Acaricide action on Rhipicephalus microplus of extracts, fractions and compounds obtained from Lecythis lurida (Lecythidaceae)

http://dx.doi.org/10.5007/2175-7925.2015v28n4p119O Rhipicephalus microplus destaca-se entre os ectoparasitas de maior importância econômica na bovinocultura. O controle do carrapato bovino tem sido dificultado pela resistência de populações aos acaricidas sintéticos. Dessa forma, o objetivo do trabalho foi avaliar a eficiência carrapaticida de extratos, frações e metabólitos secundários de Lecythis lurida no combate ao R. microplus. Esse é o primeiro relato de estudo químico e biológico da espécie L. lurida, conhecida no cerrado leste do Maranhão, onde foi coletada, como sapucarana. Destaca-se pela sua densidade populacional e também pela exuberância de sua floração, muito visitada por várias espécies de abelhas. A investigação química revelou que os compostos obtidos da espécie L. lurida se agrupam na classe dos triterpenos, entre eles o friedelanol e a friedelina, esse último, como composto majoritário, além de misturas de triterpenos e esteroides. A avaliação da atividade carrapaticida sobre larvas e fêmeas ingurgitadas de carrapatos da espécie R. microplus revelou que apenas alguns extratos e frações apresentaram atividade moderada, considerando como parâmetros as concentrações testadas dos extratos e frações obtidos a frio e a quente de folhas e cascas de L. lurida.http://dx.doi.org/10.5007/2175-7925.2015v28n4p119Rhipicephalus microplus (cattle tick) stands out as one of the most economically important ectoparasites of cattle, but controlling this species has been difficult because populations are resistant to synthetic acaricides. The goal of this study was to evaluate the efficiency of Lecythis lurida extracts, fractions and secondary metabolites against R. microplus. This is the first report of a phytochemical and biological study of L. lurida, which was collected in the cerrado of eastern Maranhão where it is known as sapucarana. In this region, L. lurida stands out for its population density and flowers, which are commonly visited by several bee species. The compounds obtained from L. lurida during this study were triterpenoids, such as friedelanol and friedelin (the major compound), in addition to mixtures of triterpenes and steroids. The evaluation of acaricide activity on larvae and engorged ticks of R. microplus revealed that only some of the extracts and fractions, obtained from the leaves and bark of L. lurida, had moderate activity

Antiparasitic activities of hydroethanolic extracts of Ipomoea imperati (Vahl) Griseb. (Convolvulaceae).

Ipomoea imperati is widely used in tropical areas to treat several pathological conditions. The effect of this plant against parasitic species has not been investigated even being used for this purpose in the Brazilian northeastern. This study aimed to evaluate the anthelmintic and acaricide potential of a hydroethanolic extract of I. imperati leaves and stolons. I. imperati leaves and stolons were crushed and subjected to maceration in ethanol 70% (v/v), after which the solvent was removed using a rotary evaporator. The chromatographic profile of the extract was obtained by UV Spectrum high-performance liquid chromatography and compounds were identified by liquid chromatography/electrospray ionization tandem mass spectrometry. Identification of the compounds present in the extract was achieved by comparing their retention times and UV spectra with data in the literature. Anthelmintic activity was evaluated by larval exsheathment inhibition assays using Haemonchus contortus larvae and five concentrations of each extract ranging from 0.07 to 1.2 mg/mL. Acaricide activity was evaluated via larval immersion of Rhipicephalus microplus in eight concentrations of each extract ranging from 5.0 to 25.0 mg/mL. Live and dead larvae were counted after 24 hours. The median inhibitory concentration (IC50) for H. contortus larvae and the median lethal concentration (LC50) for R. microplus larvae were calculated. Twelve compounds were observed in the hydroethanolic extract of leaves, with a predominance of the aglycone form of flavonoids and tannins. This extract was effective against H. contortus larvae, presenting an average inhibitory concentration of 0.22 mg/mL, but showed no activity toward R. microplus larvae. The stolon hydroethanolic extract presented 11 compounds, with phenolic acids and glycosylated flavonoids prevailing. This extract showed low activity on R. microplus and no effect on inhibiting H. contortus larval exsheathment at the concentrations tested. This study is the first to assess the anthelmintic and acaricidal activities of I. imperati. Data reported confirm promising potential of I. imperati leaves hydroethanolic extract against H. contortus. This effect could be due to its secondary compounds presents in this extract, such as procyanidin, kaempferol, isoquercitrin and rutin

Leishmanicidal and immunomodulatory activity of Terminalia catappa in Leishmania amazonensis in vitro infection

Leishmaniases are infectious-parasitic diseases that impact public health around the world. Antileishmanial drugs presented toxicity and increase in parasitic resistance. Studies with natural products show an alternative to this effect, and several metabolites have demonstrated potential in the treatment of various diseases. Terminalia catappa is a plant species with promising pharmaceutical properties. The objective of this work was to evaluate the therapeutic potential of extracts and fractions of T. catappa on Leishmania amazonensis and investigate the immunomodulatory mechanisms associated with its action. In anti-Leishmania assays, the ethyl acetate fraction exhibited activity against promastigotes (IC50 86.07 ± 1.09 μg/mL) and low cytotoxicity (CC50 517.70 ± 1.68 μg/mL). The ethyl acetate fraction also inhibited the intracellular parasite (IC50 25.74 ± 1.08 μg/mL) with a selectivity index of 20.11. Treatment with T. catappa ethyl acetate fraction did not alter nitrite production by peritoneal macrophages stimulated with L. amazonensis, although there was a decrease in unstimulated macrophages treated at 50 μg/mL (p = 0.0048). The T. catappa ethyl acetate fraction at 100 μg/mL increased TNF-α levels (p = 0.0238) and downregulated HO-1 (p = 0.0030) and ferritin (p = 0.0002) gene expression in L. amazonensis-stimulated macrophages. Additionally, the total flavonoid and ellagic acid content for ethyl acetate fraction was 13.41 ± 1.86 mg QE/g and 79.25 mg/g, respectively. In conclusion, the T. catappa ethyl acetate fraction showed leishmanicidal activity against different forms of L. amazonensis and displayed immunomodulatory mechanisms, including TNF-α production and expression of pro and antioxidant genes

The first assessment of the stress inducible defense of Leucaena leucocephala with acaricidal potential effect against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

Abstract Plants respond to wounding caused by mechanical stress or herbivory by synthesizing defense proteins. There are no studies reporting the action of induced plant proteins against ticks. The aim of this study was to investigate the effect of mechanically wounded Leucaena leucocephala leaves against Rhipicephalus (Boophilus) microplus. Initially, we carried out time course experiments to evaluate the impact of mechanical wounding on the protein content and the peroxidase, catalase and protease inhibitor activities in L. leucocephala. We then evaluated the acaricidal activity on R. (B.) microplus from protein extract collected from L. leucocephala after mechanical wounding. L. leucocephala leaves were artificially wounded, and after 6, 12, 24 and 48h, the leaves were collected for protein extraction. Quantitative and qualitative analyses of the proteins were performed. The protein content and peroxidase and protease activities increased 12h after wounding, and the acaricidal activity of this protein extract was evaluated using engorged R. (B.) microplus females. The protein extract obtained after wounding reduced egg production (8.5%) compared to those without wounding. Furthermore, the extract reduced egg hatching by 47.7% and showed an overall efficacy of 56.3% at 0.1 mgP/mL of the protein. We demonstrated that L. leucocephala defensive proteins could be effective against R. (B.) microplus

Antibacterial, Antibiofilm, and Antischistosomal Activity of Montrichardia linifera (Arruda) Schott (Araceae) Leaf Extracts

With a broad ethnopharmacological tradition in Brazil, Montrichardia linifera has been reported as a potent antirheumatic, antimicrobial, and antiprotozoan agent. However, there is a lack of studies on its effect on bacterial biofilm formation and Schistosoma mansoni worms. This study reports the effects of antibacterial, antibiofilm, and antischistosomal properties of leaf extracts of M. linifera. Phytochemical screening and identification of the main compounds of the extracts were performed. All the extracts evaluated showed antibacterial activity at the concentrations tested. We checked for the presence of flavonoids and derivatives of phenolic acids by the presence of spectra with bands characteristic of these classes in the sample analyzed. The antibacterial assays showed that the best MICs corresponded to 125 µg/mL against Enterococcus faecalis ATCC 29212 in all fractions. The ethanolic and methanolic extracts showed the ability to inhibit biofilm of Staphylococcus aureus ATCC 25123. For the antischistosomal activity, only the acetone and ethyl acetate extracts had a significant effect against helminths, with potent activity at a concentration of 50 µg/mL, killing 100% of the worms after 72 h of incubation. The M. linifera leaf extracts showed antibacterial activity, biofilm inhibition capacity, and anthelmintic activity against S. mansoni

Contributions of γ-Aminobutyric Acid (GABA) Receptors for the Activities of <i>Pectis brevipedunculata</i> Essential Oil against <i>Drosophila suzukii</i> and Pollinator Bees

The γ-aminobutyric acid (GABA) receptors play pivotal roles in the transmission of neuronal information in the nervous system of insects, which has led these proteins to be targeted by synthetic and natural products. Here, we assessed the insecticidal potential of the essential oil of Pectis brevipedunculata (Gardner) Sch. Bip., a neotropical Asteraceae plant used in traditional medicine, for controlling Drosophila suzukii (Matsumura) adults by feeding exposure. By using in silico approaches, we disentangle the contribution of GABA receptors and other potential neuronal targets (e.g., acetylcholinesterase, glutathione-S-transferases) in insects that may explain the essential oil differential activities against D. suzukii and two essential pollinator bees (Apis mellifera Linnaeus and Partamona helleri Friese). Neral (26.7%) and geranial (33.9%) were the main essential oil components which killed D. suzukii with an estimated median lethal concentration (LC50) of 2.25 µL/mL. Both pollinator forager bee species, which would likely contact this compound in the field, were more tolerant to the essential oil and did not have their diet consumptions affected by the essential oil. Based on the molecular predictions for the three potential targets and the essential oil main components, a higher affinity of interaction with the GABA receptors of D. suzukii (geranial −6.2 kcal/mol; neral −5.8 kcal/mol) in relation to A. mellifera (geranial −5.2 kcal/mol; neral −4.9 kcal/mol) would contribute to explaining the difference in toxicities observed in the bioassays. Collectively, our findings indicated the involvement of GABA receptors in the potential of P. brevipedunculata essential oil as an alternative tool for controlling D. suzukii