In vitro hematotoxicity of Vernonanthura polyanthes leaf aqueous extract and its fractions.

Vernonanthura polyanthes, popularly known as 'assa-peixe', is widely used in Brazil for therapeutic purpose mainly to treat respiratory tract problems. However, few studies investigated its chemical safety. In this way, we first obtained the V. polyanthes leaf aqueous extract (VpLAE) and three fractions (aqueous; n-butanol, n-BF; and ethyl acetate), and we chemically characterized this material. Then, the cytogenotoxic potential of the VpLAE and its fractions was investigated against human erythrocytes and lymphocytes using Trypan blue exclusion test of cell viability and CometChip. The phytochemical screening of V. polyanthes leaf revealed the presence of total phenolic compounds, flavonoids, tannins, coumarins, terpenic compounds, and cardioactive heterosides. n-BF presented the highest total phenolic, flavonoids, and tannins contents and, consequently, the highest antioxidant activity, according to the DPPH free radical scavenging method. Although the VpLAE and its fractions did not cause death of erythrocytes, the cells acquired an echinocytic form. Regarding lymphocytes, VpLAE and its fractions presented cytotoxicity and genotoxicity. When VpLAE or its fractions were co-treated with doxorubicin (DXR), a recognized cytotoxic drug, we observed an enhancement of DXR cytotoxicity against lymphocytes, but the DXR genotoxicity decreased around 15%. Since the VpLAE and its fractions increased the DXR cytotoxicity and decreased its genotoxicity, further studies should be conducted for the development of an adjuvant drug from this extract to reduce the side effects of chemotherapy. Moreover, the indiscriminate use of 'assa-peixe' by local people should be discouraged.

Universal Antifouling and Photothermal Antibacterial Surfaces Based on Multifunctional Metal-Phenolic Networks for Prevention of Biofilm Formation.

Biofilms formed from the pathogenic bacteria that attach to the surfaces of biomedical devices and implantable materials result in various persistent and chronic bacterial infections, posing serious threats to human health. Compared to the elimination of matured biofilms, prevention of the formation of biofilms is expected to be a more effective way for the treatment of biofilm-associated infections. Herein, we develop a facile method for endowing diverse substrates with long-term antibiofilm property by deposition of a hybrid film composed of tannic acid/Cu ion (TA/Cu) complex and poly(ethylene glycol) (PEG). In this system, the TA/Cu complex acts as a multifunctional building block with three different roles: (i) as a versatile "glue" with universal adherent property for substrate modification, (ii) as a photothermal biocidal agent for bacterial elimination under irradiation of near-infrared (NIR) laser, and (iii) as a potent linker for immobilization of PEG with inherent antifouling property to inhibit adhesion and accumulation of bacteria. The resulted hybrid film shows negligible cytotoxicity and good histocompatibility and could prevent biofilm formation for at least 15 days in vitro and suppress bacterial infection in vivo, showing great potential for practical applications to solve the biofilm-associated problems of biomedical materials and devices.

The Effects of Tannins in Monogastric Animals with Special Reference to Alternative Feed Ingredients.

Over recent years, the monogastric animal industry has witnessed an increase in feed prices due to several factors, and this trend is likely to continue. The hike in feed prices is mostly due to extreme competition over commonly used conventional ingredients. For this trend to be subdued, alternative ingredients of both plant and animal origin need to be sourced. These types of ingredients are investigated with the aim of substituting all or some of the conventional compounds. However, alternative ingredients often have a double-edged sword effect, in that they can supply animals with the necessary nutrients although they contain antinutritional factors such as tannins. Tannins are complex secondary metabolites commonly present in the plant kingdom, known to bind with protein and make it unavailable; however, recently they have been proven to have the potential to replace conventional ingredients, in addition to their health benefits, particularly the control of zoonotic pathogens such as Salmonella. Thus, the purpose of this review is to (1) classify the types of tannins present in alternative feed ingredients, and (2) outline the effects and benefits of tannins in monogastric animals. Several processing methods have been reported to reduce tannins in diets for monogastric animals; furthermore, these need to be cost-effective. It can thus be concluded that the level of inclusion of tannins in diets will depend on the type of ingredient and the animal species.

Bioresponsive supramolecular hydrogels for hemostasis, infection control and accelerated dermal wound healing.

Injectable, drug-releasing hydrogel scaffolds with multifunctional properties including hemostasis and anti-bacterial activity are essential for successful wound healing; however, designing ideal materials is still challenging. Herein, we demonstrate the fabrication of a biodegradable, temperature-pH dual responsive supramolecular hydrogel (SHG) scaffold based on sodium alginate/poly(N-vinyl caprolactam) (AG/PVCL) through free radical polymerization and the subsequent chemical and ionic cross-linking. A natural therapeutic molecule, tannic acid (TA)-incorporated SHG (AG/PVCL-TA), was also fabricated and its hemostatic and wound healing efficiency were studied. In the AG/PVCL-TA system, TA acts as a therapeutic molecule and also substitutes as an effective gelation binder. Notably, the polyphenol-arm structure and diverse bonding abilities of TA can hold polymer chains through multiple bonding and co-ordinate cross-linking, which were vital in the formation of the mechanically robust AG/PVCL-TA. The SHG formation was successfully balanced by varying the composition of SA, VCL, TA and cross-linkers. The AG/PVCL-TA scaffold was capable of releasing a therapeutic dose of TA in a sustained manner under physiological temperature-pH conditions. AG/PVCL-TA displayed excellent free radical scavenging, anti-inflammatory, anti-bacterial, and cell proliferation activity towards the 3T3 fibroblast cell line. The wound healing performance of AG/PVCL-TA was further confirmed in skin excision wound models, which demonstrated the potential application of AG/PVCL-TA for skin regeneration and rapid wound healing.

Beneficial effects of water-soluble chestnut (Castanea sativa Mill.) tannin extract on chicken small intestinal epithelial cell culture.

Feed and water supplementation with powdered hydrolyzable tannins from chestnut represents a valuable alternative strategy to antibiotics in animal nutrition. In this study, we evaluated the effects and safety of a water-soluble form of chestnut tannin (WST) in an in vitro model of chicken small intestinal epithelial cells (CSIEC). A chicken cell culture was established, and WST in concentrations of 0.025, 0.05, 0.1, and 0.2% were tested for cytotoxicity, cell proliferation, metabolic activity, production of reactive oxygen species, intracellular antioxidative potential, genotoxicity, and influence on the epithelia cell cycle. The tested concentrations showed a significant (P < 0.05) greater proliferative effect on CSIEC than the control medium (maximal proliferation at 0.1% WST as determined by optical density measurements). The 0.2% concentration of WST was cytotoxic, causing significantly higher (P < 0.05) nitric oxide and hydrogen peroxide production but with no short-term genotoxicity. Although increasing the concentration caused a decline in the metabolism of challenged cells (the lowest at 0.1% WST), metabolic activity remained higher than that in control cells. The antioxidant potential was 75% better and significantly (P < 0.05) higher in the 0.1% WST cultured cells compared to control. In conclusion, the cultured CSIEC are useful tools in basic and clinical research for the study of intestinal physiology, as they retain physiological and biochemical properties and epithelial morphology close to the original tissue and, in many ways, reflect the in vivo state. Our results indicate that WST exert a beneficial effect on intestinal epithelia, since they: i) stimulate proliferation of enterocytes; ii) increase antioxidative potential; iii) have no genotoxic effect; and iv) do not affect cellular metabolism. Our results reinforce the importance of WST as promising candidates for further evaluation and use in commercial broiler farm production.

Synthesis and Application of a New Amphiphilic Antioxidant.

A new amphiphilic antioxidant (tannyl stearate) derived from reaction of tannic acid with stearic acid was synthesized in order to improve tannic acid solubility in lipid materials. This reaction gives many products having different degree of esterification (tannyl mono, di, tri, tetra, penta, hexa, hepta……stearate) which were separated using silica gel column chromatography and tentative identification was carried out using thin layer chromatography (TLC). The intrinsic viscosities (η) were used to differentiate between the different molecular weight of the produced esters1). Tannyl penta stearate is assumed to be the most suitable amphiphilic antioxidant derivative, where those derivatives with less degree of esterification would be less soluble in fat, and those of higher degree of esterification would exhaust more hydroxyl group that cause decreases of antioxidant activity. The structure of tannyl penta stearate was approved depending on its chemical analysis and spectral data (IR, H1 NMR,). The emulsification power of tannyl penta stearate was then determined according to method described by El-Sukkary et al.2), in order to prove its amphiphilic property. Then tannyl penta stearate was tested for its antioxidant and radical scavenging activities in three different manners, those are, lipid oxidation in sunflower oil using Rancimat, (DPPH) free radical scavenging and total antioxidant activity. {Pure tannic acid (T), butylhydroxyanisol (BHA) and butylhydroxytoluene (BHT) were used as reference antioxidant radical saving compounds}. Then tannyl penta stearate was added to sunflower oil, frying process was carried out and all physicochemical parameters of the oil were considered, and compared to other reference antioxidant in order to study the effect of this new antioxidant toward oil stability. Acute oral toxicity of the tannyl penta stearate was carried out using albino mice of 21-25 g body weight to determine its safety according to the method described by Goodman et al.3). Also liver and kidney functions of those mice were checked. Thus it could be concluded that the addition of tannyl penta stearate to frying oils offers a good protection against oxidation. The effectiveness of tannyl penta stearate as lipid antioxidant has been attributed mainly to its stability at high temperature. And according to acute lethal toxicity test tannyl penta stearate was found to be a safe compound that can be used as food additive.

Phytochemical Screening and Acute Toxicity of Aqueous Extract of Leaves of Conocarpus erectus Linnaeus in Swiss Albino Mice.

Mangroves represent areas of high biological productivity and it is a region rich in bioactive substances used in medicine production. Conocarpus erectus (Combretaceae) known as button mangrove is one of the species found in mangroves and it is used in folk medicine in the treatment of anemia, catarrh, conjunctivitis, diabetes, diarrhea, fever, gonorrhea, headache, hemorrhage, orchitis, rash, bumps and syphilis. The present study aimed to investigate the acute toxicity of aqueous extract of leaves of C. erectus in Swiss albino mice. The plant material was collected in Vila Velha mangroves, located in Itamaracá (PE). The material was subjected to a phytochemical screening where extractive protocols to identify majority molecules present in leaves were used. The evaluation of acute toxicity of aqueous extract of C. erectus followed the model of Acute Toxicity Class based on OECD 423 Guideline, 2001. The majority molecules were identified: flavonoids, tannins and saponins. The LD50 was estimated at 2,000 mg/kg bw. Therefore, the aqueous extract showed low acute toxicity classified in category 5.

Cytotoxicity potentials of eleven Bangladeshi medicinal plants.

Various forms of cancer are rising all over the world, requiring newer therapy. The quest of anticancer drugs both from natural and synthetic sources is the demand of time. In this study, fourteen extracts of different parts of eleven Bangladeshi medicinal plants which have been traditionally used for the treatment of different types of carcinoma, tumor, leprosy, and diseases associated with cancer were evaluated for their cytotoxicity for the first time. Extraction was conceded using methanol. Phytochemical groups like reducing sugars, tannins, saponins, steroids, gums, flavonoids, and alkaloids were tested using standard chromogenic reagents. Plants were evaluated for cytotoxicity by brine shrimp lethality bioassay using Artemia salina comparing with standard anticancer drug vincristine sulphate. All the extracts showed potent to moderate cytotoxicity ranging from LC50 2 to 115 µg/mL. The highest toxicity was shown by Hygrophila spinosa seeds (LC50 = 2.93 µg/mL) and the lowest by Litsea glutinosa leaves (LC50 = 114.71 µg/mL) in comparison with standard vincristine sulphate (LC50 = 2.04 µg/mL). Among the plants, the plants traditionally used in different cancer and microbial treatments showed highest cytotoxicity. The results support their ethnomedicinal uses and require advanced investigation to elucidate responsible compounds as well as their mode of action.

Inactivation of pathogenic viruses by plant-derived tannins: strong effects of extracts from persimmon (Diospyros kaki) on a broad range of viruses.

Tannins, plant-derived polyphenols and other related compounds, have been utilized for a long time in many fields such as the food industry and manufacturing. In this study, we investigated the anti-viral effects of tannins on 12 different viruses including both enveloped viruses (influenza virus H3N2, H5N3, herpes simplex virus-1, vesicular stomatitis virus, Sendai virus and Newcastle disease virus) and non-enveloped viruses (poliovirus, coxsachievirus, adenovirus, rotavirus, feline calicivirus and mouse norovirus). We found that extracts from persimmon (Diospyros kaki), which contains ca. 22% of persimmon tannin, reduced viral infectivity in more than 4-log scale against all of the viruses tested, showing strong anti-viral effects against a broad range of viruses. Other tannins derived from green tea, acacia and gallnuts were effective for some of the viruses, while the coffee extracts were not effective for any of the virus. We then investigated the mechanism of the anti-viral effects of persimmon extracts by using mainly influenza virus. Persimmon extracts were effective within 30 seconds at a concentration of 0.25% and inhibited attachment of the virus to cells. Pretreatment of cells with the persimmon extracts before virus infection or post-treatment after virus infection did not inhibit virus replication. Protein aggregation seems to be a fundamental mechanism underlying the anti-viral effect of persimmon tannin, since viral proteins formed aggregates when purified virions were treated with the persimmon extracts and since the anti-viral effect was competitively inhibited by a non-specific protein, bovine serum albumin. Considering that persimmon tannin is a food supplement, it has a potential to be utilized as a safe and highly effective anti-viral reagent against pathogenic viruses.

Toxicidad crónica de polvo de taninos obtenidos de corteza de Pinus caribaea Morelet por vía oral en ratas / Chronic oral toxicity of tannin powders obtained from bark of Pinus caribaea Morelet in rats

INTRODUCCIÓN: se han demostrado los efectos antimutagénicos y no genotóxicos de los taninos de Pinus caribaea Morelet, así como su influencia en la mejoría de la calidad de vida de pacientes. OBJETIVOS: evaluar la toxicidad crónica del polvo de taninos obtenido de corteza de P. caribaea por vía oral. MÉTODOS: se realizó un estudio de toxicidad crónica (6 meses) por vía oral en ratas Cenp:SPRD. Se conformaron un grupo control y 3 tratados (1, 2,5 y 5 mg/kg/d/6 meses). Se realizaron observaciones clínicas diarias. El peso corporal y los consumos de agua y alimento se midieron semanalmente. Al inicio, en la semana 13 y al final del estudio se realizaron exámenes de laboratorio clínico. Al concluir los 6 meses se sacrificaron todos los animales y se efectuó necropsia completa de cada uno, así como el estudio microscópico de los órganos y tejidos de los animales de los grupos Dosis alta y control. RESULTADOS: durante el estudio murió 1 hembra del gurpo Dosis baja, el resto de los animales alcanzó el final del estudio con buen estado. Los signos clínicos descritos estuvieron distribuidos por todos los grupos y no guardaron relación con la sustancia de ensayo. La curva de peso corporal fue similar para todos los grupos. El consumo de agua se incrementó en los animales tratados con la dosis mayor, el consumo de alimento no se vio afectado. Los parámetros de laboratorio clínico presentaron diferencias, aunque se mantuvieron dentro de los rangos normales reportados para la especie. Los hallazgos de anatomía patológica no guardaron relación con la administración del polvo de taninos. CONCLUSIONES: la administración oral durante 6 meses del polvo de taninos de corteza de P. caribaea no produjo toxicidad(AU)

INTRODUCTION: effects of antimutagenic and non-genotoxic agents of tannins from Pinus caribaea Morelet, as well as its influence in improvement of quality life of patients. OBJECTIVES: to assess chronic oral toxicity of tannin powder obtained from bark of P. caribaea. METHODS: we performed a study on chronic toxicity (6 months) per os in Cenp:SPRD rats. We made clinical observations daily. There was a control group and 3 treated (1, 2, 5 and 5 mg/kg/d/6 months). We performed clinical observations daily. Body weight and water and food consumptions were measured weekly. At the beginning, in 13 week and at the end of study, we carried out clinical laboratory examinations. At 6 months all animals were scarified and we made a complete necropsy of each, as well as a microscopical study of organs and tissues of animals in groups of higher dose and control. RESULTS: during study a female in lower dose group died, the remainder finished the study in a good sate. Clinical signs described were distributed by all groups and had not relation with assay substance. Body weight curve was similar for all groups. Water consumption increased in animals treated with the higher dose, but the food consumption was normal. Clinical laboratory parameters had differences, although they were within normal ranks reported for the species. Findings of pathologic anatomy have not relation to administration of tannin powders. CONCLUSIONS: There was not toxicity with per os administration during 6 months of tannin powders from bark of P. caribaea(AU)

Toxicidad crónica de polvo de taninos obtenidos de corteza de Pinus caribaea Morelet por vía oral en ratas / Chronic oral toxicity of tannin powders obtained from bark of Pinus caribaea Morelet in rats

INTRODUCCIÓN: se han demostrado los efectos antimutagénicos y no genotóxicos de los taninos de Pinus caribaea Morelet, así como su influencia en la mejoría de la calidad de vida de pacientes. OBJETIVOS: evaluar la toxicidad crónica del polvo de taninos obtenido de corteza de P. caribaea por vía oral. MÉTODOS: se realizó un estudio de toxicidad crónica (6 meses) por vía oral en ratas Cenp:SPRD. Se conformaron un grupo control y 3 tratados (1, 2,5 y 5 mg/kg/d/6 meses). Se realizaron observaciones clínicas diarias. El peso corporal y los consumos de agua y alimento se midieron semanalmente. Al inicio, en la semana 13 y al final del estudio se realizaron exámenes de laboratorio clínico. Al concluir los 6 meses se sacrificaron todos los animales y se efectuó necropsia completa de cada uno, así como el estudio microscópico de los órganos y tejidos de los animales de los grupos Dosis alta y control. RESULTADOS: durante el estudio murió 1 hembra del gurpo Dosis baja, el resto de los animales alcanzó el final del estudio con buen estado. Los signos clínicos descritos estuvieron distribuidos por todos los grupos y no guardaron relación con la sustancia de ensayo. La curva de peso corporal fue similar para todos los grupos. El consumo de agua se incrementó en los animales tratados con la dosis mayor, el consumo de alimento no se vio afectado. Los parámetros de laboratorio clínico presentaron diferencias, aunque se mantuvieron dentro de los rangos normales reportados para la especie. Los hallazgos de anatomía patológica no guardaron relación con la administración del polvo de taninos. CONCLUSIONES: la administración oral durante 6 meses del polvo de taninos de corteza de P. caribaea no produjo toxicidad.

INTRODUCTION: effects of antimutagenic and non-genotoxic agents of tannins from Pinus caribaea Morelet, as well as its influence in improvement of quality life of patients. OBJECTIVES: to assess chronic oral toxicity of tannin powder obtained from bark of P. caribaea. METHODS: we performed a study on chronic toxicity (6 months) per os in Cenp:SPRD rats. We made clinical observations daily. There was a control group and 3 treated (1, 2, 5 and 5 mg/kg/d/6 months). We performed clinical observations daily. Body weight and water and food consumptions were measured weekly. At the beginning, in 13 week and at the end of study, we carried out clinical laboratory examinations. At 6 months all animals were scarified and we made a complete necropsy of each, as well as a microscopical study of organs and tissues of animals in groups of higher dose and control. RESULTS: during study a female in lower dose group died, the remainder finished the study in a good sate. Clinical signs described were distributed by all groups and had not relation with assay substance. Body weight curve was similar for all groups. Water consumption increased in animals treated with the higher dose, but the food consumption was normal. Clinical laboratory parameters had differences, although they were within normal ranks reported for the species. Findings of pathologic anatomy have not relation to administration of tannin powders. CONCLUSIONS: There was not toxicity with per os administration during 6 months of tannin powders from bark of P. caribaea.

[Technology of eliminating tannin with polyamide-adsorption for preparing Xinshao lyophilization].

OBJECTIVE: To study the process of eliminating tannin with polyamide-adsorption for preparing Xinshao lyophilyzation. METHOD: The transfer rate of paeoniflorin, tannin examination, the test of the local stimulus and abnormal toxicity on mice were adopted as indexes to optimize the process of tannin adsorption and resolution of polyamide-adsorption, and the effect of eliminating tannin of polyamide-adsorption was compared with traditional methods. RESULT: The effect of eliminating tannin with polyamide-adsorption was good, and the transfer rate of paeoniflorin with polyamide-adsorption was superior to the other methods. Furthermore, the abnormal toxicity decreased evidently and the security of the preparation was ensured. CONCLUSION: The method of polyamide-adsorption provides a useful reference to the technique of eliminating tannin in the traditional Chinese medicine injections.

Mutagenicity of Mouriri pusa Gardner and Mouriri elliptica Martius.

Mouriri pusa Gardner and Mouriri elliptica Martius are fruit-bearing plants of the Melastomataceae family, popularly known in Brazil as puçá-preto or jaboticaba-do-cerrado, and they are used in folk medicine for the treatment of gastric ulcers. In this study, we employ the Ames test to assess the mutagenicity of compounds obtained from the leaves of these species. The methanol extract of the M. pusa was mutagenic to the Salmonella typhimurium strains TA98, TA97a and TA100, with or without metabolic activation. The methanol extract of M. elliptica induced mutagenic activity in TA98 when metabolized with S9 fraction and TA97a with and without S9, but with lower mutagenicity index (MI) and potencies values than those for M. pusa. Enriched fractions of flavonoids and tannins of M. pusa were also evaluated and they demonstrated positive mutagenicity. The highest values of MI and potency were obtained with the flavonoid fraction, which contains large amounts of quercetin, quercetin glycosides and myricetin. These compounds are probably related to the mutagenicity observed in the Ames test. The dichloromethane extract was not mutagenic in any of the test conditions employed.

Antiulcerogenic effect and acute toxicity of a hydroethanolic extract from the cashew (Anacardium occidentale L.) leaves.

The antiulcerogenic effect of a hydroethanolic extract of Anacardium occidentale L. leaves was investigated. The extract inhibited gastric lesions induced by HCl/ethanol in female rats. A dose-response effect study showed that the ED50 was 150 mg/kgb.w. Extract doses higher than 100 mg/kgb.w. were more effective than 30 mg/kg of lansoprazol in inhibiting gastric lesions. A methanolic fraction (257.12 mg/kg) which reduced gastric lesion at 88.20% is likely to contain the active principle of the antiulcer effect. No signs of acute toxicity were observed when mice were treated with extract dose up to 2000 mg/kgb.w. A chemical analysis of the extract allowed the identification of phenolic compounds as the major components. Glycosylated quercetin, amentoflavone derivate and a tetramer of proanthocyanidin were identified by liquid chromatography coupled to mass spectrometry. The level of total phenolics in the extract was evaluated at 35.5% and flavonoid content was 2.58%.

Tannins from barks of Pinus caribaea protect Escherichia coli cells against DNA damage induced by gamma-rays.

This work was aimed to evaluate genotoxicity and antigenotoxicity activity against gamma-rays of a tannin fraction obtained from barks of Pinus caribaea, as well as to elucidate the antigenotoxic mechanisms involved in radioprotection by using different approaches as pre-, co- and post-irradiation cell treatments with plant extract. The tannin fraction was not genotoxic to Escherichia coli cells in experiments using different exposure times. This extract was antigenotoxic against gamma-rays when the cells were pre- or co-treated with this extracts, but not during post-irradiation treatments, suggesting a possibly antigenotoxic action through free radical scavenging mechanisms. The results are discussed in relation to the chemopreventive and therapeutic potential of the studied plant species.

Toxicidad de un extracto tánico de Pinus caribaea Morelet / Toxicity of a tanin extract from Pinus caribea Morelet

Se determinó la toxicidad aguda oral, dérmica y toxicogenética de un polvo de taninos obtenido a partir de un extracto acuoso de la corteza de Pinus caribaea Morelet secado por spray dry. En todos los casos se emplearon ratas Wistar de ambos sexos y peso corporal entre 150 y 200 g. Se empleó el ensayo de dosis límite y aplicación cutánea de parche oclusivo durante 24 h, para determinar la toxicidad aguda oral y dérmica, respectivamente. El polvo fue administrado en dosis de 2 000 mg/kg en ambas ocasiones. Después de 14 días de observación, los animales fueron sacrificados para realizarles autopsia y examen macroscópico de órganos y tejidos. El estudio toxicogenético se realizó en un modelo in vitro: el sistema Salmonella/microsoma (Ames) y otro in vivo: el ensayo de inducción de micronúcleos en médula ósea de ratón. En el ensayo de Ames se testaron las cepas TA 100, TA 98, TA 1535 y TA 1537 de Salmonella typhimurium con y sin activación metabólica en el rango de concentraciones de 50, 150, 500, 1 500 y 5 000 mg/placa. En el ensayo de inducción de micronúcleos se ensayaron dosis de 500, 1 000 y 2 000 mg/kg de peso corporal. Se comprobó que el polvo de taninos, obtenido a partir de un extracto acuoso de corteza de Pinus caribaea secado por spray dry, no es tóxico por administración oral y dérmica en los animales y es genotóxico in vitro e in vivo. Sería útil realizar otros estudios, con otras condiciones, para precisar la genotoxicidad de esta preparación(AU)

Antibacterial activity of hydrolyzable tannins derived from medicinal plants against Helicobacter pylori.

Helicobacter pylori is a major etiological agent in gastroduodenal disorders. In this study, we isolated 36 polyphenols and 4 terpenoids from medicinal plants, and investigated their antibacterial activity against H. pylori in vitro. All hydrolyzable tannins tested demonstrated promising antibacterial activity against H. pylori. Monomeric hydrolyzable tannins revealed especially strong activity. Other compounds demonstrated minimal antibacterial activity with a few exceptions. A monomeric hydrolyzable tannin, Tellimagrandin I demonstrated time- and dose-dependent bactericidal activity against H. pylori in vitro. On the other hand, hydrolyzable tannins did not affect the viability of MKN-28 cells derived from human gastric epithelium. Hydrolyzable tannins, therefore, have potential as new and safe therapeutic regimens against H. pylori infection. Furthermore, we investigated effects of hydrolyzable tannins on lipid bilayer membranes. All the hydrolyzable tannins tested demonstrated dose-dependent membrane-damaging activity. However, it remains to be elucidated whether their membrane-damaging activity directly contributes to their antibacterial action.

Mitochondrial dysfunction as an early event in the process of apoptosis induced by woodfordin I in human leukemia K562 cells.

Tannins are a group of widely distributed plant polyphenols, some of which are beneficial to health because of their chemopreventive activities. In the present study, we investigated the effects and action mechanisms of woodfordin I, a macrocyclic ellagitannin dimer, on human chronic myelogenous leukemia (CML) K562 cells. The results showed that woodfordin I was able to suppress the proliferation and induce apoptosis in K562 cells. Apoptosis was evaluated by cytomorphology, internucleosomal DNA fragmentation, and externalization of phosphatidylserine. Woodfordin I treatment caused a rapid and sustained loss of mitochondrial transmembrane potential (MMP), transient generation of reactive oxygen species (ROS), transient elevation of intracellular Ca2+ concentration, and cytosolic accumulation of cytochrome c. The activation of caspase-9 and 3, but not caspase-8, was also demonstrated, indicating that the apoptotic signaling triggered by woodfordin I was mediated through the intrinsic mitochondria-dependent pathway. Western blot and immunofluorescence analysis revealed that the anti-apoptotic Bcl-2 and Bcl-xL levels were downregulated, together with the pro-apoptotic Bax protein. Significantly, woodfordin I-induced apoptosis was associated with a decline in the levels of c-Abl, Bcr-Abl, and cellular protein tyrosine phosphorylation. Considering the consequence of all the events in the process of woodfordin I-induced apoptosis, the mitochondrial dysfunction is directly responsible for the pro-apoptotic effects on K562 cells. Furthermore, because CML is a malignancy of pleuripotent hematopoietic cells caused by the dysregulated tyrosine kinase activity of Bcr-Abl, these findings suggest that woodfordin I may be a potential lead compound against CML.

Intoxication of sheep with quebracho tannin extract.

This experiment was carried out to study the toxicity of quebracho tannin extract (containing 760 g of condensed tannins [CTs] per kg), with the aim of validating its use as a feed additive for improving the digestive utilization of protein-rich feeds. Four groups (Q(0), Q(1), Q(2) and Q(3)) of four sheep were dosed intra-ruminally once daily, for up to 21 days with, respectively, 0, 0.5, 1.5 or 3.0 g quebracho tannin extract/kg live-weight (LW). Feed intake, live-weight changes, plasma biochemistry, indicators of hepatic detoxification function, gross lesions and histopathology were examined. Animals in groups Q(0), Q(1) and Q(2) consumed all the offered feed. In contrast, feed intake was practically nil after 6 days of quebracho dosing in group Q(3), this being associated with a loss of 4.7+/-1.30 kg LW in 10 days (P<0.05). Sheep from groups Q(0), Q(1) and Q(2) remained healthy throughout the experiment. Ewes from group Q(3) became weak and depressed on day 5 and after 8 days of dosing remained recumbent. They were humanely killed after 10 days to avoid suffering. In general, neither gross lesions nor microscopical changes were observed in animals from groups Q(0), Q(1) and Q(2). However, Q(3) sheep showed striking lesions in the digestive tract (well-demarcated ulcers filled with necrotic material in the mucosa of the rumen and reticulum, distension of abomasum and small intestine, and dense mucous material in the caecum), and changes in plasma biochemistry. Cytochrome P-450 and glutathione concentrations were significantly reduced in Q(3) sheep (P<0.05). It is concluded that quebracho tannin extract is not toxic for ruminants, except in concentrations too high to be encountered under practical conditions.