chlorophyll-a and phytoporphyrin

Photosensitization is severe dermatitis or oxidative/chemical changes in the epidermal tissues activated by the light-induced excitation of molecules within the tissue. It is a series of reactions mediated through light receptors and is more common when the plant-produced metabolites are heterocyclic/polyphenols in nature. The areas affected are exposed body parts and mostly non-pigmented areas with least ultraviolet protection. Similarly, cellular alteration also occurs in the affected animal's dermal tissues and body parts and grazing animals by the accumulation and activation of photodynamic molecules. Photo-oxidation can also occur within the plant due to the generation of reactive oxygen species causing damage and degradation in the form of free radicals and DNA. During the last few decades, many new tropical grass species have been introduced in the grazing lands which are genetically modified, and the animals grazing on them are facing various forms of toxicity including photosensitization. The plant's secondary metabolites/drugs may cause toxicity when bacteria, viral agents, fungi (Pithomyces chartarum), or neoplasia injures the liver and prevents the phylloerythrin excretion. All these may disturb the liver enzymes and blood profile causing a decrease in weight and production (wool and milk etc.) with severe dermal, digestive, and nervous problems. Recent advancements in OMICS (cellomics, ethomics, metabolomics, metabonomics, and glycomics) have enabled us to detect and identify the plants' secondary metabolites and changes in the animal's physiology and histopathology as a causative of photosensitivity. The review focuses on types of photosensitization, reasons, secondary metabolic compounds, chemistry, and environmental effect on plants.

Topics: Animals; Cattle; Chlorophyll; Climate; DNA; Herbivory; Inflammation; Light; Liver; Oxygen; Photosensitivity Disorders; Pigmentation; Plants; Poaceae; Skin

Various hepatogenous photosensitivity diseases of ruminants in South Africa, caused by plants, fungi and an alga, are described. Information is given on botanical, mycological, toxicological, clinical and pathological aspects of the diseases. The intoxications were grouped according to the primary site of involvement and type of lesions in the liver. The aetiology, pathogenesis, and diagnosis of these conditions received special attention and the most important features are illustrated in colour.

Topics: Animals; Bile Ducts; Cattle; Cattle Diseases; Chemical Phenomena; Chemistry; Chlorophyll; Liver; Liver Diseases; Mushroom Poisoning; Photosensitivity Disorders; Plant Poisoning; Plants, Toxic; Sheep; Sheep Diseases; South Africa; Sporidesmins

Alveld is a disease in lambs of domestic sheep (Ovis aries L.), characterized by a combination of photosensitivity and liver damage. Generation of singlet oxygen play a major role in phototoxicity reactions. The compound phylloerythrin (phytoporphyrin) is so far assumed to be the main photodynamic agent in hepatogenous photosensitivity diseases in sheep. Phylloerythrin is a potent photosensitizer and an efficient source of singlet oxygen. The compound accumulates in the peripheral circualtion upon liver damage. Liver dysfunction is also likely to cause an increase in the blood level of bilirubin. Formation of singlet oxygen by bilirubin is reported. In the present work the photosensitizing potential of serum has been measured and related to the bilirubin- and phylloerythrin levels in lambs suffering from alveld and in clinically healthy controls. The singlet oxygen level of the serum was taken as a measure of the photosensitizing potential. The observed singlet oxygen values in serum from alveld lambs were significantly higher than the corresponding values observed in clinically healthy control lambs. This indicates that the serum of the alveld lambs contains an elevated concentration of photosensitizer. The singlet oxygen level was not correlated to the concentration of bilirubin or phylloerythrin. The results indicate that the photosensitizing mechanism is quite complex and may involve other sensitizer(s) than phylloerythrin.

Topics: Animals; Bilirubin; Chlorophyll; Jugular Veins; Liliaceae; Liver Diseases; Photosensitivity Disorders; Plant Poisoning; Reference Values; Sheep; Sheep Diseases; Singlet Oxygen; Spectrometry, Fluorescence

To validate a spectrofluorometric method for measuring chlorophyll a metabolites, specifically phytoporphyrin (= phylloerythrin), as well as the chlorins, pheophorbide a and pyropheophorbide a, in the blood of photosensitive cattle and sheep.. Standard methanolic solutions of pheophorbide a (25 microM), pyropheophorbide a (25 microM), and phytoporphyrin (<3.7 microM) were prepared. Serum and plasma samples were obtained from cattle (n=5), sheep (n=3), and one alpaca, with clinical facial eczema (i.e. photosensitive), as well as from clinically normal (n=2 of each) adult cows, recently weaned calves, and sheep (controls). Standard solutions of the three metabolites were characterised using high-performance liquid chromatography (HPLC), with mass spectrometry, in conjunction with absorption and emission spectral data, and were compared with sera from photosensitive animals. In the latter, phytoporphyrin was the only metabolite detected. Calibration curves were prepared by adding different ratios of methanol and standard solutions of phytoporphyrin in methanol to diluted serum from control animals. Peak areas of fluorescence spectra were determined in samples from photosensitive animals.. Pheophorbide a and pyropheophorbide a produced typical chlorin spectra, and had excitation/emission maxima of 408/669 nm and 409/669 nm, respectively. Phytoporphyrin showed a typical porphyrin fluorescence spectrum, with excitation/ emission maxima of 425/644 nm. Pyropheophorbide a and phytoporphyrin had very similar chromatographic retention times, the same chemical formula and same mass, but were distinguishable by differences in their absorption spectra. In sera from photosensitive animals, the fluorescence emission at 644 nm was shown to arise solely from phytoporphyrin and not from any other chlorophyll a metabolites. Calibration curves using sera and plasma from control animals gave reliable measurements of phytoporphyrin in the range 0.4-6 microM. The sera of facial eczema-affected cattle and sheep had concentrations of phytoporphyrin ranging from 0.4 to 1.8 and 0.9 to 2.8 microM, respectively. Haemolysed serum samples were not suitable for determination of phytoporphyrin with this method.. A spectrofluorometric method for the quantification of phytoporphyrin in the blood of photosensitive animals has been validated, and can be applied to the measurement of other chlorophyll a metabolites in blood. This will be a useful tool in the further investigation of the cause and pathogenesis of idiopathic photosensitivities of farm animals.

Topics: Animals; Cattle; Chlorophyll; Chlorophyll A; Chromatography, High Pressure Liquid; Fluorescent Antibody Technique; Mass Spectrometry; Molecular Structure; Photosensitivity Disorders

An octaethylporphyrin derivative, 1, possessing an exo-five-membered ring fused at the 13- and 15-positions was oxidized by osmium tetroxide to give two isomeric chlorins, 3 and 5, possessing beta,beta'-dihydroxy groups at the A- and C-rings, respectively. Single dehydration of 2,3-dihydroxychlorin 3 gave a mixture of 2- and 3-(1-hydroxyethyl)porphyrins 7, while that of 12,13-dihydroxychlorin 5 resulted in the sole formation of 131-hydroxyporphyrin 9. The latter was modified smoothly to the phytoporphyrin analogue 2, whose molecular skeleton was similar to that of naturally occurring chlorophylls possessing a 131-oxo group fixed on an exo-five-membered ring.

Topics: Chlorophyll; Porphyrins; Pyrroles

Hepatogenous photosensitization occurs in livestock following damage to the liver or biliary apparatus that results in impaired excretion of phytoporphyrin (phylloerythrin), a photosensitizer. Based on earlier observations that porphyrin-based photosensitizers are substrates of the ATP-binding cassette transporter ABCG2, we examined the ability of the hepatic transporters ABCB1 (P-glycoprotein) and ABCG2 to transport phytoporphyrin. Transport of phytoporphyrin was blocked by the ABCG2-specific inhibitor fumitremorgin C (FTC) in human embryonic kidney cells transfected with full length human ABCG2, while no transport by cells transfected with human ABCB1 was noted. FTC-inhibited transport of phytoporphyrin was also demonstrated in ABCG2-expressing LLC-PK1 pig kidney cells, consistent with the idea that the pig orthologue, like human ABCG2, transports the photosensitizer. ABCG2 expression was confirmed by immunohistochemistry in the hepatocytes of cow, pig and sheep livers. We conclude that phytoporphyrin is a substrate for ABCG2 and that the transporter is likely responsible for its biliary excretion.

Topics: Amino Acid Sequence; Animals; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Cattle; Cell Line; Chlorophyll; Gene Expression Regulation; Humans; Liver; Molecular Sequence Data; Neoplasm Proteins; Organic Anion Transporters; Pancreas; Sheep; Swine

Topics: Animals; Cattle; Cattle Diseases; Chlorophyll; Disease Outbreaks; Photosensitivity Disorders; Porphyrias; Texas

Two types of plant-caused photosensitizations are recognized in livestock: 1) primary, wherein the phototoxic agent in the plant is ingested and reaches the skin chemically unchanged; and 2) secondary, wherein the phototoxic agent in the porphyrin phylloerythrin produced by chlorophyll degradation in ruminant stomachs. Phylloerythrin is normally excreted in bile but is allowed to reach the skin when hepatic damage interferes with the phylloerythrin-excreting mechanism. Primary photosensitizing plant toxins are few, whereas secondary photosensitizations can be caused by damage to the liver by a variety of plant and other toxins. Plants causing each type of photosensitization are discussed and clinical manifestations of the disease in livestock are summarized. Tetradymia species are one of the most economically important causes of phototoxicity in livestock. The etiology of this phototoxic syndrome in sheep and the importance of sagebrush species as preconditioning agents for phototoxicity are discussed.

Topics: Animal Feed; Animals; Chlorophyll; Photosensitivity Disorders; Plants, Toxic; Porphyrias; Porphyrins; Skin Diseases; Sunlight

Certain synthetic and naturally occurring chemicals, particularly those found in some range plants, may interact with livestock and poultry in the presence of activating light to produce photosensitization. Such photosensitization may have serious implications for livestock producers as a result of causing reduced performance of and even death of affected animals. The mechanisms producing photosensitization in livestock and poultry are discussed in context with the chemical nature of major livestock photosensitizers. The possibility that photosensitizing agents for livestock may have toxicologic significance in humans consuming photoactive residues in meat or animal byproducts is considered.

Topics: Animal Feed; Animals; Biotransformation; Cattle; Cattle Diseases; Chemical Phenomena; Chemistry; Chlorophyll; Costs and Cost Analysis; Liver; Photosensitivity Disorders; Plants; Porphyrias; Porphyrins; Poultry Diseases; Sunlight

Under general anaesthesia the common bile duct was ligated in two sheep and two calves. Occlusion of the duct was permanent and was followed by portal fibrosis, proliferation of bile ducts and intrahepatic bile stasis. Mild hepatic cell damage was accompanied by the release of glutamate dehydrogenase, sorbitol dehydrogenase and arginase into serum. The release of gamma-glutamyl transpeptidase was slower but more continuous. One sheep and one calf developed peritonitis associated with the leakage of bile from a biopsy wound in the live. One of these animals and the other two on which biopsy was not performed became photosensitised on exposure to sunlight. The concentration of phylloerythrin was high in serum and urine. All animals became jaundiced and the increased concentration of bilirubin in serum and urine was mainly direct reacting, ie, conjugated with glucuronic acid.

Topics: Animals; Bile; Bilirubin; Cattle; Cattle Diseases; Chlorophyll; Cholestasis; Female; gamma-Glutamyltransferase; Glutamate Dehydrogenase; Jaundice; Oxidoreductases; Photosensitivity Disorders; Porphyrins; Sheep; Sheep Diseases; Sorbitol

Topics: Biological Products; Chlorophyll; Humans; Pigments, Biological

Topics: Bile; Chlorophyll; Pigments, Biological