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At least 19 recordsLinked to original sources
PubMed1987

Induction of tumors in rats by bracken fern (Pteridium aquilinum) from Ouro Preto (Minas Gerais, Brazil).

1. The possible carcinogenicity of bracken fern (Pteridium aquilinum, common name: "Broto de Samambaia") which is used as food by the population of Ouro Preto (Minas Gerais, Brazil) and neighboring areas, was studied in rats. 2. Fifteen (6 female and 9 male) 45-day old Wistar rats were fed a diet containing dried bracken fern (5%, w/w) for up to 70 weeks. After death or sacrifice, the animals were carefully examined for tumors in the gastrointestinal tract, bladder, lungs, liver, and kidneys. 3. All experimental animals showed gastrointestinal tract tumors which were located mainly in the ileum. Most of the tumors were malignant lesions (adenocarcinomas and sarcomas), although benign adenomas were also present. One animal developed a lymphoma and none showed vesical tumors. 4. No tumors were detected in 11 control rats (5 female and 6 male). 5. These data clearly demonstrate that Pteridium aquilinum is carcinogenic for rats.

Animals↗
PubMed2005

Kinetics of the natural evolution of hydrogen cyanide in plants in neotropical Pteridium arachnoideum and its ecological significance.

The time-dependent natural release of hydrogen cyanide (HCN) was studied quantitatively using young croziers of the neotropical bracken fern Pteridium arachnoideum. HCN production was quantified in crushed tissue using a flow reactor at 30.0 +/- 0.1 degrees C. Released HCN was carried into appropriate traps with a moist air flow. Aliquots were drawn from the traps at fixed time intervals, and the HCN concentration was evaluated spectroscopically. All available prunasin (Pru), the only cyanogenic glycoside present, underwent decomposition into HCN in less than 1200 min. Fiddleheads (N = 76) contained 1.84-107.70 mg Pru g(1) dw in a continuous fashion suggesting genetic polymorphism. Acyanogenic morphs were rare (1/77). From the kinetics of the samples with Pru content near the median histographic distribution (N = 46), accumulated HCN formation as a function of time, initial velocities, average HCN production rate, and corresponding rate equations were obtained. Initial and average velocities correlated well with total Pru content. The yield of cyanide liberation varied widely between 0.51 and 47.86 microg HCN min(-1) g(-1) dw and was a linear function of [Pru]t. However, the beta-glucosidase enzyme involved in this reaction was not rate limiting and occurs in excess in the natural system. Enzyme activity was found to be independent of [Pru]t. The contribution of HCN as an allomone-upon-request against herbivores was assessed quantitatively. Bracken fiddleheads produced a pulse of HCN soon after tissue injury that waned rapidly, leaving a large portion of intact prunasin to decompose more slowly in the herbivore's lumen. The balance between the external and internal courses was found to depend on the concentration of prunasin in the plant, the amount of crozier eaten, and the time used to consume it.

Biological Evolution↗
PubMed2003

Pteroside A2--a new illudane-type sesquiterpene glucoside from pteridium caudatum L. Maxon, and the spectrometric characterization of caudatodienone.

Fractionation of an extract of Pteridium caudatum L. Maxon. (syn P. aquilinum L. Kuhn var. caudatum) which had earlier yielded the illudane-type sesquiterpene glucosides, ptaquiloside (1a), isoptaquiloside (1b), and caudatoside (1c) afforded a mixture containing 1a and two minor components. Preparative HPLC afforded ptaquiloside Z (1d) and a new pteroside glucoside (pteroside A2) (3e), which was identified using a combination of mass spectral and one- and two-dimensional NMR analyses. The (1)H and (13)C NMR and mass spectrometric characterization of caudatodienone (2b), an unstable dienone derived from the degradation of caudatoside (1c) in pyridine solution, and the GC-MS characterization of some pterosin-type degradation products produced by reacting this solution with cosolvents is also reported.

Chromatography, High Pressure Liquid↗
PubMed1959

Observations on the microanatomy of the spermatozoid of the bracken fern (Pteridium aquilinum).

Salient features of structure of the spermatozoid of a fern (Pteridium aquilinum) have been determined by a combination of visual and ultraviolet microscopy, with electron microscopy of shadow-cast whole mounts and thin sections, using magnifications up to but not exceeding 50,000 diameters. Attention has been concentrated on the arrangement rather than on the internal details of the various parts. The most important component, apart from the spirally wound nucleus, numerous (about 40) cilia, and mitochondria, is a sheet of parallel fibres spirally wound near the surface of a cone of cytoplasm to which all the other major components are in various ways attached. The diameter of the individual fibres is of the order of 200 A. A few details are given of other minor cell constituents including additional mechanical materials, starch-containing leucoplasts, and the smaller cytoplasmic inclusions.

Cell Nucleus↗
PubMed2002

Bracken fern (Pteridium aquilinum) poisoning in cattle in southern Brazil.

Epidemiological data on Pteridium aquilinum intoxication in cattle the state of Santa Catarina were obtained by review of diagnostic records from 1987 to 2001. Of 3,407 necropsied cattle, 244 (7.16%) were diagnosed as intoxicated by Paquilinum; 122 of those were of the hemorrhagic form, 103 had tumors in the upper digestive tract, 19 were cases of chronic hematuria. Annual losses due to this intoxication in this State are estimated at 10,657 cattle. The highest incidence of the hemorrhagic form occurs in 1-3-y-old cattle between March and July, and most cases of tumors of the upper digestive tract affect cattle older than Sy. The highest incidence of digestive tract tumors is at the base of the tongue and pharynx, and the lowest frequency is in the rumen and esophagus. The large economic losses caused PaQuilinum in Santa Catarina call for improved control measures for the disease.

Animals↗
PubMed1995

Bracken fern (Pteridium spp.) carcinogenicity and human health--a brief review.

Bracken fern (Pteridium spp.), one of the most abundant plants on the planet, is well known to cause cancer naturally in sheep and cattle. It contains, in some locations, extremely high concentrations of ptaquiloside which almost certainly is its major carcinogen. Ptaquiloside is transferred through milk. There is epidemiological evidence that the bracken carcinogen, in special situations, may cause cancer in man. Ptaquiloside and its animal models of carcinogenesis also offer good tools for the study of cancer.

Animals↗
PubMed1995

Absence of promoting potential of bracken fern (Pteridium aquilinum) in rat urinary bladder carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)-nitrosamine and uracil.

Conventional studies on bracken fern (Pteridium aquilinum; PA) carcinogenicity have used high dietary concentrations (around 30%) and long-term exposure (up to 52-70 weeks) without consideration of the multistep character of the chemical carcinogenesis process. The present study evaluated specifically the promoting potential of 3-5% dietary crude PA in the rat urinary bladder mucosa in a 32-week-long initiation-promotion assay for chemical carcinogenesis. Initiation of urothelial carcinogenesis was accomplished with N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN). Uracil (U) was provided through the diet in order to expand the population of initiated cells. Seven groups (G) of male Wistar rats were submitted to the following treatments: G1 = BBN (n = 8); G2 = U (n = 10); G3 = BBN-U (n = 9); G4 = BBN-PA-U-PA (n = 16); G5 = PA (n = 8); G6 = BBN-PA (n = 10); G7 = PA-U-PA (n = 12). At the end of the experiment rats presenting epithelial papillary or nodular hyperplasia (PNH), papillomas (PAP), or simultaneous PNH plus PAP numbered, respectively G1: 2-0-1; G2: 0-0-0; G3: 3-0-2; G4: 4-3-2; G5: 1-0-1; G6: 8-0-0; and G7: 0-0-0, with no significant differences in the incidence of lesions among the groups. More frequent and more severe lesions occurred in BBN-initiated animals, predominantly in those also exposed to uracil (G3 and G4). Low-dose crude bracken fern in the diet does not promote rat urinary bladder carcinogenesis after a 32-week period of exposure, even when the initiated urothelial cell population has been expanded through a mechanical stimulus.

Animals↗
PubMed2001

Bracken (Pteridium aquilinum)-induced DNA adducts in mouse tissues are different from the adduct induced by the activated form of the Bracken carcinogen ptaquiloside.

Following treatment with bracken fern (Pteridium aquilinum) extract and bracken spores a number of DNA adducts were detected by (32)P-postlabeling. Three of these adducts have been described previously (Povey et al., Br. J. Cancer (1996) 74, 1342-1348) and in this study, using a slightly different protocol, four new adducts, with higher chromatographic mobility, were detected at levels ranging from 50 to 230% of those previously described. When DNA was treated in vitro with activated ptaquiloside (APT) and analysed by butanol extraction or nuclease P1 treatment, only one adduct was detected by (32)P-postlabeling. This adduct was not present in the DNA from mice treated with bracken fern or spores, suggesting either that bracken contains genotoxins other than ptaquiloside or that the metabolism of ptaquiloside produces genotoxins not reflected by activated ptaquiloside. However, as the ATP-derived adduct has been detected previously in ileal DNA of bracken-fed calves, species-specific differences in the metabolism of bracken genotoxins may exist, thereby leading to differences in their biological outcomes.

Animals↗
PubMed1991

Analysis of Pteridium ribosomal RNA sequences by rapid direct sequencing.

A total of 864 bases from 5 regions interspersed in the 18S and 26S rRNA molecules from various clones of Pteridium covering the general geographical distribution of the genus was analysed using a rapid rRNA sequencing technique. No base difference has been detected amongst the three major lineages, two of which apparently separated before the breakup of the ancient supercontinent, Pangaea. These regions of the rRNA sequences have thus been conserved for at least 160 million years and are here compared with other eukaryotic, especially plant rRNAs.

Biological Evolution↗
PubMed1982

Consumption of poisonous plants (Senecio jacobaea, Symphytum officinale, Pteridium aquilinum, Hypericum perforatum) by rats: chronic toxicity, mineral metabolism, and hepatic drug-metabolizing enzymes.

Effect of dietary tancy ragwort (Senecio jacobaea), comfrey (Symphytum officinale), bracken (Pteridium aquilinum) and alfalfa (Medicago sativa) on hepatic drug-metabolizing enzymes in rats were measured. Tansy ragwort and bracken increased (P less than 0.05) the activity of glutathione transferase and epoxide hydrolase. Comfrey and alfalfa increased (P less than 0.05) the activity of aminopyrine N-demethylase. Feeding bracken or St. John's wort (Hypericum perforatum) in conjunction with tansy ragwort did not influence chronic toxicity of tansy ragwort as assessed by rat survival time. Dietary tansy ragwort resulted in increased (P less than 0.05) hepatic copper levels; the other plants did not affect copper levels. The results do not suggest any major interaction in the toxicity of tansy ragwort with bracken or St. John's wort.

Animals↗
PubMed1998

Ptaquiloside Z, a new toxic unstable sesquiterpene glucoside from the neotropical bracken fern Pteridium aquilinum var. caudatum.

Reversed-phase HPLC fractionation, monitored by brine shrimp bioassay, led to the isolation of a new illudane-type sesquiterpene glucoside, ptaquiloside Z (2), as well as the known bracken carcinogen ptaquiloside (1), from a bioactive aqueous extract of the neotropical bracken fern Pteridium aquilinum var. caudatum (Pteridaceae). The structure of ptaquiloside Z (2) was confirmed by spectroscopic analyses and chemical degradation. Both compounds exhibited similar toxicity (LC50 62.5 micrograms/ml at 24 h and LC50 7.8 micrograms/ml at 48 h) toward brine shrimp.

Animals↗
PubMed1988

Carcinogenicity of bracken fern (Pteridium esculentum) in New Zealand.

Bracken fern (Pteridium esculentum) was harvested from two sites LB and TB one of which (TB) was on a central North Island New Zealand farm where bovine enzootic haematuria (BEH) was known to occur. The fern was dried, ground and incorporated (25% w/w) into a pelleted diet and fed to female rats for a total of 162 days. Fifteen weeks later when the rats were autopsied it was found that numerous tumours, mainly of the ileum and urinary bladder were present in the animals fed the bracken fern from the TB site. Neoplasms were found in 85% of rats from the TB group compared with 11% in the LB group while only a single tumour (a haemangioma of the uterus) was observed in the controls. In all, there were neoplasms in 42, 5 and 1 organ/s from the TB, LB and control rat groups respectively (p<0.001). Analysis of the fern and pellets for ptaquiloside, the carcinogen in bracken fern, showed much higher levels present in the material from the TB site. There was 26 and 2270 microg ptaquiloside/g of dried fern and, for pellets from the same fern, 6.5 and 355 microg ptaquiloside/g of pellets, for one collection from the LB and TB sources respectively.

Journal Article↗
PubMed1983

Aquilide A, a new mutagenic compound isolated from bracken fern (Pteridium aquilinum (L.) Kuhn).

A mutagenic compound, designated aquilide A, was isolated and identified from bracken fern (Pteridium aquilinum (L.) Kuhn). Aquilide A was found to be responsible for greater than 50% of the mutagenic activity observed after incubation of the methanol extract at alkaline conditions. This compound was found to be a potent genotoxic compound in mammalian cells in vitro and therefore, may be responsible for at least part of the carcinogenic activity of bracken. The instability of aquilide A under conditions normally encountered during analytical chemical procedures may explain why so many efforts to elucidate the carcinogenic factor(s) present in bracken have been unsuccessful.

Animals↗
PubMed1976

Identification of carcinogenic tannin isolated from Bracken fern (Pteridium aquilinum).

We attempted to isolate a carcinogenic substance from bracken fern (Pteridium aquilinum), a naturally occurring toxicant responsible for the production of chronic enzootic hematuria and urinary bladder cancer of cattle and carcinogenic for various target organs of several species. Hot methanol extracts of bracken fern were solubilized in water and extracted with chloroform followed by a mixture of n-butanol-butanone (1:1). That fraction was dried and triturated with ether-methanol (4:1), n-butanol, and finally absolute ethanol. The insoluble residue was dissolved in 10% aqueous methanol and passed through Dowex 1 OH-, Dowex 50 H+, or Dowex 1 OH- and then Dowex 50 H+ ion exchange resins. A condensed tannin, isolated from one ot the fractions, was identical to that isolated from bracken fern by the caffeine procedure used for the separation of tannins from other plant constituents. Three systems were used for bioassay; induction of bladder carcinoma by implantation of cholesterol pellets containing bracken fern fractions into the bladder lumens of mice; acute toxicity by ip injection of brachen fern fraction into mice; and growth inhibition of Escherichia coli. The following fractions induced significantly greater incidences of bladder carcinoma than did cholesterol pellets only: tannin, Dowex 50 H+, residue, n-butanol, and methanol. Tiliroside, a component of bracken fern fractions into the bladder lumens of mice; acute genic acid, and quercetin were not carcinogenic. Tannin was the most toxic (mean lethal dose: 0.16 mg/g) and carcinogenic. None of the carcinogenic fractions inhibited growth of E. coli.

Escherichia coli↗
PubMed1987

Assay of ptaquiloside, the carcinogenic principle of bracken, Pteridium aquilinum, by mutagenicity testing in Salmonella typhimurium.

The mutagenicity of ptaquiloside, the carcinogenic principle of Pteridium aquilinum, was tested in Salmonella typhimurium TA100 and TA98. Under weakly basic conditions (pH 8.5), ptaquiloside decomposed into a conjugated dienone (considered to be the ultimate form), which was mutagenic in both strains. A novel bioassay, using the pre-incubation method at pH 8.5 with S. typhimurium tester strains was developed for the assay of ptaquiloside extracted from plants. By this bioassay the ptaquiloside content of ferns collected at different localities during various seasons, and in various parts of the plant was determined. The ubiquitous presence of ptaquiloside in fresh plant materials was confirmed. Bracken processed in alkali was found not to contain the carcinogen.

Carcinogens↗
PubMed1972

Ribonucleic Acid Synthesis Associated with a Developmental Change in the Gametophyte of Pteridium aquilinum.

When bacteria are subjected to step-down conditions, there is an enhanced production of a messenger-type of RNA for a short time after the shift. A cultural shift, which appears to be similar to step-down, is described for gametophytes of Pteridium aquilinum. When the cultures are grown in white light, a population of rapidly dividing cells is produced, whereas in red light cell elongation predominates. If the cultures growing in white light are shifted to red light, a transition occurs which involves a rapid decrease in growth and nucleic acid synthesis. In particular, there is a marked decline in RNA synthesis for a short time following the shift and prior to the initiation of the new mode of growth. It appears that this observed change in RNA synthesis is related to the initiation of the new mode of growth.

Journal Article↗
PubMed1975

Observations on the male nucleus during fertilization in the fern Pteridium aquilinum.

Fertilization of eggs of Pteridium under controlled conditions has revealed that archegonia containing viable eggs require more than 30 min flooding before opening. Syngamy appears to take place by an engulfing action, and no evidence was found of a 'membrane-fusion' kind of conjugation. Although the gametic nucleus lacks a recognizable envelope, as soon as it comes into contact with the female cytoplasm an envelope is reconstituted from an opaque layer at the surface of its chromatin. This membrane also undergoes growth, the outer layer extending into the cytoplasm and surrounding spermatozoid mitochondria. The male envelope remains distinct from the female, and lacks evaginations and well defined pores. The male nucleus lies in irregular loops within a funnel, filled with egg cytoplasm, formed by the microtubular ribbon of the gamete. The mouth of the funnel is bordered by the multi-layered structure. Karyogamy is initiated at the anterior end of the male nucleus, the orifice connecting the 2 nuclei widening from about 0-1 to 2 mum in diameter during fusion. The contents of the male nucleus flow through the mouth of the funnel into the female, the chromatin relaxing locally, but retaining a rod-like form. The envelope of the male nucleus is probably resorbed at the site of junction. There is no evidence that it contributes significantly to the envelope of the zygotic nucleus.

Cell Nucleus↗
PubMed1978

A microtubule--nuclear envelope complex in the spermatozoid of Pteridium.

The microtubules on the outside of the nucleus of the mature spermatozoid of Pteridium form a complex with the envelope, and the perinuclear space is eliminated. These dissimilar components are held firmly together, possibly by hydrophobic bonding. The outer part of the chromatin is also attached to the inner boundary of the envelope, and pulls away when the envelope is detached.

Cell Nucleus↗