25.9 to 37.6 µg/mL; in the amastigote assay, the IC50 values ranged from 13.5 to 28.7 µg/mL. The cytotoxicity assay showed results ranging from 43.5 to 79.9 µg/mL., Conclusions: These results characterize A. squamosa and A. muricata as potential sources of leishmanicidal agents. Plants from Annonaceae are rich sources of natural compounds and an important tool in the search for new leishmanicidal therapies.

The anthelmintic resistance has limited the control of gastrointestinal nematodes of small ruminants and thus has awakened interest in the study of tanniferous plants as a source of anthelmintics. These experiments were carried out to evaluate the in vitro efficacy of Myracrodruon urundeuva leaf extract (LE) and stem extract (SE) against Haemonchus contortus. An inhibitor of tannins, polyvinyl polypyrrolidone (PVPP), was used to verify if these metabolites are involved in the anthelmintic activity of the extracts. To evaluate the ovicidal effect, H. contortus eggs were incubated with the extracts (0.31 to 5 mg/mL) for 48 h. In the larval artificial exsheathment assay, third-stage larvae of this nematode were incubated with extracts (0.31 mg/mL) for 3 h and then were exposed to a sodium hypochlorite solution. The exsheathment process was evaluated for 60 min. The results were subjected to the Kruskal-Wallis test (P < 0.05). The extracts showed dose-dependent ovicidal effects, although the LE was more effective, inhibiting egg hatching by 97.73% at 1.25 mg/mL, while the SE inhibited hatching by 83.56% at 5 mg/mL. Contact with the extracts blocked the larval exsheathment (P < 0.05). The addition of PVPP confirmed the role of tannins, as there was a substantial reduction in egg hatching and larval exsheathment percentage. These results suggest that M. urundeuva can be used to control gastrointestinal nematodes of small ruminants and that the anthelmintic activity of this plant is probably related to tannins; however, in vivo studies should be conducted.

Seed ethanolic extracts of 21 Brazilian plants were evaluated for ovicidal, larvicidal, and pupicidal activities against insecticide-susceptible (SS) and field-collected (FC) strains of Aedes aegypti (L.) (Diptera: Culicidae), as well as for their effects on nontarget organisms. Myracrodruon urundeuva Fr. Allemao extract was highly toxic to both mosquito strains. Schinopsis brasiliensis Engler extract showed low toxicity and was 38-68 times less toxic to Ae. aegypti larvae than was M. urundeuva extract. The pupicidal activity (LC50) of 14 plant seed extracts ranged between 9 and 433/g/ml, and toxicities were comparable to both mosquito strains. Piptadenia moniliformis Benth. and Luetzelburgia auriculata (Allemao) Ducke extracts showed the highest activities against pupae of FC and SS strains. None of the extracts showed 100% ovicidal activity. In addition, the active extracts did not show high acute toxicity to mice (LD50 > 1.5 g/kg), except that of Enterolobium contortisiliquum (Vell.) Morong. Most of the active extracts exhibited low toxicity against brine shrimp (Artemia sp.) nauplii. The extracts of M. urundeuva, P. moniliformis, and L. auriculata are promising sources of recognized classes of insecticidal compounds with good selectivity against immature stages of Ae. aegypti.

In South America, visceral leishmaniasis is a zoonosis caused by the protozoan species Leishmania infantum (syn. L. chagasi) and is primarily transmitted through the bite of the female Lutzomyia longipalpis. Its main reservoir in urban areas is the dog. The application of control measures recommended by health agencies have not achieved significant results in reducing the incidence of human cases, and the lack of effective drugs to treat dogs resulted in the prohibition of this course of action in Brazil. Therefore, it is necessary to search new alternatives for the treatment of canine and human visceral leishmaniasis. The objectives of this study were to evaluate the in vitro effect of fractions from Aloe vera (aloe), Coriandrum sativum (coriander), and Ricinus communis (castor) on promastigotes and amastigotes of L. infantum and to analyze the toxicity against the murine monocytic cells RAW 264.7. To determine the viability of these substances on 50% parasites (IC50), we used a tetrazolium dye (MTT) colorimetric assay (bromide 3-4.5-dimethylthiazol-2-yl-2,5-dephenyltetrazolium), and on amastigotes we performed an in situ ELISA. All fractions were effective against L. infantum promastigotes and did not differ from the positive control pentamidine (p>0.05). However, the R. communis ethyl acetate and chloroform fractions, as well as the C. sativum methanol fraction, were the most effective against amastigotes and did not differ from the positive control amphotericin B (p>0.05). The R. communis ethyl acetate fraction was the least toxic, presenting 83.5% viability of RAW 264.7 cells, which was similar to the results obtained with amphotericin B (p>0.05). Based on these results, we intend to undertake in vivo studies with R. communis ethyl acetate fractions due the high effectiveness against amastigotes and promastigotes of L. infantum and the low cytotoxicity towards murine monocytic cells., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Lutzomyia longipalpis is the main vector of visceral leishmaniasis in Brazil. The objective was to evaluate the effect of oil from (Azadirachta indica) neem seeds on eggs, larvae and adults of the vector. The insects were captured in the field and kept in the laboratory at +/- 27 °C and 80% relative humidity. Five treatments with different concentrations were performed using two negative controls (distilled water and Tween 80) and a positive control. The eggs were sprayed with the oil at different concentrations and the number of hatched larvae evaluated for 10 days. Mortality of larvae was observed to pupation and adult mortality was observed after 24, 48, and 72 hours. Statistical analysis was performed by Tukey test at 5% probability. The highest oil concentration of eggs obtained 65.16 +/- 3.24% efficacy for reducing egg hatching. The test with larvae showed 67.75 +/- 2.21% efficacy at a concentration of 100 mg.mL⁻¹. In adults, the efficacy of the 100 mg.mL⁻¹ concentration was 96.64 +/- 4.11% after 24 hours. The phytochemical analysis revealed the presence of triterpenes. These results demonstrate the potential use of this oil in the control of this vector.