Antibacterial, Antiparasitic, and Cytotoxic Activities of Chemical Characterized Essential Oil of Chrysopogon zizanioides Roots.

This study aimed to investigate the chemical composition as well as the antibacterial, antiparasitic, and cytotoxic potentialities of the Brazilian Chrysopogon zizanioides root essential oil (CZ-EO) In addition, CZ-EO cytotoxicity to LLCMK2 adherent epithelial cells was assessed. The major compounds identified in CZ-EO were khusimol (30.0 ± 0.3%), ß-eudesmol (10.8 ± 0.3%), α-muurolene (6.0 ± 0.1%), and patchouli alcohol (5.6 ± 0.2%). CZ-EO displayed optimal antibacterial activity against Prevotella nigrescens, Fusobacterium nucleatum, Prevotella melaninogenica, and Aggregatibacter actinomycetemcomitans, with Minimum Inhibitory Concentration (MIC) values between 22 and 62.5 µg/mL and Minimum Bactericidal Concentration (MBC) values between 22 and 400 µg/mL. CZ-EO was highly active against the L. amazonensis promastigote and amastigote forms (IC50 = 7.20 and 16.21 µg/mL, respectively) and the T. cruzi trypomastigote form (IC50 = 11.2 µg/mL). Moreover, CZ-EO showed moderate cytotoxicity to LLCMK2 cells, with CC50 = 565.4 µg/mL. These results revealed an interesting in vitro selectivity of CZ-EO toward the L. amazonensis promastigote and amastigote forms (Selectivity Index, SI = 78.5 and 34.8, respectively) and the T. cruzi trypomastigote form (SI = 50.5) compared to LLCMK2 cells. These results showed the promising potential of CZ-EO for developing new antimicrobial, antileishmanial, and antitrypanosomal drugs.

In vitro anti-trypanosomal potential of kaurane and pimarane semi-synthetic derivatives.

As part of the search for anti-trypanosomal agents, this work presents the production of sixteen derivatives. All of them were obtained from two natural diterpenes, one with kaurane skeleton (ent-kaurenoic acid) and other with a pimarane skeleton (ent-pimaradienoic acid). Then, the eighteen compounds were assayed against epimastigote form of Trypanosoma cruzi, with the derivatives showing increase of activity in relation to their precursors. Moreover, the most active derivative presented an IC50 <12.5 µM (estimated 0.8 µM), lower than Benznidazole (IC50 = 9.8 µM), used as control. The esterification of acid diterpenes showed to be an interesting way in the search for anti-trypanosomal agents.

Trypanocidal Activity of Dysphania ambrosioides, Lippia alba, and Tetradenia riparia Essential Oils against Trypanosoma cruzi.

Despite the current treatments against Chagas Disease (CD), this vector-borne parasitic disease remains a serious public health concern. In this study, we have explored the in vitro and/or in vivo trypanocidal and cytotoxic activities of the essential oils (EOs) obtained from Dysphania ambrosioides (L.) Mosyakin & Clemants (Amaranthaceae) (DA-EO), Lippia alba (Mill.) N.E. Brown (Verbenaceae) (LA-EO), and Tetradenia riparia (Hochst.) Codd (Lamiaceae) (TR-EO) grown in Brazil Southeast. DA-EO was the most active against the trypomastigote and amastigote forms in vitro; the IC50 values were 8.7 and 12.2 µg mL-1 , respectively. The EOs displayed moderate toxicity against LLCMK2 cells, but the DA-EO showed high selectivity index (SI) for trypomastigote (SI=33.2) and amastigote (SI=11.7) forms. Treatment with 20 mg/kg DA-EO, LA-EO, or TR-EO for 20 days by intraperitoneal administration reduced parasitemia by 6.36 %, 4.74 %, and 32.68 % on day 7 and by 12.04 %, 27.96 %, and 65.5 % on day 9. These results indicated that DA-EO, LA-EO, and TR-EO have promising trypanocidal potential in vitro, whereas TR-EO has also potential trypanocidal effects in vivo.

In Vivo and in Silico Trypanocidal Activity Evaluation of (-)-Cubebin Encapsulated in PLGA Microspheres as Potential Treatment in Acute Phase.

In this study, the trypomastigotes of a Y strain of Trypanosoma cruzi were inoculated intraperitoneally into male BALB/c mice weighing approximately 25 g each, which were divided into groups for evaluation of the trypanocidal activity. For the treatment of experimental groups, encapsulated and unencapsulated (-)-cubebin, Benznidazole, and two groups as negative controls were used. The encapsulated (-)-cubebin showed a 68.1 % encapsulation efficiency. The parasitemia peak of substances remained around the 9th day after the observed reduction in the number of circulating trypomastigotes. The encapsulated (-)-cubebin and (-)-cubebin unloaded showed a decrease of 61.3 % and 58.5 % in the number of parasites as compared to the negative control, respectively. Moreover, animals treated with encapsulated (-)-cubebin had a higher survival time as compared to the other groups. In conclusion, the results obtained were more promising for encapsulated (-)-cubebin as compared to unloaded particles.

(±)-Licarin A and its semi-synthetic derivatives: In vitro and in silico evaluation of trypanocidal and schistosomicidal activities.

This paper reports the synthesis of (±)-licarin A 1, a dihydrobenzofuran neolignan, resultant of an oxidative coupling reaction of isoeugenol and horseradish peroxidase (HRP) enzyme. Following, three semi-synthetic derivatives from this compound were obtained: benzylated (±)-licarin A 2, methylated (±)-licarin A 3 and acetylated (±)-licarin A 4. After structural elucidation and assignment by Nuclear Magnetic Resonance of 1H, 13C and DEPT, all compounds were evaluated in vitro against Trypomastigote forms of Trypanosoma cruzi (T. cruzi), the etiologic agent of Chagas disease, and Schistosoma mansoni (S. mansoni) worms, the etiologic agent of schistosomiasis. Compound (4) was the most active against S. mansoni adult worms, displaying worm viability reduction at 25 µM and mortality of all worms at 100 and 200 µM within 24 h. Compound 1 was the second most active, showing worm viability reduction at 50 µM and mortality of 25% and 100% of worms in 24h at concentrations of 100 and 200 µM, respectively. In addition, theoretical calculations aiming at finding molecular properties that showed the correlation for schistosomicidal and trypanocidal activities of (±)-licarin A and three of its semi-synthetic derivatives were also performed.

In vitro antiparasitic activity and chemical composition of the essential oil from Protium ovatum leaves (Burceraceae)

ABSTRACT Leishmaniasis and trypanosomiasis are globally widespread parasitic diseases which have been responsible for high mortality rates. Since drugs available for their treatment are highly hepatotoxic, nephrotoxic and cardiotoxic, adherence to therapy has been affected. Thus, the search for new, more effective and safer drugs for the treatment of these diseases is necessary. Natural products have stood out as an alternative to searching for new bioactive molecules with therapeutic potential. In this study, the chemical composition and antiparasitic activity of the essential oil from Protium ovatum leaves against trypomastigote forms of Trypanosoma cruzi and the promastigote forms of Leishmania amazonensis were evaluated. The essential oil was promising against trypomastigote forms of T. cruzi (IC50= 28.55 μg.mL-1) and L. amazonensis promastigotes (IC50 = 2.28 μg.mL-1). Eighteen chemical constituents were identified by Gas Chromatography coupled to Mass Spectrometry (GC-MS) in the essential oil, whose major constituents were spathulenol (17.6 %), caryophyllene oxide (16.4 %), β-caryophyllene (14.0 %) and myrcene (8.4 %). In addition, the essential oil from P. ovatum leaves had moderate cytotoxicity against LLCMK2 adherent epithelial cell at the concentration range under analysis (CC50 = 150.9 μg.mL-1). It should be highlighted that this is the first report of the chemical composition and anti-Trypanosoma cruzi and anti-Leishmania amazonensis activities of the essential oil from Protium ovatum leaves.

In vitro schistosomicidal activity of the lignan (-)-6,6'-dinitrohinokinin (DNHK) loaded into poly(lactic-co-glycolic acid) nanoparticles against Schistosoma mansoni.

CONTEXT: (-)-6,6'-Dinitrohinokinin (DNHK) display remarkable antiparasitic activity and was, therefore, incorporated into a nanoparticle formulation. OBJECTIVE: Incorporation of DNHK in poly lactic-co-glycolic acid (PLGA) nanoparticles aiming to improve its biological activities. MATERIALS AND METHODS: Synthesis, characterization and incorporation of DNHK into glycolic acid (PLGA) nanoparticles by nanoprecipitation method. The nanoparticles were characterized by ultraviolet-visible spectroscopy, X-ray diffraction, field emission electron microscopic scanning mansoni (FESEM), and dynamic light scattering (DLS). For the in vitro test with Schistosoma mansoni, the DNHK-loaded PLGA was diluted into the medium, and added at concentrations 10-200 µM to the culture medium containing one adult worm pair. The parasites were kept for 120 h and monitored every 24 h to evaluate their general condition, including: pairing, alterations in motor activity and mortality. RESULTS: The loaded PLGA nanoparticles gave an encapsulation efficiency of 42.2% and showed spherical characteristics in monodisperse polymeric matrix. The adult worm pairs were separated after 120 h of incubation for concentrations higher than 50 µM of DNHK-loaded PLGA. The groups incubated with 150 and 200 µM of DNHK-loaded PLGA for 24 and 120 h killed 100% of adult worms, afforded LC50 values of 137.0 ± 2.12 µM and 79.01 ± 1.90 µM, respectively, which was similar to the effect displayed by 10 µM of praziquantel. DISCUSSION AND CONCLUSIONS: The incorporation of DNHK-loaded showed schistosomicidal activity and allowed its sustained release. The loaded PLGA system can be administered intravenously, as well as it may be internalized by endocytosis by the target organisms.

In vitro antiparasitic activity and chemical composition of the essential oil from Protium ovatum leaves (Burceraceae).

Leishmaniasis and trypanosomiasis are globally widespread parasitic diseases which have been responsible for high mortality rates. Since drugs available for their treatment are highly hepatotoxic, nephrotoxic and cardiotoxic, adherence to therapy has been affected. Thus, the search for new, more effective and safer drugs for the treatment of these diseases is necessary. Natural products have stood out as an alternative to searching for new bioactive molecules with therapeutic potential. In this study, the chemical composition and antiparasitic activity of the essential oil from Protium ovatum leaves against trypomastigote forms of Trypanosoma cruzi and the promastigote forms of Leishmania amazonensis were evaluated. The essential oil was promising against trypomastigote forms of T. cruzi (IC50= 28.55 µg.mL-1) and L. amazonensis promastigotes (IC50 = 2.28 µg.mL-1). Eighteen chemical constituents were identified by Gas Chromatography coupled to Mass Spectrometry (GC-MS) in the essential oil, whose major constituents were spathulenol (17.6 %), caryophyllene oxide (16.4 %), ß-caryophyllene (14.0 %) and myrcene (8.4 %). In addition, the essential oil from P. ovatum leaves had moderate cytotoxicity against LLCMK2 adherent epithelial cell at the concentration range under analysis (CC50 = 150.9 µg.mL-1). It should be highlighted that this is the first report of the chemical composition and anti-Trypanosoma cruzi and anti-Leishmania amazonensis activities of the essential oil from Protium ovatum leaves.

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/H2 O 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%), ß-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.

Antibacterial activity of (-)-cubebin isolated from Piper cubeba and its semisynthetic derivatives against microorganisms that cause endodontic infections

Abstract Recent publications have highlighted the numerous biological activities attributed to the lignan (-)-cubebin (1), Piper cubeba L. f., Piperaceae, and ongoing studies have focused on its structural optimization, in order to obtain derivatives with greater pharmacological potential. The aim of this study was the obtainment of (1), its semisynthetic derivatives and evaluation of antibacterial activity. The extract of the seeds of P. cubeba was chromatographed, subjected to recrystallization and was analyzed by HPLC and spectrometric techniques. It was used for the synthesis of: (-)-O-methylcubebin (2), (-)-O-benzylcubebin (3), (-)-O-acetylcubebin (4), (-)-O-(N, N-dimethylamino-ethyl)-cubebin (5), (-)-hinokinin (6) and (-)-6.6'-dinitrohinokinin (7). The evaluation of the antibacterial activity has been done by broth microdilution technique for determination of the minimum inhibitory concentration and the minimum bactericidal concentration against Porphyromonas gingivalis, Prevotella nigrescens, Actinomyces naeslundii, Bacteroides fragilis and Fusobacterium nucleatum. It was possible to make an analysis regarding the relationship between structure and antimicrobial activity of derivatives against microorganisms that cause endodontic infections. The most promising were minimum inhibitory concentration =50 µg/ml against P. gingivalis by (2) and (3), and minimum inhibitory concentration =100 µg/ml against B. fragilis by (6). Cytotoxicity assays demonstrated that (1) and its derivatives do not display toxicity.

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.

Natural products and Chagas' disease: the action of triterpenes acids isolated from Miconia species / Productos naturales y mal de Chagas: la acción de los ácidos triterpenos aislados de especies de Miconia / Produtos naturais e doença de Chagas: a ação de triterpenos ácidos isolados de espécies de Miconia

The protozoan Trypanosoma cruzi causes Chagas' disease, a neglected illness that remains a relevant public health concern in Latin America. In Brazil, Benznidazole is available for its treatment. This compound is effective against circulating forms of the parasite in the acute phase of the disease, but its efficacy during the chronic stage is debatable. The search for new medications that can treat Chagas' disease is therefore mandatory. Natural sources display a wide range of secondary metabolites and may play an important role in the discovery of new potential drugs. Miconia is one of the largest genus of the family Melastomataceae and includes approximately 1,000 plant species; Brazil alone is home to approximately 250 of these species, which exist in forests and savannas. Studies on the various biological activities of the Miconia species have reported promising results. Several researchers have screened these plants as well as their extracts in vitro against trypomastigote forms of T. cruzi, which displayed significant trypanocidal activity. It has been demonstrated that the presence of ursolic and oleanolic determines this biological activity.

El protozoario Trypanosoma cruzi causa mal de Chagas, enfermedad que aún es problema de salud pública relevante en América Latina. El fármaco disponible en Brasil para el tratamiento es benznidazol. Este compuesto es eficaz contra la forma de circulación del parásito en la fase aguda de la enfermedad, pero su eficacia durante la fase crónica es discutible. Por lo tanto, la búsqueda de nuevos medicamentos que pueden tratar el mal de Chagas es necesaria. Las fuentes naturales presentan amplia gama de metabolitos secundarios y pueden desempeñar papel importante en el descubrimiento de nuevas drogas potenciales. Miconia es un género de los más grandes perteneciente a la familia Melatomateceae, incluyendo cerca de 1.000 especies de plantas; sólo en Brasil hay aproximadamente 250 de estas especies en florestas y sabanas. Los estudios sobre las diversas actividades biológicas de las especies Miconia han presentando resultados promisorios. Varios autores han evaluado extractos de estas plantas contra T. cruzi, comprobando que estos exiben actividad tripanocida significativa. La presencia de ácidos ursólico y oleanólico determinan la actividad biológica.

A doença de Chagas é uma doença negligenciada causada pelo protozoário Trypanosoma cruzi e ainda permanece como um relevante problema de saúde pública na América Latina. O medicamento disponível para o tratamento clínico no Brasil é o benzonidazol, que é efetivo contra as formas circulantes do parasita na fase aguda da doença, entretanto, sua eficácia na fase crónica permanece discutível. A pesquisa por novas drogas que possam ser utilizadas no tratamento dessa doença é urgentemente necessária e as fontes naturais com os seus metabólitos secundários diversificados, podem desempenhar um papel extremamente importante. Miconia é um dos maiores géneros pertencente à família Melastomataceae incluindo cerca de 1.000 espécies e, no Brasil existem cerca de 250 espécies em florestas e savanas. Estudos realizados com o objetivo de descrever as diferentes atividades biológicas de espécies de Miconia têm apresentado resultados promissores. Vários autores têm avaliado os extratos dessas plantas contra as formas tripomastigotas sanguíneas de T. cruzi (in vitro) e verificado que essas amostras exibem atvidade tripanocida significativa. A presença dos triterpenos ácidos ursólico oleanólico está relacionada com esta atividade biológica.

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 ·â€ŠmL⁻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 ·â€ŠmL⁻¹, and an IC50 of 326.5 µg ·â€ŠmL⁻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.

In vivo analgesic activity, toxicity and phytochemical screening of the hydroalcoholic extract from the leaves of Psidium cattleianum Sabine.

ETHNOPHARMACOLOGICAL RELEVANCE: Psidium cattleianum Sabine is extensively used in Brazilian traditional medicine to treat several diseases including painful disorders. Aim of the study to investigate the toxicity and the possible analgesic activities of the hydroalcoholic extract from the leaves of Psidium cattleianum Sabine (ELPCS), to support its use in folk medicine. To screen the major phytochemical constituents of this extract and evaluate their antioxidant activity. MATERIALS AND METHODS: ELPCS was assessed for its antioxidant activity using the DPPH model. Its analgesic activity was examined using mouse models of acetic acid-induced writhing and hot plate paw licking models. The major phytochemical constituents of the extract were screened; their toxicity on LLC-MK2 mammalian cells was evaluated. RESULTS: ELPCS exhibited significant peripheral analgesic activity at doses of 60, 80, 100, 200 and 400mg/kg in mice, but it did not display central analgesic activity and not was toxic to LLC-MK2 cell (LD50>400 µg/mL). The extract exhibited free radical scavenging activity as evidenced by IC50 values (15.9 µg/mL) obtained by the DPPH method. Phytochemical screening detected flavonoids, saponins, cardiac glycosides, anthraquinones, and tannins. CONCLUSIONS: The results of the experimental studies proved the analgesic activity of ELPCS and supported the traditional use of this plant.

In vivo activity of ursolic and oleanolic acids during the acute phase of Trypanosoma cruzi infection.

Reduction in the parasitemic levels of the Y strain of Trypanosoma cruzi in mice treated with oral or intraperitoneal ursolic (UA) and oleanolic (OA) acids was evaluated during the acute phase of Chagas' disease. Oral administration of UA and OA (50mg/kg/day) provided the most significant reduction in the parasitemic peak, while intraperitoneal administration of UA and OA did not significantly affect the biological activity of the Y strain of T. cruzi. Interleukin levels in mice treated by the intraperitoneal route were compared to untreated chagasic mice. Reduced γ-IFN levels and enhanced IL-10 concentrations potentially explain the exacerbated parasitemia. Our data suggests an immunosuppressive effect for UA and OA, which could interfere with host control of parasitemia. Optimal results were achieved with oral administration. This observation may be explained by the low intestinal absorption of UA and OA, could cause a reduced immune response and promote parasite control. Taken together, these data demonstrate that triterpenes could be interesting compounds to develop therapeutically for the treatment of Chagas' disease.

Evaluation of the in vivo therapeutic properties of (-)-cubebin and (-)-hinokinin against Trypanosoma cruzi.

Even though the Chagas' disease, caused by the protozoan Trypanosoma cruzi, was described 100years ago by Carlos Chagas, it still represents a major public health concern and is found in 18 developing countries in South and Central America. In Brazil, Benznidazole (Rochagan) is the only drug with trypanocidal activity available in the market, despite its several side effects and limited efficacy in the chronic phase of the infection. In view of the need for new substances displaying biological activity against T. cruzi, there has been growing interest in research toward the attainment of compounds capable of acting on the parasite while being devoid of serious side effects. In this context, this study aims to evaluate the in vivo therapeutic activity of dibenzylbutyrolactone lignans (-)-cubebin and (-)-hinokinin during the acute phase of infection by T. cruzi. As a study criterion, animals with acute parasitemia were investigated by tissue morphometric analysis. There was significant parasitemia reduction in the groups of animals treated with (-)-cubebin or (-)-hinokin oral administration, compared to the negative control. Values close to those of the uninfected control were found in the groups treated with (-)-cubebin and (-)-hinokinin via kariometry, showing that there was positive cellular response compared to the infected control.

In vivo infection by Trypanosoma cruzi: a morphometric study of tissue changes in mice.

Nifurtimox and benznidazole, medications currently used for the treatment of the Chagas disease, are not always successful. We determine whether (-)-cubebin and (-)-hinokinin could be used as alternative drugs for the treatment of parasitic infections by Trypanosoma cruzi. To this end, male BALB/c mice were treated with both drugs, and the nuclear parameters (largest diameter, smallest diameter, and perimeter) were determined from slides prepared from the spleen, liver, and heart. The cytotoxicity of the substances was determined after 24-h treatment. Results revealed increased cell nuclei in untreated infected animals as compared to uninfected mice. The values obtained for infected animals treated with (-)-cubebin and (-)-hinokinin were close to those observed for uninfected mice. For the spleen, perimeter values of 10.85 µm (p < 0.01) and 10.90 µm (p < 0.05) were obtained for mice treated with (-)-cubebin 50 mg/kg and (-)-hinokinin 20 mg/kg, respectively, whereas untreated infected animals furnished a perimeter of 11.76 µm. As for the liver, perimeter values of 19.06 µm (p < 0.01) and 18.61 µm (p < 0.001) were achieved for mice treated with (-)-cubebin 50 mg/kg and (-)-hinokinin 20 mg/kg, respectively, whereas a perimeter of 18.54 µm was obtained for untreated infected animals. The cytotoxicity assays demonstrated that (-)-cubebin and (-)-hinokinin does not display toxicity. Therefore, (-)-cubebin and (-)-hinokinin are promising therapeutic agents and could be used in future clinical studies concerning treatment of the Chagas disease. Even if the karyometry is not used frequently, it can complement other methods, such as PCR, and furthermore, it is a simple method which is easily possible to analyze the activity of substances in the tissues of treated infected animals compared to uninfected animals.

In vitro efficacy of the essential oil of Piper cubeba L. (Piperaceae) against Schistosoma mansoni.

In this paper, cercariae, schistosomula, and adult Schistosoma mansoni worms were incubated in vitro with the essential oil of Piper cubeba (PC-EO) at concentrations from 12.5 to 200 µg/mL, and the viability was evaluated using an inverted microscopy. The effects of PC-EO at 100 and 200 µg/mL on the stages of S. mansoni were similar to those of the positive control (PZQ at 12.5 µg/mL), with total absence of mobility after 120 h. However, at concentrations from 12.5 to 50 µg/mL, PC-EO caused a reduction in the viability of cercariae and schistosomula when compared with the negative control groups (RPMI 1640 or dechlorinated water) or (RPMI 1640 + 0.1% DMSO or dechlorinated water + 0.1% DMSO). On the other hand, adult S. mansoni worms remained normally active when incubated with PC-EO at concentrations of 12.5 and 25 µg/mL, and their viabilities were similar to those of the negative control groups. In addition, at concentrations ranging from 50 to 200 µg/mL, separation of all the coupled adult worms was observed after 24 h of incubation, which is related to the fact of the reduction in egg production at this concentration. The main chemical constituents of PC-EO were identified by gas chromatography-mass spectrometry as being sabinene (19.99%), eucalyptol (11.87%), 4-terpineol (6.36%), ß-pinene (5.81%), camphor (5.61%), and δ-3-carene (5.34%). The cytotoxicity of the PC-EO was determined, and a significant cytotoxicity was only obtained in the concentration of 200 µg/mL after 24 h treatment. The results suggest that PC-EO possesses an effect against cercariae, schistosomula, and adult worms of the S. mansoni.

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 beta-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.

Trypanocidal activity and acute toxicity assessment of triterpene acids.

The present study evaluates the in vitro and in vivo trypanocidal activity of ursolic acid and oleanolic acid against the Bolivia strain of Trypanosoma cruzi. Their acute toxicity is also assessed on the basis of median lethal dose (DL50) determination and quantification of biochemical parameters. Ursolic acid is the most active compound in vitro, furnishing IC50 of 25.5 microM and displaying 77% of trypomastigote lysis at a concentration of 128 microM. In agreement with in vitro assays, the results obtained for the in vivo assay reveals that ursolic acid (at a dose of 20 mg/Kg/day) provides the most significant reduction in the number of parasites at the parasitemic peak. Results concerning the LD50 assay and the biochemical parameters evaluated in the present study demonstrate that these substances can be safely used on an experimental basis.