QUERCETIN, A RAT INTESTINAL AND BLADDER CARCINOGEN PRESENT IN BRACKEN FERN (PTERIDIUM-AQUILINUM)

Abstract

Albino noninbred weanling male and female rats were fed a basic grain diet (group 1) or a basic diet supplemented with 33% bracken fern [BF (group 2)] or 0.1% quercetin [purity, > 99% (group 3)] for 58 wk. The quantities of quercetin and kaempferol (a close structural analog) in BF as glycosides were 0.57 and 1.1 g, respectively, per kg of dried BF. Estimated mean total cumulative doses (mmol) per rat are presented. Growth of rats fed BF or quercetin was comparable but significantly (P < 0.01) slower after 24 wk than that of group 1. Mean survivals (weeks) of rats of all groups were: group 1, 58 .+-. 7 (SD); group 2, 51 .+-. 13; and group 3, 56 .+-. 8. They were not significantly different, although rats fed BF tended to die earlier secondary to intestinal tumor-induced intussusception and obstruction. The incidences of intestinal or bladder neoplasms in male and female rats are presented. The histopathology of neoplasms of the 2 target organs was identical for rats of groups 2 and 3. Multiple ileal intestinal neoplasms of rats fed quercetin included: adenoma, 4; fibroadenoma, 7; and adenocarcinoma, 9 (with mesenteric metastases, 3). The 5 bladder tumors were papillary or sessile transitional cell carcinomas.