Exploring antioxidant and α-glucosidase inhibition in Eugenia L. extracts: a comprehensive phytochemical study

This study analysed extracts obtained from the leaves of Eugenia uniflora, E. involucrata, and E. myrcianthes to determine their chemical composition, antioxidative properties, and α-glucosidase inhibitory capacity. By using liquid chromatography with a diode array detector, we identified chlorogenic acids, flavonoids, tannins, proanthocyanidins, saponins, and triterpenes in the extracts. The antioxidant activities of the extracts were found to be directly related to their total phenolic, flavonoid content and enzyme inhibition. The E. uniflora aqueous extract showed significant inhibition of α-glucosidase (IC50 0.98 µg mL-1), indicating its potential as a non-competitive inhibitor for managing Diabetes Mellitus. This study contributes to the existing knowledge on the chemical and biological aspects of Eugenia genus.

Ateroprotective effects of Plinia cauliflora in. New Zealand rabbits: beyond the lipid-lowering effect

Introduction: Plinia cauliflora [Mart.] Kausel (Myrtaceae), popularly known as "jabuticaba," is a fruit species native to Brazil. Despite extensive widespread usage, its antiatherosclerotic properties' impact remains unknown. Thus, the present study aimed to investigate the cardioprotective effects of a preparation obtained from the fruit peels of P. cauliflora (EEPC). Methods: Male New Zealand rabbits received a 1% cholesterol-supplemented diet for 60 days. On the thirtieth day, the animals were divided into five experimental groups and received, once a day, by the oral route, the EEPC (10, 30, and 100 mg/kg), simvastatin (2.5 mg/kg), or vehicle for 30 days. At the end of the experimental period, peripheral blood and arterial branch samples were collected. The levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), malondialdehyde (MDA), nitrotyrosine (NT), nitrite, interleukin 1 beta (IL-1b), interleukin 6 (IL-6), soluble inter-cellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1) levels were measured. Moreover, the catalase and superoxide dismutase levels were measured on the arterial samples. Histopathological analysis and arterial morphometry were also performed. Results and discussion: The oral administration of ESEG significantly lowered the levels of lipids in rabbits that were fed a CRD diet. This treatment also adjusted the protective system against oxidation in the arteries by decreasing the oxidation of lipids and proteins. Additionally, the levels of IL-1b, IL-6, sICAM-1, and sVCAM-1 in the bloodstream decreased significantly, and this was accompanied by a reduction of atherosclerotic lesions in all branches of the arteries. The findings suggest that EEPC may be a possible option for additional management of atherosclerosis.

Cardioprotective Effects of Solidago microglossa DC. in Nicotine-Treated Hypertensive Rats

Solidago microglossa DC. (Asteraceae), "arnica brasileira," is a Brazilian species popularly used to treat hypertension or renal ailments. This study investigated the cardioprotective effects of standardized S. microglossa extract (EESM) in nicotine-treated spontaneously hypertensive rats (SHRs). Moreover, the molecular mechanisms involved in the cardiovascular effects were also investigated. The acute toxicity was evaluated in female Wistar rats. Afterwards, six-month-old male spontaneously hypertensive rats received the EESM (14, 28, and 56 mg/kg), hydrochlorothiazide (25 mg/kg), and vehicle (filtered water; 0.1 mL/100 g) once daily for 28 days. All treatments were associated with 1.8 mg/kg of nicotine. At the end of the experimental period, the renal function, electrocardiographic profile, blood pressure, ventricular function, biochemical parameter, and mesenteric vascular bed reactivity were evaluated. Relative organ weights and cardiac morphometry were also investigated. Nicotine treatment in 6-month-old SHRs induced a significant reduction in renal function, with reduced urinary volume and lower renal elimination of sodium and creatinine. In addition, serum markers of the redox state and blood pressure levels remained significantly elevated, contributing to changes in vascular reactivity and left ventricular hypertrophy associated with reduced ventricular function. After 28 days of treatment, we found that the highest dose of EESM could mitigate all renal and cardiovascular changes developed by the nicotine-treated hypertensive rats. This study presented EESM as a possible cardioprotective drug that prevents cardiovascular dysfunctions in nicotine-treated hypertensive rats. Our data suggest EESM as a potential adjuvant therapy when cardioprotective effects are required.

Self-Curing Glass Ionomer Cement Covered by Photopolymerizable Adhesive for Protection of Mucoperiosteal or Gingival Flap Sutures in Canine Oral Surgery

Periodontal disease is one of the main affections of the oral cavity of dogs. Its main complication is the formation of periapical abscess, which, when affecting the maxillary canine teeth, can lead to the formation of oronasal fistulae. The objective of this study was to evaluate the efficiency of self-curing glass ionomer cement, covered by photopolymerizable adhesive, as a protective element for mucoperiosteal or gingival flap sutures in oral surgery of dogs. We studied 15 dogs from the clinical routine of the dental service of a teaching veterinary hospital, which needed oral surgeries to correct oronasal fistulae, defects or oral cavity communications, regardless of the causal agent. Group one (G1) was composed of seven animals that presented oronasal fistulae after the extraction of maxillary canine teeth compromised by severe periodontal disease. These fistulae were reduced by the double-mucoperiosteal-flap technique, 15 days after the dental extraction. Group two (G2) was composed of five other dogs that presented oronasal fistulae after the extraction of maxillary canine teeth compromised by severe periodontal disease. In this group, the fistulae were reduced by the single-flap technique, immediately after the dental extraction. Group three (G3) was composed of three animals, two of which presented oronasal fistulae due to maxillary fracture and the third one after excision of oral neoplasia. In all groups, simple interrupted sutures were used with 3.0 nylon, and a thin layer of self-curing glass ionomer cement was applied immediately over the operated area. After cement's settling time, a thin layer of photopolymerizable adhesive was applied to the already polymerized cement. In G1, the protective cement was removed on average at 15 (±2) postoperative days, in G2 at 6 (±1) days and in G3 at 11 (±9) days. In the postoperative period, the animals received antibiotics and anti-inflammatory drugs, and they received their usual dry dog food diet. No Elizabethan collar or any other protective measure was used for suturing or the surgical wound. The result was healing of 100% of the oronasal fistulae, without suture dehiscence or the need for new surgical interventions. Thus, it was concluded that the use of self-curing glass ionomer cement covered by photopolymerizable adhesive was fully satisfactory, providing protection of sutures and surgical wounds and showing the potential for routine use in oral surgery in dogs.

Extraction Methods, Chemical Characterization, and In Vitro Biological Activities of Plinia cauliflora (Mart.) Kausel Peels

Plinia cauliflora (Mart.) Kausel, popularly known as jabuticaba, possesses bioactive compounds such as flavonoids, tannins, and phenolic acids, known for their antioxidant, antibacterial, wound healing, and cardioprotective effects. Therefore, this study aimed to standardize the P. cauliflora fruit peel extraction method, maximize phenolic constituents, and evaluate their antioxidative and antimicrobial effects. Various extraction methods, including vortex extraction with and without precipitation at 25, 40, and 80 °C, and infusion extraction with and without precipitation, were performed using a completely randomized design. Extraction without precipitation (E - P) showed the highest yield (57.9%). However, the precipitated extraction (E + P) method displayed a yield of 45.9%, higher levels of phenolic derivatives, and enhanced antioxidant capacity. Major compounds, such as D-psicose, D-glucose, and citric acid, were identified through gas chromatography-mass spectrometry (GC-MS) analysis. Ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis identified citric acid, hexose, flavonoids, tannins, and quercetin as the major compounds in the extracts. Furthermore, the extracts exhibited inhibitory effects against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli bacteria. In conclusion, the E + P method efficiently obtained extracts with high content of bioactive compounds showing antioxidant and antimicrobial capacities with potential application as a dietary supplement.

Bioprospecting a Film-Forming System Loaded with Eugenia uniflora L. and Tropaeolum majus L. Leaf Extracts for Topical Application in Treating Skin Lesions

Natural products can be used as complements or as alternatives to synthetic drugs. Eugenia uniflora and Tropaeolum majus are natives of Brazil and have antimicrobial, anti-inflammatory, and antioxidant activities. This study aimed to develop a film-forming system (FFS) loaded with plant extracts with the potential for treating microbial infections. E. uniflora and T. majus leaf extracts were prepared and characterized, and the individual and combined antioxidant and antimicrobial activities were evaluated. The FFS was developed with different concentrations of polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) and analyzed for physicochemical characteristics. The combination of extracts showed a superior antioxidant effect compared to the individual extracts, justifying the use of the blend. FFS prepared with 4.5% PVA, 4.5% PVP, 7.81% E. uniflora extract, and 3.90% T. majus extract was adhesive, lacked scale formation, presented good malleability, and had a suitable pH for topical application. In addition, the viscosity at rest was satisfactory for maintaining stability; water solubility was adequate; skin permeation was low; and the antimicrobial effect was superior to that of the individual extracts. Therefore, the developed FFS is promising for the differentiated treatment of skin lesions through topical application.

Natural Products as Modulators of Mitochondrial Dysfunctions Associated with Cardiovascular Diseases: Advances and Opportunities

The mitochondria have an important role in modulating cell cycle progression, cell survival, and apoptosis. In the adult heart, the cardiac mitochondria have a unique spatial arrangement and occupy nearly one-third the volume of a cardiomyocyte, being highly efficient for converting the products of glucose or fatty acid metabolism into adenosine triphosphate (ATP). In cardiomyocytes, the decline of mitochondrial function reduces ATP generation and increases the production of reactive oxygen species, which generates impaired heart function. This is because mitochondria play a key role in maintaining cytosolic calcium concentration and modulation of muscle contraction, as ATP is required to dissociate actin from myosin. Beyond that, mitochondria have a significant role in cardiomyocyte apoptosis because it is evident that patients who have cardiovascular diseases (CVDs) have increased mitochondrial DNA damage to the heart and aorta. Many studies have shown that natural products have mitochondria-modulating effects in cardiac diseases, determining them as potential candidates for new medicines. This review outlines the leading plant secondary metabolites and natural compounds derived from microorganisms as modulators of mitochondrial dysfunctions associated with CVDs.

Bacopa monnieri in Patients with Parkinson's Disease: A Pilot Study

Bacopa monnieri (L.) Wettst. could be of interest in the control of symptoms of Parkinson's disease, but clinical evidence of its efficacy is lacking. This clinical trial assessed the effects of an extract of B. monnieri on parameters that are related to Parkinson's diseases. Twenty volunteers with Parkinson's disease were recruited for a primary, interventional, controlled, parallel, double-blind clinical study. The volunteers were assigned to treatment with either a commercial B. monnieri extract (225 or 450 mg/day) or placebo. The Parkinson's Disease Quality-of-Life (PDQL) questionnaire was applied, and motor activity was assessed before treatment and 30, 60, and 90 days after treatment with the B. monnieri extract or placebo. Characteristics such as age, body weight, and height were also collected. No differences in parkinsonian and systemic symptoms, emotional function, or social function were observed between. The delta percent (Δ%) showed time-dependent improvements in emotional function with B. monnieri treatment at the daily dose of 450 mg. A strong correlation was found between quality of life and motor outcomes at baseline and 30 days of treatment with B. monnieri, and a moderate correlation for 60 and 90 days of treatment with B. monnieri when compared with baseline time. A moderate correlation was found between motor outcomes and Hoehn and Yahr stages at baseline. Our results suggest that B. monnieri extract can improve emotional function in Parkinson's disease patients, but further clinical trials are needed to confirm this possibility.

Evidence of the Cardioprotective Effects of Aloysia polystachya in Isoproterenol-Induced Myocardial Infarction in Rats

Aloysia polystachya is a plant species that is widely used in Brazilian folk medicine for the treatment of different disorders that affect the cardiovascular system. The aim of the study was to investigate the cardioprotective effects of an ethanol-soluble fraction of A. polystachya (ESAP) on isoproterenol-induced myocardial infarction in rats. Different groups of rats (n = 8) were orally treated with ESAP (30, 100, and 300 mg/kg), carvedilol (10 mg/kg), or vehicle (filtered water; 1 mL/100 g) for 7 days. Naive rats received no treatment. On the morning of day 6, acute myocardial infarction was induced by the acute oral administration of isoproterenol (100 mg/kg). On the morning of day 8, all rats underwent electrocardiography and transthoracic echocardiography. Blood samples were then collected, and serum levels of creatine kinase-MB fraction (CK-MB) and cardiac troponin T (cTNT) were quantified. ESAP significantly reduced electrocardiographic changes, improved the ventricular ejection fraction, and reduced serum levels of CK-MB and cTNT in infarcted rats. The cardioprotective effects of ESAP could be exploited as an effective tool against isoproterenol-induced myocardial infarction in rats.

Small conductance calcium-activated potassium channels and nitric oxide/cGMP pathway mediate cardioprotective effects of Croton urucurana Baill. In hypertensive rats

ETHNOPHARMACOLOGICAL RELEVANCE

Croton urucurana Baill. (Euphorbiaceae), popularly known as 'sangue de dragão' is a Brazilian species widely used in traditional medicine for cardiovascular ailments.

AIM

To investigate the cardiovascular effects of the C. urucurana extract in spontaneously hypertensive rats (SHRs).

MATERIALS AND METHODS

Leaves from C. urucurana were collected and morphoanatomically characterized. The ethanol-soluble fraction (ESCU) was obtained and analyzed by LC-DAD-MS. Using female Wistar rats we investigated the acute toxicity of ESCU. Then, SHRs (six months old) received vehicle, hydrochlorothiazide (25 mg/kg), or ESCU (30, 100, 300 mg/kg) for 28 days. At the beginning and at the end of treatments, urine samples were obtained to assess renal function. At the end of the trial period, the blood pressure, mesenteric vascular beds (MVBs) reactivity, and electrocardiographic profile were evaluated. Serum angiotensin-converting enzyme activity, as well as urea, creatinine, sodium, potassium, nitrite, malondialdehyde, nitrotyrosine, and aldosterone levels were determined. Relative organ weights and histopathological analysis were performed. Finally, the cardiac function on a Langendorff system, as well as the molecular mechanisms involved in the vasodilator effects of ESCU in MVBs were also investigated.

RESULTS

The compounds annotated from ESCU by LC-DAD-MS included mainly phenylpropanoid derivatives, alkaloids, O-glycosylated megastigmanes, glycosylated flavonoids, flavan-3-ols, and others, such as quercetin O-deoxyhexosyl-hexoside, magnoflorine, reticuline, and taspine. None of the animals showed any signs of toxicity. Male SHRs treated only with the vehicle showed important cardiovascular changes, including a reduction in renal function, increase in serum oxidative stress, and hemodynamic, electrocardiographic, and morphological changes typical of hypertensive disease. Moreover, parameters of cardiac function, including left ventricular developed pressure, peak rate of contraction, peak rate of relaxation, and the rate pressure product were significantly altered, showing a significant impairment of ventricular function. All ESCU-doses presented a significant cardioprotective effect in SHRs rats. The 28-day treatment normalized the hemodynamic, electrocardiographic, morphological, and renal impairments, as well as reversed the changes in ventricular function induced by hypertension. In MVBs with an intact endothelium, ESCU (0.1, 0.3, and 1 mg) dose-dependently induced vasodilation. Endothelium removal or the inhibition of nitric oxide synthase prevented the vasodilatory effect of ESCU. Perfusion with a physiological saline solution that contained KCl, tetraethylammonium, or apamin also abolished the vasodilatory effect of ESCU.

CONCLUSION

Prolonged ESCU-treatment showed significant cardioprotective effects in SHRs. Moreover, the data showed the role of nitric oxide and calcium-activated small conductance potassium channels in the cardiovascular effects of ESCU.

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Cardioprotective effects of Talinum paniculatum (Jacq.) Gaertn. in doxorubicin-induced cardiotoxicity in hypertensive rats

ETHNOPHARMACOLOGICAL RELEVANCE

Talinum paniculatum (Jacq.) Gaertn. (Talinaceae) is a medicinal species that is widely distributed throughout Brazil. Popularly known as "major-gomes," the species is used in folk medicine for the treatment of cardiovascular disorders.

AIM OF THE STUDY

To evaluate the effect of an ethanolic extract of T. paniculatum (EETP) in rats with renovascular hypertension and heart failure and determine its chemical composition.

MATERIALS AND METHODS

First, EETP was obtained, and its chemical profile was analyzed by LC-DAD-MS. The acute toxicity was evaluated in female Wistar rats. The model of renovascular hypertension was established in male Wistar rats by combining the Goldblatt 2K1C method and intraperitoneal doxorubicin administration for 6 weeks. The animals were then treated daily with EETP (30, 100, and 300 mg/kg) or metoprolol (25 mg/kg) by gavage for 28 days. The negative control group was treated with vehicle (filtered water). The sham group consisted of animals that were not subjected to 2K1C or cardiotoxicity and were treated with vehicle. Renal function was evaluated on days 1, 14, and 28. At the end of treatment, the electrocardiographic profile, blood pressure, and mesenteric vascular reactivity were investigated. Serum urea, creatinine, angiotensin converting enzyme, nitrotyrosine, malondialdehyde, nitrite, aldosterone, and sodium and potassium levels were measured. The heart, aorta artery, liver, and right kidney were collected, weighed, and processed for histopathological analysis. Cardiac chambers also underwent morphometric analysis.

RESULTS

No signs of toxicity were observed in female Wistar rats. Thirty-two compounds were annotated from EETP, including flavonoids, chlorogenic acids, and saponins. EETP treatment resulted in a significant cardiorenal-protective response, normalizing electrocardiographic and hemodynamic alterations, and preventing ventricle remodeling. These effects were associated with serum antioxidant activity and angiotensin-converting enzyme (ACE) inhibition.

CONCLUSION

The present study demonstrated that EETP may exert cardioprotective effects through serum antioxidant activity and ACE inhibition, preventing alterations of hemodynamic and endothelial function, and reducing damage to cardiac structure. Thus, EETP, especially at the 100 and 300 mg/kg doses, may be useful for preventing doxorubicin-induced cardiotoxicity in hypertensive patients.

Therapeutic Feasibility of the Natural Products in the Heart Complaints: An Overview

Heart pain is the most frequent complaint leading patients to seek medical help. Functional heart symptoms, especially chest pain, are prevalent and, according to the International Classification of Diseases (ICD-10), are described as "somatoform autonomous functional disorders of the cardiovascular system." The problem lies in the fact that pain does not always have a somatic background, that is, it may be related to crucial underlying heart disease. The population does not know how to differentiate somatic pain from significant ischemic symptoms, and based on the patient's complaints, traditional medicine ends up treating other underlying cardiac diseases. Many unsuccessful unconventional therapies have been proposed in recent years, including herbal medicines that seek to disrupt the disease's pathogenesis. The present review summarizes research carried out in the last 5 years on natural products' heart complaints, including myocardial ischemia, arrhythmia, and heart failure. Several herbal medicines may be used as a replacement or complementary treatment strategy. A total of 17 medicinal plants have shown promising results in preclinical studies. However, human clinical trials are scarce; only two have been presented. Generally, the data are bland, and many issues have been raised about herbal therapies' safety, efficacy, and mode of action. Besides, relevant clinical trials, future perspectives, and possible clinical applications are discussed.

Leptospira spp. in Naturally Infected Dairy Cow from a Brazilian Border Region

Leptospirosis is an important infectious disease, which can generate large economic losses, especially in the dairy herd. The pathogen that causes this disease may have its entry in Brazilian herds facilitated by the existence of a large extension of land borders. Therefore, the objective of this work was to investigate the presence of DNA and antibodies against Leptospira spp. in samples of vaginal mucus and serum from naturally infected bovine females from small rural dairy farms in a border region. Blood and vaginal mucus samples were collected from 70 Holstein cows, from small rural dairy farms between October 2017 and June 2018. The inclusion criteria for dairy cattle of any breed were aged over 2 years, not vaccinated against leptospirosis, and presenting a history of any reproductive problem such as abortion, stillbirth, repetition of heat, absence of heat, and lack of conception. Blood was collected by puncturing the coccygeal vein; for the collection of vaginal mucus, it was necessary to use a tampon with an applicator. For the detection of anti-Leptospira spp. antibodies, the sera were submitted to microscopic agglutination test (MAT) and, for DNA detection, the vaginal mucus was submitted to the PCR technique. Among the 70 cows, 42.86% had reagents in MAT and the most likely serovar was Wolffi (43.47%). In 74.28% of the vaginal mucus samples, it was possible to amplify the Leptospira spp. DNA. The results of this work show the presence of Leptospira spp. antibodies and DNA in samples of serum and vaginal mucus from naturally infected bovine females from small rural dairy farms in a border region (Brazil × Paraguay). These results demonstrate the importance of considering bovine females as potential vaginal carriers of Leptospira spp. Thus, it highlights the importance of further studies to better understanding of this issue, in addition to carrying out molecular and serological tests, to monitor the infection and further characterize epidemiological studies of leptospirosis in herds from regions that face this international frontier challenge.

Ethnopharmacological investigation of the cardiovascular effects of the ethanol-soluble fraction of Aloysia polystachya (Griseb.) Moldenke leaves in spontaneously hypertensive rats

ETHNOPHARMACOLOGICAL RELEVANCE

Aloysia polystachya (Griseb) Moldenke (Verbenaceae), popularly known as "burrito", is a South American species widely prescribed by local Brazilian healers for the treatment of cardiovascular diseases. However, its antihypertensive and cardioprotective effects are still unknown.

AIM

To evaluate the role of the ethanol-soluble fraction of A. polystachya leaves (ESAP) against hypertension in spontaneously hypertensive rats (SHRs), as well as its safety, morphoanatomical and phytochemical aspects.

MATERIALS AND METHODS

First, the leaves and stems of A. polystachya were analyzed by optical and scanning electron microscopy in order to provide anatomical data for quality control. Then, ESAP was obtained and its chemical profile was analyzed by LC-DAD-MS. In addition, the cytotoxic and acute toxicity potential of ESAP were evaluated in six cell lines and in female Wistar rats, respectively. Next, female spontaneously hypertensive rats (SHRs) received ESAP (30, 100, 300 mg/kg), hydrochlorothiazide (25 mg/kg), or vehicle once daily for 28 days. Weekly kidney function was monitored by analyzing urinary parameters. At the end of the 28-day treatment, the electrocardiographic profile, blood pressure, and renal and mesenteric vascular reactivity were evaluated. Relative organ (heart, kidney, and liver) weights and biochemical parameters were also evaluated. Finally, the heart, kidneys, and aorta were collected for determination of the tissue redox state, cardiac morphometry, and histopathological analysis.

RESULTS

The chemical profile of ESAP was composed by organic acids, a nucleoside, methoxylated flavones and glycosylated compounds including phenolic acids, phenylpropanoids, iridoids and monoterpenes. No signs of toxicity were observed in all cell's lines nor in female Wistar rats submitted to this trial. All SHRs from the negative control group presented a reduction in renal function, alterations in the renal and mesenteric vascular reactivity, and electrocardiographic and morphometric changes typical of ventricular hypertrophy. Oral prolonged ESAP-administration in SHRs was able to reverse renal, electrocardiographic and hemodynamic changes induced by hypertension. Moreover, ESAP-treatment was able to modulate the vascular and renal arterial reactivity and tissue redox state. The aforementioned data were accompanied by reduction of cardiac hypertrophy.

CONCLUSION

In this study, we present important anatomical and phytochemical data that contributed to the correct identification and quality control of A. polystachya. In addition, we have shown that ESAP is safe after acute administration and present significant cardioprotective effects (at 30, 100, and 300 mg/kg doses) in SHRs after prolonged treatment.

Urban Horses As Environmental Bioindicators for Leishmaniasis

The presence of DNA and anti-Leishmania spp. antibodies in the serum of 112 healthy horses was investigated by evaluating the physical examination, from a rural society located in the north central region of Paraná. The antigens of Leishmania amazonensis, Leishmania braziliensis, and Leishmania infantum were used to perform the indirect enzyme-linked immunosorbent assay, where it was possible to detect the reaction in 27.67% of the samples. These were also subjected to the real-time quantitative PCR, which confirmed the presence of Leishmania spp. DNA in 67.34% of the tested samples. The results show that the tested animals were previously exposed to the protozoan. Thus, these animals can be considered environmental bioindicators of the presence of Leishmania spp. at the study site. The material used in this study (serum), although not ideal, proved to be effective and less invasive. Taking into account the importance of the disease, the absence of more in-depth information on the species, the high zootechnical value of these animals, and their strictly close contact with the urban area and the human species, it is essential that further studies are carried out to elucidate the epidemiological profile of them in the face of the disease, as well as the possibility of them acting not only as hosts but also as reservoirs.

Ethnomedicinal Plants Used for the Treatment of Cardiovascular Diseases by Healers in the Southwestern State of Paraná, Brazil, and Their Validation Based on Scientific Pharmacological Data

Cardiovascular diseases are responsible for high morbidity and mortality rates worldwide. Among treatment options, medicinal plants are frequently used, especially in developing countries, such as Brazil. Despite social development that has been observed in the last decades, the use of medicinal plants is still driven by popular knowledge, especially by healers. The present study sought to identify medicinal species that are used for the treatment of cardiovascular diseases by healers in the microregion of Francisco Beltrão, Paraná, Brazil. The snowball technique was used to select informants, and data were collected through interviews. The research was performed in two stages: (1) a structured interview and (2) the collection and botanical identification of the species that were mentioned by the healers. Medicinal plants were classified into the following categories of cardiovascular agents: hypotensive and antihypertensive agents, lipid-lowering agents, diuretic agents, and cardiotonic agents. To analyze the data, the frequency was determined, Spearman correlations were calculated, and the informant consensus factor (ICF) and use value were obtained. Some characteristics, such as female gender and old age, were associated with knowledge about medicinal plants. Overall, 77 different species and 149 medicinal uses were cited by the healers. With regard to categories of use, the highest number of species was found among lipid-lowering plants, and the highest ICF was found for species that are used as cardiotonics. Moreover, a literature review indicated that among the cited species, several still lack studies that have proven their effects on the cardiovascular system. The traditional use of medicinal plants for the treatment of cardiovascular diseases is broad in the study regions. The present results are important for clarifying popular knowledge in this region and providing a framework for selecting species with potential for the development of new pharmacological studies.

From general toxicology to DNA disruption: A safety assessment of Plinia cauliflora (Mart.) Kausel

ETHNOPHARMACOLOGICAL RELEVANCE

Plinia cauliflora (Mart.) Kausel (Myrtaceae) is popularly known as "jaboticaba" or "jaboticaba". The fruit is appreciated for both fresh consumption and the manufacture of jelly, juice, ice cream, fermented beverages, and liqueurs. The more widespread traditional use of the plant involves the treatment of diarrhea, which utilizes all parts of the plant, including the fruit peels.

AIM OF THE STUDY

We sought to elucidate possible risks of the administration of an ethanol-soluble fraction that was obtained from an infusion of P. cauliflora fruit peels (SEIPC). We performed a series of experiments to evaluate possible toxicity, in which we administered SEIPC orally both acutely and repeatedly for 28 days. We also evaluated possible endocrine-disruptive and genotoxic effects in eukaryotic cells. The possible mutagenic activity of SEIPC was evaluated using reverse mutation (Ames) assays.

MATERIALS AND METHODS

SEIPC was produced and chemically characterized by LC-DAD-MS. Acute toxicity and behavioral and physiological alterations were evaluated in the modified Irwin test. Respiratory rate, arterial blood gas, electrocardiography, respiratory rate, heart rate, and blood pressure were evaluated, and hematological, biochemical, and histopathological analyses were performed after 28 days of oral treatment. The comet assay, mammalian erythrocyte micronucleus test, uterotrophic test, Hershberger bioassay, and AMES test were performed using appropriate protocols.

RESULTS

From SEIPC, ellagic acid and derivatives, flavonols and anthocyanidins, as well as citric acid and gallic acid, were annotated by LC-DAD-MS. We did not observed any significant toxic effects after acute or prolonged SEIPC treatment. No endocrine-disruptive or mutagenic effects were observed.

CONCLUSIONS

The present study found that SEIPC did not cause any significant alterations of various corporeal systems, including cardiac electrical activity, body temperature, respiratory rate, and arterial pressure. No alterations of biochemical, hematological, or blood gas parameters were observed. SEIPC did not cause any perturbations of the endocrine system or mutagenic, cytotoxic, or genotoxic effects. These findings substantiate the safe clinical use of P. cauliflora.

Cardioprotective effects of Plinia cauliflora (Mart.) Kausel in a rabbit model of doxorubicin-induced heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

In Brazil, the fruit of a native species that is popularly known as "jabuticaba" (Plinia cauliflora [Mart.] Kausel) is widely consumed fresh or used for the production of liqueur, juice, and jelly. In Brazilian folk medicine, this species is used to treat asthma, throat inflammation, and gastrointestinal and cardiovascular disturbances. However, no previous studies have reported its cardioprotective effects.

AIM

To evaluate the possible cardioprotective effects of a hydroethanolic extract of Plinia cauliflora (EEPC) in female rabbits in a model of doxorubicin-induced heart failure.

MATERIAL AND METHODS

EEPC was obtained and fractionated by solid phase extraction, and its constituents were determined by liquid chromatography coupled to diode array detector and mass spectrometry (LC-DAD-MS). Thirty female New Zealand rabbits received doxorubicin administration for 6 weeks to induce heart failure. EEPC was orally administered at doses of 75 and 150 mg/kg daily for 42 days. Enalapril (5 mg/kg) was used as a reference cardioprotective drug. At the end of the experimental period, blood pressure and heart rate were recorded. Serum parameters, including lipid profile, troponin, creatinine, nitrotyrosine, malondialdehyde, nitrite, and brain natriuretic peptide, were measured. The electrocardiographic profile and renal vascular reactivity were evaluated. Cardiac histopathology and ventricular morphometry were performed, and the tissue enzymatic antioxidant system was investigated.

RESULTS

A total of 37 compounds were detected in EEPC, including organic acids, phenolic acid derivatives, flavonoids, anthocyanins, and hydrolysable tannins (gallotannins and ellagitannins). EEPC treatment induced a cardiorenal protective response, prevented hemodynamic and functional alterations, and prevented ventricle remodeling. These effects were associated with the normalization of creatinine and brain natriuretic peptide levels and modulation of the tecidual antioxidant defense system.

CONCLUSION

The present study demonstrated that EEPC may prevent doxorubicin-induced heart failure by modulating the antioxidant defense system, reducing reactive oxygen species-induced damage, preventing alterations of hemodynamic and endothelial function, and preventing damage to the cardiac structure. EEPC, especially at the highest dose tested, may be considered a cardioprotective coadjuvant to prevent doxorubicin-induced cardiotoxicity.

Ethnopharmacological approaches to Talinum paniculatum (Jacq.) Gaertn. - Exploring cardiorenal effects from the Brazilian Cerrado

ETHNOPHARMACOLOGICAL RELEVANCE

Talinum paniculatum (Jacq.) Gaertn. (Talinaceae), popularly known as "major gomes" and "erva gorda", is a non-conventional food plant extensively distributed throughout the Brazilian territory. In Brazilian folk medicine, this species is used as aphrodisiac, to treat gastrointestinal problems, and as a cardioprotective agent. However, there are no reports in the literature proving its cardiovascular effects.

AIM

To perform a whole-ethnopharmacological investigation of the cardiorenal properties of the ethanol soluble fraction from T. paniculatum (ESTP) in Wistar rats.

MATERIAL AND METHODS

First, plant samples were collected, properly identified and a morpho-anatomical characterization was carried out to provide quality control parameters. Then, ESTP was obtained and its chemical profile was determined by LC-DAD-MS. In addition, an acute toxicity assay was conducted in female Wistar rats in order to observe any toxic effects after one single administration. Finally, the diuretic and hypotensive potential of ESTP (30, 100 and 300 mg/kg) were investigated in male rats followed by the evaluation of its possible effects on peripheral vascular resistance.

RESULTS

Chemical compounds identified from ESTP were chlorogenic acids, amino acids, nucleosides, O-glycosylated flavones and organic acids. No signs of toxicity as well as no changes in urine volume or electrolyte elimination were observed after ESTP acute treatment. On the other hand, prolonged treatment with all doses of ESTP significantly increased urine volume and electrolyte excretion (Na⁺, K⁺ and Cl^-) without affecting blood pressure or heart rate. Apparently, these effects are involved with the activation of the small conductance calcium-activated potassium channels contributing to the increase of renal blood flow and glomerular filtration rate.

CONCLUSION

Data presented show important information about the ethnomedicinal properties of T. paniculatum. In addition, the study presents the ESTP as a possible herbal medicine, especially when a sustained diuretic effect is required.

Pharmacological safety of Plinia cauliflora (Mart.) Kausel in rabbits

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Fruit peels of Plinia cauliflora are widely used in Brazilian traditional medicine.

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No studies have proved the safety of its pharmacological effects.

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We assessed the safety pharmacology of P. cauliflora extract (EEPC) in rabbits.

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EEPC did not cause any significant changes in several physiological systems.

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These data provide important safety data for its clinical use.

Fruit peels of Plinia cauliflora (Mart.) Kausel are widely used in Brazilian traditional medicine, but no studies have proved the safety of its pharmacological effects on the respiratory, cardiovascular, and central nervous systems. The present study assessed the safety pharmacology of P. cauliflora in New Zealand rabbits. First, an ethanol extract (EEPC) was selected for the pharmacological experiments and chemical characterization. Then, different groups of rabbits were orally treated with EEPC (200 and 2000 mg/kg) or vehicle. Acute behavioral and physiological alterations in the modified Irwin test, respiratory rate, arterial blood gas, and various cardiovascular parameters (i.e., heart rate, blood pressure, and electrocardiography) were evaluated. The main secondary metabolites that were identified in EEPC were ellagic acid, gallic acid, O-deoxyhexosyl quercetin, and the anthocyanin O-hexosyl cyanidin. No significant behavioral or physiological changes were observed in any of the groups. None of the doses of EEPC affected respiratory rate or arterial blood gas, with no changes on blood pressure or electrocardiographic parameters. The present study showed that EEPC did not cause any significant changes in respiratory, cardiovascular, or central nervous system function. These data provide scientific evidence of the effects of this species and important safety data for its clinical use.

Antiatherosclerotic Properties of Echinodorus grandiflorus (Cham. & Schltdl.) Micheli: From Antioxidant and Lipid-Lowering Effects to an Anti-Inflammatory Role

Echinodorus grandiflorus is an important medicinal plant species that is native to South America. Despite extensive popular usage as a hypolipidemic drug, its effects as an atheroprotective agent remain unknown. The aim of this study was to evaluate the effects of an ethanol-soluble fraction that was obtained from E. grandiflorus (ESEG) leaves against the development of atherosclerosis in rabbits. Male rabbits received a diet that was supplemented with 1% cholesterol (cholesterol-rich diet [CRD]) for 60 days. After 30 days of the CRD, the animals were divided into five groups (n = 6) and treated with ESEG (10, 30, and 100 mg/kg), simvastatin (2.5 mg/kg), or vehicle once daily for 30 days. The negative control group was fed a cholesterol-free diet and treated orally with vehicle. At the end of 60 days, serum lipids, oxidized low-density lipoprotein, thiobarbituric acid reactive substances, nitrotyrosine, and serum interleukin 1 beta (IL-1β), IL-6, soluble intercellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1) levels were determined. Samples from the aortic arch and thoracic segment were also collected to investigate the tissue antioxidant defense system and perform histopathological analysis. Oral ESEG administration significantly reduced serum lipid levels in CRD-fed rabbits. This treatment also modulated the arterial antioxidant defense system by reducing lipid and protein oxidation. Similarly, serum IL-1β, IL-6, sICAM-1, and sVCAM-1 levels significantly decreased, accompanied by a reduction of atherosclerotic lesions in all arterial branches. These findings suggest that ESEG may be a new herbal medicine that can be directly applied for the treatment and prevention of atherosclerotic disease.

Safety assessment of MEFAS: an innovative hybrid salt of mefloquine and artesunate for malaria treatment

Malaria is a global public health problem that causes approximately 445 000 deaths annually worldwide, especially in underdeveloped countries. Because of the high prevalence and mortality of the disease, new and less toxic therapeutic agents need to be developed, such as MEFAS, a low-cost hybrid salt that consists of artesunate and mefloquine. However, the efficacy of MEFAS has been systematically demonstrated, its safety requires further investigation. This study investigated the acute toxicity of MEFAS and its precursors, artesunate, and mefloquine. A total of 42 female Swiss mice were divided into seven groups (n = 6/group) that were treated orally by gavage with vehicle (filtered water, negative control), MEFAS (50, 500, and 1000 mg/kg), and 1:1 concentrations of artesunate + mefloquine (50, 500, and 1000 mg/kg). Clinical signs of toxicity were observed for 14 d after treatment. On day 15, the animals were weighed, deeply anesthetized with isoflurane, and euthanized for subsequent collection of the liver, spleen, and kidneys. The relative organ weights were determined, followed by histopathological analysis. Artesunate + mefloquine produced toxic effects compared with the negative control group, reflected by changes in clinical signs, relative organ weights, and histopathological alterations. In MEFAS-treated animals, no changes were observed compared with the negative control group. These findings demonstrate that MEFAS is safer than artesunate + mefloquine after acute administration in mice.

Osteoprotective Effects of Tribulus terrestris L.: Relationship Between Dehydroepiandrosterone Levels and Ca2+-Sparing Effect

Osteoporosis is a systemic bone disease that is characterized by impairments in bone strength that predispose an individual to a higher risk of fractures. Despite the various etiologies, undoubtedly the most important factors are aging of the population and hypogonadism. Although several therapeutic options are available, pharmacological treatments have some risks. Among these are increases in the incidence of thrombosis, breast cancer, ovarian cancer, endometrial cancer, and muscle injury, among others. Herbal medication may be an alternative for the treatment of osteoporosis. Thus, the aim of this study was to evaluate the therapeutic effect of a standardized extract of Tribulus terrestris L. (TT) on ovariectomy (OVX)-induced bone loss in rats. Female rats were first subjected to OVX and treated with TT (3, 30, and 300 mg/[kg·day]) or furosemide (25 mg/kg) orally for 28 days. Bone densitometry and tibial histology were performed, and acute renal function and testosterone, dehydroepiandrosterone (DHEA), and estradiol levels were assessed. Prolonged treatment with TT stimulated bone mass gain in all ovariectomized animals, raising bone mass to levels that were similar to sham-operated rats. DHEA levels significantly increased in TT-treated rats. The TT group also had lower calcium (Ca²⁺) excretion that OVX control and furosemide-treated rats. Finally, the histopathological analyses showed the maintenance of bone turnover in all TT-treated groups. Overall, the results indicate that the standardized extract of T. terrestris exerted a bone-protective effect by increasing bone mineral density. This activity may be at least partially attributable to an increase in serum DHEA levels and a Ca²⁺-sparing effect.

Influence of Luehea divaricata Mart. extracts on peripheral vascular resistance and the role of nitric oxide and both Ca+2-sensitive and Kir6.1 ATP-sensitive K+ channels in the vasodilatory effects of isovitexin on isolated perfused mesenteric beds

BACKGROUND

Luehea divaricata Mart. (Malvaceae) is an important medicinal species widely used by indigenous and riverside populations of the Brazilian Pantanal region. It has been shown that the several extracts obtained from leaves of this species have important cardioprotective effects. Nevertheless, the secondary metabolites responsible for this activity, as well as the molecular mechanisms responsible for their pharmacological effects remain unknown.

PURPOSE

To carry out a biomonitoring study to identify possible active metabolites present in different ESLD fractions and evaluate the mechanisms responsible for the vasodilatory effects on isolated perfused mesenteric beds.

METHODS

First, ESLD was obtained from L. divaricata leaves and a liquid-liquid fractionation was performed. The resulting fractions were analyzed by liquid chromatography-mass spectrometry. Then, the possible vasodilatory effects of ESLD, chloroform, ethyl acetate, n-butanolic and aqueous fractions on perfused arterial mesenteric vascular beds were evaluated. Finally, the molecular mechanisms involved in vasodilator responses of the aqueous fraction and its chemical component, isovitexin, on the mesenteric arteriolar tone were also investigated.

RESULTS

In preparations with functional endothelium ESLD, n-butanolic, aqueous fraction and isovitexin dose-dependently reduced the perfusion pressure in mesenteric vascular beds. Endothelium removal or inhibition of nitric oxide synthase enzymes by L-NAME reduced the vasodilatory effects induced by aqueous fraction and isovitexin. Perfusion with nutritive solution containing 40 mM KCl abolished the vasodilatory effect of all aqueous fractions and Isovitexin doses. Treatment with glibenclamide, a Kir6.1 (ATP-sensitive) potassium channels blocker, tetraethylammonium, a non-selective KCa (calcium-activated) potassium channels blocker, or apamin, a potent blocker of small conductance Ca²⁺-activated (SK KCa) potassium channels reduced by around 70% vasodilation induced by all aqueous fractions and isovitexin doses. In addition, association of tetraethylammonium and glibenclamide, or L-NAME and glibenclamide, fully inhibited aqueous fraction and Isovitexin -induced vasodilation.

CONCLUSION

This study showed that AqueFr obtained from Luehea divaricata and its metabolite - isovitexin - has important vasodilatory effects on MVBs. Apparently, these effects are dependent on endothelium-NO release and both SK KCa K⁺ channels and Kir6.1 ATP-sensitive K⁺ channels activation in the vascular smooth muscle.

Redox regulation and NO/cGMP plus K+ channel activation contributes to cardiorenal protection induced by Cuphea carthagenensis (Jacq.) J.F. Macbr. in ovariectomized hypertensive rats

BACKGROUND

One of the medicinal plants widely used by the population in the treatment of hypertension, atherosclerosis and circulatory disorders is Cuphea carthagenensis (Jacq.) J.F. Macbr. (Lythraceae), popularly known as 'sete sangrias', being found in Brazil, Hawaii and in South Pacific Islands. Despite the widespread use of this species by the population, its long-term antihypertensive and cardioprotective activities have not yet been scientifically evaluated.

PURPOSE

To evaluate the possible cardioprotective effects of an ethanol-soluble fraction obtained from C. carthagenensis (ESCC) using ovariectomized hypertensive rats to simulate a broad part of the female population over 50 years of age affected by hypertension. In addition, the molecular mechanism that may be responsible for its cardiorenal protective effects was also explored.

METHODS

Female Wistar rats were submitted to surgical procedures of bilateral ovariectomy and induction of renovascular hypertension (two-kidneys, one-clip model). The sham-operated group was used as negative control. ESCC was obtained and a detailed phytochemical investigation about its main secondary metabolites was performed. ESCC was orally administered at doses of 30, 100 and 300  mg/kg, daily, for 28 days, 5 weeks after surgery. Enalapril (15  mg/kg) was used as standard antihypertensive drug. Renal function was evaluated on days 1, 7, 14, 21 and 28. At the end of the experimental period, systolic, diastolic, mean arterial pressure and heart rate were recorded. The activity of the tissue enzymatic antioxidant system, thiobarbituric acid reactive substances, nitrotyrosine, nitrite, aldosterone and vasopressin levels, in addition to the activity of the angiotensin-converting enzyme were also evaluated. Additionally, vascular reactivity to acetylcholine, sodium nitroprusside, and phenylephrine, and the role of nitric oxide, prostaglandins, and K⁺ channels in the vasodilator response of ESCC on the mesenteric vascular bed were also investigated.

RESULTS

ESCC-treatment induced an important cardiorenal protective response, preserving renal function and preventing elevation of blood pressure and heart rate in ovariectomized hypertensive rats. In addition, prolonged treatment with ESCC recovered mesenteric vascular reactivity at all doses used. This effect was associated with an important modulation of the antioxidant defense system with a possible increase in NO bioavailability. Additionally, NO/cGMP activation and K⁺ channel opening-dependent vasodilator effect was observed on the mesenteric vascular bed, indicating a potential mechanism for the cardiovascular effects of ESCC.

CONCLUSION

A 28-days ESCC treatment reduces the progression of the cardiorenal disease in ovariectomized hypertensive rats. These effects seem to be involved with an attenuation of oxidative and nitrosative stress, affecting endothelial nitric oxide production and K⁺ channel opening in smooth muscle cells.

Heart-Protective Effects of Echinodorus grandiflorus in Rabbits That Are Fed a High-cholesterol Diet

Excess weight and dyslipidemia are among the most serious health problems in Western societies. These conditions enhance the risk of cardiac disease and have been linked with a higher prevalence of cardiac arrhythmias and sudden death. The present study investigated the cardioprotective effects of Echinodorus grandiflorus on ventricular remodeling in rabbits that were fed a 1% cholesterol-rich diet. We first obtained an ethanol-soluble fraction of E. grandiflorus and performed a detailed phytochemical study by liquid chromatography-DAD/ESI-MS. For 60 days, male rabbits were fed the cholesterol-rich diet or a diet without the addition of cholesterol. After 30 days, different groups of rabbits were treated with the ethanol-soluble fraction of E. grandiflorus (10, 30, and 100 mg/kg, p. o.), simvastatin (2.5 mg/kg), or vehicle once daily for 30 days. At the end of 60 days, the serum lipoprotein ratio, electrocardiographic profile, histopathological alterations, and the cardiac antioxidant defense system were investigated. Echocardiographic analysis showed morphological and functional alterations in cholesterol-rich diet-fed animals, indicating left ventricle hypertrophy. The total cholesterol/high-density lipoprotein ratio and low-density lipoprotein/high-density lipoprotein ratio were significantly higher in cholesterol-rich diet-fed rabbits. Myocardial flaccidity, fatty degeneration, and concentric left ventricular hypertrophy were observed. An increase in lipid peroxidation levels, a decrease in superoxide dismutase activity, and a decrease in reduced glutathione levels were observed in the myocardium of all cholesterol-rich diet-fed rabbits. Treatment with the ethanol-soluble fraction of E. grandiflorus, especially the highest dose, significantly reduced all of these alterations, thus demonstrating the cardioprotective effect of the ethanol-soluble fraction of E. grandiflorus on cardiac changes that are induced by a cholesterol-rich diet.

Biomonitoring the cardiorenal effects of Luehea divaricata Mart.: An ethnoguided approach

ETHNOPHARMACOLOGICAL RELEVANCE

Luehea divaricata Mart. (Malvaceae) is an important medicinal species that is widely used as a diuretic in the Brazilian Pantanal region. An ethanolic supernatant that was obtained from an infusion of leaves of this species (ESLD) was recently shown to exert hypotensive and diuretic activity. Nevertheless, the secondary metabolites that are responsible for this activity and the molecular mechanisms of pharmacological action remain unknown.

AIM

We performed a detailed study to identify possible active metabolites that are present in different ESLD fractions and investigated their effects on renal and peripheral arteriolar tone. We further evaluated their interrelations with sustained diuretic and hypotensive actions.

MATERIALS AND METHODS

The ESLD was first obtained from L. divaricata leaves, and liquid-liquid fractionation was performed. The fractions were analyzed by liquid chromatography-mass spectrometry. An ethyl acetate fraction (AceFr), n-butanolic fraction (ButFr), and aqueous fraction (AqueFr) were then orally administered in male Wistar rats in a single dose or daily for 7 days. The doses were previously defined based on the yield that was obtained from each fraction. Hydrochlorothiazide was used as a positive control. Blood pressure, heart rate, urinary volume, pH, density, and urinary sodium, potassium, chloride, and calcium levels were measured. Serum levels of nitrite, thiobarbituric acid reactive species, nitrotyrosine, aldosterone, vasopressin, and plasma angiotensin converting enzyme activity were also measured. Finally, the direct effects of the ButFr on renal and mesenteric arteriolar tone and the role of nitric oxide and prostaglandins in the renal and hemodynamic effects were investigated.

RESULTS

Of the fractions that were tested, only the ButFr exerted significant diuretic and saluretic effects. The AceFr and ButFr also had acute hypotensive effects, but only the ButFr maintained its response after 7 days of treatment. Prolonged treatment with the ButFr increased serum nitrite levels and significantly reduced oxidative and nitrosative markers of stress. Additionally, the ButFr caused a vasodilatory response in the renal and mesenteric arteriolar beds through the release of nitric oxide and prostaglandins. Finally, the diuretic and hypotensive effects of the ButFr were completely blocked by pretreatment with Nω-nitro-L-arginine methyl ester and indomethacin, thus demonstrating the direct involvement of nitric oxide and prostaglandins in these effects.

CONCLUSION

The ButFr that was obtained from Luehea divaricata exerted sustained diuretic and hypotensive effects. These effects were apparently attributable to the release of nitric oxide and prostaglandins, which reduce renal and peripheral arteriolar tone and lead to an increase in the glomerular filtration rate and a reduction of global peripheral resistance. These findings suggest that the ButFr may be a potential complementary therapy for several conditions in which diuretic and hypotensive effects are required.

Evaluation of Reproductive Toxicology of Aqueous Extract of Yerba Mate (Ilex paraguariensis A. St.-Hil.), a Traditional South American Beverage

Yerba mate (Ilex paraguariensis A. St.-Hil.; Aquifoliaceae) is a popular tonic and stimulant beverage that is widely consumed in different South American countries. Estimates indicate the consumption of >1 L per day in southern Brazil and Uruguay. Despite its relatively high consumption, data on reproductive toxicity during critical periods of gestation remain unclear. Thus, we evaluated the effects of an aqueous extract of I. paraguariensis leaves ("chimarrão" [IPC]) at two critical periods of gestation in Wistar rats: preimplantation embryonic stage and fetal organogenesis. Pregnant Wistar rats were orally treated with IPC (3, 30, and 300 mg/kg) from days 1 to 7 or 8 to 21 of pregnancy. The respective control groups received vehicle. During treatment, clinical signs of maternal toxicity, maternal body weight, and food and water intake were monitored. The rats were killed on days 8 and 20 of pregnancy, and the following parameters were evaluated: weight of the maternal uterus, weight of the liver, weight of the kidneys, weight of the spleen, total embryo implantation, preimplantation loss, the mean of live fetuses, the percentage of dead fetuses, fetus weight, and fetal malformation. The aqueous extract of the leaves of I. paraguariensis L. did not present any deleterious effects on preimplantation embryos or the organogenesis of offspring from female Wistar rats. These safety data provide evidence that IPC may be safe for consumption during gestation.

90-Day Oral Toxicity Assessment of Tropaeolum majus L. in Rodents and Lagomorphs

Tropaeolum majus L., popularly known as nasturtium, is a species widely used in the form of infusions and salads. In the last years, the antihypertensive, diuretic, and calcium and potassium sparing activities of T. majus preparations were shown. Moreover, no preclinical 90-day oral toxicity studies were conducted. Thus, this study evaluated the toxicity of the hydroethanolic extract obtained from T. majus (HETM) leaves in female and male mice, rats, and rabbits. Swiss mice and Wistar rats were treated with HETM (75, 375, and 750 mg/kg). The doses of rabbits (30, 150, and 300 mg/kg) were calculated by allometric extrapolation. The control groups received vehicle. The animals were orally treated, daily, for 90 days. At the end, the animals were anesthetized, and body weight gain, relative weight of liver, kidney, and spleen, and histopathological changes were evaluated. Serum hematological and biochemical parameters were also analyzed. No alterations were found in body and organ weights or in histopathological and biochemical evaluation. Hematological analyses revealed small changes in lymphocytes and neutrophil counts in rats after administration of 750 mg/kg of HETM. These results showed that 90-day use of T. majus is safe in rodents and lagomorphs.

Molecular docking to Toxoplasma gondii thymidylate synthase-dihydrofolate reductase and efficacy of raltitrexed in infected mice

Toxoplasmosis is a zoonosis of worldwide distribution. Currently, two drugs, pyrimethamine and sulfadiazine, are used as a reference in the treatment of toxoplasmosis, but the resistance of Toxoplasma gondii appears as a relevant public health problem. In order to identify new drugs to toxoplasmosis treatment, we performed a molecular docking of raltitrexed to T. gondii thymidylate synthase-dihydrofolate reductase (TS-DHFR) and also evaluated its efficacy in infected mice. Initially, raltitrexed was docked on the crystallographic structures of TS-DHFR from T. gondii and Mus musculus. Then, 48 h after infection with the T. gondii RH strain, different groups of mice received an oral dose of raltitrexed (0.15, 0.75, and 1.5 mg kg^-1). Two days after treatments, raltitrexed was able to prevent mortality and reduce the number of tachyzoites in the peritoneal fluid and liver imprints from infected mice. The results showed that raltitrexed has important protective activities against the T. gondii RH strain. Molecular docking still suggests that the effects against the parasite may be dependent on the inhibition of T. gondii thymidylate synthase. This study opens new perspectives for the use of raltitrexed in patients infected with T. gondii, especially when conventional treatments do not exhibit the expected efficacy.

Involvement of bradykinin B2 and muscarinic receptors in the prolonged diuretic and antihypertensive properties of Echinodorus grandiflorus (Cham. & Schltdl.) Micheli

BACKGROUND

Although Echinodorus grandiflorus (Cham. & Schltr.) Michel are used in Brazilian folk medicine as a diuretic drug, to date, no study has evaluated the mechanisms involved in this activity after prolonged administration in rats.

AIM OF THE STUDY

Evaluate the possible mechanisms involved in the prolonged diuretic activity of ethanol soluble fraction obtained from Echinodorus grandiflorus (ES-EG) and to assess its relationship with hypotensive and antihypertensive activity using normotensive rats and those with renovascular hypertension (2K1C).

METHODS

The diuretic effects of ES-EG (30-300 mg/kg; p.o.) were compared with hydrochlorothiazide in a repeated-dose treatment for 7 days. The urinary volume and sodium, potassium, chloride, bicarbonate contents, conductivity, pH and density were estimated in sample collected in 24 h for 7 days. Plasma sodium, potassium, total protein, urea, creatinine, aldosterone, vasopressin, nitrite, acetylcholinesterase concentration and angiotensin converting enzyme (ACE) activity were measured in samples collected at the end of the experimental period (seventh day). Using pharmacological antagonists or inhibitors, the involvement of bradykinin, prostaglandin, acetylcholine and nitric oxide (NO) in ES-EG-induced diuresis was determined. In addition, activities of erythrocytary carbonic anhydrase and renal Na+/K+/ATPase were evaluated in vitro.

RESULTS

ES-EG increased diuresis similarly to hydrochlorothiazide and also presented HCO3-sparing effects and increased serum nitrite levels. Moreover, the intraduodenal administration of ES-EG induces significant hypotensive and antihypertensive effects in 2K1C rats. Previous treatment with HOE-140, indometacin and atropine fully avoided the diuretic effect of ES-EG, and including L-NAME pre-administration, it prevented the hypotensive and hypertensive activity induced by ES-EG. In addition, the association between HOE-140 and atropine or indometacin and L-NAME fully inhibited the hypotensive and antihypertensive effects of ES-EG. The 7-day treatment with ES-EG resulted in increased plasma nitrite levels. All other parameters were not affected by treatment with ES-EG.

CONCLUSIONS

Our results suggest that the mechanisms through which Echinodorus grandiflorus extracts induce prolonged diuresis and reduce blood pressure in normotensive and 2K1C rats are mainly related to activation of muscarinic and bradykinin receptors with direct effects on prostaglandins and nitric oxide pathways.

Fetopathies associated with exposure to angiotensin converting enzyme inhibitor from Tropaeolum majus L

The prevalence of the use of herbal medicines is on the rise across the world, especially amongst pregnant women. A fact that draws attention is that many species commonly used by pregnant women, including the Tropaeolum majus L. (Tropaeolaceae), also present inhibitory activity on the angiotensin-converting enzyme (ACE). Herein, we have investigated the effects of T. majus extract (HETM) on fetal development, evaluating its relationship with possible ACE inhibitory activity. Pregnant Wistar rats were treated with different HETM doses (3, 30 and 300 mg/kg/day) from gestational days 8-20. Rats were sacrificed on the day 20 of pregnancy and the following parameters were evaluated: clinical symptoms of maternal toxicity; maternal body weight; feed and water intake; maternal liver, kidney, and ovary weights, maternal ACE activity and aldosterone levels, live fetuses mean; dead fetuses percentage, fetus weight, and fetal malformation. All pregnant rats treated with high HETM doses showed significant reduction in plasma ACE activity accompanied by a decrease in serum aldosterone levels. Moreover, significant changes in fetal development were observed, including growth retardation and renal damage after 20 days of gestation. Thus, data presented demonstrate the significant effects of the use of HETM on fetal development during pregnancy.

Atheroprotective effects of Cuphea carthagenensis (Jacq.) J. F. Macbr. in New Zealand rabbits fed with cholesterol-rich diet

ETHNOPHARMACOLOGICAL RELEVANCE

Although Cuphea carthagenensis (Jacq.) J. F. Macbr. is used in Brazilian folk medicine in the treatment of atherosclerosis and circulatory disorders, no study evaluating these effects has been conducted. The aim of this study was to evaluate the possible hypolipemiant and antiatherogenic activity of the ethanol soluble fraction obtained from C. carthagenensis (ES-CC) in an experimental atherosclerosis model using New Zealand (NZ) rabbits undergoing cholesterol-rich diet (CRD).

MATERIAL AND METHODS

Dyslipidemia and atherogenesis were induced by administration of standard commercial diet increased of 1% cholesterol (CRD) for 8 weeks. ES-CC was orally administered at doses of 10, 30 and 100mg/kg, once daily for four weeks, starting from the 4th week of CRD diet. Body weight measurements were weekly carried out from the beginning of experiments for 8 weeks. Serum levels of triglyceride (TG), total cholesterol (TC) and their fractions (LDL-C, VLDL-C and HDL-C) were measured at the beginning of experiments and at weeks four and eight. After euthanasia of rabbits, aorta segments (aortic arc, thoracic, abdominal and iliac segments) were macroscopically and microscopically evaluated and the intima and media layers of the arteries were measured. Additionally, the antioxidant activity of ES-CC and its influence on the functioning of hepatic antioxidant enzymes were also determined.

RESULTS

CRD induced dyslipidemia and major structural changes in the aortic wall. In addition, an increase in lipid peroxidation and a reduction of hepatic glutathione and serum nitrite levels were observed. Treatment with ES-CC was able to prevent the increase in TC, LDL-C, VLDL-C levels and triglycerides and promoted an increase in HDL-C levels in NZ rabbits. These effects were accompanied by a significant reduction in oxidative stress and modulation of the catalase and superoxide dismutase function. Moreover, the intima and media layers of the arterial segments were significantly reduced by ES-CC treatment.

CONCLUSIONS

This study demonstrated that ES-CC reduces serum lipids and hepatic oxidative stress when orally administered to NZ rabbits. In addition, it was able to prevent the development of CRD-induced atherosclerosis.

PHEROMONES FROM MALE DOMESTIC MICE INFLUENCES THE SEXUAL FUNCTION AND GONADAL STEROIDS LEVELS OF FEMALE LABORATORY RATS

It is well established that the behavior of different mammalians, including rodents, may undergo profound changes in the presence of individuals of other species. Therefore, the aim of this study was to verify if the presence of pheromones from male mice could influence the reproductive parameters of female rats. Twenty Swiss (SW) male mice and 16 Long Evans (LE) female Rats were housed in separate rooms, with communication in the ceiling in its entire length. A continuous flow of air was planned to pass through the room of the mice before the room of the rats and finally be exchanged with the external environment. During 45 days, vaginal smears were collected. Relative weights of reproductive organs, estradiol, progesterone, and dehydroepiandrosterone levels were also measured. The total duration of the estrous cycle and relative organ weight remained unchanged. On the other hand, the proestrus and estrus phases, as well as the estradiol levels were increased, while the diestrus phase was significantly reduced. The results have shown that maintaining LE female rats in the presence of pheromones from male SW mice can significantly change the sexual function and gonadal steroid levels.

Ethnopharmacological investigation of the diuretic and hemodynamic properties of native species of the Brazilian biodiversity

ETHNOPHARMACOLOGICAL RELEVANCE

Although Echinodorus grandiflorus, Cuphea carthagenensis, and Phyllanthus tenellus infusions are used in Brazilian folk medicine due to their possible diuretic effect, none of these species was critically investigated as a diuretic drug. So, the aim of this study was to evaluate the possible acute diuretic activity of ethanol soluble fractions (ES) obtained from these species and assess the relationship between renal cortical blood flow and their antioxidant and hypotensive activity using normotensive Wistar rats.

MATERIAL AND METHODS

The preparation obtained from E. grandiflorus (ES-EG), C. carthagenensis (ES-CC), and P. tenellus (ES-PT) infusions was orally administered in a single dose to rats. Urine excretion rate, pH, density, conductivity and Na(+), K(+), Cl(-) and HCO3(-) contents were measured in the urine of saline-loaded animals. Concentration of electrolytes, total protein, urea, creatinine, and angiotensin converting enzyme (ACE) activity were evaluated in collected serum. The involvement of the renal cortical blood flow and antioxidative activity in the hypotensive and diuretic effects was also determined.

RESULTS

Water and Na(+), Cl(-) and Na(+) excretion rates were significantly increased by ES-EG, while urinary bicarbonate excretion was reduced. Moreover, ES obtained from E. grandiflorus was able to significantly increase renal blood flow and reduce mean arterial pressure and oxidative stress in "in vitro" and "in vivo" models. All other parameters evaluated were not affected by any treatment.

CONCLUSION

The results presented here shown that the ES-EG obtained from E. grandiflorus leaves shown a significant diuretic and hypotensive activity and suggest that these effects could be related with an important renal and systemic vasodilator effect. In addition, it was shown for the first time that the pharmacological effects of ES obtained from P. tenellus and C. carthagenensis do not support its popular use as a diuretic agent.

Cardiovascular protective effects of Casearia sylvestris Swartz in Swiss and C57BL/6 LDLr-null mice undergoing high fat diet

ETHNOPHARMACOLOGICAL RELEVANCE

Although Casearia sylvestris Swartz is used in Brazilian folk medicine to treat obesity, no study has been conducted to evaluate the effects of this species in an experimental model of dyslipidemia and atherosclerosis. So, the aim of this study was to evaluate possible hypolipemiant and antiatherogenic activity of the methanolic extract obtained from Casearia sylvestris (MECS) using Swiss and C57BL/6 LDLr-null mice undergoing high fat diet (HFD).

MATERIAL AND METHODS

Dyslipidemia and atherogenesis were induced by the administration of commercial HFD for 4 weeks. The MECS was administered orally at doses of 250 and 500mg/kg, once a day, for two weeks, starting from the 2nd week of HFD. The gain in body weight and systolic blood pressure (SBP) were measured weekly over the four week study. At the end of the experiments the levels of triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and very low-density lipoprotein cholesterol (VLDL-C) were measured by colorimetric method. Aldosterone, vasopressin and angiotensin converting enzyme (ACE) activity were also evaluated in collected serum. The renal function, atherogenic index serum (AIS) and in vitro antiplatelet activity were investigated. Additionally, histopathological analyzes were performed to determine the intima-media thickness (IMT) and intima media ratio (IMR) in aorta samples.

RESULTS

The HFD induced dyslipidemia and major structural changes in the aortic wall, including raising of the systolic blood pressure in LDLr-null mice. In addition, we observed an increase in lipid peroxidation accompanied by a reduction of serum nitrite. The treatment with MECS was able to prevent the increase of SBP, TC, LDL-C, VLDL-C and triglycerides levels and increase HDL-C in Swiss and LDLr-null mice. These effects were accompanied by a significant reduction in oxidative stress. Moreover, AIS, IMT and IMR were significantly reduced in MECS-treated mice, and the extract was able to reduce platelet aggregation in vitro.

CONCLUSION

This study demonstrated that MECS reduces the serum lipids and oxidative stress when orally administered to Swiss and LDLr-null mice. In addition, it was able to prevent arterial thickening induced by HFD and to inhibit platelet aggregation in vitro.

Role of prostaglandin/cAMP pathway in the diuretic and hypotensive effects of purified fraction of Maytenus ilicifolia Mart ex Reissek (Celastraceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Although Maytenus ilicifolia is used in Brazilian folk medicine as a diuretic drug, no study has been conducted to this date in order to evaluate this ethnopharmacological statement. So, the aim of this study was to evaluate possible mechanisms involved in acute diuretic activity of the ethanolic supernatant of the infusion (SEI) obtained from Maytenus ilicifolia and to assess its relationship with a hypotensive activity by a bioassay-guided fractionation using normotensive Wistar rats.

MATERIAL AND METHODS

The preparation obtained from the infusion (SEI) and their respective fractions (Fr·H2O and Fr·EtOAc) were orally administered in a single dose to rats. The urine excretion rate, pH, density, conductivity and content of Na(+), K(+), Cl(-) and HCO3(-) were measured in the urine of saline-loaded animals. Samples of the concentration of electrolytes, urea, creatinine, aldosterone, vasopressin and angiotensin converting enzyme (ACE) activity were evaluated in collected serum. The hypotensive activity and the involvement of nitric oxide, bradykinin and prostaglandin/cAMP pathway in the hypotensive and diuretic effects were also determined.

RESULTS

Water and Na(+) excretion rate were significantly increased by Fr·EtOAc and the arterial pressure was significantly reduced, while the urinary excretion of potassium and chloride were reduced. Pre-treatment with indomethacin or DDA (2',5'-dideoxyadenosine) significantly reduced the hypotensive and diuretic activity observed. All other parameters evaluated were not affected by any treatment.

CONCLUSION

The present study reveals that Fr·EtOAc obtained from Maytenus ilicifolia may present compounds responsible for diuretic and hypotensive activities, and this effect, could involve the prostaglandin/cAMP pathway.

Study on the developmental toxicity of combined artesunate and mefloquine antimalarial drugs on rats

Antimalarial drug combinations containing artemisinins (ACTs) have become first choice therapies for Plasmodium falciparum malaria. Data on safety of ACTs in pregnancy are limited and no previous study has been conducted on the developmental toxicity of artesunate-mefloquine combinations on the first trimester of gestation. To evaluate the developmental toxicity of an artesunate/mefloquine combination, pregnant rats were treated orally with artesunate (15 and 40 mg/kg bwt/day), mefloquine (30 and 80 mg/kg bwt/day) and artesunate/mefloquine (15/30 and 40/80 mg/kg bwt/day) on gestation days 9-11. Dams were C-sectioned on day 20, and their uteri and fetuses removed and examined for soft tissue and skeleton abnormalities. Artesunate increased embryolethality and the incidence of limb long bone malformations on the absence of overt maternal toxicity. Mefloquine (80 mg/kg bwt/day) was maternally toxic and enhanced fetal variations. Combination of artesunate and mefloquine did not enhance their toxicity compared to the toxicity observed after its separate administration. Embryotoxicity of artesunate was apparently attenuated when it is co-administered with mefloquine.

Evaluation of subchronic toxicity of the hydroethanolic extract of Tropaeolum majus in Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

The use of medicinal plants for the treatment of diseases usually comes from the belief that they present low toxicity due their natural origin. However, it is necessary a toxicological and pharmacological evaluation for these plants. Tropaeolum majus is a medicinal plant used in popular medicine to treat several diseases, including cardiovascular disorders, urinary tract infections and asthma. Even though several studies proved its therapeutic effects, there are few toxicological studies with this species.

AIM OF THE STUDY

The present study was carried out to evaluate the subchronic toxicity of the hydroethanolic extract obtained from leaves of T. majus (HETM) in Wistar rats.

MATERIAL AND METHODS

Male and female Wistar rats received three doses of HETM (75, 375 and 750 mg/kg) for 28 days. After the treatments biochemical, hematological and histopathological parameters were analyzed.

RESULTS

No significant alterations in the animal's body weight gain, relative organs weight, serum biochemical analysis, hematological or histopathological analyses of liver, kidneys and spleen were observed.

CONCLUSIONS

These results demonstrate the absence of subchronic toxicity due to oral treatment with HETM for 28 days in Wistar rats. However, other toxicological studies are necessary to evaluate the total safety of this plant.

Mechanisms underlying the diuretic effects of Tropaeolum majus L. extracts and its main component isoquercitrin

ETHNOPHARMACOLOGICAL RELEVANCE

Previous studies have shown that the extracts obtained from Tropaeolum majus L., and its main compound isoquercitrin (ISQ), exhibit pronounced diuretic effects, supporting the ethnopharmacological use of this plant. The aim of this study was to evaluate the efficacy and mechanisms underlying the diuretic action of an ethanolic extract of Tropaeolum majus (HETM), its purified fraction (TMLR), and its main compound ISQ, in spontaneously hypertensive rats (SHR).

MATERIALS AND METHODS

The diuretic effects of HETM (300mg/kg; p.o.), TMLR (100mg/kg; p.o.), and ISQ (10mg/kg; p.o.), were compared with classical diuretics in 7days repeated-dose treatment. The urinary volume, sodium, potassium, chloride, bicarbonate, conductivity, pH and density were estimated in the sample collected for 15h. The plasmatic concentration of sodium, potassium, urea, creatinine, aldosterone, vasopressin, nitrite and angiotensin converting enzyme (ACE) activity were measured in samples collected at the end of the experiment (seventh day). Using pharmacological antagonists or inhibitors, we determine the involvement of bradykinin, prostaglandin and nitric oxide (NO) in ISQ-induced diuresis. In addition, reactive oxygen species (ROS) and the activity of erythrocytary carbonic anhydrase and renal Na(+)/K(+)/ATPase were evaluated in vitro.

RESULTS

HETM, TMLR and ISQ increased diuresis similarly to spironolactone and also presented K(+)-sparing effects. All groups presented both plasmatic aldosterone levels and ACE activity reduced. Previous treatment with HOE-140 (a B2-bradykinin receptor antagonist), or indomethacin (a cyclooxygenase inhibitor), or L-NAME (a NO synthase inhibitor), fully avoided the diuretic effect of ISQ. In addition, the 7days treatment with ISQ resulted in increased plasmatic levels of nitrite and reducing ROS production. Moreover, the renal Na(+)/K(+)/ATPase activity was significantly decreased by ISQ.

CONCLUSION

Our results suggest that the mechanisms through ISQ and extracts of Tropaeolum majus increase diuresis in SHR rats are mainly related to ACE inhibition, increased bioavailability of bradykinin, PGI2, and nitric oxide, besides an inhibitory effect on Na(+)/K(+)-ATPase.

Screening for in vivo (anti)estrogenic and (anti)androgenic activities of Tropaeolum majus L. and its effect on uterine contractility

ETHNOPHARMACOLOGICAL RELEVANCE

Tropaeolum majus L. (Tropaeolaceae) is a medicinal herb popularly used in Brazil for treatment of inflammatory and cardiovascular diseases. Despite some published data on its efficacy, there are still few toxicological data describing the safety of this plant. The aim of this study was to evaluate the (anti)estrogenic and (anti)androgenic activity of the hydroethanolic extract obtained from Tropaeolum majus L. (HETM), as well as its possible effects on uterine contractility.

MATERIALS AND METHODS

Three experimental protocols were performed, (a) uterotrophic assay, (b) Hershberger assay and (c) an ex vivo test to investigate the effects of maternal administration of HETM on uterine contractility at the end of pregnancy. In all protocols three doses of the HETM were administered to Wistar rats: 3, 30 and 300mg/kg.

RESULTS

In vivo tests for detection of (anti)androgenic and (anti)estrogenic activities did not show any significant alterations. Similarly, no alterations were observed on uterine contractility induced by oxytocin and arachidonic acid.

CONCLUSIONS

HETM was unable to produce (anti)estrogenic or (anti)androgenic activities in the short-term in vivo screening assays performed. In addition, there was no evidence that HETM can affect uterine contractility following gestational exposure of rats.

Diuretic and potassium-sparing effect of isoquercitrin-an active flavonoid of Tropaeolum majus L

AIM OF THE STUDY

Previous studies have shown that the extracts obtained from Tropaeolum majus L. exhibit pronounced diuretic effects supporting the ethnopharmacological use of this plant as diuretic. In the present work, phytochemical investigation, guided by bio-assay in spontaneously hypertensive rats (SHR), was carried out in order to identify the compounds responsible for diuretic action.

MATERIAL AND METHODS

Chromatographic fractionation of the hydroethanolic extract yielded an active fraction (TMLR) rich in isoquercitrin. TMLR (25-100mg/kg) and isoquercitrin (5-10mg/kg), as well the reference drug hydrochlorothiazide (10mg/kg) were orally administered in a single dose or daily for 7 days to SHR. The urine excretion rate, pH, density, conductivity and content of sodium (Na(+)) and potassium (K(+)) electrolytes were measured in the urine of saline-loaded animals.

RESULTS

The urinary excretion rate was dose-dependently increased in both TMLR and isoquercitrin groups, as well as Na(+). Despite the changes in urinary excretion of electrolytes, the plasmatic levels of Na(+) and K(+) had not been changed. In addition, we did not find any evidence of renal toxicity or other adverse effects in these animals, even after prolonged treatment with TMLR or isoquercitrin.

CONCLUSION

This research supports and extends the ethnomedicinal use of T. majus as diuretic. This activity seems to be associated to the presence of the flavonol isoquercitrin.

Antihypertensive effects of isoquercitrin and extracts from Tropaeolum majus L.: evidence for the inhibition of angiotensin converting enzyme

AIM OF THE STUDY

Previous studies have shown that the extracts obtained from Tropaeolum majus L. exhibit pronounced diuretic properties. In the present study, we assessed whether the hypotensive and/or antihypertensive mechanism of hydroethanolic extract (HETM), semi-purified fraction (TMLR) obtained from T. majus and the flavonoids isoquercitrin (ISQ) and kaempferol (KPF) can be mediated by their interaction with angiotensin converting enzyme (ACE).

METHODS AND METHODS

Firstly, to evaluate changes in mean arterial pressure (MAP), different groups of normotensive and spontaneously hypertensive rats (SHR) were orally and intraduodenally treated with HETM (10-300 mg/kg) and TMLR (12.5-100mg/kg) and intravenously treated with ISQ and KPF being later anesthetized with ketamine (100mg/kg) and xylazine (20mg/kg). The left femoral vein and the right carotid artery were isolated, and polyethylene catheters were inserted for ISQ and KPF (0.5-4 mg/kg) administration and blood pressure recording, respectively. The plasmatic ACE activity was evaluated to indirect fluorimetry, in serum samples after orally treatment with HETM, TMLR, ISQ and KPF.

RESULTS

The oral administration of the HETM and its TMLR significantly reduced, in a dose-dependent manner, the MAP in both normotensive and SHR. In addition, these preparations significantly decreased the MAP for up to 3h after the administration of the extract. Additionally, the intravenous administration of ISQ, but not KPF, decreased MAP in rats. Otherwise, neither the extracts nor ISQ affected the heart rate. The oral administration of the HETM, TMLR or ISQ reduced ACE activity in serum samples at 90 min after administration. Finally, the intravenous administration of ISQ caused a significant reduction in the hypertensive response to angiotensin I, but not angiotensin II in normotensive rats.

CONCLUSION

Our results show that the hypotensive effects caused by the HETM, as well as by its TMLR, may be associated with the high levels of the flavonoid ISQ found in this plant. In addition, ISQ-induced hypotension in rats is an event dependent on the inhibition of angiotensin II generation by ACE.

Natriuretic and diuretic effects of Tropaeolum majus (Tropaeolaceae) in rats

Tropaeolum majus L. (Tropaeolaceae), popularly known as "chaguinha", is well recognized in Brazilian traditional medicine as diuretic agent, although no scientific data have been published to support this effect.

AIM OF THE STUDY

To evaluate the diuretic activity of the infusion and the hydroethanolic extract (HETM) of Tropaeolum majus, and possible mechanism of action.

MATERIAL AND METHODS

The infusions (2,5 - 10%) and the HETM doses (150, 300 mg/kg) were orally administered to rats. Urinary excretion, the electrolytes levels, and urea and creatinine were measured in of saline-loaded rats.

RESULTS

The oral administration of 10% (corresponding to 500 mg/kg) of the infusion increased significantly the urinary Na(+) excretion. Only the oral administration of 300 mg/kg of HETM increased significantly the urinary and Na(+) excretion. Prolonged administration of the HETM (300 mg/kg) significantly increased diuresis and the urinary excretion of Na(+), but others parameters were unaffected. To gain some evidence in possible involvement of prostaglandins system in diuretic action, the oral administration of HETM (300 mg/kg) in association indomethacin (5mg/kg) reduced the urinary and sodium excretion when compared only HETM group.

CONCLUSION

The results suggest that HETM could present compound(s) responsible for diuretic activities with no signs of toxicity, and the mechanism could involve prostaglandin system.