Daniele da Silva Ferreira

In vivo Analgesic and Anti-Inflammatory Activities of Ursolic Acid and Oleanoic Acid from Miconia albicans (Melastomataceae)

The aim of this work was to use in vivo models to evaluate the analgesic and anti-inflammatory activities of ursolic acid (UA) and oleanoic acid (OA), the major compounds isolated as an isomeric mixture from the crude methylene chloride extract of Miconia albicans aerial parts, in an attempt to clarify if these compounds are responsible for the analgesic properties displayed by this plant. Ursolic acid inhibited abdominal constriction in a dose-dependent manner, and the result obtained at a content of 40 mg kg-1 was similar to that produced by administration of acetylsalicylic acid at a content of 100 mg kg-1. Both acids reduced the number of paw licks in the second phase of the formalin test, and both of them displayed a significant anti-inflammatory effect at a content of 40 mg kg-1. It is noteworthy that the administration of the isolated mixture, containing 65% ursolic acid/35% oleanolic acid, did not display significant analgesic and anti-inflammatory activities. On the basis of the obtained results, considering that the mixture of UA and OA was poorly active, it is suggested that other compounds, rather than UA and OA, should be responsible for the evaluated activities in the crude extract, since the crude extract samples displayed good activities.

In vivo analgesic and anti-inflammatory activities of Rosmarinus officinalis aqueous extracts, rosmarinic acid and its acetyl ester derivative

Abstract Context: Despite several pharmacological applications of Rosmarinus officinalis L. (Lamiaceae), studies on its analgesic and anti-inflammatory properties have been scarce. Objective: The aim of this work was to use in vivo models to evaluate the analgesic and anti-inflammatory activities of the aqueous extracts obtained from leaves (AEL) and stems (AES) of Rosmarinus officinalis, as well as its isolated compound – rosmarinic acid (RA). We also prepared and assessed the acetyl ester derivative of RA. Materials and methods: The analgesic activity was evaluated using abdominal constriction and formalin tests. For the evaluation of the anti-inflammatory effects, carrageenin-induced paw edema in rats were used. The extracts were used at doses of 100, 200 and 400 mg kg−1 compounds were tested at 10, 20 and 40 mg kg−1. Results: Orally administered AEL, AES and RA were not significantly active at any of the doses tested during the abdominal constriction test; the acetyl ester derivative of RA displayed significant analgesic activity. In the carrageenin-induced paw edema assay, the acetyl derivative of RA at all the tested doses produced significant anti-inflammatory effects and reduced the number of paw licks in the second phase of the formalin test. Discussion and conclusion: The results suggest that the analgesic effects of the acetyl derivative of RA operate via a peripheral-mediated mechanism. The acetyl ester derivative of RA is potentially applicable as a new lead compound for the management of pain and inflammation.

Evaluation of the analgesic activity of extracts of Miconia rubiginosa (Melastomataceae).

The analgesic effects of the hexane, methylene chloride and ethanol extracts of Miconia rubiginosa were evaluated in mice and rats using the acetic acid-induced writhing and hot plate tests. The extracts (100, 200 and 300 mg/kg body wt.) and indomethacin (5 mg/kg body wt.) produced a significant (p < 0.05 and p < 0.01) inhibition of acetic acid-induced abdominal writhing. These same extracts (200 mg/kg body wt.) showed a significant (p < 0.05) antinociceptive effect, lower than that produced by morphine (4 mg/kg body wt.). The fractionation of the methylene chloride extract yielded ursolic and oleanoic acids as the major compounds. Using only gas chromatography, it was possible to identify the following triterpenes in the hexane extract: alpha-amyrin, beta-amyrin, lupeol and beta-sitosterol.

In vitro antiparasitic activity and chemical composition of the essential oil obtained from the fruits of Piper cubeba.

Protozoans of the trypanosomatid family cause the neglected tropical diseases leishmaniasis and trypanosomiasis, for which few drugs are available. In this context our group has recently reported that the essential oil obtained by steam distillation of the fruits of Piper cubeba is active against Schistosoma mansoni. Therefore, we have investigated the in vitro effects of the essential oil against the trypomastigote and amastigote forms of Trypanosoma cruzi isolated from an LLCMK₂ cell line culture and the promastigote forms of Leishmania amazonensis. The in vitro activity of the essential oil against trypomastigotes of T. cruzi increased upon rising concentrations, giving IC₅₀ values of 45.5 and 87.9 µg · mL⁻¹ against trypomastigotes and amastigotes, respectively. The essential oil was not active against L. amazonensis, since it displayed lyses of only 24 % at 400 µg · mL⁻¹, and an IC₅₀ of 326.5 µg · mL⁻¹. Therefore, the essential oil should be further investigated to determine the compounds responsible for the observed activities, as well as its mechanism of action.

Reduction of parasitism tissue by treatment of mice chronically infected with Trypanosoma cruzi with lignano lactones

The reduction of parasitism tissue upon treatment with two lignano lactones, namely (−)- cubebin (CUB) and (−)-hinokinin (HNK), was evaluated in the chronic phase of Chagas’ disease by quantifying the enzyme β-galactosidase expressed by the CL B5 clone strain of Trypanosoma cruzi. Tissue karyometry was also performed. Treatment with the assessed lignans led to a larger reduction in parasitism tissue in all evaluated organs, compared with benznidazole (BZN). Oral treatment with CUB or HNK was more effective. Karyometry results demonstrated that the infected control animals had increased nuclear area compared with uninfected controls, indicating cellular hypertrophy. Results also revealed that use of CUB or HNK was able to significantly prevent this increase, and a slight decrease in the nuclear area was observed, compared with mice treated with BZN. Taken together, these data demonstrate that CUB and HNK could be considered as potential compounds for the development of new drugs for treatment of Chagas’ disease.

Melatonin and dehydroepiandrosterone combination: does this treatment exert a synergistic effect during experimental Trypanosoma cruzi infection?

Abstract:  Previous studies showed that melatonin or dehydroepiandrosterone (DHEA) enhances the immune response against parasitic pathogens. The present study investigated the in vitro activity of melatonin combined with DHEA in a period of 24 hr during the course of in vivo T. cruzi infection. The in vitro activity of melatonin or DHEA alone, as well as together, were tested for the trypomastigote forms (doses ranging from 0.5 to 128 μm). In vitro, neither melatonin nor DHEA alone had any activity against trypomastigote forms, although when the highest concentration of combined melatonin and DHEA was used, it was active against the trypomastigote forms of the parasite. However, for this concentration, a quite toxicity on peritoneal macrophages was observed. For in vivo evaluation, male Wistar rats were infected with the Y strain of T. cruzi. They were orally treated with 10 mg/kg body weight/day of melatonin and subcutaneously with 40 mg/kg body weight/day of DHEA. Treatment with melatonin, DHEA and the association showed a significant reduction in the number of blood trypomastigotes during the acute phase of infection as compared to untreated animals (P < 0.05). A significant increase in the number of macrophages and nitric oxide (NO) concentrations were observed during the peak of parasitaemia with melatonin alone or combined with DHEA. However, with DHEA alone the highest concentration of NO was observed (P < 0.05). Moreover, DHEA treatment increased TNF‐alpha levels during the infection (P < 0.05). These results show that melatonin, DHEA or the combination of both reduces parasitemia during the acute phase of infection. The combined action of both molecules did not exert a synergic action on the host’s ability to fight infection, and it seems that among all treatments DHEA induces a more efficient immune response.

(−)−Hinokinin-loaded poly(d,l-lactide-co-glycolide) microparticles for Chagas disease

The (−)−hinokinin display high activity against Trypanosoma cruzi in vitro and in vivo. (−)−Hinokinin-loaded poly(d,l-lactide-co-glycolide) microparticles were prepared and characterized in order to protect (−)−hinokinin of biological interactions and promote its sustained release for treatment of Chagas disease. The microparticles contain (−)−hinokinin were prepared by the classical method of the emulsion/solvent evaporation. The scanning electron microscopy, light-scattering analyzer were used to study the morphology and particle size, respectively. The encapsulation efficiency was determined, drug release studies were kinetically evaluated, and the trypanocidal effect was evaluated in vivo. (−)−Hinokinin-loaded microparticles obtained showed a mean diameter of 0.862 µm with smooth surface and spherical shape. The encapsulation efficiency was 72.46 ± 2.92% and developed system maintained drug release with Higuchi kinetics. The preparation method showed to be suitable, since the morphological characteristics, encapsulation efficiency, and in vitro release profile were satisfactory. In vivo assays showed significant reduction of mice parasitaemia after administration of (−)−hinokinin-loaded microparticles. Thus, the developed microparticles seem to be a promising system for sustained release of (−)−hinokinin for treatment of Chagas disease.

In vitro trypanocidal activity of the Egyptian plant Schinopsis lorentizii against trypomastigote and amastigote forms of Trypanosoma cruzi.

Chagas’ disease is a chronic illness caused by the protozoan Trypanosoma cruzi. According to estimates, approximately 16-18 million people are infected in Latin American. Plant extracts exhibit a wide variety of secondary metabolites and can play an important role in the discovery of new compounds with biological potential. The in vitro trypanocidal activity of the extracts obtained from six plant species collected in Egypt (Parkia africana, Parkia roxburgi, Lagerstromeia speciosa, Schinopsis lorentzii, Lagerstromeia indica, and Sapindus saponaria) was assayed against trypomastigote and amastigote forms of T. cruzi. The cytotoxic activity of the most active extract was also evaluated by conducting MTT assays. S. lorentzii and S. saponaria were the most active extracts against the trypomastigote form; IC50 values were 9.9 and 27.34 g/mL, respectively. The S. lorentzii extract was also evaluated against the amastigote form (IC50 was 111.5 g/mL). The S. lorentzii extract did not exhibit significant cytotoxic activity. The selectivity index value indicated that this extract was highly selective for the parasite. The S. lorentzii and S. saponaria extracts exhibit trypanocidal activity, probably as a result of the presence of different constituents and their concentrations in the extracts.

Furofuran lignans display schistosomicidal and trypanocidal activities.

Parasitic diseases continue to be a major worldwide health problem, and there is an urgent need for development of therapeutic drugs. This paper describes synthesis of dehydrodiferulic acid dilactone 1 and dehydrodisinapic acid dilactone 2 furofuran lignans by oxidative coupling of ferulic and sinapic acids, respectively. Their schistosomicidal, trypanocidal, and leishmanicidal activities were evaluated in vitro against Schistosoma mansoni adult worms, trypomastigote and amastigotes forms of Trypanosoma cruzi, and promastigote forms of Leishmania amazonensis. Compound 1 did not display significant schistosomicidal activity, but it presented potent trypanocidal activity, since it induced death of trypomastigotes and amastigotes with IC50/24h of 9.3μM and 7.3μM, respectively. Compound 2 had slight trypanocidal and schistosomicidal activities. None of the compounds were active against L. amazonensis. These results demonstrated that furofuran lignans are potentially useful for anti-parasitic drugs development and should be further investigated.

In vitro Activities of Pfaffia glomerata Root Extract, Its Hydrolyzed Fractions and Pfaffic Acid Against Trypanosoma cruzi Trypomastigotes

This article reports on the in vitro activity of the hydroalcoholic extract of Pfaffia glomerata roots, its hydrolyzed fractions, and pfaffic acid against Trypanosoma cruzi. The hydroalcoholic extract obtained from dried, milled P. glomerata roots was submitted to acid hydrolysis followed by partition with CHCl3. The concentrated CHCl3 fraction was suspended in MeOH/H2O and partitioned with hexane (F1), CHCl3 (F2), and AcOEt (F3), in this sequence. The trypanocidal activity of the hydrolyzed extract and its fractions was evaluated in vitro. The hydroalcoholic extract displayed low activity, but fraction F1 was active against trypomastigotes of the Y strain of T. cruzi, with IC50 = 47.89 μg/ml. The steroids campesterol (7.7%), stigmasterol (18.7%), β‐sitosterol (16.8%), Δ7‐stigmastenol (4.6%), and Δ7‐spinasterol (7.5%) were the major constituents of F1, along with fatty acid esters (7.6%) and eight aliphatic hydrocarbons (30.1%). Fractions F2 and F3 exhibited moderate activity, and pfaffic acid, one of the main chemical constituents of these fractions, displayed IC50 = 44.78 μm (21.06 μg/ml). On the other hand, the hydroalcoholic extract of P. glomerata roots, which is rich in pfaffosides, was inactive. Therefore, the main aglycone of pfaffosides, pfaffic acid, is much more active against trypomastigotes of the Y strain of T. cruzi than its corresponding glycosides and should be further investigated.