Potential immunomodulatory response associated with L-mimosine in male Wistar rats.

Leucaena leucocephala is a plant that is used as animal and human food worldwide. This plant contains the toxic compound namely L-mimosine. The main mechanism of action of this compound involves its ability to chelate metal ions, which may interfere with the proliferative activity of cells and being studied for the treatment of cancer. However, little is known about the effect of L-mimosine on immune responses. Thus, the aim of this study was to evaluate the effects of L-mimosine on immune responses in Wistar rats. Different doses of L-mimosine (25, 40 and 60 mg/kg body weight/day) were administered orally by gavage to adult rats for 28 days. No clinical signs of toxicity were observed in animals, but a decrease in the T-dependent response to sheep red blood cells (SRBC) in animals treated with 60 mg/kg L-mimosine and an increase in the intensity of S. aureus phagocytosis by macrophages in animals treated with 40 or 60 mg/kg L-mimosine were observed. Therefore, these findings suggest that L-mimosine did not compromise macrophage activity and inhibited T-dependent clonal expansion during the immune response.

Quantification of pyrrolizidine alkaloids in Senecio brasiliensis, beehive pollen, and honey by LC-MS/MS.

This article presents the determination of eight pyrrolizidine alkaloids (PAs) by LC-MS/MS in honeys, pollen, and Senecio brasiliensis (Asteraceae) samples, all from Santa Catarina state, Brazil. In addition, the Box-Behnken design was used to perform an optimized sample preparation on pollens and S. brasiliensis parts. Senecionine and its N-oxide, besides retrorsine N-oxide, were determined in six of the seven honeys samples. Pollen from species of the Asteraceae, Fabaceae, and Boraginaceae families were found with greater predominance in three of the seven honeys samples. In these three honeys samples were also found the highest PAs levels. In beehive pollen, flower, and leaf of S. brasiliensis, the total levels of PAs and their N-oxides reached 221, 14.1 × 104, and 14.8 × 104 mg kg-1, respectively. In honeys, these compounds are chemical contaminants and therefore undesirable when the sum exceeds 71 µg kg-1, according to EFSA. On the other hand, although PAs are naturally present in plant and pollen of some species (Senecio, Crotalaria, Bacharis, Ecchium, Mimosa scabrella, Vernonia), it is important to monitor their levels in plants but also in honeys, and other beehive products since these compounds are transferred to the final product.

The effect of Ipomoea carnea on maternal reproductive outcomes and fetal and postnatal development in rats.

Ipomoea carnea is a toxic plant found in Brazil and other tropical countries. The plant contains the alkaloids calystegines and swainsonine, which inhibit key cellular enzymes and cause systematic cell death. It is known that swainsonine is excreted in the amniotic fluid of dams exposed to the plant. Thus, the aim of this study was to verify whether the toxic effect of I. carnea on fetuses is due to exclusively the passage of the active principle of the plant through the placenta, or if the placentotoxic effect of swainsonine could collaborate in the adverse effects observed in the fetus. The teratogenic effects of exposure to the toxic principles of I. carnea were evaluated not only using the conventional protocol but also at later stages in the postnatal developmental period. Females were treated, from gestation day (GD) 6 until GD19, with 0.0, 1.0, 3.0 or 7.0 g/kg body weight of I. carnea dry leaves. The plant did not induce changes in reproductive performance or biochemical profile of the dams. Dams that received the highest dose of I. carnea showed cytoplasmic vacuolization in the liver, kidney and placental tissue. I. carnea promoted different lectin binding patterns in different areas of placental tissue. No fetal skeletal or visceral malformations was observed. The postnatal evaluation revealed a lower litter weight and a lower pup body weight one day after birth in the group that received the highest dose of I. carnea. Physical milestones were unaffected by the treatments. Female pups from all experimental groups exhibited a delay in achieving a negative geotaxis response. The results show that the toxic principle of I. carnea produces injury in utero in mothers and fetuses, but these deleterious effects were better demonstrated using postnatal evaluation.

The effect of Cynara scolymus (artichoke) on maternal reproductive outcomes and fetal development in rats.

Cynara scolymus (C.scolymus) is a plant employed worldwide as an herbal medicine. However, there is a paucity of data related to the evaluation of its toxicity in commercial preparations; thus, the aim of this study was to evaluate the possible teratogenic effect of the dry extract of C.scolymus leaves in Wistar rats. Females were treated, from gestation day (GD) 6 until GD19, with 0.0, 1.0, 2.0 or 4.0 g/kg body weight of C.scolymus extract. At GD20, a cesarean section was performed for evaluation of maternal and fetal parameters. C.scolymus did not induce changes in food consumption, preimplantation or postimplantation losses, placental weight or biochemical profile. An increase in water consumption was observed in pregnant females treated with the higher doses of C.scolymus. Experimental groups showed lower body weight gain during pregnancy and lower gravid uterus weight. Maternal body weight minus the gravid uterus weight did not result in significant differences. Reductions in fetal weight and length were observed in experimental groups. The number of live pups per litter was lower in the highest dose group. No fetal skeletal or visceral malformations were detected. The results showed that the consumption of artichoke during pregnancy clearly has a negative impact on fetuses.

Immunomodulatory effect of Cynara scolymus (artichoke) in rats.

Cynara scolymus is a plant used both as food as well as medicinal plant worldwide. Cynarin is one of the main active principles of the plant, and it is also present in species such as Echinacea purpurae, which is known to have immunomodulatory activity. Thus, the objective of this study is to evaluate the immune effects of C. scolymus in rats. Rats were treated with 1.0-, 2.0-, or 4.0-g/kg body weight of C. scolymus extract for 28 days. Haemogram, serum biochemistry, lymphoid organs weight, and their cell phenotypes were evaluated. Macrophages and neutrophils oxidative burst, specific humoral immune response, and the delayed-type hypersensitivity (DTH) were studied. No changes in the haemogram, biochemical profile, antibody titers, lymphoid organs, and in their cellularities were observed. An increase in the basal activity of reactive oxygen species from male's macrophage was observed. There was a suppression of the DTH response in both gender when treated with the highest dose of C. scolymus. This study is the first in the literature that revealed an immunosuppressive effect of C. scolymus. We also verified that the doses of artichoke extract here employed did not cause general toxicity.

Pfaffia paniculata (Brazilian ginseng) roots decrease proliferation and increase apoptosis but do not affect cell communication in murine hepatocarcinogenesis.

Pfaffia paniculata (Brazilian ginseng) roots and/or its extracts have shown anti-neoplastic, chemopreventive, and anti-angiogenic properties. The aim of this work was to investigate the chemopreventive mechanisms of this root in mice submitted to the infant model of hepatocarcinogenesis, evaluating the effects on cellular proliferation, apoptosis, and intercellular communication. Fifteen-day-old BALB/c male mice were given, i.p., 10mug/g of the carcinogen N-nitrosodiethylamine (DEN). Animals were separated into three groups at weaning and were given different concentrations of powdered P. paniculata root (0%, 2%, or 10%) added to commercial food for 27 weeks. Control group (CT) was not exposed to the carcinogen and was given ration without the root. After euthanasia, the animals' liver and body weight were measured. Liver fragments were sampled to study intercellular communication, molecular biology, and histopathological analysis. Cellular proliferation was evaluated by immunohistochemistry for PCNA, apoptosis was evaluated by apoptotic bodies count and alkaline comet technique, and intercellular communication by diffusion of lucifer yellow dye, immunofluorescence, western blot and real-time PCR for connexins 26 and 32. Chronic treatment with powdered P. paniculata root reduced cellular proliferation and increased apoptosis in the 2% group. Animals in the 10% group had an increase in apoptosis with chronic inflammatory process. Intercellular communication showed no alterations in any of the groups analyzed. These results indicate that chemopreventive effects of P. paniculata are related to the control of cellular proliferation and apoptosis, but not to cell communication and/or connexin expression, and are directly influenced by the root concentration.

Immunomodulatory effects of Pteridium aquilinum on natural killer cell activity and select aspects of the cellular immune response of mice.

Pteridium aquilinum (bracken fern) is one of the most common plants. Epidemiological studies have revealed a higher risk of certain types of cancers (i.e., esophageal, gastric) in people who consume bracken fern directly (as crosiers or rhizomes) or indirectly through the consumption of milk from livestock that fed on the plant. In animals, evidence exists regarding the associations between chronic bracken fern intoxication, papilloma virus infection, and the development of carcinomas. While it is possible that some carcinogens in bracken fern could be responsible for these cancers in both humans and animals, it is equally plausible that the observed increases in cancers could be related to induction of an overall immunosuppression by the plant/its various constituents. Under the latter scenario, normal tumor surveillance responses against nascent (non-bracken-induced) cancers or responses against viral infections (specifically those linked to induction of cancers) might be adversely impacted by continuous dietary exposure to this plant. Therefore, the overall objective of this study was to evaluate the immunomodulatory effects of bracken fern following daily ingestion of its extract by a murine host over a period of 14 (or up to 30) days. In C57BL/6 mice administered (by gavage) the extract, histological analyses revealed a significant reduction in splenic white pulp area. Among a variety of immune response parameters/functions assessed in these hosts and isolated cells, both delayed-type hypersensitivity (DTH) analysis and evaluation of IFNgamma production by NK cells during T(H)1 priming were also reduced. Lastly, the innate response in these hosts-assessed by analysis of NK cell cytotoxic functionality-was also diminished. The results here clearly showed the immunosuppressive effects of P. aquilinum and that many of the functions that were modulated could contribute to the increased risk of cancer formation in exposed hosts.

Cytotoxic effects of butanolic extract from Pfaffia paniculata (Brazilian ginseng) on cultured human breast cancer cell line MCF-7.

Roots of Pfaffia paniculata have been well documented for multifarious therapeutic values and have also been used for cancer therapy in folk medicine. This study has been performed in a human breast tumor cell line, the MCF-7 cells. These are the most commonly used model of estrogen-positive breast cancer, and it has been originally established in 1973 at the Michigan Cancer Foundation from a pleural effusion taken from a woman with metastatic breast cancer. Butanolic extract of the roots of P. paniculata showed cytotoxic effect MCF-7 cell line, as determined with crystal violet assay, cellular death with acridine orange/ethidium bromide staining, and cell proliferation with immunocytochemistry of bromodeoxyuridine (BrdU). Subcellular alterations were evaluated by electron microscopy. Cells treated with butanolic extract showed degeneration of cytoplasmic components and profound morphological and nuclear alterations. The results show that this butanolic extract indeed presents cytotoxic substances, and its fractions merit further investigations.

Pfaffia paniculata (Brazilian ginseng) methanolic extract reduces angiogenesis in mice.

Pfaffia paniculata (Brazilian ginseng) roots have been indicated for the treatment of several diseases. Our studies have shown that P. paniculata roots present antineoplastic effects and cancer chemopreventive activity in a mouse hepatocarcinogenesis model. The purpose of this study was to investigate the effects of the Brazilian ginseng on corneal angiogenesis in mice. We first conducted a toxicological study employing 250, 500, or 1000mg/kg/day of the methanolic extract of P. paniculata roots by gavage to BALB/c mice. Animals did not lose weight during the treatment nor presented histopathological alterations. The effect of this root on angiogenesis in the cornea of BALB/c mice was then assessed. Male mice were treated, by gavage, once a day, with doses of 250, 500, or 1000mg/kg of methanolic extract of P. paniculata powdered root for 10 days; filtered water was used as control. Corneal cauterization was accomplished by the contact of a silver nitrate crystal on the central area of the cornea, in the 5th day of treatment with P. paniculata, which continued thereafter; the animals were euthanized on the 6th day after cauterization. Newly formed blood vessels were filled with India ink, and the corneas were routinely processed. Blood vessels were quantified in an image analysis system. A smaller total area of neovascularization in the mouse cornea was observed in animals treated with 1000mg/kg of the methanolic extract of P. paniculata. These results indicate an antiangiogenic effect of this extract. The mechanisms of this antiangiogenic activity of P. paniculata should be further investigated.

Association of Ipomoea carnea and BCG reduces birth defects caused by cyclophosphamide in rats.

Immunosuppressive drugs can induce the development of malformations in fetuses of mothers exposed to them, possibly affecting the placental function directly or by crossing the placenta to enter fetal circulation. However, activation of the maternal immune system with well-known immunomodulator substances has been shown to produce a significant decrease in morphological defects caused by diverse teratogenic agents. All of these studies were performed on mice only, whereas the rat is the chosen species for developing teratological studies. Thus, the purpose of the present study was to investigate the possible protective effect of Bacillus Calmette Guérin (BCG) and/or the aqueous fraction (AF) of the plant Ipomoea carnea on the decrease of the teratogenic effect resulting from cyclophosphamide (CP), an antineoplastic and immunosuppressive drug, exposure in pregnant rats. It was verified that both BCG and/or AF attenuated the embryotoxic effects of CP in rats. All immune stimulated dams demonstrated an increase in placenta and fetus body weight. In conclusion, the present work showed that the rat is a good model for performing studies which aim for a clearer understanding of the mechanism by which maternal stimulation reduces malformations and how the association of I. carnea AF and BCG provided improved immunostimulation compared to BCG alone; however, additional studies are required to determine the specific mechanisms by which immune stimulant substances decrease malformation.

Antineoplastic effects of butanolic residue of Pfaffia paniculata.

We have previously reported a reduction in the accumulation of ascitic fluid in Ehrlich tumor-bearing mice following treatment with the powdered roots of Pfaffia paniculata. The aim of this study was to investigate which extracts from these roots presented antineoplastic properties. Thus, the effects of the ethanolic extract, butanolic residue, or aqueous residue from Pfaffia paniculata on animal survival and tumor growth in mice bearing this tumor were studied. Butanolic residue-treated mice survived longer than untreated mice. This result points to an antineoplastic effect exerted by the butanolic fraction from the roots of P. paniculata on this tumor model.

Identificação de princípios ativos presentes na Ipomoea carnea brasileira / Identification of Brazilian Ipomoea carnea toxic compounds

Dentre as espécies pertencentes à família das Convolvulceae destacam-se as Ipomoeas, amplamente distribuídas por todo o mundo, bastante conhecidas e cultivadas devido ao aspecto ornamental que suas flores campanuladas e de cores vibrantes oferecem. É sabido porém que espécies de Ipomoeas são tóxicas. A Ipomoea carnea, espécie de nosso estudo, provoca emagrecimento, apatia, incoordenção motora, fraqueza progressiva e até mesmo a morte em animais de produção, se ingerida por período prolongado. Os alcalóides suainsonina e calisteginas presentes nesta planta são certamente responsáveis por tais efeitos tóxicos, já que inibem a ação das manosidases e glicosidases, enzimas fundamentais para um adequado metabolismo de carboidratos pelo organismo...

Assessment of the perinatal effects of maternal ingestion of Solanum malacoxylon in rats.

A perinatal study was performed to verify the toxic effects of Solanum malacoxylon, which contains a glycoside conjugated to Vitamin D(3). In the gestational study, female rats received S. malacoxylon leaves in the diet at 0, 0.1, 0.2, 0.5, and 1% from days 6 to 21 of pregnancy. At 21 days of gestation, blood samples were taken from the dams for evaluation of serum Ca and P. A laparotomy was performed and the rats were examined for standard parameters of reproductive performance. Fetuses were examined for skeletal changes and histopathologic evaluation. In the second trial, dams were fed diets containing 0 or 0.1% S. malacoxylon leaves during the gestation and lactation periods. After weaning, all animals were euthanized and biochemical and histopathologic evaluations were performed. The biochemical evaluation showed increase in Ca and P levels in females from all experimental groups; however, this effect did not occurred in a dose-related manner. Pups from dams exposed during gestation and lactationi also showed increased Ca and P levels. Fetal data suggested a delay of fetal development manifested by decreased body weight and skeletal alterations. There was also a reduction in live fetuses. Histopathologic study revealed alterations of the soft tissue in litters from dams given 1% dietary S. malacoxylon during pregnancy and 0.1% during pregnancy and lactation. These findings support our hypothesis that Vitamin D(3) glycoside crosses the placenta and suggests milk transfer of this substance.