tannins and Plant-Poisoning

Proanthocyanidins (PA) (condensed tannins) and hydrolyzable tannins (HT) are the two major classes of tannins. Proanthocyanidins are flavonoid polymers. Hydrolyzable tannins are polymers of gallic or ellagic acid esterified to a core molecule, commonly glucose or a polyphenol such as catechin. Proanthocyanidins are the most common type of tannin found in forage legumes. Problems in the analysis of tannins are that sample processing and drying decrease extraction and reactivity, suitable standards are unavailable, and quantitative analytical methods are poorly correlated with enzyme inhibition, protein precipitation, and nutritional effects. Hydrolyzable tannins are potentially toxic to ruminants. Pyrogallol, a hepatotoxin and nephrotoxin, is a product of HT degradation by ruminal microbes. Proanthocyanidins are considered to be non-toxic because they are not absorbed, but they are associated with lesions of the gut mucosa. Research on tannins in forage legumes has determined their effects on protein digestion and metabolism but more research on tannin structure in relation to digestion of specific proteins is needed. The widely accepted explanation for positive effects of PA on protein digestion and metabolism is that PA-protein complexes escape ruminal degradation and the protein is available in the lower tract. This proposed mechanism may be incorrect because PA also complex carbohydrates, endogenous proteins, and microbial products and the degradability of PA-protein complexes by ruminal microbes has not been adequately studied. Several alternative hypotheses (to escape protein) that explain the effect of PA on protein digestion and metabolism in ruminants are also consistent with experimental results on forage legumes. These include increased microbial protein synthesis, increased use of endogenous nitrogen in the rumen, and increased secretion of salivary glycoproteins. Research on manipulating the content and type of PA in forage legumes is justified because they are associated with non-bloating legumes, lower soluble non-protein nitrogen in silage, and improved efficiency of protein utilization. Research on the biosynthesis, molecular genetics, and cell biology of PA in forage legumes needs to be integrated with research on toxicology and nutrition.

Topics: Animal Feed; Animals; Fabaceae; Flavonoids; Phenols; Plant Poisoning; Plants, Medicinal; Polymers; Polyphenols; Ruminants; Tannins

Most clinical problems due to plant exposures result from experimentation with or overt abuse of plant parts and extracts. Plant exposures may present as complex pharmacologic problems that challenge the diagnostic and therapeutic skills of the physician. Although specific physiologic antagonists (antidotes) may exist for specific intoxications, basic decontamination and supportive techniques are often all that may be offered.

Topics: Adult; Alkaloids; Autonomic Nervous System Diseases; Cardiovascular Diseases; Central Nervous System Diseases; Child; Child, Preschool; Dermatitis, Contact; Emergencies; Gastroenteritis; Glycosides; Hematologic Diseases; Humans; Kidney Diseases; Liver Diseases; Magnoliopsida; Oils; Plant Extracts; Plant Poisoning; Plants, Toxic; Resins, Plant; Tannins

Exposures to plants generate an exceptional amount of public concern, especially plant ingestions by children. Most clinical problems, however, involve older age groups as a result of experimentation with or overt abuse of plant parts and extracts. Of mounting concern is the sometimes uninformed and massive use of herbal preparations, currently widely available and in popular vogue. Plant exposures, from whatever source, may present as complex pharmacologic problems that may challenge the diagnostic and therapeutic skills of the physician. Although specific physiologic antagonists (antidotes) may exist for specific intoxications, basic decontamination and supportive techniques are many times all that may be offered.

Topics: Adult; Alkaloids; Cardiovascular Diseases; Child; Cyanides; Dermatitis, Contact; Emergencies; Female; Gastroenteritis; Glycosides; Hematologic Diseases; Humans; Kidney Diseases; Liver Diseases; Magnoliopsida; Male; Mouth Mucosa; Nervous System Diseases; Oils, Volatile; Plant Poisoning; Plants, Edible; Plants, Medicinal; Plants, Toxic; Resins, Plant; Tannins

The leaves of Acer rubrum (red maple), especially when wilted in the fall, cause severe oxidative damage to equine erythrocytes, leading to potentially fatal methemoglobinemia and hemolytic anemia. Gallic acid and tannins from A. rubrum leaves have been implicated as the toxic compounds responsible for red maple toxicosis, but the mechanism of action and toxic principle(s) have not been elucidated to date. In order to investigate further how red maple toxicosis occurs, aqueous solutions of gallic acid, tannic acid, and ground dried A. rubrum leaves were incubated with contents of equine ileum, jejunum, cecum, colon, and liver, and then analyzed for the metabolite pyrogallol, as pyrogallol is a more potent oxidizing agent. Gallic acid was observed to be metabolized to pyrogallol maximally in equine ileum contents in the first 24 hr. Incubation of tannic acid and A. rubrum leaves, individually with ileum contents, produced gallic acid and, subsequently, pyrogallol. Ileum suspensions, when passed through a filter to exclude microbes but not enzymes, formed no pyrogallol, suggesting a microbial basis to the pathway. Bacteria isolated from ileum capable of pyrogallol formation were identified as Klebsiella pneumoniae and Enterobacter cloacae. Therefore, gallotannins and free gallic acid are present in A. rubrum leaves and can be metabolized by K. pneumoniae and E. cloacae found in the equine ileum to form pyrogallol either directly or through a gallic acid intermediate (gallotannins). Identification of these compounds and their physiological effects is necessary for the development of effective treatments for red maple toxicosis in equines.

Topics: Acer; Animals; Enterobacter cloacae; Gallic Acid; Gastrointestinal Diseases; Horse Diseases; Horses; Klebsiella; Methemoglobinemia; Plant Leaves; Plant Poisoning; Pyrogallol; Tannins

Plants contain a variety of chemical defenses that strongly affect feeding rates in captive mammals, but their effects on the fitness of wild herbivores are largely unknown. This is because the complexity of defensive compounds, and herbivores' counteradaptations to them, make their effects in the wild difficult to measure. We show how tannins interact with protein to produce spatial variation in the nutritional quality of eucalypt foliage, which is related to demography in a wild population of a marsupial folivore, the common brushtail possum (Trichosurus vulpecula Kerr). Tannins reduced the digestibility of nitrogen (N) in vitro, creating variation in available N concentrations among the home ranges of individual possums in an otherwise homogeneous habitat. This was strongly correlated with reproductive success: females with better quality trees in their home range reproduced more often and had faster-growing offspring. These results demonstrate a powerful mechanism by which spatial variation in plant chemistry may control herbivore population dynamics in nature.

Topics: Analysis of Variance; Animal Nutritional Physiological Phenomena; Animals; Demography; Digestion; Eating; Ecosystem; Eucalyptus; Feeding Behavior; Female; Male; Marsupialia; Nitrogen; Plant Poisoning; Population Dynamics; Reproduction; Tannins; Trichosurus

Topics: Administration, Oral; Animals; Animals, Domestic; Lethal Dose 50; Male; Mice; Nitrates; Oxalates; Plant Poisoning; Plants, Toxic; Sterols; Tannins

Terminalia oblongata (yellow wood) is a small deciduous tree growing over an area of central Queensland that supports a large proportion of this state's cattle population. Cattle and sheep that consume yellow wood leaves are poisoned and die. Severe losses of these animals can occur, and this problem is considered the main cause of economic loss to the cattle industry in the area apart from drought. A new toxic condensed tannin, terminalin was isolated from Terminalia oblongata. Its structure was deduced following NMR, IR, UV, MS analyses and in the knowledge that these data show good correlations to those obtained from the related punicalagin molecule which is present in the plant. Terminalin has a high toxicity (20 mg/kg) to white Quackenbush male mice and produces a vascular renal necrosis with slight liver necrosis, unlike punicalagin, which produces liver lesions but not kidney lesions. Similar results were obtained with sheep. A most interesting aspect is that there are two different specific toxins in the plant.

Topics: Animals; Injections, Intraperitoneal; Kidney; Liver; Magnetic Resonance Spectroscopy; Male; Mice; Plant Extracts; Plant Poisoning; Proanthocyanidins; Queensland; Sheep; Sheep Diseases; Spectrometry, Mass, Fast Atom Bombardment; Spectrophotometry, Infrared; Tannins; Trees

Oak poisoning occurred in crossbred cattle due to eating immature tender oak (Quercus incana) leaves. Mortality was 70%. The animals exhibited anorexia, severe constipation and brisket edema. The feces were hard, pelleted and coated with blood and mucous. Significant reductions in blood hemoglobin and mean corpuscular hemoglobin, and significant elevations in serum bilirubin were observed. Serum urea nitrogen and creatinine were greatly increased. There was bilirubinuria, proteinuria, hypoproteinemia and hypocalcemia, and greatly increased activities of serum aspartate aminotransferase, lactate dehydrogenase and alkaline phosphatase. The levels of tannins and condensed tannins were 97.7 mg tannic acid equivalent and 5.8 mg catechin equivalent/g of dry leaves. There was extensive nephro- and hepatotoxicity in the affected cattle due to hydrolysable tannins and simple phenols in the oak leaves.

Topics: Anemia, Hemolytic; Animals; Anorexia; Blood Cells; Blood Chemical Analysis; Cattle; Cattle Diseases; Constipation; Edema; Feces; Hypothermia; Kidney Diseases; Liver Diseases; Phenols; Plant Poisoning; Polyuria; Tannins; Trees

Topics: Animals; Horse Diseases; Horses; Plant Poisoning; Tannins

Topics: Animals; Cattle; Cattle Diseases; Plant Poisoning; Seeds; Tannins

Topics: Animal Nutritional Physiological Phenomena; Animals; Kidney; Liver; Plant Poisoning; Plants; Sheep; Sheep Diseases; Tannins; Trees

Topics: Alkaloids; Animals; Flavonoids; Injections, Intraperitoneal; Injections, Intravenous; Male; Mice; Plant Extracts; Plant Poisoning; Plants; Saponins; Tannins

Topics: Benzoates; Herbicides; Peptic Ulcer; Plant Poisoning; Plants; Stomach Ulcer; Tannins