A preliminary study on the carcinogenicity of the common fern Onychium contiguum

Hemorrhagic diathesis in cattle due to consumption of Adiantopsis chlorophylla (Swartz) Fée (Pteridaceae)

An outbreak of acute febrile syndrome associated with coagulopathy and severe pancytopenia occurred in cattle grazing in paddocks with high infestation by Adiantopsis chlorophylla. The administration of the plant to a calf reproduced the same signs and lesions seen in spontaneous cases. Similar syndromes are caused by ptaquiloside from bracken fern. Traces of the ptaquiloside-like molecule caudatoside were detected together with 0.03-0.24 mg/g of it's degradation product pterosin A, in dry fronds of the plant. In conclusion, A. chlorophylla is a cause of hemorrhagic diathesis in cattle.

Allyl-isothiocyanate ameliorates the pre-neoplastic changes induced by the fern Dryopteris nigropalaceae on experimental feeding in Guinea pigs

Enzootic bovine haematuria, caused by long-term ingestion of ferns, is a chronic disease of hill cattle characterized by neoplastic lesions in the urinary bladder. Objectives of this study were to investigate the toxicity potential of long-term feeding of the fern Dryopteris nigropalaceae and effect of allyl isothiocyanate (AITC) to ameliorate fern toxicity and the associated pathological changes. The LC-MS analysis of the fern showed presence of ptaquiloside (4.5 ± 1.0 μg/g) and pterosin B (39 ± 9.1 μg/g). Groups of animals were fed dried fern powder at the dose of 20% w/w in normal feed and treated with and without AITC at graded doses. Long term feeding of fern induced inflammatory and pre-neoplastic lesions in urinary bladder. The important lesions included cystitis, squamous metaplasia and high-grade dysplasia. Urothelium showed positive immunoreactions for nuclear expression of H-ras and p53. However, no mutation suggestive of neoplastic change was observed on partial mRNA sequences analyses of exon 2 of H-ras and 5 or 7&8 of p53 genes. Strikingly, AITC showed dose-dependent amelioration of pre-neoplastic changes in fern-fed animals. In conclusion, AITC is shown to limit pre-neoplastic changes caused by D. nigropalaceae feeding in guinea pigs.

Ferns and lycopods--a potential treasury of anticancer agents but also a carcinogenic hazard

Many species of seedless vascular plants-ferns and lycopods-have been used as food and folk medicine since ancient times. Some of them have become the focus of intensive research concerning their anticancer properties. Studies on the anticancer effect of crude extracts are being increasingly replaced by bioactivity-guided fractionation, as well as detailed assessment of the mechanism of action. Numerous compounds-especially flavonoids such as amentoflavone and protoapigenone, and also simpler phenolic compounds, steroids, alkaloids and terpenoids-were isolated and found to be cytotoxic, particularly pro-apoptotic, or to induce cell cycle arrest in cancer cell lines in vitro. In in vivo experiments, some fern-derived compounds inhibited tumour growth with little toxicity. On the other hand, many ferns-not only the well-known Bracken (Pteridium)-may pose a significant hazard to human health due to the fact that they contain carcinogenic sesquiterpenoids and their analogues. The objective of this review is to summarise the recent state of research on the anticancer properties of ferns and lycopods, with a focus on their characteristic bioactive constituents. The carcinogenic hazard posed by ferns is also mentioned.

The environmental and human effects of ptaquiloside-induced enzootic bovine hematuria: a tumorous disease of cattle

In this review, we address the major aspects of enzootic bovine hematuria and have placed special emphasis on describing the etiology, human health implications, and advanced molecular diagnosis of the disease.Enzootic bovine hematuria (EBH) is a bovine disease characterized by the intermittent presence of blood in the urine and is caused by malignant lesions in the urinary bladder. This incurable disease is a serious malady in several countries across many continents. Accurate early-stage diagnosis of the disease is possible by applying advanced molecular techniques, e.g., detection of genetic mutations in the urine of cows from endemic areas. Use of such diagnostic approaches may help create an effective therapy against the disease.There is a consensus that EBH is caused primarily by animals consuming bracken fern (P. aquilinum) as they graze. The putative carcinogen in bracken is ptaquiloside(PT), a glycoside. However, other bracken constituents like quercetin, isoquercetin,ptesculentoside, caudatoside, astragalin, and tannins may also be carcinogenic.Studies are needed to identify the role of other metabolites in inducing urinary bladder carcinogenesis.The bovine papilloma virus is also thought to be an associated etiology in causing EBH in cattle. There is growing alarm that these fern toxins and their metabolites reach and contaminate the soil and water environment and that the carcinogen (PT)is transmitted via cow's milk to the human food chain, where it may now pose a threat to human health. An increased incidence of gastric and esophageal cancer has been recorded in humans consuming bracken ferns, and among those living for long periods in areas infested with bracken ferns.Although preliminary therapeutic vaccine trials with inactivated BPV-2 against EBH have been performed, further work is needed to standardize and validate vaccine doses for animals.

Exposure to the fern Onychium contiguum causes increase in lipid peroxidation and alters antioxidant status in urinary bladder

The status of lipid peroxidation, glutathione, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, superoxide dismutase, catalase, ascorbic acid, and alpha-tocopherol was studied in the urinary bladder of guinea pigs exposed to the carcinogenic fern Onychium contiguum. There was significant increase in the preformed lipid peroxides in the urinary bladders from fern exposed animals. The amount of lipid peroxides produced on incubation of urinary bladder homogenates with or without catalyst was significantly higher in the fern exposed animals. The concentrations of glutathione and alpha-tocopherol and the activities of glutathione reductase and catalase were elevated in the urinary bladders of the animals exposed to the fern. No effect was observed on the concentration of ascorbic acid and the activities of glutathione peroxidase, glutathione-S-transferase, and superoxide dismutase. It is summarized that the fern toxins increased oxidative stress in the urinary bladder and antioxidant status was altered. However, the altered antioxidant status did not provide protection from the toxin induced injury. Histopathology of the urinary bladder in the fern exposed animals revealed oedema, haemorrhages, and congestion. This is the first study to show increase in lipid peroxidation along with altered antioxidant status in the urinary bladder of fern exposed animals.

Ultrasonographic evaluation of urinary bladder in normal, fern fed and enzootic bovine haematuria-affected cattle

A total of 19 adult hill cattle of both sexes were subjected to trans-rectal ultrasound scanning of urinary bladder to evaluate bladder wall thickness and the presence of space-occupying lesions. The animals were divided into four groups. Eight apparently healthy hill cattle maintained under standard ration served as control (group I) and the remaining II animals were divided into three groups (II, III and IV). Group II animals (n = 8) were fed with different type of ferns which were further divided into subgroups II-P, -D and -B and fed with Polystichum squarrosom (n = 2). Dryopteris juxtaposita (n = 2) and Pteridium aquilinum (n = 4) ferns, respectively. The one animal in group III was a natural case of enzootic bovine haematuria (EBH) and the two animals in group IV were natural cases of microscopic EBH fed with Polystichum squarrosum fern. In group I animals, the average bladder wall thickness was 1.45 mm. The delineation of the bladder wall was uniformly smooth and the echo pattern of the bladder was homogeneously black, which was suggestive of clear urine content. In group II (P, D and B) the average bladder wall thickness of the six animals was 1.87 mm and the sonographic features were within normal limit when compared with controls. In two of the animals of group II-B, the bladder wall was apparently thick (4.36 mm) and there was no intraluminal mass except at one or two focal elevated points. Animals of groups III and IV showed the average bladder wall thickness of 4.86 mm and were characterized by the presence of irregular sessile masses extending into the bladder lumen. The homogeneous anechoic area was reduced centrally due to the presence of a hypoechoic soft tissue mass all around the bladder wall. Post-sonographic urinalysis, biopsy and necropsy of selected cases further confirmed the sonographic findings.