Mass spectrometric analysis of ptaquiloside, the toxic sesquiterpene from bracken fern.

latiusculum); its structure was elucidated in 1987. The same substance and several analogues have been identified in other Pteridacae. Bracken fern is currently consumed by farm animals, and this causes a number of well-known syndromes in domestic animals. In large ruminants, chronic enzootic haematuria, the clinical expression of multiple neoplasia of the urinary bladder, occurs. The occurrence of this pathology has been associated with the geographic distribution of bracken fern, which is a plant widely distributed all over the world, and with its content of Pta. Pta has been shown in laboratory experiments to be carcinogenic, and it is co-responsible for tumors of urinary bladder in cow; it seems to act synergistically with bovine papilloma virus type 2 (BPV-2), that is a well-known virus associated with neoplastic pathology of the bovine urinary bladder. The carcinogenic properties of Pta have been related to its electrophilic nature, and its capability to react with (alkylate) DNA. The growing public awareness of the risk implied in continuous exposure to carcinogenic substances present in foods has prompted some researchers to evaluate the possibility that Pta may represent a pollutant of foods derived from cattle. This work has also demonstrated a significant increase in gastric cancers ( 2.34) in humans who spend their childhood in bracken-infested areas, and milk has been proposed as the carrier. Indeed, Pta has been recently detected in milk of cows growing in infested areas.